Sample records for vitro structural elements

  1. Structural elements design manual

    CERN Document Server

    Draycott, Trevor


    Gives clear explanations of the logical design sequence for structural elements. The Structural Engineer says: `The book explains, in simple terms, and with many examples, Code of Practice methods for sizing structural sections in timber, concrete,masonry and steel. It is the combination into one book of section sizing methods in each of these materials that makes this text so useful....Students will find this an essential support text to the Codes of Practice in their study of element sizing'.


    Directory of Open Access Journals (Sweden)



    Full Text Available The application of finite element method is analytical when solutions can not be applied for deeper study analyzes static, dynamic or other types of requirements in different points of the structures .In practice it is necessary to know the behavior of the structure or certain parts components of the machine under the influence of certain factors static and dynamic . The application of finite element in the optimization of components leads to economic growth , to increase reliability and durability organs studied, thus the machine itself.

  3. Reliability-Based Optimization of Structural Elements

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard

    In this paper structural elements from an optimization point of view are considered, i.e. only the geometry of a structural element is optimized. Reliability modelling of the structural element is discussed both from an element point of view and from a system point of view. The optimization...

  4. Elements of Regolith Simulant's Cost Structure (United States)

    Rickman, Douglas L.


    The cost of lunar regolith simulants is much higher than many users anticipate. After all, it is nothing more than broken rock. This class will discuss the elements which make up the cost structure for simulants. It will also consider which elements can be avoided under certain circumstances and which elements might be altered by the application of additional research and development.

  5. Structural elements design manual working with Eurocodes

    CERN Document Server

    Draycott, Trevor


    Structural Elements Design Manual: Working With Eurocodes is the structural engineers 'companion volume' to the four Eurocodes on the structural use of timber, concrete, masonry and steelwork. For the student at higher technician or first degree level it provides a single source of information on the behaviour and practical design of the main elements of the building structure. With plenty of worked examples and diagrams, it is a useful textbook not only for students of structural and civil engineering, but also for those on courses in related subjects such as

  6. Advanced finite element method in structural engineering

    CERN Document Server

    Long, Yu-Qiu; Long, Zhi-Fei


    This book systematically introduces the research work on the Finite Element Method completed over the past 25 years. Original theoretical achievements and their applications in the fields of structural engineering and computational mechanics are discussed.

  7. Infinte Periodic Structure of Lightweight Elements

    DEFF Research Database (Denmark)

    Domadiya, Parthkumar Gandalal; Andersen, Lars Vabbersgaard; Sorokin, Sergey


    . Furthermore, lightweight building elements are typically periodic structures that behave as filters for sound propagation within certain frequency ranges (stop bands), thus only allowing transmission within the pass bands. Hence, traditional methods based on statistical energy analysis cannot be used...... for proper dynamic assessment of lightweight buildings. Instead, this paper discusses and compares the use of finite element analysis and a wave approach based on Floquet theory. The present analysis has focus on the effect of periodicity on vibration transmission within semi-infinite beam structures. Two...... models of a semi-infinite Euler-Bernoulli and Timoshenko beam structure with periodic variation of the cross-sectional properties are analyzed. In case of the Euler-Bernoulli beam, vibrational behavior is studied in two dimensions by finite element analysis and Floquet theory. Wave propagation within...

  8. The structural elements of the cosmic web (United States)

    Jones, Bernard J. T.; van de Weygaert, Rien


    In 1970 Zel'dovich published a far-reaching paper presenting a simple equation describing the nonlinear growth of primordial density inhomogeneities. The equation was remarkably successful in explaining the large scale structure in the Universe that we observe: a Universe in which the structure appears to be delineated by filaments and clusters of galaxies surrounding huge void regions. In order to concretise this impression it is necessary to define these structural elements through formal techniques with which we can compare the Zel'dovich model and N-body simulations with the observational data. We present an overview of recent efforts to identify voids, filaments and clusters in both the observed galaxy distribution and in numerical simulations of structure formation. We focus, in particular, on methods that involve no fine-tuning of parameters and that handle scale dependence automatically. It is important that these techniques should result in finding structures that relate directly to the dynamical mechanism of structure formation.

  9. Street as Sustainable City Structural Element (United States)

    Leyzerova, A. V.; Bagina, E. J.


    Sustainability in architecture is nowadays of particular significance in the course of globalization and information density. The technospehere spontaneous development poses a threat to the sustainability of traditional urban forms where a street is one of the essential forming elements in the urban structure. The article proposes to consider formally compositional street features in relation to one of the traditional streets in the historic center of Ekaterinburg. The study examines the street-planning structure, the development of its skeleton elements, silhouette and fabric elevation characteristics as well as the scale characteristics and visual complexity of objects. The study provided architectural and artistic aspects of street sustainability, and limits of the appropriate scale and composition consistency under which the compatibility of alternative compositional forms existing at different times is possible.

  10. Electronic structure theory of the superheavy elements

    Energy Technology Data Exchange (ETDEWEB)

    Eliav, Ephraim, E-mail: [School of Chemistry, Tel Aviv University, 6997801 Tel Aviv (Israel); Fritzsche, Stephan, E-mail: [Helmholtz-Institut Jena, Fröbelstieg 3, D-07743 Jena (Germany); Theoretisch-Physikalisches Institut, Friedrich-Schiller-Universität Jena, D-07743 Jena (Germany); Kaldor, Uzi, E-mail: [School of Chemistry, Tel Aviv University, 6997801 Tel Aviv (Israel)


    High-accuracy calculations of atomic properties of the superheavy elements (SHE) up to element 122 are reviewed. The properties discussed include ionization potentials, electron affinities and excitation energies, which are associated with the spectroscopic and chemical behavior of these elements, and are therefore of considerable interest. Accurate predictions of these quantities require high-order inclusion of relativity and electron correlation, as well as large, converged basis sets. The Dirac–Coulomb–Breit Hamiltonian, which includes all terms up to second order in the fine-structure constant α, serves as the framework for the treatment; higher-order Lamb shift terms are considered in some selected cases. Electron correlation is treated by either the multiconfiguration self-consistent-field approach or by Fock-space coupled cluster theory. The latter is enhanced by the intermediate Hamiltonian scheme, allowing the use of larger model (P) spaces. The quality of the calculations is assessed by applying the same methods to lighter homologs of the SHEs and comparing with available experimental information. Very good agreement is obtained, within a few hundredths of an eV, and similar accuracy is expected for the SHEs. Many of the properties predicted for the SHEs differ significantly from what may be expected by straightforward extrapolation of lighter homologs, demonstrating that the structure and chemistry of SHEs are strongly affected by relativity. The major scientific challenge of the calculations is to find the electronic structure and basic atomic properties of the SHE and assign its proper place in the periodic table. Significant recent developments include joint experimental–computational studies of the excitation spectrum of Fm and the ionization energy of Lr, with excellent agreement of experiment and theory, auguring well for the future of research in the field.

  11. Electrical connection structure for a superconductor element (United States)

    Lallouet, Nicolas; Maguire, James


    The invention relates to an electrical connection structure for a superconductor element cooled by a cryogenic fluid and connected to an electrical bushing, which bushing passes successively through an enclosure at an intermediate temperature between ambient temperature and the temperature of the cryogenic fluid, and an enclosure at ambient temperature, said bushing projecting outside the ambient temperature enclosure. According to the invention, said intermediate enclosure is filled at least in part with a solid material of low thermal conductivity, such as a polyurethane foam or a cellular glass foam. The invention is applicable to connecting a superconductor cable at cryogenic temperature to a device for equipment at ambient temperature.

  12. Motion Structural Optimization Strategy for Rhombic Element Based Foldable Structure

    Directory of Open Access Journals (Sweden)

    Seung Hyun Jeong


    Full Text Available This research presents a new systematical design approach of foldable structure composed of several rhombic elements by applying genetic algorithm. As structural shapes represented by a foldable structure can be easily and dramatically morphed by manipulating rotational directions and angle of joints, the foldable structure has been used for various elementary structural members and engineering mechanisms. However a systematic design approach determining detail rotational angle and directions of unit cells for arbitrary shaped target areas has not been proposed yet. This research contributes to it by developing a new structural optimization method determining optimal angle and rotation directions to cover arbitrary shaped target areas of interest with aggregated rhombic elements. To achieve this purpose, we present an optimization formulation minimizing the sum of distances between each reference joint of an arbitrary shaped target area and its closest outer joints of foldable structure. To find out the outer joint set of a given foldable structure, an efficient geometric analysis method based on Delaunay triangulation is also developed and implemented. To show the validity and limitations of the present approach, several foldable structure design problems for two-dimensional arbitrary shaped target areas are solved with the present optimization procedure.

  13. Structural Variation of Element and Human Disease

    Directory of Open Access Journals (Sweden)

    Songmi Kim


    Full Text Available Transposable elements are one of major sources to cause genomic instability through various mechanisms including de novo insertion, insertion-mediated genomic deletion, and recombination-associated genomic deletion. Among them is Alu element which is the most abundant element, composing ~10% of the human genome. The element emerged in the primate genome 65 million years ago and has since propagated successfully in the human and non-human primate genomes. Alu element is a non-autonomous retrotransposon and therefore retrotransposed using L1-enzyme machinery. The 'master gene' model has been generally accepted to explain Alu element amplification in primate genomes. According to the model, different subfamilies of Alu elements are created by mutations on the master gene and most Alu elements are amplified from the hyperactive master genes. Alu element is frequently involved in genomic rearrangements in the human genome due to its abundance and sequence identity between them. The genomic rearrangements caused by Alu elements could lead to genetic disorders such as hereditary disease, blood disorder, and neurological disorder. In fact, Alu elements are associated with approximately 0.1% of human genetic disorders. The first part of this review discusses mechanisms of Alu amplification and diversity among different Alu subfamilies. The second part discusses the particular role of Alu elements in generating genomic rearrangements as well as human genetic disorders.

  14. Finite Element Vibration and Dynamic Response Analysis of Engineering Structures

    Directory of Open Access Journals (Sweden)

    Jaroslav Mackerle


    Full Text Available This bibliography lists references to papers, conference proceedings, and theses/dissertations dealing with finite element vibration and dynamic response analysis of engineering structures that were published from 1994 to 1998. It contains 539 citations. The following types of structures are included: basic structural systems; ground structures; ocean and coastal structures; mobile structures; and containment structures.

  15. Reliability of Structural Systems with Correlated Elements

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Sørensen, John Dalsgaard


    Calculation of the probability of failure of a system with correlation members is usually a difficult and time-consuming numerical problem. However, for some types of systems with equally correlated elements this calculation can be performed in a simple way. This has suggested two new methods bas...

  16. Binary morphology with spatially variant structuring elements: algorithm and architecture. (United States)

    Hedberg, Hugo; Dokladal, Petr; Owall, Viktor


    Mathematical morphology with spatially variant structuring elements outperforms translation-invariant structuring elements in various applications and has been studied in the literature over the years. However, supporting a variable structuring element shape imposes an overwhelming computational complexity, dramatically increasing with the size of the structuring element. Limiting the supported class of structuring elements to rectangles has allowed for a fast algorithm to be developed, which is efficient in terms of number of operations per pixel, has a low memory requirement, and a low latency. These properties make this algorithm useful in both software and hardware implementations, not only for spatially variant, but also translation-invariant morphology. This paper also presents a dedicated hardware architecture intended to be used as an accelerator in embedded system applications, with corresponding implementation results when targeted for both field programmable gate arrays and application specific integrated circuits.

  17. Nuclear microscopy of sperm cell elemental structure

    Energy Technology Data Exchange (ETDEWEB)

    Bench, G.S.; Balhorn, R.; Friz, A.M.; Freeman, S.P.H.T.


    Theories suggest there is a link between protamine concentrations in individual sperm and male fertility. Previously, biochemical analyses have used pooled samples containing millions of sperm to determine protamine concentrations. These methods have not been able to determine what percentage of morphologically normal sperm are biochemically defective and potentially infertile. Nuclear microscopy has been utilized to measure elemental profiles at the single sperm level. By measuring the amount of phosphorus and sulfur, the total DNA and protamine content in individual sperm from fertile bull and mouse semen have been determined. These values agree with results obtained from other biochemical analyses. Nuclear microscopy shows promise for measuring elemental profiles in the chromatin of individual sperm. The technique may be able to resolve theories regarding the importance of protamines to male fertility and identify biochemical defects responsible for certain types of male infertility.

  18. The structural elements of the cosmic web

    NARCIS (Netherlands)

    Jones, Bernard J. T.; van de Weygaert, Rien; Shandarin, S.; Saar, E.; Einasto, J.


    In 1970 Zel'dovich published a far-reaching paper presenting a simple equation describing the nonlinear growth of primordial density inhomogeneities. The equation was remarkably successful in explaining the large scale structure in the Universe that we observe: a Universe in which the structure

  19. Structural analysis with the finite element method linear statics

    CERN Document Server

    Oñate, Eugenio


    STRUCTURAL ANALYSIS WITH THE FINITE ELEMENT METHOD Linear Statics Volume 1 : The Basis and Solids Eugenio Oñate The two volumes of this book cover most of the theoretical and computational aspects of the linear static analysis of structures with the Finite Element Method (FEM). The content of the book is based on the lecture notes of a basic course on Structural Analysis with the FEM taught by the author at the Technical University of Catalonia (UPC) in Barcelona, Spain for the last 30 years. Volume1 presents the basis of the FEM for structural analysis and a detailed description of the finite element formulation for axially loaded bars, plane elasticity problems, axisymmetric solids and general three dimensional solids. Each chapter describes the background theory for each structural model considered, details of the finite element formulation and guidelines for the application to structural engineering problems. The book includes a chapter on miscellaneous topics such as treatment of inclined supports, elas...

  20. In vitro debonding of orthodontic retainers analyzed with finite element analysis

    NARCIS (Netherlands)

    Milheiro, A.; de Jager, N.; Feilzer, A.J.; Kleverlaan, C.J.


    Objective: The aim of this in vitro study was to determine the load and deflection at failure of different lingual retainers bonded with composite to enamel in a standardized three-point bending test. The results were rationalized with finite element analysis (FEA) models. Materials and methods:

  1. Finite Element Estimation of Meteorite Structural Properties (United States)

    Hart, Kenneth Arthur


    The goal of the project titled Asteroid Threat Assessment at NASA Ames Research Center is to develop risk assessment tools. The expertise in atmospheric entry in the Entry Systems and Technology Division is being used to describe the complex physics of meteor breakup in the atmosphere. The breakup of a meteor is dependent on its structural properties, including homogeneity of the material. The present work describes an 11-week effort in which a literature survey was carried for structural properties of meteoritic material. In addition, the effect of scale on homogeneity isotropy was studied using a Monte Carlo approach in Nastran. The properties were then in a static structural response simulation of an irregularly-shape meteor (138-scale version of Asteroid Itokawa). Finally, an early plan was developed for doctoral research work at Georgia Tech. in the structural failure fragmentation of meteors.

  2. Verification of finite element analysis of fixed partial denture with in vitro electronic strain measurement. (United States)

    Wang, Gaoqi; Zhang, Song; Bian, Cuirong; Kong, Hui


    The purpose of the study was to verify the finite element analysis model of three-unite fixed partial denture with in vitro electronic strain analysis and analyze clinical situation with the verified model. First, strain gauges were attached to the critical areas of a three-unit fixed partial denture. Strain values were measured under 300 N load perpendicular to the occlusal plane. Secondly, a three-dimensional finite element model in accordance with the electronic strain analysis experiment was constructed from the scanning data. And the strain values obtained by finite element analysis and in vitro measurements were compared. Finally, the clinical destruction of the fixed partial denture was evaluated with the verified finite element analysis model. There was a mutual agreement and consistency between the finite element analysis results and experimental data. The finite element analysis revealed that failure will occur in the veneer layer on buccal surface of the connector under occlusal force of 570 N. The results indicate that the electronic strain analysis is an appropriate and cost saving method to verify the finite element model. The veneer layer on buccal surface of the connector is the weakest area in the fixed partial denture. Copyright © 2015 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  3. Optimum element density studies for finite-element thermal analysis of hypersonic aircraft structures (United States)

    Ko, William L.; Olona, Timothy; Muramoto, Kyle M.


    Different finite element models previously set up for thermal analysis of the space shuttle orbiter structure are discussed and their shortcomings identified. Element density criteria are established for the finite element thermal modelings of space shuttle orbiter-type large, hypersonic aircraft structures. These criteria are based on rigorous studies on solution accuracies using different finite element models having different element densities set up for one cell of the orbiter wing. Also, a method for optimization of the transient thermal analysis computer central processing unit (CPU) time is discussed. Based on the newly established element density criteria, the orbiter wing midspan segment was modeled for the examination of thermal analysis solution accuracies and the extent of computation CPU time requirements. The results showed that the distributions of the structural temperatures and the thermal stresses obtained from this wing segment model were satisfactory and the computation CPU time was at the acceptable level. The studies offered the hope that modeling the large, hypersonic aircraft structures using high-density elements for transient thermal analysis is possible if a CPU optimization technique was used.

  4. Nuclear structure notes on element 115 decay chains (United States)

    Rudolph, D.; Sarmiento, L. G.; Forsberg, U.


    Hitherto collected data on more than hundred α-decay chains stemming from element 115 are combined to probe some aspects of the underlying nuclear structure of the heaviest atomic nuclei yet created in the laboratory.

  5. Nuclear Structure Notes on Element 115 Decay Chains


    Rudolph, Dirk; Sarmiento, Luis; Forsberg, Ulrika


    Hitherto collected data on more than hundred α-decay chains stemming from element 115 are combined to probe some aspects of the underlying nuclear structure of the heaviest atomic nuclei yet created in the laboratory.

  6. Finite-element method for above-core structures. [LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Kennedy, J.M.; Belytschko, T.B.


    Three-dimensional finite-element models for the treatment of the nonlinear, transient response of a fast breeder reactor's above-core structures are described. For purposes of treating arbitrarily large rotations, node orientations are described by unit vectors and the deformable elements are treated by a corotational formulation in which the coordinate system is embedded in the elements. Deformable elements may be connected either to nodes directly or through rigid bodies. The time integration is carried out by the Newmark ..beta.. method. These features have been incorporated to form the finite-element program SAFE/RAS (Safety Analysis by Finite Elements/Reactor Analysis and Safety Division). Computations are presented for semianalytical comparisons, simple scoping studies, and Stanford Research Institute (SRI) test comparisons.

  7. Fluid-structure finite-element vibrational analysis (United States)

    Feng, G. C.; Kiefling, L.


    A fluid finite element has been developed for a quasi-compressible fluid. Both kinetic and potential energy are expressed as functions of nodal displacements. Thus, the formulation is similar to that used for structural elements, with the only differences being that the fluid can possess gravitational potential, and the constitutive equations for fluid contain no shear coefficients. Using this approach, structural and fluid elements can be used interchangeably in existing efficient sparse-matrix structural computer programs such as SPAR. The theoretical development of the element formulations and the relationships of the local and global coordinates are shown. Solutions of fluid slosh, liquid compressibility, and coupled fluid-shell oscillation problems which were completed using a temporary digital computer program are shown. The frequency correlation of the solutions with classical theory is excellent.

  8. Lower bound plane stress element for modelling 3D structures

    DEFF Research Database (Denmark)

    Herfelt, Morten Andersen; Poulsen, Peter Noe; Hoang, Linh Cao


    In-plane action is often the primary load-carrying mechanism of reinforced concrete structures. The plate bending action will be secondary, and the behaviour of the structure can be modelled with a reasonable accuracy using a generalised three-dimensional plane stress element. In this paper...

  9. Stochastic Finite Elements in Reliability-Based Structural Optimization

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Engelund, S.


    Application of stochastic finite elements in structural optimization is considered. It is shown how stochastic fields modelling e.g. the modulus of elasticity can be discretized in stochastic variables and how a sensitivity analysis of the reliability of a structural system with respect...

  10. Stochastic Finite Elements in Reliability-Based Structural Optimization

    DEFF Research Database (Denmark)

    Sørensen, John Dalsgaard; Engelund, S.

    Application of stochastic finite elements in structural optimization is considered. It is shown how stochastic fields modelling e.g. the modulus of elasticity can be discretized in stochastic variables and how a sensitivity analysis of the reliability of a structural system with respect...

  11. Hybrid open public space of landscape elements and built structure

    Directory of Open Access Journals (Sweden)

    Gordana Bence


    Full Text Available The trend today in the cities in Europe and elsewhere is in combining landscape elements, built structure and different uses into a complex urban structure. Physical and program interweaving of landscape elements and built structure enables the consumers daily practice of leisure programs – relaxation, recreation and experiencing other cultural, educational and social events in the public green space. On the basis of determinate social changes and new approaches in urban planning practice, analyses of architectural and urban case studies from the point of view of integrating the landscape elements into the urban structure, the article defines the phenomenon of hybrid open public space and proposes methodical guidelines for the planning.

  12. Finite element thermal analysis of convectively-cooled aircraft structures (United States)

    Wieting, A. R.; Thornton, E. A.


    The design complexity and size of convectively-cooled engine and airframe structures for hypersonic transports necessitate the use of large general purpose computer programs for both thermal and structural analyses. Generally thermal analyses are based on the lumped-parameter finite difference technique, and structural analyses are based on the finite element technique. Differences in these techniques make it difficult to achieve an efficient interface. It appears, therefore, desirable to conduct an integrated analysis based on a common technique. A summary is provided of efforts by NASA concerned with the development of an integrated thermal structural analysis capability using the finite element method. Particular attention is given to the development of conduction/forced-convection finite element methodology and applications which illustrate the capabilities of the developed concepts.

  13. LINE-1 elements in structural variation and disease. (United States)

    Beck, Christine R; Garcia-Perez, José Luis; Badge, Richard M; Moran, John V


    The completion of the human genome reference sequence ushered in a new era for the study and discovery of human transposable elements. It now is undeniable that transposable elements, historically dismissed as junk DNA, have had an instrumental role in sculpting the structure and function of our genomes. In particular, long interspersed element-1 (LINE-1 or L1) and short interspersed elements (SINEs) continue to affect our genome, and their movement can lead to sporadic cases of disease. Here, we briefly review the types of transposable elements present in the human genome and their mechanisms of mobility. We next highlight how advances in DNA sequencing and genomic technologies have enabled the discovery of novel retrotransposons in individual genomes. Finally, we discuss how L1-mediated retrotransposition events impact human genomes.

  14. Augmented weak forms and element-by-element preconditioners: Efficient iterative strategies for structural finite elements. A preliminary study (United States)

    Muller, A.; Hughes, T. J. R.


    A weak formulation in structural analysis that provides well conditioned matrices suitable for iterative solutions is presented. A mixed formulation ensures the proper representation of the problem and the constitutive relations are added in a penalized form. The problem is solved by a double conjugate gradient algorithm combined with an element by element approximate factorization procedure. The double conjugate gradient strategy resembles Uzawa's variable-length type algorithms the main difference is the presence of quadratic terms in the mixed variables. In the case of shear deformable beams these terms ensure that the proper finite thickness solution is obtained.

  15. Application of global elements to a reinforced concrete structure; Application des elements globaux a une structure en beton arme

    Energy Technology Data Exchange (ETDEWEB)

    Morand, O


    The dimensioning of nuclear facilities requires to take into account the possible risk of earthquakes. However such installations are generally complex structures with reinforced concrete poles, walls, beams and porches. In this study, a seismic analysis of such a structure is proposed. The use of the Castem 2000 global element code was attempted to dynamically simulate the behaviour of the reinforced concrete elements. However, no suitable modeling has been found for the storeys, the functioning of which being dominated by carrying walls. Concerning the porch-type storeys, monotonous static loads were simulated and provided information on the local and global behaviour of these structures. Thus, representative global elements could be realized for these structures. Results obtained are satisfactory for these storeys which essentially undergo a bending deformation. (J.S.)

  16. An efficient structural finite element for inextensible flexible risers (United States)

    Papathanasiou, T. K.; Markolefas, S.; Khazaeinejad, P.; Bahai, H.


    A core part of all numerical models used for flexible riser analysis is the structural component representing the main body of the riser as a slender beam. Loads acting on this structural element are self-weight, buoyant and hydrodynamic forces, internal pressure and others. A structural finite element for an inextensible riser with a point-wise enforcement of the inextensibility constrain is presented. In particular, the inextensibility constraint is applied only at the nodes of the meshed arc length parameter. Among the virtues of the proposed approach is the flexibility in the application of boundary conditions and the easy incorporation of dissipative forces. Several attributes of the proposed finite element scheme are analysed and computation times for the solution of some simplified examples are discussed. Future developments aim at the appropriate implementation of material and geometric parameters for the beam model, i.e. flexural and torsional rigidity.

  17. Structural elements of critical thinking of nurses in emergency care

    Directory of Open Access Journals (Sweden)

    Maria da Graça Oliveira Crossetti

    Full Text Available The objective of this study was to analyze the structural elements of critical thinking (CT of nurses in the clinical decision-making process. This exploratory, qualitative study was conducted with 20 emergency care nurses in three hospitals in southern Brazil. Data were collected from April to June 2009, and a validated clinical case was applied from which nurses listed health problems, prescribed care and listed the structural elements of CT. Content analysis resulted in categories used to determine priority structural elements of CT, namely theoretical foundations and practical relationship to clinical decision making; technical and scientific knowledge and clinical experience, thought processes and clinical decision making: clinical reasoning and basis for clinical judgments of nurses: patient assessment and ethics. It was concluded that thinking critically is a skill that enables implementation of a secure and effective nursing care process.

  18. Finite element analysis of structures through unified formulation

    CERN Document Server

    Carrera, Erasmo; Petrolo, Marco; Zappino, Enrico


    The finite element method (FEM) is a computational tool widely used to design and analyse  complex structures. Currently, there are a number of different approaches to analysis using the FEM that vary according to the type of structure being analysed: beams and plates may use 1D or 2D approaches, shells and solids 2D or 3D approaches, and methods that work for one structure are typically not optimized to work for another. Finite Element Analysis of Structures Through Unified Formulation deals with the FEM used for the analysis of the mechanics of structures in the case of linear elasticity. The novelty of this book is that the finite elements (FEs) are formulated on the basis of a class of theories of structures known as the Carrera Unified Formulation (CUF). It formulates 1D, 2D and 3D FEs on the basis of the same ''fundamental nucleus'' that comes from geometrical relations and Hooke''s law, and presents both 1D and 2D refined FEs that only have displacement variables as in 3D elements. It also covers 1D...

  19. A study on the nonlinear finite element analysis of reinforced concrete structures: shell finite element formulation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Jin; Seo, Jeong Moon


    The main goal of this research is to establish a methodology of finite element analysis of containment building predicting not only global behaviour but also local failure mode. In this report, we summerize some existing numerical analysis techniques to be improved for containment building. In other words, a complete description of the standard degenerated shell finite element formulation is provided for nonlinear stress analysis of nuclear containment structure. A shell finite element is derived using the degenerated solid concept which does not rely on a specific shell theory. Reissner-Mindlin assumptions are adopted to consider the transverse shear deformation effect. In order to minimize the sensitivity of the constitutive equation to structural types, microscopic material model is adopted. The four solution algorithms based on the standard Newton-Raphson method are discussed. Finally, two numerical examples are carried out to test the performance of the adopted shell medel.

  20. Causation as an Element of Civil Structure of Damages

    Directory of Open Access Journals (Sweden)

    Iliya M. Lipen


    Full Text Available The article deals with the problem of causal nexus in the civil law. Based on analysis of respective regulations similar in their contents in both Russian and Belarusian civil law, the author comes to conclusion that casual nexus is both a condition of contractual liability and an element of civil structure of damages at the same time. Emphasizing the fact that neither legislation nor judicial enforcement require a researcher to make a strict separation between these aspects both in Belarus and Russia, the author argues that accentuation of one of the above aspects (namely, casual nexus as an element of civil structure of damages does have its own significance

  1. Evaluation of an in vitro method to estimate trace elements bioavailability in edible seaweeds. (United States)

    Domínguez-González, Raquel; Romarís-Hortas, Vanessa; García-Sartal, Cristina; Moreda-Piñeiro, Antonio; Barciela-Alonso, María Del Carmen; Bermejo-Barrera, Pilar


    Raw edible seaweed harvested in the Galician coast (Northwestern Spain), including two red seaweed types (Dulse and Nori), three brown seaweed (Kombu, Wakame and Sea Spaghetti), one green seaweed (Sea Lettuce) and one microalgae (Spirulina platensis) were studied to assess trace elements bioavailability using an in vitro method (simulated gastric and intestinal digestion/dialysis). Similarly, a cooked seaweed sample (canned in brine) consisting of a mixture of two brown seaweed (Sea Spaghetti and Furbelows) and a derived product (Agar-Agar) from the red seaweed Gelidiumm sesquipedale, were also included in the study. The total trace element content as well as the non-dialyzable fractions was carried out after a microwave acid digestion of the seaweed samples by inductively coupled plasma-mass spectrometry (ICP-MS). The dialyzable fraction was determined without any pre-treatment by ICP-MS. PIPES buffer solution at a pH of 7.0 and dialysis membranes of 10kDa molecular weight cut off (MWCO) were used for intestinal digestion. Accuracy of the method was assessed by analyzing a NIES-09 certified reference material (Sargasso seaweed). The accuracy of the in vitro procedure was established by a mass balance study which led to good accuracy of the whole in vitro process, after statistical evaluation (95% confidence interval). The highest dialyzability percentages (100±0.2%) were obtained for Dulse in Mn and V. Copyright © 2010 Elsevier B.V. All rights reserved.

  2. Better Finite-Element Analysis of Composite Shell Structures (United States)

    Clarke, Gregory


    A computer program implements a finite-element-based method of predicting the deformations of thin aerospace structures made of isotropic materials or anisotropic fiber-reinforced composite materials. The technique and corresponding software are applicable to thin shell structures in general and are particularly useful for analysis of thin beamlike members having open cross-sections (e.g. I-beams and C-channels) in which significant warping can occur.

  3. 2-D Finite Element Analysis of Massive RC Structures

    DEFF Research Database (Denmark)

    Saabye Ottosen, Niels


    Nonlinear analysis of concrete structures using finite elements is discussed. The applications include a thick-walled top-closure for a pressure vessel as well as the delicate problems of beams failing in shear. The top-closure analysis evaluates the effect of two different failure criteria...

  4. Inverse boundary element calculations based on structural modes

    DEFF Research Database (Denmark)

    Juhl, Peter Møller


    The inverse problem of calculating the flexural velocity of a radiating structure of a general shape from measurements in the field is often solved by combining a Boundary Element Method with the Singular Value Decomposition and a regularization technique. In their standard form these methods sol...

  5. (ajst) finite element analysis of a fluid-structure

    African Journals Online (AJOL)

    6th International Conference on Pressure. Surges, Cambridge, England C2. [9] Wiggert, D. C., Tijsseling, A. S. Fluid transients and fluid-structure interaction in flexible liquid-filled piping. 2001. ASME Applied Mechanics Reviews. Vol. 54. PP455-481. [10] Zienkiewicz O. C. and Taylor, R. L. The finite element method 1989.

  6. Structure of nuclear transition matrix elements for neutrinoless ...

    Indian Academy of Sciences (India)

    Abstract. The structure of nuclear transition matrix elements (NTMEs) required for the study of neutrinoless double- decay within light Majorana neutrino mass mechanism is disassembled in the PHFB model. The NTMEs are calculated using a set of HFB intrinsic wave functions, the reliability of which has been previously ...

  7. Structure of nuclear transition matrix elements for neutrinoless ...

    Indian Academy of Sciences (India)

    Abstract. The structure of nuclear transition matrix elements (NTMEs) required for the study of neutrinoless double-β decay within light Majorana neutrino mass mechanism is disassembled in the PHFB model. The NTMEs are calculated using a set of HFB intrinsic wave functions, the reliability of which has been previously ...

  8. Structural elements recognized by abacavir-induced T cells

    DEFF Research Database (Denmark)

    Yerly, Daniel; Pompeu, Yuri Andreiw; Schutte, Ryan J.


    of autoimmune destruction. The structural elements recognized by drug-specific T cell receptors (TCRs) in vivo are poorly defined. Drug-stimulated T cells express TCRs specific for peptide/HLA complexes, but the characteristics of peptides (sequence, or endogenous or exogenous origin) presented in the context...

  9. Curved Thermopiezoelectric Shell Structures Modeled by Finite Element Analysis (United States)

    Lee, Ho-Jun


    "Smart" structures composed of piezoelectric materials may significantly improve the performance of aeropropulsion systems through a variety of vibration, noise, and shape-control applications. The development of analytical models for piezoelectric smart structures is an ongoing, in-house activity at the NASA Glenn Research Center at Lewis Field focused toward the experimental characterization of these materials. Research efforts have been directed toward developing analytical models that account for the coupled mechanical, electrical, and thermal response of piezoelectric composite materials. Current work revolves around implementing thermal effects into a curvilinear-shell finite element code. This enhances capabilities to analyze curved structures and to account for coupling effects arising from thermal effects and the curved geometry. The current analytical model implements a unique mixed multi-field laminate theory to improve computational efficiency without sacrificing accuracy. The mechanics can model both the sensory and active behavior of piezoelectric composite shell structures. Finite element equations are being implemented for an eight-node curvilinear shell element, and numerical studies are being conducted to demonstrate capabilities to model the response of curved piezoelectric composite structures (see the figure).

  10. Model Reduction in Dynamic Finite Element Analysis of Lightweight Structures

    DEFF Research Database (Denmark)

    Flodén, Ola; Persson, Kent; Sjöström, Anders


    models may be created by assembling models of floor and wall structures into large models of complete buildings. When assembling the floor and wall models, the number of degrees of freedom quickly increases to exceed the limits of computer capacity, at least in a reasonable amount of computational time....... The objective of the analyses presented in this paper is to evaluate methods for model reduction of detailed finite element models of floor and wall structures and to investigate the influence of reducing the number of degrees of freedom and computational cost on the dynamic response of the models in terms....... The drawback of component mode synthesis compared to modelling with structural elements is the increased computational cost, although the number of degrees of freedom is small in comparison, as a result of the large bandwidth of the system matrices....

  11. Finite element solution of transient fluid-structure interaction problems (United States)

    Everstine, Gordon C.; Cheng, Raymond S.; Hambric, Stephen A.


    A finite element approach using NASTRAN is developed for solving time-dependent fluid-structure interaction problems, with emphasis on the transient scattering of acoustic waves from submerged elastic structures. Finite elements are used for modeling both structure and fluid domains to facilitate the graphical display of the wave motion through both media. For the liquid, the use of velocity potential as the fundamental unknown results in a symmetric matrix equation. The approach is illustrated for the problem of transient scattering from a submerged elastic spherical shell subjected to an incident tone burst. The use of an analogy between the equations of elasticity and the wave equation of acoustics, a necessary ingredient to the procedure, is summarized.

  12. Model Reduction in Dynamic Finite Element Analysis of Lightweight Structures

    DEFF Research Database (Denmark)

    Flodén, Ola; Persson, Kent; Sjöström, Anders


    . The objective of the analyses presented in this paper is to evaluate methods for model reduction of detailed finite element models of floor and wall structures and to investigate the influence of reducing the number of degrees of freedom and computational cost on the dynamic response of the models in terms....... The drawback of component mode synthesis compared to modelling with structural elements is the increased computational cost, although the number of degrees of freedom is small in comparison, as a result of the large bandwidth of the system matrices.......The application of wood as a construction material when building multi-storey buildings has many advantages, e.g., light weight, sustainability and low energy consumption during the construction and lifecycle of the building. However, compared to heavy structures, it is a greater challenge to build...

  13. Structural Elements Regulating AAA+ Protein Quality Control Machines

    Directory of Open Access Journals (Sweden)

    Chiung-Wen Chang


    Full Text Available Members of the ATPases Associated with various cellular Activities (AAA+ superfamily participate in essential and diverse cellular pathways in all kingdoms of life by harnessing the energy of ATP binding and hydrolysis to drive their biological functions. Although most AAA+ proteins share a ring-shaped architecture, AAA+ proteins have evolved distinct structural elements that are fine-tuned to their specific functions. A central question in the field is how ATP binding and hydrolysis are coupled to substrate translocation through the central channel of ring-forming AAA+ proteins. In this mini-review, we will discuss structural elements present in AAA+ proteins involved in protein quality control, drawing similarities to their known role in substrate interaction by AAA+ proteins involved in DNA translocation. Elements to be discussed include the pore loop-1, the Inter-Subunit Signaling (ISS motif, and the Pre-Sensor I insert (PS-I motif. Lastly, we will summarize our current understanding on the inter-relationship of those structural elements and propose a model how ATP binding and hydrolysis might be coupled to polypeptide translocation in protein quality control machines.

  14. Engineering computation of structures the finite element method

    CERN Document Server

    Neto, Maria Augusta; Roseiro, Luis; Cirne, José; Leal, Rogério


    This book presents theories and the main useful techniques of the Finite Element Method (FEM), with an introduction to FEM and many case studies of its use in engineering practice. It supports engineers and students to solve primarily linear problems in mechanical engineering, with a main focus on static and dynamic structural problems. Readers of this text are encouraged to discover the proper relationship between theory and practice, within the finite element method: Practice without theory is blind, but theory without practice is sterile. Beginning with elasticity basic concepts and the classical theories of stressed materials, the work goes on to apply the relationship between forces, displacements, stresses and strains on the process of modeling, simulating and designing engineered technical systems. Chapters discuss the finite element equations for static, eigenvalue analysis, as well as transient analyses. Students and practitioners using commercial FEM software will find this book very helpful. It us...

  15. Finite Element Based HWB Centerbody Structural Optimization and Weight Prediction (United States)

    Gern, Frank H.


    This paper describes a scalable structural model suitable for Hybrid Wing Body (HWB) centerbody analysis and optimization. The geometry of the centerbody and primary wing structure is based on a Vehicle Sketch Pad (VSP) surface model of the aircraft and a FLOPS compatible parameterization of the centerbody. Structural analysis, optimization, and weight calculation are based on a Nastran finite element model of the primary HWB structural components, featuring centerbody, mid section, and outboard wing. Different centerbody designs like single bay or multi-bay options are analyzed and weight calculations are compared to current FLOPS results. For proper structural sizing and weight estimation, internal pressure and maneuver flight loads are applied. Results are presented for aerodynamic loads, deformations, and centerbody weight.

  16. Songs as Elements in the Generic Structure of Film Musicals


    Katja Plemenitaš


    The paper focuses on the description of film musicals as a subgenre of the genre family of musicals. Their dramatic structure is examined in terms of the generic elements that constitute the progression of a story expressed through the combination of spoken dialogue, songs and dance. The function of songs in the generic structure of film musicals is examined in the framework of the systemic-functional theory of register and genre. Special attention is given to the role of songs in the unfoldi...

  17. Sandwich Panel as a Structural Element of Overlap

    Directory of Open Access Journals (Sweden)

    Novikov Maxim


    Full Text Available This paper considers the issue of sandwich panels using as load-bearing structural elements. The comparison of deflections and critical failure loads were obtained by the results of the full-scale roof sandwich panels tests conducted by the company “Joris Ide” and the theoretical design, according to the calculation method described in Euronorms. Based on these results it was concluded that sandwich panels can be treated as a load-bearing structure only with more taught manufacturing requirements. Thus, the reduced spread of critical loads can be achieved.

  18. Structural elements and joints - a generator for design explorations

    DEFF Research Database (Denmark)

    Christensen, Jesper Thøger; Damkilde, Lars


    throughout the early design process. Thus, the methodology conceives design as a combination of a top-down and a bottom-up approach. Furthermore, the paper suggests forms of representation to investigate the different scales and ensure that joint, structure and architecture inform each other. Results from......The paper introduces a methodology for structural elements and joints to become a generator for design explorations in the early conceptual design of buildings. To make the design team think about structure and joints, the authors propose to look at design from both the small and the big scale...... using this methodology are exemplified using a group of students in architectural engineering. In the process of designing a proposal for a temporary pavilion in timber, they learnt how design of joints influences structural strength and architectural expression. Implementation of the methodology may...

  19. Selective small-molecule inhibition of an RNA structural element

    Energy Technology Data Exchange (ETDEWEB)

    Howe, John A.; Wang, Hao; Fischmann, Thierry O.; Balibar, Carl J.; Xiao, Li; Galgoci, Andrew M.; Malinverni, Juliana C.; Mayhood, Todd; Villafania, Artjohn; Nahvi, Ali; Murgolo, Nicholas; Barbieri, Christopher M.; Mann, Paul A.; Carr, Donna; Xia, Ellen; Zuck, Paul; Riley, Dan; Painter, Ronald E.; Walker, Scott S.; Sherborne, Brad; de Jesus, Reynalda; Pan, Weidong; Plotkin, Michael A.; Wu, Jin; Rindgen, Diane; Cummings, John; Garlisi, Charles G.; Zhang, Rumin; Sheth, Payal R.; Gill, Charles J.; Tang, Haifeng; Roemer , Terry (Merck)


    Riboswitches are non-coding RNA structures located in messenger RNAs that bind endogenous ligands, such as a specific metabolite or ion, to regulate gene expression. As such, riboswitches serve as a novel, yet largely unexploited, class of emerging drug targets. Demonstrating this potential, however, has proven difficult and is restricted to structurally similar antimetabolites and semi-synthetic analogues of their cognate ligand, thus greatly restricting the chemical space and selectivity sought for such inhibitors. Here we report the discovery and characterization of ribocil, a highly selective chemical modulator of bacterial riboflavin riboswitches, which was identified in a phenotypic screen and acts as a structurally distinct synthetic mimic of the natural ligand, flavin mononucleotide, to repress riboswitch-mediated ribB gene expression and inhibit bacterial cell growth. Our findings indicate that non-coding RNA structural elements may be more broadly targeted by synthetic small molecules than previously expected.

  20. Finite element structural study of the VGOT wind turbine

    Energy Technology Data Exchange (ETDEWEB)

    Otero, A.D. [University of Buenos Aires (Argentina). College of Engineering; Ponta, F.L. [University of Illinois, Urbana, IL (United States). Dept. of Theoretical and Applied Mechanics


    We analyse the implementation of the finite element method to simulate the structural behaviour of the blade-wagons of variable-geometry oval-trajectory (VGOT) Darrieus wind turbines. The key feature of a VGOT machine is that each blade, instead of rotating around a central vertical axis, slides over rails mounted on a wagon formed by a tubular reticulated structure supported by standard train bogies. The structure should be designed to absorb the efforts in the vertical and traverse directions of the railroad due to the aerodynamic loads, the weight of the components and the centrifugal acceleration along the curved tracks. We show some results for the tip deflection and the tip torsion of the blade, the frontal and lateral angle variations in the blade bottom and the Von Misses tensions of five sample beams, all of them in function of the trajectory-length parameter; and some examples of the deformed configuration of the reticulated structure. (author)

  1. Micro structured coupling elements for 3D silicon optical interposer (United States)

    Charania, Sujay; Lüngen, Sebastian; Al-Husseini, Zaid; Killge, Sebastian; Nieweglowski, Krzysztof; Neumann, Niels; Plettemeier, Dirk; Bock, Karlheinz; Bartha, Johann W.


    Current trends in electronic industry, such as Internet of Things (IoT) and Cloud Computing call for high interconnect bandwidth, increased number of active devices and high IO count. Hence the integration of on silicon optical waveguides becomes an alternative approach to cope with the performance demands. The application and fabrication of horizontal (planar) and vertical (Through Silicon Vias - TSVs) optical waveguides are discussed here. Coupling elements are used to connect both waveguide structures. Two micro-structuring technologies for integration of coupling elements are investigated: μ-mirror fabrication by nanoimprint (i) and dicing technique (ii). Nanoimprint technology creates highly precise horizontal waveguides with polymer (refractive index nC = 1.56 at 650 nm) as core. The waveguide ends in reflecting facets aligned to the optical TSVs. To achieve Total Internal Reflection (TIR), SiO2 (nCl = 1.46) is used as cladding. TSVs (diameter 20-40μm in 200-380μm interposer) are realized by BOSCH process1, oxidation and SU-8 filling techniques. To carry out the imprint, first a silicon structure is etched using a special plasma etching process. A polymer stamp is then created from the silicon template. Using this polymer stamp, SU-8 is imprinted aligned to vertical TSVs over Si surface.Waveguide dicing is presented as a second technology to create coupling elements on polymer waveguides. The reflecting mirror is created by 45° V-shaped dicing blade. The goal of this work is to develop coupling elements to aid 3D optical interconnect network on silicon interposer, to facilitate the realization of the emerging technologies for the upcoming years.

  2. Contents of selected elements in the mineral structure of gallstones

    Directory of Open Access Journals (Sweden)

    Kwapuliński Jerzy


    Full Text Available Introduction. In this work, the problem of occurrence and co-occurrence of titanium, lithium, molybdenum, strontium, calcium, magnesium, sodium and potassium in the choleliths of the inhabitants of Częstochowa and Bielsko-Biała district has been presented. The choice of research area was determined by the different mineral structure of suspended dust in the air, as well as the average different occurrence of some other minerals in suspended dust in the air. The aim of the studies was to define the level of accumulation and coincidention of Ti, Li, Mo, Sr, Ca, Mg, Na, K in deposits in the gallbladder. Materials and methods. The content of these particular elements in the gall bladder deposits obtained during cholecystectomy was assessed by means of inductive coupled plasma – atomic emission spectrometry (ICP – AES with accuracy to 0,01 µg/g. Results. The presence of selected elements in the mineral structure of gall bladder deposits is illustrated by the vast statistical characteristic of their occurrence in the inhabitants of Częstochowa and Bielsko-Biała district. This is also documented by the course of quotient changes of the individual element’s content, compared to their sum in the function of changes of their average content in the gall bladder deposits. Conclusions. The level of examined elements in gallbladder deposits was different according to place of living and gender, those differences being better discriminated by geometrical averages.

  3. Multibody Finite Element Method and Application in Hydraulic Structure Analysis

    Directory of Open Access Journals (Sweden)

    Chao Su


    Full Text Available Multibody finite element method is proposed for analysis of contact problems in hydraulic structure. This method is based on the block theory of discontinuous deformation analysis (DDA method and combines advantages of finite element method (FEM and the displacement compatibility equation in classical elastic mechanics. Each single block is analyzed using FEM in corresponding local coordinate system and all contacting blocks need to satisfy the displacement compatibility requirement between any two blocks in a blocky system. It is proved that this method is very efficient and practical to overcome the limitations in DDA method when tackling contact problems, such as the overlap problem and the equal strain assumption. In this paper, detailed theoretical basis and formulations are given. Two numerical examples are performed to verify the proposed method successfully. Furthermore, this method is adopted to study the stability issues of underground houses of a large hydropower station.

  4. Designing synthetic RNAs to determine the relevance of structural motifs in picornavirus IRES elements (United States)

    Fernandez-Chamorro, Javier; Lozano, Gloria; Garcia-Martin, Juan Antonio; Ramajo, Jorge; Dotu, Ivan; Clote, Peter; Martinez-Salas, Encarnacion


    The function of Internal Ribosome Entry Site (IRES) elements is intimately linked to their RNA structure. Viral IRES elements are organized in modular domains consisting of one or more stem-loops that harbor conserved RNA motifs critical for internal initiation of translation. A conserved motif is the pyrimidine-tract located upstream of the functional initiation codon in type I and II picornavirus IRES. By computationally designing synthetic RNAs to fold into a structure that sequesters the polypyrimidine tract in a hairpin, we establish a correlation between predicted inaccessibility of the pyrimidine tract and IRES activity, as determined in both in vitro and in vivo systems. Our data supports the hypothesis that structural sequestration of the pyrimidine-tract within a stable hairpin inactivates IRES activity, since the stronger the stability of the hairpin the higher the inhibition of protein synthesis. Destabilization of the stem-loop immediately upstream of the pyrimidine-tract also decreases IRES activity. Our work introduces a hybrid computational/experimental method to determine the importance of structural motifs for biological function. Specifically, we show the feasibility of using the software RNAiFold to design synthetic RNAs with particular sequence and structural motifs that permit subsequent experimental determination of the importance of such motifs for biological function.

  5. Extended Finite Element Method for Fracture Analysis of Structures

    CERN Document Server

    Mohammadi, Soheil


    This important textbook provides an introduction to the concepts of the newly developed extended finite element method (XFEM) for fracture analysis of structures, as well as for other related engineering applications.One of the main advantages of the method is that it avoids any need for remeshing or geometric crack modelling in numerical simulation, while generating discontinuous fields along a crack and around its tip. The second major advantage of the method is that by a small increase in number of degrees of freedom, far more accurate solutions can be obtained. The method has recently been

  6. The Distinct Element Method - Application to Structures in Jointed Rock

    Energy Technology Data Exchange (ETDEWEB)

    Morris, J.P.; Glen, L.; Blair, S.; Heuze, F.


    The Distinct Element Method (DEM) is a meshfree method with applications to rock mechanics, mining sciences, simulations of nuclear repositories, and the stability of underground structures. Continuum mesh-based methods have been applied successfully to many problems in geophysics. Even if the geology includes fractures and faults, when sufficiently large length scales are considered a continuum approximation may be sufficient. However, a large class of problems exist where individual rock joints must be taken into account. This includes problems where the structures of interest have sizes comparable with the block size. In addition, it is possible that while the structure may experience loads which do no measurable damage to individual blocks, some joints may fail. This may launch smaller blocks as dangerous projectiles or even cause total failure of a tunnel. Traditional grid-based continuum approaches are wholly unsuited to this class of problem. It is possible to introduce discontinuities or slide lines into existing grid-based methods, however, such limited approaches can break down when new contacts form between blocks. The distinct element method (DEM) is an alternative, meshfree approach. The DEM can directly approximate the block structure of the jointed rock using arbitrary polyhedra. Using this approach, preexisting joints are readily incorporated into the DEM model. In addition, the method detects all new contacts between blocks resulting from relative block motion. We will describe the background of the DEM and review previous application of the DEM to geophysical problems. Finally we present preliminary results from a investigation into the stability of underground structures subjected to dynamic loading.

  7. Power flows and Mechanical Intensities in structural finite element analysis (United States)

    Hambric, Stephen A.


    The identification of power flow paths in dynamically loaded structures is an important, but currently unavailable, capability for the finite element analyst. For this reason, methods for calculating power flows and mechanical intensities in finite element models are developed here. Formulations for calculating input and output powers, power flows, mechanical intensities, and power dissipations for beam, plate, and solid element types are derived. NASTRAN is used to calculate the required velocity, force, and stress results of an analysis, which a post-processor then uses to calculate power flow quantities. The SDRC I-deas Supertab module is used to view the final results. Test models include a simple truss and a beam-stiffened cantilever plate. Both test cases showed reasonable power flow fields over low to medium frequencies, with accurate power balances. Future work will include testing with more complex models, developing an interactive graphics program to view easily and efficiently the analysis results, applying shape optimization methods to the problem with power flow variables as design constraints, and adding the power flow capability to NASTRAN.

  8. Songs as Elements in the Generic Structure of Film Musicals

    Directory of Open Access Journals (Sweden)

    Katja Plemenitaš


    Full Text Available The paper focuses on the description of film musicals as a subgenre of the genre family of musicals. Their dramatic structure is examined in terms of the generic elements that constitute the progression of a story expressed through the combination of spoken dialogue, songs and dance. The function of songs in the generic structure of film musicals is examined in the framework of the systemic-functional theory of register and genre. Special attention is given to the role of songs in the unfolding of the narrative. The theoretical observations about the role of songs in the register and genre of film musicals are then illustrated with an analysis of the use of songs in the TV musical High School Musical 2.

  9. Chromatin structure and transposable elements in organismal aging

    Directory of Open Access Journals (Sweden)

    Jason G. Wood


    Full Text Available Epigenetic regulatory mechanisms are increasingly appreciated as central to a diverse array of biological processes, including aging. An association between heterochromatic silencing and longevity has long been recognized in yeast, and in more recent years evidence has accumulated of age-related chromatin changes in C. elegans, Drosophila, and mouse model systems, as well as in the tissue culture-based replicative senescence model of cell aging. In addition, a number of studies have linked expression of transposable elements (TEs, as well as changes in the RNAi pathways that cells use to combat TEs, to the aging process. This review summarizes the recent evidence linking chromatin structure and function to aging, with a particular focus on the relationship of heterochromatin structure to organismal aging.

  10. Finite element model updating of natural fibre reinforced composite structure in structural dynamics

    Directory of Open Access Journals (Sweden)

    Sani M.S.M.


    Full Text Available Model updating is a process of making adjustment of certain parameters of finite element model in order to reduce discrepancy between analytical predictions of finite element (FE and experimental results. Finite element model updating is considered as an important field of study as practical application of finite element method often shows discrepancy to the test result. The aim of this research is to perform model updating procedure on a composite structure as well as trying improving the presumed geometrical and material properties of tested composite structure in finite element prediction. The composite structure concerned in this study is a plate of reinforced kenaf fiber with epoxy. Modal properties (natural frequency, mode shapes, and damping ratio of the kenaf fiber structure will be determined using both experimental modal analysis (EMA and finite element analysis (FEA. In EMA, modal testing will be carried out using impact hammer test while normal mode analysis using FEA will be carried out using MSC. Nastran/Patran software. Correlation of the data will be carried out before optimizing the data from FEA. Several parameters will be considered and selected for the model updating procedure.

  11. Thermomechanical finite element analysis of hot water boiler structure

    Directory of Open Access Journals (Sweden)

    Živković Dragoljub S.


    Full Text Available The paper presents an application of the Finite Elements Method for stress and strain analysis of the hot water boiler structure. The aim of the research was to investigate the influence of the boiler scale on the thermal stresses and strains of the structure of hot water boilers. Results show that maximum thermal stresses appear in the zone of the pipe carrying wall of the first reversing chamber. This indicates that the most critical part of the boiler are weld spots of the smoke pipes and pipe carrying plate, which in the case of significant scale deposits can lead to cracks in the welds and water leakage from the boiler. The nonlinear effects were taken into account by defining the bilinear isotropic hardening model for all boiler elements. Temperature dependency was defined for all relevant material properties, i. e. isotropic coefficient of thermal expansion, Young’s modulus, and isotropic thermal conductivity. The verification of the FEA model was performed by comparing the measured deformations of the hot water boiler with the simulation results. As a reference object, a Viessmann - Vitomax 200 HW boiler was used, with the installed power of 18.2 MW. CAD modeling was done within the Autodesk Inventor, and stress and strain analysis was performed in the ANSYS Software.

  12. 47 CFR 51.509 - Rate structure standards for specific elements. (United States)


    ... 47 Telecommunication 3 2010-10-01 2010-10-01 false Rate structure standards for specific elements... SERVICES (CONTINUED) INTERCONNECTION Pricing of Elements § 51.509 Rate structure standards for specific elements. In addition to the general rules set forth in § 51.507, rates for specific elements shall comply...

  13. Osmotic potential of Zinnia elegans plant material affects the yield and morphology of tracheary elements produced in vitro

    NARCIS (Netherlands)

    Twumasi, P.; Schel, J.; Ieperen, van W.


    The Zinnia elegans cell suspension culture is excellent for xylogenesis studies at the cellular and molecular level, due to the high and synchronous in vitro differentiation of tracheary elements (TEs). The percentage TE differentiation (%TE) in the culture is, however, influenced by a number of

  14. Electronic structure and chemistry of the heaviest elements

    Energy Technology Data Exchange (ETDEWEB)

    Pershina, V. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Fricke, B. [Kassel Univ. (Gesamthochschule) (Germany)


    Progress in the development of relativistic molecular codes has allowed for an adequate description of the electronic structure of the very heavy element compounds, and for the interpretation and prediction of their molecular properties. Most of the theoretical investigations for compounds, interesting from the experimental point of view, have been carried out using the LDF methods. The studied species were group 4, 5 and 6 gas-phase compounds of the transactinides along with their lighter homologs, and their complexes in aqueous solutions. As a result of these calculations, trends within the transition-element groups and within the beginning of the transactinide series for molecular properties such as ionicity, covalence, stability towards oxidation or reduction, crystal-field and spin-orbit effects, bonding, and the influence of relativistic effects on them have been established. In combination with some other models, these calculations allowed for predicting properties measured experimentally: volatility of compounds, redox potentials in solutions and complex formation. Especially promising were predictions of equilibria of reaction using the DS-DV method. Agreement between results of the calculations and experiment confirmed the necessity of doing relativistic MO calculations and the unreliability of the straightforward extrapolations of properties within the chemical groups. (orig.)

  15. Multiscale Finite-Element Modeling of Sandwich Honeycomb Composite Structures

    Directory of Open Access Journals (Sweden)

    Yu. I. Dimitrienko


    Full Text Available The paper presents a developed multi-scale model of sandwich honeycomb structures. The model allows us both to calculate effective elastic-strength characteristics of honeycomb and forced covering of sandwich, and to find a 3D stress-strain state of structures using the threedimensional elastic theory for non- homogeneous media. On the basis of finite element analysis it is shown, that under four-point bending the maximal value of bending and shear stresses in the sandwich honeycomb structures are realized in the zone of applied force and plate support. Here the local stress maxima approximately 2-3 times exceed the “engineering” theoretical plate values of bending and shear stresses in the middle of panel. It is established that at tests for fourpoint bending there is a failure of the honeycomb sandwich panels because of the local adhesion failure rather than because of the covering exfoliation off the honeycomb core in the middle of panel.

  16. Effects of Contamination and Cleaning on Parachute Structural Textile Elements (United States)

    Mollmann, Catherine


    Throughout their lifecycle, parachute textiles come into contact with various other substances. This contact may occur during manufacturing and repair, storage and transportation, packing, or actual use. While this interaction does not always result in negative repercussions, it may cause a loss in material strength. This paper examines the strength degradation due to several contaminants as well as the effects of cleaning agents on common parachute materials. Materials tested were: Kevlar cord and webbing, Nylon broadcloth and webbing, and Vectran cord; all of these constitute the major structural elements for CPAS (Capsule Parachute Assembly System), the parachute system for the NASA Orion Crew Module. Contaminants tested were: sewing machine oil, dried stamping ink, dirt, basting glue, Sergene, and rust. Recommendations for cleaning (or not cleaning) these materials with respect to each of the contaminants are given in this paper, as well as recommendations for future tests.

  17. Distortional Mechanics of Thin-Walled Structural Elements

    DEFF Research Database (Denmark)

    Andreassen, Michael Joachim

    In several industries such as civil, mechanical, and aerospace, thin-walled structures are often used due to the high strength and effective use of the materials. Because of the increased consumption there has been increasing focus on optimizing and more detailed calculations. However, finely...... eigenmodes and may be used in the automatic meshing of approximate distortional beam elements. The magnitude of the eigenvalues thus also gives the natural ordering of the modes. The results are compared to results found using other computational methods taking distortion of the cross section into account...... provides reasonable results with a very small computational cost making it a good alternative to the classical FE calculations and other available methods....

  18. Entamoeba histolytica: cyst-like structures in vitro induction. (United States)

    Barrón-González, M P; Villarreal-Treviño, L; Reséndez-Pérez, D; Mata-Cárdenas, B D; Morales-Vallarta, M R


    The cyst of Entamoeba histolytica is responsible for amebiasis infection. However, no axenic in vitro system exists that promotes mass encystation for studying this process of this human-infecting parasite. Cyst-like structures of E. histolytica obtained in this work were induced using TYI-S-33 media in combination with enterobacterias Escherichia coli and Enterococcus faecalis conditioned media, high CO2 tension and histamine. Cyst-like structures showed the same characteristics of a typical E. histolytica cyst: aggregation, resistance to 0.15% sarcosyl for 10 min, high signal of fluorescence under UV light when stained with 10% calcofluor M2r and the surface topology showed a wrinkled wall. In addition these structures are multinucleated with condensed chromatin attached to nuclear membrane, contain big vacuoles and ribonucleoproteic helices in the cytoplasm and also present a thin cell wall. Last all characteristics are all the same as a typical of E. histolytica cyst.

  19. Future Launch Vehicle Structures - Expendable and Reusable Elements (United States)

    Obersteiner, M. H.; Borriello, G.


    Further evolution of existing expendable launch vehicles will be an obvious element influencing the future of space transportation. Besides this reusability might be the change with highest potential for essential improvement. The expected cost reduction and finally contributing to this, the improvement of reliability including safe mission abort capability are driving this idea. Although there are ideas of semi-reusable launch vehicles, typically two stages vehicles - reusable first stage or booster(s) and expendable second or upper stage - it should be kept in mind that the benefit of reusability will only overwhelm if there is a big enough share influencing the cost calculation. Today there is the understanding that additional technology preparation and verification will be necessary to master reusability and get enough benefits compared with existing launch vehicles. This understanding is based on several technology and system concepts preparation and verification programmes mainly done in the US but partially also in Europe and Japan. The major areas of necessary further activities are: - System concepts including business plan considerations - Sub-system or component technologies refinement - System design and operation know-how and capabilities - Verification and demonstration oriented towards future mission mastering: One of the most important aspects for the creation of those coming programmes and activities will be the iterative process of requirements definition derived from concepts analyses including economical considerations and the results achieved and verified within technology and verification programmes. It is the intention of this paper to provide major trends for those requirements focused on future launch vehicles structures. This will include the aspects of requirements only valid for reusable launch vehicles and those common for expendable, semi-reusable and reusable launch vehicles. Structures and materials is and will be one of the

  20. Finite element analysis of CFRP reinforced silo structure design method (United States)

    Yuan, Long; Xu, Xinsheng


    Because of poor construction, there is a serious problem of concrete quality in the silo project, which seriously affects the safe use of the structure. Concrete quality problems are mainly seen in three aspects: concrete strength cannot meet the design requirements, concrete cracking phenomenon is serious, and the unreasonable concrete vibration leads to a lot of honeycombs and surface voids. Silos are usually reinforced by carbon fiber cloth in order to ensure the safe use of silos. By the example of an alumina silo in a fly ash plant in Binzhou, Shandong Province, the alumina silo project was tested and examined on site. According to filed test results, the actual concrete strength was determined, and the damage causes of the silo was analysed. Then, a finite element analysis model of this silo was established, the CFRP cloth reinforcement method was adopted to strengthen the silo, and other technology like additional reinforcement, rebar planting, carbon fiber bonding technology was also expounded. The research of this paper is of great significance to the design and construction of silo structure.

