Weighted composition operators from Bergman-type spaces into ...

Indian Academy of Sciences (India)

Weighted composition operators from Bergman-type spaces into Bloch spaces and little. Bloch spaces are characterized by function theoretic properties of their inducing maps. Keywords. Weighted composition operator; Bergman-type space; Bloch space. 1. Introduction. Let D be the open unit disk in the complex plane C.

Space structure of the glow discharge with free side boundary

International Nuclear Information System (INIS)

Yatsenko, N.A.

1995-01-01

The main purpose of this work is to reveal physical reasons, which are responsible for the formation of space structure of glow type discharge with free side boundary, both in DC and in RF electric fields. By now extensive experimental material have been accumulated in discharge physics. Also many theoretical models have been proposed for describing separate parts of discharge with the cold electrodes (cathode and anode regions, positive column and transition zones - glow luminescence and Farraday's dark space of DC-discharge, electrode regions and plasma column of RF capacitive discharge). As this takes place, the majority of known works are devoted to some one part of gas discharge - positive column, electrode regions, transition zones and so on. At the same time just now we don't know anything about space structure of free, steady-state gas discharge of glow type, as a whole, especially when the pressure p much-gt 1 Torr

The Space Station as a Construction Base for Large Space Structures

Science.gov (United States)

Gates, R. M.

1985-01-01

The feasibility of using the Space Station as a construction site for large space structures is examined. An overview is presented of the results of a program entitled Definition of Technology Development Missions (TDM's) for Early Space Stations - Large Space Structures. The definition of LSS technology development missions must be responsive to the needs of future space missions which require large space structures. Long range plans for space were assembled by reviewing Space System Technology Models (SSTM) and other published sources. Those missions which will use large space structures were reviewed to determine the objectives which must be demonstrated by technology development missions. The three TDM's defined during this study are: (1) a construction storage/hangar facility; (2) a passive microwave radiometer; and (3) a precision optical system.

Boundedness and compactness of a new product-type operator from a general space to Bloch-type spaces

Directory of Open Access Journals (Sweden)

Stevo Stević

2016-09-01

Full Text Available Abstract We characterize the boundedness and compactness of a product-type operator, which, among others, includes all the products of the single composition, multiplication, and differentiation operators, from a general space to Bloch-type spaces. We also give some upper and lower bounds for the norm of the operator.

Composition operators between Bloch type spaces and Zygmund ...

Indian Academy of Sciences (India)

MS received 1 September 2009; revised 31 March 2011. Abstract. The boundedness and compactness of composition operators between. Bloch type spaces and Zygmund spaces of holomorphic functions in the unit ball are characterized in the paper. Keywords. Composition operator; Bloch type space; Zygmund space. 1.

Space dissipative structures

International Nuclear Information System (INIS)

Chernousenko, V.M.; Kuklin, V.M.; Panachenko, I.P.; Vorob'yov, V.M.

1990-01-01

This paper reports on a wide spectrum of oscillations that is excited due to the evolution instabilities, being in a weak above-threshold state, in the inequilibrium media with decaying spectrum. In this case the pumping, whose part is played by an intensive wave or occupation inversion in the active medium, synchronized the phases of excited modes and, thus, forms the space dissipative structure of the field. In dissipative nonlinear media with nondecaying spectrum the space structures, formed due to the development of instability, experience small-scale hexagonal modulation

Hyperbolic spaces are of strictly negative type

DEFF Research Database (Denmark)

Hjorth, Poul G.; Kokkendorff, Simon L.; Markvorsen, Steen

2002-01-01

We study finite metric spaces with elements picked from, and distances consistent with, ambient Riemannian manifolds. The concepts of negative type and strictly negative type are reviewed, and the conjecture that hyperbolic spaces are of strictly negative type is settled, in the affirmative....... The technique of the proof is subsequently applied to show that every compact manifold of negative type must have trivial fundamental group, and to obtain a necessary criterion for product manifolds to be of negative type....

Combining different types of scale space interest points using canonical sets

NARCIS (Netherlands)

Kanters, F.M.W.; Denton, T.; Shokoufandeh, A.; Florack, L.M.J.; Haar Romenij, ter B.M.; Sgallari, F.; Murli, A.; Paragios, N.

2007-01-01

Scale space interest points capture important photometric and deep structure information of an image. The information content of such points can be made explicit using image reconstruction. In this paper we will consider the problem of combining multiple types of interest points used for image

Synthesizing lattice structures in phase space

International Nuclear Information System (INIS)

Guo, Lingzhen; Marthaler, Michael

2016-01-01

In one dimensional systems, it is possible to create periodic structures in phase space through driving, which is called phase space crystals (Guo et al 2013 Phys. Rev. Lett. 111 205303). This is possible even if for particles trapped in a potential without periodicity. In this paper we discuss ultracold atoms in a driven optical lattice, which is a realization of such a phase space crystals. The corresponding lattice structure in phase space is complex and contains rich physics. A phase space lattice differs fundamentally from a lattice in real space, because its coordinate system, i.e., phase space, has a noncommutative geometry, which naturally provides an artificial gauge (magnetic) field. We study the behavior of the quasienergy band structure and investigate the dissipative dynamics. Synthesizing lattice structures in phase space provides a new platform to simulate the condensed matter phenomena and study the intriguing phenomena of driven systems far away from equilibrium. (paper)

Photovoltaic properties of ZnO nanorods/p-type Si heterojunction structures

Directory of Open Access Journals (Sweden)

Rafal Pietruszka

2014-02-01

Full Text Available Selected properties of photovoltaic (PV structures based on n-type zinc oxide nanorods grown by a low temperature hydrothermal method on p-type silicon substrates (100 are investigated. PV structures were covered with thin films of Al doped ZnO grown by atomic layer deposition acting as transparent electrodes. The investigated PV structures differ in terms of the shapes and densities of their nanorods. The best response is observed for the structure containing closely-spaced nanorods, which show light conversion efficiency of 3.6%.

Structure and fluid evolution of Yili basin and their relation to sandstone type uranium mineralization

International Nuclear Information System (INIS)

Wang Juntang; Wang Chengwei; Feng Shirong

2008-01-01

Based on the summary of strata and structure distribution of Yili basin, the relation of structure and fluid evolution to sandstone type ur alum mineraliation are analyzed. It is found that uranium mineralization in Yili basin experienced ore hosting space forming, pre-alteration of hosting space, hosting space alteration and uranium formation stages. (authors)

CMsearch: simultaneous exploration of protein sequence space and structure space improves not only protein homology detection but also protein structure prediction

KAUST Repository

Cui, Xuefeng

2016-06-15

Motivation: Protein homology detection, a fundamental problem in computational biology, is an indispensable step toward predicting protein structures and understanding protein functions. Despite the advances in recent decades on sequence alignment, threading and alignment-free methods, protein homology detection remains a challenging open problem. Recently, network methods that try to find transitive paths in the protein structure space demonstrate the importance of incorporating network information of the structure space. Yet, current methods merge the sequence space and the structure space into a single space, and thus introduce inconsistency in combining different sources of information. Method: We present a novel network-based protein homology detection method, CMsearch, based on cross-modal learning. Instead of exploring a single network built from the mixture of sequence and structure space information, CMsearch builds two separate networks to represent the sequence space and the structure space. It then learns sequence–structure correlation by simultaneously taking sequence information, structure information, sequence space information and structure space information into consideration. Results: We tested CMsearch on two challenging tasks, protein homology detection and protein structure prediction, by querying all 8332 PDB40 proteins. Our results demonstrate that CMsearch is insensitive to the similarity metrics used to define the sequence and the structure spaces. By using HMM–HMM alignment as the sequence similarity metric, CMsearch clearly outperforms state-of-the-art homology detection methods and the CASP-winning template-based protein structure prediction methods.

Finite Metric Spaces of Strictly negative Type

DEFF Research Database (Denmark)

Hjorth, Poul G.

If a finite metric space is of strictly negative type then its transfinite diameter is uniquely realized by an infinite extent (“load vector''). Finite metric spaces that have this property include all trees, and all finite subspaces of Euclidean and Hyperbolic spaces. We prove that if the distance...

Spinor structures on homogeneous spaces

International Nuclear Information System (INIS)

Lyakhovskii, V.D.; Mudrov, A.I.

1993-01-01

For multidimensional models of the interaction of elementary particles, the problem of constructing and classifying spinor fields on homogeneous spaces is exceptionally important. An algebraic criterion for the existence of spinor structures on homogeneous spaces used in multidimensional models is developed. A method of explicit construction of spinor structures is proposed, and its effectiveness is demonstrated in examples. The results are of particular importance for harmonic decomposition of spinor fields

Development, characteristics and comparative structural analysis of tensegrity type cable domes

Directory of Open Access Journals (Sweden)

Nenadović Aleksandra

2010-01-01

Full Text Available Tensegrity type cable domes are three-dimensional structural configurations, prestressed inside the perimeter compression ring, in which the continuous tension throughout the roof structure is made by continuous tension cables and discontinuous compression struts. These kinds of structures can be formed like spatially triangulated networks or like networks nontriangulated in space. This paper examines some effects of network geometry on the behaviour and structural efficiency of tensegrity type cable domes. In this paper the roof cover is considered non-interactive with the supporting structure, unlike rigidly clad tensegrity type cable domes. Since the main bearing elements of tensegrity type cable domes are prestressed cables, they show non-linear load deformation and rely upon geometric stiffness. A geometrically non-linear analysis of non-triangulated and triangulated structures for different load conditions was conducted employing a computer program based on the perturbation theory. The incrementally-iterative procedure, with an approximation of the stiffness matrix by combining the elastic and geometric stiffness matrix, allows detection of structural instabilities.

Type IIA orientifolds on SU(2)-structure manifolds

Energy Technology Data Exchange (ETDEWEB)

Danckaert, Thomas

2010-11-15

We investigate the possible supersymmetry-preserving orientifold projections of type IIA string theory on a six-dimensional background with SU(2)-structure. We find two categories of projections which preserve half of the low-energy supersymmetry, reducing the effective theory from an N=4 supergravity theory, to an N=2 supergravity. For these two cases, we impose the projection on the low-energy spectrum and reduce the effective N=4 supergravity action accordingly. We can identify the resulting gauged N=2 supergravity theory and bring the action into canonical form. We compute the scalar moduli spaces and characterize the gauged symmetries in terms of the geometry of these moduli spaces. Due to their origin in N=4 supergravity, which is a highly constrained theory, the moduli spaces are of a very simple form. We find that, for suitable background manifolds, isometries in all scalar sectors can become gauged. The obtained gaugings share many features with those of N=2 supergravities obtained previously from other G-structure compactifications. (orig.)

Green functions in Bianci-type spaces

International Nuclear Information System (INIS)

Bukhbinder, I.L.; Kirillova, E.N.

1988-01-01

The theory of free scalar field with conformal connection in distorted space - time with Bianci 1 type metrics is considered. The presentation of the Green functions G-tilde approximately in in in the form of integral from the Schwinger - De Witt kernel over the contour in the plane of complex values of eigentime is obtained. The way, in which the transfer from the Green function in space with Euclidean signature to the Green functions in space with Minkowski signature and vice versa is realized, has been shown

An optimum organizational structure for a large earth-orbiting multidisciplinary Space Base

Science.gov (United States)

Ragusa, J. M.

1973-01-01

The purpose of this exploratory study was to identify an optimum hypothetical organizational structure for a large earth-orbiting multidisciplinary research and applications (R&A) Space Base manned by a mixed crew of technologists. Since such a facility does not presently exist, in situ empirical testing was not possible. Study activity was, therefore, concerned with the identification of a desired organizational structural model rather than the empirical testing of it. The essential finding of this research was that a four-level project type 'total matrix' model will optimize the efficiency and effectiveness of Space Base technologists.

Optimal Embeddings of Bessel-Potential-Type Spaces into Generalized Hölder Spaces Involving k-Modulus of Smoothness

Czech Academy of Sciences Publication Activity Database

Gogatishvili, Amiran; Neves, J. S.; Opic, Bohumír

2010-01-01

Roč. 32, č. 3 (2010), s. 201-228 ISSN 0926-2601 R&D Projects: GA ČR GA201/05/2033; GA ČR GA201/08/0383 Institutional research plan: CEZ:AV0Z10190503 Keywords : slowly varying functions * Lorentz-Karamata spaces * Rearrangement-invariant Banach function spaces * Bessel potentials * (fractional) Sobolev-type spaces * Hölder-type spaces * Zygmund-type spaces Subject RIV: BA - General Mathematics Impact factor: 0.853, year: 2010 http://link.springer.com/article/10.1007%2Fs11118-009-9148-2

Dynamical structure of space and time

International Nuclear Information System (INIS)

Sannikov-Proskuryakov, S.S.

2000-01-01

A mathematically correct solution of the problem of ultraviolet divergences requires a radical change of our ideas on space and matter. We show that the space is a discontinuum in small which is the carrier of a new dynamical structure. Taking into account this structure, a new theory of elementary particles can be suggested

Development of a swim-type ROV for narrow space inspection

International Nuclear Information System (INIS)

Okada, Satoshi; Otani, Kenichi; Kobayashi, Ryosuke; Ohno, Kazunori

2017-01-01

The swim-type remotely operated vehicle (ROV) for inspection of narrow spaces in nuclear power plants has been developed. Many structures are crowded in a confined space at regular intervals in the bottom area of a reactor. So, the thickness of the ROV shape is an important design point to ensure that the ROV can move in the space. The developed ROV has a three-dimensional swimming mechanism using six thrusters, three cameras for observing the position while moving and for making inspections easily, and a localization system. The localization system combines two elements: a gyroscope to detect the progression direction; and a slit laser that detects the progression distance using the optical cutting method. The localization method is called the modified inertial navigation (MIN) method and it was evaluated in a mock-up examination. The ROV was able to move smoothly using the MIN method and its position could be detected without making a mistake in the route followed. (author)

The indentification of Jueluotage V-type structure in Xinjiang and its orderness

International Nuclear Information System (INIS)

Fang Maolong; Sun Wenpeng; Cai Wenbo; Xu Daoyi

2005-01-01

Based on the interpretation of satellite image and field checking in Jueluotage area, Xinjiang, it is thought that the sublatitudinal arc fault zones have been formed since Mesozoic through the evolution of the NWW-trending and NEE-trending faults occurring in pre-Mesozoic time. These three sets of faults comprise the Jueluotage 'V-type structure' formed by the NW-trending structural stress field and drastically activated since Neocene. The Jueluotage V-type structure is expressed in time as an ordered process, and in space as an ordered arrangement and an ordered evolution direction, and characterizes the Information Ordered Series (IOS) of the evolution process of fault structure. (authors)

Emulating a flexible space structure: Modeling

Science.gov (United States)

Waites, H. B.; Rice, S. C.; Jones, V. L.

1988-01-01

Control Dynamics, in conjunction with Marshall Space Flight Center, has participated in the modeling and testing of Flexible Space Structures. Through the series of configurations tested and the many techniques used for collecting, analyzing, and modeling the data, many valuable insights have been gained and important lessons learned. This paper discusses the background of the Large Space Structure program, Control Dynamics' involvement in testing and modeling of the configurations (especially the Active Control Technique Evaluation for Spacecraft (ACES) configuration), the results from these two processes, and insights gained from this work.

Structure of twistor and H-spaces

International Nuclear Information System (INIS)

Lugo, G.G.

1979-01-01

In chapter one, we review briefly the spinor and twistor formalisms in general relativity. Following some suggestions of A.H. Taub, we show that the local twistor structure of a general curved space-time is closely related to the conformal structure used by B.G. Schmidt to define conformal infinity. In particular, we prove that the normal Cartan connection of the conformal bundle coincides with the connection which gives the covariant derivative of local twistors. In chapter two, we use the results of E.T. Newman and J. Plebanski to construct some explicit self-dual metrics. These solutions are of interest because they are good candidates for what we would like to call asymptotically flat H-spaces. Furthermore, by a closer look at these metrics, we may gain more insight into the behavior of twistor spaces near the boundary. In chapter three, we study the geometric structure of twistor spaces associated with asymptotically flat space-times. We show that the space of asymptotic projective twistors, PT + , is an Einstein Kaehler manifold of constant holomorphic sectional curvature. We also give a brief description of the twistor space construction of the metrics in chapter two. In chapter four, we apply the Chern-Moser theory of the pseudoconformal geometry of real hypersurfaces in complex manifolds to study the structure of the boundary PN of PT + . Using some ideas due to S. Webster, we show that the Chern-Moser curvature invariants of PN coincide with the Kaehler curvature invariants of PT + . From the results of chapter three, we deduce that the pseudoconformal geodesics (chains) of the boundary are nicely behaved

Moduli spaces of convex projective structures on surfaces

DEFF Research Database (Denmark)

Fock, V. V.; Goncharov, A. B.

2007-01-01

We introduce explicit parametrisations of the moduli space of convex projective structures on surfaces, and show that the latter moduli space is identified with the higher Teichmüller space for defined in [V.V. Fock, A.B. Goncharov, Moduli spaces of local systems and higher Teichmüller theory, math.......AG/0311149]. We investigate the cluster structure of this moduli space, and define its quantum version....

q-deformed phase-space and its lattice structure

International Nuclear Information System (INIS)

Wess, J.

1998-01-01

Quantum groups lead to an algebraic structure that can be realized on quantum spaces. These are non-commutative spaces that inherit a well-defined mathematical structure from the quantum group symmetry. In turn, such quantum spaces can be interpreted as non-commutative configuration spaces for physical systems. We study the non-commutative Euclidean space that is based on the quantum group SO q (3)

Weighted Differentiation Composition Operator from Logarithmic Bloch Spaces to Zygmund-Type Spaces

Directory of Open Access Journals (Sweden)

Huiying Qu

2014-01-01

Full Text Available Let H( denote the space of all holomorphic functions on the unit disk of ℂ, u∈H( and let  n be a positive integer, φ a holomorphic self-map of , and μ a weight. In this paper, we investigate the boundedness and compactness of a weighted differentiation composition operator φ,unf(z=u(zf(n(φ(z,f∈H(, from the logarithmic Bloch spaces to the Zygmund-type spaces.

Broken symmetry within crystallographic super-spaces: structural and dynamical aspects

International Nuclear Information System (INIS)

Mariette, Celine

2013-01-01

Aperiodic crystals have the property to possess long range order without translational symmetry. These crystals are described within the formalism of super-space crystallography. In this manuscript, we will focus on symmetry breaking which take place in such crystallographic super-space groups, considering the prototype family of n-alkane/urea. Studies performed by X-ray diffraction using synchrotron sources reveal multiple structural solutions implying or not changes of the dimension of the super-space. Once the characterization of the order parameter and of the symmetry breaking is done, we present the critical pre-transitional phenomena associated to phase transitions of group/subgroup types. Coherent neutron scattering and inelastic X-ray scattering allow a dynamical analysis of different kind of excitations in these materials (phonons, phasons). The inclusion compounds with short guest molecules (alkane C n H 2n+2 , n varying from 7 to 13) show at room temperature unidimensional 'liquid-like' phases. The dynamical disorder along the incommensurate direction of these materials generates new structural solutions at low temperature (inter-modulated monoclinic composite, commensurate lock-in). (author) [fr

Space-planning and structural solutions of low-rise buildings: Optimal selection methods

Science.gov (United States)

Gusakova, Natalya; Minaev, Nikolay; Filushina, Kristina; Dobrynina, Olga; Gusakov, Alexander

2017-11-01

The present study is devoted to elaboration of methodology used to select appropriately the space-planning and structural solutions in low-rise buildings. Objective of the study is working out the system of criteria influencing the selection of space-planning and structural solutions which are most suitable for low-rise buildings and structures. Application of the defined criteria in practice aim to enhance the efficiency of capital investments, energy and resource saving, create comfortable conditions for the population considering climatic zoning of the construction site. Developments of the project can be applied while implementing investment-construction projects of low-rise housing at different kinds of territories based on the local building materials. The system of criteria influencing the optimal selection of space-planning and structural solutions of low-rise buildings has been developed. Methodological basis has been also elaborated to assess optimal selection of space-planning and structural solutions of low-rise buildings satisfying the requirements of energy-efficiency, comfort and safety, and economical efficiency. Elaborated methodology enables to intensify the processes of low-rise construction development for different types of territories taking into account climatic zoning of the construction site. Stimulation of low-rise construction processes should be based on the system of approaches which are scientifically justified; thus it allows enhancing energy efficiency, comfort, safety and economical effectiveness of low-rise buildings.

Lightweight Space Tug body structure

International Nuclear Information System (INIS)

Lager, J.R.

1976-01-01

Lightweight honeycomb sandwich construction using a wide variety of metal and fibrous composite faceskins was used in the design of a typical Space Tug skirt structure. Relatively low magnitude combined loading of axial compression and torsion resulted in designs using ultrathin faceskins, light-weight honeycomb cores, and thin faceskin/core adhesive bond layers. Two of the designs with metal faceskins (aluminum and titanium) and four with fibrous composite faceskins (using combinations of fiberglass, boron, and graphite) were evaluated through the fabrication and structural test of a series of small development panels. The two most promising concepts with aluminum and graphite/epoxy faceskins, were further evaluated through the fabrication and structural test of larger compression and shear panels. All panels tested exceeded design ultimate load levels, thereby, verifying the structural integrity of the selected designs. Projected skirt structural weights for the graphite/epoxy and aluminum concepts fall within original weight guidelines established for the Space Tug vehicle

The spectra of type IIB flux compactifications at large complex structure

International Nuclear Information System (INIS)

Brodie, Callum; Marsh, M.C. David

2016-01-01

We compute the spectra of the Hessian matrix, H, and the matrix M that governs the critical point equation of the low-energy effective supergravity, as a function of the complex structure and axio-dilaton moduli space in type IIB flux compactifications at large complex structure. We find both spectra analytically in an h − 1,2 +3 real-dimensional subspace of the moduli space, and show that they exhibit a universal structure with highly degenerate eigenvalues, independently of the choice of flux, the details of the compactification geometry, and the number of complex structure moduli. In this subspace, the spectrum of the Hessian matrix contains no tachyons, but there are also no critical points. We show numerically that the spectra of H and M remain highly peaked over a large fraction of the sampled moduli space of explicit Calabi-Yau compactifications with 2 to 5 complex structure moduli. In these models, the scale of the supersymmetric contribution to the scalar masses is strongly linearly correlated with the value of the superpotential over almost the entire moduli space, with particularly strong correlations arising for g s <1. We contrast these results with the expectations from the much-used continuous flux approximation, and comment on the applicability of Random Matrix Theory to the statistical modelling of the string theory landscape.

Structure of a fibronectin type III-like module from Clostridium thermocellum

International Nuclear Information System (INIS)

Alahuhta, Markus; Xu, Qi; Brunecky, Roman; Adney, William S.; Ding, Shi-You; Himmel, Michael E.; Lunin, Vladimir V.

2010-01-01

The 1.6 Å resolution structure of a fibronectin type III-like module from Clostridium thermocellum with two molecules in the asymmetric unit is reported. The 1.6 Å resolution structure of a fibronectin type III-like module from Clostridium thermocellum with two molecules in the asymmetric unit is reported. The crystals used for data collection belonged to space group P2 1 2 1 2 1 , with unit-cell parameters a = 35.43, b = 45.73, c = 107.72 Å, and the structure was refined to an R factor of 0.166. Structural comparisons found over 800 similar structures in the Protein Data Bank. The broad range of different proteins or protein domains with high structural similarity makes it especially demanding to classify these proteins. Previous studies of fibronectin type III-like modules have indicated that they might function as ligand-binding modules, as a compact form of peptide linkers or spacers between other domains, as cellulose-disrupting modules or as proteins that help large enzyme complexes remain soluble

Autonomous Assembly of Structures in Space

Data.gov (United States)

National Aeronautics and Space Administration — In-orbit assembly of structures is a task that must be performed by space-walking humans, and yet it is costly, time-consuming, and potentially dangerous. Assembly...

Classifying spaces of degenerating polarized Hodge structures

CERN Document Server

Kato, Kazuya

2009-01-01

In 1970, Phillip Griffiths envisioned that points at infinity could be added to the classifying space D of polarized Hodge structures. In this book, Kazuya Kato and Sampei Usui realize this dream by creating a logarithmic Hodge theory. They use the logarithmic structures begun by Fontaine-Illusie to revive nilpotent orbits as a logarithmic Hodge structure. The book focuses on two principal topics. First, Kato and Usui construct the fine moduli space of polarized logarithmic Hodge structures with additional structures. Even for a Hermitian symmetric domain D, the present theory is a refinem

Particles and Dirac-type operators on curved spaces

International Nuclear Information System (INIS)

Visinescu, Mihai

2003-01-01

We review the geodesic motion of pseudo-classical particles in curved spaces. Investigating the generalized Killing equations for spinning spaces, we express the constants of motion in terms of Killing-Yano tensors. Passing from the spinning spaces to the Dirac equation in curved backgrounds we point out the role of the Killing-Yano tensors in the construction of the Dirac-type operators. The general results are applied to the case of the four-dimensional Euclidean Taub-Newman-Unti-Tamburino space. From the covariantly constant Killing-Yano tensors of this space we construct three new Dirac-type operators which are equivalent with the standard Dirac operator. Finally the Runge-Lenz operator for the Dirac equation in this background is expressed in terms of the fourth Killing-Yano tensor which is not covariantly constant. As a rule the covariantly constant Killing-Yano tensors realize certain square roots of the metric tensor. Such a Killing-Yano tensor produces simultaneously a Dirac-type operator and the generator of a one-parameter Lie group connecting this operator with the standard Dirac one. On the other hand, the not covariantly constant Killing-Yano tensors are important in generating hidden symmetries. The presence of not covariantly constant Killing-Yano tensors implies the existence of non-standard supersymmetries in point particle theories on curved background. (author)

Space-time structure

CERN Document Server

Schrödinger, Erwin

1985-01-01

In response to repeated requests this classic book on space-time structure by Professor Erwin Schrödinger is now available in the Cambridge Science Classics series. First published in 1950, and reprinted in 1954 and 1960, this lucid and profound exposition of Einstein's 1915 theory of gravitation still provides valuable reading for students and research workers in the field.

Determination of a new structure type in the Sc–Fe–Ge–Sn system

International Nuclear Information System (INIS)

Brgoch, Jakoah; Ran, Sheng; Thimmaiah, Srinivasa; Canfield, Paul C.; Miller, Gordon J.

2013-01-01

Highlights: ► A new structure type with the composition Sc 4 Fe 5 Ge 6.10(3) Sn 1.47(2) . ► Crystallizes in the space group Immm (No. 71, oI144). ► Sample obtained using a reactive Sn flux. ► Electronic structure calculations indicate polar intermetallic bonding network. - Abstract: A new structure type has been discovered in the system Sc–Fe–Ge–Sn by employing Sn as a flux medium. According to single crystal X-ray diffraction, the new structure has a composition of Sc 4 Fe 5 Ge 6.10(3) Sn 1.47(2) and crystallizes in the space group Immm (No. 71, oI144) with lattice parameters of a = 5.230(1) Å, b = 13.467(3) Å, and c = 30.003(6) Å. The structure is composed of square anti-prismatic clusters that are condensed into zig-zag chains along the [0 1 0] direction. These chains are further condensed through a split Sn/Ge position, forming a three-dimensional network. Magnetization measurements indicate an antiferromagnetic phase transition near 240 K. Electronic structure calculations identified the most favorable bonding network in this new system. Using crystal orbital Hamilton population (COHP) curves and their integrated values (ICOHP), a polar intermetallic bonding network involving Sc–Ge as well as Fe–Sn and Fe–Ge contacts can be assigned to this new structure type.

Finite Metric Spaces of Strictly Negative Type

DEFF Research Database (Denmark)

Hjorth, Poul; Lisonek, P.; Markvorsen, Steen

1998-01-01

of Euclidean spaces. We prove that, if the distance matrix is both hypermetric and regular, then it is of strictly negative type. We show that the strictly negative type finite subspaces of spheres are precisely those which do not contain two pairs of antipodal points. In connection with an open problem raised...

Parovičenko spaces with structures

Czech Academy of Sciences Publication Activity Database

Kubiś, Wieslaw; Kucharski, A.; Turek, S.

2014-01-01

Roč. 108, č. 2 (2014), s. 989-1004 ISSN 1578-7303 R&D Projects: GA ČR(CZ) GAP201/12/0290 Institutional support: RVO:67985840 Keywords : structured compact space * normally supercompact space * median space Subject RIV: BA - General Mathematics Impact factor: 0.776, year: 2014 http://link.springer.com/article/10.1007%2Fs13398-013-0156-0

In-Space Structural Assembly: Applications and Technology

Science.gov (United States)

Belvin, W. Keith; Doggett, Bill R.; Watson, Judith J.; Dorsey, John T.; Warren, Jay; Jones, Thomas C.; Komendera, Erik E.; Mann, Troy O.; Bowman, Lynn

2016-01-01

As NASA exploration moves beyond earth's orbit, the need exists for long duration space systems that are resilient to events that compromise safety and performance. Fortunately, technology advances in autonomy, robotic manipulators, and modular plug-and-play architectures over the past two decades have made in-space vehicle assembly and servicing possible at acceptable cost and risk. This study evaluates future space systems needed to support scientific observatories and human/robotic Mars exploration to assess key structural design considerations. The impact of in-space assembly is discussed to identify gaps in structural technology and opportunities for new vehicle designs to support NASA's future long duration missions.

Embeddings relations between weighted complementary Local Morrey-type spaces and weighted local Morrey-type spaces

Czech Academy of Sciences Publication Activity Database

Gogatishvili, Amiran; Mustafayev, R.Ch.; Ünver, T.

2017-01-01

Roč. 8, č. 1 (2017), s. 34-49 ISSN 2077-9879 R&D Projects: GA ČR GA13-14743S Institutional support: RVO:67985840 Keywords : local Morrey-type spaces * embeddings * iterated Hardy inequalities Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics http://www.mathnet.ru/ php /archive.phtml?wshow=paper&jrnid=emj&paperid=246&option_lang=rus

Embeddings relations between weighted complementary Local Morrey-type spaces and weighted local Morrey-type spaces

Czech Academy of Sciences Publication Activity Database

Gogatishvili, Amiran; Mustafayev, R.Ch.; Ünver, T.

2017-01-01

Roč. 8, č. 1 (2017), s. 34-49 ISSN 2077-9879 R&D Projects: GA ČR GA13-14743S Institutional support: RVO:67985840 Keywords : local Morrey-type spaces * embeddings * iterated Hardy inequalities Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics http://www.mathnet.ru/php/archive.phtml?wshow=paper&jrnid=emj&paperid=246&option_lang=rus

Optimality of embeddings of Bessel-potential-type spaces into generalized Hölder spaces

Czech Academy of Sciences Publication Activity Database

Gogatishvili, Amiran; Neves, J. S.; Opic, Bohumír

2005-01-01

Roč. 49, č. 2 (2005), s. 297-327 ISSN 0214-1493 R&D Projects: GA ČR(CZ) GA201/01/0333 Institutional research plan: CEZ:AV0Z10190503 Keywords : slowly varying functions * Lorentz-Karamata spaces * (fractional) Sobolev-type spaces Subject RIV: BA - General Mathematics Impact factor: 0.659, year: 2005

Color preferences for four different types of spaces

NARCIS (Netherlands)

van der Voordt, Theo; Bakker, I.C.; de Boon, J

2017-01-01

Purpose: Studies on color preferences for different types of spaces are scarce and show ambiguous results. This paper aims to present data about preferred colors for two work environments: the office and a meeting room, and two residential spaces: the living room and the bedroom. The authors also

Definition of technology development missions for early space stations: Large space structures

Science.gov (United States)

Gates, R. M.; Reid, G.

1984-01-01

The objectives studied are the definition of the tested role of an early Space Station for the construction of large space structures. This is accomplished by defining the LSS technology development missions (TDMs) identified in phase 1. Design and operations trade studies are used to identify the best structural concepts and procedures for each TDMs. Details of the TDM designs are then developed along with their operational requirements. Space Station resources required for each mission, both human and physical, are identified. The costs and development schedules for the TDMs provide an indication of the programs needed to develop these missions.

Sobolev type spaces associated with the q-Rubin's operator

Directory of Open Access Journals (Sweden)

Neji Bettaibi

2014-05-01

Full Text Available In this paper we introduce and   study   some $q$-Sobolev type spaces by using the harmonic analysis associated with the q-Rubin operator. In particular, embedding theorems for these spaces are established.  Next, we introduce the q-Rubin potential spaces and study some of its properties.

Stochastic sampling of the RNA structural alignment space.

Science.gov (United States)

Harmanci, Arif Ozgun; Sharma, Gaurav; Mathews, David H

2009-07-01

A novel method is presented for predicting the common secondary structures and alignment of two homologous RNA sequences by sampling the 'structural alignment' space, i.e. the joint space of their alignments and common secondary structures. The structural alignment space is sampled according to a pseudo-Boltzmann distribution based on a pseudo-free energy change that combines base pairing probabilities from a thermodynamic model and alignment probabilities from a hidden Markov model. By virtue of the implicit comparative analysis between the two sequences, the method offers an improvement over single sequence sampling of the Boltzmann ensemble. A cluster analysis shows that the samples obtained from joint sampling of the structural alignment space cluster more closely than samples generated by the single sequence method. On average, the representative (centroid) structure and alignment of the most populated cluster in the sample of structures and alignments generated by joint sampling are more accurate than single sequence sampling and alignment based on sequence alone, respectively. The 'best' centroid structure that is closest to the known structure among all the centroids is, on average, more accurate than structure predictions of other methods. Additionally, cluster analysis identifies, on average, a few clusters, whose centroids can be presented as alternative candidates. The source code for the proposed method can be downloaded at http://rna.urmc.rochester.edu.

Exploring space-time structure of human mobility in urban space

Science.gov (United States)

Sun, J. B.; Yuan, J.; Wang, Y.; Si, H. B.; Shan, X. M.

2011-03-01

Understanding of human mobility in urban space benefits the planning and provision of municipal facilities and services. Due to the high penetration of cell phones, mobile cellular networks provide information for urban dynamics with a large spatial extent and continuous temporal coverage in comparison with traditional approaches. The original data investigated in this paper were collected by cellular networks in a southern city of China, recording the population distribution by dividing the city into thousands of pixels. The space-time structure of urban dynamics is explored by applying Principal Component Analysis (PCA) to the original data, from temporal and spatial perspectives between which there is a dual relation. Based on the results of the analysis, we have discovered four underlying rules of urban dynamics: low intrinsic dimensionality, three categories of common patterns, dominance of periodic trends, and temporal stability. It implies that the space-time structure can be captured well by remarkably few temporal or spatial predictable periodic patterns, and the structure unearthed by PCA evolves stably over time. All these features play a critical role in the applications of forecasting and anomaly detection.

Determination of a new structure type in the Sc-Fe-Ge-Sn system

Energy Technology Data Exchange (ETDEWEB)

Brgoch, Jakoah [Department of Chemistry, Iowa State University, Ames, IA 50011 (United States); Ran, Sheng [Ames Laboratory, US Department of Energy, Ames, IA 50011 (United States); Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Thimmaiah, Srinivasa [Department of Chemistry, Iowa State University, Ames, IA 50011 (United States); Ames Laboratory, US Department of Energy, Ames, IA 50011 (United States); Canfield, Paul C. [Ames Laboratory, US Department of Energy, Ames, IA 50011 (United States); Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Miller, Gordon J., E-mail: gmiller@iastate.edu [Department of Chemistry, Iowa State University, Ames, IA 50011 (United States); Ames Laboratory, US Department of Energy, Ames, IA 50011 (United States)

2013-01-05

Highlights: Black-Right-Pointing-Pointer A new structure type with the composition Sc{sub 4}Fe{sub 5}Ge{sub 6.10(3)}Sn{sub 1.47(2)}. Black-Right-Pointing-Pointer Crystallizes in the space group Immm (No. 71, oI144). Black-Right-Pointing-Pointer Sample obtained using a reactive Sn flux. Black-Right-Pointing-Pointer Electronic structure calculations indicate polar intermetallic bonding network. - Abstract: A new structure type has been discovered in the system Sc-Fe-Ge-Sn by employing Sn as a flux medium. According to single crystal X-ray diffraction, the new structure has a composition of Sc{sub 4}Fe{sub 5}Ge{sub 6.10(3)}Sn{sub 1.47(2)} and crystallizes in the space group Immm (No. 71, oI144) with lattice parameters of a = 5.230(1) A, b = 13.467(3) A, and c = 30.003(6) A. The structure is composed of square anti-prismatic clusters that are condensed into zig-zag chains along the [0 1 0] direction. These chains are further condensed through a split Sn/Ge position, forming a three-dimensional network. Magnetization measurements indicate an antiferromagnetic phase transition near 240 K. Electronic structure calculations identified the most favorable bonding network in this new system. Using crystal orbital Hamilton population (COHP) curves and their integrated values (ICOHP), a polar intermetallic bonding network involving Sc-Ge as well as Fe-Sn and Fe-Ge contacts can be assigned to this new structure type.

Definition of technology development missions for early space stations. Large space structures, phase 2, midterm review

Science.gov (United States)

1984-01-01

The large space structures technology development missions to be performed on an early manned space station was studied and defined and the resources needed and the design implications to an early space station to carry out these large space structures technology development missions were determined. Emphasis is being placed on more detail in mission designs and space station resource requirements.

Structural damage detection-oriented multi-type sensor placement with multi-objective optimization

Science.gov (United States)

Lin, Jian-Fu; Xu, You-Lin; Law, Siu-Seong

2018-05-01

A structural damage detection-oriented multi-type sensor placement method with multi-objective optimization is developed in this study. The multi-type response covariance sensitivity-based damage detection method is first introduced. Two objective functions for optimal sensor placement are then introduced in terms of the response covariance sensitivity and the response independence. The multi-objective optimization problem is formed by using the two objective functions, and the non-dominated sorting genetic algorithm (NSGA)-II is adopted to find the solution for the optimal multi-type sensor placement to achieve the best structural damage detection. The proposed method is finally applied to a nine-bay three-dimensional frame structure. Numerical results show that the optimal multi-type sensor placement determined by the proposed method can avoid redundant sensors and provide satisfactory results for structural damage detection. The restriction on the number of each type of sensors in the optimization can reduce the searching space in the optimization to make the proposed method more effective. Moreover, how to select a most optimal sensor placement from the Pareto solutions via the utility function and the knee point method is demonstrated in the case study.

Mechanical properties of different types of space maintainers

Science.gov (United States)

Beldiman, M.-A.; Mârţu, I.; Leiţoiu, B.; Luchian, I.; Lupescu, O.; Bârcă, E. S.

2015-11-01

Currently, inside the oral cavity, the dental space maintainers are subjected to forces exerted on them when performing various functions; therefore, it is important to know how each of these mechanisms behave and respond to forces that are applied directly to them. The mechanical properties of the materials used in dentistry are defined by a set of characteristics representing the behaviour of their particular working conditions and it is qualitatively expressed by a number of parameters.The study aimed to determine the pressing force that can be taken by four 4 types of space maintainers frequently used in practice - fixed and removable, applied on four samples realized with human teeth extracted for orthodontic purposes. Static tests were carried out on a machine type short WDW-5 EC with a maximum force of 5 kN and a loading speed of 5 mm/min by a special testing machine, with an innovative appliance; data recording was automatically performed, using a computer with a special program that present the specific diagrams. Experimental determinations included the following aspects: to determine the maximum force that can be supported by each sample, and to observe the deformations. The values obtained indicate that the best option in terms of behavior under the conditions specified is the removable appliance, and the less functional version is the fixed space maintainer using brackets. According to tests conducted, the fracture strength was found to be more important for fixed space maintainers (band and loop, for example) so, in practice is using more frequent these types of space maintainers.

Carbon composites in space vehicle structures

Science.gov (United States)

Mayer, N. J.

1974-01-01

Recent developments in the technology of carbon or graphite filaments now provide the designer with greatly improved materials offering high specific strength and modulus. Besides these advantages are properties which are distinctly useful for space applications and which provide feasibility for missions not obtainable by other means. Current applications include major and secondary structures of communications satellites. A number of R & D projects are exploring carbon-fiber application to rocket engine motor cases, advanced antenna systems, and space shuttle components. Future system studies are being made, based on the successful application of carbon fibers for orbiting space telescope assemblies, orbital transfer vehicles, and very large deployable energy generation systems. Continued technology development is needed in analysis, material standards, and advanced structural concepts to exploit the full potential of carbon filaments in composite materials.

On the phase space structure of IP3 induced Ca2+ signalling and concepts for predictive modeling

Science.gov (United States)

Falcke, Martin; Moein, Mahsa; TilÅ«naitÄ--, Agne; Thul, Rüdiger; Skupin, Alexander

2018-04-01

The correspondence between mathematical structures and experimental systems is the basis of the generalizability of results found with specific systems and is the basis of the predictive power of theoretical physics. While physicists have confidence in this correspondence, it is less recognized in cellular biophysics. On the one hand, the complex organization of cellular dynamics involving a plethora of interacting molecules and the basic observation of cell variability seem to question its possibility. The practical difficulties of deriving the equations describing cellular behaviour from first principles support these doubts. On the other hand, ignoring such a correspondence would severely limit the possibility of predictive quantitative theory in biophysics. Additionally, the existence of functional modules (like pathways) across cell types suggests also the existence of mathematical structures with comparable universality. Only a few cellular systems have been sufficiently investigated in a variety of cell types to follow up these basic questions. IP3 induced Ca2+signalling is one of them, and the mathematical structure corresponding to it is subject of ongoing discussion. We review the system's general properties observed in a variety of cell types. They are captured by a reaction diffusion system. We discuss the phase space structure of its local dynamics. The spiking regime corresponds to noisy excitability. Models focussing on different aspects can be derived starting from this phase space structure. We discuss how the initial assumptions on the set of stochastic variables and phase space structure shape the predictions of parameter dependencies of the mathematical models resulting from the derivation.

Dynamics of Structures in Configuration Space and Phase Space: An Introductory Tutorial

Science.gov (United States)

Diamond, P. H.; Kosuga, Y.; Lesur, M.

2015-12-01

Some basic ideas relevant to the dynamics of phase space and real space structures are presented in a pedagogical fashion. We focus on three paradigmatic examples, namely; G. I. Taylor's structure based re-formulation of Rayleigh's stability criterion and its implications for zonal flow momentum balance relations; Dupree's mechanism for nonlinear current driven ion acoustic instability and its implication for anomalous resistivity; and the dynamics of structures in drift and gyrokinetic turbulence and their relation to zonal flow physics. We briefly survey the extension of mean field theory to calculate evolution in the presence of localized structures for regimes where Kubo number K ≃ 1 rather than K ≪ 1, as is usual for quasilinear theory.

Study of static properties of magnetron-type space charges

International Nuclear Information System (INIS)

Delcroix, Jean-Loup

1953-01-01

This research thesis reports an in-depth analysis of physical properties of static regimes to address the issue of space charges. This theoretical study of the Hull magnetron is followed by the description of experiments on the Hull magnetron which highlight transitions between the different regimes. Then, another theoretical approach aims at generalising the magnetron theory, based on other types of magnetron theory (general equations of magnetron-type space charges, inverted Hull magnetron theory, circular field magnetron theory)

A scale invariant covariance structure on jet space

DEFF Research Database (Denmark)

Pedersen, Kim Steenstrup; Loog, Marco; Markussen, Bo

2005-01-01

This paper considers scale invariance of statistical image models. We study statistical scale invariance of the covariance structure of jet space under scale space blurring and derive the necessary structure and conditions of the jet covariance matrix in order for it to be scale invariant. As par...

Space platform expendables resupply concept definition study. Volume 3: Work breakdown structure and work breakdown structure dictionary

Science.gov (United States)

1984-01-01

The work breakdown structure (WBS) for the Space Platform Expendables Resupply Concept Definition Study is described. The WBS consists of a list of WBS elements, a dictionary of element definitions, and an element logic diagram. The list and logic diagram identify the interrelationships of the elements. The dictionary defines the types of work that may be represented by or be classified under each specific element. The Space Platform Expendable Resupply WBS was selected mainly to support the program planning, scheduling, and costing performed in the programmatics task (task 3). The WBS is neither a statement-of-work nor a work authorization document. Rather, it is a framework around which to define requirements, plan effort, assign responsibilities, allocate and control resources, and report progress, expenditures, technical performance, and schedule performance. The WBS element definitions are independent of make-or-buy decisions, organizational structure, and activity locations unless exceptions are specifically stated.

Presic-Boyd-Wong Type Results in Ordered Metric Spaces

Directory of Open Access Journals (Sweden)

Satish Shukla

2014-04-01

Full Text Available The purpose of this paper is to prove some Presic-Boyd-Wong type fixed point theorems in ordered metric spaces. The results of this paper generalize the famous results of Presic and Boyd-Wong in ordered metric spaces. We also initiate the homotopy result in product spaces. Some examples are provided which illustrate the results proved herein.

Ultra-Lightweight Nanocomposite Foams and Sandwich Structures for Space Structures Applications, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Space structures that are ultra-lightweight, and have gas barrier property, space durability, radiation resistance, EMI shielding, and high impact resistance are...

Ultra-Lightweight Nanocomposite Foams and Sandwich Structures for Space Structures Applications, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Space structures that are ultra-lightweight, and have gas barrier property, space durability, radiation resistance and high impact resistance are desirable to...

Materials and design concepts for space-resilient structures

Science.gov (United States)

Naser, Mohannad Z.; Chehab, Alaa I.

2018-04-01

Space exploration and terraforming nearby planets have been fascinating concepts for the longest time. Nowadays, that technological advancements with regard to space exploration are thriving, it is only a matter of time before humans can start colonizing nearby moons and planets. This paper presents a state-of-the-art literature review on recent developments of "space-native" construction materials, and highlights evolutionary design concepts for "space-resilient" structures (i.e., colonies and habitats). This paper also details effects of harsh (and unique) space environments on various terrestrial and extraterrestrial construction materials, as well as on space infrastructure and structural systems. The feasibility of exploiting available space resources in terms of "in-situ resource utilization" and "harvesting of elements and compounds", as well as emergence of enabling technologies such as "cultured (lab-grown)" space construction materials are discussed. Towards the end of the present review, number of limitations and challenges facing Lunar and Martian exploration, and venues in-need for urgent research are identified and examined.

