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Sample records for building cloaking structures

  1. A Phase-Conjugate-Mirror Inspired Approach for Building Cloaking Structures with Left-handed Materials.

    Science.gov (United States)

    Zheng, Guoan; Heng, Xin; Yang, Changhuei

    2009-01-01

    A phase conjugate mirror (PCM) has a remarkable property of cancellation the back-scattering wave of the lossless scatterers. The similarity of a phase conjugate mirror to the interface of a matched RHM (right-handed material) and a LHM (left-handed material) prompts us to explore the potentials of using the RHM-LHM structure to achieve the anti-scattering property of the PCM. In this paper, we present two such structures. The first one is a RHM-LHM cloaking structure with a lossless arbitrary-shape scatterer imbedded in the RHM and its left-handed duplicate imbedded in the matched LHM. It is shown that such a structure is transparent to the incident electromagnetic (EM) field. As a special case of this structure, we proposed an EM tunnel that allows EM waves to spatially transport to another location in space without significant distortion and reflection. The second one is an RHM-PEC (perfect electric conductor)-LHM cloaking structure, which is composed of a symmetric conducting shell embedded in the interface junction of an RHM and the matched LHM layer. Such a structure presents an anomalously small scattering cross-section to an incident propagating EM field, and the interior of the shell can be used to shield small objects (size comparable to the wavelength) from interrogation. We report the results of 2D finite-element-method (FEM) simulations that were performed to verify our idea, and discuss the unique properties of the proposed structures as well as their limitations.

  2. Design of elliptic cylindrical thermal cloak with layered structure

    Science.gov (United States)

    Yuan, Xuebo; Lin, Guochang; Wang, Youshan

    2017-01-01

    Thermal cloak has potential applications in thermal protection and sensing. Based on the theories of spatial transformation and effective medium, layered structure of elliptic cylindrical thermal cloak was designed. According to theoretical analysis and numerical simulation, the layered structure has typical characteristics of perfect thermal cloak. The external temperature field remains unchanged, while the internal temperature gradient decreases obviously. Meanwhile, the cloaking effect is stable in any direction. The cloaking effect can be improved by increasing the number of discretization layers or reducing the cloak thickness. The elliptic cylindrical cloak can be considered as cylindrical cloak when the focal distance is close to zero. This study has provided an effective way for realizing thermal cloak with more complex shapes.

  3. Making waves round a structured cloak: lattices, negative refraction and fringes.

    Science.gov (United States)

    Colquitt, D J; Jones, I S; Movchan, N V; Movchan, A B; Brun, M; McPhedran, R C

    2013-09-01

    Using the framework of transformation optics, this paper presents a detailed analysis of a non-singular square cloak for acoustic, out-of-plane shear elastic and electromagnetic waves. Analysis of wave propagation through the cloak is presented and accompanied by numerical illustrations. The efficacy of the regularized cloak is demonstrated and an objective numerical measure of the quality of the cloaking effect is provided. It is demonstrated that the cloaking effect persists over a wide range of frequencies. As a demonstration of the effectiveness of the regularized cloak, a Young's double slit experiment is presented. The stability of the interference pattern is examined when a cloaked and uncloaked obstacle are successively placed in front of one of the apertures. This novel link with a well-known quantum mechanical experiment provides an additional method through which the quality of cloaks may be examined. In the second half of the paper, it is shown that an approximate cloak may be constructed using a discrete lattice structure. The efficiency of the approximate lattice cloak is analysed and a series of illustrative simulations presented. It is demonstrated that effective cloaking may be obtained by using a relatively simple lattice structure, particularly, in the low-frequency regime.