  1. Experimental evaluation of the structural behaviour of adobe masonry structural elements


    H. Varum; Costa, A; Pereira, H; Almeida, J; Rodrigues, H.; D. Silveira


    Rehabilitation and strengthening of existing adobe masonry constructions have been neglected during the last decades. In Aveiro, Portugal, many adobe buildings present an important level of structural damage and, in many cases, are even near to ruin, having the majority a high vulnerability to seismic actions. To face the lack of information concerning the mechanical properties and structural behaviour of adobe elements, it was developed an experimental campaign. The composition and mechanica...

  2. Validating Finite Element Models of Assembled Shell Structures (United States)

    Hoff, Claus


    The validation of finite element models of assembled shell elements is presented. The topics include: 1) Problems with membrane rotations in assembled shell models; 2) Penalty stiffness for membrane rotations; 3) Physical stiffness for membrane rotations using shell elements with 6 dof per node; and 4) Connections avoiding rotations.

  3. A continuous in vitro method for estimation of the bioavailability of minerals and trace elements in foods : application to breads varying in phytic acid content

    NARCIS (Netherlands)

    Wolters, M.G.E.; Schreuder, H.A.W.; Heuvel, G. van den; Lonkhuijsen, H.J. van; Hermus, R.J.J.; Voragen, A.G.J.


    A continuous in vitro method for the estimation of the bioavailability of minerals and trace elements is presented. This in vitro method is believed to be more representative of in vivo physiological conditions than in vitro methods based on equilibrium dialysis, because dialysable components are

  4. Parallel Finite Element Domain Decomposition for Structural/Acoustic Analysis (United States)

    Nguyen, Duc T.; Tungkahotara, Siroj; Watson, Willie R.; Rajan, Subramaniam D.


    A domain decomposition (DD) formulation for solving sparse linear systems of equations resulting from finite element analysis is presented. The formulation incorporates mixed direct and iterative equation solving strategics and other novel algorithmic ideas that are optimized to take advantage of sparsity and exploit modern computer architecture, such as memory and parallel computing. The most time consuming part of the formulation is identified and the critical roles of direct sparse and iterative solvers within the framework of the formulation are discussed. Experiments on several computer platforms using several complex test matrices are conducted using software based on the formulation. Small-scale structural examples are used to validate thc steps in the formulation and large-scale (l,000,000+ unknowns) duct acoustic examples are used to evaluate the ORIGIN 2000 processors, and a duster of 6 PCs (running under the Windows environment). Statistics show that the formulation is efficient in both sequential and parallel computing environmental and that the formulation is significantly faster and consumes less memory than that based on one of the best available commercialized parallel sparse solvers.

  5. SEM-EDS-Based Elemental Identification on the Enamel Surface after the Completion of Orthodontic Treatment: In Vitro Studies

    Directory of Open Access Journals (Sweden)

    Monika Machoy


    Full Text Available Braces as foreign bodies in the mouth carry a risk of side effects and toxicity to the human body. This article presents the results indicating the possible toxic effects of tools used for cleaning the enamel after the completion of orthodontic treatment. The studies were carried out in vitro. The procedure of enamel etching, bonding orthodontic metal brackets, and enamel cleaning after their removal was performed under laboratory conditions. The enamel microstructure and elements present on its surface were evaluated using the scanning electron microscope (SEM. Silicon and aluminium were found in addition to the tooth building elements.

  6. Fluid-structural interactions using Navier-Stokes flow equations coupled with shell finite element structures (United States)

    Guruswamy, Guru P.; Byun, Chansup


    A computational procedure is presented to study fluid-structural interaction problems for three-dimensional aerospace structures. The flow is modeled using the three-dimensional unsteady Euler/Navier-Stokes equations and solved using the finite-difference approach. The three dimensional structure is modeled using shell/plate finite-element formulation. The two disciplines are coupled using a domain decomposition approach. Accurate procedures both in time and space are developed to combine the solutions from the flow equations with those of the structural equations. Time accuracy is maintained using aeroelastic configuration-adaptive moving grids that are computed every time step. The work done by aerodynamic forces due to structural deformations is preserved using consistent loads. The present procedure is validated by computing the aeroelastic response of a wing and comparing with experiment. Results are illustrated for a typical wing-body configuration.

  7. Finite element analysis of tubular joints in offshore structures ...

    African Journals Online (AJOL)

    This research work was involved in the finite element tool to determine the ultimate strength of initially uncorked joints, which fail by development of tearing fracture at the weld toe. The local approach methodology in contrast to classical fracture mechanics was used. Finite element analysis was done of T-joint plate ...

  8. Influence of disaccharide structure on prebiotic selectivity in vitro. (United States)

    Sanz, María Luz; Gibson, Glenn R; Rastall, Robert A


    To obtain structure-function information of a range of carbohydrates, which are available only in very small quantities, an in vitro fermentation method using 7 mg of carbohydrate, 0.7 mL of basal medium, and 1% (w/v) of fecal bacteria was validated against a pH-controlled batch culture with 150 mL of basal medium and 1.5 g of test carbohydrate. This method was used to determine the influence of different glycosidic linkages and monosaccharide compositions of disaccharides on the selectivity of microbial fermentation. A prebiotic index (PI) was calculated for each disaccharide. Generally, disaccharides with linkages of 1-2, 1-4, and 1-6 generated a high PI score, with kojibiose and sophorose showing the greatest values (21.62 and 18.63, respectively). Apart from 6alpha-mannobiose, mannose-containing disaccharides gave a low PI due to low numbers of bifidobacteria and lactobacilli and an increase in bacteroides. The structure-function information obtained in this study may lead to a predictive understanding of how specific structures are fermented by the human gut microflora.

  9. Stochastic collocation-based finite element of structural nonlinear dynamics with application in composite structures

    Directory of Open Access Journals (Sweden)

    Sepahvand K.


    Full Text Available Stochastic analysis of structures having nonlinearity by means of sampling methods leads to expensive cost in term of computational time. In contrast, non-sampling methods based on the spectral representation of uncertainty are very efficient with comparable accurate results. In this pa- per, the application of spectral methods to nonlinear dynamics of structures with random parameters is investigated. The impact of the parameter randomness on structural responses has been consid- ered. To this end, uncertain parameters and the structure responses are represented using the gPC expansions with unknown deterministic coefficients and random orthogonal polynomial basis. The deterministic finite element model of the structure is used as black-box and it is executed on a set of random collocation points. As the sample structure responses are estimated, a nonlinear optimization process is employed to calculate the unknown coefficients. The method has this main advantage that can be used for complicated nonlinear structural dynamic problems for which the deterministic FEM model has been already developed. Furthermore, it is very time efficient in comparison with sampling methods, as MC simulations. The application of the method is applied to the nonlinear transient analysis of composite beam structures including uncertain quadratic random damping. The results show that the proposed method can capture the large range of uncertainty in input parameters as well as in structural dynamic responses while it is too time-efficient.

  10. Degradation of Mechanical Properties of Multi Perforated Structural Elements

    National Research Council Canada - National Science Library

    Jaeger, Zeev


    ...: This work shall demonstrate the feasibility of an inventive method for a quantitative determination of residual strength of a punctured mechanical element due to holes perforated by many solid fragments...

  11. In vitro debonding of orthodontic retainers analyzed with finite element analysis

    National Research Council Canada - National Science Library

    Milheiro, A; de Jager, N; Feilzer, A.J; Kleverlaan, C.J


    Objective: The aim of this in vitro study was to determine the load and deflection at failure of different lingual retainers bonded with composite to enamel in a standardized three-point bending test...

  12. Multilayer Finite-Element Model Application to Define the Bearing Structure Element Stress State of Launch Complexes

    Directory of Open Access Journals (Sweden)

    V. A. Zverev


    Full Text Available The article objective is to justify the rationale for selecting the multilayer finite element model parameters of the bearing structure of a general-purpose launch complex unit.A typical design element of the launch complex unit, i.e. a mount of the hydraulic or pneumatic cylinder, block, etc. is under consideration. The mount represents a set of the cantilevered axis and external structural cage. The most loaded element of the cage is disk to which a moment is transferred from the cantilevered axis due to actuator effort acting on it.To calculate the stress-strain state of disk was used a finite element method. Five models of disk mount were created. The only difference in models was the number of layers of the finite elements through the thickness of disk. There were models, which had one, three, five, eight, and fourteen layers of finite elements through the thickness of disk. For each model, we calculated the equivalent stresses arising from the action of the test load. Disk models were formed and calculated using the MSC Nastran complex software.The article presents results in the table to show data of equivalent stresses in each of the multi-layered models and graphically to illustrate the changing equivalent stresses through the thickness of disk.Based on these results we have given advice on selecting the proper number of layers in the model allowing a desirable accuracy of results with the lowest run time. In addition, it is concluded that there is a need to use the multi-layer models in assessing the performance of structural elements in case the stress exceeds the allowable one in their surface layers.

  13. Fluid-structure interaction simulations of deformable structures with non-linear thin shell elements (United States)

    Asgharzadeh, Hafez; Hedayat, Mohammadali; Borazjani, Iman; Scientific Computing; Biofluids Laboratory Team


    Large deformation of structures in a fluid is simulated using a strongly coupled partitioned fluid-structure interaction (FSI) approach which is stabilized with under-relaxation and the Aitken acceleration technique. The fluid is simulated using a recently developed implicit Newton-Krylov method with a novel analytical Jacobian. Structures are simulated using a triangular thin-shell finite element formulation, which considers only translational degrees of freedom. The thin-shell method is developed on the top of a previously implemented membrane finite element formulation. A sharp interface immersed boundary method is used to handle structures in the fluid domain. The developed FSI framework is validated against two three-dimensional experiments: (1) a flexible aquatic vegetation in the fluid and (2) a heaving flexible panel in fluid. Furthermore, the developed FSI framework is used to simulate tissue heart valves, which involve large deformations and non-linear material properties. This work was supported by American Heart Association (AHA) Grant 13SDG17220022 and the Center of Computational Research (CCR) of University at Buffalo.

  14. Compact structure and proteins of pasta retard in vitro digestive evolution of branched starch molecular structure. (United States)

    Zou, Wei; Sissons, Mike; Warren, Frederick J; Gidley, Michael J; Gilbert, Robert G


    The roles that the compact structure and proteins in pasta play in retarding evolution of starch molecular structure during in vitro digestion are explored, using four types of cooked samples: whole pasta, pasta powder, semolina (with proteins) and extracted starch without proteins. These were subjected to in vitro digestion with porcine α-amylase, collecting samples at different times and characterizing the weight distribution of branched starch molecules using size-exclusion chromatography. Measurement of α-amylase activity showed that a protein (or proteins) from semolina or pasta powder interacted with α-amylase, causing reduced enzymatic activity and retarding digestion of branched starch molecules with hydrodynamic radius (Rh)100nm. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Elements of Regolith Simulant's Cost Structure--Why Rock Is NOT Cheap (United States)

    Rickman, Douglas L.


    The cost of lunar regolith simulants is much higher than many users anticipate. After all, it is nothing more than broken rock. This class will discuss the elements which make up the cost structure for simulants. It will also consider which elements can be avoided under certain circumstances and which elements might be altered by the application of additional research and development.

  16. The Least Squares Stochastic Finite Element Method in Structural Stability Analysis of Steel Skeletal Structures (United States)

    Kamiński, M.; Szafran, J.


    The main purpose of this work is to verify the influence of the weighting procedure in the Least Squares Method on the probabilistic moments resulting from the stability analysis of steel skeletal structures. We discuss this issue also in the context of the geometrical nonlinearity appearing in the Stochastic Finite Element Method equations for the stability analysis and preservation of the Gaussian probability density function employed to model the Young modulus of a structural steel in this problem. The weighting procedure itself (with both triangular and Dirac-type) shows rather marginal influence on all probabilistic coefficients under consideration. This hybrid stochastic computational technique consisting of the FEM and computer algebra systems (ROBOT and MAPLE packages) may be used for analogous nonlinear analyses in structural reliability assessment.

  17. Structural Responses and Finite Element Modeling of Hakka Tulou Rammed Earth Structures (United States)

    Sranislawski, Daniel

    Hakka Tulous are rammed earth structures that have survived the effects of aging and natural elements upwards of even over a thousand years. These structures have housed the Hakka people of the Fujian Province, China in natural yet modern housing that has provided benefits over newer building materials. The key building material, rammed earth, which is used for the walls of the Hakka Tulou structures, has provided structural stability along with thermal comfort to the respective inhabitants of the Hakka Tulous. Through material testing and analysis this study has examined how the Tulou structures have maintained their structural stability while also providing thermal comfort. Reports of self healing cracks in the rammed earth walls were also analyzed for their validity in this study. The study has found that although the story of the self healing crack cannot be validated, there is reason to believe that with the existence of lime, some type of autogenous healing could occur on a small scale. The study has also found, through the use of nondestructive testing, that both the internal wooden systems (flooring, roof, and column support) and the rammed earth walls, are still structurally sound. Also, rammed earth's high thermal mass along with the use of sufficient shading has allowed for a delay release of heat energy from the walls of the Tulous, thus providing thermal comfort that can be felt during both night and day temperatures. The Hakka Tulou structures have been found to resist destruction from natural disasters such as strong earthquakes even when more modern construction has not. Through finite element modeling, this study has shown that the high volume of rammed earth used in the construction of the Hakka Tulous helps dissipate lateral force energy into much lower stresses for the rammed earth wall. This absorption of lateral force energy allows the rammed earth structures to survive even the strongest of earthquakes experienced in the region. The Hakka

  18. Finite element normal mode analysis of resistance welding jointed of dissimilar plate hat structure (United States)

    Nazri, N. A.; Sani, M. S. M.


    Structural joints offer connection between structural element (beam, plate, solid etc.) in order to build a whole assembled structure. The complex behaviour of connecting elements plays a valuable role in characteristics of dynamic such as natural frequencies and mode shapes. In automotive structures, the trustworthiness arrangement of the structure extremely depends on joints. In this paper, top hat structure is modelled and designed with spot welding joint using dissimilar materials which is mild steel 1010 and stainless steel 304, using finite element software. Different types of connector elements such as rigid body element (RBE2), welding joint element (CWELD), and bar element (CBAR) are applied to represent real connection between two dissimilar plates. Normal mode analysis is simulated with different types of joining element in order to determine modal properties. Natural frequencies using RBE2, CBAR and CWELD are compared to equivalent rigid body method. Connection that gives the lowest percentage error among these three will be selected as the most reliable joining for resistance spot weld. From the analysis, it is shown that CWELD is better compared to others in term of weld joining among dissimilar plate materials. It is expected that joint modelling of finite element plays significant role in structural dynamics.

  19. National Assessment of Oil and Gas Project - Florida Peninsula Province (050) Positive Structural Elements (United States)

    U.S. Geological Survey, Department of the Interior — The Positive Structural Elements coverage maps, in the form of polygons, are known structural highs within the province that commonly define a basin proper or...

  20. Finite element analysis of ship structural connections (fracture of ships)

    African Journals Online (AJOL)

    The stress analysis for a right angled welded joint is characterized with some level of difficulty when assessing results from finite element analysis. Setting up the model itself and undertaking the analysis needs some skill and also takes longer time to interpret the results. This paper, reports of some work done to derive ...

  1. In vitro element release and biological aspects of base?metal alloys for metal-ceramic applications


    Holm, Charlotta; Morisbak, Else; Kalfoss, Torill; Dahl, Jon E.


    Abstract Objective: The aims of this study were to investigate the release of element from, and the biological response in vitro to, cobalt?chromium alloys and other base?metal alloys used for the fabrication of metal-ceramic restorations. Material and methods: Eighteen different alloys were investigated. Nine cobalt?chromium alloys, three nickel?chromium alloys, two cobalt?chromium?iron alloys, one palladium?silver alloy, one high-noble gold alloy, titanium grade II and one type III copper?a...

  2. Structural optimisation of cage induction motors using finite element analysis (United States)

    Palko, S.

    The current trend in motor design is to have highly efficient, low noise, low cost, and modular motors with a high power factor. High torque motors are useful in applications like servo motors, lifts, cranes, and rolling mills. This report contains a detailed review of different optimization methods applicable in various design problems. Special attention is given to the performance of different methods, when they are used with finite element analysis (FEA) as an objective function, and accuracy problems arising from the numerical simulations. Also an effective method for designing high starting torque and high efficiency motors is presented. The method described in this work utilizes FEA combined with algorithms for the optimization of the slot geometry. The optimization algorithm modifies the position of the nodal points in the element mesh. The number of independent variables ranges from 14 to 140 in this work.

  3. Application of Finite Element Method to Analyze Inflatable Waveguide Structures (United States)

    Deshpande, M. D.


    A Finite Element Method (FEM) is presented to determine propagation characteristics of deformed inflatable rectangular waveguide. Various deformations that might be present in an inflatable waveguide are analyzed using the FEM. The FEM procedure and the code developed here are so general that they can be used for any other deformations that are not considered in this report. The code is validated by applying the present code to rectangular waveguide without any deformations and comparing the numerical results with earlier published results.

  4. Parametric dynamic structural components for prefabricated reinforced concrete elements


    Česnik, Jure


    Advanced 3D modelling computer programs for authoring of building projects are gaining on popularity among civil engineers and architects and are thus developing with lightning speed. One of the main areas of development are parametric dynamic components and their use in BIM environments. The first part of the presented work deals with the development and use of parametric dynamic components in BIM software, focusing on prefabricated construction elements. It also explains how ...

  5. On modelling three-dimensional piezoelectric smart structures with boundary spectral element method (United States)

    Zou, Fangxin; Aliabadi, M. H.


    The computational efficiency of the boundary element method in elastodynamic analysis can be significantly improved by employing high-order spectral elements for boundary discretisation. In this work, for the first time, the so-called boundary spectral element method is utilised to formulate the piezoelectric smart structures that are widely used in structural health monitoring (SHM) applications. The resultant boundary spectral element formulation has been validated by the finite element method (FEM) and physical experiments. The new formulation has demonstrated a lower demand on computational resources and a higher numerical stability than commercial FEM packages. Comparing to the conventional boundary element formulation, a significant reduction in computational expenses has been achieved. In summary, the boundary spectral element formulation presented in this paper provides a highly efficient and stable mathematical tool for the development of SHM applications.

  6. Hair Trace Element and Electrolyte Content in Women with Natural and In Vitro Fertilization-Induced Pregnancy. (United States)

    Skalny, Anatoly V; Tinkov, Alexey A; Voronina, Irina; Terekhina, Olga; Skalnaya, Margarita G; Kovas, Yulia


    The objective of the present study was to perform comparative analysis of hair trace element content in women with natural and in vitro fertilization (IVF)-induced pregnancy. Hair trace element content in 33 women with IVF-induced pregnancy and 99 age- and body mass index-matched control pregnant women (natural pregnancy) was assessed using inductively coupled plasma mass spectrometry. The results demonstrated that IVF-pregnant women are characterized by significantly lower hair levels of Cu, Fe, Si, Zn, Ca, Mg, and Ba at p iron, zinc, calcium, and magnesium deficiency and arsenic overload in women with IVF-induced pregnancy. The obtained data indicate the necessity of regular monitoring of micronutrient status in IVF-pregnant women in order to prevent potential deleterious effects of altered mineral homeostasis.

  7. Extension of the Limits of the Xdh Structural Element in DROSOPHILA MELANOGASTER (United States)

    Gelbart, William; McCarron, Margaret; Chovnick, Arthur


    Experiments expanding the array of mutants affecting the xanthine dehydrogenase (XDH) structural element in Drosophila melanogaster are described. These include rosy eye color mutants which exhibit interallelic complementation, and mutants with normal eye color but lowered levels of XDH. Evidence is presented which argues that these are structural alterations in the enzyme. Recombination experiments were performed using these mutants as well as some electrophoretic variants. The two ends of the rosy locus are marked with mutant sites which are clearly structural in nature; the XDH structural element and the rosy null mutant map are completely concordant. A possible procedure to recover control element mutants is described. PMID:826444

  8. Language specific narrative text structure elements in multilingual ...

    African Journals Online (AJOL)

    structure' to both teach narrative structure to children as well as to assess children's narrative skills in ..... that events have to be “construed” as they are often seen as entities which only exist in the mind of sapient beings and not as entities .... One-to-many mappings are evident, for example, in narratives elicited by using the.

  9. Kink structures induced in nickel-based single crystal superalloys by high-Z element migration

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Fei; Zhang, Jianxin [Key Laboratory for Liquid Structure and Heredity of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Mao, Shengcheng [Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124 (China); Jiang, Ying [Center of Electron Microscopy and State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Feng, Qiang [National Center for Materials Service Safety, University of Science and Technology Beijing, Beijing 100083 (China); State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Shen, Zhenju; Li, Jixue; Zhang, Ze [Center of Electron Microscopy and State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Han, Xiaodong [Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124 (China)


    Highlights: • Innovative kink structures generate at the γ/γ′ interfaces in the crept superalloy. • Clusters of heavy elements congregate at the apex of the kinks. • Dislocation core absorbs hexagonal structural high-Z elements. - Abstract: Here, we investigate a new type of kink structure that is found at γ/γ′ interfaces in nickel-based single crystal superalloys. We studied these structures at the atomic and elemental level using aberration corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). The core of the dislocation absorbs high-Z elements (i.e., Co and Re) that adopt hexagonal arrangements, and it extrudes elements (i.e., Ni and Al) that adopt face centered cubic (fcc) structures. High-Z elements (i.e., Ta and W) and Cr, which is a low-Z element, are stabilized in body centered cubic (bcc) arrangements; Cr tends to behave like Re. High-Z elements, which migrate and adopt a hexagonal structure, induce kink formation at γ/γ′ interfaces. This process must be analyzed to fully understand the kinetics and dynamics of creep in nickel-based single crystal superalloys.

  10. Philosophy of mathematics and deductive structure in Euclid's elements

    CERN Document Server

    Mueller, Ian


    A survey of Euclid's Elements, this text provides an understanding of the classical Greek conception of mathematics. It offers a well-rounded perspective, examining similarities to modern views as well as differences. Rather than focusing strictly on historical and mathematical issues, the book examines philosophical, foundational, and logical questions.Although comprehensive in its treatment, this study represents a less cumbersome, more streamlined approach than the classic three-volume reference by Sir Thomas L. Heath (also available from Dover Publications). To make reading easier and to f

  11. In vitro structure-toxicity relationship of chalcones in human hepatic stellate cells. (United States)

    Zenger, Katharina; Dutta, Subhajit; Wolff, Horst; Genton, Marc G; Kraus, Birgit


    Xanthohumol (XN), the major prenylated chalcone from hops (Humulus lupulus L.), has received much attention within the last years, due to its multiple pharmacological activities including anti-proliferative, anti-inflammatory, antioxidant, pro-apoptotic, anti-bacterial and anti-adhesive effects. However, there exists a huge number of metabolites and structurally-related chalcones, which can be expected, or are already known, to exhibit various effects on cells. We have therefore analyzed the effects of XN and 18 other chalcones in a panel, consisting of multiple cell-based assays. Readouts of these assays addressed distinct aspects of cell-toxicity, like proliferation, mitochondrial health, cell cycle and other cellular features. Besides known active structural elements of chalcones, like the Michael system, we have identified several moieties that seem to have an impact on specific effects and toxicity in human liver cells in vitro. Based on these observations, we present a structure-toxicity model, which will be crucial to understand the molecular mechanisms of wanted effects and unwanted side-effects of chalcones. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  12. In vitro structure-toxicity relationship of chalcones in human hepatic stellate cells

    KAUST Repository

    Zenger, Katharina


    Xanthohumol (XN), the major prenylated chalcone from hops (Humulus lupulus L.), has received much attention within the last years, due to its multiple pharmacological activities including anti-proliferative, anti-inflammatory, antioxidant, pro-apoptotic, anti-bacterial and anti-adhesive effects. However, there exists a huge number of metabolites and structurally-related chalcones, which can be expected, or are already known, to exhibit various effects on cells. We have therefore analyzed the effects of XN and 18 other chalcones in a panel, consisting of multiple cell-based assays. Readouts of these assays addressed distinct aspects of cell-toxicity, like proliferation, mitochondrial health, cell cycle and other cellular features. Besides known active structural elements of chalcones, like the Michael system, we have identified several moieties that seem to have an impact on specific effects and toxicity in human liver cells in vitro. Based on these observations, we present a structure-toxicity model, which will be crucial to understand the molecular mechanisms of wanted effects and unwanted side-effects of chalcones.

  13. Inverse Finite Element Method Investigation for Adaptive Structures Project (United States)

    National Aeronautics and Space Administration — This research project is evaluating an innovative technique that uses fiber optic strain sensors to measure structural deformations and full field strains. An...

  14. Design and in vitro testing of a voice-producing element for laryngectomized patients

    NARCIS (Netherlands)

    De Vries, MP; Van der Plaats, A; Van der Torn, M; Mahieu, HF; Schutte, HK; Verkerke, GJ

    A voice-producing element has been developed to improve speech qualify after laryngectomy. The design process started with the formulation of a list of requirements. The lip principle has the best potential for fulfilling the requirements. A numerical model was made to find the optimal geometry of

  15. Fluid-structure interactions models, analysis and finite elements

    CERN Document Server

    Richter, Thomas


    This book starts by introducing the fundamental concepts of mathematical continuum mechanics for fluids and solids and their coupling. Special attention is given to the derivation of variational formulations for the subproblems describing fluid- and solid-mechanics as well as the coupled fluid-structure interaction problem. Two monolithic formulations for fluid-structure interactions are described in detail: the well-established ALE formulation and the modern Fully Eulerian formulation, which can effectively deal with problems featuring large deformation and contact. Further, the book provides details on state-of-the-art discretization schemes for fluid- and solid-mechanics and considers the special needs of coupled problems with interface-tracking and interface-capturing techniques. Lastly, advanced topics like goal-oriented error estimation, multigrid solution and gradient-based optimization schemes are discussed in the context of fluid-structure interaction problems.

  16. In vitro element release and biological aspects of base–metal alloys for metal-ceramic applications (United States)

    Holm, Charlotta; Morisbak, Else; Kalfoss, Torill; Dahl, Jon E.


    Abstract Objective: The aims of this study were to investigate the release of element from, and the biological response in vitro to, cobalt–chromium alloys and other base–metal alloys used for the fabrication of metal-ceramic restorations. Material and methods: Eighteen different alloys were investigated. Nine cobalt–chromium alloys, three nickel–chromium alloys, two cobalt–chromium–iron alloys, one palladium–silver alloy, one high-noble gold alloy, titanium grade II and one type III copper–aluminium alloy. Pure copper served as positive control. The specimens were prepared according to the ISO standards for biological and corrosion testing. Passive leaching of elements was measured by using Inductively Coupled Plasma – Mass Spectrometry (ICP-MS) after incubation in cell culture media, MEM, for 3 days. Corrosion testing was carried out in 0.9% sodium chloride (NaCl) and 1% lactic acid for 7 days, and the element release was measured by Inductively Coupled Plasma – Optical Emission Spectroscopy (ICP-OES). The biological response from the extract solutions was measured though MTT cytotoxicity testing and the Hen's egg test-chorio-allantoic membrane (HET-CAM) technique for irritationt. Results: The corrosion test showed similar element release from base-metal alloys compared to noble alloys such as gold. Apart from the high-copper alloy, all alloys expressed low element release in the immersion test, no cytotoxic effect in the MTT test, and were rated non-irritant in the HET-CAM test. Conclusions: Minimal biological response was observed for all the alloys tested, with the exception of the high-copper alloy. PMID:28642904

  17. sp3-hybridized framework structure of group-14 elements discovered by genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Manh Cuong [Ames Laboratory; Zhao, Xin [Ames Laboratory; Wang, Cai-Zhuang [Ames Laboratory; Ho, Kai-Ming [Ames Laboratory


    Group-14 elements, including C, Si, Ge, and Sn, can form various stable and metastable structures. Finding new metastable structures of group-14 elements with desirable physical properties for new technological applications has attracted a lot of interest. Using a genetic algorithm, we discovered a new low-energy metastable distorted sp3-hybridized framework structure of the group-14 elements. It has P42/mnm symmetry with 12 atoms per unit cell. The void volume of this structure is as large as 139.7Å3 for Si P42/mnm, and it can be used for gas or metal-atom encapsulation. Band-structure calculations show that P42/mnm structures of Si and Ge are semiconducting with energy band gaps close to the optimal values for optoelectronic or photovoltaic applications. With metal-atom encapsulation, the P42/mnm structure would also be a candidate for rattling-mediated superconducting or used as thermoelectric materials.

  18. Probabilistic finite element analysis of high strength steel structures

    NARCIS (Netherlands)

    Waarts, P.H.; Vrouwenvelder, A.C.W.M.


    In structural steel design the ultimate design limit is governed by full cross-sectional plasticity, where an elastic-perfectly plastic material behaviour is used. Hardening of the material is not used. Some loads are not considered such as settlements of supports and temperature loads in static

  19. Structural elements of the right to the truth

    Directory of Open Access Journals (Sweden)

    Luis Andrés Fajardo Arturo


    Full Text Available This article refers specifically to the current state of the discussion on the basic legal structure of the right to truth, its size and degree of legality and reports initial results on the evaluation of the models adopted for peace in Colombia, in light of the international standards and practices.

  20. Material model for non-linear finite element analyses of large concrete structures

    NARCIS (Netherlands)

    Engen, Morten; Hendriks, M.A.N.; Øverli, Jan Arve; Åldstedt, Erik; Beushausen, H.


    A fully triaxial material model for concrete was implemented in a commercial finite element code. The only required input parameter was the cylinder compressive strength. The material model was suitable for non-linear finite element analyses of large concrete structures. The importance of including

  1. Structure and transcriptional impact of divergent repetitive elements inserted within Phanerochaete chrysosporium strain RP-78 genes (United States)

    Luis F. Larrondo; Paulo Canessa; Rafael Vicuna; Philip Stewart; Amber Vanden Wymelenberg; Dan Cullen


    We describe the structure, organization, and transcriptional impact of repetitive elements within the lignin-degrading basidiomycete, Phanerochaete chrysosporium. Searches of the P. chrysosporium genome revealed five copies of pce1, a 1,750-nt non-autonomous, class II element. Alleles encoding a putative glucosyltransferase and a cytochrome P450 harbor pce insertions...

  2. Elements Of The Arabian Syiir In The Qurans Structure

    Directory of Open Access Journals (Sweden)

    Masan Hamid


    Full Text Available The Quran is a Muslim holy book using Arabic with the dialect of the Quraish tribe. Textually the composition or sequence in verses of the Quran contains musicality which when combined with the musicality of poetry or Arabic syiir rhyme both have suitability especially in conformity with 5 five elements of poetry namely Sentence Rhythm Poems Imagination and Deliberate. The opinion of the scholars and the Arabic experts on the existence of poetic aspects in the language of the Quran has occurred in contradictory form some agree and some are not. For those who agree thought one form of the beauty of the Quranic language is a match between the musicality contained in the composition of the verses of the Quran with the musicals of the traditional Arab syiir syiir multazam especially in terms of rhythm And his poem. Meanwhile for the scholars who refuse they argue the Quran is a divine word while the syiir and the poems are human words all types or genres of literature are the creation of shamans imaginers and fanciers.

  3. Considerations Regarding the Damage of the Constructions Structural Elements

    Directory of Open Access Journals (Sweden)

    Vladimir Corobceanu


    Full Text Available The damage processes of the reinforced concrete constructions are very complex due to the relationship between the adopted structural conceptions, the climate conditions for display, the composition of the concrete, the quality of the execution process and the synergetic action of the destructive agents. The measures to be taken against premature damage of the reinforced concrete regard the design, the execution process, the exploitation conditions and the protection techniques.

  4. Finite Element Study of Container Structure under Normal and High Temperature

    National Research Council Canada - National Science Library

    Zha, Xiaoxiong; Zuo, Yang


    ...) are obtained and compared with the standard temperature curve of ISO-834. Secondly, using the software of Abaqus, a full scale finite element model of multilayer container structure is established...

  5. Mitigation of Flanking Noise Transmission in Periodic Structures of Lightweight Elements

    DEFF Research Database (Denmark)

    Domadiya, Parthkumar Gandalal

    through structural junctions and radiates into neighbouring rooms. To diminish the flanking transmission of sound, frames are usually designed with single or double studs or constructed with layers of foam or another viscoelastic material. This thesis is investigating the behaviour of flanking noise...... transmission in periodic structures of lightweight elements by employing various numerical, analytical and experimental methods. At first, three dimensional finite-element (FE) models of a Z-shaped lightweight panel structure based on various frame designs, inclusion of air and structural coupling between...... elements are considered for describing flanking noise transmission through panels. It is assumed that the ribs are fully fixed to the plates in case of various frame designs, and a parametric study is carried out on the centre panel with regard to various spacing between the ribs. Solid finite elements...

  6. Description of selected structural elements of composite foams using statistical methods

    Directory of Open Access Journals (Sweden)

    K. Gawdzińska


    Full Text Available This article makes use of images from a computer tomograph for the description of selected structure elements of metal and compositefoams by means of statistical methods. Besides, compression stress of the tested materials has been determined.

  7. Design of three-element dynamic vibration absorber for damped linear structures (United States)

    Anh, N. D.; Nguyen, N. X.; Hoa, L. T.


    The standard type of dynamic vibration absorber (DVA) called the Voigt DVA is a classical model and has long been investigated. In the paper, we will consider an optimization problem of another model of DVA that is called three-element type DVA for damped primary structures. Unlike the standard absorber configuration, the three-element DVA contains two spring elements in which one is connected to a dashpot in series and the other is placed in parallel. There have been some studies on the design of the three-element DVA for undamped primary structures. Those studies have shown that the three-element DVA produces better performance than the Voigt DVA does. When damping is present at the primary system, to the best knowledge of the authors, there has been no study on the three-element dynamic vibration absorber. This work presents a simple approach to determine the approximate analytical solutions for the H∞ optimization of the three-element DVA attached to the damped primary structure. The main idea of the study is based on the criteria of the equivalent linearization method in order to replace approximately the original damped structure by an equivalent undamped one. Then the approximate analytical solution of the DVA's parameters is given by using known results for the undamped structure obtained. The comparisons have been done to verify the effectiveness of the obtained results.

  8. Non-Linear Three Dimensional Finite Elements for Composite Concrete Structures

    Directory of Open Access Journals (Sweden)

    O. Kohnehpooshi

    Full Text Available Abstract The current investigation focused on the development of effective and suitable modelling of reinforced concrete component with and without strengthening. The modelling includes physical and constitutive models. New interface elements have been developed, while modified constitutive law have been applied and new computational algorithm is utilised. The new elements are the Truss-link element to model the interaction between concrete and reinforcement bars, the interface element between two plate bending elements and the interface element to represent the interfacial behaviour between FRP, steel plates and concrete. Nonlinear finite-element (FE codes were developed with pre-processing. The programme was written using FORTRAN language. The accuracy and efficiency of the finite element programme were achieved by analyzing several examples from the literature. The application of the 3D FE code was further enhanced by carrying out the numerical analysis of the three dimensional finite element analysis of FRP strengthened RC beams, as well as the 3D non-linear finite element analysis of girder bridge. Acceptable distributions of slip, deflection, stresses in the concrete and FRP plate have also been found. These results show that the new elements are effective and appropriate to be used for structural component modelling.

  9. A DEAD-Box Helicase Mediates an RNA Structural Transition in the HIV-1 Rev Response Element. (United States)

    Hammond, John A; Lamichhane, Rajan; Millar, David P; Williamson, James R


    Nuclear export of partially spliced or unspliced HIV-1 RNA transcripts requires binding of the viral protein regulator of expression of virion (Rev) to the Rev response element (RRE) and subsequent oligomerization in a cooperative manner. Cellular DEAD-box helicase DEAD-box protein 1 (DDX1) plays a role in HIV replication, interacting with and affecting Rev-containing HIV transcripts in vivo, interacting directly with the RRE and Rev in vitro, and promoting Rev oligomerization in vitro. Binding of DDX1 results in enhancement of Rev oligomerization on the RRE that is correlated with an RNA structural change within the RRE that persists even after dissociation of DDX1. Furthermore, this structural transition is likely located within the three-way junction of stem II of the RRE that is responsible for initial Rev binding. This discovery of the stem II structural transition leads to a model wherein DDX1 can act as an RNA chaperone, folding stem IIB into a proper Rev binding conformation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Finite element modeling of nanotube structures linear and non-linear models

    CERN Document Server

    Awang, Mokhtar; Muhammad, Ibrahim Dauda


    This book presents a new approach to modeling carbon structures such as graphene and carbon nanotubes using finite element methods, and addresses the latest advances in numerical studies for these materials. Based on the available findings, the book develops an effective finite element approach for modeling the structure and the deformation of grapheme-based materials. Further, modeling processing for single-walled and multi-walled carbon nanotubes is demonstrated in detail.

  11. Non-linear finite element analysis in structural mechanics

    CERN Document Server

    Rust, Wilhelm


    This monograph describes the numerical analysis of non-linearities in structural mechanics, i.e. large rotations, large strain (geometric non-linearities), non-linear material behaviour, in particular elasto-plasticity as well as time-dependent behaviour, and contact. Based on that, the book treats stability problems and limit-load analyses, as well as non-linear equations of a large number of variables. Moreover, the author presents a wide range of problem sets and their solutions. The target audience primarily comprises advanced undergraduate and graduate students of mechanical and civil engineering, but the book may also be beneficial for practising engineers in industry.

  12. Specific elements in the functional structure of Ljubljane

    Directory of Open Access Journals (Sweden)

    Mirko Pak


    Full Text Available The functional structure of Ljubljana is predominated by supply activities which form its own new city network. Particular attention shall be paid to four big supply centres and the interdependence of their development with the commercial function within the city centre. This has also been confirmed on the basis of the results of a questionnaire, with the reasons for the development processes pointed out, which are in favour of the big trade centres in Šiška, Moste, Rakovnik and Vič.

  13. Finite Element Modeling of Acoustic Shielding via Phononic Crystal structures


    Lipp, Clémentine Sophie Sarah; Lozzi, Andrea


    Quality factor of Contour Mode Resonators (CMR) are mainly affected by energy losses due to acoustic waves leaving the resonator through the anchors. An engineering of the anchors in order to create a periodic variation in the acoustic impedance of the material, structures known as Phononic Crystals (PnCs), can help improve the Q factor by reflecting part of the acoustic waves. During this project, FEM models have been validated for both 1D and 2D PnCs. The behavior of the band diagram and qu...

  14. G-quadruplex structures within the 3' UTR of LINE-1 elements stimulate retrotransposition. (United States)

    Sahakyan, Aleksandr B; Murat, Pierre; Mayer, Clemens; Balasubramanian, Shankar


    Long interspersed nuclear elements (LINEs) are ubiquitous transposable elements in higher eukaryotes that have a significant role in shaping genomes, owing to their abundance. Here we report that guanine-rich sequences in the 3' untranslated regions (UTRs) of hominoid-specific LINE-1 elements are coupled with retrotransposon speciation and contribute to retrotransposition through the formation of G-quadruplex (G4) structures. We demonstrate that stabilization of the G4 motif of a human-specific LINE-1 element by small-molecule ligands stimulates retrotransposition.

  15. Development of a finite dynamic element for free vibration analysis of two-dimensional structures (United States)

    Gupta, K. K.


    The paper develops an efficient free-vibration analysis procedure of two-dimensional structures. This is achieved by employing a discretization technique based on a recently developed concept of finite dynamic elements, involving higher order dynamic correction terms in the associated stiffness and inertia matrices. A plane rectangular dynamic element is developed in detail. Numerical solution results of free-vibration analysis presented herein clearly indicate that these dynamic elements combined with a suitable quadratic matrix eigenproblem solution technique effect a most economical and efficient solution for such an analysis when compared with the usual finite element method.

  16. Structured Extended Finite Element Methods of Solids Defined by Implicit Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Belytschko, T; Mish, K; Moes, N; Parimi, C


    A paradigm is developed for generating structured finite element models from solid models by means of implicit surface definitions. The implicit surfaces are defined by radial basis functions. Internal features, such as material interfaces, sliding interfaces and cracks are treated by enrichment techniques developed in the extended finite element method (X-FEM). Methods for integrating the weak form for such models are proposed. These methods simplify the generation of finite element models. Results presented for several examples show that the accuracy of this method is comparable to standard unstructured finite element methods.

  17. Structural elements of construction of individual and group exercises’ competition compositions in calisthenics

    Directory of Open Access Journals (Sweden)

    Y.O. Kovalenko


    Full Text Available Purpose: to analyze content of individual and group exercises’ competition compositions in calisthenics. Material: in the research HEEs’ girl students (n=20, junior sportswomen (n=10, experts (n=30, coaches with 10-40 years’ working experience participated. Results: it was found that temporary indicators permit to assess level of female gymnasts’ readiness for fulfillment of competition compositions’ elements; facilitated rational correlation of body and object’s elements of complexity. Quickness of preparation to elements and directly time of exercise’s fulfillment acquire great importance. In individual and group exercises the most important are distribution of sportswoman’s moving on all site with frequent change of directions. It was established that realization of structural elements facilitates full opening of female gymnast’s artistic image. Conclusions: for building of competition compositions coaches shall fully use indicators of space and time structural elements.

  18. Efficient Analysis of Structures with Rotatable Elements Using Model Order Reduction

    Directory of Open Access Journals (Sweden)

    G. Fotyga


    Full Text Available This paper presents a novel full-wave technique which allows for a fast 3D finite element analysis of waveguide structures containing rotatable tuning elements of arbitrary shapes. Rotation of these elements changes the resonant frequencies of the structure, which can be used in the tuning process to obtain the S-characteristics desired for the device. For fast commutations of the response as the tuning elements are rotated, the 3D finite element method is supported by multilevel model-order reduction, orthogonal projection at the boundaries of macromodels and the operation called macromodels cloning. All the time-consuming steps are performed only once in the preparatory stage. In the tuning stage, only small parts of the domain are updated, by means of a special meshing technique. In effect, the tuning process is performed extremely rapidly. The results of the numerical experiments confirm the efficiency and validity of the proposed method.

  19. STARS: A general-purpose finite element computer program for analysis of engineering structures (United States)

    Gupta, K. K.


    STARS (Structural Analysis Routines) is primarily an interactive, graphics-oriented, finite-element computer program for analyzing the static, stability, free vibration, and dynamic responses of damped and undamped structures, including rotating systems. The element library consists of one-dimensional (1-D) line elements, two-dimensional (2-D) triangular and quadrilateral shell elements, and three-dimensional (3-D) tetrahedral and hexahedral solid elements. These elements enable the solution of structural problems that include truss, beam, space frame, plane, plate, shell, and solid structures, or any combination thereof. Zero, finite, and interdependent deflection boundary conditions can be implemented by the program. The associated dynamic response analysis capability provides for initial deformation and velocity inputs, whereas the transient excitation may be either forces or accelerations. An effective in-core or out-of-core solution strategy is automatically employed by the program, depending on the size of the problem. Data input may be at random within a data set, and the program offers certain automatic data-generation features. Input data are formatted as an optimal combination of free and fixed formats. Interactive graphics capabilities enable convenient display of nodal deformations, mode shapes, and element stresses.

  20. Structural elements regulating amyloidogenesis: a cholinesterase model system.

    Directory of Open Access Journals (Sweden)

    Létitia Jean


    Full Text Available Polymerization into amyloid fibrils is a crucial step in the pathogenesis of neurodegenerative syndromes. Amyloid assembly is governed by properties of the sequence backbone and specific side-chain interactions, since fibrils from unrelated sequences possess similar structures and morphologies. Therefore, characterization of the structural determinants driving amyloid aggregation is of fundamental importance. We investigated the forces involved in the amyloid assembly of a model peptide derived from the oligomerization domain of acetylcholinesterase (AChE, AChE(586-599, through the effect of single point mutations on beta-sheet propensity, conformation, fibrilization, surfactant activity, oligomerization and fibril morphology. AChE(586-599 was chosen due to its fibrilization tractability and AChE involvement in Alzheimer's disease. The results revealed how specific regions and residues can control AChE(586-599 assembly. Hydrophobic and/or aromatic residues were crucial for maintaining a high beta-strand propensity, for the conformational transition to beta-sheet, and for the first stage of aggregation. We also demonstrated that positively charged side-chains might be involved in electrostatic interactions, which could control the transition to beta-sheet, the oligomerization and assembly stability. Further interactions were also found to participate in the assembly. We showed that some residues were important for AChE(586-599 surfactant activity and that amyloid assembly might preferentially occur at an air-water interface. Consistently with the experimental observations and assembly models for other amyloid systems, we propose a model for AChE(586-599 assembly in which a steric-zipper formed through specific interactions (hydrophobic, electrostatic, cation-pi, SH-aromatic, metal chelation and polar-polar would maintain the beta-sheets together. We also propose that the stacking between the strands in the beta-sheets along the fiber axis could

  1. Finite Element Analysis for Satellite Structures Applications to Their Design, Manufacture and Testing

    CERN Document Server

    Abdelal, Gasser F; Gad, Ahmed H


    Designing satellite structures poses an ongoing challenge as the interaction between analysis, experimental testing, and manufacturing phases is underdeveloped. Finite Element Analysis for Satellite Structures: Applications to Their Design, Manufacture and Testing explains the theoretical and practical knowledge needed to perform design of satellite structures. By layering detailed practical discussions with fully developed examples, Finite Element Analysis for Satellite Structures: Applications to Their Design, Manufacture and Testing provides the missing link between theory and implementation.   Computational examples cover all the major aspects of advanced analysis; including modal analysis, harmonic analysis, mechanical and thermal fatigue analysis using finite element method. Test cases are included to support explanations an a range of different manufacturing simulation techniques are described from riveting to shot peening to material cutting. Mechanical design of a satellites structures are covered...

  2. Sequence and structure-specific elements of HERG mRNA determine channel synthesis and trafficking efficiency (United States)

    Sroubek, Jakub; Krishnan, Yamini; McDonald, Thomas V.


    Human ether-á-gogo-related gene (HERG) encodes a potassium channel that is highly susceptible to deleterious mutations resulting in susceptibility to fatal cardiac arrhythmias. Most mutations adversely affect HERG channel assembly and trafficking. Why the channel is so vulnerable to missense mutations is not well understood. Since nothing is known of how mRNA structural elements factor in channel processing, we synthesized a codon-modified HERG cDNA (HERG-CM) where the codons were synonymously changed to reduce GC content, secondary structure, and rare codon usage. HERG-CM produced typical IKr-like currents; however, channel synthesis and processing were markedly different. Translation efficiency was reduced for HERG-CM, as determined by heterologous expression, in vitro translation, and polysomal profiling. Trafficking efficiency to the cell surface was greatly enhanced, as assayed by immunofluorescence, subcellular fractionation, and surface labeling. Chimeras of HERG-NT/CM indicated that trafficking efficiency was largely dependent on 5′ sequences, while translation efficiency involved multiple areas. These results suggest that HERG translation and trafficking rates are independently governed by noncoding information in various regions of the mRNA molecule. Noncoding information embedded within the mRNA may play a role in the pathogenesis of hereditary arrhythmia syndromes and could provide an avenue for targeted therapeutics.—Sroubek, J., Krishnan, Y., McDonald, T V. Sequence- and structure-specific elements of HERG mRNA determine channel synthesis and trafficking efficiency. PMID:23608144

  3. Effect of Large Negative Phase of Blast Loading on Structural Response of RC Elements

    Directory of Open Access Journals (Sweden)

    Syed Zubair Iman


    Full Text Available Structural response of reinforced concrete (RC elements for analysis and design are often obtained using the positive phase of the blast pressure curve disregarding the negative phase assuming insignificant contribution from the negative phase of the loading. Although, some insight on the effect of negative phase of blast pressure based on elastic single-degree-of-freedom (SDOF analysis was presented before, the influence of negative phase on different types of resistance functions of SDOF models and on realistic finite element analysis has not been explored. In this study, the effects of inclusion of pulse negative phase on structural response of RC elements from SDOF analysis and from more detailed finite element analysis have been investigated. Investigation of SDOF part has been conducted using MATLAB code that utilizes non-linear resistance functions of SDOF model. Detailed numerical investigation using finite element code DIANA was conducted on the significance of the negative phase on structural response. In the FE model, different support stiffness was used to explore the effect of support stiffness on the structural response due to blast negative phase. Results from SDOF and FE analyses present specific situations where the effect of large negative phase was found to be significant on the structural response of RC elements.

  4. Structure of Hybrid Interpolymeric Complexes of Polyvinyl Alcohol and Halides of Second Group Elements

    Directory of Open Access Journals (Sweden)

    I. Yu. Prosanov


    Full Text Available Density functional theory was used to investigate structure and properties of polyvinyl alcohol complexes with halides of second group elements XHal2 (X = Be, Mg, Ca, Zn, Sr, Cd, Ba, and Hg; Hal = F, Cl, Br, and I. PVA can form hybrid interpolymeric complexes with some of them. These complexes show double spiral structure of two types.

  5. Structural and Economic Viability of 2D/3D Finite Element Analysis ...

    African Journals Online (AJOL)

    Consequently, this paper examines the structural and economic viability of arched conical roof truss system based on 2D/3D finite element method analysis. Analysis of the results showed that truss members were subjected to higher axial forces in 2D analysis than 3D analysis, which will result to overdesign of the structural ...

  6. Finite element based electrostatic-structural coupled analysis with automated mesh morphing

    Energy Technology Data Exchange (ETDEWEB)



    A co-simulation tool based on finite element principles has been developed to solve coupled electrostatic-structural problems. An automated mesh morphing algorithm has been employed to update the field mesh after structural deformation. The co-simulation tool has been successfully applied to the hysteric behavior of a MEMS switch.

  7. In Vitro Biocompatibility of Si Alloyed Multi-Principal Element Carbide Coatings.

    Directory of Open Access Journals (Sweden)

    Alina Vladescu

    Full Text Available In the current study, we have examined the possibility to improve the biocompatibility of the (TiZrNbTaHfC through replacement of either Ti or Ta by Si. The coatings were deposited on Si and 316L stainless steel substrates by magnetron sputtering in an Ar+CH4 mixed atmosphere and were examined for elemental composition, chemical bonds, surface topography, surface electrical charge and biocompatible characteristics. The net surface charge was evaluated at nano and macroscopic scale by measuring the electrical potential and work function, respectively. The biocompatible tests comprised determination of cell viability and cell attachment to the coated surface. The deposited coatings had C/(metal+Si ratios close to unity, while a mixture of metallic carbide, free-carbon and oxidized species formed on the film surface. The coatings' surfaces were smooth and no influence of surface roughness on electrical charge or biocompatibility was found. The biocompatible characteristics correlated well with the electrical potential/work function, suggesting a significant role of surface charge in improving biocompatibility, particularly cell attachment to coating's surface. Replacement of either Ti or Ta by Si in the (TiZrNbTaHfC coating led to an enhanced surface electrical charge, as well as to superior biocompatible properties, with best results for the (TiZrNbSiHfC coating.

  8. Molecules and Models The molecular structures of main group element compounds

    CERN Document Server

    Haaland, Arne


    This book provides a systematic description of the molecular structures and bonding in simple compounds of the main group elements with particular emphasis on bond distances, bond energies and coordination geometries. The description includes the structures of hydrogen, halogen and methyl derivatives of the elements in each group, some of these molecules are ionic, some polar covalent. The survey of molecules whose structures conform to well-established trends is followed byrepresentative examples of molecules that do not conform. We also describe electron donor-acceptor and hydrogen bonded co

  9. Finite Element Approach for Analyses of Flanking Noise Transmission within Lightweight Panel Structure

    DEFF Research Database (Denmark)

    Domadiya, Parthkumar Gandalal; Dickow, Kristoffer Ahrens; Andersen, Lars


    This paper concerns the analysis of noise transmission in a lightweight panel structure. The analysis is based on Finite Element Analysis (FEA) employing solid elements for the structure. The analysis focuses on flanking noise transmission in panel structures of finite size. A parametric study...... and different designs of the ribs regarding the energy contained within the panel strip. The paper presents an analysis of vibrational energy transmission for an isotropic periodic panel strip excited by a concentrated force. The computations are carried out in frequency domain in the range below 2 kHz....

  10. Adaptive Crack Modeling with Interface Solid Elements for Plain and Fiber Reinforced Concrete Structures. (United States)

    Zhan, Yijian; Meschke, Günther


    The effective analysis of the nonlinear behavior of cement-based engineering structures not only demands physically-reliable models, but also computationally-efficient algorithms. Based on a continuum interface element formulation that is suitable to capture complex cracking phenomena in concrete materials and structures, an adaptive mesh processing technique is proposed for computational simulations of plain and fiber-reinforced concrete structures to progressively disintegrate the initial finite element mesh and to add degenerated solid elements into the interfacial gaps. In comparison with the implementation where the entire mesh is processed prior to the computation, the proposed adaptive cracking model allows simulating the failure behavior of plain and fiber-reinforced concrete structures with remarkably reduced computational expense.

  11. Adaptive Crack Modeling with Interface Solid Elements for Plain and Fiber Reinforced Concrete Structures (United States)

    Zhan, Yijian


    The effective analysis of the nonlinear behavior of cement-based engineering structures not only demands physically-reliable models, but also computationally-efficient algorithms. Based on a continuum interface element formulation that is suitable to capture complex cracking phenomena in concrete materials and structures, an adaptive mesh processing technique is proposed for computational simulations of plain and fiber-reinforced concrete structures to progressively disintegrate the initial finite element mesh and to add degenerated solid elements into the interfacial gaps. In comparison with the implementation where the entire mesh is processed prior to the computation, the proposed adaptive cracking model allows simulating the failure behavior of plain and fiber-reinforced concrete structures with remarkably reduced computational expense. PMID:28773130

  12. Finite element model updating of concrete structures based on imprecise probability (United States)

    Biswal, S.; Ramaswamy, A.


    Imprecise probability based methods are developed in this study for the parameter estimation, in finite element model updating for concrete structures, when the measurements are imprecisely defined. Bayesian analysis using Metropolis Hastings algorithm for parameter estimation is generalized to incorporate the imprecision present in the prior distribution, in the likelihood function, and in the measured responses. Three different cases are considered (i) imprecision is present in the prior distribution and in the measurements only, (ii) imprecision is present in the parameters of the finite element model and in the measurement only, and (iii) imprecision is present in the prior distribution, in the parameters of the finite element model, and in the measurements. Procedures are also developed for integrating the imprecision in the parameters of the finite element model, in the finite element software Abaqus. The proposed methods are then verified against reinforced concrete beams and prestressed concrete beams tested in our laboratory as part of this study.

  13. Optimal Layout Design using the Element Connectivity Parameterization Method: Application to Three Dimensional Geometrical Nonlinear Structures

    DEFF Research Database (Denmark)

    Yoon, Gil Ho; Joung, Young Soo; Kim, Yoon Young


    of freedom of the element-connectivity parameterizing links are eliminated in element level before the total system matrix is assembled. In terms of implementation, however, the E-ECP is easier to use because the sensitivity analysis in E-ECP does not require the explicit expression of the (tangent......The topology design optimization of “three-dimensional geometrically-nonlinear” continuum structures is still a difficult problem not only because of its problem size but also the occurrence of unstable continuum finite elements during the design optimization. To overcome this difficulty......) stiffness matrix of continuum finite elements. Therefore, any finite element code, including commercial codes, can be readily used for the ECP implementation. The key ideas and characteristics of these methods will be presented in this paper....

  14. Challenges in Integrating Nondestructive Evaluation and Finite Element Methods for Realistic Structural Analysis (United States)

    Abdul-Aziz, Ali; Baaklini, George Y.; Zagidulin, Dmitri; Rauser, Richard W.


    Capabilities and expertise related to the development of links between nondestructive evaluation (NDE) and finite element analysis (FEA) at Glenn Research Center (GRC) are demonstrated. Current tools to analyze data produced by computed tomography (CT) scans are exercised to help assess the damage state in high temperature structural composite materials. A utility translator was written to convert velocity (an image processing software) STL data file to a suitable CAD-FEA type file. Finite element analyses are carried out with MARC, a commercial nonlinear finite element code, and the analytical results are discussed. Modeling was established by building MSC/Patran (a pre and post processing finite element package) generated model and comparing it to a model generated by Velocity in conjunction with MSC/Patran Graphics. Modeling issues and results are discussed in this paper. The entire process that outlines the tie between the data extracted via NDE and the finite element modeling and analysis is fully described.

  15. Assessment of Structural Behavior of Non-corroded and Corroded RCC Beams Using Finite Element Method

    Directory of Open Access Journals (Sweden)

    Anand Parande


    Full Text Available A three dimensional finite element model is developed to examine the structural behaviour of corroded reinforced concrete beam and non corroded reinforced concrete beam. Non linear finite element analysis is performed using the ANSYS program. SOLID 65, LINK 8 element represent concrete and discrete reinforcing steel bars, based on each component actual characteristics, non linear material properties are defined for both elements. The effect of corrosion in reinforced concrete is studied by finite element analysis; an approach is developed to model the corrosion product expansion causing concrete cover cracking for this, beam has been modeled using ANSYS and using this data the beam has been casted with M20 concrete after 28 days the beam will be tested for flexural strength. The comparison between ANSYS prediction and field data are made in terms of deflection, stress, strain, bond strength and crack pattern of concrete beam.

  16. Development of Practical Finite Element Models for Collapse of Reinforced Concrete Structures and Experimental Validation

    Directory of Open Access Journals (Sweden)

    Mario Bermejo


    Full Text Available This paper describes two practical methodologies for modeling the collapse of reinforced concrete structures. They are validated with a real scale test of a two-floor structure which loses a bearing column. The objective is to achieve accurate simulations of collapse phenomena with moderate computational cost. Explicit finite element models are used with Lagrangian meshes, modeling concrete, and steel in a segregated manner. The first model uses 3D continuum finite elements for concrete and beams for steel bars, connected for displacement compatibility using a penalty method. The second model uses structural finite elements, shells for concrete, and beams for steel, connected in common nodes with an eccentricity formulation. Both are capable of simulating correctly the global behavior of the structural collapse. The continuum finite element model is more accurate for interpreting local failure but has an excessive computational cost for a complete building. The structural finite element model proposed has a moderate computational cost, yields sufficiently accurate results, and as a result is the recommended methodology.

  17. Structural analysis of composite wind turbine blades nonlinear mechanics and finite element models with material damping

    CERN Document Server

    Chortis, Dimitris I


    This book concerns the development of novel finite elements for the structural analysis of composite beams and blades. The introduction of material damping is also an important aspect of composite structures and it is presented here in terms of their static and dynamic behavior. The book thoroughly presents a new shear beam finite element, which entails new blade section mechanics, capable of predicting structural blade coupling due to composite coupling and/or internal section geometry. Theoretical background is further expanded towards the inclusion of nonlinear structural blade models and damping mechanics for composite structures. The models effectively include geometrically nonlinear terms due to large displacements and rotations, improve the modeling accuracy of very large flexible blades, and enable the modeling of rotational stiffening and buckling, as well as, nonlinear structural coupling. Validation simulations on specimen level study the geometric nonlinearities effect on the modal frequencies and...

  18. Adaptive Finite Element Technology in Integrated Design and Analysis. [aircraft structures design (United States)

    Szabo, B. A.; Basu, P. K.; Dunavant, D. A.; Vasilopoulos, D.


    An assessment of the potential impact of adaptive finite element technology on the analysis part of the aircraft structural synthesis process is presented. The main conclusion is that adaptive application of the p-version of the finite element method based on indirect error estimation procedures results in substantial cost reduction and increased reliability of the computed data. Adaptivity based on direct a posteriori error estimation has the potential for additional savings.

  19. Parameterized Automated Generic Model for Aircraft Wing Structural Design and Mesh Generation for Finite Element Analysis


    Sohaib, Muhammad


    This master thesis work presents the development of a parameterized automated generic model for the structural design of an aircraft wing. Furthermore, in order to perform finite element analysis on the aircraft wing geometry, the process of finite element mesh generation is automated. Aircraft conceptual design is inherently a multi-disciplinary design process which involves a large number of disciplines and expertise. In this thesis work, it is investigated how high-end CAD software‟s can b...

  20. Stochastic Finite Element Analysis of Non-Linear Structures Modelled by Plasticity Theory

    DEFF Research Database (Denmark)

    Frier, Christian; Sørensen, John Dalsgaard


    A Finite Element Reliability Method (FERM) is introduced to perform reliability analyses on two-dimensional structures in plane stress, modeled by non-linear plasticity theory. FERM is a coupling between the First Order Reliability Method (FORM) and the Finite Element Method (FEM). FERM can be used...... Method (DDM), here adapted to work with a generally formulated plasticity based constitutive model. The approach is exemplified with a steel plate with a hole in bending subjected to a displacement based limit state function....