On the structure of physical space

CERN Document Server

Wisnivesky, D

2001-01-01

In this paper we develop a theory based on the postulate that the environment where physical phenomena take place is the space of four complex parameters of the linear group of transformations. Using these parameters as fundamental building blocks we construct ordinary space-time and the internal space. Lorentz invariance is built in the definition of external space, while the symmetry of the internal space, S(1)*SU(2) results as a consequence of the identification of the external coordinates. Thus, special relativity and the electroweak interaction symmetry ensue from the properties of the basic building blocks of physical space. Since internal and external space are derived from a common structure, there is no need to bring into the theory any additional hypothesis to account for the microscopic nature of the internal space, nor to introduce symmetry breaking mechanisms that would normally be required to force a splitting of the internal and external symmetries. As an outcome of the existence of a basic str...

Weighted inequalities for fractional integral operators and linear commutators in the Morrey-type spaces

Directory of Open Access Journals (Sweden)

Hua Wang

2017-01-01

Full Text Available Abstract In this paper, we first introduce some new Morrey-type spaces containing generalized Morrey space and weighted Morrey space with two weights as special cases. Then we give the weighted strong type and weak type estimates for fractional integral operators I α $I_{\\alpha}$ in these new Morrey-type spaces. Furthermore, the weighted strong type estimate and endpoint estimate of linear commutators [ b , I α ] $[b,I_{\\alpha}]$ formed by b and I α $I_{\\alpha}$ are established. Also we study related problems about two-weight, weak type inequalities for I α $I_{\\alpha}$ and [ b , I α ] $[b,I_{\\alpha}]$ in the Morrey-type spaces and give partial results.

Mapping Spaces, Centralizers, and p-Local Finite Groups of Lie Type

DEFF Research Database (Denmark)

Laude, Isabelle

We study the space of maps from the classifying space of a finite p-group to theBorel construction of a finite group of Lie type G in characteristic p acting on itsbuilding. The first main result is a description of the homology with Fp-coefficients,showing that the mapping space, up to p...... between a finite p-group and theuncompleted classifying space of the p-local finite group coming from a finite groupof Lie type in characteristic p, providing some of the first results in this uncompletedsetting.......-completion, is a disjoint union indexedover the group homomorphism up to conjugation of classifying spaces of centralizersof p-subgroups in the underlying group G. We complement this description bydetermining the actual homotopy groups of the mapping space. These resultstranslate to descriptions of the space of maps...

Effect of Urban Green Spaces and Flooded Area Type on Flooding Probability

Directory of Open Access Journals (Sweden)

Hyomin Kim

2016-01-01

Full Text Available Countermeasures to urban flooding should consider long-term perspectives, because climate change impacts are unpredictable and complex. Urban green spaces have emerged as a potential option to reduce urban flood risks, and their effectiveness has been highlighted in notable urban water management studies. In this study, flooded areas in Seoul, Korea, were divided into four flooded area types by cluster analysis based on topographic and physical characteristics and verified using discriminant analysis. After division by flooded area type, logistic regression analysis was performed to determine how the flooding probability changes with variations in green space area. Type 1 included regions where flooding occurred in a drainage basin that had a flood risk management infrastructure (FRMI. In Type 2, the slope was steep; the TWI (Topographic Wetness Index was relatively low; and soil drainage was favorable. Type 3 represented the gentlest sloping areas, and these were associated with the highest TWI values. In addition, these areas had the worst soil drainage. Type 4 had moderate slopes, imperfect soil drainage and lower than average TWI values. We found that green spaces exerted a considerable influence on urban flooding probabilities in Seoul, and flooding probabilities could be reduced by over 50% depending on the green space area and the locations where green spaces were introduced. Increasing the area of green spaces was the most effective method of decreasing flooding probability in Type 3 areas. In Type 2 areas, the maximum hourly precipitation affected the flooding probability significantly, and the flooding probability in these areas was high despite the extensive green space area. These findings can contribute towards establishing guidelines for urban spatial planning to respond to urban flooding.

Compound Structure-Independent Activity Prediction in High-Dimensional Target Space.

Science.gov (United States)

Balfer, Jenny; Hu, Ye; Bajorath, Jürgen

2014-08-01

Profiling of compound libraries against arrays of targets has become an important approach in pharmaceutical research. The prediction of multi-target compound activities also represents an attractive task for machine learning with potential for drug discovery applications. Herein, we have explored activity prediction in high-dimensional target space. Different types of models were derived to predict multi-target activities. The models included naïve Bayesian (NB) and support vector machine (SVM) classifiers based upon compound structure information and NB models derived on the basis of activity profiles, without considering compound structure. Because the latter approach can be applied to incomplete training data and principally depends on the feature independence assumption, SVM modeling was not applicable in this case. Furthermore, iterative hybrid NB models making use of both activity profiles and compound structure information were built. In high-dimensional target space, NB models utilizing activity profile data were found to yield more accurate activity predictions than structure-based NB and SVM models or hybrid models. An in-depth analysis of activity profile-based models revealed the presence of correlation effects across different targets and rationalized prediction accuracy. Taken together, the results indicate that activity profile information can be effectively used to predict the activity of test compounds against novel targets. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimum Design of Braced Steel Space Frames including Soil-Structure Interaction via Teaching-Learning-Based Optimization and Harmony Search Algorithms

OpenAIRE

Ayse T. Daloglu; Musa Artar; Korhan Ozgan; Ali İ. Karakas

2018-01-01

Optimum design of braced steel space frames including soil-structure interaction is studied by using harmony search (HS) and teaching-learning-based optimization (TLBO) algorithms. A three-parameter elastic foundation model is used to incorporate the soil-structure interaction effect. A 10-storey braced steel space frame example taken from literature is investigated according to four different bracing types for the cases with/without soil-structure interaction. X, V, Z, and eccentric V-shaped...

Space-Time Crystal and Space-Time Group.

Science.gov (United States)

Xu, Shenglong; Wu, Congjun

2018-03-02

Crystal structures and the Bloch theorem play a fundamental role in condensed matter physics. We extend the static crystal to the dynamic "space-time" crystal characterized by the general intertwined space-time periodicities in D+1 dimensions, which include both the static crystal and the Floquet crystal as special cases. A new group structure dubbed a "space-time" group is constructed to describe the discrete symmetries of a space-time crystal. Compared to space and magnetic groups, the space-time group is augmented by "time-screw" rotations and "time-glide" reflections involving fractional translations along the time direction. A complete classification of the 13 space-time groups in one-plus-one dimensions (1+1D) is performed. The Kramers-type degeneracy can arise from the glide time-reversal symmetry without the half-integer spinor structure, which constrains the winding number patterns of spectral dispersions. In 2+1D, nonsymmorphic space-time symmetries enforce spectral degeneracies, leading to protected Floquet semimetal states. We provide a general framework for further studying topological properties of the (D+1)-dimensional space-time crystal.

Fractional type Marcinkiewicz integrals over non-homogeneous metric measure spaces

Directory of Open Access Journals (Sweden)

Guanghui Lu

2016-10-01

Full Text Available Abstract The main goal of the paper is to establish the boundedness of the fractional type Marcinkiewicz integral M β , ρ , q $\\mathcal{M}_{\\beta,\\rho,q}$ on non-homogeneous metric measure space which includes the upper doubling and the geometrically doubling conditions. Under the assumption that the kernel satisfies a certain Hörmander-type condition, the authors prove that M β , ρ , q $\\mathcal{M}_{\\beta,\\rho,q}$ is bounded from Lebesgue space L 1 ( μ $L^{1}(\\mu$ into the weak Lebesgue space L 1 , ∞ ( μ $L^{1,\\infty}(\\mu$ , from the Lebesgue space L ∞ ( μ $L^{\\infty}(\\mu$ into the space RBLO ( μ $\\operatorname{RBLO}(\\mu$ , and from the atomic Hardy space H 1 ( μ $H^{1}(\\mu$ into the Lebesgue space L 1 ( μ $L^{1}(\\mu$ . Moreover, the authors also get a corollary, that is, M β , ρ , q $\\mathcal{M}_{\\beta,\\rho,q}$ is bounded on L p ( μ $L^{p}(\\mu$ with 1 < p < ∞ $1< p<\\infty$ .

Assessing the Associations Between Types of Green Space, Physical Activity, and Health Indicators Using GIS and Participatory Survey

Science.gov (United States)

Akpinar, A.

2017-11-01

This study explores whether specific types of green spaces (i.e. urban green spaces, forests, agricultural lands, rangelands, and wetlands) are associated with physical activity, quality of life, and cardiovascular disease prevalence. A sample of 8,976 respondents from the Behavioral Risk Factor Surveillance System, conducted in 2006 in Washington State across 291 zip-codes, was analyzed. Measures included physical activity status, quality of life, and cardiovascular disease prevalence (i.e. heart attack, angina, and stroke). Percentage of green spaces was derived from the National Land Cover Dataset and measured with Geographical Information System. Multilevel regression analyses were conducted to analyze the data while controlling for age, sex, race, weight, marital status, occupation, income, education level, and zip-code population and socio-economic situation. Regression results reveal that no green space types were associated with physical activity, quality of life, and cardiovascular disease prevalence. On the other hand, the analysis shows that physical activity was associated with general health, quality of life, and cardiovascular disease prevalence. The findings suggest that other factors such as size, structure and distribution (sprawled or concentrated, large or small), quality, and characteristics of green space might be important in general health, quality of life, and cardiovascular disease prevalence rather than green space types. Therefore, further investigations are needed.

In silico approaches and chemical space of anti-P-type ATPase compounds for discovering new antituberculous drugs.

Science.gov (United States)

Santos, Paola; López-Vallejo, Fabian; Soto, Carlos-Y

2017-08-01

Tuberculosis (TB) is one of the most important public health problems around the world. The emergence of multi-drug-resistant (MDR) and extensively drug-resistant (XDR) Mycobacterium tuberculosis strains has driven the finding of alternative anti-TB targets. In this context, P-type ATPases are interesting therapeutic targets due to their key role in ion homeostasis across the plasma membrane and the mycobacterial survival inside macrophages. In this review, in silico and experimental strategies used for the rational design of new anti-TB drugs are presented; in addition, the chemical space distribution based on the structure and molecular properties of compounds with anti-TB and anti-P-type ATPase activity is discussed. The chemical space distribution compared to public compound libraries demonstrates that natural product libraries are a source of novel chemical scaffolds with potential anti-P-type ATPase activity. Furthermore, compounds that experimentally display anti-P-type ATPase activity belong to a chemical space of molecular properties comparable to that occupied by those approved for oral use, suggesting that these kinds of molecules have a good pharmacokinetic profile (drug-like) for evaluation as potential anti-TB drugs. © 2017 John Wiley & Sons A/S.

Significance of structure–soil–structure interaction for closely spaced structures

International Nuclear Information System (INIS)

Roy, Christine; Bolourchi, Said; Eggers, Daniel

2015-01-01

Nuclear facilities typically consist of many closely spaced structures with different sizes and depths of embedment. Seismic response of each structure could be influenced by dynamic structure–soil–structure interaction (SSSI) behavior of adjacent closely spaced structures. This paper examines the impact of SSSI on the in-structure response spectra (ISRS) and peak accelerations of a light structure adjacent to a heavy structure and of a heavy structure adjacent to a similar heavy structure for several soil cases, foundation embedment depths, and separation distances. The impacts of a heavy surface or embedded structure on adjacent ground motions were studied. The analyses demonstrated the adjacent ground motions are sensitive to foundation embedment, soil profile, response frequency, and distance from the structure. Seismic responses of a light structure located near a heavy structure are calculated either by modeling both structures subjected to free field motions, or performing a cascade analysis by considering the light structure model subjected to modified ground motions due to the heavy structure. Cascade SSSI analyses are shown to adequately account for the effect of the heavy structure on the light structure without explicitly modeling both structures together in a single analysis. To further study the influence of SSSI behavior, this paper examines dynamic response of two adjacent heavy structures and compares this response to response of a single heavy structure neglecting adjacent structures. The SSSI responses of the two heavy structures are evaluated for varying soil conditions and structure separation distances using three-dimensional linear SSI analyses and considering anti-symmetry boundary conditions. The analyses demonstrate that the SSSI response of a light or a heavy structure can be influenced by the presence of a nearby heavy structure. Although this study considers linear analysis methodology, the conclusion of SSSI influences on dynamic

On an Integral-Type Operator Acting between Bloch-Type Spaces on the Unit Ball

Directory of Open Access Journals (Sweden)

Stevo Stević

2010-01-01

Full Text Available Let 𝔹 denote the open unit ball of ℂn. For a holomorphic self-map φ of 𝔹 and a holomorphic function g in 𝔹 with g(0=0, we define the following integral-type operator: Iφgf(z=∫01ℜf(φ(tzg(tz(dt/t, z∈𝔹. Here ℜf denotes the radial derivative of a holomorphic function f in 𝔹. We study the boundedness and compactness of the operator between Bloch-type spaces ℬω and ℬμ, where ω is a normal weight function and μ is a weight function. Also we consider the operator between the little Bloch-type spaces ℬω,0 and ℬμ,0.

Momentum-Space Imaging of the Dirac Band Structure in Molecular Graphene via Quasiparticle Interference

Science.gov (United States)

Stephenson, Anna; Gomes, Kenjiro K.; Ko, Wonhee; Mar, Warren; Manoharan, Hari C.

2014-03-01

Molecular graphene is a nanoscale artificial lattice composed of carbon monoxide molecules arranged one by one, realizing a dream of exploring exotic quantum materials by design. This assembly is done by atomic manipulation with a scanning tunneling microscope (STM) on a Cu(111) surface. To directly probe the transformation of normal surface state electrons into massless Dirac fermions, we map the momentum space dispersion through the Fourier analysis of quasiparticle scattering maps acquired at different energies with the STM. The Fourier analysis not only bridges the real-space and momentum-space data but also reveals the chiral nature of those quasiparticles, through a set of selection rules of allowed scattering involving the pseudospin and valley degrees of freedom. The graphene-like band structure can be reshaped with simple alterations to the lattice, such as the addition of a strain. We analyze the effect on the momentum space band structure of multiple types of strain on our system. Supported by DOE, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering under contract DE-AC02-76SF00515.

Space Transportation Materials and Structures Technology Workshop. Volume 2: Proceedings

International Nuclear Information System (INIS)

Cazier, F.W. Jr.; Gardner, J.E.

1993-02-01

The Space Transportation Materials and Structures Technology Workshop was held on September 23-26, 1991, in Newport News, Virginia. The workshop, sponsored by the NASA Office of Space Flight and the NASA Office of Aeronautics and Space Technology, was held to provide a forum for communication within the space materials and structures technology developer and user communities. Workshop participants were organized into a Vehicle Technology Requirements session and three working panels: Materials and Structures Technologies for Vehicle Systems, Propulsion Systems, and Entry Systems. Separate abstracts have been prepared for papers in this report

Mach's principle and space-time structure

International Nuclear Information System (INIS)

Raine, D.J.

1981-01-01

Mach's principle, that inertial forces should be generated by the motion of a body relative to the bulk of matter in the universe, is shown to be related to the structure imposed on space-time by dynamical theories. General relativity theory and Mach's principle are both shown to be well supported by observations. Since Mach's principle is not contained in general relativity this leads to a discussion of attempts to derive Machian theories. The most promising of these appears to be a selection rule for solutions of the general relativistic field equations, in which the space-time metric structure is generated by the matter content of the universe only in a well-defined way. (author)

Optimum Design of Braced Steel Space Frames including Soil-Structure Interaction via Teaching-Learning-Based Optimization and Harmony Search Algorithms

Directory of Open Access Journals (Sweden)

Ayse T. Daloglu

2018-01-01

Full Text Available Optimum design of braced steel space frames including soil-structure interaction is studied by using harmony search (HS and teaching-learning-based optimization (TLBO algorithms. A three-parameter elastic foundation model is used to incorporate the soil-structure interaction effect. A 10-storey braced steel space frame example taken from literature is investigated according to four different bracing types for the cases with/without soil-structure interaction. X, V, Z, and eccentric V-shaped bracing types are considered in the study. Optimum solutions of examples are carried out by a computer program coded in MATLAB interacting with SAP2000-OAPI for two-way data exchange. The stress constraints according to AISC-ASD (American Institute of Steel Construction-Allowable Stress Design, maximum lateral displacement constraints, interstorey drift constraints, and beam-to-column connection constraints are taken into consideration in the optimum design process. The parameters of the foundation model are calculated depending on soil surface displacements by using an iterative approach. The results obtained in the study show that bracing types and soil-structure interaction play very important roles in the optimum design of steel space frames. Finally, the techniques used in the optimum design seem to be quite suitable for practical applications.

ASSESSING THE ASSOCIATIONS BETWEEN TYPES OF GREEN SPACE, PHYSICAL ACTIVITY, AND HEALTH INDICATORS USING GIS AND PARTICIPATORY SURVEY

Directory of Open Access Journals (Sweden)

A. Akpinar

2017-11-01

Full Text Available This study explores whether specific types of green spaces (i.e. urban green spaces, forests, agricultural lands, rangelands, and wetlands are associated with physical activity, quality of life, and cardiovascular disease prevalence. A sample of 8,976 respondents from the Behavioral Risk Factor Surveillance System, conducted in 2006 in Washington State across 291 zip-codes, was analyzed. Measures included physical activity status, quality of life, and cardiovascular disease prevalence (i.e. heart attack, angina, and stroke. Percentage of green spaces was derived from the National Land Cover Dataset and measured with Geographical Information System. Multilevel regression analyses were conducted to analyze the data while controlling for age, sex, race, weight, marital status, occupation, income, education level, and zip-code population and socio-economic situation. Regression results reveal that no green space types were associated with physical activity, quality of life, and cardiovascular disease prevalence. On the other hand, the analysis shows that physical activity was associated with general health, quality of life, and cardiovascular disease prevalence. The findings suggest that other factors such as size, structure and distribution (sprawled or concentrated, large or small, quality, and characteristics of green space might be important in general health, quality of life, and cardiovascular disease prevalence rather than green space types. Therefore, further investigations are needed.

Probabilistic structural analysis methods for space transportation propulsion systems

Science.gov (United States)

Chamis, C. C.; Moore, N.; Anis, C.; Newell, J.; Nagpal, V.; Singhal, S.

1991-01-01

Information on probabilistic structural analysis methods for space propulsion systems is given in viewgraph form. Information is given on deterministic certification methods, probability of failure, component response analysis, stress responses for 2nd stage turbine blades, Space Shuttle Main Engine (SSME) structural durability, and program plans. .

Environmental Disturbance Modeling for Large Inflatable Space Structures

National Research Council Canada - National Science Library

Davis, Donald

2001-01-01

Tightening space budgets and stagnating spacelift capabilities are driving the Air Force and other space agencies to focus on inflatable technology as a reliable, inexpensive means of deploying large structures in orbit...

Geodesics in Goedel-type space-times

International Nuclear Information System (INIS)

Calvao, M.O.; Soares, I.D.; Tiomno, J.

1988-01-01

The geodesic curves of the homogeneous Goedel-type space-times, which constitute a two-parameter ({ l and Ω}) class of solutions presented to several theories of gravitation (general relativity, Einstein-Cartan and higher derivative) are investigated. The qualitative properties of those curves by means of the introduction of an effective potential and then accomplish the analytical integration of the equations of motion are examined. It is shown that some of the qualitative features of the free motion in Godel's universe (l 2 =2Ω 2 ) are preserved in all space-times, namely the projections of the geodesics onto the 2-surface (r,ψ) are simple closed curves, and the geodesics for which the ratio of azymuthal angular momentum to total energy, υ is equal to zero always cross the origin r = o. However, two new cases appear: (i) radially unbounded geodesics with υ assuming any (real) value, which may occur only for the causal space-times (l 2 ≥ 4 Ω 2 ), and (ii) geodesics with υ bounded both below and above, which always occur for the circular family (l 2 [pt

Fourier Multipliers on Decomposition Spaces of Modulation and Triebel–Lizorkin Type

DEFF Research Database (Denmark)

Cleanthous, G.; Georgiadis, Athanasios; Nielsen, Morten

2018-01-01

spaces in both the isotropic and an anisotropic setting. We derive a boundedness result for Fourier multipliers on anisotropic decomposition spaces of modulation and Triebel–Lizorkin type. As an application, we obtain equivalent quasi-norm characterizations for this class of decomposition spaces....

11th International Space Conference on Protection of Materials and Structures from Space Environment

CERN Document Server

2017-01-01

The proceedings published in this book document and foster the goals of the 11th International Space Conference on “Protection of Materials and Structures from Space Environment” ICPMSE-11 to facilitate exchanges between members of the various engineering and science disciplines involved in the development of space materials. Contributions cover aspects of interaction with space environment of LEO, GEO, Deep Space, Planetary environments, ground-based qualification and in-flight experiments, as well as lessons learned from operational vehicles that are closely interrelated to disciplines of atmospheric sciences, solar-terrestrial interactions and space life sciences.

Modeling, Analysis, and Optimization Issues for Large Space Structures

Science.gov (United States)

Pinson, L. D. (Compiler); Amos, A. K. (Compiler); Venkayya, V. B. (Compiler)

1983-01-01

Topics concerning the modeling, analysis, and optimization of large space structures are discussed including structure-control interaction, structural and structural dynamics modeling, thermal analysis, testing, and design.

Synthesis, structural, spectroscopic and thermoanalytical study of sol–gel derived SiO{sub 2}–CaO–P{sub 2}O{sub 5} gel and ceramic materials

Energy Technology Data Exchange (ETDEWEB)

Catauro, Michelina, E-mail: michelina.catauro@unina2.it [Department of Industrial and Information Engineering, Second University of Naples, via Roma 29, Aversa (CE) (Italy); Dell’Era, Alessandro [Department D.M.E., ‘Guglielmo Marconi’ University, via Plinio 44, Roma (Italy); Vecchio Ciprioti, Stefano, E-mail: stefano.vecchio@uniroma1.it [Department S.B.A.I., Sapienza University of Rome, via del Castro Laurenziano 7, Roma (Italy)

2016-02-10

Highlights: • Four different SiO{sub 2}–CaO–P{sub 2}O{sub 5} gel-glasses were synthesized by the sol–gel method. • FTIR, XRD, SEM-EDS and TG/DTA techniques were used to fully characterize the gels. • Integral isoconversional OFW method was used to study dehydration kinetics. • Appropriate temperatures of 600 and 1200 °C were chosen to thermally treat them. • All amorphous gels at 1200 °C crystallize as wollastonite and pseudowollastonite. - Abstract: In the present work bioactive powders of the ternary SiO{sub 2}·CaO·P{sub 2}O{sub 5} systems, which differ in the Ca/P molar ratio, were synthesized by means of a sol–gel route, using tetraethyl orthosilicate (TEOS, Si(OC{sub 2}H{sub 5}){sub 4}), calcium nitrate tetrahydrate (Ca(NO{sub 3}){sub 2}·4H{sub 2}O) and triethyl phosphate (TEP, OP(OC{sub 2}H{sub 5}){sub 3}) as precursors of SiO{sub 2}, CaO and P{sub 2}O{sub 5}, respectively. In order to investigate the influence of the relative amount of each phase (in this study: SiO{sub 2}, CaO and P{sub 2}O{sub 5}) the thermal properties of the synthesized gel-glass materials were studied as a function of the Ca/P molar ratio using thermogravimetric and differential thermal analysis (TG/DTA). After dehydration (in a single step), described from a kinetic point of view as a simple water evaporation without rupture of chemical bonds, all gels undergo a complex multi-step decomposition with endo and exothermic effects, followed by crystallization of calcium silicate phases at about 950 °C. Furthermore, Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD) and Scanning Electron Microscopy, coupled with energy dispersive spectroscopy (SEM/EDS), allowed us to detect the chemical modifications induced by modifying the Ca/P molar ratio and the sintering. This process is obtained by thermal treatment of the gel-glass precursors after analyzing their thermal behavior in the temperature range 600–1000 °C, with the aim to convert them into

On Λ-Type Duality of Frames in Banach Spaces

Directory of Open Access Journals (Sweden)

Renu Chugh

2013-11-01

Full Text Available Frames are redundant system which are useful in the reconstruction of certain classes of spaces. The dual of a frame (Hilbert always exists and can be obtained in a natural way. Due to the presence of three Banach spaces in the definition of retro Banach frames (or Banach frames duality of frames in Banach spaces is not similar to frames for Hilbert spaces. In this paper we introduce the notion of Λ-type duality of retro Banach frames. This can be generalized to Banach frames in Banach spaces. Necessary and sufficient conditions for the existence of the dual of retro Banach frames are obtained. A special class of retro Banach frames which always admit a dual frame is discussed.

Atomic fine structure in a space of constant curvature

International Nuclear Information System (INIS)

Bessis, N.; Bessis, G.; Shamseddine, R.

1982-01-01

As a contribution to a tentative formulation of atomic physics in a curved space, the determination of atomic fine structure energies in a space of constant curvature is investigated. Starting from the Dirac equation in a curved space-time, the analogue of the Pauli equation in a general coordinate system is derived. The theoretical curvature induced shifts and splittings of the fine structure energy levels are put in evidence and examined for the particular case of the hydrogenic n=2 levels. (author)

Space Fission Reactor Structural Materials: Choices Past, Present and Future

International Nuclear Information System (INIS)

Busby, Jeremy T.; Leonard, Keith J.

2007-01-01

Nuclear powered spacecraft will enable missions well beyond the capabilities of current chemical, radioisotope thermal generator and solar technologies. The use of fission reactors for space applications has been considered for over 50 years, although, structural material performance has often limited the potential performance of space reactors. Space fission reactors are an extremely harsh environment for structural materials with high temperatures, high neutron fields, potential contact with liquid metals, and the need for up to 15-20 year reliability with no inspection or preventative maintenance. Many different materials have been proposed as structural materials. While all materials meet many of the requirements for space reactor service, none satisfy all of them. However, continued development and testing may resolve these issues and provide qualified materials for space fission reactors.

Periodic orbits and TDHF phase space structure

Energy Technology Data Exchange (ETDEWEB)

Hashimoto, Yukio; Iwasawa, Kazuo [Tsukuba Univ., Ibaraki (Japan). Inst. of Physics; Tsukuma, Hidehiko; Sakata, Fumihiko

1998-03-01

The collective motion of atomic nuclei is closely coupled with the motion of nucleons, therefore, it is nonlinear, and the contents of the motion change largely with the increase of its amplitude. As the framework which describes the collective motion accompanied by the change of internal structure, time-dependent Hurtley Fock (TDHF) method is suitable. At present, the authors try to make the method for studying the large region structure in quantum system by utilizing the features of the TDHF phase space. The studies made so far are briefed. In this report, the correspondence of the large region patterns appearing in the band structure chart of three-level model with the periodic orbit group in the TDHF phase space is described. The Husimi function is made, and it possesses the information on the form of respective corresponding intrinsic state. The method of making the band structure chart is explained. There are three kinds of the tendency in the intrinsic state group. The E-T charts are made for the band structure charts to quantitatively express the large region tendency. The E-T chart and the T{sub r}-T chart are drawn for a selected characteristic orbit group. It became to be known that the large region properties of the quantum intrinsic state group of three-level model can be forecast by examining the properties of the periodic orbit group in the TDHF phase space. (K.I.)

Efficient placement of structural dynamics sensors on the space station

Science.gov (United States)

Lepanto, Janet A.; Shepard, G. Dudley

1987-01-01

System identification of the space station dynamic model will require flight data from a finite number of judiciously placed sensors on it. The placement of structural dynamics sensors on the space station is a particularly challenging problem because the station will not be deployed in a single mission. Given that the build-up sequence and the final configuration for the space station are currently undetermined, a procedure for sensor placement was developed using the assembly flights 1 to 7 of the rephased dual keel space station as an example. The procedure presented approaches the problem of placing the sensors from an engineering, as opposed to a mathematical, point of view. In addition to locating a finite number of sensors, the procedure addresses the issues of unobserved structural modes, dominant structural modes, and the trade-offs involved in sensor placement for space station. This procedure for sensor placement will be applied to revised, and potentially more detailed, finite element models of the space station configuration and assembly sequence.

Judging Criterion of Controlled Structures with Closely Spaced Natural Frequencies

International Nuclear Information System (INIS)

Xie Faxiang; Sun Limin

2010-01-01

The structures with closely spaced natural frequencies widely exist in civil engineering; however, the judging criterion of the density of closely spaced frequencies is in dispute. This paper suggests a judging criterion for structures with closely spaced natural frequencies based on the analysis on a controlled 2-DOF structure. The analysis results indicate that the optimal control gain of the structure with velocity feedback is dependent on the frequency density parameter of structure and the maximum attainable additional modal damping ratio is 1.72 times of the frequency density parameter when state feedback is applied. Based on a brief review on the previous researches, a judging criterion related the minimum frequency density parameter and the required mode damping ratio was proposed.

Minimizing guard ring dead space in silicon detectors with an n-type guard ring at the edge of the detector

International Nuclear Information System (INIS)

Palviainen, Tanja; Tuuva, Tuure; Leinonen, Kari

2007-01-01

Detectors with n-type silicon with an n + -type guard ring were investigated. In the present work, a new p + /n/n + detector structure with an n + guard ring is described. The guard ring is placed at the edge of the detector. The detector depletion region extends also sideways, allowing for signal collection very close to the n-guard ring. In this kind of detector structure, the dead space of the detector is minimized to be only below the guard ring. This is proved by simulations done using Silvaco/ATLAS software

Minimizing guard ring dead space in silicon detectors with an n-type guard ring at the edge of the detector

Energy Technology Data Exchange (ETDEWEB)

Palviainen, Tanja [Lappeenranta University of Technology, P.O. Box 20, FIN-53851 Lappeenranta (Finland)]. E-mail: tanja.palviainen@lut.fi; Tuuva, Tuure [Lappeenranta University of Technology, P.O. Box 20, FIN-53851 Lappeenranta (Finland); Leinonen, Kari [Lappeenranta University of Technology, P.O. Box 20, FIN-53851 Lappeenranta (Finland)

2007-04-01

Detectors with n-type silicon with an n{sup +}-type guard ring were investigated. In the present work, a new p{sup +}/n/n{sup +} detector structure with an n{sup +} guard ring is described. The guard ring is placed at the edge of the detector. The detector depletion region extends also sideways, allowing for signal collection very close to the n-guard ring. In this kind of detector structure, the dead space of the detector is minimized to be only below the guard ring. This is proved by simulations done using Silvaco/ATLAS software.

Materials space of solid-state electrolytes: unraveling chemical composition-structure-ionic conductivity relationships in garnet-type metal oxides using cheminformatics virtual screening approaches.

Science.gov (United States)

Kireeva, Natalia; Pervov, Vladislav S

2017-08-09

The organic electrolytes of most current commercial rechargeable Li-ion batteries (LiBs) are flammable, toxic, and have limited electrochemical energy windows. All-solid-state battery technology promises improved safety, cycling performance, electrochemical stability, and possibility of device miniaturization and enables a number of breakthrough technologies towards the development of new high power and energy density microbatteries for electronics with low processing cost, solid oxide fuel cells, electrochromic devices, etc. Currently, rational materials design is attracting significant attention, which has resulted in a strong demand for methodologies that can accelerate the design of materials with tailored properties; cheminformatics can be considered as an efficient tool in this respect. This study was focused on several aspects: (i) identification of the parameters responsible for high Li-ion conductivity in garnet structured oxides; (ii) development of quantitative models to elucidate composition-structure-Li ionic conductivity relationships, taking into account the experimental details of sample preparation; (iii) circumscription of the materials space of solid garnet-type electrolytes, which is attractive for virtual screening. Several candidate compounds have been recommended for synthesis as potential solid state electrolyte materials.

Development of magnetostrictive active members for control of space structures

Science.gov (United States)

Johnson, Bruce G.; Avakian, Kevin M.; Fenn, Ralph C.; Gaffney, Monique S.; Gerver, Michael J.; Hawkey, Timothy J.; Boudreau, Donald J.

1992-08-01

The goal of this Phase 2 Small Business Innovative Research (SBIR) project was to determine the technical feasibility of developing magnetostrictive active members for use as truss elements in space structures. Active members control elastic vibrations of truss-based space structures and integrate the functions of truss structure element, actively controlled actuator, and sensor. The active members must control structural motion to the sub-micron level and, for many proposed space applications, work at cryogenic temperatures. Under this program both room temperature and cryogenic temperature magnetostrictive active members were designed, fabricated, and tested. The results of these performance tests indicated that room temperature magnetostrictive actuators feature higher strain, stiffness, and force capability with lower amplifier requirements than similarly sized piezoelectric or electrostrictive active members, at the cost of higher mass. Two different cryogenic temperature magnetostrictive materials were tested at liquid nitrogen temperatures, both with larger strain capability than the room temperature magnetostrictive materials. The cryogenic active member development included the design and fabrication of a cryostat that allows operation of the cryogenic active member in a space structure testbed.

Track structure model of cell damage in space flight

Science.gov (United States)

Katz, Robert; Cucinotta, Francis A.; Wilson, John W.; Shinn, Judy L.; Ngo, Duc M.

1992-01-01

The phenomenological track-structure model of cell damage is discussed. A description of the application of the track-structure model with the NASA Langley transport code for laboratory and space radiation is given. Comparisons to experimental results for cell survival during exposure to monoenergetic, heavy-ion beams are made. The model is also applied to predict cell damage rates and relative biological effectiveness for deep-space exposures.

An optimum organizational structure for a large earth-orbiting multidisciplinary space base. Ph.D. Thesis - Fla. State Univ., 1973

Science.gov (United States)

Ragusa, J. M.

1975-01-01

An optimum hypothetical organizational structure was studied for a large earth-orbiting, multidisciplinary research and applications space base manned by a crew of technologists. Because such a facility does not presently exist, in situ empirical testing was not possible. Study activity was, therefore, concerned with the identification of a desired organizational structural model rather than with the empirical testing of the model. The essential finding of this research was that a four-level project type total matrix model will optimize the efficiency and effectiveness of space base technologists.

Schools as Racial Spaces: Understanding and Resisting Structural Racism

Science.gov (United States)

Blaisdell, Benjamin

2016-01-01

Analyzing schools as racial spaces can help researchers examine the role of teachers in the perpetuation of structural racism in schools. Based on ethnographic and autoethnographic work, this article offers examples of schools as racial spaces, spaces where whiteness controlled access. It also highlights four teachers who pursued racial equity in…

Captive chimpanzee (Pan troglodytes) behavior as a function of space per animal and enclosure type.

Science.gov (United States)

Neal Webb, Sarah J; Hau, Jann; Schapiro, Steven J

2018-03-01

Space per animal, or animal density, and enclosure type are important elements of functionally appropriate captive environments (FACEs) for chimpanzees. The National Institutes of Health (NIH) recommends that captive chimpanzees be maintained in areas of >250 ft 2 /animal. Several studies have investigated chimpanzee behavior in relation to space per animal, but only two studies have examined these variables while attempting to hold environmental complexity constant. Both have found few, if any, significant differences in behavior associated with increased space per animal. The NIH does not provide recommendations pertaining to enclosure type. Although Primadomes™ and corrals are considered acceptable FACE housing, no studies have investigated chimpanzee behavior in relation to these two common types of enclosures. We examined the NIH space per animal recommendation, and the effects of enclosure type, while maintaining similar levels of environmental complexity. We used focal animal observations to record the behavior of 22 chimpanzees in three social groups following within-facility housing transfers. Chimpanzees that were moved from an area with space below the NIH recommendation to the same type of enclosure with space above the recommendation (dome to double dome) exhibited significantly more locomotion and behavioral diversity post-transfer. Chimpanzees that were moved from an area with space below the recommendation to a different type of enclosure with space above the recommendation (dome to corral) exhibited significant increases in foraging and behavioral diversity, and a decrease in rough scratching. Lastly, chimpanzees that were moved from an area above the recommendation to a different enclosure type with space equal to the recommendation (corral to double dome) exhibited an increase in behavioral diversity. These results add to the body of literature that addresses the concept of specific minimum space requirements per chimpanzee, and highlight the

Generators with interior degeneracy on spaces of L^2 type

Directory of Open Access Journals (Sweden)

Genni Fragnelli

2012-10-01

Full Text Available We consider operators in divergence and in nondivergence form with degeneracy at the interior of the space domain. Characterizing the domain of the operators, we prove that they generate positive analytic semigroups on spaces of L^2 type. Finally, some applications to linear and semilinear parabolic evolution problems and to linear hyperbolic ones are presented.

Design and volume optimization of space structures

KAUST Repository

Jiang, Caigui; Tang, Chengcheng; Seidel, Hans-Peter; Wonka, Peter

2017-01-01

We study the design and optimization of statically sound and materially efficient space structures constructed by connected beams. We propose a systematic computational framework for the design of space structures that incorporates static soundness, approximation of reference surfaces, boundary alignment, and geometric regularity. To tackle this challenging problem, we first jointly optimize node positions and connectivity through a nonlinear continuous optimization algorithm. Next, with fixed nodes and connectivity, we formulate the assignment of beam cross sections as a mixed-integer programming problem with a bilinear objective function and quadratic constraints. We solve this problem with a novel and practical alternating direction method based on linear programming relaxation. The capability and efficiency of the algorithms and the computational framework are validated by a variety of examples and comparisons.

Design and volume optimization of space structures

KAUST Repository

Jiang, Caigui

2017-07-21

We study the design and optimization of statically sound and materially efficient space structures constructed by connected beams. We propose a systematic computational framework for the design of space structures that incorporates static soundness, approximation of reference surfaces, boundary alignment, and geometric regularity. To tackle this challenging problem, we first jointly optimize node positions and connectivity through a nonlinear continuous optimization algorithm. Next, with fixed nodes and connectivity, we formulate the assignment of beam cross sections as a mixed-integer programming problem with a bilinear objective function and quadratic constraints. We solve this problem with a novel and practical alternating direction method based on linear programming relaxation. The capability and efficiency of the algorithms and the computational framework are validated by a variety of examples and comparisons.

Spaced Seed Data Structures for De Novo Assembly

Directory of Open Access Journals (Sweden)

Inanç Birol

2015-01-01

Full Text Available De novo assembly of the genome of a species is essential in the absence of a reference genome sequence. Many scalable assembly algorithms use the de Bruijn graph (DBG paradigm to reconstruct genomes, where a table of subsequences of a certain length is derived from the reads, and their overlaps are analyzed to assemble sequences. Despite longer subsequences unlocking longer genomic features for assembly, associated increase in compute resources limits the practicability of DBG over other assembly archetypes already designed for longer reads. Here, we revisit the DBG paradigm to adapt it to the changing sequencing technology landscape and introduce three data structure designs for spaced seeds in the form of paired subsequences. These data structures address memory and run time constraints imposed by longer reads. We observe that when a fixed distance separates seed pairs, it provides increased sequence specificity with increased gap length. Further, we note that Bloom filters would be suitable to implicitly store spaced seeds and be tolerant to sequencing errors. Building on this concept, we describe a data structure for tracking the frequencies of observed spaced seeds. These data structure designs will have applications in genome, transcriptome and metagenome assemblies, and read error correction.

K-nearest uphill clustering in the protein structure space

KAUST Repository

Cui, Xuefeng; Gao, Xin

2016-01-01

The protein structure classification problem, which is to assign a protein structure to a cluster of similar proteins, is one of the most fundamental problems in the construction and application of the protein structure space. Early manually curated

The homogeneous geometries of real hyperbolic space

DEFF Research Database (Denmark)

Castrillón López, Marco; Gadea, Pedro Martínez; Swann, Andrew Francis

We describe the holonomy algebras of all canonical connections of homogeneous structures on real hyperbolic spaces in all dimensions. The structural results obtained then lead to a determination of the types, in the sense of Tricerri and Vanhecke, of the corresponding homogeneous tensors. We use...... our analysis to show that the moduli space of homogeneous structures on real hyperbolic space has two connected components....

K-nearest uphill clustering in the protein structure space

KAUST Repository

Cui, Xuefeng

2016-08-26

The protein structure classification problem, which is to assign a protein structure to a cluster of similar proteins, is one of the most fundamental problems in the construction and application of the protein structure space. Early manually curated protein structure classifications (e.g., SCOP and CATH) are very successful, but recently suffer the slow updating problem because of the increased throughput of newly solved protein structures. Thus, fully automatic methods to cluster proteins in the protein structure space have been designed and developed. In this study, we observed that the SCOP superfamilies are highly consistent with clustering trees representing hierarchical clustering procedures, but the tree cutting is very challenging and becomes the bottleneck of clustering accuracy. To overcome this challenge, we proposed a novel density-based K-nearest uphill clustering method that effectively eliminates noisy pairwise protein structure similarities and identifies density peaks as cluster centers. Specifically, the density peaks are identified based on K-nearest uphills (i.e., proteins with higher densities) and K-nearest neighbors. To our knowledge, this is the first attempt to apply and develop density-based clustering methods in the protein structure space. Our results show that our density-based clustering method outperforms the state-of-the-art clustering methods previously applied to the problem. Moreover, we observed that computational methods and human experts could produce highly similar clusters at high precision values, while computational methods also suggest to split some large superfamilies into smaller clusters. © 2016 Elsevier B.V.

T-dualization of type II superstring theory in double space

Energy Technology Data Exchange (ETDEWEB)

Nikolic, B.; Sazdovic, B. [University of Belgrade, Institute of Physics Belgrade, Belgrade (Serbia)

2017-03-15

In this article we offer a new interpretation of the T-dualization procedure of type II superstring theory in the double space framework. We use the ghost free action of type II superstring in pure spinor formulation in approximation of constant background fields up to the quadratic terms. T-dualization along any subset of the initial coordinates, x{sup a}, is equivalent to the permutation of this subset with subset of the corresponding T-dual coordinates, y{sub a}, in double space coordinate Z{sup M} = (x{sup μ}, y{sub μ}). Requiring that the T-dual transformation law after the exchange x{sup a} <-> y{sub a} has the same form as the initial one, we obtain the T-dual NS-NS and NS-R background fields. The T-dual R-R field strength is determined up to one arbitrary constant under some assumptions. The compatibility between supersymmetry and T-duality produces a change of bar spinors and R-R field strength. If we dualize an odd number of dimensions x{sup a}, such a change flips type IIA/B to type II B/A. If we T-dualize the time-like direction, one imaginary unit i maps type II superstring theories to type II{sup *} ones. (orig.)

Structural optimization via a design space hierarchy

Science.gov (United States)

Vanderplaats, G. N.

1976-01-01

Mathematical programming techniques provide a general approach to automated structural design. An iterative method is proposed in which design is treated as a hierarchy of subproblems, one being locally constrained and the other being locally unconstrained. It is assumed that the design space is locally convex in the case of good initial designs and that the objective and constraint functions are continuous, with continuous first derivatives. A general design algorithm is outlined for finding a move direction which will decrease the value of the objective function while maintaining a feasible design. The case of one-dimensional search in a two-variable design space is discussed. Possible applications are discussed. A major feature of the proposed algorithm is its application to problems which are inherently ill-conditioned, such as design of structures for optimum geometry.

Stellar Photometric Structures of the Host Galaxies of Nearby Type 1 Active Galactic Nuclei

Science.gov (United States)

Kim, Minjin; Ho, Luis C.; Peng, Chien Y.; Barth, Aaron J.; Im, Myungshin

2017-10-01

We present detailed image analysis of rest-frame optical images of 235 low-redshift (z ≲ 0.35) Type 1 active galactic nuclei (AGNs) observed with the Hubble Space Telescope. The high-resolution images enable us to perform rigorous two-dimensional image modeling to decouple the luminous central point source from the host galaxy, which, when warranted, is further decomposed into its principal structural components (bulge, bar, and disk). In many cases, care must be taken to account for structural complexities such as spiral arms, tidal features, and overlapping or interacting companion galaxies. We employ Fourier modes to characterize the degree of asymmetry of the light distribution of the stars as a quantitative measure of morphological distortion due to interactions or mergers. We examine the dependence of the physical parameters of the host galaxies on the properties of the AGNs, namely, radio-loudness and the width of the broad emission lines. In accordance with previous studies, narrow-line (Hβ FWHM ≤ 2000 km s-1) Type 1 AGNs, in contrast to their broad-line (Hβ FWHM > 2000 km s-1) counterparts, are preferentially hosted in later-type, lower-luminosity galaxies, which have a higher incidence of pseudo-bulges, are more frequently barred, and are less morphologically disturbed. This suggests that narrow-line Type 1 AGNs experienced a more quiescent evolutionary history driven primarily by internal secular evolution instead of external dynamical perturbations. The fraction of AGN hosts showing merger signatures is larger for more luminous sources. Radio-loud AGNs generally preferentially live in earlier-type (bulge-dominated), more massive hosts, although a minority of them appear to contain a significant disk component. We do not find convincing evidence for enhanced merger signatures in the radio-loud population. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute

Toward a standardized structural-functional group connectome in MNI space.

Science.gov (United States)

Horn, Andreas; Blankenburg, Felix

2016-01-01

The analysis of the structural architecture of the human brain in terms of connectivity between its subregions has provided profound insights into its underlying functional organization and has coined the concept of the "connectome", a structural description of the elements forming the human brain and the connections among them. Here, as a proof of concept, we introduce a novel group connectome in standard space based on a large sample of 169 subjects from the Enhanced Nathan Kline Institute-Rockland Sample (eNKI-RS). Whole brain structural connectomes of each subject were estimated with a global tracking approach, and the resulting fiber tracts were warped into standard stereotactic (MNI) space using DARTEL. Employing this group connectome, the results of published tracking studies (i.e., the JHU white matter and Oxford thalamic connectivity atlas) could be largely reproduced directly within MNI space. In a second analysis, a study that examined structural connectivity between regions of a functional network, namely the default mode network, was reproduced. Voxel-wise structural centrality was then calculated and compared to others' findings. Furthermore, including additional resting-state fMRI data from the same subjects, structural and functional connectivity matrices between approximately forty thousand nodes of the brain were calculated. This was done to estimate structure-function agreement indices of voxel-wise whole brain connectivity. Taken together, the combination of a novel whole brain fiber tracking approach and an advanced normalization method led to a group connectome that allowed (at least heuristically) performing fiber tracking directly within MNI space. Such an approach may be used for various purposes like the analysis of structural connectivity and modeling experiments that aim at studying the structure-function relationship of the human connectome. Moreover, it may even represent a first step toward a standard DTI template of the human brain

Moduli space of Calabi-Yau manifolds

International Nuclear Information System (INIS)

Candelas, P.; De la Ossa, X.C.