  4. Metamaterial Structure Design Optimization: A Study of the Cylindrical Cloak

    Science.gov (United States)

    2013-03-01

    energy. iv First, I wish to thank God and my savior, Jesus Christ , for the opportunity to study His creation. Next, a big thank-you goes to my loving wife...requirements to create a more physically realizable set of material parameters. 6 2.1 TO Cylindrical Cloak Originally , TO was conceived in an effort to avoid...TO method to designing a cloak consists of deforming the coordinate system such that the origin point is expanded into a boundary around an area to be

  5. Making Waves Round a Structured Cloak: Lattices, Negative Refraction and Fringes

    CERN Document Server

    Colquitt, DJ; Movchan, NV; Brun, AB Movchan M; McPhedran, RC

    2013-01-01

    Using the framework of transformation optics, this paper presents a detailed analysis of a non-singular square cloak for acoustic, out-of-plane shear elastic, and electromagnetic waves. The generating map is examined in detail and linked to the material properties of the cloak. Analysis of wave propagation through the cloak is presented and accompanied by numerical illustrations. The efficacy of the regularised cloak is demonstrated and an objective numerical measure of the quality of the cloaking effect is provided. It is demonstrated that the cloaking effect persists over a wide range of frequencies. As a demonstration of the effectiveness of the regularised cloak, a Young's double slit experiment is presented. The stability of the interference pattern is examined when a cloaked and uncloaked obstacle are successively placed in front of one of the apertures. This novel link with a well-known quantum mechanical experiment provides an additional method through which the quality of cloaks may be examined. In t...

  6. Impact of Radii Ratios on a Two-Dimensional Cloaking Structure and Corresponding Analysis for Practical Design at Optical Wavelengths

    Directory of Open Access Journals (Sweden)

    Nadia Anam

    2017-01-01

    Full Text Available This work is an extension to the evaluation and analysis of a two-dimensional cylindrical cloak in the Terahertz or visible range spectrum using Finite Difference Time-Domain (FDTD method. It was concluded that it is possible to expand the frequency range of a cylindrical cloaking model by careful scaling of the inner and outer radius of the simulation geometry with respect to cell size and/or number of time steps in the simulation grid while maintaining appropriate stability conditions. Analysis in this study is based on a change in the radii ratio, that is, outer radius to inner radius, of the cloaking structure for an array of wavelengths in the visible spectrum. Corresponding outputs show inconsistency in the cloaking pattern with respect to frequency. The inconsistency is further increased as the radii ratio is decreased. The results also help to establish a linear relationship between the transmission coefficient and the real component of refractive index with respect to different radii ratios which may simplify the selection of the material for practical design purposes. Additional performance analysis is carried out such that the dimensions of the cloak are held constant at an average value and the frequency varied to determine how a cloaked object may be perceived by the human eye which considers different wavelengths to be superimposed on each other simultaneously.

  7. Bistatic scattering characterization of a three-dimensional broadband cloaking structure

    CERN Document Server

    Alitalo, Pekka; Osipov, Andrey V; Thurner, Stefan; Kemptner, Erich; Tretyakov, Sergei A

    2011-01-01

    Here we present the results of full experimental characterization of broadband cloaking of a finite-sized metallic cylinder at X-band. The cloaking effect is characterized by measuring the bistatic scattering patterns of uncloaked and cloaked objects in free space and then comparing these with each other. The results of the measurements demonstrate a broadband cloaking effect and are in good agreement with numerical predictions.

  8. Transformation optics and invisibility cloaks

    DEFF Research Database (Denmark)

    Qiu, Min; Yan, Min; Yan, Wei

    2008-01-01

    In this paper, we briefly summarize the theory of transformation optics and introduce its application in achieving perfect invisibility cloaking. In particular, we theoretically show how the task of realizing cylindrical invisibility cloaks can be eased by using either structural approximation...

  9. Electromagnetic Invisibility of Elliptic Cylinder Cloaks

    Institute of Scientific and Technical Information of China (English)

    YAO Kan; LI Chao; LI Fang

    2008-01-01

    Structures with unique electromagnetic properties are designed based on the approach of spatial coordinate transformations of Maxwell's equations.This approach is applied to scheme out invisible elliptic cylinder cloaks,which provide more feasibility for cloaking arbitrarily shaped objects.The transformation expressions for the anisotropic material parameters and the field distribution are derived.The cloaking performances of ideal and lossy elliptic cylinder cloaks are investigated by finite element simulations. It is found that the cloaking performance will degrade in the forward direction with increasing loss.