  1. In vitro radio autographic studies of the biodistribution of radiopharmaceuticals on blood elements

    Energy Technology Data Exchange (ETDEWEB)

    Eipoll-Hamer, E.; De Paula, E.F. [Instituto Nacional do Cancer, Rio de Janeiro, RJ (Brazil). Centro de Pesquisa Basica; Freitas, L.C. [Instituto Nacional do Cancer, Rio de Janeiro, RJ (Brazil). Servico de Quimioterapia; Pereira, M.J.S.; Carvalho, J.J.; Porto, L.C.M.S. [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Dept. de Histologia e Embriologi; Fonseca, L.M. [Instituto Nacional do Cancer, Rio de Janeiro, RJ (Brazil). Servico de Medicina Nuclear; Gutfilen, B.; Bernardo Filho, M. [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Inst. de Biofisica e Biometria


    In the present study we evaluated the binding of the radiopharmaceuticals sodium pertechnetate (Na{sup 99m} Tc O{sub 4}), methylene-diphosphonic acid ({sup 99m} Tc-M D P) and glucoheptonate acid ({sup 99m} Tc-G H A) to blood elements using centrifugation and radio autographic techniques. Heparinized blood was incubated with the labelled compounds for 0,1,2,3,4, 6 and 24 h. Plasma (P) and blood cells (B C) were isolated and precipitated with 5% trichloroacetic acid (TCA), and soluble (S F) and insoluble fractions (IF) were separated. Blood samples were prepared (0 and 24 h) and coated with Lm-1 radio autographic emulsions and percent radioactivity (%rad) in P and B C was determined. The binding of Na{sup 99m} Tc O{sub 4} (5 rad) to P was 61.2 (0 h) and 46.0% (24 h), and radioautography showed 63.7% (0 h) and 43.3% (24 h). The binding to B C was 38.8% (0 h) and 54.0% (24 h), and radioautography showed 36.3% (0 h) and 56.7% (24 h). {sup 99m} Tc-M D P study presented 91.1% (0 h) to P and 87.2%(24 h), and radioautography showed presented 91.1% (0 h) to P and 87.2% (24 h), and radioautography showed 67.9% (0 h) and 67.4% (24 h). The binding to B C was 8.9% (0 h) and 12.8% (24 h), and radioautography showed 32.1% (0 h) and 32.6% (24 h). {sup 99m} Tc-G H A study was 90.1% (0 h) to P and 79.9% (24 h), and radioautography showed 67.2% (0 h) and 60.1% (24 h). The binding to B C was 9.9% (0 h) and 20.1% (24 h), and radioautography showed 32.8% (0 h) and 39.9% (24 h). The comparison of the obtained results suggests that the binding to plasma and blood cells in the two techniques used (radioautography and centrifugation) is qualitatively in accordance. (author) 20 refs., 2 tabs.

  2. In vitro radioautographic studies of the biodistribution of radiopharmaceuticals on blood elements

    Directory of Open Access Journals (Sweden)

    Ripoll-Hamer E.


    Full Text Available In the present study we evaluated the binding of the radiopharmaceuticals sodium pertechnetate (Na 99mTcO4, methylenediphosphonic acid (99mTc-MDP and glucoheptonate acid (99mTc-GHA to blood elements using centrifugation and radioautographic techniques. Heparinized blood was incubated with the labelled compounds for 0, 1, 2, 3, 4, 6 and 24 h. Plasma (P and blood cells (BC were isolated and precipitated with 5% trichloroacetic acid (TCA, and soluble (SF and insoluble fractions (IF were separated. Blood samples were prepared (0 and 24 h and coated with LM-1 radioautographic emulsions and percent radioactivity (%rad in P and BC was determined. The binding of Na 99mTcO4 (%rad to P was 61.2% (0 h and 46.0% (24 h, and radioautography showed 63.7% (0 h and 43.3% (24 h. The binding to BC was 38.8% (0 h and 54.0% (24 h, and radioautography showed 36.3% (0 h and 56.7% (24 h. 99mTc-MDP study presented 91.1% (0 h to P and 87.2% (24 h, and radioautography showed 67.9% (0 h and 67.4% (24 h. The binding to BC was 8.9% (0 h and 12.8% (24 h, and radioautography showed 32.1% (0 h and 32.6% (24 h. 99mTc-GHA study was 90.1% (0 h to P and 79.9% (24 h, and radioautography showed 67.2% (0 h and 60.1% (24 h. The binding to BC was 9.9% (0 h and 20.1% (24 h, and radioautography showed 32.8% (0 h and 39.9% (24 h. The comparison of the obtained results suggests that the binding to plasma and blood cells in the two techniques used (radioautography and centrifugation is qualitatively in accordance

  3. On a finite dynamic element method for free vibration analysis of structures (United States)

    Gupta, K. K.


    This paper explores the concept of finite dynamic elements involving higher order dynamic correction terms in the associated stiffness and mass matrices. Such matrices are then developed for a rectangular prestressed membrane element. Next, efficient analysis techniques for the eigenproblem solution of the resulting quadratic matrix equations are described in detail. These are followed by suitable numerical examples which indicate that employment of such dynamic elements in conjunction with an efficient quadratic matric solution technique will result in a most significant economy in the free vibration analysis of structures.

  4. Finite-element based perturbation analysis of wave propagation in nonlinear periodic structures (United States)

    Manktelow, Kevin; Narisetti, Raj K.; Leamy, Michael J.; Ruzzene, Massimo


    Wave propagation in continuous, periodic structures subject to weak nonlinearities is studied using a finite-element discretization of a single unit cell followed by a perturbation analysis. The dispersion analysis is integrated with commercial finite-element analysis (FEA) software to expedite nonlinear analysis of geometrically-complex unit cells. A simple continuous multilayer system is used to illustrate the principle aspects of the procedure. A periodic structure formed by membrane elements on nonlinear elastic supports is used to demonstrate the versatility of the procedure. Weakly nonlinear band diagrams are generated in which amplitude-dependent bandgaps and group velocities are identified. The nonlinear dispersion analysis procedure described, coupled with commercial FEA software, should facilitate the study of wave propagation in a wide-variety of geometrically-complex, nonlinear periodic structures.

  5. Shape and Stress Sensing of Multilayered Composite and Sandwich Structures Using an Inverse Finite Element Method (United States)

    Cerracchio, Priscilla; Gherlone, Marco; Di Sciuva, Marco; Tessler, Alexander


    The marked increase in the use of composite and sandwich material systems in aerospace, civil, and marine structures leads to the need for integrated Structural Health Management systems. A key capability to enable such systems is the real-time reconstruction of structural deformations, stresses, and failure criteria that are inferred from in-situ, discrete-location strain measurements. This technology is commonly referred to as shape- and stress-sensing. Presented herein is a computationally efficient shape- and stress-sensing methodology that is ideally suited for applications to laminated composite and sandwich structures. The new approach employs the inverse Finite Element Method (iFEM) as a general framework and the Refined Zigzag Theory (RZT) as the underlying plate theory. A three-node inverse plate finite element is formulated. The element formulation enables robust and efficient modeling of plate structures instrumented with strain sensors that have arbitrary positions. The methodology leads to a set of linear algebraic equations that are solved efficiently for the unknown nodal displacements. These displacements are then used at the finite element level to compute full-field strains, stresses, and failure criteria that are in turn used to assess structural integrity. Numerical results for multilayered, highly heterogeneous laminates demonstrate the unique capability of this new formulation for shape- and stress-sensing.

  6. Dynamic Shape Reconstruction of Three-Dimensional Frame Structures Using the Inverse Finite Element Method (United States)

    Gherlone, Marco; Cerracchio, Priscilla; Mattone, Massimiliano; Di Sciuva, Marco; Tessler, Alexander


    A robust and efficient computational method for reconstructing the three-dimensional displacement field of truss, beam, and frame structures, using measured surface-strain data, is presented. Known as shape sensing , this inverse problem has important implications for real-time actuation and control of smart structures, and for monitoring of structural integrity. The present formulation, based on the inverse Finite Element Method (iFEM), uses a least-squares variational principle involving strain measures of Timoshenko theory for stretching, torsion, bending, and transverse shear. Two inverse-frame finite elements are derived using interdependent interpolations whose interior degrees-of-freedom are condensed out at the element level. In addition, relationships between the order of kinematic-element interpolations and the number of required strain gauges are established. As an example problem, a thin-walled, circular cross-section cantilevered beam subjected to harmonic excitations in the presence of structural damping is modeled using iFEM; where, to simulate strain-gauge values and to provide reference displacements, a high-fidelity MSC/NASTRAN shell finite element model is used. Examples of low and high-frequency dynamic motion are analyzed and the solution accuracy examined with respect to various levels of discretization and the number of strain gauges.

  7. Structural Health Monitoring Using High-Density Fiber Optic Strain Sensor and Inverse Finite Element Methods (United States)

    Vazquez, Sixto L.; Tessler, Alexander; Quach, Cuong C.; Cooper, Eric G.; Parks, Jeffrey; Spangler, Jan L.


    In an effort to mitigate accidents due to system and component failure, NASA s Aviation Safety has partnered with industry, academia, and other governmental organizations to develop real-time, on-board monitoring capabilities and system performance models for early detection of airframe structure degradation. NASA Langley is investigating a structural health monitoring capability that uses a distributed fiber optic strain system and an inverse finite element method for measuring and modeling structural deformations. This report describes the constituent systems that enable this structural monitoring function and discusses results from laboratory tests using the fiber strain sensor system and the inverse finite element method to demonstrate structural deformation estimation on an instrumented test article


    Directory of Open Access Journals (Sweden)

    Stefano Valvano


    Full Text Available In this paper a new plate finite element (FE for the analysis of composite and sandwich plates is proposed. By making use of the node-variable plate theory assumptions, the new finite element allows for a simultaneous analysis of different subregions of the problem domain with different kinematics and accuracy, in a global/local sense. In particular higher-order theories with an Equivalent-Single-Layer (ESL approach are simultaneously used with advanced Layer-Wise (LW models. As a consequence, the computational costs can be reduced drastically by assuming refined theories only in those zones/nodes of the structural domain where the resulting strain and stress states present a complex distribution. On the contrary, computationally cheaper, low-order kinematic assumptions can be used in the remaining parts of the plate where a localized detailed analysis is not necessary. The primary advantage of the present variable-kinematics element and related global/local approach is that no ad-hoc techniques and mathematical artifices are required to mix the fields coming from two different and kinematically incompatible adjacent elements, because the plate structural theory varies within the finite element itself. In other words, the structural theory of the plate element is a property of the FE node in this present approach, and the continuity between two adjacent elements is ensured by adopting the same kinematics at the interface nodes. According to the Unified Formulation by Carrera, the through-the-thickness unknowns are described by Taylor polynomial expansions with ESL approach and by Legendre polynomials with LW approach. Furthermore, the Mixed Interpolated Tensorial Components (MITC method is employed to contrast the shear locking phenomenon. Several numerical investigations are carried out to validate and demonstrate the accuracy and efficiency of the present plate element, including comparison with various closed-form and FE solutions from the

  9. [Effects of rare earth elements on soil fauna community structure and their ecotoxicity to Holotrichia parallela]. (United States)

    Li, Guiting; Jiang, Junqi; Chen, Jie; Zou, Yunding; Zhang, Xincai


    By the method of OECD filter paper contact, this paper studied the effects of applied rare earth elements on soil fauna community structure and their ecological toxicity to Holotrichia parallela in bean field. The results showed that there were no significant differences between the treatments and the control in soil fauna species, quantity of main species, and diversity index. Urgent and chronic toxic test showed that the differences between the treatments and the control were not significant. It was suggested that within the range of test dosages, rare earth elements had little ecological toxicity to Holotrichia parallela, and did not change the soil fauna community structure.

  10. Applications of a global nuclear-structure model to studies of the heaviest elements

    Energy Technology Data Exchange (ETDEWEB)

    Moeller, P.; Nix, J.R.


    We present some new results on heavy-element nuclear-structure properties calculated on the basis of the finite-range droplet model and folded-Yukawa single-particle potential. Specifically, we discuss calculations of nuclear ground-state masses and microscopic corrections, {alpha}-decay properties, {beta}-decay properties, fission potential-energy surfaces, and spontaneous-fission half-lives. These results, obtained in a global nuclear-structure approach, are particularly reliable for describing the stability properties of the heaviest elements.

  11. Performance assessment of geotechnical structural elements using distributed fiber optic sensing (United States)

    Monsberger, Christoph; Woschitz, Helmut; Lienhart, Werner; Račanský, Václav; Hayden, Martin


    Geotechnical structural elements are used to underpin heavy structures or to stabilize slopes and embankments. The bearing capacity of these components is usually verified by geotechnical load tests. It is state of the art to measure the resulting deformations with electronic sensors at the surface and therefore, the load distribution along the objects cannot be determined. This paper reports about distributed strain measurements with an optical backscatter reflectometer along geotechnical elements. In addition to the installation of the optical fiber in harsh field conditions, results of investigations of the fiber optic system in the laboratory and the most significant results of the field trials are presented.

  12. Dynamic thermal wave response and propagation through building structures using infinite elements in time and frequency domain (United States)

    Kazakov, Konstantin S.; Stoynova, Iliana Y.


    This paper is devoted to a new approach the dynamic termal response and the factor of termal wave propagation through of complex building structure to be evaluated using infinite elements. The far field of such structures is discretized by decay or mapped infinite elements. These elements are appropriate for complex building structures, subjected to termal wave propagation and solved in time or frequency domain. Such infinite elements can be treated as new modified forms of the recently proposed by the first author infinite elements with united shape functions. In the research the time domain form of the equations is demonstrated and used in the numerical example. Only 2D horizontal type infinite elements is used, but by similar techniques 2D vertical and 2D corner infinite elements can also be formulated. The application of the proposed elements in the Finite element method is demonstrated in brief.

  13. On location of piezoelectric element in a smart-structure: numerical investigation and experiment (United States)

    Oshmarin, D.; Iurlov, M.


    In this paper, based on some example problems it was demonstrated that in examining the possibilities of smart structure applications, the matter of considerable researchers’ concern is the problem of location of piezoelectric elements in the structure to allow effective realization of its smart functions in the framework of the specified strategy of structure control and target purposes (vibration damping, defectoscopy, etc.) The numerical and experimental investigations have shown that for structures with the elements made of piezoelectric materials, it is more convenient to use as a parameter, specifying the best location of the piezoelectric element for damping the vibrations at the prescribed frequency, the coefficient of electromechanical coupling, which is evaluated by the values of eigenfrequencies of the structure in the short-circuit and open-circuit regimes. The values of eigenfrequencies of vibrations are evaluated by solving the problem of natural vibrations of electromechanical systems by the finite element method using the applied ANSYS package. The investigation were conducted for a thin-walled aluminum shell in the form of half-cylinder.

  14. Creating a Test-Validated Finite-Element Model of the X-56A Aircraft Structure (United States)

    Pak, Chan-Gi; Truong, Samson


    Small modeling errors in a finite-element model will eventually induce errors in the structural flexibility and mass, thus propagating into unpredictable errors in the unsteady aerodynamics and the control law design. One of the primary objectives of the X-56A Multi-Utility Technology Testbed aircraft is the flight demonstration of active flutter suppression and, therefore, in this study, the identification of the primary and secondary modes for the structural model tuning based on the flutter analysis of the X-56A aircraft. The ground-vibration test-validated structural dynamic finite-element model of the X-56A aircraft is created in this study. The structural dynamic finite-element model of the X-56A aircraft is improved using a model-tuning tool. In this study, two different weight configurations of the X-56A aircraft have been improved in a single optimization run. Frequency and the cross-orthogonality (mode shape) matrix were the primary focus for improvement, whereas other properties such as c.g. location, total weight, and off-diagonal terms of the mass orthogonality matrix were used as constraints. The end result was an improved structural dynamic finite-element model configuration for the X-56A aircraft. Improved frequencies and mode shapes in this study increased average flutter speeds of the X-56A aircraft by 7.6% compared to the baseline model.

  15. Creating a Test Validated Structural Dynamic Finite Element Model of the X-56A Aircraft (United States)

    Pak, Chan-Gi; Truong, Samson


    Small modeling errors in the finite element model will eventually induce errors in the structural flexibility and mass, thus propagating into unpredictable errors in the unsteady aerodynamics and the control law design. One of the primary objectives of the Multi Utility Technology Test-bed, X-56A aircraft, is the flight demonstration of active flutter suppression, and therefore in this study, the identification of the primary and secondary modes for the structural model tuning based on the flutter analysis of the X-56A aircraft. The ground vibration test-validated structural dynamic finite element model of the X-56A aircraft is created in this study. The structural dynamic finite element model of the X-56A aircraft is improved using a model tuning tool. In this study, two different weight configurations of the X-56A aircraft have been improved in a single optimization run. Frequency and the cross-orthogonality (mode shape) matrix were the primary focus for improvement, while other properties such as center of gravity location, total weight, and offdiagonal terms of the mass orthogonality matrix were used as constraints. The end result was a more improved and desirable structural dynamic finite element model configuration for the X-56A aircraft. Improved frequencies and mode shapes in this study increased average flutter speeds of the X-56A aircraft by 7.6% compared to the baseline model.

  16. Spectroscopic studies of anthracyclines: Structural characterization and in vitro tracking. (United States)

    Szafraniec, Ewelina; Majzner, Katarzyna; Farhane, Zeineb; Byrne, Hugh J; Lukawska, Malgorzata; Oszczapowicz, Irena; Chlopicki, Stefan; Baranska, Malgorzata


    A broad spectroscopic characterization, using ultraviolet-visible (UV-vis) and Fourier transform infrared absorption as well as Raman scattering, of two commonly used anthracyclines antibiotics (DOX) daunorubicin (DNR), their epimers (EDOX, EDNR) and ten selected analogs is presented. The paper serves as a comprehensive spectral library of UV-vis, IR and Raman spectra of anthracyclines in the solid state and in solution. The particular advantage of Raman spectroscopy for the measurement and analysis of individual antibiotics is demonstrated. Raman spectroscopy can be used to monitor the in vitro uptake and distribution of the drug in cells, using both 488nm and 785nm as source wavelengths, with submicrometer spatial resolution, although the cellular accumulation of the drug is different in each case. The high information content of Raman spectra allows studies of the drug-cell interactions, and so the method seems very suitable for monitoring drug uptake and mechanisms of interaction with cellular compartments at the subcellular level. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Relationship between Molecular Structure Characteristics of Feed Proteins and Protein In vitro Digestibility and Solubility. (United States)

    Bai, Mingmei; Qin, Guixin; Sun, Zewei; Long, Guohui


    The nutritional value of feed proteins and their utilization by livestock are related not only to the chemical composition but also to the structure of feed proteins, but few studies thus far have investigated the relationship between the structure of feed proteins and their solubility as well as digestibility in monogastric animals. To address this question we analyzed soybean meal, fish meal, corn distiller's dried grains with solubles, corn gluten meal, and feather meal by Fourier transform infrared (FTIR) spectroscopy to determine the protein molecular spectral band characteristics for amides I and II as well as α-helices and β-sheets and their ratios. Protein solubility and in vitro digestibility were measured with the Kjeldahl method using 0.2% KOH solution and the pepsin-pancreatin two-step enzymatic method, respectively. We found that all measured spectral band intensities (height and area) of feed proteins were correlated with their the in vitro digestibility and solubility (p≤0.003); moreover, the relatively quantitative amounts of α-helices, random coils, and α-helix to β-sheet ratio in protein secondary structures were positively correlated with protein in vitro digestibility and solubility (p≤0.004). On the other hand, the percentage of β-sheet structures was negatively correlated with protein in vitro digestibility (pproteins are closely related to their in vitro digestibility at 28 h and solubility. Furthermore, the α-helix-to-β-sheet ratio can be used to predict the nutritional value of feed proteins.

  18. Three Dimensional Viscous Finite Element Formulation For Acoustic Fluid Structure Interaction (United States)

    Cheng, Lei; White, Robert D.; Grosh, Karl


    A three dimensional viscous finite element model is presented in this paper for the analysis of the acoustic fluid structure interaction systems including, but not limited to, the cochlear-based transducers. The model consists of a three dimensional viscous acoustic fluid medium interacting with a two dimensional flat structure domain. The fluid field is governed by the linearized Navier-Stokes equation with the fluid displacements and the pressure chosen as independent variables. The mixed displacement/pressure based formulation is used in the fluid field in order to alleviate the locking in the nearly incompressible fluid. The structure is modeled as a Mindlin plate with or without residual stress. The Hinton-Huang’s 9-noded Lagrangian plate element is chosen in order to be compatible with 27/4 u/p fluid elements. The results from the full 3d FEM model are in good agreement with experimental results and other FEM results including Beltman’s thin film viscoacoustic element [2] and two and half dimensional inviscid elements [21]. Although it is computationally expensive, it provides a benchmark solution for other numerical models or approximations to compare to besides experiments and it is capable of modeling any irregular geometries and material properties while other numerical models may not be applicable. PMID:20174602


    Directory of Open Access Journals (Sweden)

    Józef SZALA


    Full Text Available Calculation results are the base for evaluation of fatigue life of structural elements during machine design processes. It results from the fact that there are no material objects in the phase of existence of a product. Reliability of tests results is an essential element in the calculation fatigue life evaluation method and it can be evaluated by comparison of the results with experimental ones. In the paper there was performed an analysis of the chosen factors essentially influencing conformity of calculation results and experimental test ones connected with basic elements of a calculation algorithm including: - elaboration and analysis of service loadings of a structural element, - determination and analysis of cyclic properties of structural elements, - selection of fatigue damage accumulation hypothesis being a description of fatigue life processes. The mentioned analysis was illustrated with examples of fatigue life tests performed in the Machine Design Department of the University of Technology and Agriculture within the research grant no. 2221/B/T02/2010/39 financed by The Ministry of Science and Higher Education and National Science Centre.

  20. Structural Anomaly Detection Using Fiber Optic Sensors and Inverse Finite Element Method (United States)

    Quach, Cuong C.; Vazquez, Sixto L.; Tessler, Alex; Moore, Jason P.; Cooper, Eric G.; Spangler, Jan. L.


    NASA Langley Research Center is investigating a variety of techniques for mitigating aircraft accidents due to structural component failure. One technique under consideration combines distributed fiber optic strain sensing with an inverse finite element method for detecting and characterizing structural anomalies anomalies that may provide early indication of airframe structure degradation. The technique identifies structural anomalies that result in observable changes in localized strain but do not impact the overall surface shape. Surface shape information is provided by an Inverse Finite Element Method that computes full-field displacements and internal loads using strain data from in-situ fiberoptic sensors. This paper describes a prototype of such a system and reports results from a series of laboratory tests conducted on a test coupon subjected to increasing levels of damage.

  1. Pounding Effects on the Earthquake Response of Adjacent Reinforced Concrete Structures Strengthened by Cable Elements (United States)

    Liolios, Angelos; Liolios, Asterios; Hatzigeorgiou, George; Radev, Stefan


    A numerical approach for estimating the effects of pounding (seismic interaction) on the response of adjacent Civil Engineering structures is presented. Emphasis is given to reinforced concrete (RC) frames of existing buildings which are seismically strengthened by cable-elements. A double discretization, in space by the Finite Element Method and in time by a direct incremental approach is used. The unilateral behaviours of both, the cable-elements and the interfaces contact-constraints, are taken strictly into account and result to inequality constitutive conditions. So, in each time-step, a non-convex linear complementarity problem is solved. It is found that pounding and cable strengthening have significant effects on the earthquake response and, hence, on the seismic upgrading of existing adjacent RC structures.

  2. High accuracy electromagnetic field solvers for cylindrical waveguides and axisymmetric structures using the finite element method

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Eric Michael [Stanford Univ., CA (United States)


    Some two-dimensional finite element electromagnetic field solvers are described and tested. For TE and TM modes in homogeneous cylindrical waveguides and monopole modes in homogeneous axisymmetric structures, the solvers find approximate solutions to a weak formulation of the wave equation. Second-order isoparametric lagrangian triangular elements represent the field. For multipole modes in axisymmetric structures, the solver finds approximate solutions to a weak form of the curl-curl formulation of Maxwell`s equations. Second-order triangular edge elements represent the radial (ρ) and axial (z) components of the field, while a second-order lagrangian basis represents the azimuthal (Φ) component of the field weighted by the radius ρ. A reduced set of basis functions is employed for elements touching the axis. With this basis the spurious modes of the curl-curl formulation have zero frequency, so spurious modes are easily distinguished from non-static physical modes. Tests on an annular ring, a pillbox and a sphere indicate the solutions converge rapidly as the mesh is refined. Computed eigenvalues with relative errors of less than a few parts per million are obtained. Boundary conditions for symmetric, periodic and symmetric-periodic structures are discussed and included in the field solver. Boundary conditions for structures with inversion symmetry are also discussed. Special corner elements are described and employed to improve the accuracy of cylindrical waveguide and monopole modes with singular fields at sharp corners. The field solver is applied to three problems: (1) cross-field amplifier slow-wave circuits, (2) a detuned disk-loaded waveguide linear accelerator structure and (3) a 90° overmoded waveguide bend. The detuned accelerator structure is a critical application of this high accuracy field solver. To maintain low long-range wakefields, tight design and manufacturing tolerances are required.

  3. Finite element analysis of a fluid-structure interaction in flexible pipe ...

    African Journals Online (AJOL)

    The obtained mathematical system is constituted of four non-linear hyperbolic partial differential equations describing the wave propagation in both pipe wall and liquid flow. The fluid-structure interaction is found to be governed by Poisson's ratio. In this steady finite element method based on Galerkin formulation is applied.

  4. Functional analysis of the complex trans-activating response element RNA structure in simian immunodeficiency virus

    NARCIS (Netherlands)

    Centlivre, Mireille; Klaver, Bep; Berkhout, Ben; Das, Atze T.


    Transcription of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) is activated through binding of the viral Tat protein to the trans-activating response (TAR) element at the 5 ' end of the nascent transcript. Whereas HIV type 1 (HIV-1) TAR folds a simple hairpin structure,

  5. Topological Design for Acoustic-Structure Interaction Problems with a Mixed Finite Element Method

    DEFF Research Database (Denmark)

    Yoon, Gil Ho; Jensen, Jakob Søndergaard; Sigmund, Ole


    to subdomain interfaces evolving during the optimization process. In this paper, we propose to use a mixed finite element formulation with displacements and pressure as primary variables (u/p formulation) which eliminates the need for explicit boundary representation. In order to describe the Helmholtz...... acoustic-structure interaction problems are optimized to show the validity of the proposed method....

  6. Structural analysis of the SNAP-8 developmental reactor fuel element cladding

    Energy Technology Data Exchange (ETDEWEB)

    Dalcher, A.W.


    Primary, secondary, and thermal stresses were calculated and evaluated for the SNAP-8 developmental reactor fuel element cladding. The effects of fabrication and assembly stresses, as well as test and operational stresses were included in the analysis. With the assumption that fuel-swelling-induced stresses are nil, the analytical results indicate that the cladding assembly is structurally adequate for the proposed operation.

  7. Asynchronous Communication: Investigating the Influences of Relational Elements and Background on the Framing Structure of Emails (United States)

    AlAfnan, Mohammad Awad


    This study explored the influences of relational elements and the background of communicators on the framing structure of email messages that were exchanged in an educational Institute in Malaysia. The investigation revealed that social distance played a more significant role than power relations as Malaysian respondents are, generally, more…

  8. DYCAST: A finite element program for the crash analysis of structures (United States)

    Pifko, A. B.; Winter, R.; Ogilvie, P.


    DYCAST is a nonlinear structural dynamic finite element computer code developed for crash simulation. The element library contains stringers, beams, membrane skin triangles, plate bending triangles and spring elements. Changing stiffnesses in the structure are accounted for by plasticity and very large deflections. Material nonlinearities are accommodated by one of three options: elastic-perfectly plastic, elastic-linear hardening plastic, or elastic-nonlinear hardening plastic of the Ramberg-Osgood type. Geometric nonlinearities are handled in an updated Lagrangian formulation by reforming the structure into its deformed shape after small time increments while accumulating deformations, strains, and forces. The nonlinearities due to combined loadings are maintained, and stiffness variation due to structural failures are computed. Numerical time integrators available are fixed-step central difference, modified Adams, Newmark-beta, and Wilson-theta. The last three have a variable time step capability, which is controlled internally by a solution convergence error measure. Other features include: multiple time-load history tables to subject the structure to time dependent loading; gravity loading; initial pitch, roll, yaw, and translation of the structural model with respect to the global system; a bandwidth optimizer as a pre-processor; and deformed plots and graphics as post-processors.

  9. Electronic Origin of the Orthorhombic Cmca Structure in Compressed Elements and Binary Alloys

    Directory of Open Access Journals (Sweden)

    Valentina F. Degtyareva


    Full Text Available Formation of the complex structure with 16 atoms in the orthorhombic cell, space group Cmca (Pearson symbol oC16, was experimentally found under high pressure in the alkali elements (K, Rb, Cs and polyvalent elements of groups IV (Si, Ge and V (Bi. Intermetallic phases with this structure form under pressure in binary Bi-based alloys (Bi-Sn, Bi-In, Bi-Pb. Stability of the Cmca-oC16 structure is analyzed within the nearly free-electron model in the frame of Fermi sphere-Brillouin zone interaction. A Brillouin-Jones zone formed by a group of strong diffraction reflections close to the Fermi sphere is the reason for the reduction of crystal energy and stabilization of the structure. This zone corresponds well to the four valence electrons in Si and Ge, and leads to assume an spd-hybridization for Bi. To explain the stabilization of this structure within the same model in alkali metals, that are monovalents at ambient conditions, a possibility of an overlap of the core, and valence band electrons at strong compression, is considered. The assumption of the increase in the number of valence electrons helps to understand sequences of complex structures in compressed alkali elements and unusual changes in their physical properties, such as electrical resistance and superconductivity.


    DEFF Research Database (Denmark)

    Sørensen, Nanna Skall; Skovgaard, Kerstin; Vorsholt, Henriette

    antigen-presentation. Different PAMPs will activate different signalling pathways, resulting in specific cytokine signatures, which will influence the orientation of a developing immune response. In the pig, the range of antibodies available for cytokine-detection is limited, and so cytokines are often......Pathogen-associated molecular patterns (PAMPs) are conserved microbial structures recognized by pattern-recognition receptors (PRRs) of the innate immune system. Binding of PAMPs by certain PRRs on dendritic cells induces these to express costimulatory molecules and cytokines, enabling an inductive...

  11. Algorithms and data structures for massively parallel generic adaptive finite element codes

    KAUST Repository

    Bangerth, Wolfgang


    Today\\'s largest supercomputers have 100,000s of processor cores and offer the potential to solve partial differential equations discretized by billions of unknowns. However, the complexity of scaling to such large machines and problem sizes has so far prevented the emergence of generic software libraries that support such computations, although these would lower the threshold of entry and enable many more applications to benefit from large-scale computing. We are concerned with providing this functionality for mesh-adaptive finite element computations. We assume the existence of an "oracle" that implements the generation and modification of an adaptive mesh distributed across many processors, and that responds to queries about its structure. Based on querying the oracle, we develop scalable algorithms and data structures for generic finite element methods. Specifically, we consider the parallel distribution of mesh data, global enumeration of degrees of freedom, constraints, and postprocessing. Our algorithms remove the bottlenecks that typically limit large-scale adaptive finite element analyses. We demonstrate scalability of complete finite element workflows on up to 16,384 processors. An implementation of the proposed algorithms, based on the open source software p4est as mesh oracle, is provided under an open source license through the widely used deal.II finite element software library. © 2011 ACM 0098-3500/2011/12-ART10 $10.00.

  12. Handbook of the band structure of elemental solids from Z = 1 to Z = 112

    CERN Document Server

    Papaconstantopoulos, Dimitris A


    This handbook presents electronic structure data and tabulations of Slater-Koster parameters for the whole periodic table. This second edition presents data sets for all elements up to Z = 112, Copernicium, whereas the first edition contained only 53 elements. In this new edition, results are given for the equation of state of the elements together with the parameters of a Birch fit, so that the reader can regenerate the results and derive additional information, such as Pressure-Volume relations and variation of Bulk Modulus with Pressure. For each element, in addition to the equation of state, the energy bands, densities of states, and a set of tight-binding parameters is provided. For a majority of elements, the tight-binding parameters are presented for both a two- and three-center approximation. For the hcp structure, new three-center tight-binding results are given. Other new material in this edition include: energy bands and densities of states of all rare-earth metals, a discussion of the McMillan-Gas...

  13. Finite Elements Based on Strong and Weak Formulations for Structural Mechanics: Stability, Accuracy and Reliability

    Directory of Open Access Journals (Sweden)

    Francesco Tornabene


    Full Text Available The authors are presenting a novel formulation based on the Differential Quadrature (DQ method which is used to approximate derivatives and integrals. The resulting scheme has been termed strong and weak form finite elements (SFEM or WFEM, according to the numerical scheme employed in the computation. Such numerical methods are applied to solve some structural problems related to the mechanical behavior of plates and shells, made of isotropic or composite materials. The main differences between these two approaches rely on the initial formulation – which is strong or weak (variational – and the implementation of the boundary conditions, that for the former include the continuity of stresses and displacements, whereas in the latter can consider the continuity of the displacements or both. The two methodologies consider also a mapping technique to transform an element of general shape described in Cartesian coordinates into the same element in the computational space. Such technique can be implemented by employing the classic Lagrangian-shaped elements with a fixed number of nodes along the element edges or blending functions which allow an “exact mapping” of the element. In particular, the authors are employing NURBS (Not-Uniform Rational B-Splines for such nonlinear mapping in order to use the “exact” shape of CAD designs.

  14. Storage conditions of skin affect tissue structure and in vitro percutaneus penetration

    DEFF Research Database (Denmark)

    Nielsen, Jesper Bo; Bagatolli, Luis


    skin at -20oC causes structural changes in the upper Stratum Corneum observable with image techniques such as multiphoton excitation fluorescence microscopy. The presently available literature does, however, not support that the observed structural damage to the integrity is sufficient to cause......For logistic and practical reasons it is difficult to perform in vitro studies on percutaneous penetration on fresh human skin obtained directly from surgery. Skin samples are therefore often kept frozen until use. The present chapter present the available literature on the topic. Storage of human...... a general and significantly increased in vitro percutaneous penetration across human skin stored at -20oC. Use of skin stored at -20oC for in vitro studies on percutaneous penetration therefore seems acceptable as long as the barrier integrity is documented. Storage of human skin at -80oC causes significant...

  15. A Signal Based Triangular Structuring Element for Mathematical Morphological Analysis and Its Application in Rolling Element Bearing Fault Diagnosis

    Directory of Open Access Journals (Sweden)

    Zhaowen Chen


    Full Text Available Mathematical morphology (MM is an efficient nonlinear signal processing tool. It can be adopted to extract fault information from bearing signal according to a structuring element (SE. Since the bearing signal features differ for every unique cause of failure, the SEs should be well tailored to extract the fault feature from a particular signal. In the following, a signal based triangular SE according to the statistics of the magnitude of a vibration signal is proposed, together with associated methodology, which processes the bearing signal by MM analysis based on proposed SE to get the morphology spectrum of a signal. A correlation analysis on morphology spectrum is then employed to obtain the final classification of bearing faults. The classification performance of the proposed method is evaluated by a set of bearing vibration signals with inner race, ball, and outer race faults, respectively. Results show that all faults can be detected clearly and correctly. Compared with a commonly used flat SE, the correlation analysis on morphology spectrum with proposed SE gives better performance at fault diagnosis of bearing, especially the identification of the location of outer race fault and the level of fault severity.

  16. Industrial approach to static and dynamic finite element modeling of composite structures with embedded actuators (United States)

    Hauch, Randall M.


    A finite element modeling technique has been developed to accurately predict both the static and dynamic response of a structure containing embedded piezoelectric actuators. This process utilizes a commercially available and benchmarked finite element program and can be used with shell or solid elements in any static analysis, time-domain or frequency-domain dynamic analysis. It is possible to apply the piezoelectric loads while simultaneously applying other mechanical or thermal loads even though the induced strain of the piezoelectric actuators is modeled using thermal expansion. The technique uses superelements to apply the thermal loads at any frequency and magnitude and to incorporate a fine mesh near the actuator even if a course mesh is used over the remaining portions of the structure. The technique's generic and modular nature allows a complex actuator superelement to be used multiple times in multiple smart structure models. Experiments conducted on composite coupons with embedded actuators validate the current modeling technique and demonstrate the method's successful prediction of the dynamic response of the specimens. This process is one of several smart structure modeling techniques being developed under the Synthesis and Processing of Intelligent Cost Effective Structures program sponsored by the Advanced Research Projects Agency.

  17. Numerical investigation of soil and buried structures using finite element analysis

    Directory of Open Access Journals (Sweden)

    Meysam Shirzad Shahrivar


    Full Text Available Today the important of studying soil effect on behavior of soil  contacted structures such as foundations, piles,  retaining wall and other similar structures is so much that neglecting of soil-structure interaction effect can cause to untrue results. In this paper soil-structure interaction simulation was done by using Finite element method analysis with ABAQUS version 6.13-14.The results has been presented based on pile function in contact with soil, vertical stresses in soil and structures, pore pressure in drained and undrained condition and underground water level.Final conclusions revealed that pore pressure effect is not uniform on all parts of pile and amount of pore pressure increment in top elements is lower than down elements of  pile.Further it was proven that average amount of vertical stress on end of pile is    of this stress on top of the pile. thus it was concluded that 70% of pile bearing capacity is depend on friction of soil and pile contact surface.

  18. Text localization using standard deviation analysis of structure elements and support vector machines (United States)

    Zagoris, Konstantinos; Chatzichristofis, Savvas A.; Papamarkos, Nikos


    A text localization technique is required to successfully exploit document images such as technical articles and letters. The proposed method detects and extracts text areas from document images. Initially a connected components analysis technique detects blocks of foreground objects. Then, a descriptor that consists of a set of suitable document structure elements is extracted from the blocks. This is achieved by incorporating an algorithm called Standard Deviation Analysis of Structure Elements (SDASE) which maximizes the separability between the blocks. Another feature of the SDASE is that its length adapts according to the requirements of the application. Finally, the descriptor of each block is used as input to a trained support vector machines that classify the block as text or not. The proposed technique is also capable of adjusting to the text structure of the documents. Experimental results on benchmarking databases demonstrate the effectiveness of the proposed method.

  19. Finite element modelling of crash response of composite aerospace sub-floor structures (United States)

    McCarthy, M. A.; Harte, C. G.; Wiggenraad, J. F. M.; Michielsen, A. L. P. J.; Kohlgrüber, D.; Kamoulakos, A.

    Composite energy-absorbing structures for use in aircraft are being studied within a European Commission research programme (CRASURV - Design for Crash Survivability). One of the aims of the project is to evaluate the current capabilities of crashworthiness simulation codes for composites modelling. This paper focuses on the computational analysis using explicit finite element analysis, of a number of quasi-static and dynamic tests carried out within the programme. It describes the design of the structures, the analysis techniques used, and the results of the analyses in comparison to the experimental test results. It has been found that current multi-ply shell models are capable of modelling the main energy-absorbing processes at work in such structures. However some deficiencies exist, particularly in modelling fabric composites. Developments within the finite element code are taking place as a result of this work which will enable better representation of composite fabrics.

  20. Studying the capture cross sections of structural elements by measuring neutron balance in multiplying media

    Energy Technology Data Exchange (ETDEWEB)

    Golubev, V.N.; Dulin, V.A.; Kazanskij, Yu.A.


    To refine neutron capture cross sections for structural elements used in fast power reactors the neutron balance in multiplying media with neutron multiplication factor K/sub infinity/=1 has been studied at KBR and ERMINE critical assemblies. Reactivity of multiplying cells consisting of uranium and structural elements is measured as well as reactivity coefficients of individual structural materials. Corresponding calculations are performed using the versions of group constants applied in designing the fast reactors in the USSR and France. The CARNAVAL 4 constant version predicts well a fraction of neutron absorptions in steel and nickel for the spectra typical for a power reactor (ERMINE assembly). For softer spectra (KBR assembly) the agreement with experiment is better when the BNAB-78 constant version is used.

  1. Text localization using standard deviation analysis of structure elements and support vector machines

    Directory of Open Access Journals (Sweden)

    Zagoris Konstantinos


    Full Text Available Abstract A text localization technique is required to successfully exploit document images such as technical articles and letters. The proposed method detects and extracts text areas from document images. Initially a connected components analysis technique detects blocks of foreground objects. Then, a descriptor that consists of a set of suitable document structure elements is extracted from the blocks. This is achieved by incorporating an algorithm called Standard Deviation Analysis of Structure Elements (SDASE which maximizes the separability between the blocks. Another feature of the SDASE is that its length adapts according to the requirements of the application. Finally, the descriptor of each block is used as input to a trained support vector machines that classify the block as text or not. The proposed technique is also capable of adjusting to the text structure of the documents. Experimental results on benchmarking databases demonstrate the effectiveness of the proposed method.

  2. Influence of Finite Element Size in Residual Strength Prediction of Composite Structures (United States)

    Satyanarayana, Arunkumar; Bogert, Philip B.; Karayev, Kazbek Z.; Nordman, Paul S.; Razi, Hamid


    The sensitivity of failure load to the element size used in a progressive failure analysis (PFA) of carbon composite center notched laminates is evaluated. The sensitivity study employs a PFA methodology previously developed by the authors consisting of Hashin-Rotem intra-laminar fiber and matrix failure criteria and a complete stress degradation scheme for damage simulation. The approach is implemented with a user defined subroutine in the ABAQUS/Explicit finite element package. The effect of element size near the notch tips on residual strength predictions was assessed for a brittle failure mode with a parametric study that included three laminates of varying material system, thickness and stacking sequence. The study resulted in the selection of an element size of 0.09 in. X 0.09 in., which was later used for predicting crack paths and failure loads in sandwich panels and monolithic laminated panels. Comparison of predicted crack paths and failure loads for these panels agreed well with experimental observations. Additionally, the element size vs. normalized failure load relationship, determined in the parametric study, was used to evaluate strength-scaling factors for three different element sizes. The failure loads predicted with all three element sizes provided converged failure loads with respect to that corresponding with the 0.09 in. X 0.09 in. element size. Though preliminary in nature, the strength-scaling concept has the potential to greatly reduce the computational time required for PFA and can enable the analysis of large scale structural components where failure is dominated by fiber failure in tension.

  3. Development of a microbeam PIXE system for additive light elements in structural materials (United States)

    Yamazaki, A.; Sasa, K.; Ishii, S.; Kurosawa, M.; Tomita, S.; Shiina, Y.; Shiki, S.; Fujii, G.; Ukibe, M.; Ohkubo, M.; Uedono, A.; Kita, E.


    A new submicron scanning nuclear microprobe beam line was constructed in early 2016 at the accelerator facility of the University of Tsukuba, Japan. A microbeam scanning endstage (OM-2000, Oxford Microbeams, Oxford, UK) was installed at the end of this system. The distance from the object slit to the target position is 8730 mm and the working distance is 180 mm. This ion microbeam system will be used mainly for X-ray imaging of two-dimensional distributions of light elements in structural materials using particle-induced X-ray emission (PIXE). A silicon drift detector (SDD) with a thin window of Si3N4 was installed to detect characteristic X-rays emitted from light elements such as B, C, and N, which are common additive elements in structural materials. In addition, a superconducting tunnel junction (STJ) array detector is going to be installed to perform PIXE measurements more efficiently. By combining a microbeam scanning technology with the X-ray detectors, we plan to obtain two-dimensional maps of additive light elements in structural materials. Experiments for obtaining proton microbeams are ongoing, and a 6 MeV proton beam with a diameter of between 12 and 20 μm has been obtained to date.

  4. A multi-mesh finite element method for phase-field based photonic band structure optimization (United States)

    Wu, Shengyang; Hu, Xianliang; Zhu, Shengfeng


    A novel finite element method with multiple meshes is proposed, which is applied to solve the phase-field models for photonic band structures optimization. In our approach, fine meshes are used for the phase field evolution, which allows fine resolution for shape representations. The coarse meshes are adopted for the finite element analysis of the state equation. Such a multi-mesh approach could save a considerable amount of computational costs. Numerical convergence is illustrated through comparisons between our computational results and benchmarks. The efficiency and robustness of the multi-mesh approach are also shown.

  5. Effect of alkaline elements on the reactivity, strength and structural properties of blast furnace cokes

    Directory of Open Access Journals (Sweden)

    A. Bhattacharyya


    Full Text Available The present study concerns itself on the adverse effects of alkaline elements like sodium and potassium on blast furnace cokes. To achieve a deeper insight on the effects of alkaline elements on coke reactivity and strength, industrial coke samples impregnated with different alkaline species in various amounts have been tested under standard conditions to find out their Coke Reactivity Index (CRI and Coke Strength after Reaction (CSR values. Scanning electron microscopy, petrographic and Raman Spectrometric investigations demonstrate the change of structural properties. The mechanism of catalysis has been postulated.

  6. Structural features of condensed tannins affect in vitro ruminal methane production and fermentation characteristics

    NARCIS (Netherlands)



    An in vitro study was conducted to investigate the effects of condensed tannin (CT) structural properties, i.e. average polymer size (or mean degree of polymerization), percentage of cis flavan-3-ols and percentage of prodelphinidins in CT extracts on methane (CH 4 ) production and fermentation

  7. Diversity of condensed tannin structures affects rumen in vitro methane production in sainfoin (Onobrychis viciifolia) accessions

    NARCIS (Netherlands)

    Hatew, B.; Hayot Carbonero, C.; Stringano, E.; Sales, L.F.; Smith, L.M.J.; Mueller-Harvey, I.; Hendriks, W.H.; Pellikaan, W.F.


    Sainfoin is a non-bloating temperate forage legume with a moderate-to-high condensed tannin (CT) content. This study investigated whether the diversity of sainfoin accessions in terms of CT structures and contents could be related to rumen in vitro gas and methane (CH4) production and fermentation

  8. Structural features of condensed tannins affect in vitro ruminal methane production and fermentation characteristics

    NARCIS (Netherlands)

    Huyen, N.T.; Fryganas, C.; Uittenbogaard, G.; Mueller-Harvey, I.; Verstegen, M.W.A.; Hendriks, W.H.; Pellikaan, W.F.


    An in vitro study was conducted to investigate the effects of condensed tannin (CT) structural properties, i.e. average polymer size (or mean degree of polymerization), percentage of cis flavan-3-ols and percentage of prodelphinidins in CT extracts on methane (CH4) production and

  9. Synthesis, structure analysis, anti-bacterial and in vitro anti-cancer ...

    Indian Academy of Sciences (India)

    DOI 10.1007/s12039-015-0824-z. Synthesis, structure analysis, anti-bacterial and in vitro anti-cancer activity of new Schiff base and its copper complex derived from sulfamethoxazole. I RAMA∗ and R SELVAMEENA. PG and Research Department of Chemistry, Seethalakshmi Ramaswami College,. Tiruchirappalli 620 002 ...

  10. Structure-activity studies: in vitro antileishmanial and antimalarial activities of anthraquinones from Morinda lucida. (United States)

    Sittie, A A; Lemmich, E; Olsen, C E; Hviid, L; Kharazmi, A; Nkrumah, F K; Christensen, S B


    Anthraquinones have been isolated by bioassay-guided fractionation from Morinda lucida. Structure-activity studies show that an aldehyde group at C-2 and a phenolic hydroxy group at C-3 enhance the activity of the anthraquinones against the growth of Plasmodium falciparum and promastigotes of Leishmania major in vitro.

  11. Anatomical structure of african violet (Saintpaulia ionantha L. vitro- and exvitroplantlets

    Directory of Open Access Journals (Sweden)



    Full Text Available In this article we study the histo-anatomical structure of vegetative organs of African violet (Saintpaulia ionantha L. vitro- and exvitroplantlets in comparison with similar aspects at the same organs of the greenhouse plants (control lot. The phytoinoculs vitroculture period was 120 days, the ex vitro acclimatization for the exvitroplantlets needed 30 days, and the greenhouse cultivar was 2 years old. Finally, we found that only rootlets of the vitroplantlets had a primary structure because at stemlets level has been identified the cambium presence still the vitroculture period. The cortical parenchyma cells at vitro- and exvitroplantlets was larger and less compact in comparison with those of control lot. Also, in the vitroplantlet rootles and stemlets the report cortex:central cylinder was much higher and vascular bundle was very poorly represented that at exvitroplantlets, but especially in comparison with these aspects in the plants grown in natural conditions. The spongy parenchyma at leaflets from in vitro culture was composed of fewer cell layers which was larger and less compact in comparison with those of exvitroplantlet leaf homologous layers and with the same layers from the leaf of greenhouse plants. At in vitro leaflets the peryphloemic protective mechanical tissue was at an early forming stage. However, we consider these differences as being due to the plants normal ontogenetic development.

  12. Energy Finite Element Analysis Developments for Vibration Analysis of Composite Aircraft Structures (United States)

    Vlahopoulos, Nickolas; Schiller, Noah H.


    The Energy Finite Element Analysis (EFEA) has been utilized successfully for modeling complex structural-acoustic systems with isotropic structural material properties. In this paper, a formulation for modeling structures made out of composite materials is presented. An approach based on spectral finite element analysis is utilized first for developing the equivalent material properties for the composite material. These equivalent properties are employed in the EFEA governing differential equations for representing the composite materials and deriving the element level matrices. The power transmission characteristics at connections between members made out of non-isotropic composite material are considered for deriving suitable power transmission coefficients at junctions of interconnected members. These coefficients are utilized for computing the joint matrix that is needed to assemble the global system of EFEA equations. The global system of EFEA equations is solved numerically and the vibration levels within the entire system can be computed. The new EFEA formulation for modeling composite laminate structures is validated through comparison to test data collected from a representative composite aircraft fuselage that is made out of a composite outer shell and composite frames and stiffeners. NASA Langley constructed the composite cylinder and conducted the test measurements utilized in this work.

  13. Development of Finite Elements for Two-Dimensional Structural Analysis Using the Integrated Force Method (United States)

    Kaljevic, Igor; Patnaik, Surya N.; Hopkins, Dale A.


    The Integrated Force Method has been developed in recent years for the analysis of structural mechanics problems. This method treats all independent internal forces as unknown variables that can be calculated by simultaneously imposing equations of equilibrium and compatibility conditions. In this paper a finite element library for analyzing two-dimensional problems by the Integrated Force Method is presented. Triangular- and quadrilateral-shaped elements capable of modeling arbitrary domain configurations are presented. The element equilibrium and flexibility matrices are derived by discretizing the expressions for potential and complementary energies, respectively. The displacement and stress fields within the finite elements are independently approximated. The displacement field is interpolated as it is in the standard displacement method, and the stress field is approximated by using complete polynomials of the correct order. A procedure that uses the definitions of stress components in terms of an Airy stress function is developed to derive the stress interpolation polynomials. Such derived stress fields identically satisfy the equations of equilibrium. Moreover, the resulting element matrices are insensitive to the orientation of local coordinate systems. A method is devised to calculate the number of rigid body modes, and the present elements are shown to be free of spurious zero-energy modes. A number of example problems are solved by using the present library, and the results are compared with corresponding analytical solutions and with results from the standard displacement finite element method. The Integrated Force Method not only gives results that agree well with analytical and displacement method results but also outperforms the displacement method in stress calculations.

  14. Spectral finite element method wave propagation, diagnostics and control in anisotropic and inhomogeneous structures

    CERN Document Server

    Gopalakrishnan, Srinivasan; Roy Mahapatra, Debiprosad


    The use of composites and Functionally Graded Materials (FGMs) in structural applications has increased. FGMs allow the user to design materials for a specified functionality and have many uses in structural engineering. However, the behaviour of these structures under high-impact loading is not well understood. This book is the first to apply the Spectral Finite Element Method (SFEM) to inhomogeneous and anisotropic structures in a unified and systematic manner. It focuses on some of the problems with this media which were previously thought unmanageable. Types of SFEM for regular and damaged 1-D and 2-D waveguides, solution techniques, methods of detecting the presence of damages and their locations, and methods for controlling the wave propagation responses are discussed. Tables, figures and graphs support the theory and case studies are included. This book is of value to senior undergraduates and postgraduates studying in this field, and researchers and practicing engineers in structural integrity.

  15. Elements for measuring the complexity of 3D structural models: Connectivity and geometry (United States)

    Pellerin, Jeanne; Caumon, Guillaume; Julio, Charline; Mejia-Herrera, Pablo; Botella, Arnaud


    The reliable modeling of three-dimensional complex geological structures can have a major impact on forecasting and managing natural resources and on predicting seismic and geomechanical hazards. However, the qualification of a model as structurally complex is often qualitative and subjective making the comparison of the capabilities and performances of various geomodeling methods or software difficult. In this paper, we consider the notion of structural complexity from a geometrical point of view and argue that it can be characterized using general metrics computed on three-dimensional sealed structural models. We propose global and local measures of the connectivity and of the geometry of the model components and show how they permit to classify nine 3D synthetic structural models. Depending on the complexity elements favored, the classification varies. The models we introduce could be used as benchmark models for geomodeling algorithms.

  16. Elements of solid state electronics based on soi-structures and si whiskers for cryogenic temperatures

    Directory of Open Access Journals (Sweden)

    Druzhinin A. A.


    Full Text Available The paper presents the study results of electrical properties of polycrystalline silicon films in silicon-on-insulator structures and Si whiskers in the temperature range of 4,2—70 K obtained by impedance measurements in the frequency range from 10 Hz to 250 kHz and the possibility of their use in solid-state electronics, functioning at cryogenic temperatures. Characteristics of samples obtained with impedance measurements allow to predict certain specifications of reactive elements of solid state electronics based on polycrystalline and single crystalline silicon, operable at low temperatures. Using the established dependencies, separate elements in the form of solid-state electronics capacitive and inductive elements as well as a combined system in an oscillatory circuit, operable at cryogenic temperatures, have been suggested. The features of developed system depend on the structure of samples and their doping level, which allows to change the required parameters of the elements of solid state electronics in a wide range.

  17. Experimental verifications of a structural damage identification technique using reduced order finite-element model (United States)

    Li, Rui; Zhou, Li; Yang, Jann N.


    An objective of the structural health monitoring system is to identify the state of the structure and to detect the damage when it occurs. Analysis techniques for the damage identification of structures, based on vibration data measured from sensors, have received considerable attention. Recently, a new damage tracking technique, referred to as the adaptive quadratic sum-square error (AQSSE) technique, has been proposed, and simulation studies demonstrated that the AQSSE technique is quite effective in identifying structural damages. In this paper, the adaptive quadratic sumsquare error (AQSSE) along with the reduced-order finite-element method is proposed to identify the damages of complex structures. Experimental tests were conducted to verify the capability of the proposed damage detection approach. A series of experimental tests were performed using a scaled cantilever beam subject to the white noise and sinusoidal excitations. The capability of the proposed reduced-order finite-element based adaptive quadratic sum-square error (AQSSE) method in detecting the structural damage is demonstrated by the experimental results.

  18. Coupled Finite Volume and Finite Element Method Analysis of a Complex Large-Span Roof Structure (United States)

    Szafran, J.; Juszczyk, K.; Kamiński, M.


    The main goal of this paper is to present coupled Computational Fluid Dynamics and structural analysis for the precise determination of wind impact on internal forces and deformations of structural elements of a longspan roof structure. The Finite Volume Method (FVM) serves for a solution of the fluid flow problem to model the air flow around the structure, whose results are applied in turn as the boundary tractions in the Finite Element Method problem structural solution for the linear elastostatics with small deformations. The first part is carried out with the use of ANSYS 15.0 computer system, whereas the FEM system Robot supports stress analysis in particular roof members. A comparison of the wind pressure distribution throughout the roof surface shows some differences with respect to that available in the engineering designing codes like Eurocode, which deserves separate further numerical studies. Coupling of these two separate numerical techniques appears to be promising in view of future computational models of stochastic nature in large scale structural systems due to the stochastic perturbation method.

  19. Coupled Finite Volume and Finite Element Method Analysis of a Complex Large-Span Roof Structure

    Directory of Open Access Journals (Sweden)

    Szafran J.


    Full Text Available The main goal of this paper is to present coupled Computational Fluid Dynamics and structural analysis for the precise determination of wind impact on internal forces and deformations of structural elements of a longspan roof structure. The Finite Volume Method (FVM serves for a solution of the fluid flow problem to model the air flow around the structure, whose results are applied in turn as the boundary tractions in the Finite Element Method problem structural solution for the linear elastostatics with small deformations. The first part is carried out with the use of ANSYS 15.0 computer system, whereas the FEM system Robot supports stress analysis in particular roof members. A comparison of the wind pressure distribution throughout the roof surface shows some differences with respect to that available in the engineering designing codes like Eurocode, which deserves separate further numerical studies. Coupling of these two separate numerical techniques appears to be promising in view of future computational models of stochastic nature in large scale structural systems due to the stochastic perturbation method.

  20. Modified Immersed Finite Element Method For Fully-Coupled Fluid-Structure Interations (United States)

    Wang, Xingshi; Zhang, Lucy T.


    In this paper, we develop a “modified” immersed finite element method (mIFEM), a non-boundary-fitted numerical technique, to study fluid-structure interactions. Using this method, we can more precisely capture the solid dynamics by solving the solid governing equation instead of imposing it based on the fluid velocity field as in the original immersed finite element (IFEM). Using the IFEM may lead to severe solid mesh distortion because the solid deformation is been over-estimated, especially for high Reynolds number flows. In the mIFEM, the solid dynamics is solved using appropriate boundary conditions generated from the surrounding fluid, therefore produces more accurate and realistic coupled solutions. We show several 2-D and 3-D testing cases where the mIFEM has a noticeable advantage in handling complicated fluid-structure interactions when the solid behavior dominates the fluid flow. PMID:24223445

  1. Towards isotope shift and hyperfine structure measurements of the element nobelium

    Energy Technology Data Exchange (ETDEWEB)

    Chhetri, Premaditya; Lautenschlaeger, Felix; Walther, Thomas [Institut fuer Angewandte Physik, TU Darmstadt, D-64289 Darmstadt (Germany); Laatiaoui, Mustapha [Helmholtz Institut Mainz, D-55099 Mainz (Germany); Block, Michael; Hessberger, Fritz-Peter [Helmholtz Institut Mainz, D-55099 Mainz (Germany); GSI, D-64291 Darmstadt (Germany); Lauth, Werner; Backe, Hartmut [Institut fuer Kernphysik, JGU Mainz, D-55122 Mainz (Germany); Kunz, Peter [TRIUMF, D-V6T2A3 Vancouver (Canada)


    Laser spectroscopy on the heaviest elements is of great interest as it allows the study of the evolution of relativistic effects on their atomic structure. In our experiment we exploit the Radiation Detected Resonance Ionization Spectroscopy technique and use excimer-laser pumped dye lasers to search for the first time the {sup 1}P{sub 1} level in {sup 254}No. Etalons will be used in the forthcoming experiments at GSI, Darmstadt, to narrow down the bandwidth of the dye lasers to 0.04 cm{sup -1}, for the determination of the isotope shift and hyperfine splitting of {sup 253,} {sup 255}No. In this talk results from preparatory hyperfine structure studies in nat. ytterbium and the perspectives for future experiments of the heaviest elements are discussed.

  2. Structural Orders of Wheat Starch Do Not Determine the In Vitro Enzymatic Digestibility. (United States)

    Wang, Shujun; Wang, Shaokang; Liu, Lu; Wang, Shuo; Copeland, Les


    In this study, we elucidated the underlying mechanisms that are responsible for the rate-limiting step for wheat starch digestion. Wheat starch samples with a degree of gelatinization (DG) ranging from 0 to 100% were prepared. As DG increased, the ordered structures of the starch were disrupted increasingly. In contrast, almost all of the increase in the rate and extent of in vitro enzymatic digestion coincided with a DG of only 6% and a minor loss of structural order. As DG increased beyond 6%, digestibility of the starch increased only slightly. We propose that the access and binding of enzymes to starch is greatly increased with only a small DG, which is followed by the simultaneous hydrolysis of crystalline and amorphous areas in gelatinized starch. In vitro enzymatic digestibility of starch was determined predominantly by enzyme binding to starch rather than the ordered structures of starch.

  3. Testing the Big Bang: Light elements, neutrinos, dark matter and large-scale structure (United States)

    Schramm, David N.


    Several experimental and observational tests of the standard cosmological model are examined. In particular, a detailed discussion is presented regarding: (1) nucleosynthesis, the light element abundances, and neutrino counting; (2) the dark matter problems; and (3) the formation of galaxies and large-scale structure. Comments are made on the possible implications of the recent solar neutrino experimental results for cosmology. An appendix briefly discusses the 17 keV thing and the cosmological and astrophysical constraints on it.

  4. Local deformation method for measuring element tension in space deployable structures

    Directory of Open Access Journals (Sweden)

    Belov Sergey


    Full Text Available The article describes the local deformation method to determine the tension of cord and thin membrane elements in space deployable structure as antenna reflector. Possible measuring instrument model, analytical and numerical solutions and experimental results are presented. The boundary effects on measurement results of metallic mesh reflector surface tension are estimated. The study case depicting non-uniform reflector surface tension is considered.

  5. Political “genotype” as a structural element of political culture

    Directory of Open Access Journals (Sweden)

    N. V. Karpova


    Full Text Available The article is devoted to the issue of genetic foundations of political culture in the context of the socio-political system changes. The author elaborates the concept of “political genotype” as a sustainable structural element of political culture that determines its content and the possibility of permissible variation. In this paper the main forms of existence of political genotype and its functions are also investigated; and “genetic” mechanism of political culture succession is explored.