1991-01-01

We present an accessible account of the local geometry of the parameter space of Calabi-Yau manifolds. It is shown that the parameter space decomposes, at least locally, into a product with the space of parameters of the complex structure as one factor and a complex extension of the parameter space of the Kaehler class as the other. It is also shown that each of these spaces is itself a Kaehler manifold and is moreover a Kaehler manifold of restricted type. There is a remarkable symmetry in the intrinsic structures of the two parameter spaces and the relevance of this to the conjectured existence of mirror manifolds is discussed. The two parameter spaces behave differently with respect to modular transformations and it is argued that the role of quantum corrections is to restore the symmetry between the two types of parameters so as to enforce modular invariance. (orig.)

Dynamics Analysis of Origami-Folded Deployable Space Structures with Elastic Hinges

Data.gov (United States)

National Aeronautics and Space Administration — The future of space exploration needs highly sophisticated deployable space structure technology in order to achieve the ambitious goals being set today. Several...

Astronaut Ross Approaches Assembly Concept for Construction of Erectable Space Structure (ACCESS)

Science.gov (United States)

1999-01-01

The crew assigned to the STS-61B mission included Bryan D. O'Conner, pilot; Brewster H. Shaw, commander; Charles D. Walker, payload specialist; mission specialists Jerry L. Ross, Mary L. Cleave, and Sherwood C. Spring; and Rodolpho Neri Vela, payload specialist. Launched aboard the Space Shuttle Atlantis November 28, 1985 at 7:29:00 pm (EST), the STS-61B mission's primary payload included three communications satellites: MORELOS-B (Mexico); AUSSAT-2 (Australia); and SATCOM KU-2 (RCA Americom). Two experiments were conducted to test assembling erectable structures in space: EASE (Experimental Assembly of Structures in Extravehicular Activity), and ACCESS (Assembly Concept for Construction of Erectable Space Structure). In a joint venture between NASA/Langley Research Center in Hampton, Virginia, and the Marshall Space Flight Center (MSFC), EASE and ACCESS were developed and demonstrated at MSFC's Neutral Buoyancy Simulator (NBS). In this STS-61B onboard photo, astronaut Ross, perched on the Manipulator Foot Restraint (MFR) approaches the erected ACCESS. The primary objective of these experiments was to test the structural assembly concepts for suitability as the framework for larger space structures and to identify ways to improve the productivity of space construction.

Invariant subspaces in some function spaces on symmetric spaces. II

International Nuclear Information System (INIS)

Platonov, S S

1998-01-01

Let G be a semisimple connected Lie group with finite centre, K a maximal compact subgroup of G, and M=G/K a Riemannian symmetric space of non-compact type. We study the problem of describing the structure of closed linear subspaces in various function spaces on M that are invariant under the quasiregular representation of the group G. We consider the case when M is a symplectic symmetric space of rank 1

Quantum influence of topological defects in Goedel-type space-times

Energy Technology Data Exchange (ETDEWEB)

Carvalho, Josevi [Universidade Federal de Campina Grande, Unidade Academica de Tecnologia de Alimentos, Centro de Ciencias e Tecnologia Agroalimentar, Pombal, PB (Brazil); Carvalho, M.; Alexandre, M. de [Universidade Federal de Alagoas, Instituto de Fisica, Maceio, AL (Brazil); Furtado, Claudio [Universidade Federal da Paraiba, Cidade Universitaria, Departamento de Fisica, CCEN, Joao Pessoa, PB (Brazil)

2014-06-15

In this contribution, some solutions of the Klein-Gordon equation in Goedel-type metrics with an embedded cosmic string are considered. The quantum dynamics of a scalar particle in three spaces whose metrics are described by different classes of Goedel solutions, with a cosmic string passing through the spaces, is found. The energy levels and eigenfunctions of the Klein-Gordon operator are obtained. We show that these eigenvalues and eigenfunctions depend on the parameter characterizing the presence of a cosmic string in the space-time. We note that the presence of topological defects breaks the degeneracy of energy levels. (orig.)

Interacting Conceptual Spaces

OpenAIRE

Bolt, Josef; Coecke, Bob; Genovese, Fabrizio; Lewis, Martha; Marsden, Daniel; Piedeleu, Robin

2016-01-01

We propose applying the categorical compositional scheme of [6] to conceptual space models of cognition. In order to do this we introduce the category of convex relations as a new setting for categorical compositional semantics, emphasizing the convex structure important to conceptual space applications. We show how conceptual spaces for composite types such as adjectives and verbs can be constructed. We illustrate this new model on detailed examples.

Sparse RNA folding revisited: space-efficient minimum free energy structure prediction.

Science.gov (United States)

Will, Sebastian; Jabbari, Hosna

2016-01-01

RNA secondary structure prediction by energy minimization is the central computational tool for the analysis of structural non-coding RNAs and their interactions. Sparsification has been successfully applied to improve the time efficiency of various structure prediction algorithms while guaranteeing the same result; however, for many such folding problems, space efficiency is of even greater concern, particularly for long RNA sequences. So far, space-efficient sparsified RNA folding with fold reconstruction was solved only for simple base-pair-based pseudo-energy models. Here, we revisit the problem of space-efficient free energy minimization. Whereas the space-efficient minimization of the free energy has been sketched before, the reconstruction of the optimum structure has not even been discussed. We show that this reconstruction is not possible in trivial extension of the method for simple energy models. Then, we present the time- and space-efficient sparsified free energy minimization algorithm SparseMFEFold that guarantees MFE structure prediction. In particular, this novel algorithm provides efficient fold reconstruction based on dynamically garbage-collected trace arrows. The complexity of our algorithm depends on two parameters, the number of candidates Z and the number of trace arrows T; both are bounded by [Formula: see text], but are typically much smaller. The time complexity of RNA folding is reduced from [Formula: see text] to [Formula: see text]; the space complexity, from [Formula: see text] to [Formula: see text]. Our empirical results show more than 80 % space savings over RNAfold [Vienna RNA package] on the long RNAs from the RNA STRAND database (≥2500 bases). The presented technique is intentionally generalizable to complex prediction algorithms; due to their high space demands, algorithms like pseudoknot prediction and RNA-RNA-interaction prediction are expected to profit even stronger than "standard" MFE folding. SparseMFEFold is free

Molecular Dynamic Simulation of Space and Earth-Grown Crystal Structures of Thermostable T1 Lipase Geobacillus zalihae Revealed a Better Structure.

Science.gov (United States)

Ishak, Siti Nor Hasmah; Aris, Sayangku Nor Ariati Mohamad; Halim, Khairul Bariyyah Abd; Ali, Mohd Shukuri Mohamad; Leow, Thean Chor; Kamarudin, Nor Hafizah Ahmad; Masomian, Malihe; Rahman, Raja Noor Zaliha Raja Abd

2017-09-25

Less sedimentation and convection in a microgravity environment has become a well-suited condition for growing high quality protein crystals. Thermostable T1 lipase derived from bacterium Geobacillus zalihae has been crystallized using the counter diffusion method under space and earth conditions. Preliminary study using YASARA molecular modeling structure program for both structures showed differences in number of hydrogen bond, ionic interaction, and conformation. The space-grown crystal structure contains more hydrogen bonds as compared with the earth-grown crystal structure. A molecular dynamics simulation study was used to provide insight on the fluctuations and conformational changes of both T1 lipase structures. The analysis of root mean square deviation (RMSD), radius of gyration, and root mean square fluctuation (RMSF) showed that space-grown structure is more stable than the earth-grown structure. Space-structure also showed more hydrogen bonds and ion interactions compared to the earth-grown structure. Further analysis also revealed that the space-grown structure has long-lived interactions, hence it is considered as the more stable structure. This study provides the conformational dynamics of T1 lipase crystal structure grown in space and earth condition.

Notes on qubit phase space and discrete symplectic structures

International Nuclear Information System (INIS)

Livine, Etera R

2010-01-01

We start from Wootter's construction of discrete phase spaces and Wigner functions for qubits and more generally for finite-dimensional Hilbert spaces. We look at this framework from a non-commutative space perspective and we focus on the Moyal product and the differential calculus on these discrete phase spaces. In particular, the qubit phase space provides the simplest example of a four-point non-commutative phase space. We give an explicit expression of the Moyal bracket as a differential operator. We then compare the quantum dynamics encoded by the Moyal bracket to the classical dynamics: we show that the classical Poisson bracket does not satisfy the Jacobi identity thus leaving the Moyal bracket as the only consistent symplectic structure. We finally generalize our analysis to Hilbert spaces of prime dimensions d and their associated d x d phase spaces.

Assembly of Space CFRP Structures with Racing Sailing Boats Technology

Science.gov (United States)

Nieto, Jose; Yuste, Laura; Pipo, Alvaro; Santarsiero, Pablo; Bureo, Rafael

2014-06-01

Carbon Fiber Reinforced Plastic (CFRP) is commonly used in space applications to get structures with good mechanical performances and a reduced mass. Most of larger parts of spatial structures are already made of CFRP but the achieved weight saving may be jeopardized by the use of metallic brackets as joining elements. This paper describes the work carried out to study and evaluate ways of reducing weight and costs of the joints between structural elements commonly used in space applications.The main objective of this project is to adapt design solutions coming from the racing sailing boats technology to space applications: the use of out-of autoclave (OoA) cured CFRP joints. In addition to that other CFRP solution common in space business, 3D- RTM Bracket, has been evaluated.This development studies the manufacturing and assembly feasibility making use of these CFRP technologies.This study also compares traditional metallic solutions with innovative CFRP ones in terms of mechanical performances at elementary level. Weight and cost of presented solutions are also compared.

Central Structural Parameters of Early-Type Galaxies as Viewed with Nicmos on the Hubble Space Telescope

Science.gov (United States)

Ravindranath, Swara; Ho, Luis C.; Peng, Chien Y.; Filippenko, Alexei V.; Sargent, Wallace L. W.

2001-08-01

We present surface photometry for the central regions of a sample of 33 early-type (E, S0, and S0/a) galaxies observed at 1.6 μm (H band) using the Hubble Space Telescope. Dust absorption has less of an impact on the galaxy morphologies in the near-infrared than found in previous work based on observations at optical wavelengths. When present, dust seems to be most commonly associated with optical line emission. We employ a new technique of two-dimensional fitting to extract quantitative parameters for the bulge light distribution and nuclear point sources, taking into consideration the effects of the point-spread function. By parameterizing the bulge profile with a Nuker law, we confirm that the central surface brightness distributions largely fall into two categories, each of which correlates with the global properties of the galaxies. ``Core'' galaxies tend to be luminous elliptical galaxies with boxy or pure elliptical isophotes, whereas ``power-law'' galaxies are preferentially lower luminosity systems with disky isophotes. The infrared surface brightness profiles are very similar to those in the optical, with notable exceptions being very dusty objects. Similar to the study of Faber et al., based on optical data, we find that galaxy cores obey a set of fundamental plane relations wherein more luminous galaxies with higher central stellar velocity dispersions generally possess larger cores with lower surface brightnesses. Unlike most previous studies, however, we do not find a clear gap in the distribution of inner cusp slopes; several objects have inner cusp slopes (0.3law galaxies. The nature of these intermediate objects is unclear. We draw attention to two objects in the sample that appear to be promising cases of galaxies with isothermal cores that are not the brightest members of a cluster. Unresolved nuclear point sources are found in ~50% of the sample galaxies, roughly independent of profile type, with magnitudes in the range mnucH=12.8 to 17.4 mag

The role of defensible space for residential structure protection during wildfires

Science.gov (United States)

Syphard, Alexandra D.; Brennan, Teresa J.; Keeley, Jon E.

2014-01-01

With the potential for worsening fire conditions, discussion is escalating over how to best reduce effects on urban communities. A widely supported strategy is the creation of defensible space immediately surrounding homes and other structures. Although state and local governments publish specific guidelines and requirements, there is little empirical evidence to suggest how much vegetation modification is needed to provide significant benefits. We analysed the role of defensible space by mapping and measuring a suite of variables on modern pre-fire aerial photography for 1000 destroyed and 1000 surviving structures for all fires where homes burned from 2001 to 2010 in San Diego County, CA, USA. Structures were more likely to survive a fire with defensible space immediately adjacent to them. The most effective treatment distance varied between 5 and 20 m (16–58 ft) from the structure, but distances larger than 30 m (100 ft) did not provide additional protection, even for structures located on steep slopes. The most effective actions were reducing woody cover up to 40% immediately adjacent to structures and ensuring that vegetation does not overhang or touch the structure. Multiple-regression models showed landscape-scale factors, including low housing density and distances to major roads, were more important in explaining structure destruction. The best long-term solution will involve a suite of prevention measures that include defensible space as well as building design approach, community education and proactive land use planning that limits exposure to fire.

Low Carbon Design Research on the Space Layout Types of Office Buildings

Science.gov (United States)

Xia, Bing

2018-01-01

It is beneficial to find out the relationship of the spatial layout and low-carbon design in order to reduce buildings’ carbon emissions in the conceptual design phase. This paper analyzes and compares shape coefficient values, annual energy consumption and lighting performance of office buildings of different space layout types in Shanghai. Based on morphological characteristics of different types, the study also analyzes and presents low-carbon design strategies for each single type. This study assumes that architects should conduct passive and active design according to the specific building space layout, so that to make best use of the advantages and bypassing the disadvantages, in order to maximally reduce buildings’ carbon emissions.

On the existence of conformal Killing vectors for ST-homogeneous Godel type space-times

Energy Technology Data Exchange (ETDEWEB)

Parra, Y.; Patino, A.; Percoco, U. [Laboratorio de Fisica Teorica, Facultad de Ciencias Universidad de los Andes, Merida 5101 (Venezuela); Tsamparlis, M. [seccion de Astronomia-Astrofisica-Mecanica, Universidad de Atenas, Atenas 157 83 (Greece)

2006-07-01

Tsamparlis with another authors have developed a systematic method for computing of the conformal algebra of 1+3 space-times. The proper CKV's are found in terms of gradient CKVs of the 3-space. In this paper we apply Tsamparlis' results to the study CKVs of the Godel ST-Homogeneous type spacetimes. We find that the only space-time admitting proper CKV's is the ST-Homogeneous Godel type with m{sup 2} = 4{omega}{sup 2} (RT). (Author)

Comparison of Requirements for Composite Structures for Aircraft and Space Applications

Science.gov (United States)

Raju, Ivatury S.; Elliot, Kenny B.; Hampton, Roy W.; Knight, Norman F., Jr.; Aggarwal, Pravin; Engelstad, Stephen P.; Chang, James B.

2010-01-01

In this report, the aircraft and space vehicle requirements for composite structures are compared. It is a valuable exercise to study composite structural design approaches used in the airframe industry and to adopt methodology that is applicable for space vehicles. The missions, environments, analysis methods, analysis validation approaches, testing programs, build quantities, inspection, and maintenance procedures used by the airframe industry, in general, are not transferable to spaceflight hardware. Therefore, while the application of composite design approaches from aircraft and other industries is appealing, many aspects cannot be directly utilized. Nevertheless, experiences and research for composite aircraft structures may be of use in unexpected arenas as space exploration technology develops, and so continued technology exchanges are encouraged.

Isometries on Banach spaces function spaces

CERN Document Server

Fleming, Richard J

2002-01-01

Fundamental to the study of any mathematical structure is an understanding of its symmetries. In the class of Banach spaces, this leads naturally to a study of isometries-the linear transformations that preserve distances. In his foundational treatise, Banach showed that every linear isometry on the space of continuous functions on a compact metric space must transform a continuous function x into a continuous function y satisfying y(t) = h(t)x(p(t)), where p is a homeomorphism and |h| is identically one.Isometries on Banach Spaces: Function Spaces is the first of two planned volumes that survey investigations of Banach-space isometries. This volume emphasizes the characterization of isometries and focuses on establishing the type of explicit, canonical form given above in a variety of settings. After an introductory discussion of isometries in general, four chapters are devoted to describing the isometries on classical function spaces. The final chapter explores isometries on Banach algebras.This treatment p...

New tetragonal derivatives of cubic NaZn13-type structure: RNi6Si6 compounds, crystal structure and magnetic ordering (R=Y, La, Ce, Sm, Gd–Yb)

International Nuclear Information System (INIS)

Pani, M.; Manfrinetti, P.; Provino, A.; Yuan, Fang; Mozharivskyj, Y.; Morozkin, A.V.; Knotko, A.V.; Garshev, A.V.; Yapaskurt, V.O.; Isnard, O.

2014-01-01

Novel RNi 6 Si 6 compounds adopt the new CeNi 6 Si 6 -type structure for R=La–Ce (tP52, space group P4/nbm N 125-1) and new YNi 6 Si 6 -type structure for R=Y, Sm, Gd–Yb (tP52, space group P4 ¯ b2N 117) that are tetragonal derivative of NaZn 13 -type structure, like LaCo 9 Si 4 -type. The CeNi 6 Si 6 , GdNi 6 Si 6 , TbNi 6 Si 6 , DyNi 6 Si 6 and HoNi 6 Si 6 compounds are Curie–Weiss paramagnets down to ∼30 K, and do not order magnetically down to 5 K. However, the inverse paramagnetic susceptibility of LaNi 6 Si 6 does not follow Curie–Weiss law. The DyNi 6 Si 6 shows ferromagnetic-like saturation behaviour at 5 K in applied fields of 50 kOe, giving rise to a magnetic moment value of 6.5 μ B /f.u. in 50 kOe. The powder neutron diffraction study in zero applied filed indicates square modulated the c-collinear antiferromagnetic ordering of TbNi 6 Si 6 with K=[±1/4, ±1/4, 0] wave vector below ∼10 K. - Graphical abstract: Novel (La, Ce)Ni 6 Si 6 compounds adopt the new CeNi 6 Si 6 -type structure and (Y, Sm, Gd–Yb) adopt the new YNi 6 Si 6 -type structure that are tetragonal derivative of NaZn 13 -type structure, like LaCo 9 Si 4 -type. The CeNi 6 Si 6 , GdNi 6 Si 6 , TbNi 6 Si 6 , DyNi 6 Si 6 and HoNi 6 Si 6 compounds are Curie–Weiss paramagnets down to ∼30 K, and do not order magnetically down to 4.2 K. The powder neutron diffraction study in zero applied filed indicates square modulated the c-collinear antiferromagnetic ordering of TbNi 6 Si 6 with K=[±1/4, ±1/4, 0] wave vector below ∼10 K. Display Omitted - Highlights: • The new (La, Ce)Ni 6 Si 6 compounds adopt the new CeNi 6 Si 6 -type structure. • The new (Y, Sm, Gd–Yb)Ni 6 Si 6 compounds adopt the new YNi 6 Si 6 -type structure. • TbNi 6 Si 6 has square modulated c-collinear antiferromagnetic ordering below ∼10 K

Fixed points for weak contractions in metric type spaces

OpenAIRE

Gaba, Yaé Ulrich

2014-01-01

In this article, we prove some fixed point theorems in metric type spaces. This article is just a generalization some results previously proved in \\cite{niyi-gaba}. In particular, we give some coupled common fixed points theorems under weak contractions. These results extend well known similar results existing in the literature.

Engineering report. Part 2: NASA wheel and brake material tradeoff study for space shuttle type environmental requirements

Science.gov (United States)

Bok, L. D.

1973-01-01

The study included material selection and trade-off for the structural components of the wheel and brake optimizing weight vs cost and feasibility for the space shuttle type application. Analytical methods were used to determine section thickness for various materials, and a table was constructed showing weight vs. cost trade-off. The wheel and brake were further optimized by considering design philosophies that deviate from standard aircraft specifications, and designs that best utilize the materials being considered.

The Design Space of Type Checkers for XML Transformation Languages

DEFF Research Database (Denmark)

Møller, Anders; Schwartzbach, Michael Ignatieff

2005-01-01

We survey work on statically type checking XML transformations, covering a wide range of notations and ambitions. The concept of type may vary from idealizations of DTD to full-blown XML Schema or even more expressive formalisms. The notion of transformation may vary from clean and simple...... transductions to domain-specific languages or integration of XML in general-purpose programming languages. Type annotations can be either explicit or implicit, and type checking ranges from exact decidability to pragmatic approximations. We characterize and evaluate existing tools in this design space......, including a recent result of the authors providing practical type checking of full unannotated XSLT 1.0 stylesheets given general DTDs that describe the input and output languages....

Generalized fixed point theorems for compatible mappings with some types in fuzzy metric spaces

International Nuclear Information System (INIS)

Cho, Yeol Je; Sedghi, Shaban; Shobe, Nabi

2009-01-01

In this paper, we give some new definitions of compatible mappings of types (I) and (II) in fuzzy metric spaces and prove some common fixed point theorems for four mappings under the condition of compatible mappings of types (I) and (II) in complete fuzzy metric spaces. Our results extend, generalize and improve the corresponding results given by many authors.

Modelling of Structural Loads in Drag Augmented Space Debris Removal Concepts

DEFF Research Database (Denmark)

Kristensen, Anders Schmidt; Nikolajsen, Jan Ánike; Lauridsen, Peter Riddersholm

2017-01-01

A Self-deployable Deorbiting Space Structure (SDSS) is used for drag augmented space debris removal. A highly flexible frame allows for a folding of the structure by bifurcation. This research models the structural loads during the deployment and unfolding of the drag sail in Low Earth Orbit (LEO......). The Spacecraft travels with 7.8 km/s at deployment. As the drag sail unfolds instantaneously the structure must withstand the loads from the unfolding and the drag. Thermal loads are included in the FEA as the temperature varies from -80°C to +80°C during deorbit. The results are used to verify the structural...

Density perturbations due to the inhomogeneous discrete spatial structure of space-time

International Nuclear Information System (INIS)

Wolf, C.

1998-01-01

For the case that space-time permits an inhomogeneous discrete spatial structure due to varying gravitational fields or a foam-like structure of space-time, it is demonstrated that thermodynamic reasoning implies that matter-density perturbations will arise in the early universe

Magnetic order and crystal structure study of YNi{sub 4}Si-type NdNi{sub 4}Si

Energy Technology Data Exchange (ETDEWEB)

Yao, Jinlei [Research Center for Solid State Physics and Materials, School of Mathematics and Physics, Suzhou University of Science and Technology, Suzhou 215009 (China); Isnard, O. [Université Grenoble Alpes, Inst NEEL, BP166, Grenoble F-38042 (France); CNRS, Institut NEEL, 25 rue des martyrs, Grenoble F-38042 (France); Morozkin, A.V., E-mail: morozkin@tech.chem.msu.ru [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Ivanova, T.I. [Physics Department, Moscow State University, Moscow 119992 (Russian Federation); Koshkid' ko, Yu.S. [International Laboratory of High Magnetic Fields and Low Temperatures, Wrocław (Poland); VSB-Technical University of Ostrava, Ostrava-Poruba 70833 (Czech Republic); Bogdanov, A.E.; Nikitin, S.A. [Physics Department, Moscow State University, Moscow 119992 (Russian Federation); Suski, W. [International Laboratory of High Magnetic Fields and Low Temperatures, Wrocław (Poland); Polish Academy of Sciences, Trzebiatowski Institute of Low Temperatures and Structure Research, P.O. Box 1410, 50-950 Wrocław 2 (Poland)

2015-02-15

Magnetic measurements and neutron powder diffraction investigation of the magnetic structure of the orthorhombic YNi{sub 4}Si-type (space group Cmmm) NdNi{sub 4}Si compound are presented. The magnetocaloric effect of NdNi{sub 4}Si is calculated in terms of the isothermal magnetic entropy change and it reaches the maximum value of –3.3 J/kg K for a field change of 50 kOe near T{sub C}=12 K. Below ∼12 K, NdNi{sub 4}Si exhibits a commensurate b-axis collinear ferromagnetic ordering with the Cmm′m magnetic space group in a zero magnetic field. At 1.5 K, the neodymium atoms have the magnetic moment of 2.37(5) μ{sub B}. The orthorhombic crystal structure and its thermal evolution are discussed in comparison with the CaCu{sub 5}-type compound. - Graphical abstract: The NdNi{sub 4}Si supplement the series of the orthorhombic derivative of the CaCu{sub 5}-type, namely the YNi{sub 4}Si-type, RNi{sub 4}Si compounds (R=Y, La, Ce, Sm, Gd–Ho). Below ∼12 K in a zero applied magnetic field, NdNi{sub 4}Si exhibits a commensurate b-axis collinear ferromagnetic ordering with the Cmm′m magnetic space group. Compared to the CaCu{sub 5}-type NdNi{sub 4}Si compound, the YNi{sub 4}Si-type counterpart has the relatively high ferromagnetic ordering temperature (9.2 K vs. 12 K), the small magnetocaloric effect (–7.3 J/kg K vs. –3.3 J/kg K for ∆H=50 kOe), and the large magnetic anisotropy at low temperatures. In contrast with CaCu{sub 5}-type NdNi{sub 4}Si, YNi{sub 4}Si-type NdNi{sub 4}Si shows distinct hysteresis loop at 2 K.We suggest that orthorhombic distortion may be used as a prospective route for optimization of permanent magnetic properties in the family of CaCu{sub 5}-type rare earth materials. - Highlights: • Below ∼12 K the YNi{sub 4}Si-type NdNi{sub 4}Si shows a ferromagnetic ordering. • MCE of NdNi{sub 4}Si reaches value of –3.3 J/kg K in 0–50 kOe near Curie point. • NdNi{sub 4}Si exhibits b-axis ferromagnetic order with the Cmm′m magnetic space

Roentgenological structural types of the unaltered breast

International Nuclear Information System (INIS)

Kolganova, I.P.; Zal'tsman, I.N.

1981-01-01

The authors present a roentgenoanatomical analysis of normal breast specimens and mammograms of 324 healthy women aged 31 to 60. Four roentgenological structural types of the unaltered breast have been singled out: linear-reticular, lamellar-cellular, large focal, and a single polygonal shadow. These structural types were detected in age groups from 31 to 40, from 41 to 50, and from 51 to 60 with various frequency. Each type corresponds to a certain morphological and functional state of the breast. The frequency of the 2nd and 4th types decreases and of the 1st type increases with advancing age [ru

Roentgenological structural types of the unaltered breast

Energy Technology Data Exchange (ETDEWEB)

Kolganova, I P; Zal' tsman, I N [Akademiya Meditsinskikh Nauk RSFSR, Moscow. Pervyj Moskovskij Meditsinskij Inst.

1981-11-01

The authors present a roentgenoanatomical analysis of normal breast specimens and mammograms of 324 healthy women aged 31 to 60. Four roentgenological structural types of the unaltered breast have been singled out: linear-reticular, lamellar-cellular, large focal, and a single polygonal shadow. These structural types were detected in age groups from 31 to 40, from 41 to 50, and from 51 to 60 with various frequency. Each type corresponds to a certain morphological and functional state of the breast. The frequency of the 2nd and 4th types decreases and of the 1st type increases with advancing age.

Contractive type non-self mappings on metric spaces of hyperbolic type

Science.gov (United States)

Ciric, Ljubomir B.

2006-05-01

Let (X,d) be a metric space of hyperbolic type and K a nonempty closed subset of X. In this paper we study a class of mappings from K into X (not necessarily self-mappings on K), which are defined by the contractive condition (2.1) below, and a class of pairs of mappings from K into X which satisfy the condition (2.28) below. We present fixed point and common fixed point theorems which are generalizations of the corresponding fixed point theorems of Ciric [L.B. Ciric, Quasi-contraction non-self mappings on Banach spaces, Bull. Acad. Serbe Sci. Arts 23 (1998) 25-31; L.B. Ciric, J.S. Ume, M.S. Khan, H.K.T. Pathak, On some non-self mappings, Math. Nachr. 251 (2003) 28-33], Rhoades [B.E. Rhoades, A fixed point theorem for some non-self mappings, Math. Japon. 23 (1978) 457-459] and many other authors. Some examples are presented to show that our results are genuine generalizations of known results from this area.

Structures that Include a Semi-Outdoor Space

DEFF Research Database (Denmark)

Papachristou, C.; Foteinaki, Kyriaki; Kazanci, Ongun Berk

2016-01-01

The thermal environment of buildings with a second "skin" and semi-outdoor space is examined in the present study. A literature review was conducted on similar structures and only a few studies were found focusing on the thermal environment. Two different building case studies were chosen with di...

Study of static properties of magnetron-type space charges; Etude des proprietes statiques des charges d'espace du type magnetron

Energy Technology Data Exchange (ETDEWEB)

Delcroix, Jean-Loup

1953-05-30

This research thesis reports an in-depth analysis of physical properties of static regimes to address the issue of space charges. This theoretical study of the Hull magnetron is followed by the description of experiments on the Hull magnetron which highlight transitions between the different regimes. Then, another theoretical approach aims at generalising the magnetron theory, based on other types of magnetron theory (general equations of magnetron-type space charges, inverted Hull magnetron theory, circular field magnetron theory)

Alternative structures and bi-Hamiltonian systems on a Hilbert space

International Nuclear Information System (INIS)

Marmo, G; Scolarici, G; Simoni, A; Ventriglia, F

2005-01-01

We discuss transformations generated by dynamical quantum systems which are bi-unitary, i.e. unitary with respect to a pair of Hermitian structures on an infinite-dimensional complex Hilbert space. We introduce the notion of Hermitian structures in generic relative position. We provide a few necessary and sufficient conditions for two Hermitian structures to be in generic relative position to better illustrate the relevance of this notion. The group of bi-unitary transformations is considered in both the generic and the non-generic case. Finally, we generalize the analysis to real Hilbert spaces and extend to infinite dimensions results already available in the framework of finite-dimensional linear bi-Hamiltonian systems

Structure of Hilbert space operators

CERN Document Server

Jiang, Chunlan

2006-01-01

This book exposes the internal structure of non-self-adjoint operators acting on complex separable infinite dimensional Hilbert space, by analyzing and studying the commutant of operators. A unique presentation of the theorem of Cowen-Douglas operators is given. The authors take the strongly irreducible operator as a basic model, and find complete similarity invariants of Cowen-Douglas operators by using K -theory, complex geometry and operator algebra tools. Sample Chapter(s). Chapter 1: Background (153 KB). Contents: Jordan Standard Theorem and K 0 -Group; Approximate Jordan Theorem of Opera

Lagrangian space consistency relation for large scale structure

International Nuclear Information System (INIS)

Horn, Bart; Hui, Lam; Xiao, Xiao

2015-01-01

Consistency relations, which relate the squeezed limit of an (N+1)-point correlation function to an N-point function, are non-perturbative symmetry statements that hold even if the associated high momentum modes are deep in the nonlinear regime and astrophysically complex. Recently, Kehagias and Riotto and Peloso and Pietroni discovered a consistency relation applicable to large scale structure. We show that this can be recast into a simple physical statement in Lagrangian space: that the squeezed correlation function (suitably normalized) vanishes. This holds regardless of whether the correlation observables are at the same time or not, and regardless of whether multiple-streaming is present. The simplicity of this statement suggests that an analytic understanding of large scale structure in the nonlinear regime may be particularly promising in Lagrangian space

Wave fields in Weyl spaces and conditions for the existence of a preferred pseudo-Riemannian structure

International Nuclear Information System (INIS)

Audretsch, J.; Gaehler, F.; Straumann, N.

1984-01-01

Previous axiomatic approaches to general relativity which led to a Weylian structure of space-time are supplemented by a physical condition which implies the existence of a preferred pseudo-Riemannian structure. It is stipulated that the trajectories of the short wave limit of classical massive fields agree with the geodesics of the Weyl connection and it is shown that this is equivalent to the vanishing of the covariant derivative of a ''mass function'' of nontrivial Weyl type.This in turn is proven to be equivalent to the existence of a preferred metric of the conformal structure such that the Weyl connection is reducible to a connection of the bundle of orthonormal frames belonging to this distinguished metric. (orig.)

Finding Chemical Structures Corresponding to a Set of Coordinates in Chemical Descriptor Space.

Science.gov (United States)

Miyao, Tomoyuki; Funatsu, Kimito

2017-08-01

When chemical structures are searched based on descriptor values, or descriptors are interpreted based on values, it is important that corresponding chemical structures actually exist. In order to consider the existence of chemical structures located in a specific region in the chemical space, we propose to search them inside training data domains (TDDs), which are dense areas of a training dataset in the chemical space. We investigated TDDs' features using diverse and local datasets, assuming that GDB11 is the chemical universe. These two analyses showed that considering TDDs gives higher chance of finding chemical structures than a random search-based method, and that novel chemical structures actually exist inside TDDs. In addition to those findings, we tested the hypothesis that chemical structures were distributed on the limited areas of chemical space. This hypothesis was confirmed by the fact that distances among chemical structures in several descriptor spaces were much shorter than those among randomly generated coordinates in the training data range. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Structural Continuum Modeling of Space Shuttle External Tank Foam Insulation

Science.gov (United States)

Steeve, Brian; Ayala, Sam; Purlee, T. Eric; Shaw, Phillip

2006-01-01

This document is a viewgraph presentation reporting on work in modeling the foam insulation of the Space Shuttle External Tank. An analytical understanding of foam mechanics is required to design against structural failure. The Space Shuttle External Tank is covered primarily with closed cell foam to: Prevent ice, Protect structure from ascent aerodynamic and engine plume heating, and Delay break-up during re-entry. It is important that the foam does not shed unacceptable debris during ascent environment. Therefore a modeling of the foam insulation was undertaken.

Weakly nonlocal symplectic structures, Whitham method and weakly nonlocal symplectic structures of hydrodynamic type

International Nuclear Information System (INIS)

Maltsev, A Ya

2005-01-01

We consider the special type of field-theoretical symplectic structures called weakly nonlocal. The structures of this type are, in particular, very common for integrable systems such as KdV or NLS. We introduce here the special class of weakly nonlocal symplectic structures which we call weakly nonlocal symplectic structures of hydrodynamic type. We investigate then the connection of such structures with the Whitham averaging method and propose the procedure of 'averaging' the weakly nonlocal symplectic structures. The averaging procedure gives the weakly nonlocal symplectic structure of hydrodynamic type for the corresponding Whitham system. The procedure also gives 'action variables' corresponding to the wave numbers of m-phase solutions of the initial system which give the additional conservation laws for the Whitham system

Nanotube structures, methods of making nanotube structures, and methods of accessing intracellular space

Science.gov (United States)

VanDersarl, Jules J.; Xu, Alexander M.; Melosh, Nicholas A.; Tayebi, Noureddine

2016-02-23

In accordance with the purpose(s) of the present disclosure, as embodied and broadly described herein, embodiments of the present disclosure, in one aspect, relate to methods of making a structure including nanotubes, a structure including nanotubes, methods of delivering a fluid to a cell, methods of removing a fluid to a cell, methods of accessing intracellular space, and the like.

Space Density of Optically Selected Type 2 Quasars

Science.gov (United States)

Reyes, Reinabelle; Zakamska, Nadia L.; Strauss, Michael A.; Green, Joshua; Krolik, Julian H.; Shen, Yue; Richards, Gordon T.; Anderson, Scott F.; Schneider, Donald P.

2008-12-01

Type 2 quasars are luminous active galactic nuclei whose central regions are obscured by large amounts of gas and dust. In this paper, we present a catalog of type 2 quasars from the Sloan Digital Sky Survey, selected based on their optical emission lines. The catalog contains 887 objects with redshifts z < 0.83; this is 6 times larger than the previous version and is by far the largest sample of type 2 quasars in the literature. We derive the [O III]5007 luminosity function (LF) for 108.3 L sun < L [O III] < 1010 L sun (corresponding to intrinsic luminosities up to M[2500 Å] ~= -28 mag or bolometric luminosities up to 4 × 1047 erg s-1). This LF provides robust lower limits to the actual space density of obscured quasars due to our selection criteria, the details of the spectroscopic target selection, and other effects. We derive the equivalent LF for the complete sample of type 1 (unobscured) quasars and determine the ratio of type 2 to type 1 quasar number densities. Our data constrain this ratio to be at least ~1.5:1 for 108.3 L sun < L [O III] < 109.5 L sun at z < 0.3, and at least ~1.2:1 for L [O III] ~ 1010 L sun at 0.3 < z < 0.83. Type 2 quasars are at least as abundant as type 1 quasars in the relatively nearby universe (z <~ 0.8) for the highest luminosities.

Modeling and control of flexible space structures

Science.gov (United States)

Wie, B.; Bryson, A. E., Jr.

1981-01-01

The effects of actuator and sensor locations on transfer function zeros are investigated, using uniform bars and beams as generic models of flexible space structures. It is shown how finite element codes may be used directly to calculate transfer function zeros. The impulse response predicted by finite-dimensional models is compared with the exact impulse response predicted by the infinite dimensional models. It is shown that some flexible structures behave as if there were a direct transmission between actuator and sensor (equal numbers of zeros and poles in the transfer function). Finally, natural damping models for a vibrating beam are investigated since natural damping has a strong influence on the appropriate active control logic for a flexible structure.

Associated quantum vector bundles and symplectic structure on a quantum space

International Nuclear Information System (INIS)

Coquereaux, R.; Garcia, A.O.; Trinchero, R.

2000-01-01

We define a quantum generalization of the algebra of functions over an associated vector bundle of a principal bundle. Here the role of a quantum principal bundle is played by a Hopf-Galois extension. Smash products of an algebra times a Hopf algebra H are particular instances of these extensions, and in these cases we are able to define a differential calculus over their associated vector bundles without requiring the use of a (bicovariant) differential structure over H. Moreover, if H is coquasitriangular, it coacts naturally on the associated bundle, and the differential structure is covariant. We apply this construction to the case of the finite quotient of the SL q (2) function Hopf algebra at a root of unity (q 3 = 1) as the structure group, and a reduced 2-dimensional quantum plane as both the 'base manifold' and fibre, getting an algebra which generalizes the notion of classical phase space for this quantum space. We also build explicitly a differential complex for this phase space algebra, and find that levels 0 and 2 support a (co)representation of the quantum symplectic group. On this phase space we define vector fields, and with the help of the Sp q structure we introduce a symplectic form relating 1-forms to vector fields. This leads naturally to the introduction of Poisson brackets, a necessary step to do 'classical' mechanics on a quantum space, the quantum plane. (author)

Binding energy, phonon spectra and thermodynamic properties of elements with type structures A1 (Al, Cu), A2 (V, Ti2), A3 (Mg, Tiβ), A4 (Si, Sn)

International Nuclear Information System (INIS)

Sirota, N.N.; Soshnina, T.M.; Sirota, I.M.; Sokolovskij, T.D.

2001-01-01

One calculated dependences of binding energy on spacing between the nearest atoms of Al and Cu elements with A 1 type structure, of V and Ti α elements with A 2 type structure, of Mg and Ti β elements with A 3 type structure, Si and Sn elements with A 4 type structure. To calculate one applied the methods based on the Thomas-Fermi statistic theory of atom. The derived dependences were approximated using the expression in the form of the Mie-Grueneisen potential. On the basis of the Born-von-Karman model of solid body one calculated the phonon spectra using which one determined temperature dependences of specific heat, free and internal energy of the investigated elements. The calculated values of energy of atomization, equilibrium closest interatomic spacing and temperature dependences of specific heat are in compliance with the experimental data [ru

Conflict between object structural and functional affordances in peripersonal space.

Science.gov (United States)

Kalénine, Solène; Wamain, Yannick; Decroix, Jérémy; Coello, Yann

2016-10-01

Recent studies indicate that competition between conflicting action representations slows down planning of object-directed actions. The present study aims to assess whether similar conflict effects exist during manipulable object perception. Twenty-six young adults performed reach-to-grasp and semantic judgements on conflictual objects (with competing structural and functional gestures) and non-conflictual objects (with similar structural and functional gestures) presented at difference distances in a 3D virtual environment. Results highlight a space-dependent conflict between structural and functional affordances. Perceptual judgments on conflictual objects were slower that perceptual judgments on non-conflictual objects, but only when objects were presented within reach. Findings demonstrate that competition between structural and functional affordances during object perception induces a processing cost, and further show that object position in space can bias affordance competition. Copyright © 2016 Elsevier B.V. All rights reserved.

46 CFR 108.187 - Ventilation for brush type electric motors in classified spaces.

Science.gov (United States)

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Ventilation for brush type electric motors in classified... Ventilation for brush type electric motors in classified spaces. Ventilation for brush type electric motors in... Electrical Equipment in Hazardous Locations”, except audible and visual alarms may be used if shutting down...

41 CFR 102-73.170 - What types of special purpose space may the Department of Agriculture lease?

Science.gov (United States)

2010-07-01

... purpose space may the Department of Agriculture lease? 102-73.170 Section 102-73.170 Public Contracts and... § 102-73.170 What types of special purpose space may the Department of Agriculture lease? The Department of Agriculture is delegated the authority to lease the following types of special purpose space: (a...

Mathematical aspects of the discrete space-time hypothesis

International Nuclear Information System (INIS)

Sardanashvili, G.A.

1979-01-01

A hypothesis of a microcosm space discreteness is considered from the theoretical-mathematical point of view. The type of topological spaces, which formalizes representations on the discrete space-time, is determined. It is explained, how these spaces arise in physical models. The physical task, in which the discrete space could arise as a version of its solution, is considered. It is shown that the discrete structure of space can arise with a certain interaction type in the system, for example, with its considerable self-shielding, which can take place, in particular, in the particles or in the cosmological and astrophysical singularities

Ross Works on the Assembly Concept for Construction of Erectable Space Structure (ACCESS) During

Science.gov (United States)

1985-01-01

The crew assigned to the STS-61B mission included Bryan D. O'Conner, pilot; Brewster H. Shaw, commander; Charles D. Walker, payload specialist; mission specialists Jerry L. Ross, Mary L. Cleave, and Sherwood C. Spring; and Rodolpho Neri Vela, payload specialist. Launched aboard the Space Shuttle Atlantis November 28, 1985 at 7:29:00 pm (EST), the STS-61B mission's primary payload included three communications satellites: MORELOS-B (Mexico); AUSSAT-2 (Australia); and SATCOM KU-2 (RCA Americom). Two experiments were conducted to test assembling erectable structures in space: EASE (Experimental Assembly of Structures in Extravehicular Activity), and ACCESS (Assembly Concept for Construction of Erectable Space Structure). In a joint venture between NASA/Langley Research Center in Hampton, Virginia, and the Marshall Space Flight Center (MSFC), EASE and ACCESS were developed and demonstrated at MSFC's Neutral Buoyancy Simulator (NBS). In this STS-61B onboard photo, astronaut Ross works on ACCESS high above the orbiter. The primary objective of these experiments was to test the structural assembly concepts for suitability as the framework for larger space structures and to identify ways to improve the productivity of space construction.

A function space framework for structural total variation regularization with applications in inverse problems

Science.gov (United States)

Hintermüller, Michael; Holler, Martin; Papafitsoros, Kostas

2018-06-01

In this work, we introduce a function space setting for a wide class of structural/weighted total variation (TV) regularization methods motivated by their applications in inverse problems. In particular, we consider a regularizer that is the appropriate lower semi-continuous envelope (relaxation) of a suitable TV type functional initially defined for sufficiently smooth functions. We study examples where this relaxation can be expressed explicitly, and we also provide refinements for weighted TV for a wide range of weights. Since an integral characterization of the relaxation in function space is, in general, not always available, we show that, for a rather general linear inverse problems setting, instead of the classical Tikhonov regularization problem, one can equivalently solve a saddle-point problem where no a priori knowledge of an explicit formulation of the structural TV functional is needed. In particular, motivated by concrete applications, we deduce corresponding results for linear inverse problems with norm and Poisson log-likelihood data discrepancy terms. Finally, we provide proof-of-concept numerical examples where we solve the saddle-point problem for weighted TV denoising as well as for MR guided PET image reconstruction.

Properties of Floquet-Bloch space harmonics in 1D periodic magneto-dielectric structures

DEFF Research Database (Denmark)

Breinbjerg, O.

2012-01-01

Recent years have witnessed a significant research interest in Floquet-Bloch analysis for determining the homogenized permittivity and permeability of metamaterials consisting of periodic structures. This work investigates fundamental properties of the Floquet-Bloch space harmonics in a 1......-dimensional magneto-dielectric lossless structure supporting a transverse-electric-magnetic Floquet-Bloch wave; in particular, the space harmonic permittivity and permeability, as well as the space harmonic Poynting vector....

Interspecies radioimmunoassay for the major structural proteins of primate type-D retroviruses

International Nuclear Information System (INIS)

Colcher, D.; Teramoto, Y.A.; Schlom, J.

1977-01-01

A competition radioimmunoassay has been developed in which type-D retroviruses from three primate species compete. The assay utilizes the major structural protein (36,000 daltons) of the endogenous squirrel monkey retrovirus and antisera directed against the major structural protein (27,000 daltons) of the Mason-Pfizer monkey virus isolated from rhesus monkeys. Purified preparations of both viruses grown in heterologous cells, as well as extracts of heterologous cells infected with squirrel monkey retrovirus or Mason-Pfizer monkey virus, compete completely in the assay. Addition of an endogenous virus of the langur monkey also results in complete blocking. No blocking in the assay is observed with type-C baboon viruses, woolly monkey virus, and gibbon virus. Various other type-C and type-B viruses also showed no reactivity. An interspecies assay has thus been developed that recognizes the type-D retroviruses from both Old World monkey (rhesus and langur) and New World monkey (squirrel) species

Secondary structure classification of amino-acid sequences using state-space modeling

OpenAIRE

Brunnert, Marcus; Krahnke, Tillmann; Urfer, Wolfgang

2001-01-01

The secondary structure classification of amino acid sequences can be carried out by a statistical analysis of sequence and structure data using state-space models. Aiming at this classification, a modified filter algorithm programmed in S is applied to data of three proteins. The application leads to correct classifications of two proteins even when using relatively simple estimation methods for the parameters of the state-space models. Furthermore, it has been shown that the assumed initial...