  10. Dielectric optical invisibility cloaks

    Science.gov (United States)

    Blair, J.; Tamma, V. A.; Park, W.; Summers, C. J.

    2010-08-01

    Recently, metamaterial cloaks for the microwave frequency range have been designed using transformative optics design techniques and experimentally demonstrated. The design of these structures requires extreme values of permittivity and permeability within the device, which has been accomplished by the use of resonating metal elements. However, these elements severely limit the operating frequency range of the cloak due to their non-ideal dispersion properties at optical frequencies. In this paper we present designs to implement a simpler demonstration of cloaking, the carpet cloak, in which a curved reflective surface is compressed into a flat reflective surface, effectively shielding objects behind the curve from view with respect to the incoming radiation source. This approach eliminates the need for metallic resonant elements. These structures can now be fabricated using only high index dielectric materials by the use of electron beam lithography and standard cleanroom technologies. The design method, simulation analysis, device fabrication, and near field optical microscopy (NSOM) characterization results are presented for devices designed to operate in the 1400-1600nm wavelength range. Improvements to device performance by the deposition/infiltration of linear, and potentially non-linear optical materials, were investigated.

  11. Practical Invisibility Cloaking

    Science.gov (United States)

    Choi, Joseph Sung-hwoon

    This thesis presents mainly two methodologies for achieving practical invisibility cloaking. Thus, using commercial technologies, devices that are good approximations to an 'ideal' cloak can be achieved - a cloak that is omnidirectional, broadband, operational for the visible spectrum, three-dimensional (3D), and phase-matching for the light field, among other attributes. We first describe 'paraxial cloaking,' where cloaking is considered as an imaging system. The small-angle ('paraxial') formalism provides a first-order design requirement for any 'perfect' cloaking device. A ray optics four-lens cloak (called the "Rochester Cloak'") is experimentally demonstrated, followed by theoretical work to match the phase for the entire visible spectrum. To extend our broadband, paraxial cloak to larger viewing angles, we then discretize space, angle, spectrum, and phase to approximate an ideal, omnidirectional cloak. Such 'discretized cloaking' is experimentally demonstrated as a 'digital cloak,' where commercially available digital image capture and display technologies are used. In particular, we demonstrate an active cloak that uses lenticular lenslet arrays, similar to 'integral imaging' for 3D displays. The 'digital integral cloak' we demonstrate is dynamic, but requires a time delay for image capture and processing, and is two-dimensional (2D) without phase-matching. Continuing improvements in commercial digital technology and computational power will minimize the resolution limitations of a digital cloak and enhance its processing speed. Thus, a wearable cloak can then be practically realized in the future.

  12. Paraxial Ray Optics Cloaking

    CERN Document Server

    Choi, Joseph S

    2014-01-01

    Despite much interest and progress in optical spatial cloaking, a three-dimensional (3D), transmitting, continuously multidirectional cloak in the visible regime has not yet been demonstrated. Here we experimentally demonstrate such a cloak using ray optics, albeit with some edge effects. Our device requires no new materials, uses isotropic off-the-shelf optics, scales easily to cloak arbitrarily large objects, and is as broadband as the choice of optical material, all of which have been challenges for current cloaking schemes. In addition, we provide a concise formalism that quantifies and produces perfect optical cloaks in the small-angle (`paraxial') limit, and must be satisfied by any good cloaks.