  6. Structured Analysis: Review of ILS Element E13 Reliability, Availability and Maintainability (United States)



  7. Large finger joints of glulam load-bearing elements in timber structures


    Krištof, Igor


    In the graduation thesis are presented large finger joints. Large finger joints are glued timber joints, used for connecting wooden elements, usually glulam beams. Frequently this kind of joints connect corners of three – hinged frames, used for building prefabricated timber structures with spans up to 40 m. In comparison with mechanical joints, glued joints are cheaper and they have excellent load – carrying capacity, but poor ductility. I have installed large finger joints in the glulam fra...

  8. Multiscale Nonconforming Finite Element Computation to Small Periodic Composite Materials of Elastic Structures on Anisotropic Meshes

    Directory of Open Access Journals (Sweden)

    Ying Hao


    Full Text Available The small periodic elastic structures of composite materials with the multiscale asymptotic expansion and homogenized method are discussed. A nonconforming Crouzeix-Raviart finite element is applied to calculate every term of the asymptotic expansion on anisotropic meshes. The approximation scheme to the higher derivatives of the homogenized solution is also derived. Finally, the optimal error estimate in ·h for displacement vector is obtained.

  9. Cross-sectional mapping for refined beam elements with applications to shell-like structures (United States)

    Pagani, A.; de Miguel, A. G.; Carrera, E.


    This paper discusses the use of higher-order mapping functions for enhancing the physical representation of refined beam theories. Based on the Carrera unified formulation (CUF), advanced one-dimensional models are formulated by expressing the displacement field as a generic expansion of the generalized unknowns. According to CUF, a novel physically/geometrically consistent model is devised by employing Legendre-like polynomial sets to approximate the generalized unknowns at the cross-sectional level, whereas a local mapping technique based on the blending functions method is used to describe the exact physical boundaries of the cross-section domain. Classical and innovative finite element methods, including hierarchical p-elements and locking-free integration schemes, are utilized to solve the governing equations of the unified beam theory. Several numerical applications accounting for small displacements/rotations and strains are discussed, including beam structures with cross-sectional curved edges, cylindrical shells, and thin-walled aeronautical wing structures with reinforcements. The results from the proposed methodology are widely assessed by comparisons with solutions from the literature and commercial finite element software tools. The attention is focussed on the high computational efficiency and the marked capabilities of the present beam model, which can deal with a broad spectrum of structural problems with unveiled accuracy in terms of geometrical representation of the domain boundaries.

  10. Measurement of Join Patch Properties and Their Integration into Finite-Element Calculations of Assembled Structures

    Directory of Open Access Journals (Sweden)

    A. Schmidt


    Full Text Available The vibration and damping characteristics of an assembled structure made of steel are investigated by an experimental modal analysis and compared with the results of a finite element modal analysis. A generic experiment is carried out to evaluate the stiffness and the damping properties of the structure's join patches. Using these results, an appropriate finite element model of the structure is developed where the join patches are represented by thin-layer elements containing material properties which are derived from the generic experiment's results. The joint's stiffness is modeled by orthotropic material behavior whereas the damping properties are represented by the model of constant hysteresis, leading to a complex-valued stiffness matrix. A comparison between the experimental and the numerical modal analysis shows good agreement. A more detailed damping model in conjunction with an optimization procedure for the joint's parameters results in an improved correlation between the experimental and the numerical modal quantities and reveals that the results of the generic experiment are sound.

  11. Structural Stability and Dynamics of FGM Plates Using an Improved 8-ANS Finite Element

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    Weon-Tae Park


    Full Text Available I investigate the vibration and buckling analysis of functionally graded material (FGM structures, using a modified 8-node shell element. The properties of FGM vary continuously through the thickness direction according to the volume fraction of constituents defined by sigmoid function. The modified 8-ANS shell element has been employed to study the effect of power law index on dynamic analysis of FGM plates with various boundary conditions and buckling analysis under combined loads, and interaction curves of FGM plates are carried out. To overcome shear and membrane locking problems, the assumed natural strain method is employed. In order to validate and compare the finite element numerical solutions, the reference results of plates based on Navier’s method, the series solutions of sigmoid FGM (S-FGM plates are compared. Results of the present study show good agreement with the reference results. The solutions of vibration and buckling analysis are numerically illustrated in a number of tables and figures to show the influence of power law index, side-to-thickness ratio, aspect ratio, types of loads, and boundary conditions in FGM structures. This work is relevant to the simulation of wing surfaces, aircrafts, and box structures under various boundary conditions and loadings.

  12. Modelling of interaction between a snow mantle and a flexible structure using a discrete element method

    Directory of Open Access Journals (Sweden)

    F. Nicot


    Full Text Available The search of improvement of protective techniques against natural phenomena such as snow avalanches continues to use classic methods for calculating flexible structures. This paper deals with a new method to design avalanche protection nets. This method is based on a coupled analysis of both net structure and snow mantle by using a Discrete Element Method. This has led to the development of computational software so that avalanche nets can be easily designed. This tool gives the evolution of the forces acting in several parts of the work as a function of the snow situation.

  13. A Finite Element Procedure for Calculating Fluid-Structure Interaction Using MSC/NASTRAN (United States)

    Chargin, Mladen; Gartmeier, Otto


    This report is intended to serve two purposes. The first is to present a survey of the theoretical background of the dynamic interaction between a non-viscid, compressible fluid and an elastic structure is presented. Section one presents a short survey of the application of the finite element method (FEM) to the area of fluid-structure-interaction (FSI). Section two describes the mathematical foundation of the structure and fluid with special emphasis on the fluid. The main steps in establishing the finite element (FE) equations for the fluid structure coupling are discussed in section three. The second purpose is to demonstrate the application of MSC/NASTRAN to the solution of FSI problems. Some specific topics, such as fluid structure analogy, acoustic absorption, and acoustic contribution analysis are described in section four. Section five deals with the organization of the acoustic procedure flowchart. Section six includes the most important information that a user needs for applying the acoustic procedure to practical FSI problems. Beginning with some rules concerning the FE modeling of the coupled system, the NASTRAN USER DECKs for the different steps are described. The goal of section seven is to demonstrate the use of the acoustic procedure with some examples. This demonstration includes an analytic verification of selected FE results. The analytical description considers only some aspects of FSI and is not intended to be mathematically complete. Finally, section 8 presents an application of the acoustic procedure to vehicle interior acoustic analysis with selected results.

  14. New elements in the C-type natriuretic peptide signaling pathway inhibiting swine in vitro oocyte meiotic resumption. (United States)

    Santiquet, Nicolas; Papillon-Dion, Emilie; Djender, Nadjib; Guillemette, Christine; Richard, François J


    C-type natriuretic peptide (CNP) and its cognate receptor, natriuretic peptide receptor (NPR) B, have been shown to promote cGMP production in granulosa/cumulus cells. Once transferred to the oocyte through the gap junctions, the cGMP inhibits oocyte meiotic resumption. CNP has been shown to bind another natriuretic receptor, NPR-C. NPR-C is known to interact with and degrade bound CNP, and has been reported to possess signaling functions. Therefore, NPR-C could participate in the control of oocyte maturation during swine in vitro maturation (IVM). Here, we examine the effect of CNP signaling on meiotic resumption, the amount of cGMP and gap junctional communication (GJC) regulation during swine IVM. The results show an inhibitory effect of CNP in inhibiting oocyte meiotic resumption in follicle-stimulating hormone (FSH)-stimulated IVM. We also found that an NPR-C-specific agonist (cANP([4-23])) is likely to play a role in maintaining meiotic arrest during porcine IVM when in the presence of a suboptimal dose of CNP. Moreover, we show that, even if CNP can increase intracellular concentration of cGMP in cumulus-oocyte complexes, cANP((4-23)) had no impact on cGMP concentration, suggesting a potential cGMP-independent signaling pathway related to NPR-C activation. These data support a potential involvement of cANP((4-23)) through NPR-C in inhibiting oocyte meiotic resumption while in the presence of a suboptimal dose of CNP. The regulation of GJC was not altered by CNP, cANP((4-23)), or the combination of CNP and cANP((4-23)), supporting their potential contribution in sending signals to the oocytes. These findings offer promising insights in to new elements of the signaling pathways that may be involved in inhibiting resumption of meiosis during FSH-stimulated swine IVM. © 2014 by the Society for the Study of Reproduction, Inc.

  15. Modeling of a pulsed fluid column and coupled piping with structural finite elements (United States)

    Saxon, J. B.; Jones, J. U.; Anderson, F. E.


    Structural finite elements have been used to model the coupled fluidic-structural response of a liquid oxygen (LOX) feedline at a rocket engine test facility. The model simulates the effects of Pogo pulsing, a test procedure which uses a piston in a side branch to impart an oscillatory pressure pulse to the LOX column as it feeds the engine. In addition to the feedline's structural characteristics, the model accounts for the mass and axial stiffness of the fluid column, the oscillatory pulse of the piston, and the hydraulic impedance of the rocket engine. The model was used to determine the relations between piston stroke, pressure oscillation at the engine inlet, and structural excitation of the feedline. This paper develops the concepts employed by the model.


    Directory of Open Access Journals (Sweden)

    Petrova Irina Yur’evna


    Full Text Available Subject: automation of calculation of dynamic characteristics of the device being designed in the system of conceptual design of sensor equipment, structurally-parametric models of dynamic processes and algorithms for the automated calculation of the qualitative characteristics of elements of the information-measuring and control systems (IMCS. The stage of conceptual design most fully determines the operational characteristics of technical systems. However, none of the information support systems of this stage provides an opportunity to evaluate the performance characteristics of the element being designed taking into account its dynamic characteristics. Research objectives: increasing the effectiveness of the evaluation of dynamic characteristics of sensitive elements of the information-measuring and control systems of a smart house. Materials and methods: when solving the problems posed, the mathematical apparatus of system modeling was used (in particular, the energy-information method of modeling processes of various physical nature that occur in the sensor equipment; the main provisions of the theory of automatic control, the theory of constructing computer-aided design systems, the theory of operational calculus; basics of conceptual design of elements of the information-measuring and control systems. Results: we compared the known automated systems for conceptual design of sensors, highlighted their advantages and disadvantages and we showed that none of these systems allows us to investigate dynamic characteristics of the element being designed in a simple and understandable for engineer form. The authors proposed using energy-information method of modeling for the synthesis of operation principles of sensors and analysis of their dynamic characteristics. We considered elementary dynamic chains and issues of synthesis of parametrical structural schemes that reflect the dynamics of the process with the use of mathematical apparatus of

  17. Structuring a multi-nodal neural network in vitro within a novel design microfluidic chip. (United States)

    van de Wijdeven, Rosanne; Ramstad, Ola Huse; Bauer, Ulrich Stefan; Halaas, Øyvind; Sandvig, Axel; Sandvig, Ioanna


    Neural network formation is a complex process involving axon outgrowth and guidance. Axon guidance is facilitated by structural and molecular cues from the surrounding microenvironment. Micro-fabrication techniques can be employed to produce microfluidic chips with a highly controlled microenvironment for neural cells enabling longitudinal studies of complex processes associated with network formation. In this work, we demonstrate a novel open microfluidic chip design that encompasses a freely variable number of nodes interconnected by axon-permissible tunnels, enabling structuring of multi-nodal neural networks in vitro. The chip employs a partially open design to allow high level of control and reproducibility of cell seeding, while reducing shear stress on the cells. We show that by culturing dorsal root ganglion cells (DRGs) in our microfluidic chip, we were able to structure a neural network in vitro. These neurons were compartmentalized within six nodes interconnected through axon growth tunnels. Furthermore, we demonstrate the additional benefit of open top design by establishing a 3D neural culture in matrigel and a neuronal aggregate 3D culture within the chips. In conclusion, our results demonstrate a novel microfluidic chip design applicable to structuring complex neural networks in vitro, thus providing a versatile, highly relevant platform for the study of neural network dynamics applicable to developmental and regenerative neuroscience.

  18. The Common Data Elements for Cancer Research: Remarks on Functions and Structure (United States)

    Nadkarni, Prakash M.; Brandt, Cynthia A.


    Objectives The National Cancer Institute (NCI) has developed the Common Data Elements (CDE) to serve as a controlled vocabulary of data descriptors for cancer research, to facilitate data interchange and inter-operability between cancer research centers. We evaluated CDE’s structure to see whether it could represent the elements necessary to support its intended purpose, and whether it could prevent errors and inconsistencies from being accidentally introduced. We also performed automated checks for certain types of content errors that provided a rough measure of curation quality. Methods Evaluation was performed on CDE content downloaded via the NCI’s CDE Browser, and transformed into relational database form. Evaluation was performed under three categories: 1) compatibility with the ISO/IEC 11179 metadata model, on which CDE structure is based, 2) features necessary for controlled vocabulary support, and 3) support for a stated NCI goal, set up of data collection forms for cancer research. Results Various limitations were identified both with respect to content (inconsistency, insufficient definition of elements, redundancy) as well as structure – particularly the need for term and relationship support, as well as the need for metadata supporting the explicit representation of electronic forms that utilize sets of common data elements. Conclusions While there are numerous positive aspects to the CDE effort, there is considerable opportunity for improvement. Our recommendations include review of existing content by diverse experts in the cancer community; integration with the NCI thesaurus to take advantage of the latter’s links to nationally used controlled vocabularies, and various schema enhancements required for electronic form support. PMID:17149500

  19. Finite element prediction of seismic response modification of monumental structures utilizing base isolation (United States)

    Spanos, Konstantinos; Anifantis, Nikolaos; Kakavas, Panayiotis


    The analysis of the mechanical behavior of ancient structures is an essential engineering task concerning the preservation of architectural heritage. As many monuments of classical antiquity are located in regions of earthquake activity, the safety assessment of these structures, as well as the selection of possible restoration interventions, requires numerical models capable of correctly representing their seismic response. The work presented herein was part of a research project in which a better understanding of the dynamics of classical column-architrave structures was sought by means of numerical techniques. In this paper, the seismic behavior of ancient monumental structures with multi-drum classical columns is investigated. In particular, the column-architrave classical structure under strong ground excitations was represented by a finite element method. This approach simulates the individual rock blocks as distinct rigid blocks interconnected with slidelines and incorporates seismic isolation dampers under the basement of the structure. Sliding and rocking motions of individual stone blocks and drums are modeled utilizing non-linear frictional contact conditions. The seismic isolation is modeled through the application of pad bearings under the basement of the structure. These pads are interpreted by appropriate rubber and steel layers. Time domain analyses were performed, considering the geometric and material non-linear behavior at the joints and the characteristics of pad bearings. The deformation and failure modes of drum columns subject to seismic excitations of various types and intensities were analyzed. The adverse influence of drum imperfections on structural safety was also examined.

  20. Structural relationships between highly conserved elements and genes in vertebrate genomes.

    Directory of Open Access Journals (Sweden)

    Hong Sun

    Full Text Available Large numbers of sequence elements have been identified to be highly conserved among vertebrate genomes. These highly conserved elements (HCEs are often located in or around genes that are involved in transcription regulation and early development. They have been shown to be involved in cis-regulatory activities through both in vivo and additional computational studies. We have investigated the structural relationships between such elements and genes in six vertebrate genomes human, mouse, rat, chicken, zebrafish and tetraodon and detected several thousand cases of conserved HCE-gene associations, and also cases of HCEs with no common target genes. A few examples underscore the potential significance of our findings about several individual genes. We found that the conserved association between HCE/HCEs and gene/genes are not restricted to elements by their absolute distance on the genome. Notably, long-range associations were identified and the molecular functions of the associated genes do not show any particular overrepresentation of the functional categories previously reported. HCEs in close proximity are found to be linked with different set of gene/genes. The results reflect the highly complex correlation between HCEs and their putative target genes.

  1. Effects of implant tilting and the loading direction on the displacement and micromotion of immediately loaded implants: an in vitro experiment and finite element analysis (United States)


    Purpose The purpose of this study was to investigate the effects of implant tilting and the loading direction on the displacement and micromotion (relative displacement between the implant and bone) of immediately loaded implants by in vitro experiments and finite element analysis (FEA). Methods Six artificial bone blocks were prepared. Six screw-type implants with a length of 10 mm and diameter of 4.3 mm were placed, with 3 positioned axially and 3 tilted. The tilted implants were 30° distally inclined to the axial implants. Vertical and mesiodistal oblique (45° angle) loads of 200 N were applied to the top of the abutment, and the abutment displacement was recorded. Nonlinear finite element models simulating the in vitro experiment were constructed, and the abutment displacement and micromotion were calculated. The data on the abutment displacement from in vitro experiments and FEA were compared, and the validity of the finite element model was evaluated. Results The abutment displacement was greater under oblique loading than under axial loading and greater for the tilted implants than for the axial implants. The in vitro and FEA results showed satisfactory consistency. The maximum micromotion was 2.8- to 4.1-fold higher under oblique loading than under vertical loading. The maximum micromotion values in the axial and tilted implants were very close under vertical loading. However, in the tilted implant model, the maximum micromotion was 38.7% less than in the axial implant model under oblique loading. The relationship between abutment displacement and micromotion varied according to the loading direction (vertical or oblique) as well as the implant insertion angle (axial or tilted). Conclusions Tilted implants may have a lower maximum extent of micromotion than axial implants under mesiodistal oblique loading. The maximum micromotion values were strongly influenced by the loading direction. The maximum micromotion values did not reflect the abutment

  2. Validating finite element models of composite aerospace structures for damage detection applications (United States)

    Oliver, J. A.; Kosmatka, J. B.; Hemez, François M.; Farrar, Charles R.


    Carbon-fiber-reinforced-polymer (CFRP) composites represent the future for advanced lightweight aerospace structures. However, reliable and cost-effective techniques for structural health monitoring (SHM) are needed. Modal and vibration-based analysis, when combined with validated finite element (FE) models, can provide a key tool for SHM. Finite element models, however, can easily give spurious and misleading results if not finely tuned and validated. These problems are amplified in complex structures with numerous joints and interfaces. A small series of all-composite test pieces emulating wings from a lightweight all-composite Unmanned Aerial Vehicle (UAV) have been developed to support damage detection and SHM research. Each wing comprises two CFRP prepreg and Nomex honeycomb co-cured skins and two CFRP prepreg spars bonded together in a secondary process using a structural adhesive to form the complete wings. The first of the set is fully healthy while the rest have damage in the form of disbonds built into the main spar-skin bondline. Detailed FE models were created of the four structural components and the assembled structure. Each wing component piece was subjected to modal characterization via vibration testing using a shaker and scanning laser Doppler vibrometer before assembly. These results were then used to correlate the FE model on a component-basis, through fitting and optimization of polynomial meta-models. Assembling and testing the full wing provided subsequent data that was used to validate the numerical model of the entire structure, assembled from the correlated component models. The correlation process led to the following average percent improvement between experimental and FE frequencies of the first 20 modes for each piece: top skin 10.98%, bottom skin 45.62%, main spar 25.56%, aft spar 10.79%. The assembled wing model with no further correlation showed an improvement of 32.60%.

  3. The structure of a rigorously conserved RNA element within the SARS virus genome.

    Directory of Open Access Journals (Sweden)

    Michael P Robertson


    Full Text Available We have solved the three-dimensional crystal structure of the stem-loop II motif (s2m RNA element of the SARS virus genome to 2.7-A resolution. SARS and related coronaviruses and astroviruses all possess a motif at the 3' end of their RNA genomes, called the s2m, whose pathogenic importance is inferred from its rigorous sequence conservation in an otherwise rapidly mutable RNA genome. We find that this extreme conservation is clearly explained by the requirement to form a highly structured RNA whose unique tertiary structure includes a sharp 90 degrees kink of the helix axis and several novel longer-range tertiary interactions. The tertiary base interactions create a tunnel that runs perpendicular to the main helical axis whose interior is negatively charged and binds two magnesium ions. These unusual features likely form interaction surfaces with conserved host cell components or other reactive sites required for virus function. Based on its conservation in viral pathogen genomes and its absence in the human genome, we suggest that these unusual structural features in the s2m RNA element are attractive targets for the design of anti-viral therapeutic agents. Structural genomics has sought to deduce protein function based on three-dimensional homology. Here we have extended this approach to RNA by proposing potential functions for a rigorously conserved set of RNA tertiary structural interactions that occur within the SARS RNA genome itself. Based on tertiary structural comparisons, we propose the s2m RNA binds one or more proteins possessing an oligomer-binding-like fold, and we suggest a possible mechanism for SARS viral RNA hijacking of host protein synthesis, both based upon observed s2m RNA macromolecular mimicry of a relevant ribosomal RNA fold.

  4. Effect of Superficial Atmospheric Corrosion Upon the Internal Stresses in Structural Steel Elements

    Directory of Open Access Journals (Sweden)

    Monel Leiba


    Full Text Available A research program is presented showing the stress status determined by the corrosion phenomenon inside a specimen of a structural steel element. Several stains are studied their diameters ranging from 1~mm to 6~mm and thickness of the corroded layer under 0.5~mm. The physical modeling is the result of testing in laboratory the phenomenon of superficial atmospheric corrosion and the numerical modeling was developed under a FEM program, ALGOR. A number of 3,200 finite elements of BRICK type were created and the evolution of normal and tangential stresses was scrutinized under the process of loosing elementary material transformed into scrap. Stresses in the damaged sphere were graphically put into evidence and determined with accuracy due to the performances of the program, showing the local perturbations and the pattern of stress concentrators. The studies showed the importance of reproducing with both physical and mathematical methods the intricate mechanism and sometimes unpredictable effects of corrosion phenomenon upon the structural steel elements.

  5. Response of Basic Structural Elements and B-52 Structural Components to Simulated Nuclear Overpressure. Volume I-Program Description and Results (Basic Structural Elements) (United States)


    determining the response of high-frequency structural components, such as aircraft skin panels, stringers, frames and radomes. As a result of the moratorium ...5) 00 C\\1 co a u- Cj 0 V) w CD -) (D - ~LLJO( 4-3 COD ) Ci Il 02 0 S-i 61 LL. 41) 05C LLI- <w C3 Co 0C 0l I-0 M- u cX< I- Z CD - Li -::I C.D 0 X: LLI

  6. Structural damage detection using higher-order finite elements and a scanning laser vibrometer (United States)

    Jin, Si

    In contrast to conventional non-destructive evaluation methods, dynamics-based damage detection methods are capable of rapid integrity evaluation of large structures and have received considerable attention from aerospace, mechanical, and civil engineering communities in recent years. However, the identifiable damage size using dynamics-based methods is determined by the number of sensors used, level of measurement noise, accuracy of structural models, and signal processing techniques. In this thesis we study dynamics of structures with damage and then derive and experimentally verify new model-independent structural damage detection methods that can locate small damage to structures. To find sensitive damage detection parameters we develop a higher-order beam element that enforces the continuity of displacements, slopes, bending moments, and shear forces at all nodes, and a higher-order rectangular plate element that enforces the continuity of displacements, slopes, and bending and twisting moments at all nodes. These two elements are used to study the dynamics of beams and plates. Results show that high-order spatial derivatives of high-frequency modes are important sensitive parameters that can locate small structural damage. Unfortunately the most powerful and popular structural modeling technique, the finite element method, is not accurate in predicting high-frequency responses. Hence, a model-independent method using dynamic responses obtained from high density measurements is concluded to be the best approach. To increase measurement density and reduce noise a Polytec PI PSV-200 scanning laser vibrometer is used to provide non-contact, dense, and accurate measurements of structural vibration velocities. To avoid the use of structural models and to extract sensitive detection parameters from experimental data, a brand-new structural damage detection method named BED (Boundary-Effect Detection) is developed for pinpointing damage locations using Operational

  7. Techniques for modeling muscle-induced forces in finite element models of skeletal structures. (United States)

    Grosse, Ian R; Dumont, Elizabeth R; Coletta, Chris; Tolleson, Alex


    This work introduces two mechanics-based approaches to modeling muscle forces exerted on curvilinear bone structures and compares the results with two traditional ad hoc methods of muscle loading. These new models use a combination of tensile, tangential, and normal traction loads to account for muscle fibers wrapped around curved bone surfaces. A computer program was written to interface with a commercial finite element analysis tool to automatically apply traction loads to surface faces of elements in muscle attachment regions according to the various muscle modeling methods. We modeled a highly complex skeletal structure, the skull of a Jamaican fruit bat (Artibeus jamaicensis), to compare the four muscle-loading methods. While reasonable qualitative agreement was found in the states of stress of the skull between the four muscle load modeling methods, there were substantial quantitative differences predicted in the stress states in some high stressed regions of the skull. Furthermore, our mechanics-based models required significantly less total applied muscle force to generate a bite-point reaction force identical to those produced by the ad hoc muscle loading models. Although the methods are not validated by in vivo data, we submit that muscle-load modeling methods that account for the underlying physics of muscle wrapping on curved bone surfaces are likely to provide more realistic results than ad hoc approaches that do not. We also note that, due to the geometric complexity of many bone structures--such as the skull analyzed here--load transmission paths are difficult to conceptualize a priori. Consequently, it is difficult to predict spatially where the results of finite element analyses are likely to be compromised by using ad hoc muscle modeling methods. For these reasons, it is recommended that a mechanics-based method be adopted for determination of the proper traction loads to be applied to skeletal structures due to muscular activity. Copyright 2007

  8. Element Decoupling of 7T Dipole Body Arrays by EBG Metasurface Structures: Experimental Verification

    CERN Document Server

    Hurshkainen, Anna A; Glybovski, Stanislav B; Voogt, Ingmar J; Melchakova, Irina V; Berg, Cornelis A T van den; Raaijmakers, Alexander J E


    Metasurfaces are artificial electromagnetic boundaries or interfaces usually implemented as two-dimensional periodic structures with subwavelength periodicity and engineered properties of constituent unit cells. The electromagnetic bandgap (EBG) effect in metasurfaces prevents all surface modes from propagating in a certain frequency band. While metasurfaces provide a number of important applications in microwave antennas and antenna arrays, their features are also highly suitable for MRI applications. In this work we manufacture and experimentally study finite samples based on mushroom-type EBG metasurfaces and employ them for suppression of inter-element coupling in dipole transmit coil arrays for body imaging at 7T. We show experimentally that employment of the samples EBG leads to reduction of coupling between adjacent closely-spaced dipole antenna elements of a 7T transmit/receive body array, which reduces scattering losses in neighboring channels and thereby improves the B1+ efficiency. The setup consis...

  9. Comb structure analysis of the capacitive sensitive element in MEMS-accelerometer (United States)

    Shalimov, Andrew; Timoshenkov, Sergey; Korobova, Natalia; Golovinskiy, Maxim; Timoshenkov, Alexey; Zuev, Egor; Berezueva, Svetlana; Kosolapov, Andrey


    In this paper analysis of comb design for the sensing element MEMS accelerometer with longitudinal displacement of the inertial mass under the influence of acceleration to obtain the necessary parameters for the further construction of an electronic circuit for removal and signal processing has been done. Fixed on the stator the inertia mass has the ability to move under the influence of acceleration along the longitudinal structure. As a result the distance between the fixed and movable combs, and hence the capacitance in the capacitors have been changed. Measuring the difference of these capacitances you can estimate the value of the applied acceleration. Furthermore, managing combs that should apply an electrostatic force for artificial deviation of the inertial mass may be used for the initial sensitive elements culling. Also in this case there is a change of capacitances, which can be measured by the comb and make a decision about the spoilage presence or absence.

  10. Finite-element-model updating using computational intelligence techniques applications to structural dynamics

    CERN Document Server

    Marwala, Tshilidzi


    Finite element models (FEMs) are widely used to understand the dynamic behaviour of various systems. FEM updating allows FEMs to be tuned better to reflect measured data and may be conducted using two different statistical frameworks: the maximum likelihood approach and Bayesian approaches. Finite Element Model Updating Using Computational Intelligence Techniques applies both strategies to the field of structural mechanics, an area vital for aerospace, civil and mechanical engineering. Vibration data is used for the updating process. Following an introduction a number of computational intelligence techniques to facilitate the updating process are proposed; they include: • multi-layer perceptron neural networks for real-time FEM updating; • particle swarm and genetic-algorithm-based optimization methods to accommodate the demands of global versus local optimization models; • simulated annealing to put the methodologies into a sound statistical basis; and • response surface methods and expectation m...

  11. Finite Element Reliability Analysis of Chloride Ingress into Reinforced Concrete Structures

    DEFF Research Database (Denmark)

    Frier, Christian; Sørensen, John Dalsgaard


    For many reinforced concrete structures corrosion of the reinforcement is an important problem since it can result in maintenance and repair actions. Further, a reduction of the load-bearing capacity can occur. In the present paper the Finite Element Reliability Method (FERM) is employed...... for obtaining the probability of exceeding a critical chloride concentration level at the reinforcement bars, both using Monte Carlo Simulation (MCS) and the First Order Reliability Method (FORM). The chloride ingress is modelled by the Finite Element Method (FEM) and the diffusion coefficient, surface chloride...... concentration and reinforcement cover depth are modelled by stochastic fields, which are discretized using the Expansion Optimum Linear Estimation (EOLE) approach. The response gradients needed for FORM analysis are derived analytically using the Direct Differentiation Method (DDM). As an example, a bridge pier...

  12. Electronic structure of eka-thorium (element 122) compared with thorium

    Energy Technology Data Exchange (ETDEWEB)

    Eliav, Ephraim; Landau, Arie; Kaldor, Uzi [School of Chemistry, Tel Aviv University, Tel Aviv (Israel)]. E-mail:; Ishikawa, Yasuyuki [Department of Chemistry, University of Puerto Rico, San Juan, Puerto Rico (United States)


    The electronic levels of thorium and eka-thorium (element 122) are calculated in the framework of the Dirac-Coulomb-Breit Hamiltonian using a large Gaussian-spinor basis. Correlation is included by the Fock-space or intermediate Hamiltonian coupled-cluster method. The 51 reported levels of thorium and its ions are compared with experiment, giving an average error of 0.062 V for Fock space and 0.051 V for the intermediate Hamiltonian method. Predicted E122 levels are expected to have similar accuracy. The ground state of E122 is 8s{sup 2}7d8p, to be contrasted with 7s{sup 2}6d{sup 2} for Th. Increased relativistic effects in the super-heavy element lead to major differences between the level structure of these two atoms and their ions. The effects of Breit and QED terms are discussed. (author)

  13. Investigation of the two-element airfoil with flap structure for the vertical axis wind turbine (United States)

    Wei, Y.; Li, C.


    The aerodynamic performance of Vertical axis wind turbine (VAWT) is not as simple as its structure because of the large changing range of angle of attack. We have designed a new kind of two-element airfoil for VAWT on the basis of NACA0012. CFD calculation has been confirmed to have high accuracy by comparison with the experiment data and Xfoil result. The aerodynamic parameter of two-element airfoil has been acquired by CFD calculation in using the Spalart-Allmaras (S-A) turbulence model and the Simple scheme. The relationship between changings of angle of attack and flap's tilt angle has been found and quantified. The analysis will lay the foundation for further research on the control method for VAWT.

  14. Structural changes of high-amylose rice starch residues following in vitro and in vivo digestion. (United States)

    Man, Jianmin; Yang, Yang; Zhang, Changquan; Zhou, Xinghua; Dong, Ying; Zhang, Fengmin; Liu, Qiaoquan; Wei, Cunxu


    High-amylose cereal starch has a great benefit on human health through its resistant starch content. In this paper, starches were isolated from mature grains of high-amylose transgenic rice line (TRS) and its wild-type rice cultivar Te-qing (TQ) and digested in vitro and in vivo. The structural changes of digestive starch residues were characterized using DSC, XRD, (13)C CP/MAS NMR, and ATR-FTIR. TQ starch was very susceptible to digestion; its residues following in vitro and in vivo digestion showed similar structural characteristics with TQ control starch, which suggested that both amorphous and crystalline structures were simultaneously digested. Both amorphous and the long-range order structures were also simultaneously hydrolyzed in TRS starch, but the short-range order (double helix) structure in the external region of TRS starch granule increased with increasing digestion time. The A-type polymorph of TRS C-type starch was hydrolyzed more rapidly than the B-type polymorph. These results suggested that B-type crystallinity and short-range order structure in the external region of starch granule made TRS starch resistant to digestion.

  15. Structural evolution of Ni-20Cr alloy during ball milling of elemental powders

    Energy Technology Data Exchange (ETDEWEB)

    Lopez B, I.; Trapaga M, L. G. [IPN, Centro de Investigacion y de Estudios Avanzados, Unidad Queretaro, Libramiento Norponiente No. 2000, Juriquilla, 76230 Queretaro (Mexico); Martinez F, E. [Centro de Investigacion e Innovacion Tecnologica, Cerrada de Cecati s/n, Col. Santa Catarina Azcapotzalco, 02250 Mexico D. F. (Mexico); Zoz, H., E-mail: [Zoz GmbH, D-57482, Wenden (Germany)


    The ball milling (B M) of blended Ni and Cr elemental powders was carried out in a Simoloyer performing on high-energy scale mode at maximum production to obtain a nano structured Ni-20Cr alloy. The phase transformations and structural changes occurring during mechanical alloying were investigated by X-ray diffraction (XRD) and optical microscopy (Om). A gradual solid solubility of Cr and the subsequent formation of crystalline metastable solid solutions described in terms of the Avrami-Ero fe ev kinetics model were calculated. The XRD analysis of the structure indicates that cumulative lattice strain contributes to the driving force for solid solution between Ni and Cr during B M. Microstructure evolution has shown, additionally to the lamellar length refinement commonly observed, the folding of lamellae in the final processing stage. Om observations revealed that the lamellar spacing of Ni rich zones reaches a steady value near 500 nm and almost disappears after 30 h of milling. (Author)

  16. A finite element-analytical method for modeling a structure in an infinite fluid (United States)

    Zarda, P. R.


    A method is described from which the interaction of an elastic structure with an infinite acoustic fluid is determined. The displacements of the structure and the pressure field of the immediate surrounding fluid are modeled by finite elements, and the remaining pressure field of the infinite fluid region is given by an analytical expression. This method yields a frequency dependent boundary condition for the outer fluid boundary when applied to the frequency response of an elastic beam in contact with an acoustic fluid. The frequency response of the beam is determined using NASTRAN, and compares favorably to the exact solution which is also presented. The effect of the fluid on the response of the structure at low and high frequencies is due to added mass and damping characteristics, respectively.

  17. Technical note on using CNTs as reinforcements in reinforced concrete structural elements (United States)

    Babu, C. Ramesh


    The disasters whether man made or natural dominates all types of structures and has ever been attention to researchers, academicians and scientists. Concrete had been reinforced with steel, macro fibers and microfibers which bridges the cracks. The advantages of microfibers are to delay the development of cracks. Numerous researches focused on arresting the initiation of micro cracks and delay in the macro cracks. However the initiation of the cracks could not be avoided. It is quite fruitful and needy for the present scenario in a country like India to carry out research by reinforcing concrete with fibers/nanomaterials at nano scale which would provide crack free materials and structures. This technical note explores the possibilities of impregnating concrete with CNTs (Carbon Nano Tubes) and also as reinforcement bars at macro level in reinforced concrete structural elements.

  18. Polymorphism in elemental silicon: Probabilistic interpretation of the realizability of metastable structures (United States)

    Jones, Eric B.; Stevanović, Vladan


    With few systems of technological interest having been studied as extensively as elemental silicon, there currently exists a wide disparity between the number of predicted low-energy silicon polymorphs and those that have been experimentally realized as metastable at ambient conditions. We put forward an explanation for this disparity wherein the likelihood of formation of a given polymorph under near-equilibrium conditions can be estimated on the basis of mean-field isothermal-isobaric (N ,p ,T ) ensemble statistics. The probability that a polymorph will be experimentally realized is shown to depend upon both the hypervolume of that structure's potential energy basin of attraction and a Boltzmann factor weight containing the polymorph's potential enthalpy per particle. Both attributes are calculated using density functional theory relaxations of randomly generated initial structures. We find that the metastable polymorphism displayed by silicon can be accounted for using this framework to the exclusion of a very large number of other low-energy structures.

  19. Structure and Expression Analyses of SVA Elements in Relation to Functional Genes

    Directory of Open Access Journals (Sweden)

    Yun-Jeong Kwon


    Full Text Available SINE-VNTR-Alu (SVA elements are present in hominoid primates and are divided into 6 subfamilies (SVA-A to SVA-F and active in the human population. Using a bioinformatic tool, 22 SVA element-associated genes are identified in the human genome. In an analysis of genomic structure, SVA elements are detected in the 5' untranslated region (UTR of HGSNAT (SVA-B, MRGPRX3 (SVA-D, HYAL1 (SVA-F, TCHH (SVA-F, and ATXN2L (SVA-F genes, while some elements are observed in the 3'UTR of SPICE1 (SVA-B, TDRKH (SVA-C, GOSR1 (SVA-D, BBS5 (SVA-D, NEK5 (SVA-D, ABHD2 (SVA-F, C1QTNF7 (SVA-F, ORC6L (SVA-F, TMEM69 (SVA-F, and CCDC137 (SVA-F genes. They could contribute to exon extension or supplying poly A signals. LEPR (SVA-C, ALOX5 (SVA-D, PDS5B (SVA-D, and ABCA10 (SVA-F genes also showed alternative transcripts by SVA exonization events. Dominant expression of HYAL1_SVA appeared in lung tissues, while HYAL1_noSVA showed ubiquitous expression in various human tissues. Expression of both transcripts (TDRKH_SVA and TDRKH_noSVA of the TDRKH gene appeared to be ubiquitous. Taken together, these data suggest that SVA elements cause transcript isoforms that contribute to modulation of gene regulation in various human tissues.

  20. Structure and Expression Analyses of SVA Elements in Relation to Functional Genes. (United States)

    Kwon, Yun-Jeong; Choi, Yuri; Eo, Jungwoo; Noh, Yu-Na; Gim, Jeong-An; Jung, Yi-Deun; Lee, Ja-Rang; Kim, Heui-Soo


    SINE-VNTR-Alu (SVA) elements are present in hominoid primates and are divided into 6 subfamilies (SVA-A to SVA-F) and active in the human population. Using a bioinformatic tool, 22 SVA element-associated genes are identified in the human genome. In an analysis of genomic structure, SVA elements are detected in the 5' untranslated region (UTR) of HGSNAT (SVA-B), MRGPRX3 (SVA-D), HYAL1 (SVA-F), TCHH (SVA-F), and ATXN2L (SVA-F) genes, while some elements are observed in the 3'UTR of SPICE1 (SVA-B), TDRKH (SVA-C), GOSR1 (SVA-D), BBS5 (SVA-D), NEK5 (SVA-D), ABHD2 (SVA-F), C1QTNF7 (SVA-F), ORC6L (SVA-F), TMEM69 (SVA-F), and CCDC137 (SVA-F) genes. They could contribute to exon extension or supplying poly A signals. LEPR (SVA-C), ALOX5 (SVA-D), PDS5B (SVA-D), and ABCA10 (SVA-F) genes also showed alternative transcripts by SVA exonization events. Dominant expression of HYAL1_SVA appeared in lung tissues, while HYAL1_noSVA showed ubiquitous expression in various human tissues. Expression of both transcripts (TDRKH_SVA and TDRKH_noSVA) of the TDRKH gene appeared to be ubiquitous. Taken together, these data suggest that SVA elements cause transcript isoforms that contribute to modulation of gene regulation in various human tissues.

  1. Impact of the Mathematical Model Description on the Assessment of the Reliability of Structural Elements (United States)

    Dudzik, Agnieszka


    The study presents a probabilistic approach to the problems of static analysis of structural elements. A steel and reinforced concrete elements were analysed. Structural design parameters were defined as deterministic values and random variables. The latter were not correlated. The criterion of structural failure is expressed by limit functions related to the ultimate limit state. In the performed analyses explicit form of the random variables function were used. The Hasofer-Lind index was used as a reliability measure. In the description of random variables were used the different types of probability distribution appropriate to the nature of the variable. Sensitivity of reliability index to the random variables was defined. If the reliability index sensitivity due to the random variable Xi is low when compared with other variables, it can be stated that the impact of this variable on failure probability is small. Therefore, in successive computations it can be treated as a deterministic parameter. Sensitivity analysis leads to simplify the description of the mathematical model, determine the new limit functions and values of the Hasofer-Lind reliability index. Besides the effect of the assumed level of the variation coefficient of selected random variables on value of the reliability index was determined. The primary research method is the FORM method. In order to verify the correctness of the calculation SORM, Monte Carlo and Importance Sampling methods were used. In the examples of reliability analysis the NUMPRESS program was used. In the considered issues the time was not taken into account explicitly.

  2. Application of the Recursive Finite Element Approach on 2D Periodic Structures under Harmonic Vibrations

    Directory of Open Access Journals (Sweden)

    Reem Yassine


    Full Text Available The frequency response function is a quantitative measure used in structural analysis and engineering design; hence, it is targeted for accuracy. For a large structure, a high number of substructures, also called cells, must be considered, which will lead to a high amount of computational time. In this paper, the recursive method, a finite element method, is used for computing the frequency response function, independent of the number of cells with much lesser time costs. The fundamental principle is eliminating the internal degrees of freedom that are at the interface between a cell and its succeeding one. The method is applied solely for free (no load nodes. Based on the boundary and interior degrees of freedom, the global dynamic stiffness matrix is computed by means of products and inverses resulting with a dimension the same as that for one cell. The recursive method is demonstrated on periodic structures (cranes and buildings under harmonic vibrations. The method yielded a satisfying time decrease with a maximum time ratio of 1 18 and a percentage difference of 19%, in comparison with the conventional finite element method. Close values were attained at low and very high frequencies; the analysis is supported for two types of materials (steel and plastic. The method maintained its efficiency with a high number of forces, excluding the case when all of the nodes are under loads.

  3. Analysis of secondary structural elements in human microRNA hairpin precursors. (United States)

    Liu, Biao; Childs-Disney, Jessica L; Znosko, Brent M; Wang, Dan; Fallahi, Mohammad; Gallo, Steven M; Disney, Matthew D


    MicroRNAs (miRNAs) regulate gene expression by targeting complementary mRNAs for destruction or translational repression. Aberrant expression of miRNAs has been associated with various diseases including cancer, thus making them interesting therapeutic targets. The composite of secondary structural elements that comprise miRNAs could aid the design of small molecules that modulate their function. We analyzed the secondary structural elements, or motifs, present in all human miRNA hairpin precursors and compared them to highly expressed human RNAs with known structures and other RNAs from various organisms. Amongst human miRNAs, there are 3808 are unique motifs, many residing in processing sites. Further, we identified motifs in miRNAs that are not present in other highly expressed human RNAs, desirable targets for small molecules. MiRNA motifs were incorporated into a searchable database that is freely available. We also analyzed the most frequently occurring bulges and internal loops for each RNA class and found that the smallest loops possible prevail. However, the distribution of loops and the preferred closing base pairs were unique to each class. Collectively, we have completed a broad survey of motifs found in human miRNA precursors, highly expressed human RNAs, and RNAs from other organisms. Interestingly, unique motifs were identified in human miRNA processing sites, binding to which could inhibit miRNA maturation and hence function.

  4. Fatigue assessment for selected connections of structural steel bridge components using the finite elements method (United States)

    Śledziewski, Krzysztof


    Material fatigue it is one of the most frequent causes of steel bridge failures, particularly the bridges already existing. Thus, the procedure of fatigue life assessment is one of the most relevant procedures in a comprehensive assessment of load-carrying capacity and service life of the structure. A reliable assessment of the fatigue life is predominantly decisive for estimation of the remaining service life. Hitherto, calculation methods of welded joints took into account only stresses occurring in cross sections of whole elements and did not take into account stress concentration occurring in the vicinity of the weld, caused by geometrical aspects of the detail. At present, use of the Finite Element Analysis, makes possible looking for more accurate approach to the fatigue design of steel structures. The method of geometrical stresses is just such approach which is based on definition of stresses which take into account geometry of the detail. The study presents fatigue assessment of a representative type of welded joint in welded bridge structures. The testing covered longitudinal attachments. The main analyses were carried out on the basis of FEM and the method of local stresses, so-called "hot-spot" stresses. The obtained values of stresses were compared with the values obtained in accordance with the method of nominal stress.

  5. Structural-acoustic finite element analysis of the automobile passenger compartment: A review of current practice (United States)

    Nefske, D. J.; Wolf, J. A.; Howell, L. J.


    This paper contains a brief review of the formulation of the finite element method for structural-acoustic analysis of an enclosed cavity, and illustrations are given of the application of this analytical method at General Motors Corporation to investigate the acoustics of the automobile passenger compartment. Low frequency noise in the passenger compartment (in approximately the 20-200 Hz frequency range) is of primary interest, and particularly that noise which is generated by the structural vibration of the wall panels of the compartment. The topics which are covered in the paper include the computation of acoustic modes and resonant frequencies of the passenger compartment, the effect of flexible wall panels on the cavity acoustics, the methods of direct and modal coupling of the structural and acoustic vehicle systems, and forced vibration analysis illustrating the techniques for computing panel-excited noise and for identifying critical panels around the passenger compartment. The capabilities of the finite element method are illustrated by applications to the production automobile, and experimental verifications of the various techniques are presented to illustrate the accuracy of the method.

  6. Finite Element Analysis and Lightweight Optimization Design on Main Frame Structure of Large Electrostatic Precipitator

    Directory of Open Access Journals (Sweden)

    Xuewen Wang


    Full Text Available The geometric modeling and finite element modeling of the whole structure of an electrostatic precipitator and its main components consisting of top beam, column, bottom beam, and bracket were finished. The strength calculation was completed. As a result, the design of the whole structure of the electrostatic precipitator and the main components were reasonable, the structure was in a balance state, its working condition was safe and reliable, its stress variation was even, and the stress distribution was regular. The maximum von Mises stress of the whole structure is 20.14 MPa. The safety factor was large, resulting in a waste of material. An optimization mathematical model is established. Using the ANSYS first-order method, the dimension parameters of the main frame structure of the electrostatic precipitator were optimized. After optimization, more reasonable structural design parameters were obtained. The model weight is 72,344.11 kg, the optimal weight is 49,239.35 kg, and the revised weight is 53,645.68 kg. Compared with the model weight, the optimal weight decreased by 23,104.76 kg and the objective function decreased by 31.94%, while the revised weight decreased by 18,698.43 kg and the objective function decreased by 25.84%.

  7. Structural behavior of SC panel subjected to impact loading using finite element analysis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyuk-Kee; Kim, Seung-Eock, E-mail:


    Highlights: • Structural behavior of SC panel subjected to impact loading is evaluated using numerical analysis. • Sensitivity studies according to fracture energy and erosion value are performed. • Analysis results are compared with impact test for SC panel. - Abstract: After the terrorist attack on the World Trade Center using aircraft in New York City in 2001, safety assessments of nuclear power plant (NPP) structures subjected to impact loading have been actively performed. Since impact tests are possible for small-scale structures but not for full-scale structures, finite element (FE) analysis is necessary for a safety assessment of NPP structure. Analysis factors such as the material model of concrete and steel, strain rate effect, concrete fracture energy, and erosion value influence the analysis results. In this paper, the effect of the concrete fracture energy and the erosion in the material model of a steel-plate concrete (SC) panel subjected to the impact loading is evaluated using the commercial software LS-DYNA. The analysis results are compared with the impact test for an SC panel conducted in other research. A quarter model of an SC panel is adopted for impact analysis. The impact force–time history is applied on the SC panel. Sensitivity studies according to the fracture energy and the erosion value are performed in order to evaluate the structural behavior of SC panels.

  8. Modeling Concrete Material Structure: A Two-Phase Meso Finite Element Model (United States)

    Bonifaz, E. A.; Baus, Juan; Lantsoght, Eva O. L.

    Concrete is a compound material where aggregates are randomly placed within the cement paste. To describe the behavior of concrete structures at the ultimate, it is necessary to use nonlinear finite element models, which for shear and torsion problems do not always give satisfactory results. The current study aims at improving the modeling of concrete at the meso-level, which eventually can result in an improved assessment of existing structures. Concrete as a heterogeneous material is modeled consisting of hydrated cement paste and aggregates. The stress-strain curves of the hydrated cement paste and aggregates are described with results from the literature. A three-dimensional (3D) finite element model was developed to determine the influence of individual phases on the inelastic stress-strain distribution of concrete structures. A random distribution and morphology of the cement and aggregate fractions are achieved by using DREAM.3D. Two affordable computational dual-phase representative volume elements (RVEs) are imported to ABAQUS to be studied in compression and tension. The virtual specimens (concrete mesh) subjected to continuous monotonic strain loading conditions were constrained with 3D boundary conditions. Results demonstrate differences in stress-strain mechanical behavior in both compression and tension test simulations. A strong dependency of flow stress and plastic strain on phase type, aggregate (andesite) size, shape and distribution upon the composite local response are clearly observed. It is noted that the resistance to flow is higher in concrete meshes composed of finer and homogeneous aggregate particles because the Misses stresses and effective plastic strains are better distributed. This study shows that at the meso-level, concrete can be modeled consisting of aggregates and hydrated cement paste.

  9. Development of an Image Fringe Zero Selection System for Structuring Elements with Stereo Vision Disparity Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Grindley, Josef E; Jiang Lin; Tickle, Andrew J, E-mail:, E-mail: [School of Electrical Engineering, Electronics and Computer Science, University of Liverpool, Liverpool L69 3GJ (United Kingdom)


    When performing image operations involving Structuring Element (SE) and many transforms it is required that the outside of the image be padded with zeros or ones depending on the operation. This paper details how this can be achieved with simulated hardware using DSP Builder in Matlab with the intention of migrating the design to HDL (Hardware Description Language) and implemented on an FPGA (Field Programmable Gate Array). The design takes few resources and does not require extra memory to account for the change in size of the output image.


    Directory of Open Access Journals (Sweden)



    Full Text Available In modern conditions of social development, changes in land eco-system of economic relations in Ukraine, the problem of providing conditions for the creation of sustainable land use and creation of protected areas get the status of special urgency. Ideology establishment of ecological networks became logical continuation of environmental thought in general. Considering the methodological approach to the establishment of ecological networks we can constitute, that it is an environmental frame of spatial infrastructure, land conservation and environmental areas, major part of land is the basis of the structural elements of ecological network. Designing an ecological network is made through developing regional schemes of Econet formation, regional and local schemes for establishing an ecological network areas, settlements and other areas. Land Management uses design of structural elements of the ecological network in the village council, as a rule, begins with ecological and landscape mikrozonationof the village council, held during the preparatory work for the land drafting and finishing the formation of environmentally homogeneous regions, which represents the tied system components of ecological network, environmental measures in the form of local environmental restrictions (encumbrances to use land and other natural resources. Additionally, there are some project organization and territorial measures that increase the sustainability area, such as: key, binders, buffer areas and renewable ecological network. Land management projects on the formation of structural elements of ecological network as territorial restrictions (encumbrances in land are used within the territories Councils determined the location and size of land: - Protection zones around especially valuable natural objects of cultural heritage, meteorological stations, etc. in order to protect them from adverse human impacts; - Protection zones along telecommunication lines, power

  11. Testing the big bang: Light elements, neutrinos, dark matter and large-scale structure

    Energy Technology Data Exchange (ETDEWEB)

    Schramm, D.N. (Chicago Univ., IL (United States) Fermi National Accelerator Lab., Batavia, IL (United States))


    In this series of lectures, several experimental and observational tests of the standard cosmological model are examined. In particular, detailed discussion is presented regarding nucleosynthesis, the light element abundances and neutrino counting; the dark matter problems; and the formation of galaxies and large-scale structure. Comments will also be made on the possible implications of the recent solar neutrino experimental results for cosmology. An appendix briefly discusses the 17 keV thing'' and the cosmological and astrophysical constraints on it. 126 refs., 8 figs., 2 tabs.

  12. Simple model of the Rayleigh-Taylor instability, collapse, and structural elements (United States)

    Goncharov, V. P.; Pavlov, V. I.


    The mechanisms and structural elements of the Rayleigh-Taylor instability whose evolution results in the occurrence of the collapse have been studied in the scope of the rotating shallow water model with horizontal density gradient. Analysis of the instability mechanism shows that two collapse scenarios are possible. One scenario implies anisotropic collapse during which the contact area of a collapsing fragment with the bottom contracts into a spinning segment. The other implies isotropic contracting of the area into a point. The rigorous integral criteria and power laws of collapses are found.

  13. Structural elements of collapses in shallow water flows with horizontally nonuniform density

    Energy Technology Data Exchange (ETDEWEB)

    Goncharov, V. P., E-mail: [Russian Academy of Sciences, Obukhov Institute of Atmospheric Physics (Russian Federation); Pavlov, V. I., E-mail: [Universite de Lille 1, UFR de Mathematiques Pures et Appliquees-LML UMR 8107 (France)


    The mechanisms and structural elements of instability whose evolution results in the occurrence of the collapse are studied in the scope of the rotating shallow water model with a horizontally nonuniform density. The diagram stability based on the integral collapse criterion is suggested to explain system behavior in the space of constants of motion. Analysis of the instability shows that two collapse scenarios are possible. One scenario implies anisotropic collapse during which the contact area of a collapsing drop-like fragment with the bottom contracts into a rotating segment. The other implies isotropic contraction of the area into a point.

  14. Program design by a multidisciplinary team. [for structural finite element analysis on STAR-100 computer (United States)

    Voigt, S.


    The use of software engineering aids in the design of a structural finite-element analysis computer program for the STAR-100 computer is described. Nested functional diagrams to aid in communication among design team members were used, and a standardized specification format to describe modules designed by various members was adopted. This is a report of current work in which use of the functional diagrams provided continuity and helped resolve some of the problems arising in this long-running part-time project.

  15. Random lock-in intervals for tubular structural elements subject to simulated natural wind

    DEFF Research Database (Denmark)

    Christensen, Claus F.; Ditlevsen, Ove Dalager


    The paper reports on wind tunnel experiments with an elastically suspended circular cylinder vibrating under the excitation of natural wind of high turbulence degree. The natural wind turbulence was simulated bysuperposing the low frequency part of the natural wind turbulence on the background high...... structural elements subject to thenatural wind. The engineering relevance of the investigation is supported by comparing with the unrealistic highlyconservative rules of wind induced fatique commonly given in codes of practice. The stochastic lock-in model aswell as the related fatigue calculation procedure...

  16. Numerical study of viscoelastic polymer flow in simplified pore structures using stabilised finite element model

    Energy Technology Data Exchange (ETDEWEB)

    Qi, M.; Wegner, J.; Ganzer, L. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). ITE


    Polymer flooding, as an EOR method, has become one of the most important driving forces after water flooding. The conventional believe is that polymer flooding can only improve sweep efficiency, but it has no contribution to residual oil saturation reduction. However, experimental studies indicated that polymer solution can also improve displacement efficiency and decrease residual oil saturation. To get a better understanding of the mechanism to increase the microscopic sweep efficiency and the displacement efficiency, theoretical studies are required. In this paper, we studied the viscoelasticity effect of polymer by using a numerical simulator, which is based on Finite Element Analysis. Since it is showed experimentally that the first normal stress difference of viscoelastic polymer solution is higher than the second stress difference, the Oldroyd-B model was selected as the constitutive equation in the simulation. Numerical modelling of Oldroyd-B viscoelastic fluids is notoriously difficult. Standard Galerkin finite element methods are prone to numerical oscillations, and there is no convergence as the elasticity of fluid increases. Therefore, we use a stabilised finite element model. In order to verify our model, we first built up a model with the same geometry and fluid properties as presented in literature and compared the results. Then, with the tested model we simulated the effect of viscoelastic polymer fluid on dead pores in three simplified pore structures, which are contraction structure, expansion structure and expansion-contraction structure. Correspondingly, the streamlines and velocity contours of polymer solution, with different Reynolds numbers (Re) and Weissenberg numbers (We), flowing in these three structures are showed. The simulation results indicate that the viscoelasticity of polymer solution is the main contribution to increase the micro-scale sweep efficiency. With higher elasticity, the velocity of polymer solution is getting bigger at


    DEFF Research Database (Denmark)


    The invention relates to a light-weight load-bearing structure, reinforced by core elements (2) of a strong material constituting one or more compression or tension zones in the structure to be cast, which core (2) is surrounded by or adjacent to a material of less strength compared to the core (2......), where the core (2) is constructed from segments (1) of core elements (2) assembled by means of one or more prestressing elements (4). The invention further relates to a method of casting of light-weight load-bearing structures, reinforced by core elements (2) of a strong material constituting one...... or more compression or tension zones in the structure to be cast, which core (2) is surrounded by or adjacent to a material of less strength compared to the core (2), where the core (2) is constructed from segments (1) of core elements (2) assembled and hold together by means of one or more prestressing...

  18. High-resolution structural and elemental analyses of calcium storage structures synthesized by the noble crayfish Astacus astacus. (United States)

    Luquet, Gilles; Salomé, Murielle; Ziegler, Andreas; Paris, Céline; Percot, Aline; Dauphin, Yannicke


    During premolt, crayfish develop deposits of calcium ions, called gastroliths, in their stomach wall. The stored calcium is used for the calcification of parts of the skeleton regularly renewed for allowing growth. Structural and molecular analyses of gastroliths have been primarily performed on three crayfish species, Orconectes virilis, Procambarus clarkii, and more recently, Cherax quadricarinatus. We have performed high-resolution analyses of gastroliths from the native noble crayfish, Astacus astacus, focusing on the microstructure, the mineralogical and elemental composition and distribution in a comparative perspective. Field emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) observations showed a classical layered microstructure composed of 200-nm diameter granules aligned along fibers. These granules are themselves composed of agglomerated nanogranules of 50nm-mean diameters. Denser regions of bigger fused granules are also present. Micro-Raman spectroscopy show that if A. astacus gastroliths, similarly to the other analyzed gastroliths, are mainly composed of amorphous calcium carbonate (ACC), they are also rich in amorphous calcium phosphate (ACP). The presence of a carotenoid pigment is also observed in A. astacus gastrolith contrary to C. quadricarinatus. Energy-dispersive X-ray spectroscopy (EDX) analyses demonstrate the presence of minor elements such as Mg, Sr, Si and P. The distribution of this last element is particularly heterogeneous. X-ray absorption near edge structure spectroscopy (XANES) reveals an alternation of layers more or less rich in phosphorus evidenced in the mineral phase as well as in the organic matrix in different molecular forms. Putative functions of the different P-comprising molecules are discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Multilevel micro-structuring of glassy carbon for precision glass molding of diffractive optical elements (United States)

    Prater, Karin; Dukwen, Julia; Scharf, Toralf; Herzig, Hans Peter; Plöger, Sven; Hermerschmidt, Andreas


    A consumer market for diffractive optical elements in glass can only be created if high efficient elements are available at affordable prices. In diffractive optics the efficiency and optical properties increases with the number of levels used, but in the same way the costs are multiplied by the number if fabrication steps. Replication of multilevel diffractive optical elements in glass would allow cost efficient fabrication but a suitable mold material is needed. Glassy carbon shows a high mechanical strength, thermal stability and non-sticking adhesion properties, which makes it an excellent candidate as mold material for precision compression molding of low and high glass-transition temperature materials. We introduce an 8 level micro structuring process for glassy carbon molds with standard photolithography and a Ti layer as hard mask for reactive ion etching. The molds were applied to thermal imprinting onto low and high transition temperature glass. Optical performance was tested for the molded samples with different designs for laser beamsplitters. The results show a good agreement to the design specification. Our result allow us to show limitations of our fabrication technique and we discussed the suitability of precision glass molding for cost efficient mass production with a high quality.

  20. Trace element structure of the most widespread plants of genus PulmonariaFNx01

    Directory of Open Access Journals (Sweden)

    Dmitriy Kruglov


    Full Text Available Aim: The aim of this work was a comparative research of trace element structure of various organs of three Pulmonaria species. Materials and Methods: The aerial parts of the most widespread plants of genus Pulmonaria such as Pulmonaria officinalis L., Pulmonaria obscura Dumort. and Pulmonaria mollis Wulf. ex Hornem., which were collected in ending of flowering and were used as the research objects. The amount of trace elements (B, K, P, V, Ca, Co, Cu, Fe, Mg, Mn, Mo, Na, Si, Zn, Ag, Al, Ba, Br, Cr, I, Ni, Se, Sr, and Ti was determined by means of mass spectroscopy with inductively coupled plasma. Results: The data clustering has shown that floral shoots and rosellate leaves possess essentially various trace element status. At the same time, the trace elements′ status of organs of researched plants poorly depends on a taxonomic position of the plant. Thereupon, it is obvious that pharmacological activity is defined by organs of plants from which medicines were made, but not by a species of the used plant. Conclusions: The significant distinction in pharmacological activity of preparations depends on the trace elements′ status of used medicinal vegetative raw materials.