Emergence of a few distinct structures from a single formal structure type during high-throughput screening for stable compounds: The case of RbCuS and RbCuSe

Science.gov (United States)

Trimarchi, Giancarlo; Zhang, Xiuwen; DeVries Vermeer, Michael J.; Cantwell, Jacqueline; Poeppelmeier, Kenneth R.; Zunger, Alex

2015-10-01

Theoretical sorting of stable and synthesizable "missing compounds" from those that are unstable is a crucial step in the discovery of previously unknown functional materials. This active research area often involves high-throughput (HT) examination of the total energy of a given compound in a list of candidate formal structure types (FSTs), searching for those with the lowest energy within that list. While it is well appreciated that local relaxation methods based on a fixed list of structure types can lead to inaccurate geometries, this approach is widely used in HT studies because it produces answers faster than global optimization methods (that vary lattice vectors and atomic positions without local restrictions). We find, however, a different failure mode of the HT protocol: specific crystallographic classes of formal structure types each correspond to a series of chemically distinct "daughter structure types" (DSTs) that have the same space group but possess totally different local bonding configurations, including coordination types. Failure to include such DSTs in the fixed list of examined candidate structures used in contemporary high-throughput approaches can lead to qualitative misidentification of the stable bonding pattern, not just quantitative inaccuracies. In this work, we (i) clarify the understanding of the general DST-FST relationship, thus improving current discovery HT approaches, (ii) illustrate this failure mode for RbCuS and RbCuSe (the latter being a yet unreported compound and is predicted here) by developing a synthesis method and accelerated crystal-structure determination, and (iii) apply the genetic-algorithm-based global space-group optimization (GSGO) approach which is not vulnerable to the failure mode of HT searches of fixed lists, demonstrating a correct identification of the stable DST. The broad impact of items (i)-(iii) lies in the demonstrated predictive ability of a more comprehensive search strategy than what is currently

Schur spaces and weighted spaces of type H

African Journals Online (AJOL)

We extend some results related to composition operators on Hv(G) to arbitrary linear operators on Hv0 (G) and Hv(G). We also give examples of rank-one operators on Hv(G) which cannot be approximated by composition operators. Keywords: Weighted Banach spaces of holomorphic functions, Schur spaces, weakly ...

Space Shuttle Orbiter - Leading edge structural design/analysis and material allowables

Science.gov (United States)

Johnson, D. W.; Curry, D. M.; Kelly, R. E.

1986-01-01

Reinforced Carbon-Carbon (RCC), a structural composite whose development was targeted for the high temperature reentry environments of reusable space vehicles, has successfully demonstrated that capability on the Space Shuttle Orbiter. Unique mechanical properties, particularly at elevated temperatures up to 3000 F, make this material ideally suited for the 'hot' regions of multimission space vehicles. Design allowable characterization testing, full-scale development and qualification testing, and structural analysis techniques will be presented herein that briefly chart the history of the RCC material from infancy to eventual multimission certification for the Orbiter. Included are discussions pertaining to the development of the design allowable data base, manipulation of the test data into usable forms, and the analytical verification process.

Structural Design of Glass and Ceramic Components for Space System Safety

Science.gov (United States)

Bernstein, Karen S.

2007-01-01

Manned space flight programs will always have windows as part of the structural shell of the crew compartment. Astronauts and cosmonauts need to and enjoy looking out of the spacecraft windows at Earth, at approaching vehicles, at scientific objectives and at the stars. With few exceptions spacecraft windows have been made of glass, and the lessons learned over forty years of manned space flight have resulted in a well-defined approach for using this brittle, unforgiving material in NASA's vehicles, in windows and other structural applications. This chapter will outline the best practices that have developed at NASA for designing, verifying and accepting glass (and ceramic) windows and other components for safe and reliable use in any space system.

Imaging of the perivertebral space.

Science.gov (United States)

Mills, Megan K; Shah, Lubdha M

2015-01-01

The perivertebral space extends from the skull base to the mediastinum and is delineated by the deep layer of the deep cervical fascia. The different tissue types, including muscles, bones, nerves, and vascular structures, give rise to the various disorders that can be seen in this space. This article defines the anatomy of the perivertebral space, guides lesion localization, discusses different disease processes arising within this space, and reviews the best imaging approaches. Copyright © 2015 Elsevier Inc. All rights reserved.

Simulating Nonlinear Dynamics of Deployable Space Structures, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — To support NASA's vital interest in developing much larger solar array structures over the next 20 years, MotionPort LLC's Phase I SBIR project will strengthen...

Symmetries of nonrelativistic phase space and the structure of quark-lepton generation

International Nuclear Information System (INIS)

Zenczykowski, Piotr

2009-01-01

According to the Hamiltonian formalism, nonrelativistic phase space may be considered as an arena of physics, with momentum and position treated as independent variables. Invariance of x 2 + p 2 constitutes then a natural generalization of ordinary rotational invariance. We consider Dirac-like linearization of this form, with position and momentum satisfying standard commutation relations. This leads to the identification of a quantum-level structure from which some phase space properties might emerge. Genuine rotations and reflections in phase space are tied to the existence of new quantum numbers, unrelated to ordinary 3D space. Their properties allow their identification with the internal quantum numbers characterising the structure of a single quark-lepton generation in the Standard Model. In particular, the algebraic structure of the Harari-Shupe preon model of fundamental particles is reproduced exactly and without invoking any subparticles. Analysis of the Clifford algebra of nonrelativistic phase space singles out an element which might be associated with the concept of lepton mass. This element is transformed into a corresponding element for a single coloured quark, leading to a generalization of the concept of mass and a different starting point for the discussion of quark unobservability.

Coexistence of Cluster Structure and Mean-field-type Structure in Medium-weight Nuclei

International Nuclear Information System (INIS)

Taniguchi, Yasutaka; Horiuchi, Hisashi; Kimura, Masaaki

2006-01-01

We have studied the coexistence of cluster structure and mean-field-type structure in 20Ne and 40Ca using Antisymmetrized Molecular Dynamics (AMD) + Generator Coordinate Method (GCM). By energy variation with new constraint for clustering, we calculate cluster structure wave function. Superposing cluster structure wave functions and mean-field-type structure wave function, we found that 8Be-12C, α-36Ar and 12C-28Si cluster structure are important components of K π = 0 3 + band of 20Ne, that of normal deformed band of 40Ca and that of super deformed band of 40Ca, respectively

Role of Van Hove singularities and momentum-space structure in high-temperature superconductivity

International Nuclear Information System (INIS)

Radtke, R.J.; Levin, K.; Schuettler, H.; Norman, M.R.

1993-01-01

There is a great deal of interest in attributing the high critical temperatures of the cuprates to either the proximity of the Fermi level to a Van Hove singularity or to structure of the superconducting pairing potential in momentum space far from the Fermi surface; the latter is particularly important for spin-fluctuation-mediated pairing mechanisms. We examine these ideas by calculating the critical temperature T c for model Einstein-phonon- and spin-fluctuation-mediated superconductors within both the standard, Fermi-surface-restricted Eliashberg theory and the exact Eliashberg theory, which accounts for the full momentum structure of the pairing potential and the energy dependence of the density of states. Our computations employ band structures chosen to model both the La 2 Sr 2-x CuO 4 and YBa 2 Cu 3 O 7-δ families. For our spin fluctuation calculations, we take the dynamical susceptibility to be the pairing potential and examine two models of this susceptibility in the cuprates. We compare and contrast these models with available magnetic neutron-scattering data, since these data provide the most direct constraints on the susceptibility. We conclude that a model constrained by neutron-scattering measurements will not yield the observed 90-K T c 's regardless of the strength of the electron-spin fluctuation coupling, even when the Van Hove singularity and momentum-space structure are accounted for; moreover, when transport constraints are applied to this type of model, we expect T c ∼10 K, as was found in an earlier paper. We also find that the Van Hove singularity enhances T c much less effectively than weak-coupling calculations would suggest

Space-time structure and the origin of physical law

International Nuclear Information System (INIS)

Green, M.A.

1980-01-01

In the first part of this theses the author adopts a traditional world view, with space-time a topologically simple geometrical manifold, matter being represented by smooth classical fields, and space a Riemannian submanifold of space-time. It is shown how to characterize the space-time geometry in terms of fields defined on three-dimensional space. Accepting a finite number of the fields induced on space as independent initial data, a procedure is given for constructing dynamical and constraint equations which will propagate these fields forward in time. When the initial data are restricted to include only the hypersurface metric and the extrinsic curvature, the resulting equations combine to form the Einstein gravitational field equations with the cosmological term. The synthesis of gravitational and quantum physics is approached by proposing that the objective world underlying the perceived world is a four-dimensional topological manifold w, with no physically significant field structure and an unconstrianed and complex global topology. Conventional space-time is then a topologically simple replacement manifold for w. A preliminary outline of the correspondence is presented, based on a similarity between a natural graphical representation of 2 and the Feynman graphs of quantum field theory

Real-variable theory of Musielak-Orlicz Hardy spaces

CERN Document Server

Yang, Dachun; Ky, Luong Dang

2017-01-01

The main purpose of this book is to give a detailed and complete survey of recent progress related to the real-variable theory of Musielak–Orlicz Hardy-type function spaces, and to lay the foundations for further applications. The real-variable theory of function spaces has always been at the core of harmonic analysis. Recently, motivated by certain questions in analysis, some more general Musielak–Orlicz Hardy-type function spaces were introduced. These spaces are defined via growth functions which may vary in both the spatial variable and the growth variable. By selecting special growth functions, the resulting spaces may have subtler and finer structures, which are necessary in order to solve various endpoint or sharp problems. This book is written for graduate students and researchers interested in function spaces and, in particular, Hardy-type spaces.

Infrared Fibers for Use in Space-Based Smart Structures

Science.gov (United States)

Tucker, Dennis S.; Nettles, Alan T.; Brantley, Lott W. (Technical Monitor)

2001-01-01

Infrared optical fibers are finding a number of applications including laser surgery, remote sensing, and nuclear radiation resistant links. Utilizing these fibers in space-based structures is another application, which can be exploited. Acoustic and thermal sensing are two areas in which these fibers could be utilized. In particular, fibers could be embedded in IM7/8552 toughened epoxy and incorporated into space structures both external and internal. ZBLAN optical fibers are a candidate, which have been studied extensively over the past 20 years for terrestrial applications. For the past seven years the effects of gravity on the crystallization behavior of ZBLAN optical fiber has been studied. It has been found that ZBLAN crystallization is suppressed in microgravity. This lack of crystallization leads to a fiber with better transmission characteristics than its terrestrial counterpart.

Laboratory science with space data accessing and using space-experiment data

CERN Document Server

van Loon, Jack J W A; Zell, Martin; Beysens, Daniel

2011-01-01

For decades experiments conducted on space stations like MIR and the ISS have been gathering data in many fields of research in the natural sciences, medicine and engineering. The European Union-sponsored ULISSE project focused on exploring the wealth of unique experimental data provided by revealing raw and metadata from these studies via an Internet Portal. This book complements the portal. It serves as a handbook of space experiments and describes the various types of experimental infrastructure areas of research in the life and physical sciences and technology space missions that hosted scientific experiments the types and structures of the data produced and how one can access the data through ULISSE for further research. The book provides an overview of the wealth of space experiment data that can be used for additional research and will inspire academics (e.g. those looking for topics for their PhD thesis) and research departments in companies for their continued development.

Nucleon structure functions in noncommutative space-time

Energy Technology Data Exchange (ETDEWEB)

Rafiei, A.; Rezaei, Z.; Mirjalili, A. [Yazd University, Physics Department, Yazd (Iran, Islamic Republic of)

2017-05-15

In the context of noncommutative space-time we investigate the nucleon structure functions which play an important role in identifying the internal structure of nucleons. We use the corrected vertices and employ new vertices that appear in two approaches of noncommutativity and calculate the proton structure functions in terms of the noncommutative tensor θ{sub μν}. To check our results we plot the nucleon structure function (NSF), F{sub 2}(x), and compare it with experimental data and the results from the GRV, GJR and CT10 parametrization models. We show that with the new vertex that arises the noncommutativity correction will lead to a better consistency between theoretical results and experimental data for the NSF. This consistency will be better for small values of the Bjorken variable x. To indicate and confirm the validity of our calculations we also act conversely. We obtain a lower bound for the numerical values of Λ{sub NC} scale which correspond to recent reports. (orig.)

Spatial analysis of various multiplex cinema types

Directory of Open Access Journals (Sweden)

Young-Seo Park

2016-03-01

Full Text Available This study identifies the spatial characteristics and relationships of each used space according to the multiplex type. In this study, multiplexes are classified according to screen rooms and circulation systems, and each used space is quantitatively analyzed. The multiplex type based on screen rooms and moving line systems influences the relationship and characteristics of each used space in various ways. In particular, the structure of the used space of multiplexes has a significant effect on profit generation and audience convenience.

The distribution function of a probability measure on a space with a fractal structure

Energy Technology Data Exchange (ETDEWEB)

Sanchez-Granero, M.A.; Galvez-Rodriguez, J.F.

2017-07-01

In this work we show how to define a probability measure with the help of a fractal structure. One of the keys of this approach is to use the completion of the fractal structure. Then we use the theory of a cumulative distribution function on a Polish ultrametric space and describe it in this context. Finally, with the help of fractal structures, we prove that a function satisfying the properties of a cumulative distribution function on a Polish ultrametric space is a cumulative distribution function with respect to some probability measure on the space. (Author)

Optimal control of large space structures via generalized inverse matrix

Science.gov (United States)

Nguyen, Charles C.; Fang, Xiaowen

1987-01-01

Independent Modal Space Control (IMSC) is a control scheme that decouples the space structure into n independent second-order subsystems according to n controlled modes and controls each mode independently. It is well-known that the IMSC eliminates control and observation spillover caused when the conventional coupled modal control scheme is employed. The independent control of each mode requires that the number of actuators be equal to the number of modelled modes, which is very high for a faithful modeling of large space structures. A control scheme is proposed that allows one to use a reduced number of actuators to control all modeled modes suboptimally. In particular, the method of generalized inverse matrices is employed to implement the actuators such that the eigenvalues of the closed-loop system are as closed as possible to those specified by the optimal IMSC. Computer simulation of the proposed control scheme on a simply supported beam is given.

A sodium gadolinium phosphate with two different types of tunnel structure: Synthesis, crystal structure, and optical properties of Na3GdP2O8

International Nuclear Information System (INIS)

Fang, M.; Cheng, W.-D.; Zhang, H.; Zhao, D.; Zhang, W.-L.; Yang, S.-L.

2008-01-01

A sodium gadolinium phosphate crystal, Na 3 GdP 2 O 8 , has been synthesized by a high-temperature solution reaction, and it exhibits a new structural family of the alkali-metal-rare-earth phosphate system. Although many compounds with formula M 3 LnP 2 O 8 have been reported, but they were shown to be orthorhombic [R. Salmon, C. Parent, M. Vlasse, G. LeFlem, Mater. Res. Bull. 13 (1978) 439] rather than monoclinic as shown in this paper. Single-crystal X-ray diffraction analysis shows the structure to be monoclinic with space group C2/c and the cell parameters: a=27.55 (25), b=5.312 (4), c=13.935(11) A, β=91.30(1) o , and V=2038.80 A 3 , Z=4. Its structure features a three-dimensional GdP 2 O 8 3- anionic framework with two different types of interesting tunnels at where Na atoms are located by different manners. The framework is constructed by Gd polyhedra and isolated PO 4 tetrahedra. It is different from the structure of K 3 NdP 2 O 8 [R. Salmon, C. Parent, M. Vlasse, G. LeFlem, Mater. Res. Bull. 13 (1978) 439] with space group P2 1 /m that shows only one type of tunnel. The emission spectrum and the absorption spectrum of the compound have been investigated. Additionally, the calculations of band structure, density of states, dielectric constants, and refractive indexes have been also performed with the density functional theory method. The obtained results tend to support the experimental data. - Graphical abstract: Projection of the structure of Na 3 GdP 2 O 8 with a unit cell edge along the b-axis. The Na-O bonds are omitted for clarity

Green's functions in Bianchi type-I spaces. Relation between Minkowski and Euclidean approaches

International Nuclear Information System (INIS)

Bukhbinder, I.L.; Kirillova, E.N.

1988-01-01

A theory is considered for a free scalar field with a conformal connection in a curved space-time with a Bianchi type-I metric. A representation is obtained for the Green's function G∼ in in in the form of an integral of a Schwinger-DeWitt kernel along a contour in a plane of complex-valued proper time. It is shown how as transition may be accomplished from Green's functions in space with the Euclidean signature to Green's functions in space with Minkowski signature and vice versa

STS-61B Astronaut Ross Works on Assembly Concept for Construction of Erectable Space Structure

Science.gov (United States)

1985-01-01

The crew assigned to the STS-61B mission included Bryan D. O'Conner, pilot; Brewster H. Shaw, commander; Charles D. Walker, payload specialist; mission specialists Jerry L. Ross, Mary L. Cleave, and Sherwood C. Spring; and Rodolpho Neri Vela, payload specialist. Launched aboard the Space Shuttle Atlantis November 28, 1985 at 7:29:00 pm (EST), the STS-61B mission's primary payload included three communications satellites: MORELOS-B (Mexico); AUSSAT-2 (Australia); and SATCOM KU-2 (RCA Americom). Two experiments were conducted to test assembling erectable structures in space: EASE (Experimental Assembly of Structures in Extravehicular Activity), and ACCESS (Assembly Concept for Construction of Erectable Space Structure). In a joint venture between NASA/Langley Research Center in Hampton, Virginia and the Marshall Space Flight Center (MSFC), EASE and ACCESS were developed and demonstrated at MSFC's Neutral Buoyancy Simulator (NBS). In this STS-61B onboard photo astronaut Ross, located on the Manipulator Foot Restraint (MFR) over the cargo bay, erects ACCESS. The primary objective of this experiment was to test the structural assembly concepts for suitability as the framework for larger space structures and to identify ways to improve the productivity of space construction.

Large Format LW Type-II SLS FPAs for Space Applications, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This Phase I SBIR proposes to develop high performance (low dark current, high quantum efficiency, and low NEdT) infrared epitaxy materials based on Type II Strained...

Differential calculi on quantum vector spaces with Hecke-type relations

International Nuclear Information System (INIS)

Baez, J.C.

1991-01-01

From a vector space V equipped with a Yang-Baxter operator R one may form the r-symmetric algebra S R V=TV/ , which is a quantum vector space in the sense of Manin, and the associated quantum matrix algebra M R V=T(End(V))/ -1 >. In the case when R satisfies a Hecke-type identity R 2 =(1-q)R+q, we construct a differential calculus Ω R V for S R V which agrees with that constructed by Pusz, Woronowicz, Wess, and Zumino when R is essentially the R-matrix of GL q (n). Elements of Ω R V may be regarded as differential forms on the quantum vector space S R V. We show that Ω R V is M R V-covariant in the sense that there is a coaction Φ * :Ω R V→M R VxΩ R V with Φ * d=(1xd)Φ * extending the natural coaction Φ:S R V→M R VxS R V. (orig.)

On the structure of the space of geometric product-form models

NARCIS (Netherlands)

Bayer, Nimrod; Boucherie, Richardus J.

2002-01-01

This article deals with Markovian models defined on a finite-dimensional discrete state space and possess a stationary state distribution of a product-form. We view the space of such models as a mathematical object and explore its structure. We focus on models on an orthant [script Z]+n, which are

New tetragonal derivatives of cubic NaZn{sub 13}-type structure: RNi{sub 6}Si{sub 6} compounds, crystal structure and magnetic ordering (R=Y, La, Ce, Sm, Gd–Yb)

Energy Technology Data Exchange (ETDEWEB)

Pani, M.; Manfrinetti, P.; Provino, A. [INFM and Dipartimento di Chimica e Chimica Industriale, Universita‘ di Genova, Via Dodecaneso 31, 16146 Genova (Italy); Yuan, Fang; Mozharivskyj, Y. [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, ON, Canada L8S 4M1 (Canada); Morozkin, A.V., E-mail: morozkin@general.chem.msu.ru [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Knotko, A.V.; Garshev, A.V. [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Yapaskurt, V.O. [Department of Petrology, Geological Faculty, Moscow State University, Leninskie Gory, Moscow 119992 (Russian Federation); Isnard, O. [Université Grenoble Alpes, Inst NEEL, BP166, F-38042 Grenoble (France); CNRS, Institut NEEL, 25 rue des martyrs, F-38042 Grenoble (France)

2014-02-15

Novel RNi{sub 6}Si{sub 6} compounds adopt the new CeNi{sub 6}Si{sub 6}-type structure for R=La–Ce (tP52, space group P4/nbm N 125-1) and new YNi{sub 6}Si{sub 6}-type structure for R=Y, Sm, Gd–Yb (tP52, space group P4{sup ¯}b2N 117) that are tetragonal derivative of NaZn{sub 13}-type structure, like LaCo{sub 9}Si{sub 4}-type. The CeNi{sub 6}Si{sub 6}, GdNi{sub 6}Si{sub 6}, TbNi{sub 6}Si{sub 6}, DyNi{sub 6}Si{sub 6} and HoNi{sub 6}Si{sub 6} compounds are Curie–Weiss paramagnets down to ∼30 K, and do not order magnetically down to 5 K. However, the inverse paramagnetic susceptibility of LaNi{sub 6}Si{sub 6} does not follow Curie–Weiss law. The DyNi{sub 6}Si{sub 6} shows ferromagnetic-like saturation behaviour at 5 K in applied fields of 50 kOe, giving rise to a magnetic moment value of 6.5 μ{sub B}/f.u. in 50 kOe. The powder neutron diffraction study in zero applied filed indicates square modulated the c-collinear antiferromagnetic ordering of TbNi{sub 6}Si{sub 6} with K=[±1/4, ±1/4, 0] wave vector below ∼10 K. - Graphical abstract: Novel (La, Ce)Ni{sub 6}Si{sub 6} compounds adopt the new CeNi{sub 6}Si{sub 6}-type structure and (Y, Sm, Gd–Yb) adopt the new YNi{sub 6}Si{sub 6}-type structure that are tetragonal derivative of NaZn{sub 13}-type structure, like LaCo{sub 9}Si{sub 4}-type. The CeNi{sub 6}Si{sub 6}, GdNi{sub 6}Si{sub 6}, TbNi{sub 6}Si{sub 6}, DyNi{sub 6}Si{sub 6} and HoNi{sub 6}Si{sub 6} compounds are Curie–Weiss paramagnets down to ∼30 K, and do not order magnetically down to 4.2 K. The powder neutron diffraction study in zero applied filed indicates square modulated the c-collinear antiferromagnetic ordering of TbNi{sub 6}Si{sub 6} with K=[±1/4, ±1/4, 0] wave vector below ∼10 K. Display Omitted - Highlights: • The new (La, Ce)Ni{sub 6}Si{sub 6} compounds adopt the new CeNi{sub 6}Si{sub 6}-type structure. • The new (Y, Sm, Gd–Yb)Ni{sub 6}Si{sub 6} compounds adopt the new YNi{sub 6}Si{sub 6}-type structure. • TbNi{sub 6}Si

On zeros of some analytic spaces of area Nevanlinna type in halfplane

Directory of Open Access Journals (Sweden)

Shamoyan R. F.

2010-01-01

Full Text Available We introduce two new scales of spaces of Nevanlinna type in a halfplane C+ and provide descriptions of their zero sets and based on it we present parametric representations of these classes.

High-Resolution Reciprocal Space Mapping for Characterizing Deformation Structures

DEFF Research Database (Denmark)

Pantleon, Wolfgang; Wejdemann, Christian; Jakobsen, Bo

2014-01-01

With high-angular resolution three-dimensional X-ray diffraction (3DXRD), quantitative information is gained about dislocation structures in individual grains in the bulk of a macroscopic specimen by acquiring reciprocal space maps. In high-resolution 3D reciprocal space maps of tensile......-deformed copper, individual, almost dislocation-free subgrains are identified from high-intensity peaks and distinguished by their unique combination of orientation and elastic strain; dislocation walls manifest themselves as a smooth cloud of lower intensity. The elastic strain shows only minor variations within...... dynamics is followed in situ during varying loading conditions by reciprocal space mapping: during uninterrupted tensile deformation, formation of subgrains is observed concurrently with broadening of Bragg reflections shortly after the onset of plastic deformation. When the traction is terminated, stress...

Multipactor suppression by micro-structured gold/silver coatings for space applications

Science.gov (United States)

Nistor, Valentin; González, Luis A.; Aguilera, Lydya; Montero, Isabel; Galán, Luis; Wochner, Ulrich; Raboso, David

2014-10-01

The secondary electron emission (SEE) from materials used in high power RF devices in space is the main trigger and sustaining mechanism of the resonant avalanche electron discharge known as the multipactor effect. It limits the attainable power of those devices. During recent decades, some scientific research has been focused on material properties for obtaining anti-multipactor coatings of low secondary emission yield (SEY). The European Space Agency (ESA) is leading a technological research on a new approach based on surface roughness that might perform as a kind of blackbody or Faraday cage effect. A multilayer coating structure was adopted for fulfilling the stringent requirements of the space. The surface of a standard silver plating was modified by a two-step treatment. First, a wet chemically etching process created a roughness of high aspect ratio, in the scale of microns. Secondly, the surface was coated with a protective 2 μm overlayer of gold, using magnetron sputtering. This anti-multipactor coating has been tested on several types of Ku-band WR75 waveguide transformers and band-pass filters, with excellent results. The multipactor effect was suppressed for two waveguides, even when applying the maximum available power levels. As for the other final four, the increase of multipactor power level was in the range of 4-6 dB. These results were obtained after more than one year of air exposure. In spite of the strong roughness, the insertion losses were diminished by 25% with respect to the values attained in the tests of the standard anti-multipactor coating, Alodine.

Ceramic materials on perovskite-type structure for electronic applications

International Nuclear Information System (INIS)

Surowiak, Z.

2003-01-01

Ceramic materials exhibiting the perovskite-type structure constitute among others, resource base for many fields of widely understood electronics (i.e., piezoelectronics, accustoelectronics, optoelectronics, computer science, tele- and radioelectronics etc.). Most often they are used for fabrication of different type sensors (detectors), transducers, ferroelectric memories, limiters of the electronic current intensity, etc., and hence they are numbered among so-called intelligent materials. Prototype structure of this group of materials is the structure of the mineral called perovskite (CaTiO 3 ). By means of right choice of the chemical composition of ABO 3 and deforming the regular perovskite structure (m3m) more than 5000 different chemical compounds and solid solutions exhibiting the perovskite-type structure have been fabricated. The concept of perovskite functional ceramics among often things ferroelectric ceramics, pyroelectric ceramics, piezoelectric ceramics, electrostrictive ceramics, posistor ceramics, superconductive ceramics and ferromagnetic ceramics. New possibilities of application of the perovskite-type ceramics are opened by nanotechnology. (author)

Effect of annealing temperature on the structural, photoluminescence and magnetic properties of sol-gel derived Magnetoplumbite-type (M-type) hexagonal strontium ferrite

International Nuclear Information System (INIS)

Teh, Geok Bee; Wong, Yat Choy; Tilley, Richard D.

2011-01-01

Magnetoplumbite-type (M-type) hexagonal strontium ferrite particles were synthesized via sol-gel technique employing ethylene glycol as the gel precursor at two different calcination temperatures (800 and 1000 deg. C). Structural properties were systematically investigated via X-ray diffraction (XRD), field emission scanning electron microscopy, high resolution transmission electron microscopy (HRTEM), energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), photoluminescence spectrophotometry and superconducting quantum interference device magnetometer. XRD results showed that the sample synthesized at 1000 deg. C was of single-phase with a space group of P6 3 /mmc and lattice cell parameter values of a=5.882 A and c=23.048 A. EDS confirmed the composition of strontium ferrite calcined at 1000 deg. C being mainly of M-type SrFe 12 O 19 with HRTEM micrographs confirming the ferrites exhibiting M-type long range ordering along the c-axis of the crystal structure. The photoluminescence (PL) property of strontium ferrite was examined at excitation wavelengths of 260 and 270 nm with significant PL emission peaks centered at 350 nm being detected. Strontium ferrite annealed at higher temperature (1000 deg. C) was found to have grown into larger particle size, having higher content of oxygen vacancies and exhibited 83-85% more intense PL. Both the as-prepared strontium ferrites exhibited significant oxygen vacancies defect structures, which were verified via TGA. Higher calcination temperature turned strontium ferrite into a softer ferrite. - Highlights: → High annealing temperature produced M-type ferrite with higher oxygen vacancies. → Photoluminescence intensity is proportional to the existence of oxygen vacancies. → XRD data showed cell contraction well suited to the change of oxygen vacancies. → Shift in hysteresis loop due to defect-induced exchange bias was observed.

Effect of annealing temperature on the structural, photoluminescence and magnetic properties of sol-gel derived Magnetoplumbite-type (M-type) hexagonal strontium ferrite

Energy Technology Data Exchange (ETDEWEB)

Teh, Geok Bee, E-mail: sharonteh2009@gmail.com [Division of Bioscience and Chemistry, School of Arts and Science, Tunku Abdul Rahman College, Jalan Genting Kelang, 53300 Kuala Lumpur (Malaysia); Wong, Yat Choy [Faculty of Engineering and Industrial Sciences, Swinburne University of Technology, PO Box 218, Hawthorn, Victoria 3122 (Australia); Tilley, Richard D. [School of Chemical and Physical Sciences, MacDiarmid Institute of Advanced Materials and Nanotechnology, Victoria University of Wellington, PO Box 600, Wellington (New Zealand)

2011-09-15

Magnetoplumbite-type (M-type) hexagonal strontium ferrite particles were synthesized via sol-gel technique employing ethylene glycol as the gel precursor at two different calcination temperatures (800 and 1000 deg. C). Structural properties were systematically investigated via X-ray diffraction (XRD), field emission scanning electron microscopy, high resolution transmission electron microscopy (HRTEM), energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), photoluminescence spectrophotometry and superconducting quantum interference device magnetometer. XRD results showed that the sample synthesized at 1000 deg. C was of single-phase with a space group of P6{sub 3}/mmc and lattice cell parameter values of a=5.882 A and c=23.048 A. EDS confirmed the composition of strontium ferrite calcined at 1000 deg. C being mainly of M-type SrFe{sub 12}O{sub 19} with HRTEM micrographs confirming the ferrites exhibiting M-type long range ordering along the c-axis of the crystal structure. The photoluminescence (PL) property of strontium ferrite was examined at excitation wavelengths of 260 and 270 nm with significant PL emission peaks centered at 350 nm being detected. Strontium ferrite annealed at higher temperature (1000 deg. C) was found to have grown into larger particle size, having higher content of oxygen vacancies and exhibited 83-85% more intense PL. Both the as-prepared strontium ferrites exhibited significant oxygen vacancies defect structures, which were verified via TGA. Higher calcination temperature turned strontium ferrite into a softer ferrite. - Highlights: > High annealing temperature produced M-type ferrite with higher oxygen vacancies. > Photoluminescence intensity is proportional to the existence of oxygen vacancies. > XRD data showed cell contraction well suited to the change of oxygen vacancies. > Shift in hysteresis loop due to defect-induced exchange bias was observed.

Hamiltonian flow over saddles for exploring molecular phase space structures

Science.gov (United States)

Farantos, Stavros C.

2018-03-01

Despite using potential energy surfaces, multivariable functions on molecular configuration space, to comprehend chemical dynamics for decades, the real happenings in molecules occur in phase space, in which the states of a classical dynamical system are completely determined by the coordinates and their conjugate momenta. Theoretical and numerical results are presented, employing alanine dipeptide as a model system, to support the view that geometrical structures in phase space dictate the dynamics of molecules, the fingerprints of which are traced by following the Hamiltonian flow above saddles. By properly selecting initial conditions in alanine dipeptide, we have found internally free rotor trajectories the existence of which can only be justified in a phase space perspective. This article is part of the theme issue `Modern theoretical chemistry'.

Laurent series expansion of sunrise-type diagrams using configuration space techniques

International Nuclear Information System (INIS)

Groote, S.; Koerner, J.G.; Pivovarov, A.A.

2004-01-01

We show that configuration space techniques can be used to efficiently calculate the complete Laurent series ε-expansion of sunrise-type diagrams to any loop order in D-dimensional space-time for any external momentum and for arbitrary mass configurations. For negative powers of ε the results are obtained in analytical form. For positive powers of ε including the finite ε 0 contribution the result is obtained numerically in terms of low-dimensional integrals. We present general features of the calculation and provide exemplary results up to five-loop order which are compared to available results in the literature. (orig.)

Coherent Structures and Spectral Energy Transfer in Turbulent Plasma: A Space-Filter Approach

Science.gov (United States)

Camporeale, E.; Sorriso-Valvo, L.; Califano, F.; Retinò, A.

2018-03-01

Plasma turbulence at scales of the order of the ion inertial length is mediated by several mechanisms, including linear wave damping, magnetic reconnection, the formation and dissipation of thin current sheets, and stochastic heating. It is now understood that the presence of localized coherent structures enhances the dissipation channels and the kinetic features of the plasma. However, no formal way of quantifying the relationship between scale-to-scale energy transfer and the presence of spatial structures has been presented so far. In the Letter we quantify such a relationship analyzing the results of a two-dimensional high-resolution Hall magnetohydrodynamic simulation. In particular, we employ the technique of space filtering to derive a spectral energy flux term which defines, in any point of the computational domain, the signed flux of spectral energy across a given wave number. The characterization of coherent structures is performed by means of a traditional two-dimensional wavelet transformation. By studying the correlation between the spectral energy flux and the wavelet amplitude, we demonstrate the strong relationship between scale-to-scale transfer and coherent structures. Furthermore, by conditioning one quantity with respect to the other, we are able for the first time to quantify the inhomogeneity of the turbulence cascade induced by topological structures in the magnetic field. Taking into account the low space-filling factor of coherent structures (i.e., they cover a small portion of space), it emerges that 80% of the spectral energy transfer (both in the direct and inverse cascade directions) is localized in about 50% of space, and 50% of the energy transfer is localized in only 25% of space.

An oxotantalate with network-type structure: Cs3Ta5O14

International Nuclear Information System (INIS)

Serafin, M.; Hoppe, R.

1982-01-01

Cs 3 Ta 5 O 14 was obtained for the first time as colourless single crystals, orthorhombic, a = 26.235(2), b = 7.429(1), c = 7.388(1) A, Z = 4, space group Pbam. According to four-circle-diffractometer data (1521 hkl, F 0 > 1.5 σ(F 0 ), 3 0 0 , R = 10%) it crystallizes with a complicated network-type structure. Ta is partly in an octahedral (C.N.6), partly in a trigonal-bipyramidal (C.N.5) environment. The [Ta 5 O 14 ] network contains channels occupied by Cs. Effective Coordination Numbers, ECoN, and the Madelung Part of the Lattice Energy, MAPLE, have been calculated and are discussed. (author)

Condition Based Maintenance of Space Exploration Vehicles Using Structural Health Monitoring, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Acellent Technologies proposes to develop an autonomous and automated diagnostic system for condition based maintenance (CBM) of safety critical structures for space...

Action detection by double hierarchical multi-structure space-time statistical matching model

Science.gov (United States)

Han, Jing; Zhu, Junwei; Cui, Yiyin; Bai, Lianfa; Yue, Jiang

2018-03-01

Aimed at the complex information in videos and low detection efficiency, an actions detection model based on neighboring Gaussian structure and 3D LARK features is put forward. We exploit a double hierarchical multi-structure space-time statistical matching model (DMSM) in temporal action localization. First, a neighboring Gaussian structure is presented to describe the multi-scale structural relationship. Then, a space-time statistical matching method is proposed to achieve two similarity matrices on both large and small scales, which combines double hierarchical structural constraints in model by both the neighboring Gaussian structure and the 3D LARK local structure. Finally, the double hierarchical similarity is fused and analyzed to detect actions. Besides, the multi-scale composite template extends the model application into multi-view. Experimental results of DMSM on the complex visual tracker benchmark data sets and THUMOS 2014 data sets show the promising performance. Compared with other state-of-the-art algorithm, DMSM achieves superior performances.

Phase space interrogation of the empirical response modes for seismically excited structures

Science.gov (United States)

Paul, Bibhas; George, Riya C.; Mishra, Sudib K.

2017-07-01

Conventional Phase Space Interrogation (PSI) for structural damage assessment relies on exciting the structure with low dimensional chaotic waveform, thereby, significantly limiting their applicability to large structures. The PSI technique is presently extended for structure subjected to seismic excitations. The high dimensionality of the phase space for seismic response(s) are overcome by the Empirical Mode Decomposition (EMD), decomposing the responses to a number of intrinsic low dimensional oscillatory modes, referred as Intrinsic Mode Functions (IMFs). Along with their low dimensionality, a few IMFs, retain sufficient information of the system dynamics to reflect the damage induced changes. The mutually conflicting nature of low-dimensionality and the sufficiency of dynamic information are taken care by the optimal choice of the IMF(s), which is shown to be the third/fourth IMFs. The optimal IMF(s) are employed for the reconstruction of the Phase space attractor following Taken's embedding theorem. The widely referred Changes in Phase Space Topology (CPST) feature is then employed on these Phase portrait(s) to derive the damage sensitive feature, referred as the CPST of the IMFs (CPST-IMF). The legitimacy of the CPST-IMF is established as a damage sensitive feature by assessing its variation with a number of damage scenarios benchmarked in the IASC-ASCE building. The damage localization capability, remarkable tolerance to noise contamination and the robustness under different seismic excitations of the feature are demonstrated.

Multivariate time series with linear state space structure

CERN Document Server

Gómez, Víctor

2016-01-01

This book presents a comprehensive study of multivariate time series with linear state space structure. The emphasis is put on both the clarity of the theoretical concepts and on efficient algorithms for implementing the theory. In particular, it investigates the relationship between VARMA and state space models, including canonical forms. It also highlights the relationship between Wiener-Kolmogorov and Kalman filtering both with an infinite and a finite sample. The strength of the book also lies in the numerous algorithms included for state space models that take advantage of the recursive nature of the models. Many of these algorithms can be made robust, fast, reliable and efficient. The book is accompanied by a MATLAB package called SSMMATLAB and a webpage presenting implemented algorithms with many examples and case studies. Though it lays a solid theoretical foundation, the book also focuses on practical application, and includes exercises in each chapter. It is intended for researchers and students wor...

Space structures, power, and power conditioning; Proceedings of the Meeting, Los Angeles, CA, Jan. 11-13, 1988

International Nuclear Information System (INIS)

Askew, R.F.

1988-01-01

Various papers on space structures, power, and power conditioning are presented. Among the topics discussed are: heterogeneous gas core reaction for space nuclear power, pulsed gas core reactor for burst power, fundamental considerations of gas core reactor systems, oscillating thermionic conversion for high-density space power, thermoelectromagnetic pumps for space nuclear power systems, lightweight electrochemical converter for space power applications, ballistic acceleration by superheated hydrogen, laser-induced current switching in gaseous discharge, electron-beam-controlled semiconductor switches, laser-controlled semiconductor closing and opening switch. Also addressed are: semiconductor-metal eutectic composites for high-power switching, optical probes for the characterization of surface breakdown, 40 kV/20 kA pseudospark switch for laser applications, insulation direction for high-power space systems, state space simulation of spacecraft power systems, structural vibration of space power station systems, minimum-time control of large space structures, novel fusion reaction for space power and propulsion, repetition rate system evaluations, cryogenic silicon photoconductive switches for high-power lasers, multilevel diamondlike carbon capacitor structure, surface breakdown of prestressed insulators, C-Mo and C-Zr alloys for space power systems, magnetic insulation for the space environment

Structural alphabets derived from attractors in conformational space

Directory of Open Access Journals (Sweden)

Kleinjung Jens

2010-02-01

Full Text Available Abstract Background The hierarchical and partially redundant nature of protein structures justifies the definition of frequently occurring conformations of short fragments as 'states'. Collections of selected representatives for these states define Structural Alphabets, describing the most typical local conformations within protein structures. These alphabets form a bridge between the string-oriented methods of sequence analysis and the coordinate-oriented methods of protein structure analysis. Results A Structural Alphabet has been derived by clustering all four-residue fragments of a high-resolution subset of the protein data bank and extracting the high-density states as representative conformational states. Each fragment is uniquely defined by a set of three independent angles corresponding to its degrees of freedom, capturing in simple and intuitive terms the properties of the conformational space. The fragments of the Structural Alphabet are equivalent to the conformational attractors and therefore yield a most informative encoding of proteins. Proteins can be reconstructed within the experimental uncertainty in structure determination and ensembles of structures can be encoded with accuracy and robustness. Conclusions The density-based Structural Alphabet provides a novel tool to describe local conformations and it is specifically suitable for application in studies of protein dynamics.

Heat transfer performance of multi-layer insulation structure under roof-slab of pool-type LMFBR

International Nuclear Information System (INIS)

Kinoshita, I.; Yoshida, K.; Uotani, M.; Fukada, T.

1988-01-01

At the normal operation of the pool-type LMFBR, the free surface of liquid sodium at about 500 0 C is present below the roof-slab, separated by a space of the argon cover gas. The temperature of the roof-slab has to be maintained low and uniform in the horizontal direction for sufficient strength of the structure. Therefore, thermal insulation structures must be installed on the lower surface of the roof-slab. In addition to the installation of thermal insulator, forced cooling of the roof-slab is required for assured structural integrity of the roof-slab. The capacity of cooling equipment can be reduced by installation of structures with high thermal insulating performance. The objective of this study is to evaluate the thermal insulation characteristics of multi-layer type insulator installed below the roof-slab by analytically and experimentally. The analytical study is intended to evaluate the effect of number, distance and emissivity of layers on the heat transfer performances. This is treated as the one-dimensional heat transfer with natural convection, conduction and thermal radiation. In the experiments, we have evaluated effects of gap distances between adjacent thermal insulators placed below the roof-slab on the thermal insulation performances

Tsirelson's space

CERN Document Server

Casazza, Peter G

1989-01-01

This monograph provides a structure theory for the increasingly important Banach space discovered by B.S. Tsirelson. The basic construction should be accessible to graduate students of functional analysis with a knowledge of the theory of Schauder bases, while topics of a more advanced nature are presented for the specialist. Bounded linear operators are studied through the use of finite-dimensional decompositions, and complemented subspaces are studied at length. A myriad of variant constructions are presented and explored, while open questions are broached in almost every chapter. Two appendices are attached: one dealing with a computer program which computes norms of finitely-supported vectors, while the other surveys recent work on weak Hilbert spaces (where a Tsirelson-type space provides an example).

New orthorhombic derivative of CaCu{sub 5}-type structure: RNi{sub 4}Si compounds (R=Y, La, Ce, Sm, Gd–Ho), crystal structure and some magnetic properties

Energy Technology Data Exchange (ETDEWEB)

Morozkin, A.V., E-mail: morozkin@general.chem.msu.ru [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Knotko, A.V. [Department of Chemistry, Moscow State University, Leninskie Gory, House 1, Building 3, GSP-2, Moscow 119992 (Russian Federation); Yapaskurt, V.O. [Department of Petrology, Geological Faculty, Moscow State University, Leninskie Gory, Moscow 119992 (Russian Federation); Yuan, Fang; Mozharivskyj, Y. [Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario, Canada L8S 4M1 (Canada); Nirmala, R. [Indian Institute of Technology Madras, Chennai 600036 (India)

2013-12-15

The crystal structure of new YNi{sub 4}Si-type RNi{sub 4}Si (R=Y, La, Ce, Sm, Gd–Ho) compounds has been established using powder X-ray diffraction. The YNi{sub 4}Si structure is a new structure type, which is orthorhombic derivative of CaCu{sub 5}-type structure (space group Cmmm N 65, oC12). GdNi{sub 4}Si and DyNi{sub 4}Si compounds order ferromagnetically at 25 and 19 K, respectively whereas YNi{sub 4}Si shows antiferromagnetic nature. At 15 K, DyNi{sub 4}Si shows second antiferromagnetic-like transition. The magnetic moment of GdNi{sub 4}Si at 5 K in 50 kOe field is ∼7.2 μ{sub B}/f.u. suggesting a completely ordered ferromagnetic state. The magnetocaloric effect of GdNi{sub 4}Si is calculated in terms of isothermal magnetic entropy change and it reaches the maximum value of −12.8 J/kg K for a field change of 50 kOe near T{sub C} ∼25 K. - Graphical abstract: The RNi{sub 4}Si (R=Y, La, Ce, Sm, Gd–Ho) compounds crystallize in new YNi{sub 4}Si-type structure which is orthorhombic derivative of the basic CaCu{sub 5}-type structure. GdNi{sub 4}Si and DyNi{sub 4}Si compounds show the ferromagnetic-like ordering, whereas.YNi{sub 4}Si has the antiferromagnetic nature. The GdNi{sub 4}Si demonstrates the big magnetocaloric effect near temperature of ferromagnetic ordering. The relationship between initial CaCu{sub 5}-type DyNi{sub 5} and YNi{sub 4}Si-type DyNi{sub 4}Si lattices.

Structural Design and Analysis of a Rigidizable Space Shuttle Experiment

National Research Council Canada - National Science Library

Holstein

2004-01-01

.... Once in space, the experiment will inflate and rigidize three composite structures and perform a vibration analysis on each by exciting the tubes using piezoelectric patches and collecting data via an accelerometer...

Uniaxial and biaxial tensioning effects on thin membrane materials. [large space structures

Science.gov (United States)

Hinson, W. F.; Goslee, J. W.

1980-01-01

Thin laminated membranes are being considered for various surface applications on future large space structural systems. Some of the thin membranes would be stretched across or between structural members with the requirement that the membrane be maintained within specified limits of smoothness which would be dictated by the particular applications such as antenna reflector requirements. The multiaxial tensile force required to maintain the smoothness in the membrane needs to be determined for use in the structure design. Therefore, several types of thicknesses of thin membrane materials have been subjected to varied levels of uniaxial and biaxial tensile loads. During the biaxial tests, deviations of the material surface smoothness were measured by a noncontacting capacitance probe. Basic materials consisted of composites of vacuum deposited aluminum on Mylar and Kapton ranging in thickness from 0.00025 in (0.000635 cm) to 0.002 in (0.00508 cm). Some of the material was reinforced with Kevlar and Nomex scrim. The uniaxial tests determined the material elongation and tensile forces up to ultimate conditions. Biaxial tests indicated that a relatively smooth material surface could be achieved with tensile force of approximately 1 to 15 Newtons per centimeter, depending upon the material thickness and/or reinforcement.