  13. Topology optimized cloak for airborne sound

    DEFF Research Database (Denmark)

    Andkjær, Jacob Anders; Sigmund, Ole

    2013-01-01

    Directional acoustic cloaks that conceal an aluminum cylinder for airborne sound waves are presented in this paper. Subwavelength cylindrical aluminum inclusions in air constitute the cloak design to aid practical realizations. The positions and radii of the subwavelength cylinders are determined...... by minimizing scattering from the cloak-structure and cylinder using the gradient-based topology optimization method. In the final optimization step, the radii of the subwavelength cylinders are constrained to three discrete values. A near-perfect narrow-banded and angular cloaking effect is obtained...

  14. Geometry and Cloaking Devices

    Science.gov (United States)

    Ochiai, T.; Nacher, J. C.

    2011-09-01

    Recently, the application of geometry and conformal mappings to artificial materials (metamaterials) has attracted the attention in various research communities. These materials, characterized by a unique man-made structure, have unusual optical properties, which materials found in nature do not exhibit. By applying the geometry and conformal mappings theory to metamaterial science, it may be possible to realize so-called "Harry Potter cloaking device". Although such a device is still in the science fiction realm, several works have shown that by using such metamaterials it may be possible to control the direction of the electromagnetic field at will. We could then make an object hidden inside of a cloaking device. Here, we will explain how to design invisibility device using differential geometry and conformal mappings.

  15. Invisibility cloak with image projection capability

    Science.gov (United States)

    Banerjee, Debasish; Ji, Chengang; Iizuka, Hideo

    2016-12-01

    Investigations of invisibility cloaks have been led by rigorous theories and such cloak structures, in general, require extreme material parameters. Consequently, it is challenging to realize them, particularly in the full visible region. Due to the insensitivity of human eyes to the polarization and phase of light, cloaking a large object in the full visible region has been recently realized by a simplified theory. Here, we experimentally demonstrate a device concept where a large object can be concealed in a cloak structure and at the same time any images can be projected through it by utilizing a distinctively different approach; the cloaking via one polarization and the image projection via the other orthogonal polarization. Our device structure consists of commercially available optical components such as polarizers and mirrors, and therefore, provides a significant further step towards practical application scenarios such as transparent devices and see-through displays.

  16. Harry Potter's Cloak

    OpenAIRE

    Zhu, X. F.; Liang, B.; J; Tu; Zhang, D; Cheng, J. C.

    2011-01-01

    The magic "Harry Potter's cloak" has been the dream of human beings for really long time. Recently, transformation optics inspired from the advent of metamaterials offers great versatility for manipulating wave propagation at will to create amazing illusion effects. In the present work, we proposed a novel transformation recipe, in which the cloaking shell somehow behaves like a "cloaking lens", to provide almost all desired features one can expect for a real magic cloak. The most exciting fe...

  17. Optimized cylindrical invisibility cloak with minimum layers of non-magnetic isotropic materials

    Energy Technology Data Exchange (ETDEWEB)

    Yu Zhenzhong; Feng Yijun; Xu Xiaofei; Zhao Junming; Jiang Tian, E-mail: yjfeng@nju.edu.cn [Department of Electronic Engineering, School of Electronic Science and Engineering, Nanjing University, Nanjing, 210093 (China)

    2011-05-11

    We present optimized design of cylindrical invisibility cloak with minimum layers of non-magnetic isotropic materials. Through an optimization procedure based on genetic algorithm, simpler cloak structure and more realizable material parameters can be achieved with better cloak performance than that of an ideal non-magnetic cloak with a reduced set of parameters. We demonstrate that a cloak shell with only five layers of two normal materials can result in an average 20 dB reduction in the scattering width for all directions when covering the inner conducting cylinder with the cloak. The optimized design can substantially simplify the realization of the invisibility cloak, especially in the optical range.