  1. Strontium substituted hydroxyapatites: Synthesis and determination of their structural properties, in vitro and in vivo performance

    Energy Technology Data Exchange (ETDEWEB)

    Kaygili, Omer, E-mail: [Department of Physics, Faculty of Science, Firat University, 23119 Elazig (Turkey); Keser, Serhat [Department of Chemistry, Faculty of Science, Firat University, 23119 Elazig (Turkey); Kom, Mustafa [Department of Surgery, Faculty of Veterinary Medicine, Firat University, 23119 Elazig (Turkey); Eroksuz, Yesari [Department of Pathology, Faculty of Veterinary Medicine, Firat University, 23119 Elazig (Turkey); Dorozhkin, Sergey V. [Kudrinskaja square 1-155, Moscow 123242 (Russian Federation); Ates, Tankut [Department of Physics, Faculty of Science, Firat University, 23119 Elazig (Turkey); Ozercan, Ibrahim H. [Department of Pathology, School of Medicine, Firat University, 23119 Elazig (Turkey); Tatar, Cengiz; Yakuphanoglu, Fahrettin [Department of Physics, Faculty of Science, Firat University, 23119 Elazig (Turkey)


    The objective of this study is to present a detailed report related to the synthesis and characterization of strontium substituted hydroxyapatites. Based on this purpose, hydroxyapatite (HAp) bioceramics with different amounts of strontium (e.g., 0, 0.45, 0.90, 1.35, 1.80 and 2.25 at.%) were prepared using a sol–gel method. The effects of Sr substitution on the structural properties and biocompatibility of the samples were studied by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) techniques, in vitro and in vivo tests. All the samples composed of the nanoparticles ranging from 21 to 27 nm. The presence of Sr at low levels influenced the crystal size, crystallinity degree, lattice parameters and volume of the unit cell of the HAp. Both in vitro conditions and soaking period in simulated body fluid (SBF) significantly affected these properties. Especially, the (Ca + Sr)/P molar ratio gradually decreases with increasing soaking period in SBF. Animal experiments revealed the bone formation and osseointegration for all samples, and as compared with other groups, more reasonable, were observed for the sample with the lowest Sr content. - Highlights: • Sr content affects the structural properties of hydroxyapatite. • Bone formation and osseointegration are observed for all the samples. • In vitro conditions cause a significant change in the (Ca + Sr)/P ratio.

  2. Electronic Structure Calculations for Heavy Elements: Radon (Z=86) and Francium (Z=87) (United States)

    Koufos, Alexander; Papaconstantopoulos, Dimitrios


    Electronic structure calculations allow scientists to predict the properties of solids without the use of physical material. Although the ability to manipulate matter has improved dramatically within the past couple decades, some matter is still hard to study. Modern computers not only let us study this matter, but allow us to do it more quickly and just as accurately. The electronic structure of two rare and mostly unstudied elements, Radon (Z=86) and Francium (Z=87), has been calculated. The augmented plane wave (APW) method with local density approximation (LDA) functional as well as the linearized augmented plane wave (LAPW) method with both LDA and generalized gradient approximation (GGA) functionals were used to perform the calculations. Francium total energy calculations gave the fcc structure slightly below the bcc structure with a minimal energy difference of δE=0.33mRy. The difference found is consistent with other alkali metal total energy calculations which do not verify the bcc structure to be the ground state. Radon was predicted to be an insulator with a gap of 0.931 Ry similar to the other noble gases.

  3. Predicting protein folding pathways at the mesoscopic level based on native interactions between secondary structure elements

    Directory of Open Access Journals (Sweden)

    Sze Sing-Hoi


    Full Text Available Abstract Background Since experimental determination of protein folding pathways remains difficult, computational techniques are often used to simulate protein folding. Most current techniques to predict protein folding pathways are computationally intensive and are suitable only for small proteins. Results By assuming that the native structure of a protein is known and representing each intermediate conformation as a collection of fully folded structures in which each of them contains a set of interacting secondary structure elements, we show that it is possible to significantly reduce the conformation space while still being able to predict the most energetically favorable folding pathway of large proteins with hundreds of residues at the mesoscopic level, including the pig muscle phosphoglycerate kinase with 416 residues. The model is detailed enough to distinguish between different folding pathways of structurally very similar proteins, including the streptococcal protein G and the peptostreptococcal protein L. The model is also able to recognize the differences between the folding pathways of protein G and its two structurally similar variants NuG1 and NuG2, which are even harder to distinguish. We show that this strategy can produce accurate predictions on many other proteins with experimentally determined intermediate folding states. Conclusion Our technique is efficient enough to predict folding pathways for both large and small proteins at the mesoscopic level. Such a strategy is often the only feasible choice for large proteins. A software program implementing this strategy (SSFold is available at

  4. Elements of the Chicxulub Impact Structure as Revealed in SRTM and Surface GPS Topographic Data (United States)

    Kinsland, Gary L.; Sanchez, Gary; Kobrick, Michael; Cardador, Manuel Hurtado


    Pope et al. [1] utilized the elevations from the Petroleos Mexicanos (PEMEX) gravity data files to show that the main component of the surface expression of the Chicxulub Impact Structure is a roughly semi-circular, lowrelief depression about 90 km in diameter. They also identified other topographic features and the elements of the buried impact, which possibly led to the development of these features. These are summarized in Table 1. Kinsland et al. [2] presented a connection between these topographic anomalies, small gravity anomalies and buried structure of the impact. Very recently we have acquired digital topography data from NASA s Shuttle Radar Topography Mission (SRTM). Our subset covers 6 square degrees from 20deg N 91degW to 22deg N 88degW (corner to corner) with a pixel size of about 90m. This area includes all of the identified portion of the crater on land.

  5. Crystal Structure of NFAT Bound to the HIV-1 LTR Tandem κB Enhancer Element

    Energy Technology Data Exchange (ETDEWEB)

    Bates, Darren L.; Barthel, Kristen K.B.; Wu, Yongqing; Kalhor, Reza; Stroud, James C.; Giffin, Michael J.; Chen, Lin (UCLA); (Colorado)


    Here, we have determined the crystal structure of the DNA binding domain of NFAT bound to the HIV-1 long terminal repeat (LTR) tandem {kappa}B enhancer element of 3.05 {angstrom} resolution. NFAT binds as a dimer to the upstream {kappa}B site (Core II), but as a monomer to the 3' end of the downstream {kappa}B site (Core I). The DNA shows a significant bend near the 5' end of Core I, where a lysine residue from NFAT bound to the 3' end of Core II inserts into the minor groove and seems to cause DNA bases to flip out. Consistent with this structural feature, the 5' end of Core I become hypersensitive to dimethylsulfate in the in vivo footprinting upon transcriptional activation of the HIV-1 LTR. Our studies provide a basis for futher investigating the functional mechanism of NFAT in HIV-1 transcription and replication.

  6. Coupled mixed-field laminate theory and finite element for smart piezoelectric composite shell structures (United States)

    Saravanos, Dimitris A.


    Mechanics for the analysis of laminated composite shells with piezoelectric actuators and sensors are presented. A new mixed-field laminate theory for piezoelectric shells is formulated in curvilinear coordinates which combines single-layer assumptions for the displacements and a layerwise representation for the electric potential. The resultant coupled governing equations for curvilinear piezoelectric laminates are described. Structural mechanics are subsequently developed and an 8-node finite-element is formulated for the static and dynamic analysis of adaptive composite structures of general laminations containing piezoelectric layers. Evaluations of the method and comparisons with reported results are presented for laminated piezoelectric-composite plates, a closed cylindrical shell with a continuous piezoceramic layer and a laminated composite semi-circular cantilever shell with discrete cylindrical piezoelectric actuators and/or sensors.

  7. Structural Robust Optimal Design based on Orthogonal Experimental and Parametric Finite Element Analysis

    Directory of Open Access Journals (Sweden)

    He Xindang


    Full Text Available In this paper, based on orthogonal experiment, piccolo tube dynamic optimization was performed to achieve the purposes of reducing the time of sample, identifying the key parameters and optimizing design. Firstly, parameterized finite element model of the piccolo tube was built. After that, the orthogonal experiment under four design variables covering three levels was performed. After 10 times dynamics simulation analysis (9 times simulation for orthogonal experiment and 1 time simulation for optimal design verification experiment, the optimal design of the piccolo tube was quickly determined. The first order natural frequency of the piccolo tube was improved to 1771HZ from initial design 1496.3HZ. The trend and sensitivity between the design variables and structural performance were obtained. The analyze process shows that the proposed method is simple and efficient. It can provide technical reference for piccolo tube optimization design and other complex structures.

  8. Nanohairs and nanotubes: Efficient structural elements for gecko-inspired artificial dry adhesives

    KAUST Repository

    Jeong, Hoon Eui


    An overview of the recent progress in the development of gecko-inspired synthetic dry adhesives is presented, with particular emphasis on two major structural elements of nanohairs and nanotubes. With the advance of nanofabrication techniques, recently developed dry adhesives made of nanohairs and nanotubes show excellent adhesion strength, smart directional adhesion as well as rough surface adaptability by better mimicking gecko foot hairs. After a brief description of the requirements for high-performance artificial dry adhesives, a variety of synthetic adhesives are described based on materials and structural features of the gecko-inspired nanostructures. In addition, current challenges and future directions towards an optimized synthetic dry adhesive are presented. © 2009 Elsevier Ltd. All rights reserved.

  9. A comparison of finite element analysis with in vitro bond strength tests of the bracket-cement-enamel system

    NARCIS (Netherlands)

    Algera, T.J.; Feilzer, A.J.; Prahl-Andersen, B.; Kleverlaan, C.J.


    The aim of this study was to determine the in vitro shear bond strength (SBS) and tensile bond strength (TBS) of 45 metal brackets bonded with Transbond XT to bovine enamel. The SBS was determined by loading the short and the long sides of the bracket base. Testing took place after storage of the

  10. Characterization of Aircraft Structural Damage Using Guided Wave Based Finite Element Analysis for In-Flight Structural Health Management (United States)

    Seshadri, Banavara R.; Krishnamurthy, Thiagarajan; Ross, Richard W.


    The development of multidisciplinary Integrated Vehicle Health Management (IVHM) tools will enable accurate detection, diagnosis and prognosis of damage under normal and adverse conditions during flight. The adverse conditions include loss of control caused by environmental factors, actuator and sensor faults or failures, and structural damage conditions. A major concern is the growth of undetected damage/cracks due to fatigue and low velocity foreign object impact that can reach a critical size during flight, resulting in loss of control of the aircraft. To avoid unstable catastrophic propagation of damage during a flight, load levels must be maintained that are below the load-carrying capacity for damaged aircraft structures. Hence, a capability is needed for accurate real-time predictions of safe load carrying capacity for aircraft structures with complex damage configurations. In the present work, a procedure is developed that uses guided wave responses to interrogate damage. As the guided wave interacts with damage, the signal attenuates in some directions and reflects in others. This results in a difference in signal magnitude as well as phase shifts between signal responses for damaged and undamaged structures. Accurate estimation of damage size and location is made by evaluating the cumulative signal responses at various pre-selected sensor locations using a genetic algorithm (GA) based optimization procedure. The damage size and location is obtained by minimizing the difference between the reference responses and the responses obtained by wave propagation finite element analysis of different representative cracks, geometries and sizes.

  11. Two-Element PIFA Array Structure for Polarization Diversity in UMTS Mobile Phones

    Directory of Open Access Journals (Sweden)

    P. Hamouz


    Full Text Available In this paper, we demonstrate the possibility to strongly modify the radiated fields of a UMTS handset by using a phased two-element PIFA array. The structure is composed of a 100x40 mm2 metallic ground plane acting as the Printed Circuit Board (PCB of the mobile phone. Two UMTS PIFAs are located at the top edge of this PCB. They are fed by a double Quasi-Lumped Coupler able to provide a 360 phase difference between its two outputs. By properly choosing the DC bias of the double QuasiLumped Coupler, we can set a specific phase difference between the two PIFAs. In this way the two-element array is able to radiate different electromagnetic fields. Simulated and measured radiation patterns in the two main planes of the chassis are presented for different phase differences. It is especially revealed that the novel twoantenna structure is able to radiate vertically-polarized electric fields in the azimuthal plane of the phone and horizontally-polarized electric fields in the same plane when changing the phase shift between the antennas from 0 to 180. Potential applications are polarization-diversity techniques and Specific Absorption Rate reduction for handsets.

  12. A Highly Flexible, Automated System Providing Reliable Sample Preparation in Element- and Structure-Specific Measurements. (United States)

    Vorberg, Ellen; Fleischer, Heidi; Junginger, Steffen; Liu, Hui; Stoll, Norbert; Thurow, Kerstin


    Life science areas require specific sample pretreatment to increase the concentration of the analytes and/or to convert the analytes into an appropriate form for the detection and separation systems. Various workstations are commercially available, allowing for automated biological sample pretreatment. Nevertheless, due to the required temperature, pressure, and volume conditions in typical element and structure-specific measurements, automated platforms are not suitable for analytical processes. Thus, the purpose of the presented investigation was the design, realization, and evaluation of an automated system ensuring high-precision sample preparation for a variety of analytical measurements. The developed system has to enable system adaption and high performance flexibility. Furthermore, the system has to be capable of dealing with the wide range of required vessels simultaneously, allowing for less cost and time-consuming process steps. However, the system's functionality has been confirmed in various validation sequences. Using element-specific measurements, the automated system was up to 25% more precise compared to the manual procedure and as precise as the manual procedure using structure-specific measurements. © 2015 Society for Laboratory Automation and Screening.

  13. Blood lead: Its effect on trace element levels and iron structure in hemoglobin

    Energy Technology Data Exchange (ETDEWEB)

    Jin, C. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Li, Y. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China)], E-mail:; Li, Y.L. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Zou, Y. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Zhang, G.L. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Normura, M. [Photon Factory, Institute of Materials Structure Science, KEK, Oho, Tsukuba 305 (Japan); Zhu, G.Y. [Institute of Radiation Medicine, Fudan University, Shanghai 200032 (China)


    Lead is a ubiquitous environmental pollutant that induce a broad range of physiological and biochemical dysfunctions. The purpose of this study was to investigate its effects on trace elements and the iron structure in hemoglobin. Blood samples were collected from rats that had been exposed to lead. The concentration of trace elements in whole blood and blood plasma was determined by ICP-MS and the results indicate that lead exists mainly in the red blood cells and only about 1-3% in the blood plasma. Following lead exposure, the concentrations of zinc and iron in blood decrease, as does the hemoglobin level. This indicates that the heme biosynthetic pathway is inhibited by lead toxicity and that lead poisoning-associated anemia occurs. The selenium concentration also decreases after lead exposure, which may lead to an increased rate of free radical production. The effect of lead in the blood on iron structure in hemoglobin was determined by EXAFS. After lead exposure, the Fe-O bond length increases by about 0.07 A and the Fe-Np bond length slightly increases, but the Fe-N{sub {epsilon}} bond length remains unchanged. This indicates that the blood content of Hb increases, but that the content of HbO{sub 2} decreases.

  14. HIV Rev Assembly on the Rev Response Element (RRE: A Structural Perspective

    Directory of Open Access Journals (Sweden)

    Jason W. Rausch


    Full Text Available HIV-1 Rev is an ~13 kD accessory protein expressed during the early stage of virus replication. After translation, Rev enters the nucleus and binds the Rev response element (RRE, a ~350 nucleotide, highly structured element embedded in the env gene in unspliced and singly spliced viral RNA transcripts. Rev-RNA assemblies subsequently recruit Crm1 and other cellular proteins to form larger complexes that are exported from the nucleus. Once in the cytoplasm, the complexes dissociate and unspliced and singly-spliced viral RNAs are packaged into nascent virions or translated into viral structural proteins and enzymes, respectively. Rev binding to the RRE is a complex process, as multiple copies of the protein assemble on the RNA in a coordinated fashion via a series of Rev-Rev and Rev-RNA interactions. Our understanding of the nature of these interactions has been greatly advanced by recent studies using X-ray crystallography, small angle X-ray scattering (SAXS and single particle electron microscopy as well as biochemical and genetic methodologies. These advances are discussed in detail in this review, along with perspectives on development of antiviral therapies targeting the HIV-1 RRE.

  15. Finite Element Analysis of Soft-lined Mandibular Complete Denture and its Supporting Structures

    Directory of Open Access Journals (Sweden)

    Katayoun Sadr


    Full Text Available Background and aims. There are many edentulous people with severely resorbed residual ridges and non-resilient lining mucosa that are unable to tolerate occlusal forces during functional and parafunctional movements. Lining the tissue surface of dentures with a flexible material can theoretically distribute and absorb forces with cushioning effect. The aim of this study was to evaluate the effect of a soft liner on stress levels in mandibular complete denture and its supporting structures by finite element analysis. Materials and methods. A simplified 3-dimensional finite element model of relatively resorbed mandible, mucosa, denture and a soft liner was prepared. Then the model, with and without soft liner, underwent normal vertical and lateral occlusal forces. The stresses were analyzed using the ANSYS 12 software. Results. Using the soft liner increased stress levels up to 18.5% and 30% in the cortical bone and mucosa, respectively, after vertical load was applied in the incisor region. Application of bilateral vertical load on the molar area increased stress in cortical bone u to 44% and in the mucosa up to 29%. Unilateral loading in the canine area increased stress level in the mucosa up to 63.5%. The highest stress was seen at denture base followed by the cortical bone. Conclusion. Use of soft liners increased stress in denture supporting structures. Higher level of stress concentration was observed primarily in the denture base followed by the cortical bone.

  16. Blood lead: Its effect on trace element levels and iron structure in hemoglobin (United States)

    Jin, C.; Li, Y.; Li, Y. L.; Zou, Y.; Zhang, G. L.; Normura, M.; Zhu, G. Y.


    Lead is a ubiquitous environmental pollutant that induce a broad range of physiological and biochemical dysfunctions. The purpose of this study was to investigate its effects on trace elements and the iron structure in hemoglobin. Blood samples were collected from rats that had been exposed to lead. The concentration of trace elements in whole blood and blood plasma was determined by ICP-MS and the results indicate that lead exists mainly in the red blood cells and only about 1-3% in the blood plasma. Following lead exposure, the concentrations of zinc and iron in blood decrease, as does the hemoglobin level. This indicates that the heme biosynthetic pathway is inhibited by lead toxicity and that lead poisoning-associated anemia occurs. The selenium concentration also decreases after lead exposure, which may lead to an increased rate of free radical production. The effect of lead in the blood on iron structure in hemoglobin was determined by EXAFS. After lead exposure, the Fe-O bond length increases by about 0.07 Å and the Fe-Np bond length slightly increases, but the Fe-N ɛ bond length remains unchanged. This indicates that the blood content of Hb increases, but that the content of HbO 2 decreases.

  17. In vivo and in vitro study of the 9{sup 9mT}c-DMSA radiopharmaceutical connection to blood elements; Estudo in vivo e in vitro da ligacao do radiofarmaco 99mTc-DMSA aos elementos sanquineos

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, Rosimeire de S. [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Inst. de Biologia. Dept. de Biofisica e Biometria]|[Hospital Universitario Clementino Fraga Filho, Rio de Janeiro (Brazil); Gomes, Maria L.; Mattos, Deise M.M.; Moreno, Silvana R.F.; Dire, Glaucio F.; Lima, Elaine A.; Lima-Filho, Guilherme L.; Aleixo, Luiz Claudio [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Inst. de Biologia. Dept. de Biofisica e Biometria; Bernardo-Filho, Mario [Universidade do Estado, Rio de Janeiro, RJ (Brazil). Inst. de Biologia. Dept. de Biofisica e Biometria]|[Instituto Nacional do Cancer, Rio de Janeiro (Brazil). Centro de Pesquisa Basica] E-mail:


    Radiopharmaceuticals are widely used in nuclear medicine. The comprehension of their uptake mechanism in target organs, as well as their clearance may depend on the elucidation of their biochemical characteristics, for instance, their binding to blood elements. The reported precipitating studies of blood with radiopharmaceuticals have shown that the results can not be easily compared. Then, we decide evaluate of the binding proteins on the blood elements using trichloroacetic acid (TCA) to determine the radioactivity of the dimercaptosuccinic acid with technetium-99m (99mTc-DMSA) present in precipitating plasma (P) and blood cells (BC). Depending on the TCA concentration we have determined different values in the insoluble fractions of the plasma when the in vivo and in vitro evaluations were carried out. (author)

  18. Analysis on the geometrical shape of T-honeycomb structure by finite element method (FEM) (United States)

    Zain, Fitri; Rosli, Muhamad Farizuan; Effendi, M. S. M.; Abdullah, Mohamad Hariri


    Geometric in design is much related with our life. Each of the geometrical structure interacts with each other. The overall shape of an object contains other shape inside, and there shapes create a relationship between each other in space. Besides that, how geometry relates to the function of the object have to be considerate. In this project, the main purpose was to design the geometrical shape of modular furniture with the shrinking of Polyethylene Terephthalate (PET) jointing system that has good strength when applied load on it. But, the goal of this paper is focusing on the analysis of Static Cases by FEM of the hexagonal structure to obtain the strength when load apply on it. The review from the existing product has many information and very helpful to finish this paper. This project focuses on hexagonal shape that distributed to become a shelf inspired by honeycomb structure. It is very natural look and simple in shape and its modular structure more easily to separate and combine. The method discusses on chapter methodology are the method used to analysis the strength when the load applied to the structure. The software used to analysis the structure is Finite Element Method from CATIA V5R21 software. Bending test is done on the jointing part between the edges of the hexagonal shape by using Universal Tensile Machine (UTM). The data obtained have been calculate by bending test formulae and sketch the graph between flexural strains versus flexural stress. The material selection of the furniture is focused on wood. There are three different types of wood such as balsa, pine and oak, while the properties of jointing also be mentioned in this thesis. Hence, the design structural for honeycomb shape already have in the market but this design has main objective which has a good strength that can withstand maximum load and offers more potentials in the form of furniture.

  19. Wakefield Simulation of CLIC PETS Structure Using Parallel 3D Finite Element Time-Domain Solver T3P

    Energy Technology Data Exchange (ETDEWEB)

    Candel, A.; Kabel, A.; Lee, L.; Li, Z.; Ng, C.; Schussman, G.; Ko, K.; /SLAC; Syratchev, I.; /CERN


    In recent years, SLAC's Advanced Computations Department (ACD) has developed the parallel 3D Finite Element electromagnetic time-domain code T3P. Higher-order Finite Element methods on conformal unstructured meshes and massively parallel processing allow unprecedented simulation accuracy for wakefield computations and simulations of transient effects in realistic accelerator structures. Applications include simulation of wakefield damping in the Compact Linear Collider (CLIC) power extraction and transfer structure (PETS).

  20. Continuous/discontinuous finite element modelling of Kirchhoff plate structures in R^3 using tangential differential calculus (United States)

    Hansbo, Peter; Larson, Mats G.


    We employ surface differential calculus to derive models for Kirchhoff plates including in-plane membrane deformations. We also extend our formulation to structures of plates. For solving the resulting set of partial differential equations, we employ a finite element method based on elements that are continuous for the displacements and discontinuous for the rotations, using C^0-elements for the discretisation of the plate as well as for the membrane deformations. Key to the formulation of the method is a convenient definition of jumps and averages of forms that are d-linear in terms of the element edge normals.

  1. A comparative study of pH modulation and trace elements of various fruit juices on enamel erosion: An in vitro study

    Directory of Open Access Journals (Sweden)

    S.V.S.G Nirmala


    Full Text Available Fruit juices are popular worldwide with children of all ages as they are sweet and perceived to be healthful. This in vitro study was sought to measure pH of 10 different fruit juices, to find out possible erosive effects on human dental enamel of 40 extracted sound premolars and also to measure fluoride and trace elements of these juices. The estimation of pH of fruit juices was done by using Systronic upH 362 pH meter. The erosive effects of fruit juices were tested by using polarized light microscope. Orion electrode was used to measure fluoride. The trace elements were estimated by using Atomic Absorption Spectrophotometer No. 6501F. The pH values in different juices were observed at different levels, and pH values of these juices were more acidic than baseline after 24 hours. As the time increased, the erosion effect became more in pineapple; grape and sugarcane juices, and they had more cariogenic trace elements like selenium, iron and manganese. So, these juices were found to be cariogenic. To conclude, orange, mousambi, mango, pomegranate, apple, chikku and watermelon juices had no erosive effect on the human enamel, with the presence of highest amount of trace elements like fluoride and phosphorous which are considered as strongly cariostatic.

  2. Stiffness degradation-based damage model for RC members and structures using fiber-beam elements (United States)

    Guo, Zongming; Zhang, Yaoting; Lu, Jiezhi; Fan, Jian


    To meet the demand for an accurate and highly efficient damage model with a distinct physical meaning for performance-based earthquake engineering applications, a stiffness degradation-based damage model for reinforced concrete (RC) members and structures was developed using fiber beam-column elements. In this model, damage indices for concrete and steel fibers were defined by the degradation of the initial reloading modulus and the low-cycle fatigue law. Then, section, member, story and structure damage was evaluated by the degradation of the sectional bending stiffness, rod-end bending stiffness, story lateral stiffness and structure lateral stiffness, respectively. The damage model was realized in Matlab by reading in the outputs of OpenSees. The application of the damage model to RC columns and a RC frame indicates that the damage model is capable of accurately predicting the magnitude, position, and evolutionary process of damage, and estimating story damage more precisely than inter-story drift. Additionally, the damage model establishes a close connection between damage indices at various levels without introducing weighting coefficients or force-displacement relationships. The development of the model has perfected the damage assessment function of OpenSees, laying a solid foundation for damage estimation at various levels of a large-scale structure subjected to seismic loading.

  3. Approach to Operational Experimental Estimation of Static Stresses of Elements of Mechanical Structures (United States)

    Sedov, A. V.; Kalinchuk, V. V.; Bocharova, O. V.


    The evaluation of static stresses and strength of units and components is a crucial task for increasing reliability in the operation of vehicles and equipment, to prevent emergencies, especially in structures made of metal and composite materials. At the stage of creation and commissioning of structures to control the quality of manufacturing of individual elements and components, diagnostic control methods are widely used. They are acoustic, ultrasonic, X-ray, radiation methods and others. The using of these methods to control the residual life and the degree of static stresses of units and parts during operation is fraught with great difficulties both in methodology and in instrumentation. In this paper, the authors propose an effective approach of operative control of the degree of static stresses of units and parts of mechanical structures which are in working condition, based on recording the changing in the surface wave properties of a system consisting of a sensor and a controlled environment (unit, part). The proposed approach of low-frequency diagnostics of static stresses presupposes a new adaptive-spectral analysis of a surface wave created by external action (impact). It is possible to estimate implicit stresses of structures in the experiment due to this approach.

  4. Structure-aided prediction of mammalian transcription factor complexes in conserved non-coding elements

    KAUST Repository

    Guturu, H.


    Mapping the DNA-binding preferences of transcription factor (TF) complexes is critical for deciphering the functions of cis-regulatory elements. Here, we developed a computational method that compares co-occurring motif spacings in conserved versus unconserved regions of the human genome to detect evolutionarily constrained binding sites of rigid TF complexes. Structural data were used to estimate TF complex physical plausibility, explore overlapping motif arrangements seldom tackled by non-structure-aware methods, and generate and analyse three-dimensional models of the predicted complexes bound to DNA. Using this approach, we predicted 422 physically realistic TF complex motifs at 18% false discovery rate, the majority of which (326, 77%) contain some sequence overlap between binding sites. The set of mostly novel complexes is enriched in known composite motifs, predictive of binding site configurations in TF-TF-DNA crystal structures, and supported by ChIP-seq datasets. Structural modelling revealed three cooperativity mechanisms: direct protein-protein interactions, potentially indirect interactions and \\'through-DNA\\' interactions. Indeed, 38% of the predicted complexes were found to contain four or more bases in which TF pairs appear to synergize through overlapping binding to the same DNA base pairs in opposite grooves or strands. Our TF complex and associated binding site predictions are available as a web resource at

  5. Nuclear Structure of the Heaviest Elements – Investigated at SHIP-GSI

    Directory of Open Access Journals (Sweden)

    Heßberger Fritz Peter


    Full Text Available The quest for the heaviest nuclei that can exist is a basic topic in natural science as their stability is characterized by a delicate interplay of short range nuclear forces acting between the nucleons (protons and neutrons and long-range Coulomb forces acting solely between charged particles, i.e. the protons. As the stability of a nucleus is strongly correlated to its structure, understanding the nuclear structure of heaviest nuclei is presently a main challenge of experimental and theoretical investigations concerning the field of Superheavy Elements. At the velocity filter SHIP at GSI Darmstadt an extensive program on nuclear structure investigations has been started about a decade ago. The project covered both as well systematic investigations of single particle levels in odd-mass isotopes populated by α-decay as investigation of two- or fourquasi-particle states forming K isomers and was supplemented by direct mass measurements at SHIPTRAP and investigation of spontaneous fission properties. Recent experimental studies allowed to extend the systematics of low lying levels in N = 151 and N = 153 up to 255Rf and 259Sg, investigation of possible relations between nuclear structure and fission properties of odd-mass nuclei and investigation of shell strengths at N = 152 and towards N = 162.

  6. Application of the wave finite element method to reinforced concrete structures with damage (United States)

    El Masri, Evelyne; Ferguson, Neil; Waters, Timothy


    Vibration based methods are commonly deployed to detect structural damage using sensors placed remotely from potential damage sites. Whilst many such techniques are modal based there are advantages to adopting a wave approach, in which case it is essential to characterise wave propagation in the structure. The Wave Finite Element method (WFE) is an efficient approach to predicting the response of a composite waveguide using a conventional FE model of a just a short segment. The method has previously been applied to different structures such as laminated plates, thinwalled structures and fluid-filled pipes. In this paper, the WFE method is applied to a steel reinforced concrete beam. Dispersion curves and wave mode shapes are first presented from free wave solutions, and these are found to be insensitive to loss of thickness in a single reinforcing bar. A reinforced beam with localised damage is then considered by coupling an FE model of a short damaged segment into the WFE model of the undamaged beam. The fundamental bending, torsion and axial waves are unaffected by the damage but some higher order waves of the cross section are significantly reflected close to their cut-on frequencies. The potential of this approach for detecting corrosion and delamination in reinforced concrete beams will be investigated in future work.

  7. Incubation under fluid dynamic conditions markedly improves the structural preservation in vitro of explanted skeletal muscles. (United States)

    Carton, Flavia; Calderan, Laura; Malatesta, Manuela


    Explanted organs and tissues represent suitable experimental systems mimicking the functional and structural complexity of the living organism, with positive ethical and economic impact on research activities. However, their preservation in culture is generally limited, thus hindering their application as experimental models for biomedical research. In the present study, we investigated the potential of an innovative fluid dynamic culture system to improve the structural preservation in vitro of explanted mouse skeletal muscles (soleus). We used light and transmission electron microscopy to compare the morphological features of muscles maintained either in multiwell plates under conventional conditions or in a bioreactor mimicking the flow of physiological fluids. Our results demonstrate that fluid dynamic conditions markedly slowed the progressive structural deterioration of the muscle tissue occurring during the permanence in the culture medium, prolonging the preservation of some organelles such as mitochondria up to 48 h.

  8. Coupled agent-based and finite-element models for predicting scar structure following myocardial infarction. (United States)

    Rouillard, Andrew D; Holmes, Jeffrey W


    Following myocardial infarction, damaged muscle is gradually replaced by collagenous scar tissue. The structural and mechanical properties of the scar are critical determinants of heart function, as well as the risk of serious post-infarction complications such as infarct rupture, infarct expansion, and progression to dilated heart failure. A number of therapeutic approaches currently under development aim to alter infarct mechanics in order to reduce complications, such as implantation of mechanical restraint devices, polymer injection, and peri-infarct pacing. Because mechanical stimuli regulate scar remodeling, the long-term consequences of therapies that alter infarct mechanics must be carefully considered. Computational models have the potential to greatly improve our ability to understand and predict how such therapies alter heart structure, mechanics, and function over time. Toward this end, we developed a straightforward method for coupling an agent-based model of scar formation to a finite-element model of tissue mechanics, creating a multi-scale model that captures the dynamic interplay between mechanical loading, scar deformation, and scar material properties. The agent-based component of the coupled model predicts how fibroblasts integrate local chemical, structural, and mechanical cues as they deposit and remodel collagen, while the finite-element component predicts local mechanics at any time point given the current collagen fiber structure and applied loads. We used the coupled model to explore the balance between increasing stiffness due to collagen deposition and increasing wall stress due to infarct thinning and left ventricular dilation during the normal time course of healing in myocardial infarcts, as well as the negative feedback between strain anisotropy and the structural anisotropy it promotes in healing scar. The coupled model reproduced the observed evolution of both collagen fiber structure and regional deformation following coronary

  9. Topoisomerase IB of Deinococcus radiodurans resolves guanine quadruplex DNA structures in vitro. (United States)

    Kota, Swathi; Misra, Hari S


    Deinococcus radiodurans genome contains a large number of guanine repeats interrupted by a few non-guanine bases, termed G motifs. Some of these G motifs were shown forming guanine quadruplex (G4) DNA structure in vitro. How is the formation and relaxation of G4 DNA regulated in the genome of D. radiodurans is not known and is worth investigating. Here, we showed that the topoisomerase Ib of D. radiodurans (DraTopoIB) could change the electrophoretic mobility of fast migrating intramolecular recF-G4 DNA into the slow migrating species. DraTopoIB also reduced the positive ellipticity in circular diachroism (CD) spectra of intramolecular recF-G4 DNA structures stabilized by K+. On the contrary, when DraTopoIB is incubated with G-motifs annealed without K+, it showed neither any change in electrophoretic mobility nor was ellipticity of the CD spectra affected. DNA synthesis by Taq DNA polymerase through G4 DNA structure was attenuated in the presence of G4 DNA binding drugs, which was abrogated by DraTopoIB. This implies that DraTopoIB could destabilize the G4 DNA structure, which is required for G4 drugs binding and stabilization. Camptothecin treatment inhibited DraTopoIB activity on intramolecular G4 DNA structures. These results suggested that DraTopoIB can relax intramolecular G4 DNA structure in vitro and it may be one such protein that could resolve G4 DNA under normal growth conditions in D. radiodurans.

  10. Heterogeneous structure and surface tension effects on mechanical response in pulmonary acinus: A finite element analysis. (United States)

    Koshiyama, Kenichiro; Nishimoto, Keisuke; Ii, Satoshi; Sera, Toshihiro; Wada, Shigeo


    The pulmonary acinus is a dead-end microstructure that consists of ducts and alveoli. High-resolution micro-CT imaging has recently provided detailed anatomical information of a complete in vivo acinus, but relating its mechanical response with its detailed acinar structure remains challenging. This study aimed to investigate the mechanical response of acinar tissue in a whole acinus for static inflation using computational approaches. We performed finite element analysis of a whole acinus for static inflation. The acinar structure model was generated based on micro-CT images of an intact acinus. A continuum mechanics model of the lung parenchyma was used for acinar tissue material model, and surface tension effects were explicitly included. An anisotropic mechanical field analysis based on a stretch tensor was combined with a curvature-based local structure analysis. The airspace of the acinus exhibited nonspherical deformation as a result of the anisotropic deformation of acinar tissue. A strain hotspot occurred at the ridge-shaped region caused by a rod-like deformation of acinar tissue on the ridge. The local structure becomes bowl-shaped for inflation and, without surface tension effects, the surface of the bowl-shaped region primarily experiences isotropic deformation. Surface tension effects suppressed the increase in airspace volume and inner surface area, while facilitating anisotropic deformation on the alveolar surface. In the lungs, the heterogeneous acinar structure and surface tension induce anisotropic deformation at the acinar and alveolar scales. Further research is needed on structural variation of acini, inter-acini connectivity, or dynamic behavior to understand multiscale lung mechanics. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Structural analysis of eyespots: dynamics of morphogenic signals that govern elemental positions in butterfly wings. (United States)

    Otaki, Joji M


    To explain eyespot colour-pattern determination in butterfly wings, the induction model has been discussed based on colour-pattern analyses of various butterfly eyespots. However, a detailed structural analysis of eyespots that can serve as a foundation for future studies is still lacking. In this study, fundamental structural rules related to butterfly eyespots are proposed, and the induction model is elaborated in terms of the possible dynamics of morphogenic signals involved in the development of eyespots and parafocal elements (PFEs) based on colour-pattern analysis of the nymphalid butterfly Junonia almana. In a well-developed eyespot, the inner black core ring is much wider than the outer black ring; this is termed the inside-wide rule. It appears that signals are wider near the focus of the eyespot and become narrower as they expand. Although fundamental signal dynamics are likely to be based on a reaction-diffusion mechanism, they were described well mathematically as a type of simple uniformly decelerated motion in which signals associated with the outer and inner black rings of eyespots and PFEs are released at different time points, durations, intervals, and initial velocities into a two-dimensional field of fundamentally uniform or graded resistance; this produces eyespots and PFEs that are diverse in size and structure. The inside-wide rule, eyespot distortion, structural differences between small and large eyespots, and structural changes in eyespots and PFEs in response to physiological treatments were explained well using mathematical simulations. Natural colour patterns and previous experimental findings that are not easily explained by the conventional gradient model were also explained reasonably well by the formal mathematical simulations performed in this study. In a mode free from speculative molecular interactions, the present study clarifies fundamental structural rules related to butterfly eyespots, delineates a theoretical basis for the

  12. The in vitro evolution of resorbable brushite cements: A physico-chemical, micro-structural and mechanical study. (United States)

    Gallo, Marta; Tadier, Solène; Meille, Sylvain; Gremillard, Laurent; Chevalier, Jérôme


    The mechanisms by which calcium phosphate bone substitutes evolve and are resorbed in vivo are not yet fully known. In particular, the formation of intermediate phases during resorption and evolution of the mechanical properties may be of crucial interest for their clinical efficiency. The in vitro tests proposed here are the first steps toward understanding these phenomena. Microporous Dicalcium Phosphate Dihydrate (DCPD) samples were immersed in tris(hydroxymethyl)aminomethane (TRIS) and Phosphate Buffered Saline (PBS) solutions, with or without daily refresh of the medium, for time-points up to 14days. Before and after immersion, samples were extensively characterised in terms of morphology, chemistry (XRD coupled with Rietveld analysis), microstructure (X-ray tomography, SEM observations) and local mechanical properties (instrumented micro-indentation). The composition of the immersion solutions was monitored in parallel (pH, elemental analysis). The results show the influence and importance of the experimental set-up and protocol on the formation of apatite and octacalcium phosphate concurrently to DCPD dissolution; moreover, strong inter-correlations between physico-chemistry, microstructure and mechanics are demonstrated. Ideally, the resorption kinetics of biodegradable bone substitutes should be controlled to favor the healing processes of bone. Although biodegradable bone grafts are already used in surgeries, their resorption process is still partially unknown. The present work studies these resorption phenomena, their kinetics and mechanisms and their consequences on the properties of a calcium phosphate resorbable material. The original in vitro approach developed in this work couples for the first time physico-chemical, micro-structural and mechanical assessments. The dissolution of the CaP phase in body fluids and the reprecipitation of more stable phases are studied on a local scale, which has permitted to evidence and monitor the development of a

  13. Methylation of vesicular stomatitis virus (VSV) mRNA 5'-cap structures in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Hammond, D.C.; Lesnaw, J.A.


    Monocistronic VSV mRNAs synthesized by subviral particles in vitro display the methylated 5'-cap structure m'G(5')ppp(5')Am. The authors have detected both monomethylated cap structures, m/sup 7/G(5')ppp(5')A and G(5')Am, in reactions containing suboptimal concentrations of AdoMet. To assess the putative precursor roles of these cap structures the authors devised dual label pulse-chase analyses employing S-(CH/sub 3/-/sup 3/H)-AdoMet and (..beta..-/sup 32/P)GTP. The labeled cap structures were analyzed by HPLC. The simultaneous chasing of both radiolabeled substrates allowed 1) the isolation of a specific set of caps labeled as (..beta..-/sup 32/P)-R/sup 7/G(5')ppp(5')AR (R=H or CH/sub 3/) and 2) the determination of the transcriptive fate of each intermediate cap structure within the set. The results demonstrated that both monomethylated cap structures serve as intermediates for the dimethylated cap and that the order of cap methylation is non-compulsory. These data, coupled with previous observations of hypomethylated cap structures in polyadenylated RNAs, have suggested that methylation occurs in a chain length dependent window.

  14. Synthesis, structure and in vitro cytostatic activity of ferrocene-Cinchona hybrids. (United States)

    Kocsis, László; Szabó, Ildikó; Bősze, Szilvia; Jernei, Tamás; Hudecz, Ferenc; Csámpai, Antal


    Exploring copper(I)- and ruthenium(II)-catalyzed azide-alkyne cycloadditions and a Sonogashira protocol, novel cytostatic ferrocene-cinchona hybrids were synthetized displaying significant in vitro activity on HepG-2 and HT-29 cells. Preliminary SAR studies disclosed that compounds incorporating linkers with 1,2,3-triazole and chalchone residues can be considered as promising lead structures. According to the best of our knowledge this is the first letter on the incorporation of ferrocene nucleus in the reputed cinchona family via triazole and chalcone linkers with established pharmaceutical profile. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Storage Conditions of Skin Affect Tissue Structure and Subsequent in vitro Percutaneous Penetration

    DEFF Research Database (Denmark)

    Nielsen, J B; Plasencia, I; Sørensen, J A


    fluorescence microscopy) and in vitro percutaneous penetration of caffeine under four different storage conditions using skin samples from the same donors: fresh skin, skin kept at -20°C for 3 weeks (with or without the use of polyethylene glycol) and at -80°C. Our results show a correlation between increasing...... permeation of caffeine and tissue structural damage caused by the storage conditions, most so after skin storage at -80°C. The presented approach, which combines imaging techniques with studies on percutaneous penetration, enables the link between tissue damage at selected depths and penetration...

  16. Structural and Functional Analysis of the RNA Transport Element, a Member of an Extensive Family Present in the Mouse Genome (United States)

    Smulevitch, Sergey; Michalowski, Daniel; Zolotukhin, Andrei S.; Schneider, Ralf; Bear, Jenifer; Roth, Patricia; Pavlakis, George N.; Felber, Barbara K.


    We previously identified an RNA transport element (RTE), present in a subclass of rodent intracisternal A particle retroelements (F. Nappi, R. Schneider, A. Zolotukhin, S. Smulevitch, D. Michalowski, J. Bear, B. Felber, and G. Pavlakis, J. Virol. 75:4558-4569, 2001), that is able to replace Rev-responsive element regulation in human immunodeficiency virus type 1. RTE-directed mRNA export is mediated by a still-unknown cellular factor(s), is independent of the CRM1 nuclear export receptor, and is conserved among vertebrates. Here we show that this RTE folds into an extended RNA secondary structure and thus does not resemble any known RTEs. Computer searches revealed the presence of 105 identical elements and more than 3,000 related elements which share at least 70% sequence identity with the RTE and which are found on all mouse chromosomes. These related elements are predicted to fold into RTE-like structures. Comparison of the sequences and structures revealed that the RTE and related elements can be divided into four groups. Mutagenesis of the RTE revealed that the minimal element contains four internal stem-loops, which are indispensable for function in mammalian cells. In contrast, only part of the element is essential to mediate RNA transport in microinjected Xenopus laevis oocyte nuclei. Importantly, the minimal RTE able to promote RNA transport has key structural features which are preserved in all the RTE-related elements, further supporting their functional importance. Therefore, RTE function depends on a complex secondary structure that is important for the interaction with the cellular export factor(s). PMID:15681436

  17. Micromechanical modeling of open cell structures with application in finite element analysis of vertebral body mechanics (United States)

    Overaker, David Wolfgang


    A nonlinear micromechanical model for two-dimensional irregular hexagonal foams has been developed that allows for anisotropy in morphology and/or material. Based upon the orientation, cross-section, length, and material properties of each strut, the resulting micro-level beam behavior within the unit cell determines its structural properties. Nonlinearity is introduced as coupled elasto-plastic beam behavior, where the elasto-plastic behavior of each beam is considered. The analytical formulation for the stiffness matrix of the general elasto-plastic unit cell is found by considering compatibility and equilibrium of the unit cell. The structural properties of the elasto-plastic unit cell are embedded in a continuum finite element model as material properties, thus capturing the microstructure of the foam in an accurate and efficient model. Structural nonlinearity is therefore directly linked to localized plasticity and its evolution at the micro-level. Elastic analyses investigated the degree of anisotropy in structural properties that was induced by various morphological changes. Plastic analyses showed how structural nonlinearity could be explained by localized microstructural behavior. The formulation for the three-dimensional regular hexagonal foam was then developed as an extension of the two-dimensional formulation. Sensitivity of the constitutive properties to the microstructure and its orientation was studied. The model was then validated for application as an idealized model of the porous trabecular bone material of the human vertebra. The mechanical behavior of the model was shown to capture the basic characteristics of actual bone, where changes in behavior associated with age-related changes in bone architecture (increasing porosity with age) were also considered. Nonlinearity in the load-displacement behavior of trabecular bone specimens was directly linked to localized microstructural nonlinearity and its evolution. Validation was followed by

  18. Applicability of an in vitro gastrointestinal digestion method to evaluation of toxic elements bioaccessibility from algae for human consumption. (United States)

    Desideri, Donatella; Roselli, Carla; Feduzi, Laura; Ugolini, Lucia; Meli, Maria Assunta


    This study aimed to investigate the bioaccessibility of toxic elements, including aluminum (Al), arsenic (As), nickel (Ni), cadmium (Cd), and lead (Pb) in five commercial algae consumed by humans in Italy. The degree of bioaccessibility of these elements may have important implications for human health. Simulation of gastrointestinal tract (GIT) digestion was divided into three stages through use of synthetic saliva, gastric, and bile-pancreas solutions. After pre-treatment with a saliva solution, seaweed samples underwent one of the following treatments: (1) simulated gastric digestion only or (2) simulated complete GIT digestion (gastric digestion followed by bile-pancreas digestion). The bioaccessibility of these toxic elements ranged from approximately 5% to 73% and from 4% to 77% in gastric and GIT digestion, respectively. The bioaccessibility of Al and Pb is poor (5-15%), As and Ni were fairly (40-55%), while Cd displayed a high bioaccessibility. No significant differences in toxic elements mobility was found between samples that only underwent gastric digestion compared to those that underwent a complete GIT digestion.

  19. Asynchronous Communication: Investigating the Influences of Relational Elements and Background on the Framing Structure of Emails

    Directory of Open Access Journals (Sweden)

    Mohammad Awad AlAfnan


    Full Text Available This study explored the influences of relational elements and the background of communicators on the framing structure of email messages that were exchanged in an educational Institute in Malaysia. The investigation revealed that social distance played a more significant role than power relations as Malaysian respondents are, generally, more polite to distant colleagues than they are to close colleagues regardless of their organizational position. It was also revealed that the ethnic background of email writers prompted the framing structure of the emails as the use of the pre-closing move and ‘thank you’ as a closing marker was generally a Malaysian practice. This study also revealed that the framing structure of the emails depended on the direction of the message as the majority of the emails that were sent to external contacts included an auto signature, whereas the internally exchanged email were mainly signed off using the first name of the sender alone.  In addition, it was revealed that email writers in the educational Institute had a very high tendency to name their messages as almost 100 percent of the emails included the identifying topic move, which was generally clearly or broadly informative move. Keywords: Email communication, Relational factors, Framing moves, Social distance, Power relations

  20. Reelin exerts structural, biochemical and transcriptional regulation over presynaptic and postsynaptic elements in the adult hippocampus

    Directory of Open Access Journals (Sweden)

    Carles eBosch


    Full Text Available Reelin regulates neuronal positioning and synaptogenesis in the developing brain, and adult brain plasticity. Here we used transgenic mice overexpressing Reelin (Reelin-OE mice to perform a comprehensive dissection of the effects of this protein on the structural and biochemical features of dendritic spines and axon terminals in the adult hippocampus. Electron microscopy (EM revealed both higher density of synapses and structural complexity of both pre- and postsynaptic elements in transgenic mice than in WT mice. Dendritic spines had larger spine apparatuses, which correlated with a redistribution of Synaptopodin. Most of the changes observed in Reelin-OE mice were reversible after blockade of transgene expression, thus supporting the specificity of the observed phenotypes. Western blot and transcriptional analyses did not show major changes in the expression of pre- or postsynaptic proteins, including SNARE proteins, glutamate receptors, and scaffolding and signaling proteins. However, EM immunogold assays revealed that the NMDA receptor subunits NR2a and NR2b, and p-Cofilin showed a redistribution from synaptic to extrasynaptic pools. Taken together with previous studies, the present results suggest that Reelin regulates the structural and biochemical properties of adult hippocampal synapses by increasing their density and morphological complexity and by modifying the distribution and trafficking of major glutamatergic components.

  1. Structure and magnetism in novel group IV element-based magnetic materials

    Energy Technology Data Exchange (ETDEWEB)

    Tsui, Frank [Univ. of North Carolina, Chapel Hill, NC (United States)


    The project is to investigate structure, magnetism and spin dependent states of novel group IV element-based magnetic thin films and heterostructures as a function of composition and epitaxial constraints. The materials systems of interest are Si-compatible epitaxial films and heterostructures of Si/Ge-based magnetic ternary alloys grown by non-equilibrium molecular beam epitaxy (MBE) techniques, specifically doped magnetic semiconductors (DMS) and half-metallic Heusler alloys. Systematic structural, chemical, magnetic, and electrical measurements are carried out, using x-ray microbeam techniques, magnetotunneling spectroscopy and microscopy, and magnetotransport. The work is aimed at elucidating the nature and interplay between structure, chemical order, magnetism, and spin-dependent states in these novel materials, at developing materials and techniques to realize and control fully spin polarized states, and at exploring fundamental processes that stabilize the epitaxial magnetic nanostructures and control the electronic and magnetic states in these complex materials. Combinatorial approach provides the means for the systematic studies, and the complex nature of the work necessitates this approach.

  2. The structure of the SOLE element of oskar mRNA. (United States)

    Simon, Bernd; Masiewicz, Pawel; Ephrussi, Anne; Carlomagno, Teresa


    mRNA localization by active transport is a regulated process that requires association of mRNPs with protein motors for transport along either the microtubule or the actin cytoskeleton. oskar mRNA localization at the posterior pole of the Drosophila oocyte requires a specific mRNA sequence, termed the SOLE, which comprises nucleotides of both exon 1 and exon 2 and is assembled upon splicing. The SOLE folds into a stem-loop structure. Both SOLE RNA and the exon junction complex (EJC) are required for oskar mRNA transport along the microtubules by kinesin. The SOLE RNA likely constitutes a recognition element for a yet unknown protein, which either belongs to the EJC or functions as a bridge between the EJC and the mRNA. Here, we determine the solution structure of the SOLE RNA by Nuclear Magnetic Resonance spectroscopy. We show that the SOLE forms a continuous helical structure, including a few noncanonical base pairs, capped by a pentanucleotide loop. The helix displays a widened major groove, which could accommodate a protein partner. In addition, the apical helical segment undergoes complex dynamics, with potential functional significance. © 2015 Simon et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.

  3. Polymorphism in Elemental Silicon: Probabilistic Interpretation of the Realizability of Metastable Structures

    Energy Technology Data Exchange (ETDEWEB)

    Stevanovic, Vladan [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Jones, Eric [National Renewable Energy Laboratory (NREL), Golden, CO (United States)


    With few systems of technological interest having been studied as extensively as elemental silicon, there currently exists a wide disparity between the number of predicted low-energy silicon polymorphs and those that have been experimentally realized as metastable at ambient conditions. We put forward an explanation for this disparity wherein the likelihood of formation of a given polymorph under near-equilibrium conditions can be estimated on the basis of mean-field isothermal-isobaric (N,p,T) ensemble statistics. The probability that a polymorph will be experimentally realized is shown to depend upon both the hypervolume of that structure's potential energy basin of attraction and a Boltzmann factor weight containing the polymorph's potential enthalpy per particle. Both attributes are calculated using density functional theory relaxations of randomly generated initial structures. We find that the metastable polymorphism displayed by silicon can be accounted for using this framework to the exclusion of a very large number of other low-energy structures.

  4. Structural evaluation of a nickel base super alloy metal foam via NDE and finite element (United States)

    Abdul-Aziz, Ali; Abumeri, G.; Garg, Mohit; Young, P. G.


    Cellular materials are known to be useful in the application of designing light but stiff structures. This applies to various components used in various industries such as rotorcraft blades, car bodies or portable electronic devices. Structural application of the metal foam is typically confined to light weight sandwich panels, made up of thin solid face sheets and a metallic foam core. The resulting high-stiffness structure is lighter than that constructed only out of the solid metal material. The face sheets carry the applied in-plane and bending loads and the role of the foam core is separate the face sheets to carry some of the shear stresses, while remaining integral with the face sheet. Many challenges relating to the fabrication and testing of these metal foam panels continue to exist due to some mechanical properties falling short of their theoretical potential. Hence in this study, a detailed three dimensional foam structure is generated using series of 2D Computer Tomography (CT) scans, on Haynes 25 metal foam. Series of the 2D images are utilized to construct a high precision solid model including all the fine details within the metal foam as detected by the CT scanning technique. Subsequently, a finite element analysis is then performed on an as fabricated metal foam microstructures to evaluate the foam structural durability and behavior under tensile and compressive loading conditions. The analysis includes a progressive failure analysis (PFA) using GENOA code to further assess the damage initiation, propagation, and failure. The open cell metal foam material is a cobalt-nickel-chromium-tungsten alloy that combines excellent high-temperature strength with good resistance to oxidizing environments up to 1800 °F (980 °C) for prolonged exposures. The foam is formed by a powder metallurgy process with an approximate 100 pores per inch (PPI).

  5. Nonlinear Finite Element Analysis of a Composite Non-Cylindrical Pressurized Aircraft Fuselage Structure (United States)

    Przekop, Adam; Wu, Hsi-Yung T.; Shaw, Peter


    The Environmentally Responsible Aviation Project aims to develop aircraft technologies enabling significant fuel burn and community noise reductions. Small incremental changes to the conventional metallic alloy-based 'tube and wing' configuration are not sufficient to achieve the desired metrics. One of the airframe concepts that might dramatically improve aircraft performance is a composite-based hybrid wing body configuration. Such a concept, however, presents inherent challenges stemming from, among other factors, the necessity to transfer wing loads through the entire center fuselage section which accommodates a pressurized cabin confined by flat or nearly flat panels. This paper discusses a nonlinear finite element analysis of a large-scale test article being developed to demonstrate that the Pultruded Rod Stitched Efficient Unitized Structure concept can meet these challenging demands of the next generation airframes. There are specific reasons why geometrically nonlinear analysis may be warranted for the hybrid wing body flat panel structure. In general, for sufficiently high internal pressure and/or mechanical loading, energy related to the in-plane strain may become significant relative to the bending strain energy, particularly in thin-walled areas such as the minimum gage skin extensively used in the structure under analysis. To account for this effect, a geometrically nonlinear strain-displacement relationship is needed to properly couple large out-of-plane and in-plane deformations. Depending on the loading, this nonlinear coupling mechanism manifests itself in a distinct manner in compression- and tension-dominated sections of the structure. Under significant compression, nonlinear analysis is needed to accurately predict loss of stability and postbuckled deformation. Under significant tension, the nonlinear effects account for suppression of the out-of-plane deformation due to in-plane stretching. By comparing the present results with the previously

  6. Precise colocalization of interacting structural and pigmentary elements generates extensive color pattern variation in Phelsuma lizards. (United States)

    Saenko, Suzanne V; Teyssier, Jérémie; van der Marel, Dirk; Milinkovitch, Michel C


    Color traits in animals play crucial roles in thermoregulation, photoprotection, camouflage, and visual communication, and are amenable to objective quantification and modeling. However, the extensive variation in non-melanic pigments and structural colors in squamate reptiles has been largely disregarded. Here, we used an integrated approach to investigate the morphological basis and physical mechanisms generating variation in color traits in tropical day geckos of the genus Phelsuma. Combining histology, optics, mass spectrometry, and UV and Raman spectroscopy, we found that the extensive variation in color patterns within and among Phelsuma species is generated by complex interactions between, on the one hand, chromatophores containing yellow/red pteridine pigments and, on the other hand, iridophores producing structural color by constructive interference of light with guanine nanocrystals. More specifically, we show that 1) the hue of the vivid dorsolateral skin is modulated both by variation in geometry of structural, highly ordered narrowband reflectors, and by the presence of yellow pigments, and 2) that the reflectivity of the white belly and of dorsolateral pigmentary red marks, is increased by underlying structural disorganized broadband reflectors. Most importantly, these interactions require precise colocalization of yellow and red chromatophores with different types of iridophores, characterized by ordered and disordered nanocrystals, respectively. We validated these results through numerical simulations combining pigmentary components with a multilayer interferential optical model. Finally, we show that melanophores form dark lateral patterns but do not significantly contribute to variation in blue/green or red coloration, and that changes in the pH or redox state of pigments provide yet another source of color variation in squamates. Precisely colocalized interacting pigmentary and structural elements generate extensive variation in lizard color

  7. ED-XRF spectrometric analysis of comparative elemental composition of in vivo and in vitro roots of Andrographis paniculata (Burm.f.) Wall. ex Nees-a multi-medicinal herb

    Energy Technology Data Exchange (ETDEWEB)

    Behera, P.R., E-mail: [Plant Cell and Tissue culture Facility, Post-Graduate Department of Botany, Utkal University, Vani Vihar, Bhubaneswar 751004, Orissa (India); Plant Biotechnology Lab, Institute of Minerals and Materials Technology (CSIR), Bhubaneswar 751013, Orissa (India); Nayak, P., E-mail: [Plant Cell and Tissue culture Facility, Post-Graduate Department of Botany, Utkal University, Vani Vihar, Bhubaneswar 751004, Orissa (India); Plant Biotechnology Lab, Institute of Minerals and Materials Technology (CSIR), Bhubaneswar 751013, Orissa (India); Barik, D.P., E-mail: [Plant Cell and Tissue culture Facility, Post-Graduate Department of Botany, Utkal University, Vani Vihar, Bhubaneswar 751004, Orissa (India); Rautray, T.R., E-mail: [Ion Beam Laboratory, Institute of Physics, Bhubaneswar 751013, Orissa (India); Thirunavoukkarasu, M., E-mail: [Plant Biotechnology Lab, Institute of Minerals and Materials Technology (CSIR), Bhubaneswar 751013, Orissa (India); Chand, P.K., E-mail: [Plant Cell and Tissue culture Facility, Post-Graduate Department of Botany, Utkal University, Vani Vihar, Bhubaneswar 751004, Orissa (India)


    The multi-elemental composition of in vitro-proliferated root tissues of Andrographis paniculata (Burm.f.) Wall. ex Nees was compared with that of the naturally grown in vivo plants. Trace elements namely Cr, Mn, Fe, Co, Ni, Cu, Zn, Se, Rb, Sr and Pb in addition to two macro-elements K and Ca were identified and quantified in root tissues of both sources using the energy dispersive X-ray fluorescence (ED-XRF) technique. ED-XRF analysis was performed using Mo K X-rays generated from a secondary molybdenum target. The elemental content of in vitro roots was found to be at par with that of naturally grown plants of the same species. This opens up a possibility of exploiting in vitro root cultures as a viable, alternative and renewable source of phytochemicals of relevance, besides providing a means for conservation of the valuable natural resources.

  8. [An improved morphological edge detection algorithm of medical image based on multi-structure element]. (United States)

    Luo, Xiaogang; Liu, Ting; Peng, Chenglin; Wen, Li


    An improved edge detection algorithm is proposed in this paper for the medical images with strong noises and fuzzy edges. The algorithm modified the combination of morphological operations, so that the unclear edges of the images are avoided. In this paper is also introduced the algorithm of multi-structure elements which can reserve integrated edges from different directions of the images. Furthermore, the contrast enhancement and morphological filter processing are implemented. This method can detect the edges efficiently, keep the detected edges smooth and obtain coherent image edges. Experiments demonstrate that this edge detector has a better performance of noise reduction and keeps the edges more accurate than do the traditional edge detectors; thus its practicality is enhanced.

  9. Nuclear structure effects in quasifission – understanding the formation of the heaviest elements

    Directory of Open Access Journals (Sweden)

    Hinde D. J.


    Full Text Available Quasifission is an important process suppressing the fusion of two heavy nuclei in reactions used to create superheavy elements. Quasifission results in rapid separation of the dinuclear system initially formed at contact. Achieving reliable a priori prediction of quasifission probabilities is a very diffcult problem. Through measurements with projectiles from C to Ni, the Australian National University’s Heavy Ion Accelerator Facility and CUBE spectrometer have been used to map out mass-angle distributions (MAD - the fission mass-ratio as a function of centre-of-mass angle. These provide information on quasifission dynamics in the least modeldependent way. Average quasifission time-scales have been extracted, and compared with TDHF calculations of the collisions, with good agreement being found. With the baseline information from the survey of experimental MAD, strong influences of the nuclear structure of the projectile and target nuclei can be clearly determined.

  10. Mixed variational formulations of finite element analysis of elastoacoustic/slosh fluid-structure interaction (United States)

    Felippa, Carlos A.; Ohayon, Roger


    A general three-field variational principle is obtained for the motion of an acoustic fluid enclosed in a rigid or flexible container by the method of canonical decomposition applied to a modified form of the wave equation in the displacement potential. The general principle is specialized to a mixed two-field principle that contains the fluid displacement potential and pressure as independent fields. This principle contains a free parameter alpha. Semidiscrete finite-element equations of motion based on this principle are displayed and applied to the transient response and free-vibrations of the coupled fluid-structure problem. It is shown that a particular setting of alpha yields a rich set of formulations that can be customized to fit physical and computational requirements. The variational principle is then extended to handle slosh motions in a uniform gravity field, and used to derive semidiscrete equations of motion that account for such effects.

  11. Mixed variational formulation of finite element analysis of acoustoelastic/slosh fluid-structure interaction (United States)

    Felippa, C. A.; Ohayon, R.


    A general three-field variational principle is obtained for the motion of an acoustic fluid enclosed in a rigid or flexible container by the method of canonical decomposition applied to a modified form of the wave equation in the displacement potential. The general principle is specialized to a mixed two-field principle that contains the fluid displacement potential and pressure as independent fields. This principle contains a free parameter alpha. Semidiscrete finite-element equations of motion based on this principle are displayed and applied to the transient response and free-vibrations of the coupled fluid-structure problem. It is shown that a particular setting of alpha yields a rich set of formulations that can be customized to fit physical and computational requirements. The variational principle is then extended to handle slosh motions in a uniform gravity field, and used to derived semidiscrete equations of motion that account for such effects.