Types and Dynamics of Gendered Space: A Case of Emirati Female Learners in a Single-Gender Context

Science.gov (United States)

Alzeer, Gergana

2018-01-01

This article is concerned with gendered spaces as they emerge from exploring Emirati female learners' spatiality in a single-gender context. By conducting ethnographic research and utilising Lefebvre's triad of perceived, conceived and lived space for the analysis and categorisation of students' spaces, three types of gendered spaces emerged:…

A new topology for curved space--time which incorporates the causal, differential, and conformal structures

International Nuclear Information System (INIS)

Hawking, S.W.; King, A.R.; McCarthy, P.J.

1976-01-01

A new topology is proposed for strongly causal space--times. Unlike the standard manifold topology (which merely characterizes continuity properties), the new topology determines the causal, differential, and conformal structures of space--time. The topology is more appealing, physical, and manageable than the topology previously proposed by Zeeman for Minkowski space. It thus seems that many calculations involving the above structures may be made purely topological

Classification of proteins: available structural space for molecular modeling.

Science.gov (United States)

Andreeva, Antonina

2012-01-01

The wealth of available protein structural data provides unprecedented opportunity to study and better understand the underlying principles of protein folding and protein structure evolution. A key to achieving this lies in the ability to analyse these data and to organize them in a coherent classification scheme. Over the past years several protein classifications have been developed that aim to group proteins based on their structural relationships. Some of these classification schemes explore the concept of structural neighbourhood (structural continuum), whereas other utilize the notion of protein evolution and thus provide a discrete rather than continuum view of protein structure space. This chapter presents a strategy for classification of proteins with known three-dimensional structure. Steps in the classification process along with basic definitions are introduced. Examples illustrating some fundamental concepts of protein folding and evolution with a special focus on the exceptions to them are presented.

Group structure and group process for effective space station astronaut teams

Science.gov (United States)

Nicholas, J. M.; Kagan, R. S.

1985-01-01

Space Station crews will encounter new problems, many derived from the social interaction of groups working in space for extended durations. Solutions to these problems must focus on the structure of groups and the interaction of individuals. A model of intervention is proposed to address problems of interpersonal relationships and emotional stress, and improve the morale, cohesiveness, and productivity of astronaut teams.

When the going gets tough: behavioural type-dependent space use in the sleepy lizard changes as the season dries.

Science.gov (United States)

Spiegel, Orr; Leu, Stephan T; Sih, Andrew; Godfrey, Stephanie S; Bull, C Michael

2015-11-22

Understanding space use remains a major challenge for animal ecology, with implications for species interactions, disease spread, and conservation. Behavioural type (BT) may shape the space use of individuals within animal populations. Bolder or more aggressive individuals tend to be more exploratory and disperse further. Yet, to date we have limited knowledge on how space use other than dispersal depends on BT. To address this question we studied BT-dependent space-use patterns of sleepy lizards (Tiliqua rugosa) in southern Australia. We combined high-resolution global positioning system (GPS) tracking of 72 free-ranging lizards with repeated behavioural assays, and with a survey of the spatial distributions of their food and refuge resources. Bayesian generalized linear mixed models (GLMM) showed that lizards responded to the spatial distribution of resources at the neighbourhood scale and to the intensity of space use by other conspecifics (showing apparent conspecific avoidance). BT (especially aggressiveness) affected space use by lizards and their response to ecological and social factors, in a seasonally dependent manner. Many of these effects and interactions were stronger later in the season when food became scarce and environmental conditions got tougher. For example, refuge and food availability became more important later in the season and unaggressive lizards were more responsive to these predictors. These findings highlight a commonly overlooked source of heterogeneity in animal space use and improve our mechanistic understanding of processes leading to behaviourally driven disease dynamics and social structure. © 2015 The Author(s).

Guiding exploration in conformational feature space with Lipschitz underestimation for ab-initio protein structure prediction.

Science.gov (United States)

Hao, Xiaohu; Zhang, Guijun; Zhou, Xiaogen

2018-04-01

Computing conformations which are essential to associate structural and functional information with gene sequences, is challenging due to the high dimensionality and rugged energy surface of the protein conformational space. Consequently, the dimension of the protein conformational space should be reduced to a proper level, and an effective exploring algorithm should be proposed. In this paper, a plug-in method for guiding exploration in conformational feature space with Lipschitz underestimation (LUE) for ab-initio protein structure prediction is proposed. The conformational space is converted into ultrafast shape recognition (USR) feature space firstly. Based on the USR feature space, the conformational space can be further converted into Underestimation space according to Lipschitz estimation theory for guiding exploration. As a consequence of the use of underestimation model, the tight lower bound estimate information can be used for exploration guidance, the invalid sampling areas can be eliminated in advance, and the number of energy function evaluations can be reduced. The proposed method provides a novel technique to solve the exploring problem of protein conformational space. LUE is applied to differential evolution (DE) algorithm, and metropolis Monte Carlo(MMC) algorithm which is available in the Rosetta; When LUE is applied to DE and MMC, it will be screened by the underestimation method prior to energy calculation and selection. Further, LUE is compared with DE and MMC by testing on 15 small-to-medium structurally diverse proteins. Test results show that near-native protein structures with higher accuracy can be obtained more rapidly and efficiently with the use of LUE. Copyright © 2018 Elsevier Ltd. All rights reserved.

Structural and evolutionary relationships of "AT-less" type I polyketide synthase ketosynthases.

Science.gov (United States)

Lohman, Jeremy R; Ma, Ming; Osipiuk, Jerzy; Nocek, Boguslaw; Kim, Youngchang; Chang, Changsoo; Cuff, Marianne; Mack, Jamey; Bigelow, Lance; Li, Hui; Endres, Michael; Babnigg, Gyorgy; Joachimiak, Andrzej; Phillips, George N; Shen, Ben

2015-10-13

Acyltransferase (AT)-less type I polyketide synthases (PKSs) break the type I PKS paradigm. They lack the integrated AT domains within their modules and instead use a discrete AT that acts in trans, whereas a type I PKS module minimally contains AT, acyl carrier protein (ACP), and ketosynthase (KS) domains. Structures of canonical type I PKS KS-AT didomains reveal structured linkers that connect the two domains. AT-less type I PKS KSs have remnants of these linkers, which have been hypothesized to be AT docking domains. Natural products produced by AT-less type I PKSs are very complex because of an increased representation of unique modifying domains. AT-less type I PKS KSs possess substrate specificity and fall into phylogenetic clades that correlate with their substrates, whereas canonical type I PKS KSs are monophyletic. We have solved crystal structures of seven AT-less type I PKS KS domains that represent various sequence clusters, revealing insight into the large structural and subtle amino acid residue differences that lead to unique active site topologies and substrate specificities. One set of structures represents a larger group of KS domains from both canonical and AT-less type I PKSs that accept amino acid-containing substrates. One structure has a partial AT-domain, revealing the structural consequences of a type I PKS KS evolving into an AT-less type I PKS KS. These structures highlight the structural diversity within the AT-less type I PKS KS family, and most important, provide a unique opportunity to study the molecular evolution of substrate specificity within the type I PKSs.

Structural and evolutionary relationships of "AT-less" type I polyketide synthase ketosynthases

Energy Technology Data Exchange (ETDEWEB)

Lohman, Jeremy; Ma, Ming; Osipiuk, Jerzy; Nocek, Boguslaw; Kim, Youngchang; Chang, Changsoo; Cuff, Marianne E.; Mack, Jamey; Bigelow, Lance; Li, Hui; Endres, Michael; Babnigg, Gyorgy; Joachimiak, Andrzej; Phillips, George N.; Shen, B G

2015-10-13

Acyltransferase (AT)-less type I polyketide synthases (PKSs) break the type I PKS paradigm. They lack the integrated AT domains within their modules and instead use a discrete AT that acts in trans, whereas a type I PKS module minimally contains AT, acyl carrier protein (ACP), and ketosynthase (KS) domains. Structures of canonical type I PKS KS-AT didomains reveal structured linkers that connect the two domains. AT-less type I PKS KSs have remnants of these linkers, which have been hypothesized to be AT docking domains. Natural products produced by AT-less type I PKSs are very complex because of an increased representation of unique modifying domains. AT-less type I PKS KSs possess substrate specificity and fall into phylogenetic clades that correlate with their substrates, whereas canonical type I PKS KSs are monophyletic. We have solved crystal structures of seven AT-less type I PKS KS domains that represent various sequence clusters, revealing insight into the large structural and subtle amino acid residue differences that lead to unique active site topologies and substrate specificities. One set of structures represents a larger group of KS domains from both canonical and AT-less type I PKSs that accept amino acid-containing substrates. One structure has a partial AT-domain, revealing the structural consequences of a type I PKS KS evolving into an AT-less type I PKS KS. These structures highlight the structural diversity within the AT-less type I PKS KS family, and most important, provide a unique opportunity to study the molecular evolution of substrate specificity within the type I PKSs.

Description of symmetry of magnetic structures by representations of space groups. [Tables, projecton operator methods

Energy Technology Data Exchange (ETDEWEB)

Sikora, W

1974-10-15

A description of magnetic structures based on the use of representations of space groups is given. Representations of the space groups were established for each compound on the basis of experimental data by the method of projection operators. The compounds contained in the list are collected according to crystal systems, alphabetically within each system. The description of each compound consists of the four parts. The first part contain the chemical symbol of the compound, the second its space group. The next part contains the chemical symbol of the magnetic atom and its positions in Wychoff notation with the number of equivalent positions in the crystal unit cell. The main description of a compound magnetic structure is given in the fourth part. It contains: K vector defined in the reciprocal space, the representation according to which a magnetic structure is transformed and the axial vector function S which describes the magnetic structure.

Topology optimization and digital assembly of advanced space-frame structures

DEFF Research Database (Denmark)

Søndergaard, Asbjørn; Amir, Oded; Michael, Knauss

2014-01-01

this paper presents a novel method for integrated design, optimization and fabrication of optimized space-frame structures in an autonomous, digital process. Comparative numerical studies are presented, demonstrating achievable mass reduction by application of the method by comparison to equivalent...... to normative space truss designs and dimensions. As such, a principal digital fabrication and assembly scheme is developed, where an architectural design methodology relative to the described process is established, and the proposed process demonstrated through scaled digital fabrication experiments....

The seesaw space, a vector space to identify and characterize large-scale structures at 1 AU

Science.gov (United States)

Lara, A.; Niembro, T.

2017-12-01

We introduce the seesaw space, an orthonormal space formed by the local and the global fluctuations of any of the four basic solar parameters: velocity, density, magnetic field and temperature at any heliospheric distance. The fluctuations compare the standard deviation of a moving average of three hours against the running average of the parameter in a month (consider as the local fluctuations) and in a year (global fluctuations) We created this new vectorial spaces to identify the arrival of transients to any spacecraft without the need of an observer. We applied our method to the one-minute resolution data of WIND spacecraft from 1996 to 2016. To study the behavior of the seesaw norms in terms of the solar cycle, we computed annual histograms and fixed piecewise functions formed by two log-normal distributions and observed that one of the distributions is due to large-scale structures while the other to the ambient solar wind. The norm values in which the piecewise functions change vary in terms of the solar cycle. We compared the seesaw norms of each of the basic parameters due to the arrival of coronal mass ejections, co-rotating interaction regions and sector boundaries reported in literature. High seesaw norms are due to large-scale structures. We found three critical values of the norms that can be used to determined the arrival of coronal mass ejections. We present as well general comparisons of the norms during the two maxima and the minimum solar cycle periods and the differences of the norms due to large-scale structures depending on each period.

Investigation of DKP equation for spin-zero system in the presence of Goedel-type background space-time

Energy Technology Data Exchange (ETDEWEB)

Hassanabadi, Hassan; Zare, Soroush; Sobhani, Hadi [Shahrood University of Technology, Faculty of Physics, Shahrood (Iran, Islamic Republic of); Chung, Won Sang [Gyeongsang National University, Department of Physics and Research Institute of Natural Science, College of Natural Science, Jinju (Korea, Republic of)

2018-01-15

This paper contains a discussion of a relativistic spin-0 system in the presence of a Goedel-type background space-time. The Duffin-Kemmer-Petiau (DKP) equation in the presence of a Goedel-type background space-time is studied in detail. After a derivation of the final form of this equation in the considered framework, free spin-0 particles have been studied. (orig.)

Quantum theory in real Hilbert space: How the complex Hilbert space structure emerges from Poincaré symmetry

Science.gov (United States)

Moretti, Valter; Oppio, Marco

As earlier conjectured by several authors and much later established by Solèr (relying on partial results by Piron, Maeda-Maeda and other authors), from the lattice theory point of view, Quantum Mechanics may be formulated in real, complex or quaternionic Hilbert spaces only. Stückelberg provided some physical, but not mathematically rigorous, reasons for ruling out the real Hilbert space formulation, assuming that any formulation should encompass a statement of Heisenberg principle. Focusing on this issue from another — in our opinion, deeper — viewpoint, we argue that there is a general fundamental reason why elementary quantum systems are not described in real Hilbert spaces. It is their basic symmetry group. In the first part of the paper, we consider an elementary relativistic system within Wigner’s approach defined as a locally-faithful irreducible strongly-continuous unitary representation of the Poincaré group in a real Hilbert space. We prove that, if the squared-mass operator is non-negative, the system admits a natural, Poincaré invariant and unique up to sign, complex structure which commutes with the whole algebra of observables generated by the representation itself. This complex structure leads to a physically equivalent reformulation of the theory in a complex Hilbert space. Within this complex formulation, differently from what happens in the real one, all selfadjoint operators represent observables in accordance with Solèr’s thesis, and the standard quantum version of Noether theorem may be formulated. In the second part of this work, we focus on the physical hypotheses adopted to define a quantum elementary relativistic system relaxing them on the one hand, and making our model physically more general on the other hand. We use a physically more accurate notion of irreducibility regarding the algebra of observables only, we describe the symmetries in terms of automorphisms of the restricted lattice of elementary propositions of the

The structure of settlement space in a Polynesian chiefdom

International Nuclear Information System (INIS)

Weisler, M.; Kirch, P.V.

1985-01-01

A major settlement pattern study of a late prehistoric archaeological landscape on Molokaii Island, Hawaii, is summarised. The study focusses on the structure of settlement space within a 7.7 sq. km area situated along the south-central coast of Molokaii, and encompassing two traditional land units (ahupua'a), Kawela and Makakupaia Iki. Intensive survey resulted in the discovery of 499 architectural features. These features were recorded using a standardised data-base system (designed for computerised analysis using SPSS) with 37 discrete and continuous variable, including environmental data, architectural attributes, metrical data, and the presence and density of surface cultural materials. Seventy-two structural features (14 percent of the total sample) were excavated; the total excavated area of 442.5 sq. m provides the largest subsurface data base associated with an intensive settlement pattern survey in the Hawaiian Islands. The late prehistoric and largely contemporaneous nature of this sample is indicated by 13 radiocarbon age determinations, ranging from A.D. 1650-1820. The possibilities for directly applying ethnohistoric models in the analysis and interpretation of this settlement pattern are enhanced by the protohistoric age of the archaeological landscape. The structure of settlement space at Kawela and Makakupaia Iki is examined from the perspectives of several paradigms, including environmental, social, economic and semiotic. No single paradigm provides an adequate account of the variation and complexity of the settlement landscape; in consort, however, these varied perspectives contribute to an enhanced understanding of the structure of late prehistoric Hawaiian society

Research on the new type of multi-functional satellite system for space debris detection

Science.gov (United States)

Guo, Linghua; Fu, Qiang; Jiang, Huilin; Xu, Xihe

2017-05-01

With the rapid development of space exploration and utilization, orbital debris increases dramatically, leading to great threat to human space activities and spacecraft security. In this paper, a new type of multi-functional space debris satellite system (MSDS) was put forward, which shared main optical system, and possessed functions of multidimensional information detection, polarized remote sensing and high rate transmission. The MSDS system can meet the requirements of detection and identification for the small orbital debris which is 1000km faraway, as well as the requirements of the data transmission by 50 Mbps to 2.5 Gbps@200-1000 km. At the same time, by the method of satellite orbital maneuver and attitude adjusting, the orbital debris information that is real-time, complex and refined, allweather can be acquired and transmitted by the new system. Such new type of multifunctional satellite system can provide important and effective technology for international orbital debris detection.

Multipactor suppression by micro-structured gold/silver coatings for space applications

Energy Technology Data Exchange (ETDEWEB)

Nistor, Valentin, E-mail: valentin.nistor@uam.es [Departamento de Fisica Aplicada, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); González, Luis A. [Departamento de Fisica Aplicada, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Aguilera, Lydya; Montero, Isabel [Instituto de Ciencia de Materiales de Madrid (CSIC), Cantoblanco, 28049 Madrid (Spain); Galán, Luis [Departamento de Fisica Aplicada, Universidad Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Wochner, Ulrich [Tesat Spacecom GmbH and Co. KG,Gerberstr. 49, D-71522 Backnang (Germany); Raboso, David [European Space Agency (ESA), European Space Research and Technology Centre (ESTEC), 2200 AG Noordwijk (Netherlands)

2014-10-01

Highlights: • Total suppression of the multipactor effect was achieved for a specific configuration of a high RF power K{sub u}-band waveguide. • Secondary emission of electrons was decreased by surfaces of high aspect ratio. • Simple techniques were used in the manufacturing of metallic microscopical rough coatings. • Surface analysis of the treatment was performed. • The RF insertion losses were improved with respect to Alodine, the standard coating for space applications. - Abstract: The secondary electron emission (SEE) from materials used in high power RF devices in space is the main trigger and sustaining mechanism of the resonant avalanche electron discharge known as the multipactor effect. It limits the attainable power of those devices. During recent decades, some scientific research has been focused on material properties for obtaining anti-multipactor coatings of low secondary emission yield (SEY). The European Space Agency (ESA) is leading a technological research on a new approach based on surface roughness that might perform as a kind of blackbody or Faraday cage effect. A multilayer coating structure was adopted for fulfilling the stringent requirements of the space. The surface of a standard silver plating was modified by a two-step treatment. First, a wet chemically etching process created a roughness of high aspect ratio, in the scale of microns. Secondly, the surface was coated with a protective 2 μm overlayer of gold, using magnetron sputtering. This anti-multipactor coating has been tested on several types of K{sub u}-band WR75 waveguide transformers and band-pass filters, with excellent results. The multipactor effect was suppressed for two waveguides, even when applying the maximum available power levels. As for the other final four, the increase of multipactor power level was in the range of 4–6 dB. These results were obtained after more than one year of air exposure. In spite of the strong roughness, the insertion losses were

Multipactor suppression by micro-structured gold/silver coatings for space applications

International Nuclear Information System (INIS)

Nistor, Valentin; González, Luis A.; Aguilera, Lydya; Montero, Isabel; Galán, Luis; Wochner, Ulrich; Raboso, David

2014-01-01

Highlights: • Total suppression of the multipactor effect was achieved for a specific configuration of a high RF power K u -band waveguide. • Secondary emission of electrons was decreased by surfaces of high aspect ratio. • Simple techniques were used in the manufacturing of metallic microscopical rough coatings. • Surface analysis of the treatment was performed. • The RF insertion losses were improved with respect to Alodine, the standard coating for space applications. - Abstract: The secondary electron emission (SEE) from materials used in high power RF devices in space is the main trigger and sustaining mechanism of the resonant avalanche electron discharge known as the multipactor effect. It limits the attainable power of those devices. During recent decades, some scientific research has been focused on material properties for obtaining anti-multipactor coatings of low secondary emission yield (SEY). The European Space Agency (ESA) is leading a technological research on a new approach based on surface roughness that might perform as a kind of blackbody or Faraday cage effect. A multilayer coating structure was adopted for fulfilling the stringent requirements of the space. The surface of a standard silver plating was modified by a two-step treatment. First, a wet chemically etching process created a roughness of high aspect ratio, in the scale of microns. Secondly, the surface was coated with a protective 2 μm overlayer of gold, using magnetron sputtering. This anti-multipactor coating has been tested on several types of K u -band WR75 waveguide transformers and band-pass filters, with excellent results. The multipactor effect was suppressed for two waveguides, even when applying the maximum available power levels. As for the other final four, the increase of multipactor power level was in the range of 4–6 dB. These results were obtained after more than one year of air exposure. In spite of the strong roughness, the insertion losses were

CeSiCò - a new technology for lightweight and cost effective space instruments structures and mirrors

Science.gov (United States)

Devilliers, Christophe; Krödel, Matthias

2017-11-01

Alcatel Alenia Space and ECM have jointly developed a new ceramic material to produce lightweight, stiff, stable and cost effective structures and mirrors for space instrument the CesicÒ. Its intrinsic properties, added to ample manufacturing capabilities allow to manufacture stiff and lightweight cost effective mirrors and structure for space instruments. Different scale 1 flight representative CesicÒ optical structures have been manufactured and successfully tested under very strong dynamic environment and cryogenic condition down to 30K CesicÒ is also envisaged for large and lightweight space telescopes mirrors, a large CesicÒ 1 meter class mirror with an area mass of less than 25 Kg/m2 has been sized again launch loads and WFE performance and manufactured. CesicÒ applicability for large focal plane have been demonstrated through different scale 1 breadboards. Based on these successful results, AlcatelAleniaSpace and ECM are now in position to propose for space this technology with new innovative concepts thanks to the CesicÒ manufacturing capabilities. CesicÒ has therefore been selected for the structure and mirrors parts of a flight instrument payload and the manufacturing of the flight hardware is already underway. An high temperature high gain lightweight antenna breadboard is also under manufacturing for Bepi colombo mission. CesicÒ is therefore a good candidate for future challenging space instruments and is currently proposed for Japan and US space projects.

Some Fixed Point Results for Caristi Type Mappings in Modular Metric Spaces with an Application

Directory of Open Access Journals (Sweden)

Duran Turkoglu

2016-08-01

Full Text Available In this paper we give Caristi type fixed point theorem in complete modular metric spaces. Moreover we give a theorem which can be derived from Caristi type. Also an application for the bounded solution of funcional equations is investigated.

The chaotic region of Lorenz-type system in the parametric space

International Nuclear Information System (INIS)

Liao Haohui; Zhou Tianshou; Tang Yun

2004-01-01

A Lorenz-type system is introduced in this paper. The system contains as special cases the Lorenz system, Chen system and Lue system. The distribution of chaos of the system in the parametric space is numerically investigated. At the same time a set of conditions for possible existence of chaos are given, which guideline the range of searching chaos in the numerical simulation

The Structure-Agency Dialectic in Contested Science Spaces: "Do Earthworms Eat Apples?"

Science.gov (United States)

Kane, Justine M.

2015-01-01

Focusing on a group of African American third graders who attend a high-poverty urban school, I explore the structure-agency dialectic within contested spaces situated in a dialogically oriented science classroom. Contested spaces entail the moments in which the students challenge each other's and their teacher's science ideas and, in the process,…

Exact self-consistent solutions to the interacting spinor and scalar field equations in Bianchi type-I space-time

International Nuclear Information System (INIS)

Alvarado, R.; Rybakov, Yu.P.; Shikin, G.N.; Saha, B.

1995-01-01

Self-consistent solutions to the system of spinor and scalar field equations in General Relativity are studied for the case of Bianchi type-I space-time. The absence of initial singularity should be emphasized for some types of solutions and also the isotropic mode of space-time expansion in some special cases. 3 refs

Fibre structure of decametric type II radio bursts as a manifestation of emission propagation effects in a disturbed near-solar plasma

OpenAIRE

A. N. Afanasiev

2009-01-01

This paper addresses the fine structure of solar decametric type II radio bursts in the form of drifting narrowband fibres on the dynamic spectrum. Observations show that this structure appears in those events where there is a coronal mass ejection (CME) traveling in the near-solar space ahead of the shock wave responsible for the radio burst. The diversity in observed morphology of fibres and values of their parameters implies that the fibres may be caused by different formation mechanisms. ...

Scale Space Methods for Analysis of Type 2 Diabetes Patients' Blood Glucose Values

Directory of Open Access Journals (Sweden)

Stein Olav Skrøvseth

2011-01-01

Full Text Available We describe how scale space methods can be used for quantitative analysis of blood glucose concentrations from type 2 diabetes patients. Blood glucose values were recorded voluntarily by the patients over one full year as part of a self-management process, where the time and frequency of the recordings are decided by the patients. This makes a unique dataset in its extent, though with a large variation in reliability of the recordings. Scale space and frequency space techniques are suited to reveal important features of unevenly sampled data, and useful for identifying medically relevant features for use both by patients as part of their self-management process, and provide useful information for physicians.

An Owen-type value for games with two-level communication structures

NARCIS (Netherlands)

van den Brink, René; Khmelnitskaya, Anna Borisovna; van der Laan, Gerard

We introduce an Owen-type value for games with two-level communication structure, which is a structure where the players are partitioned into a coalition structure such that there exists restricted communication between as well as within the a priori unions of the coalition structure. Both types of

Modal-space reference-model-tracking fuzzy control of earthquake excited structures

Science.gov (United States)

Park, Kwan-Soon; Ok, Seung-Yong

2015-01-01

This paper describes an adaptive modal-space reference-model-tracking fuzzy control technique for the vibration control of earthquake-excited structures. In the proposed approach, the fuzzy logic is introduced to update optimal control force so that the controlled structural response can track the desired response of a reference model. For easy and practical implementation, the reference model is constructed by assigning the target damping ratios to the first few dominant modes in modal space. The numerical simulation results demonstrate that the proposed approach successfully achieves not only the adaptive fault-tolerant control system against partial actuator failures but also the robust performance against the variations of the uncertain system properties by redistributing the feedback control forces to the available actuators.

Role of Structural Asymmetry in Controlling Drop Spacing in Microfluidic Ladder Networks

Science.gov (United States)

Wang, William; Maddala, Jeevan; Vanapalli, Siva; Rengasamy, Raghunathan

2012-02-01

Manipulation of drop spacing is crucial to many processes in microfluidic devices including drop coalescence, detection and storage. Microfluidic ladder networks ---where two droplet-carrying parallel channels are connected by narrow bypass channels through which the motion of drops is forbidden---have been proposed as a means to control relative separation between pairs of drops. Prior studies in microfluidic ladder networks with vertical bypasses, which possess fore-aft structural symmetry, have revealed that pairs of drops can only undergo reduction in drop spacing at the ladder exit. We investigate the dynamics of drops in microfluidic ladder networks with both vertical and slanted bypasses. Our analytical results indicate that unlike symmetric ladder networks, structural asymmetry introduced by a single slanted bypass can be used to modulate the relative spacing between drops, enabling them to contract, synchronize, expand or even flip at the ladder exit. Our experiments confirm all the behaviors predicted by theory. Numerical analysis further shows that ladders containing several identical bypasses can only linearly transform the input drop spacing. Finally, we find that ladders with specific combinations of vertical and slanted bypasses can generate non-linear transformation of input drop spacing, despite the absence of drop decision-making events at the bypass junctions.

Time-space structure of nuclear safety

International Nuclear Information System (INIS)

Miya, Kenzo

2003-01-01

New idea to analyze the structure of nuclear safety and to investigate functioning property of hierarchical principle is applied to nuclear safety in this paper. The nuclear safety is expressed by three principles such as 1) the action and subject are partitioned and classified by time and space, 2) introduction of hierarchy with three strata to the closed object and hierarchy with many strata to the open object and 3) application of 'element, relation and abstraction' to the engineering system as a framework of intellectual activity. For example, prevention of core melt is the closed object and it is obtained by acting hierarchies with three strata (operation stop, cooling and closing radiation) as the safety functions. Prevention of increase of accident is open object, so that, space hierarchy with many strata of prevention is used for the safety security of reactor. The safety security method of reactor consists of three processes, that is 1) the basic process to make clear the continuous operating time on the basis of regular inspection, 2) the action process of operating ECCS to prevent core damage accident, when a large leakage happens and 3) many strata prevention process of stopping a leak in the environment. (S.Y.)

Tracking Solar Type II Bursts with Space Based Radio Interferometers

Science.gov (United States)

Hegedus, Alexander M.; Kasper, Justin C.; Manchester, Ward B.

2018-06-01

The Earth’s Ionosphere limits radio measurements on its surface, blocking out any radiation below 10 MHz. Valuable insight into many astrophysical processes could be gained by having a radio interferometer in space to image the low frequency window for the first time. One application is observing type II bursts tracking solar energetic particle acceleration in Coronal Mass Ejections (CMEs). In this work we create a simulated data processing pipeline for several space based radio interferometer (SBRI) concepts and evaluate their performance in the task of localizing these type II bursts.Traditional radio astronomy software is hard coded to assume an Earth based array. To circumvent this, we manually calculate the antenna separations and insert them along with the simulated visibilities into a CASA MS file for analysis. To create the realest possible virtual input data, we take a 2-temperature MHD simulation of a CME event, superimpose realistic radio emission models from the CME-driven shock front, and propagate the signal through simulated SBRIs. We consider both probabilistic emission models derived from plasma parameters correlated with type II bursts, and analytical emission models using plasma emission wave interaction theory.One proposed SBRI is the pathfinder mission SunRISE, a 6 CubeSat interferometer to circle the Earth in a GEO graveyard orbit. We test simulated trajectories of SunRISE and image what the array recovers, comparing it to the virtual input. An interferometer on the lunar surface would be a stable alternative that avoids noise sources that affect orbiting arrays, namely the phase noise from positional uncertainty and atmospheric 10s-100s kHz noise. Using Digital Elevation Models from laser altimeter data, we test different sets of locations on the lunar surface to find near optimal configurations for tracking type II bursts far from the sun. Custom software is used to model the response of different array configurations over the lunar year

Stochastic Fatigue Analysis of Jacket Type Offshore Structures

DEFF Research Database (Denmark)

Sigurdsson, Gudfinnur

In this paper, a stochastic reliability assessment for jacket type offshore structures subjected to wave loads in deep water environments is outlined. In the reliability assessment, structural and loading uncertainties are taken into account by means of some stochastic variables. To estimate stat...... statistical measures of structural stress variations the modal spectral analysis method is applied....

Perception of Peripersonal and Interpersonal Space in Patients with Restrictive-type Anorexia.

Science.gov (United States)

Nandrino, Jean-Louis; Ducro, Claire; Iachini, Tina; Coello, Yann

2017-05-01

This study examines whether the perception of peripersonal action-space and interpersonal social-space is modified in patients with restrictive-type anorexia in two experimental conditions using videos. First, participants stopped the video of an approaching stimulus when they felt the distance to be comfortable for interacting with it (first-person perspective). Second, participants stopped the video when an observed individual approaching a stimulus, or being approached by it, was at a comfortable distance (third-person perspective). In the first-person perspective, the results showed an estimation of peripersonal space that did not differ from controls when an object was approaching and an increase in interpersonal space compared with controls when a male or female individual was approaching. In the third-person perspective, both individual-object and individual-individual distances were larger in anorexic patients. These results indicate a specific deficit in adjusting interpersonal distances in both the first-person and third-person perspectives. Copyright © 2017 John Wiley & Sons, Ltd and Eating Disorders Association. Copyright © 2017 John Wiley & Sons, Ltd and Eating Disorders Association.

On the Fonte structure between a pair of Banach spaces

International Nuclear Information System (INIS)

Sharma, C.S.

1990-01-01

The main purpose of the present note is to establish the essential equivalence of the adjoint of a semilinear map defined through the Fonte structure between a pair of Banach spaces and the adjoint of the same map defined by Pian and the present author

Unified Symmetry of Nonholonomic System of Non-Chetaev's Type in Event Space

International Nuclear Information System (INIS)

Hou Qibao; Li Yuancheng; Wang Jing; Xia Lili

2007-01-01

The unified symmetry of a nonholonomic system of non-Chetaev's type in event space under infinitesimal transformations of group is studied. Firstly, the differential equations of motion of the system are given. Secondly, the definition and the criterion of the unified symmetry for the system are obtained. Thirdly, a new conserved quantity, besides the Noether conserved quantity and the Hojman conserved quantity, is deduced from the unified symmetry of a nonholonomic system of non-Chetaev's type. Finally, an example is given to illustrate the application of the result.

Fluid bilayer structure determination: Joint refinement in composition space using X-ray and neutron diffraction data

Energy Technology Data Exchange (ETDEWEB)

White, S.H. [Univ. of California, Irvine, CA (United States); Wiener, M.C. [Univ. of California, San Francisco, CA (United States)

1994-12-31

Experimentally-determined structural models of fluid lipid bilayers are essential for verifying molecular dynamics simulations of bilayers and for understanding the structural consequences of peptide interactions. The extreme thermal motion of bilayers precludes the possibility of atomic-level structural models. Defining {open_quote}the structure{close_quote} of a bilayer as the time-averaged transbilayer distribution of the water and the principal lipid structural groups such as the carbonyls and double-bonds (quasimolecular fragments), one can represent the bilayer structure as a sum of Gaussian functions referred to collectively as the quasimolecular structure. One method of determining the structure is by neutron diffraction combined with exhaustive specific deuteration. This method is impractical because of the expense of the chemical syntheses and the limited amount of neutron beam time currently available. We have therefore developed the composition space refinement method for combining X-ray and minimal neutron diffraction data to arrive at remarkably detailed and accurate structures of fluid bilayers. The composition space representation of the bilayer describes the probability of occupancy per unit length across the width of the bilayer of each quasimolecular component and permits the joint refinement of X-ray and neutron lamellar diffraction data by means of a single quasimolecular structure that is fitted simultaneously to both data sets. Scaling of each component by the appropriate neutron or X-ray scattering length maps the composition-space profile to the appropriate scattering length space for comparison to experimental data. The difficulty with the method is that fluid bilayer structures are generally only marginally determined by the experimental data. This means that the space of possible solutions must be extensively explored in conjunction with a thorough analysis of errors.

Fluid bilayer structure determination: Joint refinement in composition space using X-ray and neutron diffraction data

International Nuclear Information System (INIS)

White, S.H.; Wiener, M.C.

1994-01-01

Experimentally-determined structural models of fluid lipid bilayers are essential for verifying molecular dynamics simulations of bilayers and for understanding the structural consequences of peptide interactions. The extreme thermal motion of bilayers precludes the possibility of atomic-level structural models. Defining open-quote the structure close-quote of a bilayer as the time-averaged transbilayer distribution of the water and the principal lipid structural groups such as the carbonyls and double-bonds (quasimolecular fragments), one can represent the bilayer structure as a sum of Gaussian functions referred to collectively as the quasimolecular structure. One method of determining the structure is by neutron diffraction combined with exhaustive specific deuteration. This method is impractical because of the expense of the chemical syntheses and the limited amount of neutron beam time currently available. We have therefore developed the composition space refinement method for combining X-ray and minimal neutron diffraction data to arrive at remarkably detailed and accurate structures of fluid bilayers. The composition space representation of the bilayer describes the probability of occupancy per unit length across the width of the bilayer of each quasimolecular component and permits the joint refinement of X-ray and neutron lamellar diffraction data by means of a single quasimolecular structure that is fitted simultaneously to both data sets. Scaling of each component by the appropriate neutron or X-ray scattering length maps the composition-space profile to the appropriate scattering length space for comparison to experimental data. The difficulty with the method is that fluid bilayer structures are generally only marginally determined by the experimental data. This means that the space of possible solutions must be extensively explored in conjunction with a thorough analysis of errors

Ducks in space: from nonlinear absolute instability to noise-sustained structures in a pattern-forming system

Science.gov (United States)

Avitabile, D.; Desroches, M.; Knobloch, E.; Krupa, M.

2017-11-01

A subcritical pattern-forming system with nonlinear advection in a bounded domain is recast as a slow-fast system in space and studied using a combination of geometric singular perturbation theory and numerical continuation. Two types of solutions describing the possible location of stationary fronts are identified, whose origin is traced to the onset of convective and absolute instability when the system is unbounded. The former are present only for non-zero upstream boundary conditions and provide a quantitative understanding of noise-sustained structures in systems of this type. The latter correspond to the onset of a global mode and are present even with zero upstream boundary conditions. The role of canard trajectories in the nonlinear transition between these states is clarified and the stability properties of the resulting spatial structures are determined. Front location in the convective regime is highly sensitive to the upstream boundary condition, and its dependence on this boundary condition is studied using a combination of numerical continuation and Monte Carlo simulations of the partial differential equation. Statistical properties of the system subjected to random or stochastic boundary conditions at the inlet are interpreted using the deterministic slow-fast spatial dynamical system.

Interactive Spaces: Towards Collaborative structuring and Ubiquitous Presentation in Domestic Environment

DEFF Research Database (Denmark)

Petersen, Marianne Graves; Grønbæk, Kaj

2004-01-01

collaborative structuring and ubiquitous presentation of materials in private homes. With DoHM we propose establishing new relationship between digital and physical hyperspaces, folding hyperspaces into the physical space of the household. Thus we strive to combine the qualities of physical domestic materials...... and spaces with the flexibility and dynamics of digital hyperspaces. We propose a variety of new ubiquitous home appliances called MediaWall, MediaTable, MediaTray and MediaPort, which address these issues....

Interactive Spaces: Towards Collaborative Structuring and Ubiquitous Presentation in Domestic Environments

DEFF Research Database (Denmark)

Petersen, Marianne Graves; Grønbæk, Kaj

2004-01-01

collaborative structuring and ubiquitous presentation of materials in private homes. With DoHM we propose establishing new relationship between digital and physical hyperspaces, folding hyperspaces into the physical space of the household. Thus we strive to combine the qualities of physical domestic materials...... and spaces with the flexibility and dynamics of digital hyperspaces. We propose a variety of new ubiquitous home appliances called MediaWall, MediaTable, MediaTray and MediaPort, which address these issues....

Recent developments of advanced structures for space optics at Astrium, Germany

Science.gov (United States)

Stute, Thomas; Wulz, Georg; Scheulen, Dietmar

2003-12-01

The mechanical division of EADS Astrium GmbH, Friedrichshafen Germany, the former Dornier Satellitensystem GmbH is currently engaged with the development, manufacturing and testing of three different advanced dimensionally stable composite and ceramic material structures for satellite borne optics: -CFRP Camera Structure -Planck Telescope Reflectors -NIRSpec Optical Bench Breadboard for James Web Space Telescope The paper gives an overview over the requirements and the main structural features how these requirements are met. Special production aspects and available test results are reported.

The structure and properties of color spaces and the representation of color images

CERN Document Server

Dubois, Eric

2009-01-01

This lecture describes the author's approach to the representation of color spaces and their use for color image processing. The lecture starts with a precise formulation of the space of physical stimuli (light). The model includes both continuous spectra and monochromatic spectra in the form of Dirac deltas. The spectral densities are considered to be functions of a continuous wavelength variable. This leads into the formulation of color space as a three-dimensional vector space, with all the associated structure. The approach is to start with the axioms of color matching for normal human vie

LOSS OF SPACE ACCORDING TO THE TIME AND THE TYPE OF THE PREMATURE EXTRACTED DECIDUOUS TEETH

Directory of Open Access Journals (Sweden)

Radosveta S. Andreeva

2016-06-01

Full Text Available There is a difference of space loss depending on the time of premature extraction and the type of the prematurely extracted teeth. The aim of the study is to determine the space loss according to the time and the type of the extracted teeth. Material and methods: We studied 90 children 6 to 9 years old with premature loss of one or more primary teeth divided into three groups according to the severity of the orthodontic deformation. We used two biometric methods – the Moyers method and measured the mesial and distal movement of the adjustment teeth by drawing perpendicular lines towards the middle line. Results: The average amount of space lost is 0,033 mm for the first group, 2,2 for the second and 3,16 for the third group. The lack of space when the first primary molars are extracted is 0,37 mm in the upper jaw and is due to medicalization of the second primary molar. In the lower jaw the loss of space is – 1,12mm. The lack of space when the second primary molars are prematurely extracted is 1,2 for the upper and 1,45 for the lower jaw. Conclusion: The time is a significant factor for the loss of space. The reduction of space increases when the premature extraction is done before more than two months and when second primary molars are extracted.

Cosmological special relativity the large scale structure of space, time and velocity

CERN Document Server

Carmeli, Moshe

1997-01-01

This book deals with special relativity theory and its application to cosmology. It presents Einstein's theory of space and time in detail, and describes the large scale structure of space, time and velocity as a new cosmological special relativity. A cosmological Lorentz-like transformation, which relates events at different cosmic times, is derived and applied. A new law of addition of cosmic times is obtained, and the inflation of the space at the early universe is derived, both from the cosmological transformation. The book will be of interest to cosmologists, astrophysicists, theoretical

Cosmological special relativity the large scale structure of space, time and velocity

CERN Document Server

Carmeli, Moshe

2002-01-01

This book presents Einstein's theory of space and time in detail, and describes the large-scale structure of space, time and velocity as a new cosmological special relativity. A cosmological Lorentz-like transformation, which relates events at different cosmic times, is derived and applied. A new law of addition of cosmic times is obtained, and the inflation of the space at the early universe is derived, both from the cosmological transformation. The relationship between cosmic velocity, acceleration and distances is given. In the appendices gravitation is added in the form of a cosmological g

Invariant description of solutions of hydrodynamic-type systems in hodograph space: hydrodynamic surfaces

International Nuclear Information System (INIS)

Ferapontov, E.V.

2002-01-01

Hydrodynamic surfaces are solutions of hydrodynamic-type systems viewed as non-parametrized submanifolds of the hodograph space. We propose an invariant differential-geometric characterization of hydrodynamic surfaces by expressing the curvature form of the characteristic web in terms of the reciprocal invariants. (author)

Subaortic (Type 6 Muscular Band—Innocent Bystander or Pathologic Structure?

Directory of Open Access Journals (Sweden)

J Ker

2010-08-01

Full Text Available Intraventricular tendons are structures that was identified more than a hundred years ago. It has been suggested that they represent intracavitary radiations of the bundle of His and that they may be an isolated finding or be associated with structural cardiac abnormalities. Loukas et al divided these structures into five categories and recently a sixth type have been added. Various physiological disturbances have been observed due to the sixth type of tendon, such as ST segment elevation and right bundle branch block. It has been noted that this peculiar structure appears too thick to be called a tendon, thus the term band. This retrospective analysis analyzed the incidence of the thick, subaortic (type 6 muscular band in a cardiovascular clinic.

Common Fixed Points of Generalized Rational Type Cocyclic Mappings in Multiplicative Metric Spaces

Directory of Open Access Journals (Sweden)

Mujahid Abbas

2015-01-01

Full Text Available The aim of this paper is to present fixed point result of mappings satisfying a generalized rational contractive condition in the setup of multiplicative metric spaces. As an application, we obtain a common fixed point of a pair of weakly compatible mappings. Some common fixed point results of pair of rational contractive types mappings involved in cocyclic representation of a nonempty subset of a multiplicative metric space are also obtained. Some examples are presented to support the results proved herein. Our results generalize and extend various results in the existing literature.

Scalar Green's functions in an Euclidean space with a conical-type line singularity

International Nuclear Information System (INIS)

Guimaraes, M.E.X.; Linet, B.

1994-01-01

In an Euclidean space with a conical-type line singularity, we determine the Green's function for a charged massive scalar field interacting with a magnetic flux running through the line singularity. We give an integral expression of the Green's function and a local form in the neighbourhood of the point source, where it is the sum of the usual Green's function in Euclidean space and a regular term. As an application, we derive the vacuum energy-momentum tensor in the massless case for an arbitrary magnetic flux. (orig.)

Integrated Modeling for the James Webb Space Telescope (JWST) Project: Structural Analysis Activities

Science.gov (United States)

Johnston, John; Mosier, Mark; Howard, Joe; Hyde, Tupper; Parrish, Keith; Ha, Kong; Liu, Frank; McGinnis, Mark

2004-01-01

This paper presents viewgraphs about structural analysis activities and integrated modeling for the James Webb Space Telescope (JWST). The topics include: 1) JWST Overview; 2) Observatory Structural Models; 3) Integrated Performance Analysis; and 4) Future Work and Challenges.

Structural and evolutionary relationships of “AT-less” type I polyketide synthase ketosynthases

Science.gov (United States)

Lohman, Jeremy R.; Ma, Ming; Osipiuk, Jerzy; Nocek, Boguslaw; Kim, Youngchang; Chang, Changsoo; Cuff, Marianne; Mack, Jamey; Bigelow, Lance; Li, Hui; Endres, Michael; Babnigg, Gyorgy; Joachimiak, Andrzej; Phillips, George N.; Shen, Ben

2015-01-01

Acyltransferase (AT)-less type I polyketide synthases (PKSs) break the type I PKS paradigm. They lack the integrated AT domains within their modules and instead use a discrete AT that acts in trans, whereas a type I PKS module minimally contains AT, acyl carrier protein (ACP), and ketosynthase (KS) domains. Structures of canonical type I PKS KS-AT didomains reveal structured linkers that connect the two domains. AT-less type I PKS KSs have remnants of these linkers, which have been hypothesized to be AT docking domains. Natural products produced by AT-less type I PKSs are very complex because of an increased representation of unique modifying domains. AT-less type I PKS KSs possess substrate specificity and fall into phylogenetic clades that correlate with their substrates, whereas canonical type I PKS KSs are monophyletic. We have solved crystal structures of seven AT-less type I PKS KS domains that represent various sequence clusters, revealing insight into the large structural and subtle amino acid residue differences that lead to unique active site topologies and substrate specificities. One set of structures represents a larger group of KS domains from both canonical and AT-less type I PKSs that accept amino acid-containing substrates. One structure has a partial AT-domain, revealing the structural consequences of a type I PKS KS evolving into an AT-less type I PKS KS. These structures highlight the structural diversity within the AT-less type I PKS KS family, and most important, provide a unique opportunity to study the molecular evolution of substrate specificity within the type I PKSs. PMID:26420866

Local symplectic operators and structures related to them

International Nuclear Information System (INIS)

Dorfman, I.Y.; Mokhov, O.I.

1991-01-01

Matrices with entries being differential operators, that endow the phase space of an evolution system with a (pre)symplectic structure are considered. Special types of such structures are explicitly described. Links with integrability, geometry of loop spaces, and Baecklund transformations are traces

Crystal structure of the second fibronectin type III (FN3) domain from human collagen α1 type XX.