  12. Finite Element Analysis of Doorframe Structure of Single Oblique Pole Type in Container Crane (United States)

    Cheng, X. F.; Wu, F. Q.; Tang, G.; Hu, X.


    Compared with the composite type, the single oblique pole type has more advantages, such as simple structure, thrift steel and high safe overhead clearance. The finite element model of the single oblique pole type is established in nodes by ANSYS, and more details are considered when the model is simplified, such as the section of Girder and Boom, torque in Girder and Boom occurred by Machinery house and Trolley, density according to the way of simplification etc. The stress and deformation of ten observation points are compared and analyzed, when the trolley is in nine dangerous positions. Based on the result of analysis, six dangerous points are selected to provide reference for the detection and evaluation of container crane.

  13. Typical structural elements of seismicity and impact crater morphology identified in GIS ENDDB digital models. (United States)

    Mikheeva, Anna


    The subject database of the ENDDB system (Earth's Natural Disasters Database) is a combination of the EISC catalog (Earth's impact structures Catalog [1]) and seismological data of more than 60 earthquake catalogs (EC). ENDDB geographic subsystem uses the NASA ASTER GDEM data arrays to obtain a high-resolution (1 arc-second) shaded relief model, as well as the digital mapping technology, which consists in shading surface points according to their brightness controlled by the illumination angle. For example, the identifying impact craters by means of ENDDB begins with selecting the optimum base colors of the image, the parameters of illumination and shadow depth for constructing a shaded model on a regular grid of values. This procedure allows obtaining precise 3D images of the terrain and gravity patterns, and, moreover, furnishes data for recognizing standard morphological elements according to which impact structures can be visually detected. For constructing a shaded gravity anomaly with the ENDDB tools, Global marine gravity data (of models V16.1 and V18.1 [2]) are embedded into the system. These models, which are arrays of gravity pixel values, are of the resolution increased from the equator to the poles, being 30 arc-seconds per point on average. This resolution is the same as in the more recent V21.1 model. Due to these data, new morphological elements typical of impact structures, which are expressed in the shaded elevation and gravity models (identified using the ENDDB visualization tools) was found and compared in hundreds of craters from the EISC-catalog: tail-shaped asymmetry of relief, heart-shaped geometry of craters, and tail-shaped gravity lows [3] and so on. New diagnostic criteria associated with typical morphological elements revealed with advanced image processing technologies are very important to confirm the impact origin for many potential craters. The basic hypothesis of the impact-explosive tectonics [4] is that meteorite craters on the

  14. Structured populations of Sulfolobus acidocaldarius with susceptibility to mobile genetic elements (United States)

    Anderson, Rika E.; Kouris, Angela; Seward, Christopher H.; Campbell, Kate M.; Whitaker, Rachel J.


    The impact of a structured environment on genome evolution can be determined through comparative population genomics of species that live in the same habitat. Recent work comparing three genome sequences of Sulfolobus acidocaldarius suggested that highly structured, extreme, hot spring environments do not limit dispersal of this thermoacidophile, in contrast to other co-occurring Sulfolobus species. Instead, a high level of conservation among these three S. acidocaldarius genomes was hypothesized to result from rapid, global-scale dispersal promoted by low susceptibility to viruses that sets S. acidocaldarius apart from its sister Sulfolobus species. To test this hypothesis, we conducted a comparative analysis of 47 genomes of S. acidocaldarius from spatial and temporal sampling of two hot springs in Yellowstone National Park. While we confirm the low diversity in the core genome, we observe differentiation among S. acidocaldarius populations, likely resulting from low migration among hot spring “islands” in Yellowstone National Park. Patterns of genomic variation indicate that differing geological contexts result in the elimination or preservation of diversity among differentiated populations. We observe multiple deletions associated with a large genomic island rich in glycosyltransferases, differential integrations of the Sulfolobus turreted icosahedral virus, as well as two different plasmid elements. These data demonstrate that neither rapid dispersal nor lack of mobile genetic elements result in low diversity in the S. acidocaldariusgenomes. We suggest instead that significant differences in the recent evolutionary history, or the intrinsic evolutionary rates, of sister Sulfolobusspecies result in the relatively low diversity of the S. acidocaldarius genome.

  15. Engineered, highly reactive substrates of microbial transglutaminase enable protein labeling within various secondary structure elements. (United States)

    Rachel, Natalie M; Quaglia, Daniela; Lévesque, Éric; Charette, André B; Pelletier, Joelle N


    Microbial transglutaminase (MTG) is a practical tool to enzymatically form isopeptide bonds between peptide or protein substrates. This natural approach to crosslinking the side-chains of reactive glutamine and lysine residues is solidly rooted in food and textile processing. More recently, MTG's tolerance for various primary amines in lieu of lysine have revealed its potential for site-specific protein labeling with aminated compounds, including fluorophores. Importantly, MTG can label glutamines at accessible positions in the body of a target protein, setting it apart from most labeling enzymes that react exclusively at protein termini. To expand its applicability as a labeling tool, we engineered the B1 domain of Protein G (GB1) to probe the selectivity and enhance the reactivity of MTG toward its glutamine substrate. We built a GB1 library where each variant contained a single glutamine at positions covering all secondary structure elements. The most reactive and selective variants displayed a >100-fold increase in incorporation of a recently developed aminated benzo[a]imidazo[2,1,5-cd]indolizine-type fluorophore, relative to native GB1. None of the variants were destabilized. Our results demonstrate that MTG can react readily with glutamines in α-helical, β-sheet, and unstructured loop elements and does not favor one type of secondary structure. Introducing point mutations within MTG's active site further increased reactivity toward the most reactive substrate variant, I6Q-GB1, enhancing MTG's capacity to fluorescently label an engineered, highly reactive glutamine substrate. This work demonstrates that MTG-reactive glutamines can be readily introduced into a protein domain for fluorescent labeling. © 2017 The Protein Society.


    Energy Technology Data Exchange (ETDEWEB)

    Hakan Ozaltun; Herman Shen; Pavel Madvedev


    This article presents numerical simulation of dispersion fuel mini plates via fluid–thermal–structural interaction performed by commercial finite element solver COMSOL Multiphysics to identify initial mechanical response under actual operating conditions. Since fuel particles are dispersed in Aluminum matrix, and temperatures during the fabrication process reach to the melting temperature of the Aluminum matrix, stress/strain characteristics of the domain cannot be reproduced by using simplified models and assumptions. Therefore, fabrication induced stresses were considered and simulated via image based modeling techniques with the consideration of the high temperature material data. In order to identify the residuals over the U7Mo particles and the Aluminum matrix, a representative SEM image was employed to construct a microstructure based thermo-elasto-plastic FE model. Once residuals and plastic strains were identified in micro-scale, solution was used as initial condition for subsequent multiphysics simulations at the continuum level. Furthermore, since solid, thermal and fluid properties are temperature dependent and temperature field is a function of the velocity field of the coolant, coupled multiphysics simulations were considered. First, velocity and pressure fields of the coolant were computed via fluidstructural interaction. Computed solution for velocity fields were used to identify the temperature distribution on the coolant and on the fuel plate via fluid-thermal interaction. Finally, temperature fields and residual stresses were used to obtain the stress field of the plates via fluid-thermal-structural interaction.

  17. Development of a thermal and structural model for a NASTRAN finite-element analysis of a hypersonic wing test structure (United States)

    Lameris, J.


    The development of a thermal and structural model for a hypersonic wing test structure using the NASTRAN finite-element method as its primary analytical tool is described. A detailed analysis was defined to obtain the temperature and thermal stress distribution in the whole wing as well as the five upper and lower root panels. During the development of the models, it was found that the thermal application of NASTRAN and the VIEW program, used for the generation of the radiation exchange coefficients, were definicent. Although for most of these deficiencies solutions could be found, the existence of one particular deficiency in the current thermal model prevented the final computation of the temperature distributions. A SPAR analysis of a single bay of the wing, using data converted from the original NASTRAN model, indicates that local temperature-time distributions can be obtained with good agreement with the test data. The conversion of the NASTRAN thermal model into a SPAR model is recommended to meet the immediate goal of obtaining an accurate thermal stress distribution.

  18. Nanoscale dose deposition in cell structures under X-ray irradiation treatment assisted with nanoparticles of a set of elements: an analytical approach to cell survival

    Energy Technology Data Exchange (ETDEWEB)

    Melo B, W.; Barboza F, M. [Universidad de Sonora, Departamento de Investigacion en Fisica, 83000 Hermosillo, Sonora (Mexico); Chernov, G., E-mail: [Universidad de Sonora, Departamento de Fisica, 83000 Hermosillo, Sonora (Mexico)


    The goal of combining nanoparticles (Nps) with radiation therapy is to increase the differential effect between healthy and tumor tissues. Only some elements have been investigated to be used as radiosensitizers and no systematic experimental or theoretical comparisons between different materials have been developed. MacMahon, et al. (Nano scale, 2016, 8, 581) presents the first systematic computational study of the impact of elemental composition on nanoparticle radiation interaction for kilo voltage and megavoltage X-ray exposure, for a range of elements (Z = 14 - 80). In this study we present and analytical model to assess the cell survival modification responses of cell cultures under irradiation treatments with keV X-rays assisted with Nps of different materials as platinum, hafnium, gadolinium, gold, germanium, iodine and iron. This model starts from the data of radial dose deposition around a single 20 nm diameter Np irradiated with photons of an energy 20 keV higher than the element K-shell binding energy to the nano scale probability of dose distribution inside cell structures with embedded Nps (the assessment of the average dose and the average squared dose in cell structure). Also based on the Local Effect Model we estimate potential biological effects, as is the case of the Relative Biological Effectiveness (RBE). Nano scale dose deposition exhibits a complex dependence on atomic number, as a consequence of the variations in secondary Auger electron spectra, this is manifested in significant variations in RBE. Upon in vitro experiments RBE varies from 1 to 1.6. Values representative of a high radiosensitization were observed for lower energies, ones that are well reproduced by our analytical analysis for cell cultures with a homogeneous distribution of different material Nps. (Author)


    Directory of Open Access Journals (Sweden)

    F. Panteleenko


    Full Text Available The paper presents results of investigations on structure and mechanical properties of technological equipment elements made of heat-resistant steels. A scale of chrome and molybdenum steel microstructure degradation based on evaluation of  coagulated carbide size and material mechanical properties (a point from 0-operation without time limits, up to 4-operation prohibition has been proposed in the paper. It has been  established that an analysis of  steel microstructure directly on equipment elements by means of a portable microscope is an efficient express method for evaluation of equipment condition and structures due to control of material structure degradation rate of a diagnosed object.

  20. Structural color and its interaction with other color-producing elements: perspectives from spiders (United States)

    Hsiung, Bor-Kai; Blackledge, Todd A.; Shawkey, Matthew D.


    Structural color is produced when nanostructures called schemochromes alter light reflected from a surface through different optic principles, in contrast with other types of colors that are produced when pigments selectively absorb certain wavelengths of light. Research on biogenic photonic nanostructures has focused primarily on bird feathers, butterfly wings and beetle elytra, ignoring other diverse groups such as spiders. We argue that spiders are a good model system to study the functions and evolution of colors in nature for the following reasons. First, these colors clearly function in spiders such as the tarantulas outside of sexual selection, which is likely the dominant driver of the evolution of structural colors in birds and butterflies. Second, within more than 44,000 currently known spider species, colors are used in every possible way based on the same sets of relatively simple materials. Using spiders, we can study how colors evolve to serve different functions under a variety of combinations of driving forces, and how those colors are produced within a relatively simple system. Here, we first review the different color-producing materials and mechanisms (i.e., light absorbing, reflecting and emitting) in birds, butterflies and beetles, the interactions between these different elements, and the functions of colors in different organisms. We then summarize the current state of knowledge of spider colors and compare it with that of birds and insects. We then raise questions including: 1. Could spiders use fluorescence as a mechanism to protect themselves from UV radiation, if they do not have the biosynthetic pathways to produce melanins? 2. What functions could color serve for nearly blind tarantulas? 3. Why are only multilayer nanostructures (thus far) found in spiders, while birds and butterflies use many diverse nanostructures? And, does this limit the diversity of structural colors found in spiders? Answering any of these questions in the future

  1. The crystal structure of titanium dioxide nanoparticles influences immune activity in vitro and in vivo. (United States)

    Vandebriel, Rob J; Vermeulen, Jolanda P; van Engelen, Laurens B; de Jong, Britt; Verhagen, Lisa M; de la Fonteyne-Blankestijn, Liset J; Hoonakker, Marieke E; de Jong, Wim H


    The use of engineered nanoparticles (NP) is widespread and still increasing. There is a great need to assess their safety. Newly engineered NP enter the market in a large variety; therefore safety evaluation should preferably be in a high-throughput fashion. In vitro screening is suitable for this purpose. TiO 2 NP exist in a large variety (crystal structure, coating and size), but information on their relative toxicities is scarce. TiO 2 NP may be inhaled by workers in e.g. paint production and application. In mice, inhalation of TiO 2 NP increases allergic reactions. Dendritic cells (DC) form an important part of the lung immune system, and are essential in adjuvant activity. The present study aimed to establish the effect of a variety of TiO 2 NP on DC maturation in vitro. Two NP of different crystal structure but similar in size, uncoated and from the same supplier, were evaluated for their adjuvant activity in vivo. Immature DC were differentiated in vitro from human peripheral blood monocytes. Exposure effects of a series of fourteen TiO 2 NP on cell viability, CD83 and CD86 expression, and IL-12p40 and TNF-α production were measured. BALB/c mice were intranasally sensitized with ovalbumin (OVA) alone, OVA plus anatase TiO 2 NP, OVA plus rutile TiO 2 NP, and OVA plus Carbon Black (CB; positive control). The mice were intranasally challenged with OVA. OVA-specific IgE and IgG1 in serum, cellular inflammation in bronchoalveolar lavage fluid (BALF) and IL-4 and IL-5 production in draining bronchial lymph nodes were evaluated. All NP dispersions contained NP aggregates. The anatase NP and anatase/rutile mixture NP induced a higher CD83 and CD86 expression and a higher IL-12p40 production in vitro than the rutile NP (including coated rutile NP and a rutile NP of a 10-fold larger primary diameter). OVA-specific serum IgE and IgG1 were increased by anatase NP, rutile NP, and CB, in the order rutile

  2. Creating a Test Validated Structural Dynamic Finite Element Model of the Multi-Utility Technology Test Bed Aircraft (United States)

    Pak, Chan-Gi; Truong, Samson S.


    Small modeling errors in the finite element model will eventually induce errors in the structural flexibility and mass, thus propagating into unpredictable errors in the unsteady aerodynamics and the control law design. One of the primary objectives of Multi Utility Technology Test Bed, X-56A, aircraft is the flight demonstration of active flutter suppression, and therefore in this study, the identification of the primary and secondary modes for the structural model tuning based on the flutter analysis of X-56A. The ground vibration test validated structural dynamic finite element model of the X-56A is created in this study. The structural dynamic finite element model of the X-56A is improved using a model tuning tool. In this study, two different weight configurations of the X-56A have been improved in a single optimization run.

  3. Prion structure investigated in situ, ex vivo, and in vitro by FTIR spectroscopy (United States)

    Kneipp, Janina; Miller, Lisa M.; Spassov, Sashko; Sokolowski, Fabian; Lasch, Peter; Beekes, Michael; Naumann, Dieter


    Syrian hamster nervous tissue was investigated by FTIR microspectroscopy with conventional and synchrotron infrared light sources. Various tissue structures from the cerebellum and medulla oblongata of scrapie-infected and control hamsters were investigated at a spatial resolution of 50 μm. Single neurons in dorsal root ganglia of scrapie-infected hamsters were analyzed by raster scan mapping at 6 μm spatial resolution. These measurements enabled us to (i) scrutinize structural differences between infected and non-infected tissue and (ii) analyze for the first time the distribution of different protein structures in situ within single nerve cells. Single nerve cells exhibited areas of increased β-sheet content, which co-localized consistently with accumulations of the pathological prion protein (PrPSc). Spectral data were also obtained from purified, partly proteinase K digested PrPSc isolated from scrapie-infected nervous tissue of hamsters to elucidate similarities/dissimilarities between prion structure in situ and ex vivo. A further comparison is drawn to the recombinant Syrian hamster prion protein SHaPrP90-232, whose in vitro transition from the predominantly a-helical isoform to β-sheet rich oligomeric structures was also investigated by FTIR spectroscopy.

  4. STARS: An Integrated, Multidisciplinary, Finite-Element, Structural, Fluids, Aeroelastic, and Aeroservoelastic Analysis Computer Program (United States)

    Gupta, K. K.


    A multidisciplinary, finite element-based, highly graphics-oriented, linear and nonlinear analysis capability that includes such disciplines as structures, heat transfer, linear aerodynamics, computational fluid dynamics, and controls engineering has been achieved by integrating several new modules in the original STARS (STructural Analysis RoutineS) computer program. Each individual analysis module is general-purpose in nature and is effectively integrated to yield aeroelastic and aeroservoelastic solutions of complex engineering problems. Examples of advanced NASA Dryden Flight Research Center projects analyzed by the code in recent years include the X-29A, F-18 High Alpha Research Vehicle/Thrust Vectoring Control System, B-52/Pegasus Generic Hypersonics, National AeroSpace Plane (NASP), SR-71/Hypersonic Launch Vehicle, and High Speed Civil Transport (HSCT) projects. Extensive graphics capabilities exist for convenient model development and postprocessing of analysis results. The program is written in modular form in standard FORTRAN language to run on a variety of computers, such as the IBM RISC/6000, SGI, DEC, Cray, and personal computer; associated graphics codes use OpenGL and IBM/graPHIGS language for color depiction. This program is available from COSMIC, the NASA agency for distribution of computer programs.

  5. Prony series spectra of structural relaxation in N-BK7 for finite element modeling. (United States)

    Koontz, Erick; Blouin, Vincent; Wachtel, Peter; Musgraves, J David; Richardson, Kathleen


    Structural relaxation behavior of N-BK7 glass was characterized at temperatures 20 °C above and below T(12) for this glass, using a thermo mechanical analyzer (TMA). T(12) is a characteristic temperature corresponding to a viscosity of 10(12) Pa·s. The glass was subject to quick temperature down-jumps preceded and followed by long isothermal holds. The exponential-like decay of the sample height was recorded and fitted using a unique Prony series method. The result of his method was a plot of the fit parameters revealing the presence of four distinct peaks or distributions of relaxation times. The number of relaxation times decreased as final test temperature was increased. The relaxation times did not shift significantly with changing temperature; however, the Prony weight terms varied essentially linearly with temperature. It was also found that the structural relaxation behavior of the glass trended toward single exponential behavior at temperatures above the testing range. The result of the analysis was a temperature-dependent Prony series model that can be used in finite element modeling of glass behavior in processes such as precision glass molding (PGM).

  6. Structural elements of ancient armies of Northern Black Sea Region: ethnic, social and functional peculiarities

    Directory of Open Access Journals (Sweden)

    K. M. Kolesnykov


    Full Text Available This article deal with the description, analysis and generalization of features organization of command structure of the army ancient states of the Northern Black Sea region: Olbia, Chersonese, Bosporus. Author sure that the foundation of the armed forces of these states was a civil militia – free, economically independent landowners, endowed with the broadest volume of political and social rights men – full citizens. Accordingly, the assemblies of citizens were electing strategists, who led militia forces. In case of need the people also claimed commanders’ mercenary troops. Bosporus kings have attracted a significant number of hired troops that held by the royal treasury income and special direct tax. Some structural elements of ancient armies had different ethnic origin and could specialize in different types of weapons. For example, the Scythians mainly famous as archers (bowmen, “toxots”, Sarmatians – heavy horsemen (“cataphractarii”, the Celts – shield-holders and swordsman (“thyureoforoi” etc. Representatives of the Bosporus aristocratic families, who served in the army, came from Hellenic and barbarian ethnic groups. For example, in the Roman period on the Bosporus fixed formation units of cathafractarian cavalry. The weapons and tactics of the Sarmatian nomadic nobility (Aspurhianian, Sirak, Aorsy and more were served as a model for Bosporus cataphractarian horsemen. Among the military allies of the ancient states of the Northern Black Sea region were leaders of local tribes, the barbarian lords of neighboring countries and the powerful monarchs of Pontus and Rome.

  7. Investigation of the overconsolidation and structural behavior of Shanghai clays by element testing and constitutive modeling

    Directory of Open Access Journals (Sweden)

    Guan-lin Ye


    Full Text Available The mechanical properties and constitutive modeling of Shanghai clays are very important for numerical analysis on geotechnical engineering in Shanghai, where continuous layers of soft clays run 30–40 m deep. The clays are divided into 5 major layers. A series of laboratory tests are carried out to investigate their mechanical properties. The top and bottom layers are overconsolidated hard clays, and the middle layers are normally consolidated or lightly overconsolidated sensitive marine clays. A constitutive model, which can describe the overconsolidation and structure of soils using only 8 parameters, is modified to simulate the test results. A rational procedure to determine the values of the material parameters and initial conditions is also proposed. The model is able to effectively reproduce both one-dimensional (1D consolidation and drained/undrained triaxial test results of Shanghai clays, with one set of parameters for each layer. From element testing and constitutive modeling, two findings are obtained. First, the decay rates of overconsolidation are smaller in overconsolidated layers than in normally consolidated layers. Second, the natural microstructure of layer 4 is relatively stable, that is, a large degree of structure is still maintained in the specimen even after 1D consolidation and drained triaxial tests. The modified model and obtained parameter values can be used for numerical analysis of geotechnical projects in Shanghai.

  8. Performance and Risk Assessment of Soil-Structure Interaction Systems Based on Finite Element Reliability Methods

    Directory of Open Access Journals (Sweden)

    Quan Gu


    Full Text Available In the context of performance-based earthquake engineering, reliability method has been of significant importance in performance and risk assessment of structures or soil-structure interaction (SSI systems. The finite element (FE reliability method combines FE analysis with state-of-the-art methods in reliability analysis and has been employed increasingly to estimate the probability of occurrence of failure events corresponding to various hazard levels (e.g., earthquakes with various intensity. In this paper, crucial components for FE reliability analysis are reviewed and summarized. Furthermore, recent advances in both time invariant and time variant reliability analysis methods for realistic nonlinear SSI systems are presented and applied to a two-dimensional two story building on layered soil. Various time invariant reliability analysis methods are applied, including the first-order reliability method (FORM, importance sampling method, and orthogonal plane sampling (OPS method. For time variant reliability analysis, an upper bound of the failure probability is obtained from numerical integration of the mean outcrossing rate (MOCR. The MOCR is computed by using FORM analysis and OPS analysis. Results by different FE reliability methods are compared in terms of accuracy and computational cost. This paper provides valuable insights for reliability based probabilistic performance and risk assessment of SSI systems.

  9. A structure-based Multiple-Instance Learning approach to predicting in vitro transcription factor-DNA interaction. (United States)

    Gao, Zhen; Ruan, Jianhua


    Understanding the mechanism of transcriptional regulation remains an inspiring stage of molecular biology. Recently, in vitro protein-binding microarray experiments have greatly improved the understanding of transcription factor-DNA interaction. We present a method - MIL3D - which predicts in vitro transcription factor binding by multiple-instance learning with structural properties of DNA. Evaluation on in vitro data of twenty mouse transcription factors shows that our method outperforms a method based on simple-instance learning with DNA structural properties, and the widely used k-mer counting method, for nineteen out of twenty of the transcription factors. Our analysis showed that the MIL3D approach can utilize subtle structural similarities when a strong sequence consensus is not available. Combining multiple-instance learning and structural properties of DNA has promising potential for studying biological regulatory networks.

  10. Inferring global Upper-Mantle Shear Attenuation structure by waveform tomography using the Spectral Element Method (United States)

    Karaoǧlu, Haydar; Romanowicz, Barbara


    We present a global upper-mantle shear wave attenuation model that is built through a hybrid full-waveform inversion algorithm applied to long-period waveforms, using the Spectral Element Method for wavefield computations. Our inversion strategy is based on an iterative approach that involves the inversion for successive updates in the attenuation parameter (δ Q^{-1}_μ) and elastic parameters (isotropic velocity VS, and radial anisotropy parameter ξ) through a Gauss-Newton type optimization scheme that employs envelope- and waveform-type misfit functionals for the two steps, respectively. We also include source and receiver terms in the inversion steps for attenuation structure. We conducted a total of 8 iterations (6 for attenuation and 2 for elastic structure), and one inversion for updates to source parameters. The starting model included the elastic part of the relatively high resolution 3-D whole mantle seismic velocity model, SEMUCB-WM1, which served to account for elastic focusing effects. The data set is a subset of the three component surface waveform data set, filtered between 400 and 60 s, that contributed to the construction of the whole-mantle tomographic model SEMUCB-WM1. We applied strict selection criteria to this data set for the attenuation iteration steps, and investigated the effect of attenuation crustal structure on the retrieved mantle attenuation structure. While a constant 1-D Qμ model with a constant value of 165 throughout the upper-mantle was used as starting model for attenuation inversion, we were able to recover, in depth extent and strength, the high attenuation zone present in the depth range 80-200 km. The final three-dimensional model, SEMUCB-UMQ, shows strong correlation with tectonic features down to 200˜250 km depth, with low attenuation beneath the cratons, stable parts of continents and regions of old oceanic crust, and high attenuation along mid-ocean ridges and back-arcs. Below 250 km, we observe strong attenuation in

  11. The Impact of Structural and Process Elements of Pre-school and Primary School Environments on Children's Cognitive Development at Four Years of Age


    Moore, Nodlaig


    The structural and process elements of the early years classroom have contributed to much research in the area of early childhood education. Structural elements have been referred to as regulatable features that are “assumed to indirectly affect the child” (Burchinal, Roberts, Nabors & Bryant et al 1990). Process elements are directly related to children’s experiences and are “more difficult if not impossible to regulate” (Howes, Phillips & Whitebook 1992, p. 480). The structural elements of ...

  12. Static aeroelastic analysis of wings using Euler/Navier-Stokes equations coupled with improved wing-box finite element structures (United States)

    Guruswamy, Guru P.; MacMurdy, Dale E.; Kapania, Rakesh K.


    Strong interactions between flow about an aircraft wing and the wing structure can result in aeroelastic phenomena which significantly impact aircraft performance. Time-accurate methods for solving the unsteady Navier-Stokes equations have matured to the point where reliable results can be obtained with reasonable computational costs for complex non-linear flows with shock waves, vortices and separations. The ability to combine such a flow solver with a general finite element structural model is key to an aeroelastic analysis in these flows. Earlier work involved time-accurate integration of modal structural models based on plate elements. A finite element model was developed to handle three-dimensional wing boxes, and incorporated into the flow solver without the need for modal analysis. Static condensation is performed on the structural model to reduce the structural degrees of freedom for the aeroelastic analysis. Direct incorporation of the finite element wing-box structural model with the flow solver requires finding adequate methods for transferring aerodynamic pressures to the structural grid and returning deflections to the aerodynamic grid. Several schemes were explored for handling the grid-to-grid transfer of information. The complex, built-up nature of the wing-box complicated this transfer. Aeroelastic calculations for a sample wing in transonic flow comparing various simple transfer schemes are presented and discussed.

  13. Effects of germination and high hydrostatic pressure processing on mineral elements, amino acids and antioxidants in vitro bioaccessibility, as well as starch digestibility in brown rice (Oryza sativa L.). (United States)

    Xia, Qiang; Wang, Liping; Xu, Congcong; Mei, Jun; Li, Yunfei


    The effects of germination and high hydrostatic pressure (HHP) processing on the in vitro bioaccessibility of mineral elements, amino acids (AAs), antioxidants and starch in brown rice (BR) were investigated. Germinated BR (GBR) was obtained by incubating at 37°C for 36h and then subjected to HHP treatments at 0.1, 100, 300 and 500MPa for 10min. The in vitro bioaccessibility of calcium and copper was increased by 12.59-52.17% and 2.87-23.06% after HHP, respectively, but bioaccessible iron was decreased. In addition, HHP significantly improved individual AAs, particularly indispensable AAs and gama-aminobutyric acid, as well as bioaccessible total antioxidant activities and starch resistance to enzymatic hydrolysis. However, germination greatly increased starch digestibility. Atomic force microscopy characterization suggested an obvious structural change in bran fraction at pressures above 300MPa. These results can help to understand the effects of germination and HHP technologies on nutrients bioaccessibility and develop appropriate processing conditions. Copyright © 2016. Published by Elsevier Ltd.

  14. Simulation of planar soft tissues using a structural constitutive model: Finite element implementation and validation. (United States)

    Fan, Rong; Sacks, Michael S


    Computational implementation of physical and physiologically realistic constitutive models is critical for numerical simulation of soft biological tissues in a variety of biomedical applications. It is well established that the highly nonlinear and anisotropic mechanical behaviors of soft tissues are an emergent behavior of the underlying tissue microstructure. In the present study, we have implemented a structural constitutive model into a finite element framework specialized for membrane tissues. We noted that starting with a single element subjected to uniaxial tension, the non-fibrous tissue matrix must be present to prevent unrealistic tissue deformations. Flexural simulations were used to set the non-fibrous matrix modulus because fibers have little effects on tissue deformation under three-point bending. Multiple deformation modes were simulated, including strip biaxial, planar biaxial with two attachment methods, and membrane inflation. Detailed comparisons with experimental data were undertaken to insure faithful simulations of both the macro-level stress-strain insights into adaptations of the fiber architecture under stress, such as fiber reorientation and fiber recruitment. Results indicated a high degree of fidelity and demonstrated interesting microstructural adaptions to stress and the important role of the underlying tissue matrix. Moreover, we apparently resolve a discrepancy in our 1997 study (Billiar and Sacks, 1997. J. Biomech. 30 (7), 753-756) where we observed that under strip biaxial stretch the simulated fiber splay responses were not in good agreement with the experimental results, suggesting non-affine deformations may have occurred. However, by correctly accounting for the isotropic phase of the measured fiber splay, good agreement was obtained. While not the final word, these simulations suggest that affine fiber kinematics for planar collagenous tissues is a reasonable assumption at the macro level. Simulation tools such as these are

  15. Elements of metacommunity structure in Amazonian Zygoptera among streams under different spatial scales and environmental conditions. (United States)

    Brasil, Leandro Schlemmer; Vieira, Thiago Bernardi; de Oliveira-Junior, José Max Barbosa; Dias-Silva, Karina; Juen, Leandro


    An important aspect of conservation is to understand the founding elements and characteristics of metacommunities in natural environments, and the consequences of anthropogenic disturbance on these patterns. In natural Amazonian environments, the interfluves of the major rivers play an important role in the formation of areas of endemism through the historical isolation of species and the speciation process. We evaluated elements of metacommunity structure for Zygoptera (Insecta: Odonata) sampled in 93 Amazonian streams distributed in two distinct biogeographic regions (areas of endemism). Of sampled streams, 43 were considered to have experienced negligible anthropogenic impacts, and 50 were considered impacted by anthropogenic activities. Our hypothesis was that preserved ("negligible impact") streams would present a Clementsian pattern, forming clusters of distinct species, reflecting the biogeographic pattern of the two regions, and that anthropogenic streams would present random patterns of metacommunity, due to the loss of more sensitive species and dominance of more tolerant species, which have higher dispersal ability and environmental tolerance. In negligible impact streams, the Clementsian pattern reflected a strong biogeographic pattern, which we discuss considering the areas of endemism of Amazonian rivers. As for communities in human-impacted streams, a biotic homogenization was evident, in which rare species were suppressed and the most common species had become hyper-dominant. Understanding the mechanisms that trigger changes in metacommunities is an important issue for conservation, because they can help create mitigation measures for the impacts of anthropogenic activities on biological communities, and so should be expanded to studies using other taxonomic groups in both tropical and temperate systems, and, wherever possible, at multiple spatial scales.

  16. Underground Parking structure built with deep foundations and vault precast elements in Spain

    Directory of Open Access Journals (Sweden)

    Fernández-Ordóñez, D.


    Full Text Available In many cases the only places available for the construction of a new car park are the existing streets or roads. These streets may also have important or historic buildings very close to the structure, which means that they cannot be disturbed in any way during the construction of the parking structure. In this particular case, the novelty is that the top deck is solved with a unique structure: a vault that interacts with the pile wall not only for vertical but also for horizontal loads due to the arch mechanism. The construction of the vault is solved as a large precast element of one piece of more than 16 in length and 2.40m in width, which is built in the factory, transported with the help of trucks and erected on site with large cranes.

    En muchos casos las únicas localizaciones para construir aparcamientos son las calles o carreteras. Estas calles también suelen tener alrededor importantes edificios históricos muy cercanos a la propia estructura. En este caso particular la novedad reside en que el forjado superior está resuelto con una estructura especial: una bóveda que interacciona con la pantalla de pilotes no solo en el sentido vertical sino también en el horizontal formando un verdadero mecanismo de arco. La construcción de la bóveda se ha resuelto con grandes elementos prefabricados de una pieza de más de 16m de longitud y de 2,40m de ancho. Se han fabricado en una factoría, transportados y montados en obra con grandes grúas.

  17. In vitro evidence of the structural optimization of the human skeletal bones. (United States)

    Cristofolini, Luca


    Optimization can be seen in a number of human skeletal bones. While there is strong evidence concerning the mechanism at the tissue-level for bone adaptation to the applied loads, the structural optimization at the organ-level is somewhat less clear. This paper reviews the evidence, mainly based on in vitro testing, but also from anatomical and biomechanical considerations, concerning the shape-function relationship in some exemplar cases. The proximal femur is robustly optimized to resist a force applied in a range of directions during daily life, but also to absorb a large amount of energy if an impact is delivered on the greater trochanter during a sideways fall. The diaphysis of the tibia is shaped so as to act as a uniform-stress structure (i.e. structurally efficient) when loaded by a bending moment in the sagittal plane, such as during locomotion. The body of the thoraco-lumbar vertebrae is optimized to resist to a load applied strictly in an axial direction. The result of this review suggests that the structure of bones derives from a combination of local stimulus-driven tissue-level adaptation within the subject, and organ-level generational evolution. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Scaffold with a natural mesh-like architecture: isolation, structural, and in vitro characterization.

    LENUS (Irish Health Repository)

    Burugapalli, Krishna


    An intact extracellular matrix (ECM) with a mesh-like architecture has been identified in the peri-muscular sub-serosal connective tissue (PSCT) of cholecyst (gallbladder). The PSCT layer of cholecyst wall is isolated by mechanical delamination of other layers and decellularized with a treatment with peracetic acid and ethanol solution (PES) in water to obtain the final matrix, which is referred to as cholecyst-derived ECM (CEM). CEM is cross-linked with different concentrations of glutaraldehyde (GA) to demonstrate that the susceptibility of CEM to degradation can be controlled. Quantitative and qualitative macromolecular composition assessments revealed that collagen is the primary structural component of CEM. Elastin is also present. In addition, the ultra-structural studies on CEM reveal the presence of a three-dimensional fibrous mesh-like network structure with similar nanoscale architecture on both mucosal and serosal surfaces. In vitro cell culture studies show that CEM provides a supporting structure for the attachment and proliferation of murine fibroblasts (3T3) and human umbilical vein endothelial cells (HUVEC). CEM is also shown to support the attachment and differentiation of rat adrenal pheochromocytoma cells (PC12).

  19. Stress distribution patterns of implant supported overdentures-analog versus finite element analysis: A comparative in-vitro study. (United States)

    Satpathy, Soumyadev; Babu, C L Satish; Shetty, Shilpa; Raj, Bharat


    The aim of this study was to asses & compare the load transfer characteristics of Ball/O-ring and Bar/Clip attachment systems in implant supported overdentures using analog and finite element analysis models. For the analog part of the study, castable bar was used for the bar and clip attachment and a metallic housing with a rubber O-ring component was used for the ball/O-ring attachment. The stress on the implant surface was measured using the strain-gauge technique. For the finite element analysis, the model were fabricated and load applications were done in a similar manner as in analog study. The difference between both the attachment systems was found to be statistically significant (PO-ring attachment system transmitted lesser amount of stresses to the implants on the non-loading side, as compared to the Bar-Clip attachment system. When overall stress distribution is compared, the Bar-Clip attachment seems to perform better than the Ball/O-ring attachment, because the force was distributed better.

  20. Free Tools and Strategies for the Generation of 3D Finite Element Meshes: Modeling of the Cardiac Structures

    Directory of Open Access Journals (Sweden)

    E. Pavarino


    Full Text Available The Finite Element Method is a well-known technique, being extensively applied in different areas. Studies using the Finite Element Method (FEM are targeted to improve cardiac ablation procedures. For such simulations, the finite element meshes should consider the size and histological features of the target structures. However, it is possible to verify that some methods or tools used to generate meshes of human body structures are still limited, due to nondetailed models, nontrivial preprocessing, or mainly limitation in the use condition. In this paper, alternatives are demonstrated to solid modeling and automatic generation of highly refined tetrahedral meshes, with quality compatible with other studies focused on mesh generation. The innovations presented here are strategies to integrate Open Source Software (OSS. The chosen techniques and strategies are presented and discussed, considering cardiac structures as a first application context.

  1. A Finite Element Method to Predict Adverse Events in Intracranial Stenting Using Microstents: In Vitro Verification and Patient Specific Case Study. (United States)

    Iannaccone, Francesco; De Beule, Matthieu; De Bock, Sander; Van der Bom, Imramsjah M J; Gounis, Matthew J; Wakhloo, Ajay K; Boone, Matthieu; Verhegghe, Benedict; Segers, Patrick


    Clinical studies have demonstrated the efficacy of stent supported coiling for intra-cranial aneurysm treatment. Despite encouraging outcomes, some matters are yet to be addressed. In particular closed stent designs are influenced by the delivery technique and may suffer from under-expansion, with the typical effect of "hugging" the inner curvature of the vessel which seems related to adverse events. In this study we propose a novel finite element (FE) environment to study potential failure able to reproduce the microcatheter "pull-back" delivery technique. We first verified our procedure with published in vitro data and then replicated the intervention on one patient treated with a 4.5 × 22 mm Enterprise microstent (Codman Neurovascular; Raynham MA, USA). Results showed good agreement with the in vitro test, catching both size and location of the malapposed area. A simulation of a 28 mm stent in the same geometry highlighted the impact of the delivery technique, which leads to larger area of malapposition. The patient specific simulation matched the global stent configuration and zones prone to malapposition shown on the clinical images with difference in tortuosity between actual and virtual treatment around 2.3%. We conclude that the presented FE strategy provides an accurate description of the stent mechanics and, after further in vivo validation and optimization, will be a tool to aid clinicians to anticipate the acute procedural outcome avoiding poor initial results.

  2. Hierarchical Structures and Shaped Particles of Bioactive Glass and Its In Vitro Bioactivity

    Directory of Open Access Journals (Sweden)

    U. Boonyang


    Full Text Available In this study, bioactive glass particles with controllable structure and porosity were prepared using dual-templating methods. Block copolymers used as one template component produced mesopores in the calcined samples. Polymer colloidal crystals as the other template component yielded either three-dimensionally ordered macroporous (3DOM products or shaped bioactive glass nanoparticles. The in vitro bioactivity of these bioactive glasses was studied by soaking the samples in simulated body fluid (SBF at body temperature (37°C for varying lengths of time and monitoring the formation of bone-like apatite on the surface of the bioactive glass. A considerable bioactivity was found that all of bioactive glass samples have the ability to induce the formation of an apatite layer on its surface when in contact with SBF. The development of bone-like apatite is faster for 3DOM bioactive glasses than for nanoparticles.

  3. Investigation of the Structure and Element Composition of C-Phycocyanin Extracted from the Microalgae Spirulina platensis

    CERN Document Server

    Mosulishvili, L M; Kirkesali, E I; Khizanishvili, A I; Frontasyeva, M V; Pavlov, S S; Gundorina, S F


    The structure and element composition of C-phycocyanin (C-PC) extracted from the blue-green alga Spirulina platensis were studied. The behavior of structural subunits forming phycobilisomes in the purification process was studied by capillary electrophoresis. Their proportion in high-purity C-PC was determined. The element composition of C-PC of different purity was studied by means of epithermal neutron activation analysis, and metals which may form macromolecular complexes with C-PC were determined (Zn, Cr, Ni, Co, As, Sr, Mo, Ag, Hg). It was shown that contents of toxic metals did not exceed accepted permissible levels for the human organism.

  4. Cellulose as an Architectural Element in Spatially Structured Escherichia coli Biofilms (United States)

    Serra, Diego O.; Richter, Anja M.


    Morphological form in multicellular aggregates emerges from the interplay of genetic constitution and environmental signals. Bacterial macrocolony biofilms, which form intricate three-dimensional structures, such as large and often radially oriented ridges, concentric rings, and elaborate wrinkles, provide a unique opportunity to understand this interplay of “nature and nurture” in morphogenesis at the molecular level. Macrocolony morphology depends on self-produced extracellular matrix components. In Escherichia coli, these are stationary phase-induced amyloid curli fibers and cellulose. While the widely used “domesticated” E. coli K-12 laboratory strains are unable to generate cellulose, we could restore cellulose production and macrocolony morphology of E. coli K-12 strain W3110 by “repairing” a single chromosomal SNP in the bcs operon. Using scanning electron and fluorescence microscopy, cellulose filaments, sheets and nanocomposites with curli fibers were localized in situ at cellular resolution within the physiologically two-layered macrocolony biofilms of this “de-domesticated” strain. As an architectural element, cellulose confers cohesion and elasticity, i.e., tissue-like properties that—together with the cell-encasing curli fiber network and geometrical constraints in a growing colony—explain the formation of long and high ridges and elaborate wrinkles of wild-type macrocolonies. In contrast, a biofilm matrix consisting of the curli fiber network only is brittle and breaks into a pattern of concentric dome-shaped rings separated by deep crevices. These studies now set the stage for clarifying how regulatory networks and in particular c-di-GMP signaling operate in the three-dimensional space of highly structured and “tissue-like” bacterial biofilms. PMID:24097954

  5. SEORious business: structural proteins in sieve tubes and their involvement in sieve element occlusion. (United States)

    Knoblauch, Michael; Froelich, Daniel R; Pickard, William F; Peters, Winfried S


    The phloem provides a network of sieve tubes for long-distance translocation of photosynthates. For over a century, structural proteins in sieve tubes have presented a conundrum since they presumably increase the hydraulic resistance of the tubes while no potential function other than sieve tube or wound sealing in the case of injury has been suggested. Here we summarize and critically evaluate current speculations regarding the roles of these proteins. Our understanding suffers from the suggestive power of images; what looks like a sieve tube plug on micrographs may not actually impede translocation very much. Recent reports of an involvement of SEOR (sieve element occlusion-related) proteins, a class of P-proteins, in the sealing of injured sieve tubes are inconclusive; various lines of evidence suggest that, in neither intact nor injured plants, are SEORs determinative of translocation stoppage. Similarly, the popular notion that P-proteins serve in the defence against phloem sap-feeding insects is unsupported by empirical facts; it is conceivable that in functional sieve tubes, aphids actually could benefit from inducing a plug. The idea that rising cytosolic Ca(2+) generally triggers sieve tube blockage by P-proteins appears widely accepted, despite lacking experimental support. Even in forisomes, P-protein assemblages restricted to one single plant family and the only Ca(2+)-responsive P-proteins known, the available evidence does not unequivocally suggest that plug formation is the cause rather than a consequence of translocation stoppage. We conclude that the physiological roles of structural P-proteins remain elusive, and that in vivo studies of their dynamics in continuous sieve tube networks combined with flow velocity measurements will be required to (hopefully) resolve this scientific roadblock.

  6. Finite Element Model for Thermal-Structural analysis of CLIC Lab Module type 0#2

    CERN Document Server

    Moilanen, Antti; Vamvakas, Alex; Vainola, Jukka Ilmari; Doebert, Steffen


    Temperature changes lead to unwanted thermo-mechanical deformations in the components of the Compact Linear Collider (CLIC) module. There are several sources and sinks of heat around the CLIC two-beam module. Heat is generated in the components that produce, transfer, and extract radio frequency (RF) power. Excess heat is removed from the components by cooling water as well as dissipated to air by convection from the outer surfaces of the components. The ambient temperature might also vary along the tunnel during the operation of CLIC. Due to tight assembling and alignment tolerances, it is necessary to minimize the thermo-mechanical deformations in the components. In this paper, the steps of thermal-structural Finite Element Analysis (FEA) of CLIC lab module type 0#2 are described from geometry model simplification to setting up the simulation. The description is accompanied by useful hints for CATIA and ANSYS users performing similar modelling tasks. A reliable computer simulation is important for studying ...

  7. Structural elements of the signal propagation pathway in squid rhodopsin and bovine rhodopsin. (United States)

    Sugihara, Minoru; Fujibuchi, Wataru; Suwa, Makiko


    Squid and bovine rhodopsins are G-protein coupled receptors (GPCRs) that activate Gq- and Gt-type G-proteins, respectively. To understand the structural elements of the signal propagation pathway, we performed molecular dynamics (MD) simulations of squid and bovine rhodopsins plus a detailed sequence analysis of class A GPCRs. The computations indicate that although the geometry of the retinal is similar in bovine and squid rhodopsins, the important interhelical hydrogen bond networks are different. In squid rhodopsin, an extended hydrogen bond network that spans ∼13 Å to Tyr315 on the cytoplasmic site is present regardless of the protonation state of Asp80. In contrast, the extended hydrogen bond network is interrupted at Tyr306 in bovine rhodopsin. Those differences in the hydrogen bond network may play significant functional roles in the signal propagation from the retinal binding site to the cytoplasmic site, including transmembrane helix (TM) 6 to which the G-protein binds. The MD calculations demonstrate that the elongated conformation of TM6 in squid rhodopsin is stabilized by salt bridges formed with helix (H) 9. Together with the interhelical hydrogen bonds, the salt bridges between TM6 and H9 stabilize the protein conformation of squid rhodopsin and may hinder the occurrence of large conformational changes that are observed upon activation of bovine rhodopsin. © 2011 American Chemical Society

  8. A Practical Approach to Governance and Optimization of Structured Data Elements. (United States)

    Collins, Sarah A; Gesner, Emily; Morgan, Steven; Mar, Perry; Maviglia, Saverio; Colburn, Doreen; Tierney, Diana; Rocha, Roberto


    Definition and configuration of clinical content in an enterprise-wide electronic health record (EHR) implementation is highly complex. Sharing of data definitions across applications within an EHR implementation project may be constrained by practical limitations, including time, tools, and expertise. However, maintaining rigor in an approach to data governance is important for sustainability and consistency. With this understanding, we have defined a practical approach for governance of structured data elements to optimize data definitions given limited resources. This approach includes a 10 step process: 1) identification of clinical topics, 2) creation of draft reference models for clinical topics, 3) scoring of downstream data needs for clinical topics, 4) prioritization of clinical topics, 5) validation of reference models for clinical topics, and 6) calculation of gap analyses of EHR compared against reference model, 7) communication of validated reference models across project members, 8) requested revisions to EHR based on gap analysis, 9) evaluation of usage of reference models across project, and 10) Monitoring for new evidence requiring revisions to reference model.

  9. Effective Simulation of Delamination in Aeronautical Structures Using Shells and Cohesive Elements (United States)

    Davila, Carlos G.; Camanho, Pedro P.; Turon, Albert


    A cohesive element for shell analysis is presented. The element can be used to simulate the initiation and growth of delaminations between stacked, non-coincident layers of shell elements. The procedure to construct the element accounts for the thickness offset by applying the kinematic relations of shell deformation to transform the stiffness and internal force of a zero-thickness cohesive element such that interfacial continuity between the layers is enforced. The procedure is demonstrated by simulating the response and failure of the Mixed Mode Bending test and a skin-stiffener debond specimen. In addition, it is shown that stacks of shell elements can be used to create effective models to predict the inplane and delamination failure modes of thick components. The results indicate that simple shell models can retain many of the necessary predictive attributes of much more complex 3D models while providing the computational efficiency that is necessary for design.

  10. Structural Analysis of Technical-Tactical Elements in Table Tennis and their Role in Different Playing Zones. (United States)

    Munivrana, Goran; Petrinović, Lidija Zekan; Kondrič, Miran


    For the purpose of determining the overall structure of technical-tactical elements in table tennis and evaluating their role in different playing zones around the table, a new measuring instrument (a questionnaire) was formulated that took advantage of the expert knowledge of top, world class table tennis coaches. The results of the hierarchical taxonomic (cluster) analysis showed that the overall structure of the technical-tactical elements forming the table tennis technique could be divided into three basic groups; a group of technical-tactical elements (A) used in the phase of preparing one's own and disabling the opponent's attack; a group of technical-tactical elements (B) used in the phase of attack and counterattack; and a group of technical-tactical elements (C) used in the phase of defense. The differences among the obtained groups of table tennis elements were determined by applying the Kruskal-Wallis test, while relations between the groups and their role in different playing zones around the table were analyzed by comparing the average values of the experts' scores.

  11. Structural Analysis of Technical-Tactical Elements in Table Tennis and their Role in Different Playing Zones

    Directory of Open Access Journals (Sweden)

    Munivrana Goran


    Full Text Available For the purpose of determining the overall structure of technical-tactical elements in table tennis and evaluating their role in different playing zones around the table, a new measuring instrument (a questionnaire was formulated that took advantage of the expert knowledge of top, world class table tennis coaches. The results of the hierarchical taxonomic (cluster analysis showed that the overall structure of the technical-tactical elements forming the table tennis technique could be divided into three basic groups; a group of technical-tactical elements (A used in the phase of preparing one’s own and disabling the opponent’s attack; a group of technical-tactical elements (B used in the phase of attack and counterattack; and a group of technical-tactical elements (C used in the phase of defense. The differences among the obtained groups of table tennis elements were determined by applying the Kruskal-Wallis test, while relations between the groups and their role in different playing zones around the table were analyzed by comparing the average values of the experts’ scores.

  12. Trace Element Compositions and Defect Structures of High-Purity Quartz from the Southern Ural Region, Russia

    Directory of Open Access Journals (Sweden)

    Jens Götze


    Full Text Available Quartz samples of different origin from 10 localities in the Southern Ural region, Russia have been investigated to characterize their trace element compositions and defect structures. The analytical combination of cathodoluminescence (CL microscopy and spectroscopy, electron paramagnetic resonance (EPR spectroscopy, and trace-element analysis by inductively coupled plasma mass spectrometry (ICP-MS revealed that almost all investigated quartz samples showed very low concentrations of trace elements (cumulative concentrations of <50 ppm with <30 ppm Al and <10 ppm Ti and low abundances of paramagnetic defects, defining them economically as “high-purity” quartz (HPQ suitable for high-tech applications. EPR and CL data confirmed the low abundances of substitutional Ti and Fe, and showed Al to be the only significant trace element structurally bound in the investigated quartz samples. CL microscopy revealed a heterogeneous distribution of luminescence centres (i.e., luminescence active trace elements such as Al as well as features of deformation and recrystallization. It is suggested that healing of defects due to deformation-related recrystallization and reorganization processes of the quartz lattice during retrograde metamorphism resulted in low concentrations of CL activator and other trace elements or vacancies, and thus are the main driving processes for the formation of HPQ deposits in the investigated area.

  13. Explicit Dynamic Finite Element Method for Predicting Implosion/Explosion Induced Failure of Shell Structures

    Directory of Open Access Journals (Sweden)

    Jeong-Hoon Song


    Full Text Available A simplified implementation of the conventional extended finite element method (XFEM for dynamic fracture in thin shells is presented. Though this implementation uses the same linear combination of the conventional XFEM, it allows for considerable simplifications of the discontinuous displacement and velocity fields in shell finite elements. The proposed method is implemented for the discrete Kirchhoff triangular (DKT shell element, which is one of the most popular shell elements in engineering analysis. Numerical examples for dynamic failure of shells under impulsive loads including implosion and explosion are presented to demonstrate the effectiveness and robustness of the method.

  14. The structure of floral elements of Anchusa officinalis L. creating attractants for insects

    Directory of Open Access Journals (Sweden)

    Mirosława Chwil


    Full Text Available The present study involved the measurement of size and the micromorphology of the floral elements of Anchusa officinalis L. which are attractants for insects. The structure of the epidermis on the surface of the calyx, petals, throat scales, pistil and nectary were analysed using light and scanning electron microscopy (SEM. For light microscopy observations, semi-permanent slides were prepared, which were treated with Lugol's iodine solution, Sudan III and fluoroglucine. The dark violet lobes of the corolla of Anchusa officinalis, with a velvety surface, and the throat scales, contrasting with them, belong to the most important optical attractants which lure insects from large distances. The dark pink colouring of the sepals additionally increases the attractiveness of the flowers. The epidermis covering the calyx formed different-sized non-glandular trichomes as well as glandular trichomes. The glandular trichomes were composed of a uni - or bicellular leg and a unicellular head. The colour of the corolla petals was determined by anthocyanins accumulated in the epidermal cells and in the more deeply situated parenchyma. The velvety surface was formed by the conical papillae, densely growing from the adaxial epidermis. The pink-violet throat scales with white hairs, covering the inlet to the tube of the corolla, were found at the inlet to the corolla throat. The longest trichomes on the surface of the scales were located in their lower and middle parts, whereas the shortest ones at their tips. The epidermis of the central part of the throat scales formed small papillae. The trichomes had thin cell walls, large vacuoles, numerous plastids and lipid droplets. The two-parted stigma of the pistil was covered by characteristic expanded outgrowths with wavy edges which performed the functions of structures facilitating the capture of pollen grains. As a result of the present study it was found that the structures affecting the attractiveness of the

  15. Elements of the Chicxulub Impact Structure as revealed in SRTM and surface GPS topographic data (United States)

    Kobrick, M.; Kinsland, G. L.; Sanchez, G.; Cardador, M. H.


    Pope et al have utilized elevations from the Petroleos Mexicanos (PEMEX) gravity data files to show that the main component of the surface expression of the Chicxu-lub Impact Structure is a roughly semi-circular, low-relief depression about 90 km in diameter. They also identified other topographic features and the elements of the buried impact which possibly led to the development of these features. Kinsland et al presented a connection between these topographic anomalies, small gravity anomalies and buried structure of the impact. Shaded relief images from recently acquired SRTM elevation data clearly show the circular depression of the crater and the moat/cenote ring. In addition we can readily identify Inner trough 1, Inner trough 2 and Outer trough as defined by Pope et al. The agreement between the topographic maps of Pope et al, Kinsland et al and SRTM data are remarkable considering that the distribution and types of data in the sets are so different. We also have ground topographic data collected with a special "autonomous differ-ential GPS" system during summer 2002. Profiles from these data generally agree with both the gravity data based topographic maps and profiles extracted from the SRTM data. Preliminary analyses of our new data, SRTM and GPS, have uncovered features not previously recognized: 1) as shown by the GPS data the moat/cenote ring consists of two distinct depressions separated by about 10 km...perhaps separate ring faults, 2) in the SRTM data over the southern part of the crater and on southward for perhaps 20 km beyond the moat/ cenote ring there exists a pattern, as yet unexplained, of roughly concentric topographic features whose center lies at about 21deg 40min N and 89deg 25min W, about 50km NNE of the moat/cenote ring center. The corroboration and better definition of the previously recognized topographic features yielded by the two new forms of data strengthens the cases for these fea-tures and for their relevance to the underlying

  16. Advancements in the behavioral modeling of fuel elements and related structures

    Energy Technology Data Exchange (ETDEWEB)

    Billone, M.C.; Montgomery, R.O.; Rashid, Y.R.; Head, J.L. (Argonne National Lab., IL (USA); ANATECH Research Corp., San Diego, CA (USA); Royal Naval Coll., Greenwich (UK))


    An important aspect of the design and analysis of nuclear reactors is the ability to predict the behavior of fuel elements in the adverse environment of a reactor system. By understanding the thermomechanical behavior of the different materials which constitute a nuclear fuel element, analysis and predictions can be made regarding the integrity and reliability of fuel element designs. The SMiRT conference series, through the division on fuel elements and the post-conference seminars on fuel element modeling, provided technical forums for the international participation in the exchange of knowledge concerning the thermomechanical modeling of fuel elements. This paper discusses the technical advances in the behavioral modeling of fuel elements presented at the SMiRT conference series since its inception in 1971. Progress in the areas of material properties and constitutive relationships, modeling methodologies, and integral modeling approaches was reviewed and is summarized in light of their impact on the thermomechanical modeling of nuclear fuel elements. 34 refs., 5 tabs.

  17. Dynamic delamination of aeronautic structural composites by using cohesive finite elements


    Ilyas, Muhammad; Lachaud, Frédéric; Espinosa, Christine; Salaün, Michel


    Cohesive finite elements are used to model impact induced delamination prediction of T800/21M unidirectional laminated composite. DCB, ELS and MMB tests are used to identify cohesive element parameters. Results from experiments and numerical prediction of impact induced delamination by commercially available code LS-DYNA are compared.

  18. Influence of post material and length on endodontically treated incisors: an in vitro and finite element study. (United States)

    Chuang, Shu-Fen; Yaman, Peter; Herrero, Alberto; Dennison, Joseph B; Chang, Chih-Han


    Cast posts require sufficient length for prosthesis retention and root strength. For prefabricated metal and fiber posts, the effects of different post lengths on the strength and internal stress of the surrounding root need evaluation. The purpose of this study was to examine, using both experimental and finite element (FE) approaches, the influence of post material and length on the mechanical response of endodontically treated teeth. Sixty extracted incisors were endodontically treated and then restored with 1 of 3 prefabricated posts: stainless steel (SS), carbon fiber (CF), and glass fiber (GF), with intraradicular lengths of either 5 or 10 mm (n=10). After composite resin core and crown restorations, these teeth were thermal cycled and then loaded to fracture in an oblique direction. Statistical analysis was performed for the effects of post material and length on failure loads using 2-way ANOVA (α=.05). In addition, corresponding FE models of an incisor restored with a post were developed to examine mechanical responses. The simulated tooth was loaded with a 100-N oblique force to analyze the stress in the root dentin. The SS/5 mm and all fiber post groups presented no statistical differences, with mean (SD) fracture loads of 1247 to 1339 (53 to 121) N. The SS/10 mm group exhibited a lower fracture load, 973 (115) N, and a higher incidence of unfavorable root fracture (P<.05). The FE analysis showed high stress around the apical end of the long SS post, while stress was concentrated around the crown margins in the fiber post groups. Both long and short fiber posts provided root fracture resistance comparable to that of SS posts. For metal posts, extending the post length does not effectively prevent root fracture in restored teeth. Copyright © 2010 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

  19. Production of Curved Precast Concrete Elements for Shell Structures and Free-form Architecture using the Flexible Mould Method

    NARCIS (Netherlands)

    Schipper, H.R.; Grünewald, S.; Eigenraam, P.; Raghunath, P.; Kok, M.A.D.


    Free-form buildings tend to be expensive. By optimizing the production process, economical and well-performing precast concrete structures can be manufactured. In this paper, a method is presented that allows producing highly accurate double curved-elements without the need for milling two expensive

  20. In vitro digestibility and changes in physicochemical and structural properties of common buckwheat starch affected by high hydrostatic pressure. (United States)

    Liu, Hang; Wang, Lijing; Cao, Rong; Fan, Huanhuan; Wang, Min


    High hydrostatic pressure (HHP), a non-thermal processing technology, was applied at 120, 240, 360, 480, and 600MPa to assess its effect on the in vitro digestibility, physicochemical, and structural properties of common buckwheat starch (CBS). HHP treatment resulted in CBS granules with more rough surfaces. With the increasing pressure level, amylose content, pasting temperature, and thermal stability substantially increased and relative crystallinity, hardness, swelling power, and viscosity decreased. At 120-480MPa, HHP did not affect the 'A'-type crystalline pattern of CBS. However, at 600MPa, HHP contributed to a similar 'B'-type pattern. Compared with native starch, HHP-modified CBS samples had lower in vitro hydrolysis, reduced content of rapidly digestible starch, and increased levels of slowly digestible starch and resistant starch. These results revealed that the in vitro digestibility, physicochemical, and structural properties of CBS are effectively modified by HHP. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Planing of land use of structural elements of ecological network at local level

    Directory of Open Access Journals (Sweden)

    Tretiak V.