Science.gov (United States)

Zhao, Jingfeng; Ren, Jixia; Wang, Nan; Cheng, Zhong; Yang, Runmei; Lin, Gen; Guo, Yi; Cai, Dayong; Xie, Yong; Zhao, Xiaohong

2017-12-01

Collagen α1 type XX, which contains fibronectin type III (FN3) repeats involving six FN3 domains (referred to as the FN#1-FN#6 domains), is an unusual member of the fibril-associated collagens with interrupted triple helices (FACIT) subfamily of collagens. The results of standard protein BLAST suggest that the FN3 repeats might contribute to collagen α1 type XX acting as a cytokine receptor. To date, solution NMR structures of the FN#3, FN#4 and FN#6 domains have been determined. To obtain further structural evidence to understand the relationship between the structure and function of the FN3 repeats from collagen α1 type XX, the crystal structure of the FN#2 domain from human collagen α1 type XX (residues Pro386-Pro466; referred to as FN2-HCXX) was solved at 2.5 Å resolution. The crystal structure of FN2-HCXX shows an immunoglobulin-like fold containing a β-sandwich structure, which is formed by a three-stranded β-sheet (β1, β2 and β5) packed onto a four-stranded β-sheet (β3, β4, β6 and β7). Two consensus domains, tencon and fibcon, are structural analogues of FN2-HCXX. Fn8, an FN3 domain from human oncofoetal fibronectin, is the closest structural analogue of FN2-HCXX derived from a naturally occurring sequence. Based solely on the structural similarity of FN2-HCXX to other FN3 domains, the detailed functions of FN2-HCXX and the FN3 repeats in collagen α1 type XX cannot be identified.

Pre-Big Bang, space-time structure, asymptotic Universe

Directory of Open Access Journals (Sweden)

Gonzalez-Mestres Luis

2014-04-01

Full Text Available Planck and other recent data in Cosmology and Particle Physics can open the way to controversial analyses concerning the early Universe and its possible ultimate origin. Alternatives to standard cosmology include pre-Big Bang approaches, new space-time geometries and new ultimate constituents of matter. Basic issues related to a possible new cosmology along these lines clearly deserve further exploration. The Planck collaboration reports an age of the Universe t close to 13.8 Gyr and a present ratio H between relative speeds and distances at cosmic scale around 67.3 km/s/Mpc. The product of these two measured quantities is then slightly below 1 (about 0.95, while it can be exactly 1 in the absence of matter and cosmological constant in patterns based on the spinorial space-time we have considered in previous papers. In this description of space-time we first suggested in 1996-97, the cosmic time t is given by the modulus of a SU(2 spinor and the Lundmark-Lemaître-Hubble (LLH expansion law turns out to be of purely geometric origin previous to any introduction of standard matter and relativity. Such a fundamental geometry, inspired by the role of half-integer spin in Particle Physics, may reflect an equilibrium between the dynamics of the ultimate constituents of matter and the deep structure of space and time. Taking into account the observed cosmic acceleration, the present situation suggests that the value of 1 can be a natural asymptotic limit for the product H t in the long-term evolution of our Universe up to possible small corrections. In the presence of a spinorial space-time geometry, no ad hoc combination of dark matter and dark energy would in any case be needed to get an acceptable value of H and an evolution of the Universe compatible with observation. The use of a spinorial space-time naturally leads to unconventional properties for the space curvature term in Friedmann-like equations. It therefore suggests a major modification of

Impact of inhomogeneity on SH-type wave propagation in an initially stressed composite structure

Science.gov (United States)

Saha, S.; Chattopadhyay, A.; Singh, A. K.

2018-02-01

The present analysis has been made on the influence of distinct form of inhomogeneity in a composite structure comprised of double superficial layers lying over a half-space, on the phase velocity of SH-type wave propagating through it. Propagation of SH-type wave in the said structure has been examined in four distinct cases of inhomogeneity viz. when inhomogeneity in double superficial layer is due to exponential variation in density only (Case I); when inhomogeneity in double superficial layers is due to exponential variation in rigidity only (Case II); when inhomogeneity in double superficial layer is due to exponential variation in rigidity, density and initial stress (Case III) and when inhomogeneity in double superficial layer is due to linear variation in rigidity, density and initial stress (Case IV). Closed-form expression of dispersion relation has been accomplished for all four aforementioned cases through extensive application of Debye asymptotic analysis. Deduced dispersion relations for all the cases are found in well-agreement to the classical Love-wave equation. Numerical computation has been carried out to graphically demonstrate the effect of inhomogeneity parameters, initial stress parameters as well as width ratio associated with double superficial layers in the composite structure for each of the four aforesaid cases on dispersion curve. Meticulous examination of distinct cases of inhomogeneity and initial stress in context of considered problem has been carried out with detailed analysis in a comparative approach.

Structural health monitoring using DOG multi-scale space: an approach for analyzing damage characteristics

Science.gov (United States)

Guo, Tian; Xu, Zili

2018-03-01

Measurement noise is inevitable in practice; thus, it is difficult to identify defects, cracks or damage in a structure while suppressing noise simultaneously. In this work, a novel method is introduced to detect multiple damage in noisy environments. Based on multi-scale space analysis for discrete signals, a method for extracting damage characteristics from the measured displacement mode shape is illustrated. Moreover, the proposed method incorporates a data fusion algorithm to further eliminate measurement noise-based interference. The effectiveness of the method is verified by numerical and experimental methods applied to different structural types. The results demonstrate that there are two advantages to the proposed method. First, damage features are extracted by the difference of the multi-scale representation; this step is taken such that the interference of noise amplification can be avoided. Second, a data fusion technique applied to the proposed method provides a global decision, which retains the damage features while maximally eliminating the uncertainty. Monte Carlo simulations are utilized to validate that the proposed method has a higher accuracy in damage detection.

Hierarchical phase space structure of dark matter haloes: Tidal debris, caustics, and dark matter annihilation

International Nuclear Information System (INIS)

Afshordi, Niayesh; Mohayaee, Roya; Bertschinger, Edmund

2009-01-01

Most of the mass content of dark matter haloes is expected to be in the form of tidal debris. The density of debris is not constant, but rather can grow due to formation of caustics at the apocenters and pericenters of the orbit, or decay as a result of phase mixing. In the phase space, the debris assemble in a hierarchy that is truncated by the primordial temperature of dark matter. Understanding this phase structure can be of significant importance for the interpretation of many astrophysical observations and, in particular, dark matter detection experiments. With this purpose in mind, we develop a general theoretical framework to describe the hierarchical structure of the phase space of cold dark matter haloes. We do not make any assumption of spherical symmetry and/or smooth and continuous accretion. Instead, working with correlation functions in the action-angle space, we can fully account for the hierarchical structure (predicting a two-point correlation function ∝ΔJ -1.6 in the action space), as well as the primordial discreteness of the phase space. As an application, we estimate the boost to the dark matter annihilation signal due to the structure of the phase space within virial radius: the boost due to the hierarchical tidal debris is of order unity, whereas the primordial discreteness of the phase structure can boost the total annihilation signal by up to an order of magnitude. The latter is dominated by the regions beyond 20% of the virial radius, and is largest for the recently formed haloes with the least degree of phase mixing. Nevertheless, as we argue in a companion paper, the boost due to small gravitationally-bound substructure can dominate this effect at low redshifts.

Hierarchical phase space structure of dark matter haloes: Tidal debris, caustics, and dark matter annihilation

Science.gov (United States)

Afshordi, Niayesh; Mohayaee, Roya; Bertschinger, Edmund

2009-04-01

Most of the mass content of dark matter haloes is expected to be in the form of tidal debris. The density of debris is not constant, but rather can grow due to formation of caustics at the apocenters and pericenters of the orbit, or decay as a result of phase mixing. In the phase space, the debris assemble in a hierarchy that is truncated by the primordial temperature of dark matter. Understanding this phase structure can be of significant importance for the interpretation of many astrophysical observations and, in particular, dark matter detection experiments. With this purpose in mind, we develop a general theoretical framework to describe the hierarchical structure of the phase space of cold dark matter haloes. We do not make any assumption of spherical symmetry and/or smooth and continuous accretion. Instead, working with correlation functions in the action-angle space, we can fully account for the hierarchical structure (predicting a two-point correlation function ∝ΔJ-1.6 in the action space), as well as the primordial discreteness of the phase space. As an application, we estimate the boost to the dark matter annihilation signal due to the structure of the phase space within virial radius: the boost due to the hierarchical tidal debris is of order unity, whereas the primordial discreteness of the phase structure can boost the total annihilation signal by up to an order of magnitude. The latter is dominated by the regions beyond 20% of the virial radius, and is largest for the recently formed haloes with the least degree of phase mixing. Nevertheless, as we argue in a companion paper, the boost due to small gravitationally-bound substructure can dominate this effect at low redshifts.

Spectral investigation of a complex space charge structure in plasma

International Nuclear Information System (INIS)

Gurlui, S.; Dimitriu, D. G.; Ionita, C.; Schrittwieser, R. W.

2009-01-01

Complex space charge structures bordered by electrical double layers were spectrally investigated in argon plasma in the domain 400-1000 nm, identifying the lines corresponding to the transitions from different excited states of argon. The electron excitation temperature in the argon atoms was estimated from the spectral lines intensity ratio. (authors)

Stellar Photometric Structures of the Host Galaxies of Nearby Type 1 Active Galactic Nuclei

Energy Technology Data Exchange (ETDEWEB)

Kim, Minjin [Korea Astronomy and Space Science Institute, Daejeon 305-348 (Korea, Republic of); Ho, Luis C. [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Peng, Chien Y. [Giant Magellan Telescope Corporation, 251 S. Lake Ave., Suite 300, Pasadena, CA 91101 (United States); Barth, Aaron J. [Department of Physics and Astronomy, University of California at Irvine, 4129 Frederick Reines Hall, Irvine, CA 92697-4575 (United States); Im, Myungshin, E-mail: mkim@kasi.re.kr, E-mail: lho.pku@gmail.com, E-mail: peng@gmto.org, E-mail: barth@uci.edu, E-mail: mim@astro.snu.ac.kr [Department of Physics and Astronomy, Frontier Physics Research Division (FPRD), Seoul National University, Seoul (Korea, Republic of)

2017-10-01

We present detailed image analysis of rest-frame optical images of 235 low-redshift ( z ≲ 0.35) Type 1 active galactic nuclei (AGNs) observed with the Hubble Space Telescope . The high-resolution images enable us to perform rigorous two-dimensional image modeling to decouple the luminous central point source from the host galaxy, which, when warranted, is further decomposed into its principal structural components (bulge, bar, and disk). In many cases, care must be taken to account for structural complexities such as spiral arms, tidal features, and overlapping or interacting companion galaxies. We employ Fourier modes to characterize the degree of asymmetry of the light distribution of the stars as a quantitative measure of morphological distortion due to interactions or mergers. We examine the dependence of the physical parameters of the host galaxies on the properties of the AGNs, namely, radio-loudness and the width of the broad emission lines. In accordance with previous studies, narrow-line (H β FWHM ≤ 2000 km s{sup −1}) Type 1 AGNs, in contrast to their broad-line (H β FWHM > 2000 km s{sup −1}) counterparts, are preferentially hosted in later-type, lower-luminosity galaxies, which have a higher incidence of pseudo-bulges, are more frequently barred, and are less morphologically disturbed. This suggests that narrow-line Type 1 AGNs experienced a more quiescent evolutionary history driven primarily by internal secular evolution instead of external dynamical perturbations. The fraction of AGN hosts showing merger signatures is larger for more luminous sources. Radio-loud AGNs generally preferentially live in earlier-type (bulge-dominated), more massive hosts, although a minority of them appear to contain a significant disk component. We do not find convincing evidence for enhanced merger signatures in the radio-loud population.

Space Launch System, Core Stage, Structural Test Design and Implementation

Science.gov (United States)

Shaughnessy, Ray

2017-01-01

As part of the National Aeronautics and Space Administration's (NASA) Space Launch System (SLS) Program, engineers at NASA's Marshall Space Flight Center (MSFC) in Huntsville, Alabama are working to design, develop and implement the SLS Core Stage structural testing. The SLS will have the capability to return humans to the Moon and beyond and its first launch is scheduled for December of 2017. The SLS Core Stage consist of five major elements; Forward Skirt, Liquid Oxygen (LOX) tank, Intertank (IT), Liquid Hydrogen (LH2) tank and the Engine Section (ES). Structural Test Articles (STA) for each of these elements are being designed and produced by Boeing at Michoud Assembly Facility located in New Orleans, La. The structural test for the Core Stage STAs (LH2, LOX, IT and ES) are to be conducted by the MSFC Test Laboratory. Additionally, the MSFC Test Laboratory manages the Structural Test Equipment (STE) design and development to support the STAs. It was decided early (April 2012) in the project life that the LH2 and LOX tank STAs would require new test stands and the Engine Section and Intertank would be tested in existing facilities. This decision impacted schedules immediately because the new facilities would require Construction of Facilities (C of F) funds that require congressional approval and long lead times. The Engine Section and Intertank structural test are to be conducted in existing facilities which will limit lead times required to support the first launch of SLS. With a SLS launch date of December, 2017 Boeing had a need date for testing to be complete by September of 2017 to support flight certification requirements. The test facilities were required to be ready by October of 2016 to support test article delivery. The race was on to get the stands ready before Test Article delivery and meet the test complete date of September 2017. This paper documents the past and current design and development phases and the supporting processes, tools, and

Preliminary results on the dynamics of large and flexible space structures in Halo orbits

Science.gov (United States)

Colagrossi, Andrea; Lavagna, Michèle

2017-05-01

The global exploration roadmap suggests, among other ambitious future space programmes, a possible manned outpost in lunar vicinity, to support surface operations and further astronaut training for longer and deeper space missions and transfers. In particular, a Lagrangian point orbit location - in the Earth- Moon system - is suggested for a manned cis-lunar infrastructure; proposal which opens an interesting field of study from the astrodynamics perspective. Literature offers a wide set of scientific research done on orbital dynamics under the Three-Body Problem modelling approach, while less of it includes the attitude dynamics modelling as well. However, whenever a large space structure (ISS-like) is considered, not only the coupled orbit-attitude dynamics should be modelled to run more accurate analyses, but the structural flexibility should be included too. The paper, starting from the well-known Circular Restricted Three-Body Problem formulation, presents some preliminary results obtained by adding a coupled orbit-attitude dynamical model and the effects due to the large structure flexibility. In addition, the most relevant perturbing phenomena, such as the Solar Radiation Pressure (SRP) and the fourth-body (Sun) gravity, are included in the model as well. A multi-body approach has been preferred to represent possible configurations of the large cis-lunar infrastructure: interconnected simple structural elements - such as beams, rods or lumped masses linked by springs - build up the space segment. To better investigate the relevance of the flexibility effects, the lumped parameters approach is compared with a distributed parameters semi-analytical technique. A sensitivity analysis of system dynamics, with respect to different configurations and mechanical properties of the extended structure, is also presented, in order to highlight drivers for the lunar outpost design. Furthermore, a case study for a large and flexible space structure in Halo orbits around

Protein Loop Structure Prediction Using Conformational Space Annealing.

Science.gov (United States)

Heo, Seungryong; Lee, Juyong; Joo, Keehyoung; Shin, Hang-Cheol; Lee, Jooyoung

2017-05-22

We have developed a protein loop structure prediction method by combining a new energy function, which we call E PLM (energy for protein loop modeling), with the conformational space annealing (CSA) global optimization algorithm. The energy function includes stereochemistry, dynamic fragment assembly, distance-scaled finite ideal gas reference (DFIRE), and generalized orientation- and distance-dependent terms. For the conformational search of loop structures, we used the CSA algorithm, which has been quite successful in dealing with various hard global optimization problems. We assessed the performance of E PLM with two widely used loop-decoy sets, Jacobson and RAPPER, and compared the results against the DFIRE potential. The accuracy of model selection from a pool of loop decoys as well as de novo loop modeling starting from randomly generated structures was examined separately. For the selection of a nativelike structure from a decoy set, E PLM was more accurate than DFIRE in the case of the Jacobson set and had similar accuracy in the case of the RAPPER set. In terms of sampling more nativelike loop structures, E PLM outperformed E DFIRE for both decoy sets. This new approach equipped with E PLM and CSA can serve as the state-of-the-art de novo loop modeling method.

The Perspective Structure of Visual Space

Science.gov (United States)

2015-01-01

Luneburg’s model has been the reference for experimental studies of visual space for almost seventy years. His claim for a curved visual space has been a source of inspiration for visual scientists as well as philosophers. The conclusion of many experimental studies has been that Luneburg’s model does not describe visual space in various tasks and conditions. Remarkably, no alternative model has been suggested. The current study explores perspective transformations of Euclidean space as a model for visual space. Computations show that the geometry of perspective spaces is considerably different from that of Euclidean space. Collinearity but not parallelism is preserved in perspective space and angles are not invariant under translation and rotation. Similar relationships have shown to be properties of visual space. Alley experiments performed early in the nineteenth century have been instrumental in hypothesizing curved visual spaces. Alleys were computed in perspective space and compared with reconstructed alleys of Blumenfeld. Parallel alleys were accurately described by perspective geometry. Accurate distance alleys were derived from parallel alleys by adjusting the interstimulus distances according to the size-distance invariance hypothesis. Agreement between computed and experimental alleys and accommodation of experimental results that rejected Luneburg’s model show that perspective space is an appropriate model for how we perceive orientations and angles. The model is also appropriate for perceived distance ratios between stimuli but fails to predict perceived distances. PMID:27648222

Spinning, hurting, still, afraid: Living life spaces with Type I Chiari Malformation.

Science.gov (United States)

Andrews, Gavin J

2018-01-31

Human geography's varied engagement with the brain has involved considerations of the way people know and respond to their environments, and their place-based experiences with emotions, mental illnesses and disorders, intellectual disabilities and particular neurological conditions. This paper argues however that this scholarship could be augmented by, and existing expertise be directed towards, considering physical brain abnormalities and injuries. As a case in point it considers the spatial experience of living with Type 1 Chiari Malformation. Through interviews with four sufferers, the research articulates three domains that they have had to re-negotiate - home space, social space and medical space - emphasizing supportive and challenging aspects of each, as well as meaningful and affective qualities to encounters. The paper concludes with some pointers towards the future study of physical brain abnormalities and injuries and the kinds of knowledge it might create to increase awareness and inform care. Copyright © 2018 Elsevier Ltd. All rights reserved.

Structural concepts for very large (400-meter-diameter) solar concentrators

Science.gov (United States)

Mikulas, Martin M., Jr.; Hedgepeth, John M.

1989-01-01

A general discussion of various types of large space structures is presented. A brief overview of the history of space structures is presented to provide insight into the current state-of-the art. Finally, the results of a structural study to assess the viability of very large solar concentrators are presented. These results include weight, stiffness, part count, and in-space construction time.

A new type of accelerator power supply based on voltage-type space vector PWM rectification technology

International Nuclear Information System (INIS)

Wu, Fengjun; Gao, Daqing; Shi, Chunfeng; Huang, Yuzhen; Cui, Yuan; Yan, Hongbin; Zhang, Huajian; Wang, Bin; Li, Xiaohui

2016-01-01

To solve the problems such as low input power factor, a large number of AC current harmonics and instable DC bus voltage due to the diode or thyristor rectifier used in an accelerator power supply, particularly in the Heavy Ion Research Facility in Lanzhou-Cooler Storage Ring (HIRFL-CSR), we designed and built up a new type of accelerator power supply prototype base on voltage-type space vector PWM (SVPWM) rectification technology. All the control strategies are developed in TMS320C28346, which is a digital signal processor from TI. The experimental results indicate that an accelerator power supply with a SVPWM rectifier can solve the problems above well, and the output performance such as stability, tracking error and ripple current meet the requirements of the design. The achievement of prototype confirms that applying voltage-type SVPWM rectification technology in an accelerator power supply is feasible; and it provides a good reference for design and build of this new type of power supply. - Highlights: • Applying SVPWM rectification technology in an accelerator power supply improves its grid-side performance. • New Topology and its control strategies make an accelerator power supply have bidirectional power flow ability. • Hardware and software of controller provide a good reference for design of this new type of power supply.

A new type of accelerator power supply based on voltage-type space vector PWM rectification technology

Energy Technology Data Exchange (ETDEWEB)

Wu, Fengjun, E-mail: wufengjun@impcas.ac.cn [Institute of Modern Physics, CAS, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Gao, Daqing; Shi, Chunfeng; Huang, Yuzhen [Institute of Modern Physics, CAS, Lanzhou 730000 (China); Cui, Yuan [Institute of Modern Physics, CAS, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Yan, Hongbin [Institute of Modern Physics, CAS, Lanzhou 730000 (China); Zhang, Huajian [Institute of Modern Physics, CAS, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Wang, Bin [University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Xiaohui [Institute of Modern Physics, CAS, Lanzhou 730000 (China)

2016-08-01

To solve the problems such as low input power factor, a large number of AC current harmonics and instable DC bus voltage due to the diode or thyristor rectifier used in an accelerator power supply, particularly in the Heavy Ion Research Facility in Lanzhou-Cooler Storage Ring (HIRFL-CSR), we designed and built up a new type of accelerator power supply prototype base on voltage-type space vector PWM (SVPWM) rectification technology. All the control strategies are developed in TMS320C28346, which is a digital signal processor from TI. The experimental results indicate that an accelerator power supply with a SVPWM rectifier can solve the problems above well, and the output performance such as stability, tracking error and ripple current meet the requirements of the design. The achievement of prototype confirms that applying voltage-type SVPWM rectification technology in an accelerator power supply is feasible; and it provides a good reference for design and build of this new type of power supply. - Highlights: • Applying SVPWM rectification technology in an accelerator power supply improves its grid-side performance. • New Topology and its control strategies make an accelerator power supply have bidirectional power flow ability. • Hardware and software of controller provide a good reference for design of this new type of power supply.

Passive Wireless Sensor System for Space and Structural Health Monitoring, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Aviana Molecular (Aviana) and the University of Central Florida (UCF) propose to develop a Passive Wireless Sensor System (PWSS) for Structural Health Monitoring...

Validation of missed space-group symmetry in X-ray powder diffraction structures with dispersion-corrected density functional theory.

Science.gov (United States)

Hempler, Daniela; Schmidt, Martin U; van de Streek, Jacco

2017-08-01

More than 600 molecular crystal structures with correct, incorrect and uncertain space-group symmetry were energy-minimized with dispersion-corrected density functional theory (DFT-D, PBE-D3). For the purpose of determining the correct space-group symmetry the required tolerance on the atomic coordinates of all non-H atoms is established to be 0.2 Å. For 98.5% of 200 molecular crystal structures published with missed symmetry, the correct space group is identified; there are no false positives. Very small, very symmetrical molecules can end up in artificially high space groups upon energy minimization, although this is easily detected through visual inspection. If the space group of a crystal structure determined from powder diffraction data is ambiguous, energy minimization with DFT-D provides a fast and reliable method to select the correct space group.

Method of the Determination of Exterior Orientation of Sensors in Hilbert Type Space.

Science.gov (United States)

Stępień, Grzegorz

2018-03-17

The following article presents a new isometric transformation algorithm based on the transformation in the newly normed Hilbert type space. The presented method is based on so-called virtual translations, already known in advance, of two relative oblique orthogonal coordinate systems-interior and exterior orientation of sensors-to a common, known in both systems, point. Each of the systems is translated along its axis (the systems have common origins) and at the same time the angular relative orientation of both coordinate systems is constant. The translation of both coordinate systems is defined by the spatial norm determining the length of vectors in the new Hilbert type space. As such, the displacement of two relative oblique orthogonal systems is reduced to zero. This makes it possible to directly calculate the rotation matrix of the sensor. The next and final step is the return translation of the system along an already known track. The method can be used for big rotation angles. The method was verified in laboratory conditions for the test data set and measurement data (field data). The accuracy of the results in the laboratory test is on the level of 10 -6 of the input data. This confirmed the correctness of the assumed calculation method. The method is a further development of the author's 2017 Total Free Station (TFS) transformation to several centroids in Hilbert type space. This is the reason why the method is called Multi-Centroid Isometric Transformation-MCIT. MCIT is very fast and enables, by reducing to zero the translation of two relative oblique orthogonal coordinate systems, direct calculation of the exterior orientation of the sensors.

Method of the Determination of Exterior Orientation of Sensors in Hilbert Type Space

Directory of Open Access Journals (Sweden)

Grzegorz Stępień

2018-03-01

Full Text Available The following article presents a new isometric transformation algorithm based on the transformation in the newly normed Hilbert type space. The presented method is based on so-called virtual translations, already known in advance, of two relative oblique orthogonal coordinate systems—interior and exterior orientation of sensors—to a common, known in both systems, point. Each of the systems is translated along its axis (the systems have common origins and at the same time the angular relative orientation of both coordinate systems is constant. The translation of both coordinate systems is defined by the spatial norm determining the length of vectors in the new Hilbert type space. As such, the displacement of two relative oblique orthogonal systems is reduced to zero. This makes it possible to directly calculate the rotation matrix of the sensor. The next and final step is the return translation of the system along an already known track. The method can be used for big rotation angles. The method was verified in laboratory conditions for the test data set and measurement data (field data. The accuracy of the results in the laboratory test is on the level of 10−6 of the input data. This confirmed the correctness of the assumed calculation method. The method is a further development of the author’s 2017 Total Free Station (TFS transformation to several centroids in Hilbert type space. This is the reason why the method is called Multi-Centroid Isometric Transformation—MCIT. MCIT is very fast and enables, by reducing to zero the translation of two relative oblique orthogonal coordinate systems, direct calculation of the exterior orientation of the sensors.

Yang-Mills solutions and Spin(7)-instantons on cylinders over coset spaces with G2-structure

International Nuclear Information System (INIS)

Haupt, Alexander S.

2016-01-01

We study g-valued Yang-Mills fields on cylinders Z(G/H)=ℝ×G/H, where G/H is a compact seven-dimensional coset space with G 2 -structure, g is the Lie algebra of G, and Z(G/H) inherits a Spin(7)-structure. After imposing a general G-invariance condition, Yang-Mills theory with torsion on Z(G/H) reduces to Newtonian mechanics of a point particle moving in ℝ n under the influence of some quartic potential and possibly additional constraints. The kinematics and dynamics depends on the chosen coset space. We consider in detail three coset spaces with nearly parallel G 2 -structure and four coset spaces with SU(3)-structure. For each case, we analyze the critical points of the potential and present a range of finite-energy solutions. We also study a higher-dimensional analog of the instanton equation. Its solutions yield G-invariant Spin(7)-instanton configurations on Z(G/H), which are special cases of Yang-Mills configurations with torsion.

Measurement and evaluation of the summer microclimate in the semi-enclosed space under a membrane structure

Energy Technology Data Exchange (ETDEWEB)

He, Jiang; Hoyano, Akira [Department of Environmental Science and Technology, Interdisciplinary Graduate School, Tokyo Institute of Technology, 4259-G5-2 Nagatsuta-cho, Midori-ku, Yokohama 226-8502 (Japan)

2010-01-15

This study aims to clarify the summer microclimate in membrane structure buildings with semi-outdoor spaces and develop a computational simulation tool for designing a comfortable urban environment using membrane structures. Field measurements were conducted in a membrane structure building with a semi-outdoor space during a summer period. The present paper describes analysis results of measurement data for vertical distributions of air temperature and velocity under the membrane structure on clear sunny days. The following subjects were also discussed: (1) the effect of solar transmission on the warming of air temperature by the floor under the membrane structure; (2) the temperature reduction effect of ventilation by wind; (3) evaluation of thermal comfort in the living space under the membrane structure in terms of a thermal comfort index (new standard effective temperature: SET*). In order to demonstrate the capability to improve the thermal environment in the test membrane structure building, an evaporative cooling pavement was assumed to be applied to the ground under the membrane structure. The microclimatic modifying effect of this passive cooling strategy was evaluated using a numerical simulation method of coupling computational fluid dynamics (CFD) with a 3D-CAD-based thermal simulation tool developed by the authors' research group. Simulation results show that the proposed simulation method is capable of quantifying spatial distributions of surface temperature, air temperature, air velocity and moisture in the living space under the membrane structure. The thermal comfort index (SET*) can also be estimated using these simulated results. (author)

A Review of Influence of Various Types of Structural Bracing to the Structural Performance of Buildings

Science.gov (United States)

Razak, S. M.; Kong, T. C.; Zainol, N. Z.; Adnan, A.; Azimi, M.

2018-03-01

Excessive lateral drift can contribute significantly towards crack formation, leading to structural damage. The structural damage will in turn reduce the capacity of the structure and weaken it from the intended design capacity. Generally, lateral drift is more pronounced in higher and longer structure, such as high rise buildings and bridges. A typical method employed to control lateral drift is structural bracing, which works by increasing stiffness and stability of structure. This paper reviews the influence of various types of structural bracing to structural performance of buildings. The history of structural bracing is visited and the differences between numerous structural bracing in term of suitability to different types of buildings and loading, mechanisms, technical details, advantages and limitations, and the overall effect on the structural behaviour and performance are dissected. Proper and efficient structural bracing is pertinent for each high rise building as this will lead towards safer, sustainable and more economical buildings, which are cheaper to maintain throughout the life of the buildings in the future.

Bismuth zinc vanadate, BiZn2VO6: New crystal structure type and electronic structure

International Nuclear Information System (INIS)

Eliziario Nunes, Sayonara; Wang, Chun-Hai; So, Karwei; Evans, John S.O.; Evans, Ivana Radosavljević

2015-01-01

We report a combined experimental and computational study of the crystal structure and electronic properties of bismuth zinc vanadate, BiZn 2 VO 6 , known for its visible light photocatalytic activity. The crystal structure has been solved from laboratory powder X-ray diffraction data using the repeated minimisations from random starting values method. BiZn 2 VO 6 adopts a new structure type, based on the following building blocks: corner- and edge-sharing ZnO 4 tetrahedra, ZnO 6 octahedra and VO 4 tetrahedra, and Bi 2 O 12 dimers. It is the only known member of the BiM 2 AO 6 (M=Pb, Ca, Cd, Mn, Zn, Mg, Cu; A=V, P, As) family which does not appear to be structurally closely related to others. The electronic structure of BiZn 2 VO 6 , calculated by DFT methods, shows that it is an indirect gap semiconductor with a calculated band gap of 1.6 eV, which compares favourably to the experimentally measured value of 2.4 eV. - Graphical abstract: The crystal structure of BiZn 2 VO 6 , a new structure type in the BiM 2 AO 6 (M=Mg, Ca, Cd, Cu, Pb, Mn, Zn; A=V, P, As) family. - Highlights: • Structure solution from PXRD data by repeated minimisations from random starting values. • New structure type in the BiM 2 AO 6 (M=Pb, Ca, Cd, Mn, Zn, Mg, Cu; A=V, P, As) family. • Electronic structure calculation

Probabilistic Structural Analysis Methods (PSAM) for select space propulsion system structural components

Science.gov (United States)

Cruse, T. A.

1987-01-01

The objective is the development of several modular structural analysis packages capable of predicting the probabilistic response distribution for key structural variables such as maximum stress, natural frequencies, transient response, etc. The structural analysis packages are to include stochastic modeling of loads, material properties, geometry (tolerances), and boundary conditions. The solution is to be in terms of the cumulative probability of exceedance distribution (CDF) and confidence bounds. Two methods of probability modeling are to be included as well as three types of structural models - probabilistic finite-element method (PFEM); probabilistic approximate analysis methods (PAAM); and probabilistic boundary element methods (PBEM). The purpose in doing probabilistic structural analysis is to provide the designer with a more realistic ability to assess the importance of uncertainty in the response of a high performance structure. Probabilistic Structural Analysis Method (PSAM) tools will estimate structural safety and reliability, while providing the engineer with information on the confidence that should be given to the predicted behavior. Perhaps most critically, the PSAM results will directly provide information on the sensitivity of the design response to those variables which are seen to be uncertain.

Probabilistic Structural Analysis Methods for select space propulsion system structural components (PSAM)

Science.gov (United States)

Cruse, T. A.; Burnside, O. H.; Wu, Y.-T.; Polch, E. Z.; Dias, J. B.

1988-01-01

The objective is the development of several modular structural analysis packages capable of predicting the probabilistic response distribution for key structural variables such as maximum stress, natural frequencies, transient response, etc. The structural analysis packages are to include stochastic modeling of loads, material properties, geometry (tolerances), and boundary conditions. The solution is to be in terms of the cumulative probability of exceedance distribution (CDF) and confidence bounds. Two methods of probability modeling are to be included as well as three types of structural models - probabilistic finite-element method (PFEM); probabilistic approximate analysis methods (PAAM); and probabilistic boundary element methods (PBEM). The purpose in doing probabilistic structural analysis is to provide the designer with a more realistic ability to assess the importance of uncertainty in the response of a high performance structure. Probabilistic Structural Analysis Method (PSAM) tools will estimate structural safety and reliability, while providing the engineer with information on the confidence that should be given to the predicted behavior. Perhaps most critically, the PSAM results will directly provide information on the sensitivity of the design response to those variables which are seen to be uncertain.

Effect of Space Vehicle Structure Vibration on Control Moment Gyroscope Dynamics

Science.gov (United States)

Dobrinskaya, Tatiana

2008-01-01

Control Moment Gyroscopes (CMGs) are used for non-propulsive attitude control of satellites and space stations, including the International Space Station (ISS). CMGs could be essential for future long duration space missions due to the fact that they help to save propellant. CMGs were successfully tested on the ground for many years, and have been successfully used on satellites. However, operations have shown that the CMG service life on the ISS is significantly shorter than predicted. Since the dynamic environment of the ISS differs greatly from the nominal environment of satellites, it was important to analyze how operations specific to the station (dockings and undockings, huge solar array motion, crew exercising, robotic operations, etc) can affect the CMG performance. This task became even more important since the first CMG failure onboard the ISS. The CMG failure resulted in the limitation of the attitude control capabilities, more propellant consumption, and additional operational issues. Therefore, the goal of this work was to find out how the vibrations of a space vehicle structure, caused by a variety of onboard operations, can affect the CMG dynamics and performance. The equations of CMG motion were derived and analyzed for the case when the gyro foundation can vibrate in any direction. The analysis was performed for unbalanced CMG gimbals to match the CMG configuration on ISS. The analysis showed that vehicle structure vibrations can amplify and significantly change the CMG motion if the gyro gimbals are unbalanced in flight. The resonance frequencies were found. It was shown that the resonance effect depends on the magnitude of gimbal imbalance, on the direction of a structure vibration, and on gimbal bearing friction. Computer modeling results of CMG dynamics affected by the external vibration are presented. The results can explain some of the CMG vibration telemetry observed on ISS. This work shows that balancing the CMG gimbals decreases the effect

Structural assessments of plate type support system for APR1400 reactor

Energy Technology Data Exchange (ETDEWEB)

Nguyen, Anh Tung; Namgung, Ihn, E-mail: inamgung@kings.ac.kr

2017-04-01

Highlights: • This paper investigates plate-type support structure for the reactor vessel of the APR 1400. • The tall column supports of APR1400 reactor challenges in seismic and severe accident events. • A plate-type support of reactor vessel was proposed and evaluated based on ASME code. • The plate-type support was assessed to show its higher rigidity than column-type. - Abstract: This paper investigates an alternative form of support structure for the reactor vessel of the APR 1400. The current reactor vessel adopts a four-column support arrangement locating on the cold legs of the vessel. Although having been successfully designed, the tall column structure challenges in seismic events. In addition, for the mitigation of severe accident consequences, the columns inhibit ex-vessel coolant flow, hence the elimination of the support columns proposes extra safety advantages. A plate-type support was proposed and evaluated for the adequacy of meeting the structural stiffness by Finite Element Analysis (FEA) approach. ASME Boiler and Pressure Vessel Code was used to verify the design. The results, which cover thermal and static structural analysis, show stresses are within allowable limits in accordance with the design code. Even the heat conduction area is increased for the plate-type of support system, the results showed that the thermal stresses are within allowable limits. A comparison of natural frequencies and mode shapes for column support and plate-type support were presented as well which showed higher fundamental frequencies for the plate-type support system resulting in greater rigidity of the support system. From the outcome of this research, the plate-type support is proven to be an alternative to current APR column type support design.

Experiences with integral microelectronics on smart structures for space

Science.gov (United States)

Nye, Ted; Casteel, Scott; Navarro, Sergio A.; Kraml, Bob

1995-05-01

One feature of a smart structure implies that some computational and signal processing capability can be performed at a local level, perhaps integral to the controlled structure. This requires electronics with a minimal mechanical influence regarding structural stiffening, heat dissipation, weight, and electrical interface connectivity. The Advanced Controls Technology Experiment II (ACTEX II) space-flight experiments implemented such a local control electronics scheme by utilizing composite smart members with integral processing electronics. These microelectronics, tested to MIL-STD-883B levels, were fabricated with conventional thick film on ceramic multichip module techniques. Kovar housings and aluminum-kapton multilayer insulation was used to protect against harsh space radiation and thermal environments. Development and acceptance testing showed the electronics design was extremely robust, operating in vacuum and at temperature range with minimal gain variations occurring just above room temperatures. Four electronics modules, used for the flight hardware configuration, were connected by a RS-485 2 Mbit per second serial data bus. The data bus was controlled by Actel field programmable gate arrays arranged in a single master, four slave configuration. An Intel 80C196KD microprocessor was chosen as the digital compensator in each controller. It was used to apply a series of selectable biquad filters, implemented via Delta Transforms. Instability in any compensator was expected to appear as large amplitude oscillations in the deployed structure. Thus, over-vibration detection circuitry with automatic output isolation was incorporated into the design. This was not used however, since during experiment integration and test, intentionally induced compensator instabilities resulted in benign mechanical oscillation symptoms. Not too surprisingly, it was determined that instabilities were most detectable by large temperature increases in the electronics, typically

What could the LHC teach us on the structure of space-time?

Directory of Open Access Journals (Sweden)

Triantaphyllou George

2016-01-01

Full Text Available Collision energies of proton beams now available at the LHC increase the probability of discovering the inner works of the Brout-Englert-Higgs (BEH mechanism within the foreseeable future. Nevertheless, they are still several orders of magnitude below the scale where a possible non-trivial structure of space-time would be detectable. Apart from remaining completely silent on the issue of the fundamental nature of elementary particles and the space in which they propagate, one may try to speculate on this matter by carefully extrapolating existing scientific methods and knowledge to Planck energies. In this talk, an effort is made to logically link some potential discoveries at the LHC with specific space-time structures. Since such links are inevitably weak due to the huge energy hierarchy between the electro-weak and the Planck scales, our goal does not exceed a mere presentation of naturalness and self-consistency arguments in favor of some of the possible outcomes, placing particular emphasis on the scenario of the mirror world.

Subdiffusive master equation with space-dependent anomalous exponent and structural instability

Science.gov (United States)

Fedotov, Sergei; Falconer, Steven

2012-03-01

We derive the fractional master equation with space-dependent anomalous exponent. We analyze the asymptotic behavior of the corresponding lattice model both analytically and by Monte Carlo simulation. We show that the subdiffusive fractional equations with constant anomalous exponent μ in a bounded domain [0,L] are not structurally stable with respect to the nonhomogeneous variations of parameter μ. In particular, the Gibbs-Boltzmann distribution is no longer the stationary solution of the fractional Fokker-Planck equation whatever the space variation of the exponent might be. We analyze the random distribution of μ in space and find that in the long-time limit, the probability distribution is highly intermediate in space and the behavior is completely dominated by very unlikely events. We show that subdiffusive fractional equations with the nonuniform random distribution of anomalous exponent is an illustration of a “Black Swan,” the low probability event of the small value of the anomalous exponent that completely dominates the long-time behavior of subdiffusive systems.

Type IX secretion system PorM and gliding machinery GldM form arches spanning the periplasmic space.

Science.gov (United States)

Leone, Philippe; Roche, Jennifer; Vincent, Maxence S; Tran, Quang Hieu; Desmyter, Aline; Cascales, Eric; Kellenberger, Christine; Cambillau, Christian; Roussel, Alain

2018-01-30

Type IX secretion system (T9SS), exclusively present in the Bacteroidetes phylum, has been studied mainly in Flavobacterium johnsoniae and Porphyromonas gingivalis. Among the 18 genes, essential for T9SS function, a group of four, porK-N (P. gingivalis) or gldK-N (F. johnsoniae) belongs to a co-transcribed operon that expresses the T9SS core membrane complex. The central component of this complex, PorM (or GldM), is anchored in the inner membrane by a trans-membrane helix and interacts through the outer membrane PorK-N complex. There is a complete lack of available atomic structures for any component of T9SS, including the PorKLMN complex. Here we report the crystal structure of the GldM and PorM periplasmic domains. Dimeric GldM and PorM, each contain four domains of ~180-Å length that span most of the periplasmic space. These and previously reported results allow us to propose a model of the T9SS core membrane complex as well as its functional behavior.

MEANINGS OF SPACE OF COTTAGE-TYPE RESIDENTIAL CENTER IN MILIEU THERAPY FOR EMOTIONALLY DISTURBED CHILDREN

OpenAIRE

Ishigaki, Aya; Kanno, Minoru; Onoda, Yasuaki; Sakaguchi, Taiyo

2004-01-01

The number of emotionally disturbed children in Japan has been increasing recently; However, only few attempts with an aim at improving children's living space have been made at treatment centers. We conducted some field surveys on the cottage-type residential center to examine the relationship among space, communication, and the effectiveness of therapy. In addition, to clarify conditions of treatment for children with emotional disturbances, the children's daily life with milieu therapy was...

The phase-space structure of nearby dark matter as constrained by the SDSS

International Nuclear Information System (INIS)

Leclercq, Florent; Percival, Will; Jasche, Jens; Lavaux, Guilhem; Wandelt, Benjamin

2017-01-01

Previous studies using numerical simulations have demonstrated that the shape of the cosmic web can be described by studying the Lagrangian displacement field. We extend these analyses, showing that it is now possible to perform a Lagrangian description of cosmic structure in the nearby Universe based on large-scale structure observations. Building upon recent Bayesian large-scale inference of initial conditions, we present a cosmographic analysis of the dark matter distribution and its evolution, referred to as the dark matter phase-space sheet, in the nearby universe as probed by the Sloan Digital Sky Survey main galaxy sample. We consider its stretchings and foldings using a tetrahedral tessellation of the Lagrangian lattice. The method provides extremely accurate estimates of nearby density and velocity fields, even in regions of low galaxy density. It also measures the number of matter streams, and the deformation and parity reversals of fluid elements, which were previously thought inaccessible using observations. We illustrate the approach by showing the phase-space structure of known objects of the nearby Universe such as the Sloan Great Wall, the Coma cluster and the Boötes void. We dissect cosmic structures into four distinct components (voids, sheets, filaments, and clusters), using the Lagrangian classifiers DIVA, ORIGAMI, and a new scheme which we introduce and call LICH. Because these classifiers use information other than the sheer local density, identified structures explicitly carry physical information about their formation history. Accessing the phase-space structure of dark matter in galaxy surveys opens the way for new confrontations of observational data and theoretical models. We have made our data products publicly available.

The phase-space structure of nearby dark matter as constrained by the SDSS

Energy Technology Data Exchange (ETDEWEB)

Leclercq, Florent; Percival, Will [Institute of Cosmology and Gravitation (ICG), University of Portsmouth, Dennis Sciama Building, Burnaby Road, Portsmouth PO1 3FX (United Kingdom); Jasche, Jens [Excellence Cluster Universe, Technische Universität München, Boltzmannstrasse 2, D-85748 Garching (Germany); Lavaux, Guilhem; Wandelt, Benjamin, E-mail: florent.leclercq@polytechnique.org, E-mail: lavaux@iap.fr, E-mail: jasche@iap.fr, E-mail: wandelt@iap.fr, E-mail: will.percival@port.ac.uk [Institut d' Astrophysique de Paris (IAP), UMR 7095, CNRS – UPMC Université Paris 6, Sorbonne Universités, 98bis boulevard Arago, F-75014 Paris (France)

2017-06-01

Previous studies using numerical simulations have demonstrated that the shape of the cosmic web can be described by studying the Lagrangian displacement field. We extend these analyses, showing that it is now possible to perform a Lagrangian description of cosmic structure in the nearby Universe based on large-scale structure observations. Building upon recent Bayesian large-scale inference of initial conditions, we present a cosmographic analysis of the dark matter distribution and its evolution, referred to as the dark matter phase-space sheet, in the nearby universe as probed by the Sloan Digital Sky Survey main galaxy sample. We consider its stretchings and foldings using a tetrahedral tessellation of the Lagrangian lattice. The method provides extremely accurate estimates of nearby density and velocity fields, even in regions of low galaxy density. It also measures the number of matter streams, and the deformation and parity reversals of fluid elements, which were previously thought inaccessible using observations. We illustrate the approach by showing the phase-space structure of known objects of the nearby Universe such as the Sloan Great Wall, the Coma cluster and the Boötes void. We dissect cosmic structures into four distinct components (voids, sheets, filaments, and clusters), using the Lagrangian classifiers DIVA, ORIGAMI, and a new scheme which we introduce and call LICH. Because these classifiers use information other than the sheer local density, identified structures explicitly carry physical information about their formation history. Accessing the phase-space structure of dark matter in galaxy surveys opens the way for new confrontations of observational data and theoretical models. We have made our data products publicly available.

Study the topology of Branciari metric space via the structure proposed by Csaszar

Directory of Open Access Journals (Sweden)

Dong ZHANG

2017-06-01

Full Text Available In this paper, we topologically study the generalized metric space proposed by Branciari [3] via the weak structure proposed by Cs´asz´ar [9, 10], and compare convergent sequences in several different senses. We also introduce the concepts of available points and unavailable points on such structures. Besides, we define the continuous function on structures and investigate further characterizations of continuous functions.

Fermion Systems in Discrete Space-Time Exemplifying the Spontaneous Generation of a Causal Structure

Science.gov (United States)

Diethert, A.; Finster, F.; Schiefeneder, D.

As toy models for space-time at the Planck scale, we consider examples of fermion systems in discrete space-time which are composed of one or two particles defined on two up to nine space-time points. We study the self-organization of the particles as described by a variational principle both analytically and numerically. We find an effect of spontaneous symmetry breaking which leads to the emergence of a discrete causal structure.

Virtual Black Holes and Space-Time Structure

Science.gov (United States)

't Hooft, Gerard

2018-01-01

In the standard formalism of quantum gravity, black holes appear to form statistical distributions of quantum states. Now, however, we can present a theory that yields pure quantum states. It shows how particles entering a black hole can generate firewalls, which however can be removed, replacing them by the `footprints' they produce in the out-going particles. This procedure can preserve the quantum information stored inside and around the black hole. We then focus on a subtle but unavoidable modification of the topology of the Schwarzschild metric: antipodal identification of points on the horizon. If it is true that vacuum fluctuations include virtual black holes, then the structure of space-time is radically different from what is usually thought.