    Full Text Available and Management projecting of structural elements of land use of the ecological network on the territory of the village council begins with ecological and landscape micro zoning of the territory of village council, held during the preparatory work for the drafting of land and are finished by the formation of environmentally homogeneous regions, to which the system components of ecological network are tied, as well as environmental measures in the form of local environmental restrictions (encumbrances in land usage and other natural resources. Additionally organization and territorial measures are projected that increase the ecological sustainability of the area: key, binders, buffer areas and renewable ecological network. The regional scheme of ecological network is intended for usage while projecting of creation of new territories that fall under special protection, for defining the tasks as for changing the category of land in the land use planning documents, for development of specifications regarding the reproduction of natural systems on conservation ready lands withdrawn from agricultural use, for accounting the problems of formation the areas of ecological network in forest management and land management projects, while development of the projects of areas organization of natural - reserve fund, in the definition of wetlands of international importance, in determining the habitats of various plants and animals of various categories of protection in accordance with international conventions and national laws - regulations, in planning targeted actions in the conservation of landscape and biological diversity. The main stages of designing local ecological network are: • inventory and identification of rights for land and other natural resources, drawing created territories and objects of natural reserve fund and other areas of natural systems on the planning and cartographic materials, which are under special protection; • rationale of

  2. Impact of molecular and crystalline structures on in vitro digestibility of waxy rice starches. (United States)

    You, Su-Yeon; Lim, Seung-Taik; Lee, Ju Hun; Chung, Hyun-Jung


    The in vitro digestibility, molecular structure and crystalline structure of waxy rice starches isolated from six Korean cultivars (Shinsun, Dongjin, Baekok, Whasun, Chungbaek, and Bosuk) were investigated. The molecular weight (M(w)) of waxy rice starches ranged from 1.1 × 10(8)g/mol to 2.2 × 10(8)g/mol. Chungbaek waxy rice starch had the highest average chain length (24.3) and proportion (20.7%) of long branch chains (DP ≥ 37), and the lowest proportion (19.0%) of short branch chains (DP 6-12) among the tested six waxy rice starches. The relative crystallinity and intensity ratio of 1047/1022 ranged from 38.9% to 41.1% and from 0.691 to 0.707, respectively. Chungbaek had the highest gelatinization temperature and enthalpy. Chungbaek had the highest pasting temperature (70.7 °C), setback (324 cP) and final viscosity (943 cP), whereas Baekok showed the highest peak viscosity (1576 cP) and breakdown (1031 cP). Chungbaek had lower rapidly digestible starch (RDS) content and expected glycemic index (eGI), and higher resistant starch (RS) content, whereas Whasun exhibited higher RDS content and eGI. The slowly digestible starch (SDS) content of Shinsun (38.3%) and Bokok (32.0%) was significantly higher than that of other cultivars (11.3-22.0%). Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. In vitro induction of Entamoeba histolytica cyst-like structures from trophozoites.

    Directory of Open Access Journals (Sweden)

    Hugo Aguilar-Díaz

    Full Text Available Inhibition of encystment can be conceived as a potentially useful mechanism to block the transmission of Entamoeba histolytica under natural conditions. Unfortunately, amoeba encystment has not been achieved in vitro and drugs inhibiting the formation of cysts are not available. Luminal conditions inducing encystment in vivo are also unknown, but cellular stress such as exposure to reactive oxygen species from immune cells or intestinal microbiota could be involved. A role for certain divalent cations as cofactors of enzymes involved in excystment has also been described. In this study, we show that trophozoite cultures, treated with hydrogen peroxide in the presence of trace amounts of several cations, transform into small-sized spherical and refringent structures that exhibit resistance to different detergents. Ultrastructural analysis under scanning and transmission electron microscopy revealed multinucleated structures (some with four nuclei with smooth, thick membranes and multiple vacuoles. Staining with calcofluor white, as well as an ELISA binding assay using wheat germ agglutinin, demonstrated the presence of polymers of N-acetylglucosamine (chitin, which is the primary component of the natural cyst walls. Over-expression of glucosamine 6-phosphate isomerase, likely to be the rate-limiting enzyme in the chitin synthesis pathway, was also confirmed by RT-PCR. These results suggest that E. histolytica trophozoites activated encystment pathways when exposed to our treatment.

  4. Turbulent Flow Structure Inside a Canopy with Complex Multi-Scale Elements (United States)

    Bai, Kunlun; Katz, Joseph; Meneveau, Charles


    Particle image velocimetry laboratory measurements are carried out to study mean flow distributions and turbulent statistics inside a canopy with complex geometry and multiple scales consisting of fractal, tree-like objects. Matching the optical refractive indices of the tree elements with those of the working fluid provides unobstructed optical paths for both illuminations and image acquisition. As a result, the flow fields between tree branches can be resolved in great detail, without optical interference. Statistical distributions of mean velocity, turbulence stresses, and components of dispersive fluxes are documented and discussed. The results show that the trees leave their signatures in the flow by imprinting wake structures with shapes similar to the trees. The velocities in both wake and non-wake regions significantly deviate from the spatially-averaged values. These local deviations result in strong dispersive fluxes, which are important to account for in canopy-flow modelling. In fact, we find that the streamwise normal dispersive flux inside the canopy has a larger magnitude (by up to four times) than the corresponding Reynolds normal stress. Turbulent transport in horizontal planes is studied in the framework of the eddy viscosity model. Scatter plots comparing the Reynolds shear stress and mean velocity gradient are indicative of a linear trend, from which one can calculate the eddy viscosity and mixing length. Similar to earlier results from the wake of a single tree, here we find that inside the canopy the mean mixing length decreases with increasing elevation. This trend cannot be scaled based on a single length scale, but can be described well by a model, which considers the coexistence of multi-scale branches. This agreement indicates that the multi-scale information and the clustering properties of the fractal objects should be taken into consideration in flows inside multi-scale canopies.

  5. Visual-emotional elements of folk dance in the structure of pupils' writing

    Directory of Open Access Journals (Sweden)

    Jovanović Aleksandar M.


    Full Text Available Familiarizing the pupils with the concept of folk dance. Folk dance as a part of folk lore. The elements of folk dance (music, song, costume, coreography. Observing integral elements. Syncretism. Describing observed and experienced phenomena. Description of dynamic artistic image. Description of folk dance introduces pupils for observation and appreciation. First to be described are easily observable, dominant elements, to be followed by other details which can be observed by pupils and which are conditional on their psychical and emotional abilities.

  6. Influence of test parameters on in vitro fracture resistance of post-endodontic restorations: a structured review.

    NARCIS (Netherlands)

    Naumann, M.; Metzdorf, G.; Fokkinga, W.A.; Watzke, R.; Sterzenbach, G.; Bayne, S.; Rosentritt, M.


    A structured literature review aimed to elucidate test parameters for in vitro testing of post-endodontic restorations. The literature was digitally searched using MEDLINE, EMBASE, MedPilot and an additional hand search was performed. Two independent researchers assessed the articles in relation to

  7. Synthesis, crystal structure, and in vitro and in silico molecular docking of novel acyl thiourea derivatives (United States)

    Haribabu, Jebiti; Subhashree, Govindarajulu Rangabashyam; Saranya, Sivaraj; Gomathi, Kannayiram; Karvembu, Ramasamy; Gayathri, Dasararaju


    In the present study, a series of six biologically active substituted acyl thiourea compounds (1-6) has been synthesized from cyclohexanecarbonyl isothiocyanate and various primary amines (2-methyl aniline, aniline, 4-methoxy aniline, 4-ethoxy aniline, benzyl amine and 2-methoxy aniline). The synthesized compounds were characterized by elemental analyses, UV-Visible, FT-IR, 1H & 13C NMR and mass spectroscopic techniques. Three dimensional molecular structure of two compounds (1 and 5) was determined by single crystal X-ray crystallography. All the synthesized compounds show good anti-oxidant and anti-haemolytic activities. In silico molecular docking studies were performed to screen against DprE1 and HSP90 enzymes targeting tuberculosis and cancer respectively.

  8. The KnowRISK project - Know your city, Reduce seISmic risK through non-structural elements (United States)

    Sousa Oliveria, Carlos; Amaral Ferreira, Mónica; Lopez, Mário; Sousa Silva, Delta; Musacchio, Gemma; Rupakhety, Rajesh; Falsaperla, Susanna; Meroni, Fabrizio; Langer, Horst


    Historically, there is a tendency to focus on seismic structural performance of buildings, neglecting the potential for damage of non-structural elements. In particular, non-structural elements of buildings are their architectural parts (i.e. partitions, ceilings, cladding), electrical and mechanical components (i.e., distribution panels, piping, plumbing), and contents (e.g., furniture, bookcases, computers and desktop equipment). Damage of these elements often contributes significantly to earthquake impacts. In the 1999 Izmit Earthquake, Turkey, 50% of the injuries and 3% of human losses were caused by non-structural failures. In the 2010-2011 Christchurch Earthquakes (New Zealand), 40% of building damage was induced by non-structural malfunctions. Around 70%-85% of construction cost goes into these elements, and their damage can strongly influence the ability of communities to cope with and recover from earthquakes. The project Know your city, Reduce seISmic risK through non-structural elements (KnowRISK) aims at facilitating local communities' access to expert knowledge on non-structural seismic protection solutions. The project will study seismic scenarios critical for non-structural damage, produce a portfolio of non-structural protection measures and investigate the level of awareness in specific communities. We will implement risk communication strategies that will take into account the social and cultural background and a participatory approach to raise awareness in local communities. The paradox between the progress of scientific knowledge and the ongoing increase of losses from natural disasters worldwide is a well-identified gap in the UN Hyogo Framework for Action 2005-2015, in which one of the main priorities is the investment on "knowledge use, innovation and education to build a culture of safety and resilience". The KnowRISK is well aligned with these priorities and will contribute to participatory action aimed at: i) transferring expert knowledge

  9. Electronic structures of platinum group elements silicides calculated by a first-principle pseudopotential method using plane-wave basis

    Energy Technology Data Exchange (ETDEWEB)

    Imai, Y. [National Institute of Advanced Industrial Science and Technology, AIST Tsukuba Central 5, Higashi 1-1 Tsukuba, Ibaraki 305-8565 (Japan); Watanabe, A. [National Institute of Advanced Industrial Science and Technology, AIST Tsukuba Central 5, Higashi 1-1 Tsukuba, Ibaraki 305-8565 (Japan)


    The electronic structures of platinum group elements (Ru, Os, Rh, Ir, Pd, and Pt) silicides have been calculated. Ir{sub 3}Si{sub 5} is a semiconductor with the direct gap of 1.14 eV. Among monosilicides, RuSi and OsSi with the FeSi-type structure are semiconductors with the gap values of 0.21 and 0.41 eV but RhSi, IrSi, PdSi, and PtSi with the MnP-type structure are metals. No semiconducting compounds can be found in other platinum group elements silicides other than known Ru{sub 2}Si{sub 3}, Os{sub 2}Si{sub 3}, and OsSi{sub 2}.

  10. Mass transport processes in orange-fleshed sweet potatoes leading to structural changes during in vitro gastric digestion


    Mennah-Govela, YA; Bornhorst, GM


    © 2016 Elsevier Ltd During cooking, food undergoes structural modifications, which may impact its behavior during digestion. The objective of this study was to determine the macro- and micro-structural changes, moisture uptake, and acid uptake into sweet potatoes during simulated gastric digestion as influenced by cooking method. Sweet potatoes were cut and cooked (boiled, steamed, microwave steamed or fried), followed by in vitro gastric digestion (up to 240 min). Acidity, moisture content, ...

  11. Finite element modeling of reinforced concrete structures strengthened with FRP laminates : final report. (United States)


    Linear and non-linear finite element method models were developed for a reinforced concrete bridge that had been strengthened with fiber reinforced polymer composites. ANSYS and SAP2000 modeling software were used; however, most of the development ef...

  12. Finite element model validation of bridge based on structural health monitoring—Part I: Response surface-based finite element model updating

    Directory of Open Access Journals (Sweden)

    Zhouhong Zong


    Full Text Available In the engineering practice, merging statistical analysis into structural evaluation and assessment is a tendency in the future. As a combination of mathematical and statistical techniques, response surface (RS methodology has been successfully applied to design optimization, response prediction and model validation. With the aid of RS methodology, these two serial papers present a finite element (FE model updating and validation method for bridge structures based on structural health monitoring. The key issues to implement such a model updating are discussed in this paper, such as design of experiment, parameter screening, construction of high-order polynomial response surface model, optimization methods and precision inspection of RS model. The proposed procedure is illustrated by a prestressed concrete continuous rigid-frame bridge monitored under operational conditions. The results from the updated FE model have been compared with those obtained from online health monitoring system. The real application to a full-size bridge has demonstrated that the FE model updating process is efficient and convenient. The updated FE model can relatively reflect the actual condition of Xiabaishi Bridge in the design space of parameters and can be further applied to FE model validation and damage identification.

  13. Coupled Finite Element and Cellular Automata Methods for Analysis of Composite Structures in an Acoustic Domain (United States)


    core crushing, skin wrinkling , and general buckling . Debonding is the separation of the skin material from the core and delamination usually refers...or plate, for example, can be modeled with relative fidelity with just a few elements; while the analysis of air-flow over a golf ball would require...elements of a size comparable to the ball’s dimples, which could lead to an exorbitant computational cost for a domain on the order of three ball

  14. Effect of alkaline elements on the reactivity, strength and structural properties of blast furnace cokes


    A. Bhattacharyya; J. Schenk; G. Rantitsch; C. Thaler; H. Stocker


    The present study concerns itself on the adverse effects of alkaline elements like sodium and potassium on blast furnace cokes. To achieve a deeper insight on the effects of alkaline elements on coke reactivity and strength, industrial coke samples impregnated with different alkaline species in various amounts have been tested under standard conditions to find out their Coke Reactivity Index (CRI) and Coke Strength after Reaction (CSR) values. Scanning electron microscopy, petrographic and Ra...

  15. Effects of finite element formulation on optimal plate and shell structural topologies

    CSIR Research Space (South Africa)

    Long, CS


    Full Text Available . Strain energy was minimized subject to a volume constraint. Again, simple four noded quadrilateral elements with 5 DOFs per node were employed with selective reduced integration (SRI) to alleviate shear locking. There are of course numerous other... terms to overcome transverse shear locking. Since then SIMP-like material parametrizations have become very popular in this type of problem, see for example Pedersen [14], Jog [15] (who implement the MITC4 and MITC9 elements of Bathe and co...

  16. In vitro biological characterization of macroporous 3D Bonelike structures prepared through a 3D machining technique

    Energy Technology Data Exchange (ETDEWEB)

    Laranjeira, M.S.; Dias, A.G. [INEB - Instituto de Engenharia Biomedica, Divisao de Biomateriais, Universidade do Porto, Rua do Campo Alegre, 823, 4150-180 Porto (Portugal); Santos, J.D. [INEB - Instituto de Engenharia Biomedica, Divisao de Biomateriais, Universidade do Porto, Rua do Campo Alegre, 823, 4150-180 Porto (Portugal); Universidade do Porto, Faculdade de Engenharia, Departamento de Engenharia Metalurgica e Materiais, Rua Dr. Roberto Frias, 4200-465 Porto - Portugal (Portugal); Fernandes, M.H., E-mail: [Universidade do Porto, Faculdade de Medicina Dentaria, Laboratorio de Farmacologia e Biocompatibilidade Celular, Rua Dr. Manuel Pereira da Silva, 4200-392 Porto (Portugal)


    3D bioactive macroporous structures were prepared using a 3D machining technique. A virtual 3D structure model was created and a computer numerically controlled (CNC) milling device machined Bonelike samples. The resulting structures showed a reproducible macroporosity and interconnective structure. Macropores size after sintering was approximately 2000 {mu}m. In vitro testing using human bone marrow stroma showed that cells were able to adhere and proliferate on 3D structures surface and migrate into all macropore channels. In addition, these cells were able to differentiate, since mineralized globular structures associated with cell layer were identified. Results obtained showed that 3D structures of Bonelike successfully allow cell migration into all macropores, and allow human bone marrow stromal cells to proliferate and differentiate. This innovative technique may be considered as a step-forward preparation for 3D interconnective macroporous structures that allow bone ingrowth while maintaining mechanical integrity.

  17. The verification of a new approach to the experimental estimation of tensile forces in prestressed structural elements by method based on the magnetoelastic principle

    Directory of Open Access Journals (Sweden)

    Klier Tomáš


    Full Text Available There are a large number of civil engineering structures where the important structural elements are loaded by large tensile forces. In many practical cases, it is significant to know the current value of tensile force or prestressed stress in these elements for accurate assessment of the reliability of the whole structure. The brief principle and the basic validation results of the new approach to the experimental estimation of tensile forces or stress in prestressed structural elements of engineering structures by the method based on the magnetoelastic principle are described in the paper. The new approach was designed and developed especially for application on existing prestressed concrete structures.

  18. Investigation of wing structure layout of aerospace plane based on the finite element method

    National Research Council Canada - National Science Library

    Wang, Yu; Liu, Lei; Xing, Yu; Yang, Zhenbo


    .... Two kinds of aerospace plane wing structures are designed and parameterized for the delta wing with a strake, one of which is an equal percentage multi-web structure, and the other is a parallel multi-web structure...

  19. Long-acting genipin derivative protects retinal ganglion cells from oxidative stress models in vitro and in vivo through the Nrf2/antioxidant response element signaling pathway. (United States)

    Koriyama, Yoshiki; Chiba, Kenzo; Yamazaki, Matsumi; Suzuki, Hirokazu; Muramoto, Ken-ichiro; Kato, Satoru


    Previously, we reported that genipin, a herbal iridoid, had neuritogenic and neuroprotective actions on PC12 cells. Although nitric oxide (NO)-activated signalings were proposed to be neuritogenic, the neuroprotective action of genipin remains to be elucidated. From the standpoint of NO activation, we tested a possible protective mechanism through the nitrosative Kelch-like ECH-associated protein (Keap1)/NF-E2-related factor 2 (Nrf2)-antioxidant response element pathway in rat retinal ganglion cells (RGC-5 cells) in culture, and in vivo, against hydrogen peroxide and optic nerve injury (ONI), respectively, using a long-acting (1R)-isoPropyloxygenipin (IPRG001). IPRG001 induced NO generation and the expressions of antioxidative enzymes, such as heme oxygenase-1 (HO-1), in RGC-5 cells. The protective action of IPRG001 depended on HO-1 and NO induction. We found that S-nitrosylation of Keap1 by IPRG001 may contribute to translocation of Nrf2 to the nucleus and triggered transcriptional activation of antioxidative enzymes. Furthermore, apoptotic cells were increased and 4-hydroxy-2-nonenal was accumulated in rat retina following ONI. Pre-treatment with IPRG001 almost completely suppressed apoptosis and accumulation of 4-hydroxy-2-nonenal in RGCs following ONI accompanied by HO-1 induction. These data demonstrate for the first time that IPRG001 exerts neuroprotective action in RGCs in vitro and in vivo, through the Nrf2/antioxidant response element pathway by S-nitrosylation against oxidative stress. © 2010 The Authors. Journal Compilation © 2010 International Society for Neurochemistry.

  20. The Integration of Geotechnologies in the Evaluation of a Wine Cellar Structure through the Finite Element Method

    Directory of Open Access Journals (Sweden)

    Alberto Villarino


    Full Text Available This paper presents a multidisciplinary methodology to evaluate an underground wine cellar structure using non-invasive techniques. In particular, a historical subterranean wine cellar that presents a complex structure and whose physical properties are unknown is recorded and analyzed using geomatics and geophysics synergies. To this end, an approach that integrates terrestrial laser scanning and ground penetrating radar is used to properly define a finite element-based structural model, which is then used as a decision tool to plan architectural restoration actions. The combination of both techniques implies the registration of external and internal information that eases the construction of structural models. Structural simulation for both stresses and deformations through FEM allowed identifying critical structural elements under great stress or excessive deformations. In this investigation, the ultimate limit state of cracking was considered to determine allowable loads due to the brittle nature of the material. This allowed us to set limit values of loading on the cellar structure in order to minimize possible damage.

  1. Seismic assessment of reinforced concrete frame structures with a new flexibility based element (United States)

    Arede, Antonio Jose Coelho Dias

    As piroxenas sao um vasto grupo de silicatos minerais encontrados em muitas rochas igneas e metamorficas. Na sua forma mais simples, estes silicatos sao constituidas por cadeias de SiO3 ligando grupos tetrahedricos de SiO4. A formula quimica geral das piroxenas e M2M1T2O6, onde M2 se refere a catioes geralmente em uma coordenacao octaedrica distorcida (Mg2+, Fe2+, Mn2+, Li+, Ca2+, Na+), M1 refere-se a catioes numa coordenacao octaedrica regular (Al3+, Fe3+, Ti4+, Cr3+, V3+, Ti3+, Zr4+, Sc3+, Zn2+, Mg2+, Fe2+, Mn2+), e T a catioes em coordenacao tetrahedrica (Si4+, Al3+, Fe3+). As piroxenas com estrutura monoclinica sao designadas de clinopiroxenes. A estabilidade das clinopyroxenes num espectro de composicoes quimicas amplo, em conjugacao com a possibilidade de ajustar as suas propriedades fisicas e quimicas e a durabilidade quimica, tem gerado um interesse mundial devido a suas aplicacoes em ciencia e tecnologia de materiais. Este trabalho trata do desenvolvimento de vidros e de vitro-cerâmicos baseadas de clinopiroxenas para aplicacoes funcionais. O estudo teve objectivos cientificos e tecnologicos; nomeadamente, adquirir conhecimentos fundamentais sobre a formacao de fases cristalinas e solucoes solidas em determinados sistemas vitro-cerâmicos, e avaliar a viabilidade de aplicacao dos novos materiais em diferentes areas tecnologicas, com especial enfase sobre a selagem em celulas de combustivel de oxido solido (SOFC). Com este intuito, prepararam-se varios vidros e materiais vitro-cerâmicos ao longo das juntas Enstatite (MgSiO3) - diopsidio (CaMgSi2O6) e diopsidio (CaMgSi2O6) - Ca - Tschermak (CaAlSi2O6), os quais foram caracterizados atraves de um vasto leque de tecnicas. Todos os vidros foram preparados por fusao-arrefecimento enquanto os vitro-cerâmicos foram obtidos quer por sinterizacao e cristalizacao de fritas, quer por nucleacao e cristalizacao de vidros monoliticos. Estudaram-se ainda os efeitos de varias substituicoes ionicas em composicoes de

  2. Secondary Structure and Subunit Composition of Soy Protein In Vitro Digested by Pepsin and Its Relation with Digestibility

    Directory of Open Access Journals (Sweden)

    Yong Yang


    Full Text Available In the present study, in vitro digestibility and structure of soybean protein isolates (SPIs prepared from five soybean varieties were investigated in simulated gastric fluid (SGF, using FT-IR microspectroscopy and SDS-PAGE. The result indicated that β-conformations were prone to be hydrolyzed by pepsin preferentially and transformed to unordered structure during in vitro digestion, followed by the digestion of α-helix and unordered structure. A negative linear correlation coefficient was found between the β-conformation contents of five SPIs and their in vitro digestibility values. The intensities of the protein bands corresponding to 7S and 11S fractions were decreased and many peptide bands appeared at 11~15 kDa during enzymatic hydrolysis. β-conglycinin was poorly hydrolyzed with pepsin, especially the β-7S subunit. On the other hand, basic polypeptides of glycinin degraded slower than acidic polypeptides and represented a large proportion of the residual protein after digestion. 11S-A3 of all SPIs disappeared after 1 h digestion. Moreover, a significant negative linear correlation coefficient (r=-0.89 was found between the β-7S contents of five SPIs and their in vitro digestibility values. These results are useful for further studies of the functional properties and bioactive properties of these varieties and laid theoretical foundations for the development of the specific functional soy protein isolate.

  3. Design of Software for Design of Finite Element for Structural Analysis. Ph.D. Thesis - Stuttgart Univ., 22 Nov. 1983 (United States)

    Helfrich, Reinhard


    The concepts of software engineering which allow a user of the finite element method to describe a model, to collect and to check the model data in a data base as well as to form the matrices required for a finite element calculation are examined. Next the components of the model description are conceived including the mesh tree, the topology, the configuration, the kinematic boundary conditions, the data for each element, and the loads. The possibilities for description and review of the data are considered. The concept of the segments for the modularization of the programs follows the components of the model description. The significance of the mesh tree as a globular guiding structure will be understood in view of the principle of the unity of the model, the mesh tree, and the data base. The user-friendly aspects of the software system will be summarized: the principle of language communication, the data generators, error processing, and data security.

  4. Applications of condensed matter understanding to medical tissues and disease progression: Elemental analysis and structural integrity of tissue scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, D.A., E-mail: [Centre for Nuclear and Radiation Physics, Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Farquharson, M.J. [Department of Radiography, School of Community and Health Sciences, City University, London (United Kingdom); Gundogdu, O. [Centre for Nuclear and Radiation Physics, Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Al-Ebraheem, Alia [Department of Radiography, School of Community and Health Sciences, City University, London (United Kingdom); Che Ismail, Elna [Centre for Nuclear and Radiation Physics, Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Kaabar, W., E-mail: [Centre for Nuclear and Radiation Physics, Department of Physics, University of Surrey, Guildford GU2 7XH (United Kingdom); Bunk, O. [Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Pfeiffer, F. [Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Falkenberg, G. [Hamburger Synchrotronstrahlungslabor HASYLAB at Deutsches Elektronensynchrotron DESY, Notkestr. 85, D-22603 Hamburg (Germany); Bailey, M. [Surrey Ion Beam Centre, Advanced Technology Institute, University of Surrey, Guildford GU2 7XH (United Kingdom)


    The investigations reported herein link tissue structure and elemental presence with issues of environmental health and disease, exemplified by uptake and storage of potentially toxic elements in the body, the osteoarthritic condition and malignancy in the breast and other soft tissues. Focus is placed on application of state-of-the-art ionizing radiation techniques, including, micro-synchrotron X-ray fluorescence (mu-SXRF) and particle-induced X-ray emission/Rutherford backscattering mapping (mu-PIXE/RBS), coherent small-angle X-ray scattering (cSAXS) and X-ray phase-contrast imaging, providing information on elemental make-up, the large-scale organisation of collagen and anatomical features of moderate and low atomic number media. For the particular situations under investigation, use of such facilities is allowing information to be obtained at an unprecedented level of detail, yielding new understanding of the affected tissues and the progression of disease.

  5. The effect of carbohydrate moiety structure on the immunoregulatory activity of lactoferrin in vitro. (United States)

    Zimecki, Michał; Artym, Jolanta; Kocięba, Maja; Duk, Maria; Kruzel, Marian L


    The aim of this study was to evaluate the immunoregulatory effects of recombinant human lactoferrin (rhLF) in two in vitro models: (1) the secondary humoral immune response to sheep erythrocytes (SRBC); and (2) the mixed lymphocyte reaction (MLR). We compared the non-sialylated glycoform of rhLF as expressed by glycoengineered Pichia pastoris with one that was further chemically sialylated. In an earlier study, we showed that sialylated rhLF could reverse methotrexate-induced suppression of the secondary immune response of mouse splenocytes to SRBC, and that the phenomenon is dependent on the interaction of lactoferrin (LF) with sialoadhesin (CD169). We found that the immunorestorative activity of sialylated rhLF is also dependent on its interaction with the CD22 antigen, a member of the immunoglobulin superfamily that is expressed by B lymphocytes. We also demonstrated that only sialylated rhLF was able to inhibit the MLR reaction. MLR was inhibited by bovine lactoferrin (bLF), a glycoform that has a more complex glycan structure. Desialylated bLF and lactoferricin, a bLF-derived peptide devoid of carbohydrates, did not express such inhibitory activity. We showed that the interaction of LF with sialic acid receptors is essential for at least some of the immunoregulatory activity of this glycoprotein.

  6. Immiscible silicate liquids at high pressure: the influence of melt structure on elemental partitioning

    Energy Technology Data Exchange (ETDEWEB)

    Vicenzi, E. [Princeton Materials Laboratory, Princeton, NJ (United States); Green, T.H. [Macquarie Univ., North Ryde, NSW (Australia); Sie, S.H. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), North Ryde, NSW (Australia). Div. of Exploration Geoscience


    Micro-PIXE analyses have been applied to study partitioning of trace elements between immiscible silicate melts stabilised at 0.5 and 1.0 GPa over a temperature range of 1160-1240 deg C in the system SiO{sub 2}-FeO-Al{sub 2}0{sub 3}-K{sub 2}0 (+P{sub 2}0{sub 5}). The system was doped with a suite of trace elements of geochemical interest: Rb, Ba, Pb, Sr, La, Ce, Sm, Ho, Y, Lu, Th, U, Zr, Hf, Nb and Ta at approximately 200 ppm level for all elements except for the REE`s, Ba and Ta (600-1200 ppm). Trace element partitioning was found to be a complex function of cation field strength (charge/radius{sup 2}). Although field strength is important in determining the nature and degree of partitioning, the authors emphasised that it is only one component of the underlying mechanism for the way in which elements distribute themselves between two silicate liquids. 8 refs., 2 figs.

  7. Structures of pulmonary surfactant films adsorbed to an air-liquid interface in vitro. (United States)

    Bachofen, H; Gerber, U; Gehr, P; Amrein, M; Schürch, S


    Phospholipid films can be preserved in vitro when adsorbed to a solidifiable hypophase. Suspensions of natural surfactant, lipid extract surfactants, and artificial surfactants were added to a sodium alginate solution and filled into a captive bubble surfactometer (CBS). Surfactant film was formed by adsorption to the bubble of the CBS for functional tests. There were no discernible differences in adsorption, film compressibility or minimal surface tension on quasi-static or dynamic compression for films formed in the presence or absence of alginate in the subphase of the bubble. The hypophase-film complex was solidified by adding calcium ions to the suspension with the alginate. The preparations were stained with osmium tetroxide and uranyl acetate for transmission electron microscopy. The most noteworthy findings are: (1) Surfactants do adsorb to the surface of the bubble and form osmiophilic lining layers. Pure DPPC films could not be visualized. (2) A distinct structure of a particular surfactant film depends on the composition and the concentration of surfactant in the bulk phase, and on whether or not the films are compressed after their formation. The films appear heterogeneous, and frequent vesicular and multi-lamellar film segments are seen associated with the interfacial films. These features are seen already upon film formation by adsorption, but multi-lamellar segments are more frequent after film compression. (3) The rate of film formation, its compressibility, and the minimum surface tension achieved on film compression appear to be related to the film structure formed on adsorption, which in turn is related to the concentration of the surfactant suspension from which the film is formed. The osmiophilic surface associated surfactant material seen is likely important for the surface properties and the mechanical stability of the surfactant film at the air-fluid interface.

  8. Silica/potassium ferrite nanocomposite: Structural, morphological, magnetic, thermal and in vitro cytotoxicity analysis

    Energy Technology Data Exchange (ETDEWEB)

    Khanna, Lavanya, E-mail:; Verma, N.K.


    Highlights: • Silica coating on potassium ferrite nanoparticles is reported. • Their structural, morphological, thermal behaviour is studied and compared. • Both bare and coated nanoparticles are superparamagnetic and biocompatible. -- Abstract: The coating of silica on potassium ferrite (KFeO{sub 2}) nanoparticles has been reported in the present study. The X-ray diffraction pattern revealed the formation of orthorhombic structure of bare potassium ferrite nanoparticles, which was also retained after the silica coating, along with a broad band near 2θ ∼ 20–25° pertaining to the presence of amorphous silica. The size of bare and coated potassium ferrite nanoparticles was found to be 4–8 nm and 10–22 nm, respectively, as observed from transmission electron microscope. The presence of silica was also revealed by the Fourier transform infrared spectrum and high resolution transmission electron microscope. In vibrating sample magnetometer analysis, both bare as well as coated potassium ferrite nanoparticles exhibited superparamagnetic behaviour with magnetic saturation values, 49.01 and 21.17 emu/g, respectively. Dose-dependent cellular toxicity was observed in the in vitro MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, a tetrazole) – assay study on Jurkat cells, where both bare as well as silica coated nanoparticles exhibited non-toxicity below 250 μg/ml. An augmentation of cell viability was observed in case of silica coated potassium ferrite nanoparticles. The nanosize, superparamagnetic behaviour and enhanced cell viability make silica coated potassium ferrite nanoparticles a potential claimant for biomedical applications.

  9. Ultrasonic Structural Health Monitoring to Assess the Integrity of Spinal Growing Rods In Vitro. (United States)

    Oetgen, Matthew E; Goodley, Addison; Yoo, Byungseok; Pines, Darryll J; Hsieh, Adam H


    Rod fracture is a common complication of growing rods and can result in loss of correction, patient discomfort, and unplanned revision surgery. The ability to quantitate rod integrity at each lengthening would be advantageous to avoid this complication. We investigate the feasibility of applying structural health monitoring to evaluate the integrity of growing rods in vitro. Single-rod titanium 4.5-mm growing rod constructs (n = 9), one screw proximally and one distally connected by in-line connectors, were assembled with pedicle screws fixed in polyethylene blocks. Proximal and distal ends were loaded and constructs subjected to cyclic axial compression (0-100 N at 1 Hz), with incrementally increasing maximum compressive loads of 10 N every 9k cycles until failure. Four piezoceramic transducers (PZTs) were mounted along the length the constructs to interrogate the integrity of the rods with an ultrasonic, guided lamb wave approach. Every 9k cycles, an 80 V excitatory voltage was applied to a PZT to generate high-frequency vibrations, which, after propagating through the construct, was detected by the remaining PZTs. Amplitude differences between pre- and postload waveform signals were calculated until rod failure. Average construct lifetime was 88,991 ± 13,398 cycles. All constructs failed due to rod fracture within 21 mm (mean = 15 ± 4.5 mm) of a screw or connector. Amplitude differences between pre- and postload increased in a stepwise fashion as constructs were cycled. Compared to baseline, we found a 1.8 ± 0.6-fold increase in amplitude 18k cycles before failure, a 2.2 ± 1.0-fold increase in amplitude 9k cycles before failure, and a 2.75 ± 1.5-fold increase in amplitude immediately before rod fracture. We describe a potential method for assessing the structural integrity of growing rods using ultrasonic structural health monitoring. These preliminary data demonstrate the ability of periodic rod assessment to detect structural changes in cycled growing

  10. [Effect of astragalus membranaceus on the proliferation, osteogenic capacity and structure of periodontal ligament cells in vitro]. (United States)

    Zhang, Chao-liang; Kong, Xiang-li; Chen, Si-xiu; Li, Xiao-yu


    To investigate the effect of Astragalus membranaceus (APS) on the proliferation, osteogenic capacity and structure of periodontal ligament cells (PDLCs) in vitro. PDLCs were cultured in vitro with APS of 0.08, 0.1, 0.2, 0.4 mg x mL(-1). Methyl thiazolyl tetrazolium (MTr), alkaline phosphatase (ALP) and cell structure were detected to determine the proliferation and differentiation of PDLCs proliferation and differentiation. When the APS was 0.2 mg x mL(-1), the absorbance of MTT and ALP exhibit significantly increased as compared to the control (P structure. APS with proper concentration in short-term culture may promote the proliferation and differentiation of PDLCs.

  11. In vitro germination and structure of hard seed testa of natural ...

    African Journals Online (AJOL)

    Scarified and non-scarified seeds of natural tetraploid Trifolium pratense L. were germinated on in vitro and ex vitro germination media. The medium producing the best outcome was determined and germination media were compared. Additionally, testa of normal and hard seeds were examined. The media producing the ...

  12. In vitro germination and structure of hard seed testa of natural ...

    African Journals Online (AJOL)



    Mar 3, 2008 ... Scarified and non-scarified seeds of natural tetraploid Trifolium pratense L. were germinated on in vitro and ex vitro germination media. The medium producing the best outcome was determined and germination media were compared. Additionally, testa of normal and hard seeds were examined. The.

  13. Rigid Finite Element Method in Analysis of Dynamics of Offshore Structures

    CERN Document Server

    Wittbrodt, Edmund; Maczyński, Andrzej; Wojciech, Stanisław


    This book describes new methods developed for modelling dynamics of machines commonly used in the offshore industry. These methods are based both on the rigid finite element method, used for the description of link deformations, and on homogeneous transformations and joint coordinates, which is applied to the modelling of multibody system dynamics. In this monograph, the bases of the rigid finite element method  and homogeneous transformations are introduced. Selected models for modelling dynamics of offshore devices are then verified both by using commercial software, based on the finite element method, as well as by using additional methods. Examples of mathematical models of offshore machines, such as a gantry crane for Blowout-Preventer (BOP) valve block transportation, a pedestal crane with shock absorber, and pipe laying machinery are presented. Selected problems of control in offshore machinery as well as dynamic optimization in device control are also discussed. Additionally, numerical simulations of...

  14. In Vitro Selection of a Single-Stranded DNA Molecular Recognition Element against the Pesticide Fipronil and Sensitive Detection in River Water

    Directory of Open Access Journals (Sweden)

    Ka L. Hong


    Full Text Available Fipronil is a commonly used insecticide that has been shown to have environmental and human health risks. The current standard methods of detection for fipronil and its metabolites, such as GC-MS, are time consuming and labor intensive. In this study, a variant of systematic evolution of ligands by exponential enrichment (SELEX, was utilized to identify the first single-stranded DNA (ssDNA molecular recognition element (MRE that binds to fipronil with high affinity (Kd = 48 ± 8 nM. The selected MRE displayed low cross binding activity on various environmentally relevant, structurally unrelated herbicides and pesticides, in addition to broad-spectrum binding activity on major metabolites of fipronil and a structurally similar pesticide in prepared river samples. Additionally, a proof-of-principle fluorescent detection assay was developed by using the selected ssDNA MRE as a signal-reporting element, with a limit of detection of 105 nM in a prepared river water sample.

  15. Evaluation of the kinematic structure of indicators key elements of sports equipment exercise by postural orientation movements

    Directory of Open Access Journals (Sweden)

    Litvinenko Y.V.


    Full Text Available Purpose : Examine the kinematic structure of indicators key elements of sports equipment exercise (difficult to coordinate. The method of postural orientation movements. Material : The study involved acrobats jumpers on the path of high qualification (n = 7. The method used video - computer recording the movements of the athlete. Results : Identified nodal elements of sports equipment double back somersault tuck. Exercise performed after rondat and double back flip and stretch after rondat - flick (coup ago. In the preparatory phase of motor actions acrobatic exercises isolated and studied central element of sports equipment - starting posture of the body; in the phase of the main motor action - animation poses of the body; in the final phase - the final body posture (stable landing. Conclusions : The method of video - computer registration allowed to perform a biomechanical analysis and evaluation of key elements of sports equipment double back somersault tuck and a double back flip and stretch. Also gain new knowledge about the mechanism of the phase structure of movements when performing double somersaults.


    Directory of Open Access Journals (Sweden)

    O. M. Bondarev


    Full Text Available Purpose. The purpose of article is to develop the measures of hardness indices improvement of the supporting structures of motor cars of the electric trains ED9M. Methodology. In order to achieve the above stated aims the following measures had to be done: to develop a finite element model of the supporting structures of the motor bogie of the electric train ED9M, determine parameters of the developed model; perform the calculations to determine the stress-strain state during loads corresponding to different operating conditions with the search of geometric parameters reducing the highest stress levels. Findings. The obtained results of calculations (fields of stress distribution and strains in the elements of the motor bogie frame from the viewpoint of the strength and stiffness discovered the best geometric parameters of the bearings in the central suspension beams of the electric trains ED9M in the places of load transmission from the car body to the bogie frame. Originality. Based on the developed finite element models and the theoretical and experimental researches the scientifically grounded modernization measures of the construction elements of the central suspension beams for motor bogies of the electric trains ED9M were developed. Practical value. It was developed an engineering solution concerning the measures to improve the strength and stiffness characteristics of the central suspension beams for the motor cars of the electric trains ED9M. It was given to the Ukrzaliznytsya’s professionals to implement them during repairs.

  17. Identification and detection of a novel human endogenous retrovirus-related gene, and structural characterization of its related elements

    Directory of Open Access Journals (Sweden)

    Qiaoyi Liang


    Full Text Available Up-regulation of human endogenous retroviruses (HERVs is associated with many diseases, including cancer. In this study, an H family HERV (HERV-H-related gene was identified and characterized. Its spliced transcript lacks protein-coding capacity and may belong to the emerging class of noncoding RNAs (ncRNAs. The 1.3-kb RNA consisting of four exons is transcribed from an Alu element upstream of a 5.0-kb structurally incomplete HERV-H element. RT-PCR and quantitative RT-PCR results indicated that expression of this HERV-related transcript was negatively associated with colon, stomach, and kidney cancers. Its expression was induced upon treatment with DNA methylation and histone deacetylation inhibitors. A BLAT search using long terminal repeats (LTRs identified 50 other LTR homogenous HERV-H elements. Further analysis of these elements revealed that all are structurally incomplete and only five exert transcriptional activity. The results presented here recommend further investigation into a potentially functional HERV-H-related ncRNA.

  18. Copper (II) complexes possessing alkyl-substituted polypyridyl ligands: Structural characterization and in vitro antitumor activity. (United States)

    Angel, Noah R; Khatib, Raneen M; Jenkins, Julia; Smith, Michelle; Rubalcava, Justin M; Le, Brian Khoa; Lussier, Daniel; Chen, Zhuo Georgia; Tham, Fook S; Wilson, Emma H; Eichler, Jack F


    In an effort to find alternatives to the antitumor drug cisplatin, a series of copper (II) complexes possessing alkyl-substituted polypyridyl ligands have been synthesized. Eight new complexes are reported herein: μ-dichloro-bis{2,9-di-sec-butyl-1,10-phenanthrolinechlorocopper(II)} {[((di-sec-butyl)phen)ClCu(μ-Cl)2CuCl((di-sec-butyl)phen)]}(1), 2-sec-butyl-1,10-phenanthrolinedichlorocopper(II) {([mono-sec-butyl)phen) CuCl2} (2), 2,9-di-n-butyl-1,10-phenanthrolinedichlorocopper(II) {[(di-n-butyl)phen) CuCl2}(3), 2-n-butyl-1,10-phenanthrolinedichlorocopper(II) {[(mono-n-butyl)phen) CuCl2} (4), 2,9-di-methyl-1,10-phenanthrolineaquadichlorocopper(II) {[(di-methyl)phen) Cu(H2O)Cl2}(5), μ-dichloro-bis{6-sec-butyl-2,2'-bipyridinedichlorocopper(II)} {((mono-sec-butyl)bipy) ClCu(μ-Cl)2CuCl((mono-sec-butyl)bipy)} (6), 6,6'-di-methyl-2,2'-bipyridinedichlorocopper(II) {(6,6'-di-methyl)bipy) CuCl2} (7), and 4,4'-dimethyl-2,2'-bipyridinedichlorocopper(II) {(4,4'-di-methyl)bipy) CuCl2} (8). These complexes have been characterized via elemental analysis, UV-vis spectroscopy, and mass spectrometry. Single crystal X-ray diffraction experiments revealed the complexes synthesized with the (di-sec-butyl)phen ligand (1) and (mono-sec-butyl)bipy ligand (6) crystallized as dimers in which two copper(II) centers are bridged by two chloride ligands. Conversely, complexes 2, 7, and 8 were isolated as monomeric species possessing distorted tetrahedral geometries, and the [((di-methyl)phen)Cu(H2O)Cl2] (5) complex was isolated as a distorted square pyramidal monomer possessing a coordinating aqua ligand. Compounds 1-8 were evaluated for their in vitro antitumor efficacy. Compounds 1, 5, and 7 in particular were found to exhibit remarkable activity against human derived lung cancer cells, yet this class of copper(II) compounds had minimal cytotoxic effect on non-cancerous cells. In vitro control experiments indicate the activity of the copper(II) complexes most likely does not arise from the

  19. Silver sulfadoxinate: Synthesis, structural and spectroscopic characterizations, and preliminary antibacterial assays in vitro (United States)

    Zanvettor, Nina T.; Abbehausen, Camilla; Lustri, Wilton R.; Cuin, Alexandre; Masciocchi, Norberto; Corbi, Pedro P.


    The sulfa drug sulfadoxine (SFX) reacted with Ag+ ions in aqueous solution, affording a new silver(I) complex (AgSFX), which was fully characterized by chemical, spectroscopic and structural methods. Elemental, ESI-TOF mass spectrometric and thermal analyses of AgSFX suggested a [Ag(C12H13N4O2S)] empirical formula. Infrared spectroscopic measurements indicated ligand coordination to Ag(I) through the nitrogen atoms of the (deprotonated) sulfonamide group and by the pyrimidine ring, as well as through oxygen atom(s) of the sulfonamide group. These hypotheses were corroborated by 13C and 15N SS-NMR spectroscopy and by an unconventional structural characterization based on X-ray powder diffraction data. The latter showed that AgSFX crystallizes as centrosymmetric dimers with a strong Ag⋯Ag interaction of 2.7435(6) Å, induced by the presence of exo-bidentate N,N‧ bridging ligands and the formation of an eight-membered ring of [AgNCN]2 sequence, nearly planar. Participation of oxygen atoms of the sulfonamide residues generates in the crystal a 1D coordination polymer, likely responsible for its very limited solubility in all common solvents. Besides the analytical, spectroscopic and structural description, the antibacterial properties of AgSFX were assayed using disc diffusion methods against Escherichia coli and Pseudomonas aeruginosa (Gram-negative), and Staphylococcus aureus (Gram-positive) bacterial strains. The AgSFX complex showed to be active against Gram-positive and Gram-negative bacterial strains, being comparable to the activities of silver sulfadiazine.

  20. Electron structure of superheavy elements Uut, Fl and Uup (Z=113 to 115)

    Energy Technology Data Exchange (ETDEWEB)

    Dzuba, V. A., E-mail:; Flambaum, V. V. [University of New South Wales, School of Physics (Australia)


    We use recently developed method of accurate atomic calculations which combines linearized single-double coupled cluster method with the configuration interaction technique to calculate ionisation potentials, excitation energies, static polarizabilities and valence electron densities for superheavy elements Uut, Fl and Uup (Z=113 to 115) and their ions. The accuracy of the calculations is controlled by comparing similar calculations for lighter analogs of the superheavy elements, Tl, Pb and Bi with experiment. The role of relativistic effects and correlations is discussed and comparison with earlier calculations is presented.

  1. Electron structure of superheavy elements Uut, Fl and Uup ( Z=113 to 115) (United States)

    Dzuba, V. A.; Flambaum, V. V.


    We use recently developed method of accurate atomic calculations which combines linearized single-double coupled cluster method with the configuration interaction technique to calculate ionisation potentials, excitation energies, static polarizabilities and valence electron densities for superheavy elements Uut, Fl and Uup ( Z=113 to 115) and their ions. The accuracy of the calculations is controlled by comparing similar calculations for lighter analogs of the superheavy elements, Tl, Pb and Bi with experiment. The role of relativistic effects and correlations is discussed and comparison with earlier calculations is presented.

  2. Correlation of finite-element structural dynamic analysis with measured free vibration characteristics for a full-scale helicopter fuselage (United States)

    Kenigsberg, I. J.; Dean, M. W.; Malatino, R.


    The correlation achieved with each program provides the material for a discussion of modeling techniques developed for general application to finite-element dynamic analyses of helicopter airframes. Included are the selection of static and dynamic degrees of freedom, cockpit structural modeling, and the extent of flexible-frame modeling in the transmission support region and in the vicinity of large cut-outs. The sensitivity of predicted results to these modeling assumptions are discussed. Both the Sikorsky Finite-Element Airframe Vibration analysis Program (FRAN/Vibration Analysis) and the NASA Structural Analysis Program (NASTRAN) have been correlated with data taken in full-scale vibration tests of a modified CH-53A helicopter.

  3. Impact of ICT on the structural and contextual organizational elements: Case of the Varaždin County

    Directory of Open Access Journals (Sweden)

    Kristina Brodar


    Full Text Available The influence of certain factors on the organizational components has been in researchers' focus for years, together with their impact on the overall organizational efficiency. Traditional view commonly divided the factors on internal and external ones, which became improper in modern conditions. With contemporary division on structural and contextual factors, as a specific determinant we have to extract information and communication technology (ICT which impacts elements of structural and contextual dimension in every organization. Therefore it is becoming generic factor which cannot be classified into one of these groups. In this research, we observed impact of ICT on organizational elements of public administrations offices on the case of the Varaždin County. Results show that this impact is present in various forms in all observed factors and thus makes ICT a generic organizational factor.

  4. Effects of surgical joint destabilization on load sharing between ligamentous structures in the thoracic spine: a finite element investigation. (United States)

    Little, J P; Adam, C J


    In vitro investigations have demonstrated the importance of the ribcage in stabilizing the thoracic spine. Surgical alterations of the ribcage may change load-sharing patterns in the thoracic spine. Computer models are used in this study to explore the effect of surgical disruption of the rib-vertebrae connections on ligament load-sharing in the thoracic spine. A finite element model of a T7-8 motion segment, including the T8 rib, was developed using CT-derived spinal anatomy for the Visible Woman. Both the intact motion segment and the motion segment with four successive stages of destabilization (discectomy and removal of right costovertebral joint, right costotransverse joint and left costovertebral joint) were analyzed for a 2000 Nmm moment in flexion/extension, lateral bending and axial rotation. Joint rotational moments were compared with existing in vitro data and a detailed investigation of the load sharing between the posterior ligaments carried out. The simulated motion segment demonstrated acceptable agreement with in vitro data at all stages of destabilization. Under lateral bending and axial rotation, the costovertebral joints were of critical importance in resisting applied moments. In comparison to the intact joint, anterior destabilization increases the total moment contributed by the posterior ligaments. Surgical removal of the costovertebral joints may lead to excessive rotational motion in a spinal joint, increasing the risk of overload and damage to the remaining ligaments. The findings of this study are particularly relevant for surgical procedures involving rib head resection, such as some techniques for scoliosis deformity correction. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Differential contribution of cis-regulatory elements to higher order chromatin structure and expression of the CFTR locus


    Yang, Rui; Kerschner, Jenny L.; Gosalia, Nehal; Neems, Daniel; Gorsic, Lidija K.; Safi, Alexias; Crawford, Gregory E.; Kosak, Steven T.; Leir, Shih-Hsing; Harris, Ann


    Higher order chromatin structure establishes domains that organize the genome and coordinate gene expression. However, the molecular mechanisms controlling transcription of individual loci within a topological domain (TAD) are not fully understood. The cystic fibrosis transmembrane conductance regulator (CFTR) gene provides a paradigm for investigating these mechanisms. CFTR occupies a TAD bordered by CTCF/cohesin binding sites within which are cell-type-selective cis-regulatory elements for ...

  6. The behavior of osmium and other siderophile elements during impacts: Insights from the Ries impact structure and central European tektites

    Czech Academy of Sciences Publication Activity Database

    Ackerman, Lukáš; Magna, T.; Žák, Karel; Skála, Roman; Jonášová, Šárka; Mizera, Jiří; Řanda, Zdeněk


    Roč. 210, 1 August (2017), s. 59-70 ISSN 0016-7037 R&D Projects: GA ČR GA13-22351S; GA MŠk LM2015056 Institutional support: RVO:67985831 ; RVO:61389005 Keywords : highly siderophile elements * meteoritic component * Osmium isotopes * Ries impact structure * tektite Subject RIV: DB - Geology ; Mineralogy; BG - Nuclear, Atomic and Molecular Physics, Colliders (UJF-V) Impact factor: 4.609, year: 2016


    Directory of Open Access Journals (Sweden)

    Eduard Andrei CIOCĂNESCU


    Full Text Available The main purpose of the following article is to present, based on the Eurostat and INS research, the structure of the Romanian immigrants according to age and sex. The second objective of this article is to show the impact that the external migration phenomenon has on labour market at national level.The approaches are quantitative and specific elements of the descriptive statistics and more advanced procedures of the analysis of the bounds between variables are being used.

  8. Semantic Elements in Deep Structures as Seen from a Modernist Definition of Clarity. (United States)

    Lemke, Alan

    Typically, teachers approach ambiguity in student writing by suggesting that students focus on diction, syntax, and writing format; however, the works of modernists (including T.S. Eliot, Ludwig Wittgenstein, Karl Marx, and Pablo Picasso) suggest the importance of conceptions of semantic clarity. Transformational models for syntactic elements in…

  9. Human Learning of Elemental Category Structures: Revising the Classic Result of Shepard, Hovland, and Jenkins (1961) (United States)

    Kurtz, Kenneth J.; Levering, Kimery R.; Stanton, Roger D.; Romero, Joshua; Morris, Steven N.


    The findings of Shepard, Hovland, and Jenkins (1961) on the relative ease of learning 6 elemental types of 2-way classifications have been deeply influential 2 times over: 1st, as a rebuke to pure stimulus generalization accounts, and again as the leading benchmark for evaluating formal models of human category learning. The litmus test for models…

  10. Local buckling of aluminium structures exposed to fire. Part 2: Finite element models

    NARCIS (Netherlands)

    Maljaars, J.; Soetens, F.


    A test series was carried out and reported in a corresponding paper on slender aluminium alloy sections, loaded in compression at elevated temperature. This paper gives the results of simulations of these tests with a finite element model. For this purpose, a novel constitutive model for fire

  11. 3-D stochastic finite elements for thermal creep analysis of piping structures with spatial material inhomogeneities

    NARCIS (Netherlands)

    Appalanaidu, Y.; Roy, A.; Gupta, S.


    A stochastic finite element-based methodology is developed for creep damage assessment in pipings carrying high-temperature fluids. The material properties are assumed to be spatially randomly inhomogeneous and are modelled as 3-D non-Gaussian fields. A spectral-based approach for random field

  12. Direct Determination of Asymptotic Structural Postbuckling Behaviour by the finite element method

    DEFF Research Database (Denmark)

    Poulsen, Peter Noe; Damkilde, Lars


    Application of the finite element method to Koiter's asymptotic postbuckling theory often leads to numerical problems. Generally it is believed that these problems are due to locking of non-linear terms of different orders. A general method is given here that explains the reason for the numerical...... convergence of the postbuckling coefficients. (C) 1998 John Wiley & Sons, Ltd....

  13. Application and Analysis of Sandwich Elements in the Primary Structure of Large Wind Turbine Blades

    DEFF Research Database (Denmark)

    Berggreen, Christian; Branner, Kim; Jensen, Jacob Fisker


    The present work studies the advantages of applying a sandwich construction as opposed to traditional single skin composites in the flanges of a load carrying spar in a future 180 m wind turbine rotor. A parametric finite element model is used to analyze two basic designs with single skin...

  14. Shape Effect of Electrochemical Chloride Extraction in Structural Reinforced Concrete Elements Using a New Cement-Based Anodic System

    Directory of Open Access Journals (Sweden)

    Jesús Carmona


    Full Text Available This article shows the research carried out by the authors focused on how the shape of structural reinforced concrete elements treated with electrochemical chloride extraction can affect the efficiency of this process. Assuming the current use of different anode systems, the present study considers the comparison of results between conventional anodes based on Ti-RuO2 wire mesh and a cement-based anodic system such as a paste of graphite-cement. Reinforced concrete elements of a meter length were molded to serve as laboratory specimens, to closely represent authentic structural supports, with circular and rectangular sections. Results confirm almost equal performances for both types of anode systems when electrochemical chloride extraction is applied to isotropic structural elements. In the case of anisotropic ones, such as rectangular sections with no uniformly distributed rebar, differences in electrical flow density were detected during the treatment. Those differences were more extreme for Ti-RuO2 mesh anode system. This particular shape effect is evidenced by obtaining the efficiencies of electrochemical chloride extraction in different points of specimens.

  15. Topology optimization of acoustic-structure interaction problems using a mixed finite element formulation

    DEFF Research Database (Denmark)

    Yoon, Gil Ho; Jensen, Jens Stissing; Sigmund, Ole


    The paper presents a gradient-based topology optimization formulation that allows to solve acoustic-structure (vibro-acoustic) interaction problems without explicit boundary interface representation. In acoustic-structure interaction problems, the pressure and displacement fields are governed...

  16. Improving Stiffness-to-weight Ratio of Spot-welded Structures based upon Nonlinear Finite Element Modelling (United States)

    Zhang, Shengyong


    Spot welding has been widely used for vehicle body construction due to its advantages of high speed and adaptability for automation. An effort to increase the stiffness-to-weight ratio of spot-welded structures is investigated based upon nonlinear finite element analysis. Topology optimization is conducted for reducing weight in the overlapping regions by choosing an appropriate topology. Three spot-welded models (lap, doubt-hat and T-shape) that approximate “typical” vehicle body components are studied for validating and illustrating the proposed method. It is concluded that removing underutilized material from overlapping regions can result in a significant increase in structural stiffness-to-weight ratio.

  17. An in vitro biofilm model associated to dental implants: structural and quantitative analysis of in vitro biofilm formation on different dental implant surfaces. (United States)

    Sánchez, M C; Llama-Palacios, A; Fernández, E; Figuero, E; Marín, M J; León, R; Blanc, V; Herrera, D; Sanz, M


    The impact of implant surfaces in dental biofilm development is presently unknown. The aim of this investigation was to assess in vitro the development of a complex biofilm model on titanium and zirconium implant surfaces, and to compare it with the same biofilm formed on hydroxyapatite surface. Six standard reference strains were used to develop an in vitro biofilm over sterile titanium, zirconium and hydroxyapatite discs, coated with saliva within the wells of pre-sterilized polystyrene tissue culture plates. The selected species used represent initial (Streptococcus oralis and Actinomyces naeslundii), early (Veillonella parvula), secondary (Fusobacterium nucleatum) and late colonizers (Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans). The developed biofilms (growth time 1 to 120h) were studied with confocal laser scanning microscopy using a vital fluorescence technique and with low-temperature scanning electron microscopy. The number (colony forming units/biofilm) and kinetics of the bacteria within the biofilm were studied with quantitative PCR (qPCR). As outcome variables, the biofilm thickness, the percentage of cell vitality and the number of bacteria were compared using the analysis of variance. The bacteria adhered and matured within the biofilm over the three surfaces with similar dynamics. Different surfaces, however, demonstrated differences both in the thickness, deposition of the extracellular polysaccharide matrix as well as in the organization of the bacterial cells. While the formation and dynamics of an in vitro biofilm model was similar irrespective of the surface of inoculation (hydroxyapatite, titanium or zirconium), there were significant differences in regards to the biofilm thickness and three-dimensional structure. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  18. Numerical and Experimental Study on Integration of Control Actions into the Finite Element Solutions in Smart Structures

    Directory of Open Access Journals (Sweden)

    L. Malgaca


    Full Text Available Piezoelectric smart structures can be modeled using commercial finite element packages. Integration of control actions into the finite element model solutions (ICFES can be done in ANSYS by using parametric design language. Simulation results can be obtained easily in smart structures by this method. In this work, cantilever smart structures consisting of aluminum beams and lead-zirconate-titanate (PZT patches are considered. Two cases are studied numerically and experimentally in parallel. In the first case, a smart structure with a single PZT patch is used for the free vibration control under an initial tip displacement. In the second case, a smart structure with two PZT patches is used for the forced vibration control under harmonic excitation, where one of the PZT patches is used as vibration generating shaker while the other is used as vibration controlling actuator. For the two cases, modal analyses are done using chirp signals; Control OFF and Control ON responses in the time domain are obtained for various controller gains. A non-contact laser displacement sensor and strain gauges are utilized for the feedback signals. It is observed that all the simulation results agree with the experimental results.

  19. Stress Analysis of Osteoporotic Lumbar Vertebra Using Finite Element Model with Microscaled Beam-Shell Trabecular-Cortical Structure

    Directory of Open Access Journals (Sweden)

    Yoon Hyuk Kim


    Full Text Available Osteoporosis is a disease in which low bone mass and microarchitectural deterioration of bone tissue lead to enhanced bone fragility and susceptibility to fracture. Due to the complex anatomy of the vertebral body, the difficulties associated with obtaining bones for in vitro experiments, and the limitations on the control of the experimental parameters, finite element models have been developed to analyze the biomechanical properties of the vertebral body. We developed finite element models of the L2 vertebra, which consisted of the endplates, the trabecular lattice, and the cortical shell, for three age-related grades (young, middle, and old of osteoporosis. The compressive strength and stiffness results revealed that we had developed a valid model that was consistent with the results of previous experimental and computational studies. The von-Mises stress, which was assumed to predict the risk of a burst fracture, was also determined for the three age groups. The results showed that the von-Mises stress was substantially higher under relatively high levels of compressive loading, which suggests that patients with osteoporosis should be cautious of fracture risk even during daily activities.

  20. Using invariom modelling to distinguish correct and incorrect central atoms in `duplicate structures' with neighbouring 3d elements. (United States)

    Wandtke, Claudia M; Weil, Matthias; Simpson, Jim; Dittrich, Birger


    Modelling coordination compounds has been shown to be feasible using the invariom method; for the best fit to a given set of diffraction data, additional steps other than using lookup tables of scattering factors need to be carried out. Here such procedures are applied to a number of `duplicate structures', where structures of two or more supposedly different coordination complexes with identical ligand environments, but with different 3d metal ions, were published. However, only one metal atom can be plausibly correct in these structures, and other spectroscopic data are unavailable. Using aspherical scattering factors, a structure can be identified as correct from the deposited Bragg intensities alone and modelling only the ligand environment often suffices to make this distinction. This is not possible in classical refinements using the independent atom model. Quantum-chemical computations of the better model obtained after aspherical-atom refinement further confirm the assignment of the element in the respective figures of merit.

  1. Application of layered finite elements in the numerical analysis of laminated composite and sandwich structures with delaminations

    Directory of Open Access Journals (Sweden)

    Vuksanović Đorđe


    Full Text Available Laminar composites are modern engineering materials widely used in the mechanical and civil engineering. In the paper, some recent advances in a numerical analysis of laminated composite and sandwich plates and shells of different shapes, with existing zones of partial delamination, are presented. The layered finite elements, based on the extended version of the Generalized Laminated Plate Theory of Reddy, are applied for the numerical solution of several structural problems. After the verification of the proposed model for intact structures using the existing data from the literature, the effects of the size and the position of embedded delamination zones on the structural response of laminated structures are investigated numerically by means of a variety of numerical applications.