Structural design considerations for an 8-m space telescope

Science.gov (United States)

Arnold, William r., Sr.; Stahl, H. Philip

2009-08-01

NASA's upcoming ARES V launch vehicle, with its' immense payload capacities (both volume and mass) has opened the possibilities for a whole new paradigm of space observatories. It becomes practical to consider a monolith mirror of sufficient size to permit significant scientific advantages, both in collection area and smoothness or figure at a reasonable price. The technologies and engineering to manufacture and test 8 meter class monoliths is mature, with nearly a dozen of such mirrors already in operation around the world. This paper will discuss the design requirements to adapt an 8m meniscus mirror into a Space Telescope System, both launch and operational considerations are included. With objects this massive and structurally sensitive, the mirror design must include all stages of the process. Based upon the experiences of the Hubble Space Telescope, testing and verification at both component and integrated system levels are considered vital to mission success. To this end, two different component level test methods for gravity sag (the so call zero- gravity simulation or test mount) are proposed, with one of these methods suitable for the full up system level testing as well.

Formation of modified TbCu{sub 7} and Th{sub 2}Zn{sub 17} type structures during annealing of mechanical-alloyed Sm-Fe powders

Energy Technology Data Exchange (ETDEWEB)

Teresiak, A.; Kubis, M.; Mattern, N.; Wolf, M.; Mueller, K.-H. [Inst. fuer Festkoerper- und Werkstofforschung, Dresden (Germany)

1998-06-26

Compounds with the nominal composition near Sm{sub 2}Fe{sub 17} were prepared by mechanical alloying starting from the elemental powders and subsequent annealing at temperatures, T{sub A}, between 600 C and 900 C. For crystal structure investigations of the non-equilibrium phases formed at various temperatures, XRD methods with following Rietveld analysis were applied. For T{sub A} between 600 C and 750 C a modified TbCu{sub 7}-type structure of space group P6/mmm was found, in which the Fe(2c) site is replaced by the partially (1/3) and randomly occupied Fe(6l) site. Its approximate composition is SmFe{sub 8.8-9.0}. For T{sub A} between 800 C to 900 C a disordered modified Th{sub 2}Zn{sub 17} structure (space group R anti 3m) was found that is formed by introducing additional randomly occupied Fe (6c) and Sm(3a) positions, respectively. The degree of order of Sm atoms and Fe-dumbbells along the c-direction increases with increasing T{sub A}. A decrease in the Fe concentration in the cell is observed for increasing T{sub A}. The completely ordered stoichiometric Th{sub 2}Zn{sub 17}-type structure could not be reached by annealing samples prepared from the ball-milled elemental powders. (orig.) 20 refs.

Crystal structure of a copper-transporting PIB-type ATPase

DEFF Research Database (Denmark)

Gourdon, Pontus Emanuel; Liu, Xiang-Yu; Skjørringe, Tina

2011-01-01

Heavy-metal homeostasis and detoxification is crucial for cell viability. P-type ATPases of the class IB (PIB) are essential in these processes, actively extruding heavy metals from the cytoplasm of cells. Here we present the structure of a PIB-ATPase, a Legionella pneumophila CopA Cu(+)-ATPase, ......Heavy-metal homeostasis and detoxification is crucial for cell viability. P-type ATPases of the class IB (PIB) are essential in these processes, actively extruding heavy metals from the cytoplasm of cells. Here we present the structure of a PIB-ATPase, a Legionella pneumophila CopA Cu...

Eyjafjallajokull Volcano Plume Particle-Type Characterization from Space-Based Multi-angle Imaging

Science.gov (United States)

Kahn, Ralph A.; Limbacher, James

2012-01-01

The Multi-angle Imaging SpectroRadiometer (MISR) Research Aerosol algorithm makes it possible to study individual aerosol plumes in considerable detail. From the MISR data for two optically thick, near-source plumes from the spring 2010 eruption of the Eyjafjallaj kull volcano, we map aerosol optical depth (AOD) gradients and changing aerosol particle types with this algorithm; several days downwind, we identify the occurrence of volcanic ash particles and retrieve AOD, demonstrating the extent and the limits of ash detection and mapping capability with the multi-angle, multi-spectral imaging data. Retrieved volcanic plume AOD and particle microphysical properties are distinct from background values near-source, as well as for overwater cases several days downwind. The results also provide some indication that as they evolve, plume particles brighten, and average particle size decreases. Such detailed mapping offers context for suborbital plume observations having much more limited sampling. The MISR Standard aerosol product identified similar trends in plume properties as the Research algorithm, though with much smaller differences compared to background, and it does not resolve plume structure. Better optical analogs of non-spherical volcanic ash, and coincident suborbital data to validate the satellite retrieval results, are the factors most important for further advancing the remote sensing of volcanic ash plumes from space.

Real-space local polynomial basis for solid-state electronic-structure calculations: A finite-element approach

International Nuclear Information System (INIS)

Pask, J.E.; Klein, B.M.; Fong, C.Y.; Sterne, P.A.

1999-01-01

We present an approach to solid-state electronic-structure calculations based on the finite-element method. In this method, the basis functions are strictly local, piecewise polynomials. Because the basis is composed of polynomials, the method is completely general and its convergence can be controlled systematically. Because the basis functions are strictly local in real space, the method allows for variable resolution in real space; produces sparse, structured matrices, enabling the effective use of iterative solution methods; and is well suited to parallel implementation. The method thus combines the significant advantages of both real-space-grid and basis-oriented approaches and so promises to be particularly well suited for large, accurate ab initio calculations. We develop the theory of our approach in detail, discuss advantages and disadvantages, and report initial results, including electronic band structures and details of the convergence of the method. copyright 1999 The American Physical Society

Spacing grid intended for nuclear reactor fuel assemblies

International Nuclear Information System (INIS)

Patterson, J.F.; Flora, B.S.

1977-01-01

This invention concerns a new improved type of spacing grid that can be used in nuclear reactor fuel assemblies. Under the invention a spacing grid is provided, preferably of the bimetallic type. This grid includes a set of flexible inconel strips positioned by structural 'zircalloy' fittings, having relatively low neutron absorption characteristics in comparison with systems where the flexible strips are welded in position, or where the spring forms an integral part of the structure. The openings for the fuel elements which are defined by the structural fittings intercrossing are fitted internally with bosses which work in conjunction with a spring directed downwards as from the flexible strip so as to position the individual fuel rods in their respective openings inside the grid structure. These flexible strips are arranged in rows extending in directions which depend on the particular design of the fuel asembly and which contain flexible components so distributed that the loads of the individual springs tend to equalize each other mutually. The reaction load exerting itself on the supporting structure is reduced to the minimum, and this results in a lesser distortion in the reactor and an equalisation of the spring loads [fr

Permittivity and Permeability for Floquet-Bloch Space Harmonics in Infinite 1D Magneto-Dielectric Periodic Structures

DEFF Research Database (Denmark)

Breinbjerg, Olav; Yaghjian, Arthur D.

2014-01-01

-Bloch space harmonics. We discuss how space harmonic permittivity and permeability can be expressed in seemingly different though equivalent forms, and we investigate these parameters of the zeroeth order space harmonic for a particular 1D periodic structure that is based on a previously reported 3D periodic...

Classification of compact homogeneous spaces with invariant G(2)-structures

Czech Academy of Sciences Publication Activity Database

Le, Hong-Van; Munir, M.

2012-01-01

Roč. 12, č. 2 (2012), s. 303-328 ISSN 1615-715X R&D Projects: GA AV ČR IAA100190701 Institutional support: RVO:67985840 Keywords : compact homogeneous space * G(2)-structure Subject RIV: BA - General Mathematics Impact factor: 0.371, year: 2012 http://www.degruyter.com/view/j/advg.2012.12.issue-2/advgeom.2011.054/advgeom.2011.054. xml

A Novel Double-Piston Magnetorheological Damper for Space Truss Structures Vibration Suppression

OpenAIRE

Qiang Wang; Mehdi Ahmadian; Zhaobo Chen

2014-01-01

The design, fabrication, and testing of a new double-piston MR damper for space applications are discussed. The design concept for the damper is described in detail. The electromagnetic analysis of the design and the fabrication of the MR damper are also presented. The design analysis shows that the damper meets the weight and size requirements for being included in a space truss structure. The prototype design is tested in a damper dynamometer. The test results show that the damper can provi...

Assessment of urban green space structures and their quality from a multidimensional perspective.

Science.gov (United States)

Daniels, Benjamin; Zaunbrecher, Barbara S; Paas, Bastian; Ottermanns, Richard; Ziefle, Martina; Roß-Nickoll, Martina

2018-02-15

Facing the growing amount of people living in cities and, at the same time, the need for a compact and sustainable urban development to mitigate urban sprawl, it becomes increasingly important that green spaces in compact cities are designed to meet the various needs within an urban environment. Urban green spaces have a multitude of functions: Maintaining ecological processes and resulting services, e.g. providing habitat for animals and plants, providing a beneficial city microclimate as well as recreational space for citizens. Regarding these requirements, currently existing assessment procedures for green spaces have some major shortcomings, which are discussed in this paper. It is argued why a more detailed spatial level as well as a distinction between natural and artificial varieties of structural elements is justified and needed and how the assessment of urban green spaces benefits from the multidimensional perspective that is applied. By analyzing a selection of structural elements from an ecological, microclimatic and social perspective, indicator values are derived and a new, holistic metrics 1 is proposed. The results of the integrated analysis led to two major findings: first, that for some elements, the evaluation differs to a great extent between the different perspectives (disciplines) and second, that natural and artificial varieties are, in most cases, evaluated considerably different from each other. The differences between the perspectives call for an integrative planning policy which acknowledges the varying contribution of a structural element to different purposes (ecological, microclimatic, social) as well as a discussion about the prioritization of those purposes. The differences in the evaluation of natural vs. artificial elements verify the assumption that indicators which consider only generic elements fail to account for those refinements and are thus less suitable for planning and assessment purposes. Implications, challenges and

UNDERSTANDING THE STRUCTURE OF THE HOT INTERSTELLAR MEDIUM IN NORMAL EARLY-TYPE GALAXIES.

Science.gov (United States)

Traynor, Liam; Kim, Dong-Woo; Chandra Galaxy Atlas

2018-01-01

The hot interstellar medium (ISM) of early-type galaxies (ETG's) provides crucial insight into the understanding of their formation and evolution. Mechanisms such as type Ia supernovae heating, AGN feedback, deepening potential depth through dark matter assembly and ramp-pressure stripping are known to affect the structure of the ISM. By using temperature maps and radial temperature profiles of the hot ISM from ~70 ETG's with archival Chandra data, it is possible to classify the galaxy's ISM into common structural types. This is extended by using 3D fitting of the radial temperature profile in order to provide models that further constrain the structural types. Five structural types are present, negative (temperature decreases with radii), positive (temperature increases with radii), hybrid-dip (temperature decreases at small radii and increases at large radii), hybrid-bump (inverse of hybrid-dip) and quasi-isothermal (temperature is constant at all radii). This work will be continued by 1) determining which mechanisms are present in which galaxies and 2) analysing the model parameters between galaxies within each structural type to determine whether each type can be described by a single set of model parameters, indicating that the same physical processes are responsible for creating that structural type.

The complex structures on the coadjoint orbit spaces of Diff(S1) and on Bers' universal Teichmueller space are compatible

International Nuclear Information System (INIS)

Nag, S.; Verjovsky, A.

1988-08-01

Precisely two coadjoint orbit spaces of the group of string reparametrizations carry in a natural way the structure of infinite dimensional, holomorphically homogeneous complex manifolds. These are M 1 =Diff(S 1 )/Rot(S 1 ) and M 2 =Diff(S 1 )/Mo-barb(S 1 ). M 2 can be naturally considered as (embedded in) the classical univeral Teichmueller space T(Δ), simply by noting that a diffeomorphism of S 1 is a quasi-symmetric homeomorphism. T(Δ) is itself a homomorphically homogeneous complex Banach manifold. We prove that the inclusion of M 2 in T(Δ) is complex analytic. Every Teichmueller space of finite or infinite dimension is contained canonically and holomorphically in T(Δ). Our result thus appears to connect the loop space approach to bosonic string theory with the sum-over moduli (Polyakov path integral) approach. (author). 12 refs

Compact state-space models for complex superconducting radio-frequency structures based on model order reduction and concatenation methods

International Nuclear Information System (INIS)

Flisgen, Thomas

2015-01-01

The modeling of large chains of superconducting cavities with couplers is a challenging task in computational electrical engineering. The direct numerical treatment of these structures can easily lead to problems with more than ten million degrees of freedom. Problems of this complexity are typically solved with the help of parallel programs running on supercomputing infrastructures. However, these infrastructures are expensive to purchase, to operate, and to maintain. The aim of this thesis is to introduce and to validate an approach which allows for modeling large structures on a standard workstation. The novel technique is called State-Space Concatenations and is based on the decomposition of the complete structure into individual segments. The radio-frequency properties of the generated segments are described by a set of state-space equations which either emerge from analytical considerations or from numerical discretization schemes. The model order of these equations is reduced using dedicated model order reduction techniques. In a final step, the reduced-order state-space models of the segments are concatenated in accordance with the topology of the complete structure. The concatenation is based on algebraic continuity constraints of electric and magnetic fields on the decomposition planes and results in a compact state-space system of the complete radio-frequency structure. Compared to the original problem, the number of degrees of freedom is drastically reduced, i.e. a problem with more than ten million degrees of freedom can be reduced on a standard workstation to a problem with less than one thousand degrees of freedom. The final state-space system allows for determining frequency-domain transfer functions, field distributions, resonances, and quality factors of the complete structure in a convenient manner. This thesis presents the theory of the state-space concatenation approach and discusses several validation and application examples. The examples

Methodologies for Verification and Validation of Space Launch System (SLS) Structural Dynamic Models

Science.gov (United States)

Coppolino, Robert N.

2018-01-01

Responses to challenges associated with verification and validation (V&V) of Space Launch System (SLS) structural dynamics models are presented in this paper. Four methodologies addressing specific requirements for V&V are discussed. (1) Residual Mode Augmentation (RMA), which has gained acceptance by various principals in the NASA community, defines efficient and accurate FEM modal sensitivity models that are useful in test-analysis correlation and reconciliation and parametric uncertainty studies. (2) Modified Guyan Reduction (MGR) and Harmonic Reduction (HR, introduced in 1976), developed to remedy difficulties encountered with the widely used Classical Guyan Reduction (CGR) method, are presented. MGR and HR are particularly relevant for estimation of "body dominant" target modes of shell-type SLS assemblies that have numerous "body", "breathing" and local component constituents. Realities associated with configuration features and "imperfections" cause "body" and "breathing" mode characteristics to mix resulting in a lack of clarity in the understanding and correlation of FEM- and test-derived modal data. (3) Mode Consolidation (MC) is a newly introduced procedure designed to effectively "de-feature" FEM and experimental modes of detailed structural shell assemblies for unambiguous estimation of "body" dominant target modes. Finally, (4) Experimental Mode Verification (EMV) is a procedure that addresses ambiguities associated with experimental modal analysis of complex structural systems. Specifically, EMV directly separates well-defined modal data from spurious and poorly excited modal data employing newly introduced graphical and coherence metrics.

Experimental validation of tape springs to be used as thin-walled space structures

Science.gov (United States)

Oberst, S.; Tuttle, S. L.; Griffin, D.; Lambert, A.; Boyce, R. R.

2018-04-01

With the advent of standardised launch geometries and off-the-shelf payloads, space programs utilising nano-satellite platforms are growing worldwide. Thin-walled, flexible and self-deployable structures are commonly used for antennae, instrument booms or solar panels owing to their lightweight, ideal packaging characteristics and near zero energy consumption. However their behaviour in space, in particular in Low Earth Orbits with continually changing environmental conditions, raises many questions. Accurate numerical models, which are often not available due to the difficulty of experimental testing under 1g-conditions, are needed to answer these questions. In this study, we present on-earth experimental validations, as a starting point to study the response of a tape spring as a representative of thin-walled flexible structures under static and vibrational loading. Material parameters of tape springs in a singly (straight, open cylinder) and a doubly curved design, are compared to each other by combining finite element calculations, with experimental laser vibrometry within a single and multi-stage model updating approach. While the determination of the Young's modulus is unproblematic, the damping is found to be inversely proportional to deployment length. With updated material properties the buckling instability margin is calculated using different slenderness ratios. Results indicate a high sensitivity of thin-walled structures to miniscule perturbations, which makes proper experimental testing a key requirement for stability prediction on thin-elastic space structures. The doubly curved tape spring provides closer agreement with experimental results than a straight tape spring design.

Interactive computer graphics and its role in control system design of large space structures

Science.gov (United States)

Reddy, A. S. S. R.

1985-01-01

This paper attempts to show the relevance of interactive computer graphics in the design of control systems to maintain attitude and shape of large space structures to accomplish the required mission objectives. The typical phases of control system design, starting from the physical model such as modeling the dynamics, modal analysis, and control system design methodology are reviewed and the need of the interactive computer graphics is demonstrated. Typical constituent parts of large space structures such as free-free beams and free-free plates are used to demonstrate the complexity of the control system design and the effectiveness of the interactive computer graphics.

Taylor coefficients and coefficient multipliers of Hardy and Bergman-type spaces

CERN Document Server

Jevtić, Miroljub; Arsenović, Miloš

2016-01-01

This book provides a systematic overview of the theory of Taylor coefficients of functions in some classical spaces of analytic functions and especially of the coefficient multipliers between spaces of Hardy type. Offering a comprehensive reference guide to the subject, it is the first of its kind in this area. After several introductory chapters covering the basic material, a large variety of results obtained over the past 80 years, including the most recent ones, are treated in detail. Several chapters end with discussions of practical applications and related topics that graduate students and experts in other subjects may find useful for their own purposes. Thus, a further aim of the book is to communicate to non-specialists some concrete facts that may be of value in their own work. The book can also be used as a textbook or a supplementary reference for an advanced graduate course. It is primarily intended for specialists in complex and functional analysis, graduate students, and experts in other related...

X-ray structure of a soluble Rieske-type ferredoxin from Mus musculus

International Nuclear Information System (INIS)

Levin, Elena J.; Elsen, Nathaniel L.; Seder, Kory D.; McCoy, Jason G.; Fox, Brian G.; Phillips Jr, George N.

2008-01-01

The X-ray crystal structure of a soluble Rieske ferredoxin from M. musculus was solved at 2.07 Å resolution, revealing an iron–sulfur cluster-binding domain with similar architecture to the Rieske-type domains of bacterial aromatic dioxygenases. The ferredoxin was also shown to be capable of accepting electrons from both eukaryotic and prokaryotic oxidoreductases. The 2.07 Å resolution X-ray crystal structure of a soluble Rieske-type ferredoxin from Mus musculus encoded by the gene Mm.266515 is reported. Although they are present as covalent domains in eukaryotic membrane oxidase complexes, soluble Rieske-type ferredoxins have not previously been observed in eukaryotes. The overall structure of the mouse Rieske-type ferredoxin is typical of this class of iron–sulfur proteins and consists of a larger partial β-barrel domain and a smaller domain containing Cys57, His59, Cys80 and His83 that binds the [2Fe–2S] cluster. The S atoms of the cluster are hydrogen-bonded by six backbone amide N atoms in a pattern typical of membrane-bound high-potential eukaryotic respiratory Rieske ferredoxins. However, phylogenetic analysis suggested that the mouse Rieske-type ferredoxin was more closely related to bacterial Rieske-type ferredoxins. Correspondingly, the structure revealed an extended loop most similar to that seen in Rieske-type ferredoxin subunits of bacterial aromatic dioxygenases, including the positioning of an aromatic side chain (Tyr85) between this loop and the [2Fe–2S] cluster. The mouse Rieske-type ferredoxin was shown to be capable of accepting electrons from both eukaryotic and prokaryotic oxidoreductases, although it was unable to serve as an electron donor for a bacterial monooxygenase complex. The human homolog of mouse Rieske-type ferredoxin was also cloned and purified. It behaved identically to mouse Rieske-type ferredoxin in all biochemical characterizations but did not crystallize. Based on its high sequence identity, the structure of the

PROVIDING SERVICEABILITY OF STRUCTURAL BEARING TYPES FOR ROADWAY BRIDGES

Directory of Open Access Journals (Sweden)

R. I. Polyuga

2010-03-01

Full Text Available In the article the description of structural bearing types for roadway bridges and their classification is given. Special attention is paid to effective bearings with elastomeric materials – rubber, pot, spherical ones. Characteristic defects of structural bearings and demands of serviceability are noticed.

Cryo-EM structures of two bovine adenovirus type 3 intermediates

International Nuclear Information System (INIS)

Cheng, Lingpeng; Huang, Xiaoxing; Li, Xiaomin; Xiong, Wei; Sun, Wei; Yang, Chongwen; Zhang, Kai; Wang, Ying; Liu, Hongrong; Huang, Xiaojun; Ji, Gang; Sun, Fei; Zheng, Congyi; Zhu, Ping

2014-01-01

Adenoviruses (Ads) infect hosts from all vertebrate species and have been investigated as vaccine vectors. We report here near-atomic structures of two bovine Ad type 3 (BAd3) intermediates obtained by cryo-electron microscopy. A comparison between the two intermediate structures reveals that the differences are localized in the fivefold vertex region, while their facet structures are identical. The overall facet structure of BAd3 exhibits a similar structure to human Ads; however, BAd3 protein IX has a unique conformation. Mass spectrometry and cryo-electron tomography analyses indicate that one intermediate structure represents the stage during DNA encapsidation, whilst the other intermediate structure represents a later stage. These results also suggest that cleavage of precursor protein VI occurs during, rather than after, the DNA encapsidation process. Overall, our results provide insights into the mechanism of Ad assembly, and allow the first structural comparison between human and nonhuman Ads at backbone level. - Highlights: • First structure of bovine adenovirus type 3. • Some channels are located at the vertex of intermediate during DNA encapsidation. • Protein IX exhibits a unique conformation of trimeric coiled–coiled structure. • Cleavage of precursor protein VI occurs during the DNA encapsidation process

Cryo-EM structures of two bovine adenovirus type 3 intermediates

Energy Technology Data Exchange (ETDEWEB)

Cheng, Lingpeng; Huang, Xiaoxing; Li, Xiaomin [National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101 (China); Xiong, Wei [State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Luo-jia-shan, Wuhan, Hubei 430072 (China); Sun, Wei; Yang, Chongwen; Zhang, Kai; Wang, Ying [National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101 (China); Liu, Hongrong [College of Physics and Information Science, Hunan Normal University, Changsha, Hunan 410081 (China); Huang, Xiaojun; Ji, Gang; Sun, Fei [National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101 (China); Zheng, Congyi, E-mail: cctcc202@whu.edu.cn [State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Luo-jia-shan, Wuhan, Hubei 430072 (China); Zhu, Ping, E-mail: zhup@ibp.ac.cn [National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101 (China)

2014-02-15

Adenoviruses (Ads) infect hosts from all vertebrate species and have been investigated as vaccine vectors. We report here near-atomic structures of two bovine Ad type 3 (BAd3) intermediates obtained by cryo-electron microscopy. A comparison between the two intermediate structures reveals that the differences are localized in the fivefold vertex region, while their facet structures are identical. The overall facet structure of BAd3 exhibits a similar structure to human Ads; however, BAd3 protein IX has a unique conformation. Mass spectrometry and cryo-electron tomography analyses indicate that one intermediate structure represents the stage during DNA encapsidation, whilst the other intermediate structure represents a later stage. These results also suggest that cleavage of precursor protein VI occurs during, rather than after, the DNA encapsidation process. Overall, our results provide insights into the mechanism of Ad assembly, and allow the first structural comparison between human and nonhuman Ads at backbone level. - Highlights: • First structure of bovine adenovirus type 3. • Some channels are located at the vertex of intermediate during DNA encapsidation. • Protein IX exhibits a unique conformation of trimeric coiled–coiled structure. • Cleavage of precursor protein VI occurs during the DNA encapsidation process.

Quantum mechanical path integrals in curved spaces and the type-A trace anomaly

Energy Technology Data Exchange (ETDEWEB)

Bastianelli, Fiorenzo [Dipartimento di Fisica ed Astronomia, Università di Bologna,via Irnerio 46, I-40126 Bologna (Italy); INFN, Sezione di Bologna,via Irnerio 46, I-40126 Bologna (Italy); Corradini, Olindo [Dipartimento di Scienze Fisiche, Informatiche e Matematiche,Università di Modena e Reggio Emilia,Via Campi 213/A, I-41125 Modena (Italy); INFN, Sezione di Bologna,via Irnerio 46, I-40126 Bologna (Italy); Vassura, Edoardo [Dipartimento di Fisica ed Astronomia, Università di Bologna,via Irnerio 46, I-40126 Bologna (Italy); INFN, Sezione di Bologna,via Irnerio 46, I-40126 Bologna (Italy)

2017-04-10

Path integrals for particles in curved spaces can be used to compute trace anomalies in quantum field theories, and more generally to study properties of quantum fields coupled to gravity in first quantization. While their construction in arbitrary coordinates is well understood, and known to require the use of a regularization scheme, in this article we take up an old proposal of constructing the path integral by using Riemann normal coordinates. The method assumes that curvature effects are taken care of by a scalar effective potential, so that the particle lagrangian is reduced to that of a linear sigma model interacting with the effective potential. After fixing the correct effective potential, we test the construction on spaces of maximal symmetry and use it to compute heat kernel coefficients and type-A trace anomalies for a scalar field in arbitrary dimensions up to d=12. The results agree with expected ones, which are reproduced with great efficiency and extended to higher orders. We prove explicitly the validity of the simplified path integral on maximally symmetric spaces. This simplified path integral might be of further use in worldline applications, though its application on spaces of arbitrary geometry remains unclear.

TESTING GARCH-X TYPE MODELS

DEFF Research Database (Denmark)

Pedersen, Rasmus Søndergaard; Rahbek, Anders

2017-01-01

We present novel theory for testing for reduction of GARCH-X type models with an exogenous (X) covariate to standard GARCH type models. To deal with the problems of potential nuisance parameters on the boundary of the parameter space as well as lack of identification under the null, we exploit...... a noticeable property of specific zero-entries in the inverse information of the GARCH-X type models. Specifically, we consider sequential testing based on two likelihood ratio tests and as demonstrated the structure of the inverse information implies that the proposed test neither depends on whether...... the nuisance parameters lie on the boundary of the parameter space, nor on lack of identification. Our general results on GARCH-X type models are applied to Gaussian based GARCH-X models, GARCH-X models with Student's t-distributed innovations as well as the integer-valued GARCH-X (PAR-X) models....

Phase space methods for Majorana fermions

Science.gov (United States)

Rushin Joseph, Ria; Rosales-Zárate, Laura E. C.; Drummond, Peter D.

2018-06-01

Fermionic phase space representations are a promising method for studying correlated fermion systems. The fermionic Q-function and P-function have been defined using Gaussian operators of fermion annihilation and creation operators. The resulting phase-space of covariance matrices belongs to the symmetry class D, one of the non-standard symmetry classes. This was originally proposed to study mesoscopic normal-metal-superconducting hybrid structures, which is the type of structure that has led to recent experimental observations of Majorana fermions. Under a unitary transformation, it is possible to express these Gaussian operators using real anti-symmetric matrices and Majorana operators, which are much simpler mathematical objects. We derive differential identities involving Majorana fermion operators and an antisymmetric matrix which are relevant to the derivation of the corresponding Fokker–Planck equations on symmetric space. These enable stochastic simulations either in real or imaginary time. This formalism has direct relevance to the study of fermionic systems in which there are Majorana type excitations, and is an alternative to using expansions involving conventional Fermi operators. The approach is illustrated by showing how a linear coupled Hamiltonian as used to study topological excitations can be transformed to Fokker–Planck and stochastic equation form, including dissipation through particle losses.

Relationship Structures and Semantic Type Assignments of the UMLS Enriched Semantic Network

Science.gov (United States)

Zhang, Li; Halper, Michael; Perl, Yehoshua; Geller, James; Cimino, James J.

2005-01-01

Objective: The Enriched Semantic Network (ESN) was introduced as an extension of the Unified Medical Language System (UMLS) Semantic Network (SN). Its multiple subsumption configuration and concomitant multiple inheritance make the ESN's relationship structures and semantic type assignments different from those of the SN. A technique for deriving the relationship structures of the ESN's semantic types and an automated technique for deriving the ESN's semantic type assignments from those of the SN are presented. Design: The technique to derive the ESN's relationship structures finds all newly inherited relationships in the ESN. All such relationships are audited for semantic validity, and the blocking mechanism is used to block invalid relationships. The mapping technique to derive the ESN's semantic type assignments uses current SN semantic type assignments and preserves nonredundant categorizations, while preventing new redundant categorizations. Results: Among the 426 newly inherited relationships, 326 are deemed valid. Seven blockings are applied to avoid inheritance of the 100 invalid relationships. Sixteen semantic types have different relationship structures in the ESN as compared to those in the SN. The mapping of semantic type assignments from the SN to the ESN avoids the generation of 26,950 redundant categorizations. The resulting ESN contains 138 semantic types, 149 IS-A links, 7,303 relationships, and 1,013,876 semantic type assignments. Conclusion: The ESN's multiple inheritance provides more complete relationship structures than in the SN. The ESN's semantic type assignments avoid the existing redundant categorizations appearing in the SN and prevent new ones that might arise due to multiple parents. Compared to the SN, the ESN provides a more accurate unifying semantic abstraction of the UMLS Metathesaurus. PMID:16049233

Spectral synthesis in certain spaces of entire functions of exponential type and its applications

International Nuclear Information System (INIS)

Odinokov, O V

2000-01-01

We consider certain spaces P Ω of entire functions of exponential type in C n associated with a domain Ω element of R n that are in fact Laplace transforms of distributions in Ω. It is shown that any shift-invariant subspace of these functions admits spectral synthesis, that is, coincides with the closure of the linear span of the exponential polynomials contained in it. As an application of this result, we describe the solution space in P Ω of a system of homogeneous equations of infinite order for differential operators with characteristic functions infinitely differentiable in Ω

On the modular structure of the genus-one Type II superstring low energy expansion

International Nuclear Information System (INIS)

D’Hoker, Eric; Green, Michael B.; Vanhove, Pierre

2015-01-01

The analytic contribution to the low energy expansion of Type II string amplitudes at genus-one is a power series in space-time derivatives with coefficients that are determined by integrals of modular functions over the complex structure modulus of the world-sheet torus. These modular functions are associated with world-sheet vacuum Feynman diagrams and given by multiple sums over the discrete momenta on the torus. In this paper we exhibit exact differential and algebraic relations for a certain infinite class of such modular functions by showing that they satisfy Laplace eigenvalue equations with inhomogeneous terms that are polynomial in non-holomorphic Eisenstein series. Furthermore, we argue that the set of modular functions that contribute to the coefficients of interactions up to order D 10 R 4 are linear sums of functions in this class and quadratic polynomials in Eisenstein series and odd Riemann zeta values. Integration over the complex structure results in coefficients of the low energy expansion that are rational numbers multiplying monomials in odd Riemann zeta values.

On the modular structure of the genus-one Type II superstring low energy expansion

Energy Technology Data Exchange (ETDEWEB)

D’Hoker, Eric [Department of Physics and Astronomy,University of California, Los Angeles, CA 90095 (United States); Green, Michael B. [Department of Applied Mathematics and Theoretical Physics,Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Vanhove, Pierre [Institut des Hautes Études Scientifiques, Le Bois-Marie, 35 route de Chartres,F-91440 Bures-sur-Yvette (France); Institut de physique théorique, Université Paris Saclay, CEA, CNRS,F-91191 Gif-sur-Yvette (France)

2015-08-11

The analytic contribution to the low energy expansion of Type II string amplitudes at genus-one is a power series in space-time derivatives with coefficients that are determined by integrals of modular functions over the complex structure modulus of the world-sheet torus. These modular functions are associated with world-sheet vacuum Feynman diagrams and given by multiple sums over the discrete momenta on the torus. In this paper we exhibit exact differential and algebraic relations for a certain infinite class of such modular functions by showing that they satisfy Laplace eigenvalue equations with inhomogeneous terms that are polynomial in non-holomorphic Eisenstein series. Furthermore, we argue that the set of modular functions that contribute to the coefficients of interactions up to order D{sup 10}R{sup 4} are linear sums of functions in this class and quadratic polynomials in Eisenstein series and odd Riemann zeta values. Integration over the complex structure results in coefficients of the low energy expansion that are rational numbers multiplying monomials in odd Riemann zeta values.

Diversity, assembly and regulation of archaeal type IV pili-like and non-type-IV pili-like surface structures.

Science.gov (United States)

Lassak, Kerstin; Ghosh, Abhrajyoti; Albers, Sonja-Verena

2012-01-01

Archaea have evolved fascinating surface structures allowing rapid adaptation to changing environments. The archaeal surface appendages display such diverse biological roles as motility, adhesion, biofilm formation, exchange of genetic material and species-specific interactions and, in turn, increase fitness of the cells. Intriguingly, despite sharing the same functions with their bacterial counterparts, the assembly mechanism of many archaeal surface structures is rather related to assembly of bacterial type IV pili. This review summarizes our state-of-the-art knowledge about unique structural and biochemical properties of archaeal surface appendages with a particular focus on archaeal type IV pili-like structures. The latter comprise not only widely distributed archaella (formerly known as archaeal flagella), but also different highly specialized archaeal pili, which are often restricted to certain species. Recent findings regarding assembly mechanisms, structural aspects and physiological roles of these type IV pili-like structures will be discussed in detail. Recently, first regulatory proteins involved in transition from both planktonic to sessile lifestyle and in assembly of archaella were identified. To conclude, we provide novel insights into regulatory mechanisms underlying the assembly of archaeal surface structures. Copyright © 2012. Published by Elsevier Masson SAS.

PREPARING THE PUBLIC FOR COMMERCIALIZATION AND GUIDANCE OF STRUCTURAL MEDIA SPACE TOWARDS ITS FUSION WITH ADVERTISING SPACE

Directory of Open Access Journals (Sweden)

Marina Đukić

2015-07-01

Full Text Available Through genre structure analysis of the Television´s Zagreb First Channel schedule from the beginning of 1970´s till the end of the 1980´s accompanied by analysis of advertising in same period, the paper will examine the ways and intensity of commercialization entrance in Croatian media space dominated then by state media. Television schedule genre change and the broadcast of economic propaganda program will point out the different character of the television. It can be said that it will serve for preparing the public for commercialization entrance and guidance of structural media space towards its fusion with advertising one. The assumption is that in spite of the TV schedule change, which was in economic sense accompanied by economy reforms in order to establish market economy, the public wasn´t yet delivered to advertisers. One of the clarification lies in the role of the media, which then had revolutionary function with main purpose of not the voters’ generation but only to create patriots. The paper will reproduce a kind of public transformation genesis from latent status in state guided media system to same status of latent consumers in dual media model.

Anisotropic hardy spaces of Musielak-Orlicz type with applications to boundedness of sublinear operators.

Science.gov (United States)

Li, Baode; Yang, Dachun; Yuan, Wen

2014-01-01

Let φ : ℝ(n) × [0, ∞)→[0, ∞) be a Musielak-Orlicz function and A an expansive dilation. In this paper, the authors introduce the anisotropic Hardy space of Musielak-Orlicz type, H(A)(φ)(ℝ(n)), via the grand maximal function. The authors then obtain some real-variable characterizations of H(A)(φ)(ℝ(n)) in terms of the radial, the nontangential, and the tangential maximal functions, which generalize the known results on the anisotropic Hardy space H(A)(p) (ℝ(n)) with p ∈ (0,1] and are new even for its weighted variant. Finally, the authors characterize these spaces by anisotropic atomic decompositions. The authors also obtain the finite atomic decomposition characterization of H(A)(φ)(ℝ(n)), and, as an application, the authors prove that, for a given admissible triplet (φ, q, s), if T is a sublinear operator and maps all (φ, q, s)-atoms with q spaces ℬ, then T uniquely extends to a bounded sublinear operator from H(A)(φ)(ℝ(n)) to ℬ. These results are new even for anisotropic Orlicz-Hardy spaces on ℝ(n).

Pointwise Multipliers on Spaces of Homogeneous Type in the Sense of Coifman and Weiss

Directory of Open Access Journals (Sweden)

Yanchang Han

2014-01-01

homogeneous type in the sense of Coifman and Weiss, pointwise multipliers of inhomogeneous Besov and Triebel-Lizorkin spaces are obtained. We make no additional assumptions on the quasi-metric or the doubling measure. Hence, the results of this paper extend earlier related results to a more general setting.

Novel barium triel/tetrelides with the Pu3Pd5 structure type

International Nuclear Information System (INIS)

Duerr, Ines; Schwarz, Michael; Wendorff, Marco; Roehr, Caroline

2010-01-01

A series of ternary barium triel(M III )/tetrel(M IV )-ides Ba 3 M x III M 5-x IV (M III =Ga,In;M IV =Si,Ge,Sn;x=0-0.7) has been prepared from melts of the elements. They all crystallize with the Pu 3 Pd 5 type structure (orthorhombic, space group Cmcm) exhibiting isolated M 5 clusters of slightly distorted nido shape (square pyramids). For the silicides, where the binary border compound Ba 3 Si 5 does not exist, the Pu 3 Pd 5 type is stabilized by substituting 0.7 Si atoms per formula unit against Ga (Ba 3 Ga 0.7 Si 4.3 :a=1024.82(1),b=856.58(1),c=1024.18(1) pm, R1=0.0220) or by a very small substitution of In (Ba 3 In 0.1 Si 4.9 :a=1017.8(2),b=852.5(2),c=1020.1(3) pm, R1=0.0406). A comparable situation is found for the corresponding germanides, where 0.7 atoms of In (Ba 3 In 0.7 Ge 4.3 :a=1051.3(2),b=864.05(14),c=1054.7(3) pm, R1=0.0248) or Ga (Ba 3 Ga x Ge 5-x :a=1035.1(1),b=861.5(1),c=1036.8(1) pm, R1=0.0148) are necessary to stabilize a Ge-rich compound of this structure type. For the stannides, the situation is somewhat different, because the binary phase Ba 3 Sn 5 itself forms the Pu 3 Pd 5 type. In this case, the structure type remains stable up to a Ga content of 0.5 Ga/f.u. (Ba 3 Ga 0.5 Sn 4.5 :a=1100.41(14),b=896.19(11),c=1111.82(14) pm, R1=0.0169) and also with a substantial In content (Ba 3 In x Sn 5-x :x∼0.9(1);a=1110.5(2),b=900.0(2),c=1120.7(2) pm, R1=0.0262). As the five-atom nido cluster requires only 24 valence electrons per formula unit according to Zintl and Wade, an excess of electrons would be assumed for the binary tetrelides such as Ba 3 Sn 5 (26 v.e./f.u.) that even the maximal amount of triel substitution 0.7 M III /f.u. attained in the title compounds cannot sufficiently compensate for. An assessment of the geometric influence of varied valence electron counts however, coupled with a detailed analysis of the calculated electron densities and the partial densities of states in the energy region above the pseudo band gap at 24 v

In-situ investigations of structural changes during cyclic loading by high resolution reciprocal space mapping

DEFF Research Database (Denmark)

Diederichs, Annika M.; Thiel, Felix; Lienert, Ulrich

2017-01-01

dislocation structures can be identified using advanced electron microscopy and synchrotron techniques. A detailed characterization of the microstructure during cyclic loading by in-situ monitoring the internal structure within individual grains with high energy x-rays can help to understand and predict...... the materials behavior during cyclic deformation and to improve the material design. While monitoring macroscopic stress and strain during cyclic loading, reciprocal space maps of diffraction peaks from single grains are obtained with high resolution. High Resolution Reciprocal Space Mapping was applied...

Effect of space allowance and floor type on performance, welfare and physiological measurements of finishing beef heifers.

Science.gov (United States)

Keane, M P; McGee, M; O'Riordan, E G; Kelly, A K; Earley, B

2017-12-01

Accommodating cattle indoors during the winter is widely practiced throughout Europe. There is currently no legislation surrounding the space allowance and floor type that should be provided to cattle during this time, however, concerns have been raised regarding the type of housing systems currently in use. The objective of the study was to investigate the effect of space allowance and floor type on performance and welfare of finishing beef heifers. Continental crossbred heifers (n=240: mean initial live; weight, 504 (SD 35.8) kg) were blocked by breed, weight and age and randomly assigned to one of four treatments; (i) 3.0 m2, (ii) 4.5 m2 and (iii) 6.0 m2 space allowance per animal on a fully slatted concrete floor and (iv) 6.0 m2 space allowance per animal on a straw-bedded floor, for 105 days. Heifers were offered a total mixed ration ad libitum. Dry matter intake was recorded on a pen basis and refusals were weighed back twice weekly. Heifers were weighed, dirt scored and blood sampled every 3 weeks. Whole blood was analysed for complete cell counts and serum samples were assayed for metabolite concentrations. Behaviour was recorded continuously using IR cameras from days 70 to 87. Heifers' hooves were inspected for lesions at the start of the study and again after slaughter. Post-slaughter, carcass weight, conformation and fat scores and hide weight were recorded. Heifers housed at 4.5 m2 had a greater average daily live weight gain (ADG) than those on both of the other concrete slat treatments; however, space allowance had no effect on carcass weight. Heifers accommodated on straw had a greater ADG (0.15 kg) (PSpace allowance and floor type had no effect on the number of hoof lesions gained or on any of the haematological or metabolic variables measured. It was concluded that increasing space allowance above 3.0 m2/animal on concrete slats was of no benefit to animal performance but it did improve animal cleanliness. Housing heifers on straw instead of

Jubilite: A 4-,8-connected Cubic Structural Pattern in Space Group Pm3

Directory of Open Access Journals (Sweden)

Eduardo A. Castro

2005-05-01

Full Text Available Abstract: In the course of investigating structural modifications of the 3-,4-connected net known as the Pt3O4 structure-type (waserite, a novel 4-,8-connected structure-type was discovered. This lattice is generated by replacing the 3-connected trigonal planar vertices of the Pt3O4 structure-type with 4-connected tetrahedral vertices, to achieve a structure which possesses a generic empirical formula of JK6L8. In such a topological modification, the four 3-fold axes of the parent cubic, Pm3n, Pt3O4 structure-type are retained. Thus the 4-connected tetrahedral vertices are oriented so as to preserve cubic symmetry in the resulting Pm3, JK6L8 (jubilite lattice. The unit cell contains a single 8-connected cubecentered vertex, six 4-connected distorted square planar vertices and eight 4-connected distorted tetrahedral vertices. It is a Wellsean structure with a Wells point symbol given by (4166484(42826(43838 and a Schläfli symbol of (53/4, 4.2667. This latter index reveals a decrease in the lattice’s polygonality and concomitant increase in the connectivity through the transformation from waserite to jubilite. The topology of the parent waserite lattice (Pt3O4 corresponds to that of the Catalan structures with the Wells point symbol (843(834, which has the Schläfli symbol (8, 3.4285. Finally, it can be seen that a sequence of structure-types starting with waserite (Pt3O4 and moving to jubilite (JK6L8 and finally to fluorite (CaF2 represents a continuous crystallographic structural transformation in which the symmetry and topology undergo concomitant changes from one structure-type (waserite to the other structure-types. The topology of the fluorite lattice, represented by the Wells point symbol (424(462, and the Schläfli symbol (4, 51/3, indicates a discontinuous topological transformation from the intermediate jubilite lattice; like the discontinuous topological transformation from Pt3O4 to JK6L8; in which the

Pointwise convergence and Ascoli theorems for nearness spaces

Directory of Open Access Journals (Sweden)

Zhanbo Yang

2009-04-01

Full Text Available We first study subspaces and product spaces in the context of nearness spaces and prove that U-N spaces, C-N spaces, PN spaces and totally bounded nearness spaces are nearness hereditary; T-N spaces and compact nearness spaces are N-closed hereditary. We prove that N2 plus compact implies N-closed subsets. We prove that totally bounded, compact and N2 are productive. We generalize the concepts of neighborhood systems into the nearness spaces and prove that the nearness neighborhood systems are consistent with existing concepts of neighborhood systems in topological spaces, uniform spaces and proximity spaces respectively when considered in the respective sub-categories. We prove that a net of functions is convergent under the pointwise convergent nearness structure if and only if its cross-section at each point is convergent. We have also proved two Ascoli-Arzelà type of theorems.

Phase Space Dissimilarity Measures for Structural Health Monitoring

Energy Technology Data Exchange (ETDEWEB)

Bubacz, Jacob A [ORNL; Chmielewski, Hana T [ORNL; Pape, Alexander E [ORNL; Depersio, Andrew J [ORNL; Hively, Lee M [ORNL; Abercrombie, Robert K [ORNL; Boone, Shane [ORNL

2011-11-01

A novel method for structural health monitoring (SHM), known as the Phase Space Dissimilarity Measures (PSDM) approach, is proposed and developed. The patented PSDM approach has already been developed and demonstrated for a variety of equipment and biomedical applications. Here, we investigate SHM of bridges via analysis of time serial accelerometer measurements. This work has four aspects. The first is algorithm scalability, which was found to scale linearly from one processing core to four cores. Second, the same data are analyzed to determine how the use of the PSDM approach affects sensor placement. We found that a relatively low-density placement sufficiently captures the dynamics of the structure. Third, the same data are analyzed by unique combinations of accelerometer axes (vertical, longitudinal, and lateral with respect to the bridge) to determine how the choice of axes affects the analysis. The vertical axis is found to provide satisfactory SHM data. Fourth, statistical methods were investigated to validate the PSDM approach for this application, yielding statistically significant results.

First-principles real-space tight-binding LMTO calculation of electronic structures for atomic clusters

International Nuclear Information System (INIS)

Xie, Z.L.; Dy, K.S.; Wu, S.Y.