  2. Synthesis and in vitro antioxidant and antimicrobial studies of novel structured phosphatidylcholines with phenolic acids. (United States)

    Balakrishna, Marrapu; Kaki, Shiva Shanker; Karuna, Mallampalli S L; Sarada, Sripada; Kumar, C Ganesh; Prasad, R B N


    Novel phenoylated phosphatidylcholines were synthesized from 1,2-dipalmitoyl phosphatidylcholine/egg 1,2-diacyl phosphatidylcholine and phenolic acids such as ferulic, sinapic, vanillic and syringic acids. The structures of phenoylated phosphatidylcholines were confirmed by spectral analysis. 2-acyl-1-lyso phosphatidylcholine was synthesized from phosphatidylcholine via regioselective enzymatic hydrolysis and was reacted with hydroxyl protected phenolic acids to produce corresponding phenoylated phosphatidylcholines in 48-56% yields. Deprotection of protected phenoylated phosphatidylcholines resulted in phenoylated phosphatidylcholines in 87-94% yields. The prepared compounds were evaluated for their preliminary in vitro antimicrobial and antioxidant activities. Among the active derivatives, compound 1-(4-hydroxy-3,5-dimethoxy) cinnamoyl-2-acyl-sn-glycero-3-phosphocholine exhibited excellent antioxidant activity with EC50 value of 16.43μg/mL. Compounds 1-(4-hydroxy-3-methoxy) cinnamoyl-2-acyl-sn-glycero-3-phosphocholine and 1-(4-hydroxy-3,5-dimethoxy) cinnamoyl-2-palmitoyl-sn-glycero-3-phosphocholine exhibited good antioxidant activity with EC50 values of 36.05 and 33.35μg/mL respectively. Compound 1-(4-hydroxy-3-methoxy) cinnamoyl-2-palmitoyl-sn-glycero-3-phosphocholine exhibited good antibacterial activity against Klebsiella planticola with MIC of 15.6μg/mL and compound 1-(4-hydroxy-3-methoxy) benzoyl-2-acyl-sn-glycero-3-phosphocholine exhibited good antifungal activity against Candida albicans with MIC of 15.6μg/mL. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. In vitro toxicological effects of estrogenic mycotoxins on human placental cells: Structure activity relationships

    Energy Technology Data Exchange (ETDEWEB)

    Prouillac, Caroline, E-mail: [Université Lyon, US/C 1233 INRA VetAgroSup, Métabolisme et Toxicologie Comparée des Xénobiotiques, 1 avenue Bourgelat, BP 83, 69280 Marcy l' Etoile (France); Koraichi, Farah; Videmann, Bernadette; Mazallon, Michelle [Université Lyon, US/C 1233 INRA VetAgroSup, Métabolisme et Toxicologie Comparée des Xénobiotiques, 1 avenue Bourgelat, BP 83, 69280 Marcy l' Etoile (France); Rodriguez, Frédéric; Baltas, Michel [Université Paul Sabatier, SPCMIB-UMR5068, Laboratoire de Synthèse et de Physicochimie des Molécules d' Intérêt Biologique, 118 route de Narbonne, 31062 TOULOUSE cedex 9 (France); Lecoeur, Sylvaine [Université Lyon, US/C 1233 INRA VetAgroSup, Métabolisme et Toxicologie Comparée des Xénobiotiques, 1 avenue Bourgelat, BP 83, 69280 Marcy l' Etoile (France)


    Zearalenone (ZEN) is a non-steroid estrogen mycotoxin produced by numerous strains of Fusarium which commonly contaminate cereals. After oral administration, ZEN is reduced via intestinal and hepatic metabolism to α- and β-zearalenol (αZEL and βZEL). These reduced metabolites possess estrogenic properties, αZEL showing the highest affinity for ERs. ZEN and reduced metabolites cause hormonal effects in animals, such as abnormalities in the development of the reproductive tract and mammary gland in female offspring, suggesting a fetal exposure to these contaminants. In our previous work, we have suggested the potential impact of ZEN on placental cells considering this organ as a potential target of xenobiotics. In this work, we first compared the in vitro effects of αZEL and βΖΕL on cell differentiation to their parental molecule on human trophoblast (BeWo cells). Secondly, we investigated their molecular mechanisms of action by investigating the expression of main differentiation biomarkers and the implication of nuclear receptor by docking prediction. Conversely to ZEN, reduced metabolites did not induce trophoblast differentiation. They also induced significant changes in ABC transporter expression by potential interaction with nuclear receptors (LXR, PXR, PR) that could modify the transport function of placental cells. Finally, the mechanism of ZEN differentiation induction seemed not to involve nuclear receptor commonly involved in the differentiation process (PPARγ). Our results demonstrated that in spite of structure similarities between ZEN, αZEL and βZEL, toxicological effects and toxicity mechanisms were significantly different for the three molecules. -- Highlights: ► ZEN and metabolites have differential effect on trophoblast differentiation. ► ZEN and metabolites have differential effect on ABC transporter expression. ► ZEN and metabolites effects involved nuclear receptors interaction.

  4. Formation of urothelial structures in vivo from dissociated cells attached to biodegradable polymer scaffolds in vitro. (United States)

    Atala, A; Vacanti, J P; Peters, C A; Mandell, J; Retik, A B; Freeman, M R


    The use of autologous urothelium would be advantageous for urothelial replacement in many genitourinary reconstructive procedures. Urothelial tissue grafts might be created using isolated populations of transitional epithelium or tissue in concert with an appropriate synthetic substrate. We describe the results of experiments designed to determine the feasibility of using biodegradable polymers as delivery vehicles for the creation of new urothelial structures in vivo from dissociated cells. Primary cultures enriched in uroepithelial cells were obtained from New Zealand white rabbits using a new technique of cell harvest. Cells were seeded onto nonwoven meshes of polyglycolic acid polymers in culture and, after 1 to 4 days in vitro, the cell-polymer scaffolds were implanted into the mesentery, omentum or retroperitoneum of athymic mice. Polymers implanted without cells served as controls. Animals were sacrificed at 5, 10, 20 and 30 days after implantation and 75 implants were examined histologically. Ten days after implantation isolated single cell layers were seen lining the polymer fibers. At 20 and 30 days polymer degradation was evident and urothelial cells lined the polymer in continuous layers of 1 to 3-cell thickness. Anticytokeratin western blots demonstrated the presence of a urothelium-associated cytokeratin in cell-polymer implants recovered after 30 days. These results demonstrate that urothelial cells can be successfully harvested, survive in culture and attach to artificial biodegradable polymers. The urothelial-polymer scaffolds can be implanted into host animals and the implanted cells can achieve spatial orientation as the polymer undergoes biodegradation. These findings suggest that it may be possible to use autologous urothelium, reconfigured on a synthetic substrate, in reconstructive procedures involving the ureter, bladder and urethra.

  5. Bisphenol A inhibits voltage-activated Ca(2+) channels in vitro: mechanisms and structural requirements. (United States)

    Deutschmann, André; Hans, Michael; Meyer, Rainer; Häberlein, Hanns; Swandulla, Dieter


    Bisphenol A (BPA), a high volume production chemical compound attracts growing attention as a health-relevant xenobiotic in humans. It can directly bind to hormone receptors, enzymes, and ion channels to become biologically active. In this study we show that BPA acts as a potent blocker of voltage-activated Ca(2+) channels. We determined the mechanisms of block and the structural elements of BPA essential for its action. Macroscopic Ba(2+) / Ca(2+) currents through native L-, N-, P/Q-, T-type Ca(2+) channels in rat endocrine GH(3) cells, mouse dorsal root ganglion neurons or cardiac myocytes, and recombinant human R-type Ca(2+) channels expressed in human embryonic kidney (HEK) 293 cells were rapidly and reversibly inhibited by BPA with similar potency (EC(50) values: 26-35 μM). Pharmacological and biophysical analysis of R-type Ca(2+) channels revealed that BPA interacts with the extracellular part of the channel protein. Its action does not require intracellular signaling pathways, is neither voltage- nor use-dependent, and does not affect channel gating. This indicates that BPA interacts with the channel in its resting state by directly binding to an external site outside the pore-forming region. Structure-effect analyses of various phenolic and bisphenolic compounds revealed that 1) a double-alkylated (R-C(CH(3))(2)-R, R-C(CH(3))(CH(2)CH(3))-R), or double-trifluoromethylated sp(3)-hybridized carbon atom between the two aromatic rings and 2) the two aromatic moieties in angulated orientation are optimal for BPA's effectiveness. Since BPA highly pollutes the environment and is incorporated into the human organism, our data may provide a basis for future studies relevant for human health and development.

  6. From particle cascade simulations (FLUKA) to finite element heat transfer and structural deformation analyses (ANSYS)

    CERN Document Server

    Zazula, J M


    Particle cascade simulations coupled with subsequent finite element thermal and mechanical calculations are an advanced, extremely useful, and sometimes the only available and reliable tool for solving practical as well as general engineering problems related to design and construction of accelerator components. The FLUKA Monte Carlo code and the ANSYS Finite Element system are extensively used by us for this purpose. In this paper we discuss physical assumptions made when using these programmes, modes of their applications, and their interface. Successful application of their mainframe for estimating spatial distributions and time evolution of temperatures and stresses in the accelerator domain are shown as examples : for the LHC and SPS beam dumps, and for the neutrino target at the SPS.

  7. Development of a user element in ABAQUS for modelling of cohesive laws in composite structures

    DEFF Research Database (Denmark)

    Feih, S.


    forward, and most existing publications consider theoretical and therefore simpler softening shapes. In this article, bridging laws were implemented intoan interface element in the UEL user subroutine in the finite element code ABAQUS. Comparison with different experimental data points for crack opening......The influence of different fibre sizings on the strength and fracture toughness of composites was studied by investigating the characteristics of fibre cross-over bridging in DCB specimens loaded with pure bending moments. These tests result in bridginglaws, which are obtained by simultaneous...... measurements of the crack growth resistance and the end opening of the notch. The advantage of this method is that these bridging laws represent material laws independent of the specimen geometry. However, theadaption of the experimentally determined shape to a numerically valid model shape is not straight...

  8. Structural changes of in vitro matured buffalo and bovine oocytes following cryopreservation


    Marina De Blasi; Evelina Mariotti; Salvatore Velotto; Marcello Rubessa; Serena Di Francesco; Bianca Gasparrini


    The aim of this work was to evaluate chromatin and spindle organization of buffalo and bovine in vitro matured oocytes after vitrification/warming by Cryotop and after their exposure to cryoprotectants (CP). In vitro matured oocytes were vitrified/warmed and exposed to the vitrification/warming solutions containing ethylene glycol (EG), dimethyl sulfoxide (DMSO) and sucrose as CP. Two hours after warming, oocytes were fixed and immunostained for microtubules and nuclei and examined by fluores...

  9. The value of structured data elements from electronic health records for identifying subjects for primary care clinical trials. (United States)

    Ateya, Mohammad B; Delaney, Brendan C; Speedie, Stuart M


    An increasing number of clinical trials are conducted in primary care settings. Making better use of existing data in the electronic health records to identify eligible subjects can improve efficiency of such studies. Our study aims to quantify the proportion of eligibility criteria that can be addressed with data in electronic health records and to compare the content of eligibility criteria in primary care with previous work. Eligibility criteria were extracted from primary care studies downloaded from the UK Clinical Research Network Study Portfolio. Criteria were broken into elemental statements. Two expert independent raters classified each statement based on whether or not structured data items in the electronic health record can be used to determine if the statement was true for a specific patient. Disagreements in classification were discussed until 100 % agreement was reached. Statements were also classified based on content and the percentages of each category were compared to two similar studies reported in the literature. Eligibility criteria were retrieved from 228 studies and decomposed into 2619 criteria elemental statements. 74 % of the criteria elemental statements were considered likely associated with structured data in an electronic health record. 79 % of the studies had at least 60 % of their criteria statements addressable with structured data likely to be present in an electronic health record. Based on clinical content, most frequent categories were: "disease, symptom, and sign", "therapy or surgery", and "medication" (36 %, 13 %, and 10 % of total criteria statements respectively). We also identified new criteria categories related to provider and caregiver attributes (2.6 % and 1 % of total criteria statements respectively). Electronic health records readily contain much of the data needed to assess patients' eligibility for clinical trials enrollment. Eligibility criteria content categories identified by our study can be

  10. 2D and 3D Finite Element Restorations of Geological Structures with Sliding Contact Along Faults


    Guiton, Martin; Zammali, Chokri


    International audience; A fully implicit finite element method is developed for the restoration of sedimentary basins. Internal deformationis distributed with a linear hyper-elasticity constitutive law. Deformation is also accommodated by large slidingalong faults. This mechanism is represented by a frictionless bilateral contact algorithm between deformablebodies. Application are shown with 2D forward or backward models of thrust related folding with multipleintersecting discontinuities. An ...

  11. Low cost fabrication of graphite epoxy column elements for large space structures (United States)

    Bluck, R. M.; Johnson, R.


    A procedure for fabricating graphite epoxy column elements used in the construction of large space platforms is described. Dry fiber is wound on a tapered aluminum mandrel in the LMSC vertical winding machine, and resin is injected between the mandrel and an outer sleeve. The winding and injection take place at elevated temperature to minimize the thermal expansion problems that arise in curing a tube on an aluminum mandrel when the end fittings are integrally wound.

  12. Main formulations of the finite element method for the problems of structural mechanics. Part 3

    Directory of Open Access Journals (Sweden)

    Ignat’ev Aleksandr Vladimirovich


    Full Text Available In this paper the author offers is the classification of the formulae of Finite Element Method. This classification help to orient in a huge number of published articles, as well as those to be published, which are dedicated to the problem of enhancing the efficiency of the most commonly used method. The third part of the article considers the variation formulations of FEM and the energy principles lying in the basis of it. If compared to the direct method, which is applied only to finite elements of a simple geometrical type, the variation formulations of FEM are applicable to the elements of any type. All the variation methods can be conventionally divided into two groups. The methods of the first group are based on the principle of energy functional stationarity - a potential system energy, additional energy or on the basis of these energies, which means the full energy. The methods of the second group are based on the variants of mathematical methods of weighted residuals for solving the differential equations, which in some cases can be handled according to the principle of possible displacements or extreme energy principles. The most widely used and multipurpose is the approach based on the use of energy principles coming from the energy conservation law: principle of possible changes in stress state, principle of possible change in stress-strain state.

  13. Composition Feature of the Element Tangent Stiffness Matrix of Geometrically Nonlinear 2D Frame Structures

    Directory of Open Access Journals (Sweden)

    Romanas Karkauskas


    Full Text Available The expressions of the finite element method tangent stiffness matrix of geometrically nonlinear constructions are not fully presented in publications. The matrixes of small displacements stiffness are usually presented only. To solve various problems of construction analysis or design and to specify the mode of the real deflection of construction, it is necessary to have a fully described tangent matrix analytical expression. This paper presents a technique of tangent stiffness matrix generation using discrete body total potential energy stationary conditions considering geometrically nonlinear 2D frame element taking account of interelement interaction forces only. The obtained vector-function derivative of internal forces considering nodal displacements is the tangent stiffness matrix. The analytical expressions having nodal displacements of matrixes forming the content of the 2D frame construction element tangent stiffness matrix are presented in the article. The suggested methodology has been checked making symbolical calculations in the medium of MatLAB calculation complex. The analytical expression of the stiffness matrix has been obtained.Article in Lithuanian

  14. Head-Neck Osteoplasty has Minor Effect on the Strength of an Ovine Cam-FAI Model: In Vitro and Finite Element Analyses. (United States)

    Maquer, Ghislain; Bürki, Alexander; Nuss, Katja; Zysset, Philippe K; Tannast, Moritz


    deeper resections. However, under in vitro testing conditions, the effect on femoral strength remains small even after 9 mm correction, suggesting that femoral head-neck osteochondroplasty could be done safely on the ovine femur. QCT-based finite element models were able to predict weakening of the femur resulting from the osteochondroplasty. The ovine femur provides a seemingly safe platform for scientific evaluation of FAI. It also appears that computer models based on preoperative CT scans may have the potential to provide patient-specific guidelines for preventing overcorrection of cam FAI.

  15. Protein energetic conformational analysis from NMR chemical shifts (PECAN) and its use in determining secondary structural elements

    Energy Technology Data Exchange (ETDEWEB)

    Eghbalnia, Hamid R.; Wang Liya; Bahrami, Arash [National Magnetic Resonance Facility at Madison, Biochemistry Department (United States); Assadi, Amir [University of Wisconsin-Madison, Mathematics Department (United States); Markley, John L. [National Magnetic Resonance Facility at Madison, Biochemistry Department (United States)], E-mail:


    We present an energy model that combines information from the amino acid sequence of a protein and available NMR chemical shifts for the purposes of identifying low energy conformations and determining elements of secondary structure. The model ('PECAN', Protein Energetic Conformational Analysis from NMR chemical shifts) optimizes a combination of sequence information and residue-specific statistical energy function to yield energetic descriptions most favorable to predicting secondary structure. Compared to prior methods for secondary structure determination, PECAN provides increased accuracy and range, particularly in regions of extended structure. Moreover, PECAN uses the energetics to identify residues located at the boundaries between regions of predicted secondary structure that may not fit the stringent secondary structure class definitions. The energy model offers insights into the local energetic patterns that underlie conformational preferences. For example, it shows that the information content for defining secondary structure is localized about a residue and reaches a maximum when two residues on either side are considered. The current release of the PECAN software determines the well-defined regions of secondary structure in novel proteins with assigned chemical shifts with an overall accuracy of 90%, which is close to the practical limit of achievable accuracy in classifying the states.

  16. Experimental research and use of finite elements method on mechanical behaviors of honeycomb structures assembled with epoxy-based adhesives reinforced with nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Akkus, Harun [Technical Sciences Vocational School, Amasya University, Amasya (Turkmenistan); Duzcukoglu, Hayrettin; Sahin, Omer Sinan [Mechanical Engineering Department, Selcuk University, Selcuk (Turkmenistan)


    This study utilized experimental and finite element methods to investigate the mechanical behavior of aluminum honeycomb structures under compression. Aluminum honeycomb composite structures were subjected to pressing experiments according to the standard ASTM C365. Resistive forces in response to compression and maximum compressive force values were measured. Structural damage was observed. In the honeycomb structure, the cell width decreased as the compressive force increased. Results obtained with finite element models generated using ANSYS Workbench 15 were validated. Experimental results paralleled the finite element modeling results. The ANSYS results were approximately 85 % reliable.

  17. Three-dimensional finite element analysis of stress distribution in a tooth restored with metal and fiber posts of varying diameters: An in-vitro study (United States)

    Kumar, Pradeep; Rao, R. Nageswar


    Objective: To compare stress distribution in a tooth restored with metal and fiber posts of varying diameters (1.2 and 1.4 mm) by means of three-dimensional finite element analysis (3D-FEA). Materials and Methods: Four 3D-FEA models were constructed: (1) fiber post (1.2 and 1.4 mm) and (2) metal post (1.2 and 1.4 mm). The material properties were assigned and a force of 100 N was applied at 45° angle to the longitudinal axis of the tooth onto the palatal surface incisal to the cingulum. Analysis was run and stress distribution pattern was studied. Results: Maximum stresses in the radicular tooth structure for fiber post were higher than that for metal post. In the former models, stresses in the tooth structure were slightly reduced with increase in fiber post diameter. Conclusions: To reduce stress in the remaining radicular tooth structure, it is better to use a fiber post of a large diameter. PMID:25829685

  18. Generic structure and promotional elements in best-selling online book blurbs: a cross-cultural study

    Directory of Open Access Journals (Sweden)

    Neslihan Önder


    Full Text Available This study investigates the generic structure and promotional elements of the online fiction blurbs accompanying the 95 best-selling books from Amazon United Kingdom and Okuoku Turkey (1999-2011, a company that sells books online that are written in Turkish or translated into Turkish, and adds to the growing number of investigations into this genre (Kathpalia, 1997; Bhatia, 2004; Cacchiani, 2007; Gea-Valor, 2007; Gesuato, 2007; Basturkmen, 2009. Based on the findings, a two-level schematic structure (moves and steps is proposed for the blurbs following Swales (1990. The findings suggest that Amazon UK book blurbs have a six-move schematic structure: complimenting the author, book description, justifying the book by establishing a niche, book promotion, author’s background and author’s website/blog being the second, fourth and fifth obligatory moves. However, Okuoku book blurbs feature a five-move schematic structure with complimenting the author, book description, involving the reader in the text, book promotion and author’s background, the second and fourth being obligatory. Analysis of promotional elements in the corpora reveals that online fiction book blurbs employ the art of advertising through the use of favorable expressions (Bhatia, 2005 and innovative uses of rhetorical strategies to persuade the reader to read the book.

  19. Integrated non-destructive assessment of relevant structural elements of an Italian heritage site: the Carthusian monastery of Trisulti (United States)

    Rainieri, C.; Marra, A.; Rainieri, G. M.; Gargaro, D.; Pepe, M.; Fabbrocino, G.


    The analysis of historical structures in need of preservation and restoration interventions is a very complex task due to the large uncertainties in the characterization of structural properties and detailing in view of the structural response. Moreover, the predictive performance of numerical analyses and simulations depend on the availability of information about the constructional properties of the architectural complex, crack patterns and active degradation phenomena. In particular, local changes in material properties or damage due to past events (such as earthquakes) can affect individual structural elements. They can be hardly detected as a result of the maintenance interventions carried out over the centuries and the possibility to carry out limited or even no destructive investigations due to the historical relevance of the structure. Thus, non-destructive investigations play a fundamental role in the assessment of historical structures minimizing, at the same time, the invasiveness of interventions. The present paper deals with an explanatory case study concerning the structural investigations carried out in view of the seismic assessment of an Italian historical monument, the Carthusian monastery of Trisulti in Collepardo, erected in 1204 under Pope Innocenzo HI. The relevance of the case study is due to the application, in combination, of different NDT methods, such as sonic tests, and active and passive infrared thermography, in order to characterize relevant masonry elements. Moreover, an advanced system for the in-situ nondestructive vibration-based estimation of the tensile loads in ancient tie-rods is described and the main results obtained from its application for the characterization of the tie-rods of the cloister are presented.

  20. Cross-Sectional Information on Pore Structure and Element Distribution of Sediment Particles by SEM and EDS

    Directory of Open Access Journals (Sweden)

    Minghong Chen


    Full Text Available The interaction between pollutants and sediment particles often occurs on the particle surface, so surface properties directly affect surface reaction. The physical and chemical processes occurring on sediment particle surfaces are microscopic processes and as such need to be studied from a microscopic perspective. In this study, field emission scanning electron microscopy (SEM and energy dispersive X-ray spectrometer (EDS were adopted to observe and analyze the pore structure and element distribution of sediment particles. In particular, a special method of sample preparation was used to achieve the corresponding cross-sectional information of sediment particles. Clear images of a particle profile and pore microstructure were obtained by high-resolution SEM, while element distribution maps of sediment particles were obtained by EDS. The results provide an intuitive understanding of the internal microenvironment and external behavior of sediment particles, in addition to revealing a significant role of pore microstructure in the adsorption and desorption of pollutants. Thus, a combination of different experimental instruments and observation methods can provide real images and information on microscopic pore structure and element distribution of sediment particles. These results should help to improve our understanding of sediment dynamics and its environmental effects.

  1. Detection of Earthquake-Induced Damage in a Framed Structure Using a Finite Element Model Updating Procedure (United States)

    Kim, Seung-Nam; Park, Taewon; Lee, Sang-Hyun


    Damage of a 5-story framed structure was identified from two types of measured data, which are frequency response functions (FRF) and natural frequencies, using a finite element (FE) model updating procedure. In this study, a procedure to determine the appropriate weightings for different groups of observations was proposed. In addition, a modified frame element which included rotational springs was used to construct the FE model for updating to represent concentrated damage at the member ends (a formulation for plastic hinges in framed structures subjected to strong earthquakes). The results of the model updating and subsequent damage detection when the rotational springs (RS model) were used were compared with those obtained using the conventional frame elements (FS model). Comparisons indicated that the RS model gave more accurate results than the FS model. That is, the errors in the natural frequencies of the updated models were smaller, and the identified damage showed clearer distinctions between damaged and undamaged members and was more consistent with observed damage. PMID:24574888

  2. Direct determination of asymptotic structural postbuckling behaviour by the finite element method

    DEFF Research Database (Denmark)

    Poulsen, Peter Noe; Damkilde, Lars


    Application of the Finite Element Method to Koiter's asymptotic postbuckling theory often leads to numerical problems. Generally it is believed that these problems are due to locking of nonlinear terms of different orders. A general method is given here that explains the reason for the numerical...... problems and eliminates these problems. The reason for the numerical problems is that the postbuckling stresses are inaccurately determined. By including a local stress contribution the postbuckling stresses are calculated correctly. The present method gives smooth postbuckling stresses and shows a quick...

  3. Molecular structure of canine LINE-1 elements in canine transmissible venereal tumor. (United States)

    Choi, Y; Ishiguro, N; Shinagawa, M; Kim, C J; Okamoto, Y; Minami, S; Ogihara, K


    We determined the 4251-bp sequence of open reading frame 2 (ORF2) of canine LINE-1 retroposon that encodes 1275 amino acids. The truncated LINE-1 inserts associated with transmissible venereal tumor (TVT) of dogs contained the 1378-bp LINE-1 insert (TVT-LINE) flanked by 10-bp direct repeats upstream to c-myc gene. The TVT-LINE elements were composed of 416 bp inverse sequences homologous to the complementary strand of the LINE-1, a 5-bp deletion and 962-bp sequences homologous to the 3' region of the LINE-1.

  4. A smoothed finite element approach for computational fluid dynamics: applications to incompressible flows and fluid-structure interaction (United States)

    He, Tao; Zhang, Hexin; Zhang, Kai


    In this paper the cell-based smoothed finite element method (CS-FEM) is introduced into two mainstream aspects of computational fluid dynamics: incompressible flows and fluid-structure interaction (FSI). The emphasis is placed on the fluid gradient smoothing which simply requires equal numbers of Gaussian points and smoothing cells in each four-node quadrilateral element. The second-order, smoothed characteristic-based split scheme in conjunction with a pressure stabilization is then presented to settle the incompressible Navier-Stokes equations. As for FSI, CS-FEM is applied to the geometrically nonlinear solid as usual. Following an efficient mesh deformation strategy, block-Gauss-Seidel procedure is adopted to couple all individual fields under the arbitrary Lagriangian-Eulerian description. The proposed solvers are carefully validated against the previously published data for several benchmarks, revealing visible improvements in computed results.

  5. Development and demonstration of manufacturing processes for fabricating graphite/Larc-160 polyimide structural elements, part 4, paragraph C (United States)


    Progress in the development of processes for production of Celion/LARC-160 graphite-polyimide materials, quality control methods, and the fabrication of Space Shuttle composite structure components is reported. The formulation and processing limits for three batches of resin are presented. Process improvements for simplification of the imidizing and autoclave cure cycles are described. Imidized and autoclave cured test panels were prepared. Celion/LARC-160 cure process verification and the fabrication of honeycomb sandwich panel elements and skin/stringer panels are described. C-scans of laminates imidized at 163 C to 218 C for periods from 30 to 180 minutes, and of process verification laminates made from different batches of prepreg are presented. Failure modes and load/strain characteristics of sandwich elements and C-scans of stringer to skin bond joints are also given.

  6. On the possibility of using multi-element phased arrays for shock-wave action on deep brain structures (United States)

    Rosnitskiy, P. B.; Gavrilov, L. R.; Yuldashev, P. V.; Sapozhnikov, O. A.; Khokhlova, V. A.


    A noninvasive ultrasound surgery method that relies on using multi-element focused phased arrays is being successfully used to destroy tumors and perform neurosurgical operations in deep structures of the human brain. However, several drawbacks that limit the possibilities of the existing systems in their clinical use have been revealed: a large size of the hemispherical array, impossibility of its mechanical movement relative to the patient's head, limited volume of dynamic focusing around the center of curvature of the array, and side effect of overheating skull. Here we evaluate the possibility of using arrays of smaller size and aperture angles to achieve shock-wave formation at the focus for thermal and mechanical ablation (histotripsy) of brain tissue taking into account current intensity limitations at the array elements. The proposed approach has potential advantages to mitigate the existing limitations and expand the possibilities of transcranial ultrasound surgery.

  7. Topology optimization using bi-directional evolutionary structural optimization based on the element-free Galerkin method (United States)

    Shobeiri, Vahid


    In this article, the bi-directional evolutionary structural optimization (BESO) method based on the element-free Galerkin (EFG) method is presented for topology optimization of continuum structures. The mathematical formulation of the topology optimization is developed considering the nodal strain energy as the design variable and the minimization of compliance as the objective function. The EFG method is used to derive the shape functions using the moving least squares approximation. The essential boundary conditions are enforced by the method of Lagrange multipliers. Several topology optimization problems are presented to show the effectiveness of the proposed method. Many issues related to topology optimization of continuum structures, such as chequerboard patterns and mesh dependency, are studied in the examples.

  8. Guided Waves in Structures for SHM The Time - domain Spectral Element Method

    CERN Document Server

    Ostachowicz, Wieslaw; Krawczuk, Marek; Zak, Arkadiusz


    Presents the state of the art in the modelling, analysis and experimental investigation of elastic wave propagation using a technique of rapidly increasing interest and development Addressing an important issue in the field of guided-wave-based damage identification and structural health monitoring,Guided Waves in Structures for SHM presents the modelling, analysis and experimental investigation of elastic wave propagation in engineering structures made of isotropic or composite materials. The authors begin by summarising present-day knowledge on elastic wave propagation in solids, focusing on

  9. Comparative structural morphometry and elemental composition of three marine sponges from western coast of India. (United States)

    Kumar, Maushmi S; Shah, Bhaumik


    Three marine sponges Halichondria glabrata, Cliono lobata, and Spirastrella pachyspira from the western coastal region of India were compared for their morphometry, biochemical, and elemental composition. One-way analysis of variance was applied for spicule morphometry results. Length, width, and length:width ratio were calculated independently. The ratio of length:width varied from 35 to 42 among the grown samples, which remained in the range of 10-22 in young sample at the beginning of studies. However, no significant change was observed in spicule width compared to length. Elemental compositions of marine sponges were determined by field emission gun-scanning electron microscope. Scanning electron microscopy data revealed that the spicules of all the three sponges were mostly composed of O (47-56%) and Si (30-40%), whereas Al (14.33%) was only detected in the spicules of C. lobata. Apart from these, K, Ni, Ca, Fe, Mg, Na, and S were additionally detected in all the three samples. Presence of heavy metals in the sponges was analyzed by inductively coupled plasma-atomic emission spectroscopy. Results showed that iron was present in a large amount in samples, followed by zinc, lead, and copper. Copyright © 2014 Wiley Periodicals, Inc.

  10. Geometric effect of the hydrogel grid structure on in vitro formation of homogeneous MIN6 cell clusters. (United States)

    Bae, Chae Yun; Min, Mun-kyeong; Kim, Hail; Park, Je-Kyun


    A microstructure-based hydrogel was employed to study the relationship between spatial specificity and cellular behavior, including cell fate, proliferation, morphology, and insulin secretion in pancreatic β-cells. To effectively form homogeneous cell clusters in vitro, we made cell-containing hydrogel membrane constructs with an adapted grid structure based on a hexagonal micropattern. Homogeneous cell clusters (average diameter: 83.6 ± 14.2 μm) of pancreatic insulinoma (MIN6) cells were spontaneously generated in the floating hydrogel membrane constructs, including a hexagonal grid structure (size of cavity: 100 μm, interval between cavities: 30 μm). Interestingly, 3D clustering of MIN6 cells mimicking the structure of pancreatic islets was coalesced into a merged aggregate attaching to each hexagonal cavity of the hydrogel grid structure. The fate and insulin secretion of homogeneous cell clusters in the hydrogel grid structure were also assessed. The results of these designable hydrogel-cell membrane constructs suggest that facultative in vitro β-cell proliferation and maintenance can be applied to biofunctional assessments.

  11. Near-surface structural examination of human tooth enamel subject to in vitro demineralization and remineralization (United States)

    Gaines, Carmen Veronica

    The early stages of chemical tooth decay are governed by dynamic processes of demineralization and remineralization of dental enamel that initiates along the surface of the tooth. Conventional diagnostic techniques lack the spatial resolution required to analyze near-surface structural changes in enamel at the submicron level. In this study, slabs of highly-polished, decay-free human enamel were subjected to 0.12M EDTA and buffered lactic acid demineralizing agents and MI Paste(TM) and calcifying (0.1 ppm F) remineralizing treatments in vitro. Grazing incidence x-ray diffraction (GIXD), a technique typically used for thin film analysis, provided depth profiles of crystallinity changes in surface enamel with a resolution better than 100 nm. In conjunction with nanoindentation, a technique gaining acceptance as a means of examining the mechanical properties of sound enamel, these results were corroborated with well-established microscopy and Raman techniques to assess the nanohardness, morphologies and chemical nature of treated enamel. Interestingly, the average crystallite size of surface enamel along its c-axis dimension increased by nearly 40% after a 60 min EDTA treatment as detected by GIXD. This result was in direct contrast to the obvious surface degradation observed by microscopic and confocal Raman imaging. A decrease in nanohardness from 4.86 +/- 0.44 GPa to 0.28 +/- 0.10 GPa was observed. Collective results suggest that mineral dissolution characteristics evident on the micron scale may not be fully translated to the nanoscale in assessing the integrity of chemically-modified tooth enamel. While an intuitive decrease in enamel crystallinity was observed with buffered lactic acid-treated samples, demineralization was too slow to adequately quantify the enamel property changes seen. MI Paste(TM) treatment of EDTA-demineralized enamel showed preferential growth along the a-axis direction. Calcifying solution treatments of both demineralized sample types

  12. Hybrid Element Method for Compsoite Structures Subjected to Boundary Layer Loading Project (United States)

    National Aeronautics and Space Administration — In many situations, aerospace structures are subjected to a wide frequency spectrum of mechanical and/or acoustic excitations and therefore, there is a need for the...

  13. A finite element formulation with combined loadings for shear dominant RC structures. (United States)


    Inelastic failure of reinforced concrete (RC) structures under seismic loadings can be due either to loss of flexural, shear or bond : capacity. Specifically, the effect of combined loadings can lead to a complex failure mechanism that plays a vital ...

  14. Structural assessment of aerospace components using image processing algorithms and Finite Element models

    DEFF Research Database (Denmark)

    Stamatelos, Dimtrios; Kappatos, Vassilios


    Purpose – This paper presents the development of an advanced structural assessment approach for aerospace components (metallic and composites). This work focuses on developing an automatic image processing methodology based on Non Destructive Testing (NDT) data and numerical models, for predicting...... of the damaged plates showed that strength reduction occurs compare to reference plates. This methodology is a promising method for structural assessment of aerospace components, since conclusions regarding their functionality can be drawn. Research limitations/implications – The investigated structural...... in a tough economic area. Originality/value – As far as it is known, this is the first time that an aerospace structural assessment combines image processing algorithms and FE models....

  15. Development of a Finite Element Methodology for the Collapse Analysis of Composite Aerospace Structures


    Orifici, Adrian; Thomson, Rodney; Degenhardt, Richard


    In this work, an analysis methodology for capturing the critical damage mechanisms leading to collapse in composite stiffened structures is proposed. One aspect of the methodology is a global-local analysis technique that monitors a strength criterion in three-dimensional local models to predict the initiation of interlaminar damage in intact structures. Another aspect of the approach was developed for representing the growth of a pre-existing interlaminar damage region such as a delamination...

  16. Contribution of Shape Memory Alloys Elements in Designing Underwater Smart Structures

    Directory of Open Access Journals (Sweden)

    Daniel Amariei


    Full Text Available Shape memory alloys (SMA have generated a lot of new ideas in engineering. Application is however so far limited to clamps and springs. With respect to smart structures sensing as well as control has to be included. While sensing looks to be relatively feasible control is the big challenge. This paper describes some related a smart structure idea using SMAs and discusses the challenges which need to be solved before these ideas can be realised.

  17. Validating a Finite Element Model of a Structure Subjected to Mine Blast with Experimental Modal Analysis (United States)


    simulations of structural response.8 In the experiments, stereo- digital image correlation (SDIC) was used to record the shock response of a V-hull structure...and the associated fast Fourier transforms corroborate this statement.9 Therefore, the first mode is considered the most important metric for... Organisation , Aeronautical and Maritime Research Laboratory; 2001 June. Report No.: DSTO-TR-1168. 7. Cummins C. Modeling brown clayey sand in LS-DYNA

  18. Weight optimization of offshore supply vessel based on structural analysis using finite element meth

    Directory of Open Access Journals (Sweden)

    Ahmed M.H. Elhewy


    Full Text Available Ship design process usually relies on statistics and comparisons with existing ships, rather than analytical approaches and optimization techniques. Designers found this way as the best to fulfil the owner’s requirements, but better solutions, for both the shipyard and the owner may exist. Assessing ship life cycle cost is one of the most attractive tasks for shipyard during early design stage. Structural optimization can be used to achieve that task. In this paper, a comprehensive study on the structural optimization of an offshore supply vessel (OSV, as a case study, is presented. Detailed structural modeling of the vessel is created. Various environmental loads acting on the ship hull such as still water loads and wave induced loads are briefly explained. Different loading conditions and corresponding structural responses have been investigated to assign the most severe one on the vessel. The basic concept of structural optimization and optimization characteristics is highlighted. Blind search optimization technique is applied and approximately forty-two percent weight and cost savings are found by comparing the weight of various design scenarios together without showing any structural inadequacy.

  19. Prediction of transmission, reflection and absorption coefficients of periodic structures using a hybrid Wave Based - Finite Element unit cell method (United States)

    Deckers, Elke; Jonckheere, Stijn; Van Belle, Lucas; Claeys, Claus; Desmet, Wim


    This paper presents a hybrid Wave Based Method - Finite Element unit cell method to predict the absorption, reflection and transmission properties of arbitrary, two-dimensional periodic structures. The planar periodic structure, represented by its unit cell combined with Bloch-Floquet periodicity boundary conditions, is modelled within the Finite Element Method, allowing to represent complex geometries and to include any type of physics. The planar periodic structure is coupled to semi-infinite acoustic domains above and/or below, in which the dynamic pressure field is modelled with the Wave Based Method, applying a wave function set that fulfills the Helmholtz equation and satisfies the Sommerfeld radiation condition and the Bloch-Floquet periodicity conditions inherently. The dynamic fields described within both frameworks are coupled using a direct coupling strategy, accounting for the mutual dynamic interactions via a weighted residual formulation. The method explicitly accounts for the interaction between the unit cell and the surrounding acoustic domain, also accounting for higher order periodic waves. The convergence of the method is analysed and its applicability is shown for a variety of problems, proving it to be a useful tool combining the strengths of two methods.

  20. Monoacyl phosphatidylcholine inhibits the formation of lipid multilamellar structures during in vitro lipolysis of self-emulsifying drug delivery systems

    DEFF Research Database (Denmark)

    Tran, Thuy; Siqueira, Scheyla D V S; Amenitsch, Heinz


    The colloidal structures formed during lipolysis of self-emulsifying drug delivery systems (SEDDS) might affect the solubilisation and possibly the absorption of drugs. The aim of the current study is to elucidate the structures formed during the in vitro lipolysis of four SEDDS containing medium......-chain glycerides and caprylocaproyl polyoxyl-8 glycerides (Labrasol), with or without monoacyl phosphatidylcholine (MAPC). In situ synchrotron small-angle X-ray scattering (SAXS) was combined with ex situ cryogenic transmission electron microscopy (cryo-TEM) and dynamic light scattering (DLS) to elucidate...... the generated structures. The SAXS scattering curves obtained during the lipolysis of MAPC-free SEDDS containing 43-60% w/w Labrasol displayed a lamellar phase peak at q=2.13nm(-1) that increased with Labrasol concentration, suggesting the presence of multilamellar structures (MLS) with a d-spacing of 2.95nm...

  1. Crystal structure of the GTPase domain and the bundle signalling element of dynamin in the GDP state

    Energy Technology Data Exchange (ETDEWEB)

    Anand, Roopsee; Eschenburg, Susanne; Reubold, Thomas F., E-mail:


    Dynamin is the prototype of a family of large multi-domain GTPases. The 100 kDa protein is a key player in clathrin-mediated endocytosis, where it cleaves off vesicles from membranes using the energy from GTP hydrolysis. We have solved the high resolution crystal structure of a fusion protein of the GTPase domain and the bundle signalling element (BSE) of dynamin 1 liganded with GDP. The structure provides a hitherto missing snapshot of the GDP state of the hydrolytic cycle of dynamin and reveals how the switch I region moves away from the active site after GTP hydrolysis and release of inorganic phosphate. Comparing our structure of the GDP state with the known structures of the GTP state, the transition state and the nucleotide-free state of dynamin 1 we describe the structural changes through the hydrolytic cycle. - Highlights: • High resolution crystal structure of the GDP-state of a dynamin 1 GTPase-BSE fusion. • Visualizes one of the key states of the hydrolytic cycle of dynamin. • The dynamin-specific loop forms a helix as soon as a guanine base is present.

  2. Combining the Finite Element Method with Structural Connectome-based Analysis for Modeling Neurotrauma: Connectome Neurotrauma Mechanics (United States)

    Kraft, Reuben H.; Mckee, Phillip Justin; Dagro, Amy M.; Grafton, Scott T.


    This article presents the integration of brain injury biomechanics and graph theoretical analysis of neuronal connections, or connectomics, to form a neurocomputational model that captures spatiotemporal characteristics of trauma. We relate localized mechanical brain damage predicted from biofidelic finite element simulations of the human head subjected to impact with degradation in the structural connectome for a single individual. The finite element model incorporates various length scales into the full head simulations by including anisotropic constitutive laws informed by diffusion tensor imaging. Coupling between the finite element analysis and network-based tools is established through experimentally-based cellular injury thresholds for white matter regions. Once edges are degraded, graph theoretical measures are computed on the “damaged” network. For a frontal impact, the simulations predict that the temporal and occipital regions undergo the most axonal strain and strain rate at short times (less than 24 hrs), which leads to cellular death initiation, which results in damage that shows dependence on angle of impact and underlying microstructure of brain tissue. The monotonic cellular death relationships predict a spatiotemporal change of structural damage. Interestingly, at 96 hrs post-impact, computations predict no network nodes were completely disconnected from the network, despite significant damage to network edges. At early times () network measures of global and local efficiency were degraded little; however, as time increased to 96 hrs the network properties were significantly reduced. In the future, this computational framework could help inform functional networks from physics-based structural brain biomechanics to obtain not only a biomechanics-based understanding of injury, but also neurophysiological insight. PMID:22915997

  3. The Guidelines for Modelling the Preloading Bolts in the Structural Connection Using Finite Element Methods

    Directory of Open Access Journals (Sweden)

    Paulina Krolo


    Full Text Available The aim of this paper is the development of the two different numerical techniques for the preloading of bolts by the finite element method using the software Abaqus Standard. Furthermore, this paper gave detailed guidelines for modelling contact, method for solving the numerical error problems such as numerical singularity error and negative eigenvalues due to rigid body motion or the problem of the extensive elongation of bolts after pretension which is occurring during the analysis. The behaviour of bolted joints depending on the two different approaches of pretension was shown on the example of an extended end-plate bolted beam-to-column connection under the monotonic loading. The behaviour of beam-to-column connection was shown in the form and moment-rotation (M-ϕ curves and validated by experimental test. Advantages and disadvantages of pretension techniques, as well as the speed of numerical models, were also presented in this paper.

  4. Homoserine Lactone as a Structural Key Element for the Synthesis of Multifunctional Polymers

    Directory of Open Access Journals (Sweden)

    Fabian Marquardt


    Full Text Available The use of bio-based building blocks for polymer synthesis represents a milestone on the way to “green” materials. In this work, two synthetic strategies for the preparation of multifunctional polymers are presented in which the key element is the functionality of homoserine lactone. First, the synthesis of a bis cyclic coupler based on a thiolactone and homoserine lactone is displayed. This coupler was evaluated regarding its regioselectivity upon reaction with amines and used in the preparation of multifunctional polymeric building blocks by reaction with diamines. Furthermore, a linear polyglycidol was functionalized with homoserine lactone. The resulting polyethers with lactone groups in the side chain were converted to cationic polymers by reaction with 3-(dimethylamino-1-propylamine followed by quaternization with methyl iodide.

  5. Structural characterisation and transdermal delivery studies on sugar microneedles: experimental and finite element modelling analyses. (United States)

    Loizidou, Eriketi Z; Williams, Nicholas A; Barrow, David A; Eaton, Mark J; McCrory, John; Evans, Sam L; Allender, Chris J


    Dissolving microneedles are especially attractive for transdermal drug delivery as they are associated with improved patient compliance and safety. Furthermore, microneedles made of sugars offer the added benefit of biomolecule stabilisation making them ideal candidates for delivering biological agents such as proteins, peptides and nucleic acids. In this study, we performed experimental and finite element analyses to study the mechanical properties of sugar microneedles and evaluate the effect of sugar composition on microneedle ability to penetrate and deliver drug to the skin. Results showed that microneedles made of carboxymethylcellulose/maltose are superior to those made of carboxymethylcellulose/trehalose and carboxymethylcellulose/sucrose in terms of mechanical strength and the ability to deliver drug. Buckling was predicted to be the main mode of microneedle failure and the order of buckling was positively correlated to the Young's modulus values of the sugar constituents of each microneedle. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. ‘Censorable’ Structures in W. S. Maugham's Novels- Linguistic and Cultural Elements

    Directory of Open Access Journals (Sweden)

    Ana-Maria PÂCLEANU


    Full Text Available Communist censorship stigmatised the Romanian cultural life in general, literature in particular. Rejecting and banning anything related to fascism, mysticism, chauvinism, religion, anything demoralising or sentimental, confusion causing or hostile to the regime was common practice. W. S. Maugham’s novels contain many of the historic, cultural and social elements the regime intended to keep people away from. Therefore, some of the translations of his novels (into Romanian were banned and other versions were published later. The Razor’s Edge and The Painted Veil are two of the censored novels and the present paper deals with these aforementioned aspects from the linguistic point of view, by considering also the translation issues.

  7. Effect of Stochastics of Dimensional Parameters of Hauling Laminated Bushless Chain Elements of Improved Structure on Their Bearing Strength

    Directory of Open Access Journals (Sweden)

    Kryvyi Petro


    Full Text Available The distribution densities of dimensional parameters of a hauling laminated bushless chain of improved structure were investigated in this paper. The authors suggest calculating the non-uniform load of internal and external links plates by probability coefcient Km, for which the minimum, the most probable and the maximum values were determined. The formula for Km determination depending on plate size variety due to a gap random value Δ and plate elastic deformation value under permitted payload was obtained. The efect of stochastics of dimensional parameters of hauling laminated bushless chain elements on their bearing strength is proved.

  8. Novel Structure of Enterococcus faecium-Originated ermB-Positive Tn1546-Like Element in Staphylococcus aureus. (United States)

    Wan, Tsai-Wen; Hung, Wei-Chun; Tsai, Jui-Chang; Lin, Yu-Tzu; Lee, Hao; Hsueh, Po-Ren; Lee, Tai-Fen; Teng, Lee-Jene


    We determined the resistance determinants in 274 erythromycin-resistant methicillin-susceptible Staphylococcus aureus (MSSA) isolates during a 13-year period, 2000 to 2012. The resistance phenotypes, inducible macrolide-lincosamide-streptogramin (iMLS), constitutive MLS (cMLS), and macrolide-streptogramin (MS) resistance phenotypes, were examined by a double-disk diffusion D test. The ermB gene was more frequent (35%; 97/274) than ermC (27%; 75/274) or ermA (21%; 58/274). All 97 ermB-positive isolates harbored Tn551 and IS1216V The majority (89/97) of ermB-positive isolates displayed the cMLS phenotype and carried mobile element structure (MES)-like structures, which has been previously reported in sequence type 59 (ST59) methicillin-resistant S. aureus (MRSA). The remaining 8 ermB-carrying isolates, belonging to ST7 (n = 4), ST5 (n = 3), and ST59 (n = 1), were sasK intact and did not carry MES-like structures. Unlike a MES-like structure that was located on the chromosome, the ermB elements on sasK-intact isolates were located on plasmids by S1 nuclease pulsed-field gel electrophoresis (PFGE) analysis and conjugation tests. Sequence data for the ermB-containing region (14,566 bp) from ST59 NTUH_3874 revealed that the best match was a Tn1546-like element in plasmid pMCCL2 DNA (GenBank accession number AP009486) of Macrococcus caseolyticus Tn1546 is recognized as an enterococcal transposon and was known from the vancomycin resistance gene cluster in vancomycin-resistant Enterococcus (VRE). So far, acquisitions of Tn1546 in S. aureus have occurred in clonal complex 5 (CC5) MRSA, but not in MSSA. This is the first report that MSSA harbors an Enterococcus faecium-originated ermB-positive Tn1546-like element located on a plasmid. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  9. Synthesis and Structure of a Ternary Copper(II) Complex with Mixed Ligands of Diethylenetriamine and Picrate: DNA/Protein-Binding Property and In Vitro Anticancer Activity Studies. (United States)

    Shi, Ya-Ning; Zheng, Kang; Zhu, Ling; Li, Yan-Tuan; Wu, Zhi-Yong; Yan, Cui-Wei


    Based on the importance of the design and synthesis of transition metal complexes with noncovalent DNA/protein-binding abilities in the field of metallo pharmaceuticals, a new mononuclear ternary copper(II) complex with mixed ligands of diethylenetriamine (dien) and picrate anion (pic), identified as [Cu(dien)(pic)](pic), was synthesized and characterized by elemental analysis, molar conductivity measurement, infrared spectrum, electronic spectral studies, and single-crystal X-ray diffractometry. The structure analysis reveals that the copper(II) complex crystallizes in the monoclinic space group P21 /c, and the copper(II) ion has a distorted square pyramidal coordination geometry. A two-dimensional supramolecular structure is formed through hydrogen bonds. The DNA/bovine serum albumin (BSA)-binding properties of the complex are explored, indicating that the complex can interact with herring sperm DNA via intercalation mode and bind to BSA responsible for quenching of tryptophan fluorescence by static quenching mechanism. The in vitro anticancer activity shows that the copper(II) complex is active against the selected tumor cell lines. © 2015 Wiley Periodicals, Inc.

  10. The Use of the STAGS Finite Element Code in Stitched Structures Development (United States)

    Jegley, Dawn C.; Lovejoy, Andrew E.


    In the last 30 years NASA has worked in collaboration with industry to develop enabling technologies needed to make aircraft more fuel-efficient and more affordable. The focus on the airframe has been to reduce weight, improve damage tolerance and better understand structural behavior under realistic flight and ground loading conditions. Stitched structure is a technology that can address the weight savings, cost reduction, and damage tolerance goals, but only if it is supported by accurate analytical techniques. Development of stitched technology began in the 1990's as a partnership between NASA and Boeing (McDonnell Douglas at the time) under the Advanced Composites Technology Program and has continued under various titles and programs and into the Environmentally Responsible Aviation Project today. These programs contained development efforts involving manufacturing development, design, detailed analysis, and testing. Each phase of development, from coupons to large aircraft components was supported by detailed analysis to prove that the behavior of these structures was well-understood and predictable. The Structural Analysis of General Shells (STAGS) computer code was a critical tool used in the development of many stitched structures. As a key developer of STAGS, Charles Rankin's contribution to the programs was quite significant. Key features of STAGS used in these analyses and discussed in this paper include its accurate nonlinear and post-buckling capabilities, its ability to predict damage growth, and the use of Lagrange constraints and follower forces.

  11. Non-linear finite element analysis for prediction of seismic response of buildings considering soil-structure interaction

    Directory of Open Access Journals (Sweden)

    E. Çelebi


    Full Text Available The objective of this paper focuses primarily on the numerical approach based on two-dimensional (2-D finite element method for analysis of the seismic response of infinite soil-structure interaction (SSI system. This study is performed by a series of different scenarios that involved comprehensive parametric analyses including the effects of realistic material properties of the underlying soil on the structural response quantities. Viscous artificial boundaries, simulating the process of wave transmission along the truncated interface of the semi-infinite space, are adopted in the non-linear finite element formulation in the time domain along with Newmark's integration. The slenderness ratio of the superstructure and the local soil conditions as well as the characteristics of input excitations are important parameters for the numerical simulation in this research. The mechanical behavior of the underlying soil medium considered in this prediction model is simulated by an undrained elasto-plastic Mohr-Coulomb model under plane-strain conditions. To emphasize the important findings of this type of problems to civil engineers, systematic calculations with different controlling parameters are accomplished to evaluate directly the structural response of the vibrating soil-structure system. When the underlying soil becomes stiffer, the frequency content of the seismic motion has a major role in altering the seismic response. The sudden increase of the dynamic response is more pronounced for resonance case, when the frequency content of the seismic ground motion is close to that of the SSI system. The SSI effects under different seismic inputs are different for all considered soil conditions and structural types.

  12. Finite Element Structural Analysis of a Low Energy Micro Sheet Forming Machine Concept Design (United States)

    Razali, A. R.; Ann, C. T.; Ahmad, A. F.; Shariff, H. M.; Kasim, N. I.; Musa, M. A.


    It is forecasted that with the miniaturization of materials being processed, energy consumption will also be ‘miniaturized’ proportionally. The aim of this researchis to design a low energy micro-sheet-forming machine for the application of thin sheet metal. A fewconcept designsof machine structure were produced. With the help of FE software, the structure is then subjected to a forming force to observe deflection in the structure for the selection of the best and simplest design. Comparison studies between mild steel and aluminium alloys 6061 were made with a view to examine the most suitable material to be used. Based on the analysis, allowable maximum tolerance was set at 2.5µm and it was found that aluminium alloy 6061 suffice to be used.

  13. Output-only identification of civil structures using nonlinear finite element model updating (United States)

    Ebrahimian, Hamed; Astroza, Rodrigo; Conte, Joel P.


    This paper presents a novel approach for output-only nonlinear system identification of structures using data recorded during earthquake events. In this approach, state-of-the-art nonlinear structural FE modeling and analysis techniques are combined with Bayesian Inference method to estimate (i) time-invariant parameters governing the nonlinear hysteretic material constitutive models used in the FE model of the structure, and (ii) the time history of the earthquake ground motion. To validate the performance of the proposed framework, the simulated responses of a bridge pier to an earthquake ground motion is polluted with artificial output measurement noise and used to jointly estimate the unknown material parameters and the time history of the earthquake ground motion. This proof-of-concept example illustrates the successful performance of the proposed approach even in the presence of high measurement noise.

  14. Damage Characterization Using the Extended Finite Element Method for Structural Health Management (United States)

    Krishnamurthy, Thiagarajan; Gallegos, Adam M.


    The development of validated multidisciplinary Integrated Vehicle Health Management (IVHM) tools, technologies, and techniques to enable detection, diagnosis, prognosis, and mitigation in the presence of adverse conditions during flight will provide effective solutions to deal with safety related challenges facing next generation aircraft. The adverse conditions include loss of control caused by environmental factors, actuator and sensor faults or failures, and damage conditions. A major concern in these structures is the growth of undetected damage/cracks due to fatigue and low velocity foreign impact that can reach a critical size during flight, resulting in loss of control of the aircraft. Hence, development of efficient methodologies to determine the presence, location, and severity of damage/cracks in critical structural components is highly important in developing efficient structural health management systems.

  15. Elemental changes in hemolymph and urine of Rhodnius prolixus induced by in-vitro exposure to mercury: A study using SR-TXRF

    Energy Technology Data Exchange (ETDEWEB)

    Mantuano, Andrea; Barroso, Regina C. [Physics Institute/State University of Rio de Janeiro (UERJ), RJ (Brazil); Almeida, Andre P. de; Braz, Delson [Nuclear Engineering Program/COPPE/Federal University of Rio de Janeiro, RJ (Brazil); Cardoso, Simone C. [Physics Institute/Federal University of Rio de Janeiro, RJ (Brazil); Penna, Patricia A.; Gonzalez, Marcelo S. [Laboratory of Biochemistry and Physiology of Insects/Oswaldo Cruz Foundation (FIOCRUZ), Rio de Janeiro, RJ (Brazil)


    Full text: In the last years have been studied the effects of the pollution of humans and others vertebrates, however, the effects on invertebrates are poorly knows. Some pollutants introduced in aquatic and terrestrial ecosystems are potentially toxic to living organisms. Almost the environmental pollutants, the heavy metals are not degradable and can persist during long time of many ecosystems causing ecologic changes often disastrous to species that habit there. Actually some works has shown that the heavy metals beyond be toxic and interfere on development and reproduction of some species of terrestrial and marine invertebrates. When are present in cells, the chemical form and connection type of metals are critical factors that determinate the toxicity. So, the ambient pollution has chronic effects and acute of animals health and can affect any systems and organs. The intoxications that current often are caused by aluminum, arsenic, barium, beryllium, cadmium, lead, mercury and nickel. Know that these elements can change cellular structures, enzymes and replace metal cofactors in enzyme activities. In insects, the effects of pollution change according to specie studied. The pollution can act on the weight reduction and increasing the relative growth rate. In this work, we investigated the effect of mercury exposure on the elemental content in hemolymph and urine of Rhodnius prolixus the insect vector of Chagas' disease, which is one of the most important vectors in Latin American and also, the most well-know studied insect in terms of both physiology and vector-parasite interactions. Five-stage nymphs of Rhodnius prolixus were collected from colony of a Laboratory Physiology and Biochemistry of Insects, Institute Oswaldo Cruz RJ. For treatment of insects, mercury chloride has been added to rabbit blood. After feeding the nymphs were separated and packed for two days for collection of hemolymph and urine. The SR-TXRF measurements were performed at the X

  16. In vitro germination and structure of hard seed testa of natural ...

    African Journals Online (AJOL)



    Mar 3, 2008 ... Sterilization and culture conditions. To germinate the seeds in vitro, seeds were first sterilized in 96% ethanol for 1 min and then transferred to 10% sodium hypochlorite solution for 10 min (commercial sodium hypochlorite was used in sterilization process). Then seeds were rinsed 3 times in sterilized water.

  17. GISAXS/GIXRD View of ZnO Films with Hierarchical Structural Elements

    Directory of Open Access Journals (Sweden)

    M. Lučić Lavčević


    Full Text Available ZnO films constituted of porous sheet-like structures, formed by calcination of precursor, were examined using scanning electron microscopy and simultaneous small-angle scattering and diffraction of the synchrotron-sourced X-rays, under the grazing-incidence conditions. The presented analysis enabled insight into the complexity of the film morphology, which revealed substrate sensitivity on the microscopic and nanoscopic length scales. The average size and spatial arrangement of nanoparticles, single-crystal domains, and the average size and features of nanopores in sheet-like structures were determined for films deposited on glass, polycrystalline ZnO layer, and silicon.

  18. Least-Squares Finite Element Formulation for Fluid-Structure Interaction (United States)


    derivative, e.g., At @u @t + A1 @u @x + A2 @u @y + A0u = At @u @t + Asu = f (3.86) and equations that do not contain a time derivative, e.g., A1 @u @x + A2...u @y + A0u = Asu = f (3.87) Equation (3.86) is discretized with the -method for those equations with a time derivative via At un+1 un t + Asun+1...AHS/ASC Structures, Structural Dynamics, and Materials Conference, April 1994. 21. G. Guruswamy, �A new modular approach for tightly coupled �uid

  19. Characteristics of sandwich-type structural elements built of advanced composite materials from three dimensional fabrics

    Directory of Open Access Journals (Sweden)

    Castejón, L.


    Full Text Available Sandwich-type structures have proved to be alternatives of great success for several fields of application, and specially in the building sector. This is due to their outstanding properties of .specific rigidity and strength against bending loads and other range of advantages like fatigue and impact resistance, attainment of flat and smooth surfaces, high electric and thermal insulation, design versatility and some others. However, traditional sandwich structures present problems like their tendency towards delamination, stress concentrations in bores or screwed Joints, and pre resistance. These problems are alleviated thanks to the use of new sandwich structures built using three dimensional structures of advanced composite materials, maintaining the present advantages for more traditional sandwich structures. At this rate, these new structures can be applied in several areas where conventional sandwich structures used to be like walls, partitions, floor and ceiling structures, domes, vaults and dwellings, but with greater success.

    Las estructuras tipo sándwich han demostrado ser alternativas de gran éxito para diversos campos de aplicación y, en concreto, en el sector de la construcción, listo es gracias a sus excelentes propiedades de rigidez y resistencia específica frente a cargas de flexión y otra larga lista de ventajas, a la que pertenecen, por ejemplo, su buena resistencia a fatiga, resistencia al impacto, obtención de superficies lisas y suaves, elevado aislamiento térmico y eléctrico, versatilidad de diseño y otras. Sin embargo, las estructuras sándwich, tradicionales presentan una problemática consistente en su tendencia a la delaminación, concentraciones de tensiones ¿aparecidas ante la existencia de agujeros o uniones atornilladas y resistencia al fuego. Estos problemas son pifiados gracias a la aplicación de estructuras novedosas tipo sándwich, construidas a partir de tejidos tridimensionales de materiales

  20. MxaJ structure reveals a periplasmic binding protein-like architecture with unique secondary structural elements. (United States)

    Myung Choi, Jin; Cao, Thinh-Phat; Wouk Kim, Si; Ho Lee, Kun; Haeng Lee, Sung


    MxaJ is a component of type II methanol dehydrogenase (MDH) that mediates electron transfer during methanol oxidation in methanotrophic bacteria. However, little is known about how MxaJ structurally cooperates with MDH and Cytochrome c L . Here, we report for the first time the crystal structure of MxaJ. MxaJ consists of eight α-helices and six β-strands, and resembles the "bi-lobate" folding architecture found in periplasmic binding proteins. Distinctive features of MxaJ include prominent loops and a β-strand around the hinge region supporting the ligand-binding cavity, which might provide a more favorable framework for interacting with proteins rather than small molecules. Proteins 2017; 85:1379-1386. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.