1997-01-01

A real-space scheme has been developed for a first-principles calculation of electronic structures and total energies of atomic clusters. The scheme is based on the combination of the tight-binding linear muffin-tin orbital (TBLMTO) method and the method of real-space Green close-quote s function. With this approach, the local electronic density of states can be conveniently determined from the real-space Green close-quote s function. Furthermore, the full electron density of a cluster can be directly calculated in real space. The scheme has been shown to be very efficient due to the incorporation of the method of real-space Green close-quote s function and Delley close-quote s method of evaluating multicenter integrals. copyright 1996 The American Physical Society

Realization of bicovariant differential calculus on the Lie algebra type noncommutative spaces

Science.gov (United States)

Meljanac, Stjepan; Krešić–Jurić, Saša; Martinić, Tea

2017-07-01

This paper investigates bicovariant differential calculus on noncommutative spaces of the Lie algebra type. For a given Lie algebra g0, we construct a Lie superalgebra g =g0⊕g1 containing noncommutative coordinates and one-forms. We show that g can be extended by a set of generators TAB whose action on the enveloping algebra U (g ) gives the commutation relations between monomials in U (g0 ) and one-forms. Realizations of noncommutative coordinates, one-forms, and the generators TAB as formal power series in a semicompleted Weyl superalgebra are found. In the special case dim(g0 ) =dim(g1 ) , we also find a realization of the exterior derivative on U (g0 ) . The realizations of these geometric objects yield a bicovariant differential calculus on U (g0 ) as a deformation of the standard calculus on the Euclidean space.

Space proliferation versus space-type dissemination: from semantic issues to political issues

International Nuclear Information System (INIS)

Gaillard-Sborowsky, Florence

2015-01-01

The space and ballistic capabilities relationships are regularly revisited in forums on international security, in particular about Iran and North Korea cases. The term 'space proliferation' is commonly used by analogy with nuclear proliferation. However, is this analogy relevant? Beyond the semantic aspects, this shift raises political issues that this paper will consider. The study of the assumptions regarding the analysis of nuclear and missile proliferation and their space counterparts will highlight some approximations and presuppositions, such as the amalgam between sounding rockets, launchers and missiles technologies, in order to suggest new thinking of these sensitive issues. (author)

Parabolic section and distance excess of space curves applied to protein structure classification

DEFF Research Database (Denmark)

Røgen, Peter; Karlsson, Per W.

2008-01-01

Proteins are long chain molecules that fold up into beautiful and complicated three-dimensional structures before fulfilling their biological functions in the living organisms. With the aim of providing an efficient tool for describing the proteins' native folds, we present a global geometric mea...... measure of a space curve. This geometric measure allows us to define descriptors of protein structures that quantify how parallel the secondary structure elements of a protein are. These descriptors are C-2 in deformations of the protein structure, are evaluated very fast and reliably...

Some common random fixed point theorems for contractive type conditions in cone random metric spaces

Directory of Open Access Journals (Sweden)

Saluja Gurucharan S.

2016-08-01

Full Text Available In this paper, we establish some common random fixed point theorems for contractive type conditions in the setting of cone random metric spaces. Our results unify, extend and generalize many known results from the current existing literature.

High-pressure U3O8 with the fluorite-type structure

International Nuclear Information System (INIS)

Zhang, F.X.; Lang, M.; Wang, J.W.; Li, W.X.; Sun, K.; Prakapenka, V.; Ewing, R.C.

2014-01-01

A new high-pressure phase of U 3 O 8 , which has a fluorite-type structure, forms at pressures greater than ∼8.1 GPa that was confirmed by in situ x-ray diffraction (XRD) measurements. The fluorite-type U 3 O 8 is stable at pressures at least up to ∼40 GPa and temperatures to 1700 K, and quenchable to ambient conditions. Based on the XRD analysis, there is a huge volume collapse (>20%) for U 3 O 8 during the phase transition and the quenched high-pressure phase is 28% denser than the initial orthorhombic phase at ambient conditions. The high-pressure phase has a very low compressibility comparing with the starting orthorhombic phase. - Graphical abstract: α-U 3 O 8 is in a layered structure with orthorhombic symmetry, at high pressures, it transformed to a fluorite-type cubic structure. There are a lot of defects in the cubic structure, and it is a new kind of hyperstoichiometric uranium oxide, which is stable at ambient conditions. - Highlights: • A new fluorite-type high-pressure phase was found in hyperstoichometric UO 2 +x (x∼0.8). • The new high-pressure structure is quenchable to ambient conditions. • Pressure driven phase transition in orthorhombic U 3 O 8 was first found

Design and implementation of robust decentralized control laws for the ACES structure at Marshall Space Flight Center

Science.gov (United States)

Collins, Emmanuel G., Jr.; Phillips, Douglas; Hyland, David C.

1990-01-01

An experiment was conducted to design controllers that would provide substantial reduction of line-of-sight control errors. The satisfaction of this objective required the controllers to attenuate the beam vibration significantly. Particular emphasis was placed on controller simplicity (i.e., reduced-order and decentralized controller architectures). Complexity reduction in control law implementation is of paramount interest due to stringent limitations on throughput of even state-of-the-art space qualified processors. The results of this experiment successfully demonstrate active vibrator control for a flexible structure. The testbed is the ACES structure at the NASA Marshall Space Flight Center. The ACES structure is dynamically traceable to future space systems and especially allows the study of line-of-sight control issues.

Topology Optimization and Robotic Fabrication of Advanced Timber Space-frame Structures

DEFF Research Database (Denmark)

Søndergaard, Asbjørn; Amir, Oded; Eversmann, Phillip

2016-01-01

This paper presents a novel method for integrated topology optimization and fabrication of advanced timber space-frame structures. The method, developed in research collaboration between ETH Zürich, Aarhus School of Architecture and Israel Institute of Technology, entails the coupling of truss...... processes solving timber joint intersections, robotically controlling member prefabrication, and spatial robotic assembly of the optimized timber structures. The implication of this concept is studied through pilot fabrication and load-testing of a full scale prototype structure.......-based topology optimization with digital procedures for rationalization and robotic assembly of bespoke timber members, through a procedural, cross-application workflow. Through this, a direct chaining of optimization and robotic fabrication is established, in which optimization data is driving subsequent...

An Investigation of Interplanetary Structures for Solar Cycles 23 and 24 and their Space Weather Consequences.

Science.gov (United States)

Sultan, M. S.; Jules, A.; Marchese, P.; Damas, M. C.

2017-12-01

It is crucial to study space weather because severe interplanetary conditions can cause geomagnetic storms that may damage both space- and ground-based technological systems such as satellites, communication systems, and power grids. Interplanetary coronal mass ejections (ICMEs) and corotating interaction regions (CIRs) are the primary drivers of geomagnetic storms. As they travel through interplanetary space and reach geospace, their spatial structures change which can result in various geomagnetic effects. Therefore, studying these drivers and their structures is essential in order to better understand and mitigate their impact on technological systems, as well as to forecast geomagnetic storms. In this study, over 150 storms were cross-checked for both solar cycles (SC) 23 and 24. This data has revealed the most common interplanetary structures, i.e., sheath (Sh); magnetic cloud following a shock front (sMC); sheath region and magnetic cloud (Sh/MC); and corotating interaction regions (CIRs). Furthermore, plasma parameters as well as variation in the intensity and duration of storms resulting from different interplanetary structures are studied for their effect on geomagnetically induced currents (GICs), as well as for their effect on power grids. Although preliminary results for SC 23 indicate that storm intensity may play a dominant role for GICs, duration might also be a factor, albeit smaller. Results from both SC 23 and 24 are analyzed and compared, and should lead to an enhanced understanding of space weather consequences of interplanetary structures and their possible forecasting.

Solving Component Structural Dynamic Failures Due to Extremely High Frequency Structural Response on the Space Shuttle Program

Science.gov (United States)

Frady, Greg; Nesman, Thomas; Zoladz, Thomas; Szabo, Roland

2010-01-01

For many years, the capabilities to determine the root-cause failure of component failures have been limited to the analytical tools and the state of the art data acquisition systems. With this limited capability, many anomalies have been resolved by adding material to the design to increase robustness without the ability to determine if the design solution was satisfactory until after a series of expensive test programs were complete. The risk of failure and multiple design, test, and redesign cycles were high. During the Space Shuttle Program, many crack investigations in high energy density turbomachines, like the SSME turbopumps and high energy flows in the main propulsion system, have led to the discovery of numerous root-cause failures and anomalies due to the coexistences of acoustic forcing functions, structural natural modes, and a high energy excitation, such as an edge tone or shedding flow, leading the technical community to understand many of the primary contributors to extremely high frequency high cycle fatique fluid-structure interaction anomalies. These contributors have been identified using advanced analysis tools and verified using component and system tests during component ground tests, systems tests, and flight. The structural dynamics and fluid dynamics communities have developed a special sensitivity to the fluid-structure interaction problems and have been able to adjust and solve these problems in a time effective manner to meet budget and schedule deadlines of operational vehicle programs, such as the Space Shuttle Program over the years.

Changes in the internal structure of the human crystalline lens with diabetes mellitus type 1 and type 2

NARCIS (Netherlands)

Wiemer, N.G.M.; Dubbelman, M.; Hermans, E.A.; Ringens, P.J.; Polak, B.C.P.

2008-01-01

Purpose: To investigate the effect of diabetes mellitus (DM) type 1 and type 2 on the internal structure of the lens. Design: Observational cross-sectional study. Participants and Controls: One hundred seven patients with DM type 1, 106 patients with DM type 2, and 75 healthy control subjects.

Perception of open urban space – Bevk square in Nova Gorica

Directory of Open Access Journals (Sweden)

Nataša Bratina

1997-01-01

Full Text Available In research on perception of open urban space, psychological and structural aspects are important, as well as social use. Social use however is most important, because open urban space and its green surfaces satisfies needs of an urban population. The psychological aspect applies to direct experiencing and perception of space, while the structural aspect proves that public urban places are an important category in the urban structure. On the example of Bevk square, Nova Gorica, three types of analyses were carried out. With the structural analysis and evaluation, development and structure of the place were shown, its problems and qualities. The survey on public opinion utilised the method of cognitive mapping, enabled definition of the image of the square, as perceived by everyday users. With the method of time samples events on the square were observed, in different time slots and days of the week.

Recent advance on design and manufacturing of composite anisogrid structures for space launchers

Science.gov (United States)

Totaro, G.; De Nicola, F.

2012-12-01

Anisogrid composite shells have been developed and applied since the eighties by the Russian technology aiming at critical weight structures for space launchers, as interstages and cone adapters. The manufacturing process commonly applied is based on the wet filament winding. The paper concerns with some developments of design and manufacturing recently performed at the Italian Aerospace Research Center on a cylindrical structural model representative of this kind of structures. The framework of preliminary design is improved by introducing the concept of suboptimal configuration in order to match the stiffness requirement of the shell and minimise the mass, in conjunction with the typical strength constraints. The undertaken manufacturing process is based on dry robotic winding for the lattice structure and for the outer skin, with the aid of usual rubber tooling and new devices for the automated deposition strategy. Resin infusion under vacuum bag and co-cure of the system of ribs and skin is finally applied out-of-autoclave, with the aid of a heated mandrel. With such approach an interstage structural model (scale factor 1:1.5) has been designed, manufactured and tested. Design requirements and loads refer to a typical space launcher whose baseline configuration is made in aluminium. The global mechanical test of the manufactured structure has confirmed the expected high structural performance. The possibility to reach substantial weight savings in comparison with the aluminium benchmark has been fully demonstrated.

Evaluation of linear DC motor actuators for control of large space structures

OpenAIRE

Ide, Eric Nelson

1988-01-01

This thesis examines the use of a linear DC motor as a proof mass actuator for the control of large space structures. A model for the actuator, including the current and force compensation used, is derived. Because of the force compensation, the actuator is unstable when placed on a structure. Relative position feedback is used for actuator stabilization. This method of compensation couples the actuator to the mast in a feedback configuration. Three compensator designs are prop...

How to defeat Wüthrich's abysmal embarrassment argument against space-time structuralism

NARCIS (Netherlands)

F.A. Muller (Archibald)

2011-01-01

textabstractIn his award-winning contribution to the biannual PSA conference at Pittsburgh in 2008, Christian Wüthrich mounted an argument against structuralism about spacetime in the context of the general theory of relativity (GTR), to the effect that structuralists cannot discern space-time

Co-linear spin configurations in corundum-type structures

International Nuclear Information System (INIS)

Bertaut, F.

1961-01-01

The colinear magnetic configurations possible in corundum-type structures (α-Fe 2 O 3 ; Cr 2 O 3 ) are solutions of a matrices problem. Their regions of stability are bounded by inequality relationships between exchange integrals. (author) [fr

A Study of Flexible Composites for Expandable Space Structures

Science.gov (United States)

Scotti, Stephen J.

2016-01-01

Payload volume for launch vehicles is a critical constraint that impacts spacecraft design. Deployment mechanisms, such as those used for solar arrays and antennas, are approaches that have successfully accommodated this constraint, however, providing pressurized volumes that can be packaged compactly at launch and expanded in space is still a challenge. One approach that has been under development for many years is to utilize softgoods - woven fabric for straps, cloth, and with appropriate coatings, bladders - to provide this expandable pressure vessel capability. The mechanics of woven structure is complicated by a response that is nonlinear and often nonrepeatable due to the discrete nature of the woven fiber architecture. This complexity reduces engineering confidence to reliably design and certify these structures, which increases costs due to increased requirements for system testing. The present study explores flexible composite materials systems as an alternative to the heritage softgoods approach. Materials were obtained from vendors who utilize flexible composites for non-aerospace products to determine some initial physical and mechanical properties of the materials. Uniaxial mechanical testing was performed to obtain the stress-strain response of the flexible composites and the failure behavior. A failure criterion was developed from the data, and a space habitat application was used to provide an estimate of the relative performance of flexible composites compared to the heritage softgoods approach. Initial results are promising with a 25% mass savings estimated for the flexible composite solution.

Vacancy-type defects in Al2O3/GaN structure probed by monoenergetic positron beams

Science.gov (United States)

Uedono, Akira; Nabatame, Toshihide; Egger, Werner; Koschine, Tönjes; Hugenschmidt, Christoph; Dickmann, Marcel; Sumiya, Masatomo; Ishibashi, Shoji

2018-04-01

Defects in the Al2O3(25 nm)/GaN structure were probed by using monoenergetic positron beams. Al2O3 films were deposited on GaN by atomic layer deposition at 300 °C. Temperature treatment above 800 °C leads to the introduction of vacancy-type defects in GaN due to outdiffusion of atoms from GaN into Al2O3. The width of the damaged region was determined to be 40-50 nm from the Al2O3/GaN interface, and some of the vacancies were identified to act as electron trapping centers. In the Al2O3 film before and after annealing treatment at 300-900 °C, open spaces with three different sizes were found to coexist. The density of medium-sized open spaces started to decrease above 800 °C, which was associated with the interaction between GaN and Al2O3. Effects of the electron trapping/detrapping processes of interface states on the flat band voltage and the defects in GaN were also discussed.

Soil structure interactions of eastern U.S. type earthquakes

International Nuclear Information System (INIS)

Chang Chen; Serhan, S.

1991-01-01

Two types of earthquakes have occurred in the eastern US in the past. One of them was the infrequent major events such as the 1811-1812 New Madrid Earthquakes, or the 1886 Charleston Earthquake. The other type was the frequent shallow earthquakes with high frequency, short duration and high accelerations. Two eastern US nuclear power plants, V.C Summer and Perry, went through extensive licensing effort to obtain fuel load licenses after this type of earthquake was recorded on sites and exceeded the design bases beyond 10 hertz region. This paper discusses the soil-structure interactions of the latter type of earthquakes

Curved twistor spaces and H-space

International Nuclear Information System (INIS)

Tod, K.P.

1980-01-01

The curved twistor space construction of Penrose for anti-self-dual solutions to the Einstein vacuum equations is described. Curved twistor spaces are defined and it is shown with the aid of an example how to obtain them by deforming the complex structure of regions of flat twistor space. The connection of this procedure with Newman's H-space construction via asymptotic twistor space is outlined. (Auth.)

Type III radio bursts in a flaming structure

International Nuclear Information System (INIS)

Karlicky, M.; Tlamicha, A.

1977-01-01

An interpretation is presented of the burst of 3.7.1974. The slowly drifting, fine structure in this type III burst is evidence of the existence of very fast, spatially extensive processes in the corona. The concept is presented of a rapidly varying, magnetohydrodynamically unstable, flaming structure of the magnetic field and, using this model, the intensities were computed of the magnetic field at certain altitudes and at two moments differing by 1.4 s. (author)

Concept-Development of a Structure Supported Membrane for Deployable Space Applications - From Nature to Manufacture and Testing

Science.gov (United States)

Zander, Martin; Belvin, W. K.

2012-01-01

Current space applications of membrane structures include large area solar power arrays, solar sails, antennas, and numerous other large aperture devices like the solar shades of the new James Webb Space Telescope. These expandable structural systems, deployed in-orbit to achieve the desired geometry, are used to collect, reflect and/or transmit electromagnetic radiation. This work, a feasibility study supporting a diploma thesis, describes the systematic process for developing a biologically inspired concept for a structure supported (integrated) membrane, that features a rip stop principle, makes self-deployment possible and is part of an ultra-light weight space application. Novel manufacturing of membrane prototypes and test results are presented for the rip-stop concepts. Test data showed that the new membrane concept has a higher tear resistance than neat film of equivalent mass.

A Low-Order Harmonic Elimination Scheme for Induction Motor Drives Using a Multilevel Octadecagonal Space Vector Structure With a Single DC Source

DEFF Research Database (Denmark)

Boby, Mathews; Rahul, Arun; Gopakumar, K.

2018-01-01

Conventional voltage-source inverters used for induction motor drives generate a hexagonal space vector structure. In the overmodulation range, the hexagonal space vector structure generates low-order harmonics in the phase voltage resulting in low-order torque ripple in the motor. Inverter...... topologies with an octadecagonal (18 sided) space vector structure eliminate fifth-, seventh-, eleventh-, and thirteenth-order harmonics from the phase voltage, and hence, the dominant sixth- and twelfth-order torque ripple generation is eliminated. Octadecagonal space vector structures proposed in the past...... require multiple dc sources, which makes four-quadrant operation of the drive system difficult and costly. In this paper, the formation of a multilevel nine-concentric octadecagonal space vector structure using a single dc source is proposed. Detailed experimental results, using open-loop V/f control...

Intelligent Flexible Materials for Space Structures: Expandable Habitat Engineering Development Unit

Science.gov (United States)

Hinkle, Jon; Sharpe, George; Lin, John; Wiley, Cliff; Timmers, Richard

2010-01-01

Expandable habitable elements are an enabling technology for human exploration in space and on planetary surfaces. Large geometries can be deployed from a small launch volume, allowing greater mission capability while reducing mass and improving robustness over traditional rigid shells. This report describes research performed by ILC Dover under the Intelligent Flexible Materials for Space Structures program on the design and manufacture of softgoods for LaRC's Expandable Habitat Engineering Development Unit (EDU). The EDU is a full-scale structural test article of an expandable hybrid habitat, integrating an expandable softgoods center section with two rigid end caps. The design of the bladder, restraint layer and a mock-up Thermal Micrometeoroid Cover is detailed together with the design of the interface hardware used to attach them to the end caps. The integration and design of two windows and a floor are also covered. Analysis was performed to study the effects of the open weave design, and to determine the correct webbing and fabric configuration. Stress analyses were also carried out on the interfaces between the softgoods and the end caps and windows. Testing experimentally determined the strength of the fabric and straps, and component testing was used to proof several critical parts of the design. This program established new manufacturing and design techniques that can be applied to future applications in expandable structures.

A Good $\\lambda$ Estimate for Multilinear Commutator of Singular Integral on Spaces of Homogeneous Type

Directory of Open Access Journals (Sweden)

Zhang Qian

2011-04-01

Full Text Available In this paper, a good $\\lambda$ estimate for the multilinear commutator associated to the singular integral operator on the spaces of homogeneous type is obtained. Under this result, we get the$(L^p(X,L^q(X$-boundedness of the multilinear commutator.

Statistical mechanics of free particles on space with Lie-type noncommutativity

Energy Technology Data Exchange (ETDEWEB)

Shariati, Ahmad; Khorrami, Mohammad; Fatollahi, Amir H, E-mail: shariati@mailaps.or, E-mail: mamwad@mailaps.or, E-mail: ahfatol@gmail.co [Department of Physics, Alzahra University, Tehran 1993891167 (Iran, Islamic Republic of)

2010-07-16

Effects of Lie-type noncommutativity on thermodynamic properties of a system of free identical particles are investigated. A definition for finite volume of the configuration space is given, and the grandcanonical partition function in the thermodynamic limit is calculated. Two possible definitions for the pressure are discussed, which are equivalent when the noncommutativity vanishes. The thermodynamic observables are extracted from the partition function. Different limits are discussed where either the noncommutativity or the quantum effects are important. Finally, specific cases are discussed where the group is SU(2) or SO(3), and the partition function of a nondegenerate gas is calculated.

Structural Verification of the First Orbital Wonder of the World - The Structural Testing and Analysis of the International Space Station (ISS)

Science.gov (United States)

Zipay, John J.; Bernstein, Karen S.; Bruno, Erica E.; Deloo, Phillipe; Patin, Raymond

2012-01-01

The International Space Station (ISS) can be considered one of the structural engineering wonders of the world. On par with the World Trade Center, the Colossus of Rhodes, the Statue of Liberty, the Great Pyramids, the Petronas towers and the Burj Khalifa skyscraper of Dubai, the ambition and scope of the ISS structural design, verification and assembly effort is a truly global success story. With its on-orbit life projected to be from its beginning in 1998 to the year 2020 (and perhaps beyond), all of those who participated in its development can consider themselves part of an historic engineering achievement representing all of humanity. The structural design and verification of the ISS could be the subject of many scholarly papers. Several papers have been written on the structural dynamic characterization of the ISS once it was assembled on-orbit [1], but the ground-based activities required to assure structural integrity and structural life of the individual elements from delivery to orbit through assembly and planned on-orbit operations have never been totally summarized. This paper is intended to give the reader an overview of some of the key decisions made during the structural verification planning for the elements of the U.S. On-Orbit Segment (USOS) as well as to summarize the many structural tests and structural analyses that were performed on its major elements. An effort is made for this paper to be summarily comprehensive, but as with all knowledge capture efforts of this kind, there are bound to be errors of omission. Should the reader discover any of these, please feel free to contact the principal author. The ISS (Figure 1) is composed of pre-integrated truss segments and pressurized elements supplied by NASA, the Russian Federal Space Agency (RSA), the European Space Agency (ESA) and the Japanese Aerospace Exploration Agency (JAXA). Each of these elements was delivered to orbit by a launch vehicle and connected to one another either robotically or

On the analytical modeling of the nonlinear vibrations of pretensioned space structures

Science.gov (United States)

Housner, J. M.; Belvin, W. K.

1983-01-01

Pretensioned structures are receiving considerable attention as candidate large space structures. A typical example is a hoop-column antenna. The large number of preloaded members requires efficient analytical methods for concept validation and design. Validation through analyses is especially important since ground testing may be limited due to gravity effects and structural size. The present investigation has the objective to present an examination of the analytical modeling of pretensioned members undergoing nonlinear vibrations. Two approximate nonlinear analysis are developed to model general structural arrangements which include beam-columns and pretensioned cables attached to a common nucleus, such as may occur at a joint of a pretensioned structure. Attention is given to structures undergoing nonlinear steady-state oscillations due to sinusoidal excitation forces. Three analyses, linear, quasi-linear, and nonlinear are conducted and applied to study the response of a relatively simple cable stiffened structure.

System Identification of Civil Engineering Structures using State Space and ARMAV Models

DEFF Research Database (Denmark)

Andersen, P.; Kirkegaard, Poul Henning; Brincker, Rune

In this paper the relations between an ambient excited structural system, represented by an innovation state space system, and the Auto-Regressive Moving Average Vector (ARMAV) model are considered. It is shown how to obtain a multivariate estimate of the ARMAV model from output measurements, usi...

Crystal structure of clathrates of Hofmann dma-type

International Nuclear Information System (INIS)

NIshikiori, Sh.; Ivamoto, T.

1999-01-01

Seven new clathrates Cd(DMA) 2 Ni(CN) 4 ·xG (x=1, G=aniline, 2,3-xylidine, 2,4-xylidine, 2,5-xylidine, 2,6-xylidine, 3,5-xylidine, and x=2, G=2,4,6-trimethylaniline) of Hofmann type are synthesized by amine substitution for dimethylamine (DMA). On the base of x-ray diffraction data it is shown that geometry of guest molecule in cage-like hollow determines the structure of the host and crystal structure of clathrates. Two-dimension metallocomplex of the host of studied clathrates is characterized by elastic folded structure appearing as a result of angular deformation of bond between Cd atoms and host cyanide bridge. Guest molecule orientation is fixed by hydrogen bond. Structural elasticity of the host complex directs to differences in crystal structure of clathrates formed and to considerable variety of incorporated guests [ru

Factors controlling crystallization of miserite glass-ceramic.

Science.gov (United States)

Muhammed, Fenik K; Moorehead, Robert; van Noort, Richard; Pollington, Sarah

2015-12-01

The purpose of this study was to investigate a range of variables affecting the synthesis of a miserite glass-ceramic (GC). Miserite glass was synthesized by the melt quench technique. The crystallization kinetics of the glass were determined using Differential Thermal Analysis (DTA). The glasses were ground with dry ball-milling and then sieved to different particle sizes prior to sintering. These particle sizes were submitted to heat treatment regimes in a high temperature furnace to form the GC. The crystal phases of the GC were analyzed by X-ray diffraction (XRD). Scanning electron microscopy (SEM) was used to examine the microstructure of the cerammed glass. XRD analysis confirmed that the predominant crystalline phase of the GC was miserite along with a minor crystalline phase of cristobalite only when the particle size is <20 μm and the heat treatment at 1000°C was carried out for 4h and slowly cooled at the furnace rate. For larger particle sizes and faster cooling rates, a pseudowollastonite crystalline phase was produced. Short sintering times produced either a pseudowollastonite or xonotolite crystalline phase. The current study has shown that particle size and heat treatment schedules are major factors in controlling the synthesis of miserite GC. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Structures and Corresponding Functions of Five Types of Picornaviral 2A Proteins

Directory of Open Access Journals (Sweden)

Xiaoyao Yang

2017-07-01

Full Text Available Among the few non-structural proteins encoded by the picornaviral genome, the 2A protein is particularly special, irrespective of structure or function. During the evolution of the Picornaviridae family, the 2A protein has been highly non-conserved. We believe that the 2A protein in this family can be classified into at least five distinct types according to previous studies. These five types are (A chymotrypsin-like 2A, (B Parechovirus-like 2A, (C hepatitis-A-virus-like 2A, (D Aphthovirus-like 2A, and (E 2A sequence of the genus Cardiovirus. We carried out a phylogenetic analysis and found that there was almost no homology between each type. Subsequently, we aligned the sequences within each type and found that the functional motifs in each type are highly conserved. These different motifs perform different functions. Therefore, in this review, we introduce the structures and functions of these five types of 2As separately. Based on the structures and functions, we provide suggestions to combat picornaviruses. The complexity and diversity of the 2A protein has caused great difficulties in functional and antiviral research. In this review, researchers can find useful information on the 2A protein and thus conduct improved antiviral research.

Direction dependent structures in general relativity

International Nuclear Information System (INIS)

Herberthson, M.

1993-01-01

This thesis deals with, within the theory of general relativity, asymptotic properties of certain types of space-times. Using conformal transformations, it is possible to describe asymptotic properties of a physical space-time in terms of the local behaviour of the new, rescaled space-time. One then uses so called direction dependent structures. We present two such structures and applications to them. One structure is used in the study of spacelike (or spatial) infinity. We discuss the asymptotic conditions on the gravitational and the electromagnetic field, especially the conditions put on directions corresponding to future and past null infinity. It is shown that these fields have desired physical properties. The other structure is used in connection with timelike infinity. Using this structure, we suggest a new definition of timelike infinity. This definition differs significantly from earlier definitions, and leads to the concept of asymptotically stationary space-times. We also suggest a definition of asymptotic flatness at future null infinity, and a definition of a black hole which is, in a sense, local. Both of these definitions fit nicely into the structure. (24 refs.)

Some s-numbers of an integral operator of Hardy type in Banach function spaces

Czech Academy of Sciences Publication Activity Database

Edmunds, D.; Gogatishvili, Amiran; Kopaliani, T.; Samashvili, N.

2016-01-01

Roč. 207, July (2016), s. 76-97 ISSN 0021-9045 R&D Projects: GA ČR GA13-14743S Institutional support: RVO:67985840 Keywords : Hardy type operators * Banach function spaces * s- numbers * compact linear operators Subject RIV: BA - General Mathematics Impact factor: 0.931, year: 2016 http://www.sciencedirect.com/science/article/pii/S0021904516000265

Structural Series in the Ternary A-Mn-As System (A = Alkali Metal): Double-Layer-Type CsMn4As3 and RbMn4As3 and Tunnel-Type KMn4As3.

Science.gov (United States)

Ishida, Junichi; Iimura, Soshi; Hosono, Hideo

2018-04-16

New manganese arsenides CsMn 4 As 3 , RbMn 4 As 3 , and KMn 4 As 3 were synthesized by solid-state reaction. They consist of edge-sharing MnAs 4 tetrahedra, which are a building block similar to those of Fe-based superconductors. CsMn 4 As 3 and RbMn 4 As 3 adopt the KCu 4 S 3 -type structure (tetragonal P4/ mmm space group, No. 123) with a Mn 4 As 3 double layer, while KMn 4 As 3 has the CaFe 4 As 3 -type structure (orthorhombic Pnma space group, No. 62) with a Mn 4 As 3 tunnel framework. The structural change from CsMn 4 As 3 and RbMn 4 As 3 to KMn 4 As 3 as well as the structural trend of the other ternary A-Mn-As (A = alkali metal) and AE-Mn-As (AE = alkaline-earth metal) compounds is understood as a consequence of reduction of the coordination number around the A and AE sites owing to the decrease of the ionic radius from Cs + to Mg 2+ . Electrical resistivity measurements confirm that the three new phases are Mott insulators with band gaps of 0.52 (CsMn 4 As 3 ), 0.43 (RbMn 4 As 3 ), and 0.31 eV (KMn 4 As 3 ). Magnetic and heat capacity measurements revealed that CsMn 4 As 3 and RbMn 4 As 3 are antiferromagnets without apparent phase transitions below 400 K, which is similar to the magnetism of LaMnAsO and BaMn 2 As 2 , while the existence of the ferromagnetic component was indicated in KMn 4 As 3 with a magnetic transition at 179 K.

Topological structure of the space of phenotypes: the case of RNA neutral networks.

Directory of Open Access Journals (Sweden)

Jacobo Aguirre

Full Text Available The evolution and adaptation of molecular populations is constrained by the diversity accessible through mutational processes. RNA is a paradigmatic example of biopolymer where genotype (sequence and phenotype (approximated by the secondary structure fold are identified in a single molecule. The extreme redundancy of the genotype-phenotype map leads to large ensembles of RNA sequences that fold into the same secondary structure and can be connected through single-point mutations. These ensembles define neutral networks of phenotypes in sequence space. Here we analyze the topological properties of neutral networks formed by 12-nucleotides RNA sequences, obtained through the exhaustive folding of sequence space. A total of 4(12 sequences fragments into 645 subnetworks that correspond to 57 different secondary structures. The topological analysis reveals that each subnetwork is far from being random: it has a degree distribution with a well-defined average and a small dispersion, a high clustering coefficient, and an average shortest path between nodes close to its minimum possible value, i.e. the Hamming distance between sequences. RNA neutral networks are assortative due to the correlation in the composition of neighboring sequences, a feature that together with the symmetries inherent to the folding process explains the existence of communities. Several topological relationships can be analytically derived attending to structural restrictions and generic properties of the folding process. The average degree of these phenotypic networks grows logarithmically with their size, such that abundant phenotypes have the additional advantage of being more robust to mutations. This property prevents fragmentation of neutral networks and thus enhances the navigability of sequence space. In summary, RNA neutral networks show unique topological properties, unknown to other networks previously described.

Priorities in national space strategies and governance of the member states of the European Space Agency

Science.gov (United States)

Adriaensen, Maarten; Giannopapa, Christina; Sagath, Daniel; Papastefanou, Anastasia

2015-12-01

, international cooperation, and European non-dependence. The second part of the paper provides a categorisation of national space governance structures in ESA Member States. Different governance models are identified depending on the responsible ministries for space for a number of space related organisations and ESA. In the case of ESA, these can typically vary from the more traditional ministry of science and/or education, the ministry of industry and/or innovation to the more recent ones being the ministry of economy and the ministry of transport. Recognising the transverse nature of space and its potential as a tool for a number of policies like agriculture, environment, maritime, disaster management, etc., other ministries are more and more getting involved in space activities. The development and implementation of the space strategy and policy of a Member State is realised though the engagement of an implementing entity. The type, role and activity vary from Member State to Member State.

Milestones Towards Hot CMC Structures for Operational Space Rentry Vehicles

Science.gov (United States)

Hald, H.; Weihs, H.; Reimer, T.

2002-01-01

Hot structures made of ceramic matrix composites (CMC) for space reentry vehicles play a key role regarding feasibility of advanced and reusable future space transportation systems. Thus realization of applicable flight hardware concerning hot primary structures like a nose cap or body flaps and thermal protection systems (TPS) requires system competence w.r.t. sophisticated know how in material processing, manufacturing and qualification of structural components and in all aspects from process control, use of NDI techniques, arc jet testing, hot structure testing to flight concept validation. This goal has been achieved so far by DLR while following a dedicated development road map since more than a decade culminating at present in the supply of the nose cap system for NASA's X-38; the flight hardware has been installed successfully in October 2001. A number of unique hardware development milestones had to be achieved in the past to finally reach this level of system competence. It is the intention of this paper to highlight the most important technical issues and achievements from the essential projects and developments to finally provide a comprehensive insight into DLR's past and future development road map w.r.t. CMC hot structures for space reentry vehicles. Based on DLR's C/C-SiC material which is produced with the inhouse developed liquid silicon infiltration process (LSI) the development strategy first concentrated on basic material properties evaluation in various arc jet testing facilities. As soon as a basic understanding of oxidation and erosion mechanisms had been achieved further efforts concentrated on inflight verification of both materials and design concepts for hot structures. Consequently coated and uncoated C/C-SiC specimens were integrated into the ablative heat shield of Russian FOTON capsules and they were tested during two missions in 1992 and 1994. Following on, a hot structure experiment called CETEX which principally was a kind of a

Evaluation of soil-structure interaction for structures subjected to earthquake loading with different types of foundation

Directory of Open Access Journals (Sweden)

Elwi Mohammed

2018-01-01

Full Text Available However though the structures are supported on soil, most of the designers do not consider the soil structure interaction and its subsequent effect on structure during an earthquake. Different soil properties can affect seismic waves as they pass through a soil layer. When a structure is subjected to an earthquake excitation, it interacts the foundation and soil, and thus changes the motion of the ground. It means that the movement of the whole ground structure system is influenced by type of soil as well as by the type of structure. Tall buildings are supposed to be of engineered construction in sense that they might have been analyzed and designed to meet the provision of relevant codes of practice and building bye-laws. IS 1893: 2002 “Criteria for Earthquake Resistant Design of Structures” gives response spectrum for different types of soil such as hard, medium and soft. An attempt has been made in this paper to study the effect of Soil-structure interaction on multi storeyed buildings with various foundation systems. Also to study the response of buildings subjected to seismic forces with Rigid and Flexible foundations. Multi storeyed buildings with fixed and flexible support subjected to seismic forces were analyzed under different soil conditions like hard, medium and soft. The buildings were analyzed by Response spectrum method using software SAP2000. The response of building frames such as Lateral deflection, Story drift, Base shear, Axial force and Column moment values for all building frames were presented in this paper.

Fluid Flow through Porous Sandstone with Overprinting and Intersecting Geological Structures of Various Types

Science.gov (United States)

Zhou, X.; Karimi-Fard, M.; Durlofsky, L.; Aydin, A.

2010-12-01

Impact of a wide variety of structural heterogeneities on fluid flow in an aeolian sandstone in the Valley of Fire State Park (NV), such as (1) dilatant fractures (joints), (2) shear fractures (faults), and (3) contraction/compaction structures (compaction bands), are considered. Each type of these structures has its own geometry, spacing, distribution, connectivity, and hydraulic properties, which either enhance or impede subsurface fluid flow. Permeability of these structures may, on average, be a few orders of magnitude higher or lower than those of the corresponding matrix rocks. In recent years, the influence of a single type of these heterogeneities on fluid flow has been studied individually, such as joints, compaction bands or faults. However, as different types of geological structures are commonly present together in the same rock volume, their combined effect requires a more detailed assessment. In this study, fluid flow simulations are performed using a special finite-volume discretization technique that was developed by Karimi-Fard et al. (2004; 2006). Using this approach, thin features such as fractures and compaction bands are represented as linear elements in unstructured 2D models and as planar elements in 3D models, which significantly reduces the total number of cells and simplifies grid generation. The cell geometric information and the cell-to-cell transmissibility obtained from this discretization technique are input to Stanford’s General Purpose Research Simulator (GPRS) for fluid flow simulation. To account for the effects of the various geological structures on subsurface flow, we perform permeability upscaling over regions corresponding to large-scale simulation grid blocks in order to obtain equivalent permeability components in two principal directions. We will focus on the following problems: (1) compaction bands of multisets; (2) compartmentalization of compaction bands of high-angle, low-angle and horizontal; (3) joints overprinting

Ce{sup 3+} incorporated structural and magnetic properties of M type barium hexaferrites

Energy Technology Data Exchange (ETDEWEB)

Pawar, R.A. [Department of Physics, Arts, Commerce and Science College, Satral, MS (India); Desai, S.S.; Tamboli, Q.Y. [Materials Research Laboratory, Shrikrishna Mahavidyalaya, Gunjoti 413613, MS (India); Shirsath, Sagar E. [Spin Device Technology Center, Faculty of Engineering, Shinshu University, Nagano 380-8553 (Japan); Patange, S.M., E-mail: smpatange@rediffmail.com [Materials Research Laboratory, Shrikrishna Mahavidyalaya, Gunjoti 413613, MS (India)

2015-03-15

M type barium hexaferrites BaCe{sub x}Fe{sub 12−x}O{sub 19} (0≤x≤0.3) (BCFO) were synthesized by the sol–gel auto combination method. Optimum annealing temperature of hexagonal phase was determined by using the TGA analysis. The annealing temperature form the TGA is 1000 °C samples annealed 1000 °C for 5 h to produce M type hexaferrites. X-ray diffraction data run to full Prof Program (Winploter 2010) pattern indicate that samples are single phase hexagonal structure with space group P6{sub 3}/mmc. Lattice parameter ‘a’ and ‘c’ increase with increase in Ce content x. Results of field emission scanning electron microscope show that the grains are regular hexagonal platelets with sizes from 0.3 to 1.4 μm. It is observed that from M–H curve value of the saturation magnetization and coercivity decreases with increasing x. Curie temperature from magnetization with temperature plot is found to decrease with Ce{sup 3+} substitution x due to decreases in magnetic interaction. - Highlights: • Ce{sup 3+} substituted Ba hexaferrites. • Increased coercivity with Ce{sup 3+} substitution. • Decrease in saturation magnetization and Curie temperature.

A methodology for selecting optimum organizations for space communities

Science.gov (United States)

Ragusa, J. M.

1978-01-01

This paper suggests that a methodology exists for selecting optimum organizations for future space communities of various sizes and purposes. Results of an exploratory study to identify an optimum hypothetical organizational structure for a large earth-orbiting multidisciplinary research and applications (R&A) Space Base manned by a mixed crew of technologists are presented. Since such a facility does not presently exist, in situ empirical testing was not possible. Study activity was, therefore, concerned with the identification of a desired organizational structural model rather than the empirical testing of it. The principal finding of this research was that a four-level project type 'total matrix' model will optimize the effectiveness of Space Base technologists. An overall conclusion which can be reached from the research is that application of this methodology, or portions of it, may provide planning insights for the formal organizations which will be needed during the Space Industrialization Age.

At last! The single-crystal X-ray structure of a naturally occurring sample of the ilmenite-type oxide FeCrO3.

Science.gov (United States)

Pérez-Cruz, María Ana; Elizalde-González, María de la Paz; Escudero, Roberto; Bernès, Sylvain; Silva-González, Rutilo; Reyes-Ortega, Yasmi

2015-10-01

A natural single crystal of the ferrimagnetic oxide FeCrO3, which was found in an opencast mine situated in the San Luis Potosí State in Mexico, has been characterized in order to elucidate some outstanding issues about the actual structure of this material. The single-crystal X-ray analysis unambiguously shows that transition metal cations are segregated in alternating layers normal to the threefold crystallographic axis, affording a structure isomorphous to that of ilmenite (FeTiO3), in the space group R3̅. The possible occurrence of cation antisite and vacancy defects is below the limit of detection available from X-ray data. Structural and magnetic results are in agreement with the coherent slow intergrowth of magnetic phases provided by the two antiferromagnetic corundum-type parent oxides Fe2O3 (hematite) and Cr2O3 (eskolaite). Our results are consistent with the most recent density functional theory (DFT) studies carried out on digital FeCrO3 [Sadat Nabi & Pentcheva (2011). Phys. Rev. B, 83, 214424], and suggest that synthetic samples of FeCrO3 might present a cation distribution different to that of the ilmenite structural type.

NES consensus redefined by structures of PKI-type and Rev-type nuclear export signals bound to CRM1.

Science.gov (United States)

Güttler, Thomas; Madl, Tobias; Neumann, Piotr; Deichsel, Danilo; Corsini, Lorenzo; Monecke, Thomas; Ficner, Ralf; Sattler, Michael; Görlich, Dirk

2010-11-01

Classic nuclear export signals (NESs) confer CRM1-dependent nuclear export. Here we present crystal structures of the RanGTP-CRM1 complex alone and bound to the prototypic PKI or HIV-1 Rev NESs. These NESs differ markedly in the spacing of their key hydrophobic (Φ) residues, yet CRM1 recognizes them with the same rigid set of five Φ pockets. The different Φ spacings are compensated for by different conformations of the bound NESs: in the case of PKI, an α-helical conformation, and in the case of Rev, an extended conformation with a critical proline docking into a Φ pocket. NMR analyses of CRM1-bound and CRM1-free PKI NES suggest that CRM1 selects NES conformers that pre-exist in solution. Our data lead to a new structure-based NES consensus, and explain why NESs differ in their affinities for CRM1 and why supraphysiological NESs bind the exportin so tightly.

A Survey of the Homotopy Properties of Inclusion of Certain Types of Configuration Spaces into the Cartesian Product

Institute of Scientific and Technical Information of China (English)

Daciberg Lima GON(C)ALVES; John GUASCHI

2017-01-01

Let X be a topological space.In this survey the authors consider severaltypes of configuration spaces,namely,the classical (usual) configuration spaces Fn(X)and Dn(X),the orbit configuration spaces FGn(X) and FGn(X)/Sn with respect to a freeaction of a group G on X,and the graph configuration spaces FΓn(X) and FΓn(X)/H,where F is a graph and H is a suitable subgroup of the symmetric group Sn.The orderedconfiguration spaces Fn (X),FGn (X),FΓn(X) are all subsets of the n-fold Cartesian productnП1 X of X with itself,and satisfy FGn(X) (C) Fn(X) (C) Frn(X) (C) nП1 X.If A denotes one of these configuration spaces,the authors analyse the difference between A and nП1 X from a topological and homotopical point of view.The principal results known in the literature concern the usual configuration spaces.The authors are particularly interested in the homomorphism on the level of the homotopy groups of the spaces induced by the inclusion (ι):A → nП1 X,the homotopy type of the homotopy fibre I(ι) of the map (ι) via certain constructions on various spaces that depend on X,and the long exact sequence in homotopy of the fibration involving I(ι) and arising from the inclusion (ι).In this respect,if X is either a surface without boundary,in particular if X is the 2-sphere or the real projective plane,or a space whose universal covering is contractible,or an orbit space Sk/G of the k-dimensional sphere by a free action of a Lie group G,the authors present recent results obtained by themselves for the first case,and in collaboration with Golasi(n)ski for the second and third cases.The authors also briefly indicate some older results relative to the homotopy of these spaces that are related to the problems of interest.In order to motivate various questions,for the remaining types of configuration spaces,a few of their basic properties are described and proved.A list of open questions and problems is given at the end of the paper.

A new type of phase-space path integral

International Nuclear Information System (INIS)

Marinov, M.S.

1991-01-01

Evolution of Wigner's quasi-distribution of a quantum system is represented by means of a path integral in phase space. Instead of the Hamiltonian action, a new functional is present in the integral, and its extrema in the functional space are also given by the classical trajectories. The phase-space paths appear in the integral with real weights, so complex integrals are not necessary. The semiclassical approximation and some applications are discussed briefly. (orig.)

Omicron space habitat—research stage II

Science.gov (United States)

Doule, Ondřej; Šálený, Vratislav; Hérin, Benoît; Rousek, Tomáš

2012-01-01

The design presented in this paper is in response to the revolution in private space activities, the increasing public interest in commercial flights to space and the utilization of structures such as space hotels or private orbital habitats. The baseline for the Omicron design concept is the Russian Salyut derived space station module. Salyut was the first space station to orbit the Earth. Its unique design and technical features were what made the development of space stations Salyut 1-7, MIR and the International Space Station (ISS) Zwezda service module possible. Due to its versatility and the reliable operating launch vehicle Proton, this space module series has the potential to be adapted for space hotel development. This paper proposes a conceptual design of the space habitat called Omicron, with particular focus on interior design for the microgravity environment. The Omicron concepts address the needs of space tourism with a strong emphasis on the safety and comfort of the spaceflight participants. The Omicron habitat supports three inhabitants in nominal conditions (e.g., two passengers and one astronaut). The habitat provides a flexible interior, facilities and spaces dynamically transforming in order to accommodate various types of activities, which will be performed in an organically formed interior supporting spatial orientation and movement in microgravity. The future development potential of Omicron is also considered. The baseline version is composed solely of one rigid module with an inverted cupola for observations. An alternative version offers more space using an inflatable structure. Finally, a combination of multiple Omicron modules enables the creation of a larger orbital habitat. The Omicron's subsystems support a few days visit by trained passengers. The transport to the habitat would be provided e.g., by the Soyuz TMA spacecraft carried by the Soyuz launch vehicle in the early stage of Omicron's development, before a fully reusable