  18. Invisibility Cloak Printed on a Photonic Chip

    CERN Document Server

    Feng, Zhen; Zhao, Yu-Xi; Gao, Jun; Qiao, Lu-Feng; Yang, Ai-Lin; Lin, Xiao-Feng; Jin, Xian-Min

    2016-01-01

    Invisibility cloak capable of hiding an object can be achieved by properly manipulating electromagnetic field. Such a remarkable ability has been shown in transformation and ray optics. Alternatively, it may be realistic to create a spatial cloak by means of confining electromagnetic field in three-dimensional arrayed waveguides and introducing appropriate collective curvature surrounding an object. We realize the artificial structure in borosilicate by femtosecond laser direct writing, where we prototype up to 5000 waveguides to conceal millimeter-scale volume. We characterize the performance of the cloak by normalized cross correlation, tomography analysis and continuous three-dimensional viewing angle scan. Our results show invisibility cloak can be achieved in waveguide optics. Furthermore, directly printed invisibility cloak on a photonic chip may enable controllable study and novel applications in classical and quantum integrated photonics, such as invisualising a coupling or swapping operation with on-...

  19. Invisibility Cloak Printed on a Photonic Chip

    Science.gov (United States)

    Feng, Zhen; Wu, Bing-Hong; Zhao, Yu-Xi; Gao, Jun; Qiao, Lu-Feng; Yang, Ai-Lin; Lin, Xiao-Feng; Jin, Xian-Min

    2016-01-01

    Invisibility cloak capable of hiding an object can be achieved by properly manipulating electromagnetic field. Such a remarkable ability has been shown in transformation and ray optics. Alternatively, it may be realistic to create a spatial cloak by means of confining electromagnetic field in three-dimensional arrayed waveguides and introducing appropriate collective curvature surrounding an object. We realize the artificial structure in borosilicate by femtosecond laser direct writing, where we prototype up to 5,000 waveguides to conceal millimeter-scale volume. We characterize the performance of the cloak by normalized cross correlation, tomography analysis and continuous three-dimensional viewing angle scan. Our results show invisibility cloak can be achieved in waveguide optics. Furthermore, directly printed invisibility cloak on a photonic chip may enable controllable study and novel applications in classical and quantum integrated photonics, such as invisualising a coupling or swapping operation with on-chip circuits of their own. PMID:27329510

  20. Experimental and computational studies of electromagnetic cloaking at microwaves

    Science.gov (United States)

    Wang, Xiaohui

    An invisibility cloak is a device that can hide the target by enclosing it from the incident radiation. This intriguing device has attracted a lot of attention since it was first implemented at a microwave frequency in 2006. However, the problems of existing cloak designs prevent them from being widely applied in practice. In this dissertation, we try to remove or alleviate the three constraints for practical applications imposed by loosy cloaking media, high implementation complexity, and small size of hidden objects compared to the incident wavelength. To facilitate cloaking design and experimental characterization, several devices and relevant techniques for measuring the complex permittivity of dielectric materials at microwave frequencies are developed. In particular, a unique parallel plate waveguide chamber has been set up to automatically map the electromagnetic (EM) field distribution for wave propagation through the resonator arrays and cloaking structures. The total scattering cross section of the cloaking structures was derived based on the measured scattering field by using this apparatus. To overcome the adverse effects of lossy cloaking media, microwave cloaks composed of identical dielectric resonators made of low loss ceramic materials are designed and implemented. The effective permeability dispersion was provided by tailoring dielectric resonator filling fractions. The cloak performances had been verified by full-wave simulation of true multi-resonator structures and experimental measurements of the fabricated prototypes. With the aim to reduce the implementation complexity caused by metamaterials employment for cloaking, we proposed to design 2-D cylindrical cloaks and 3-D spherical cloaks by using multi-layer ordinary dielectric material (epsilon r>1) coating. Genetic algorithm was employed to optimize the dielectric profiles of the cloaking shells to provide the minimum scattering cross sections of the cloaked targets. The designed cloaks can

  1. Elastodynamic cloaking and field enhancement for soft spheres

    Science.gov (United States)

    Diatta, Andre; Guenneau, Sebastien

    2016-11-01

    We propose a spherical cloak described by a non-singular asymmetric elasticity tensor {C} depending upon a small parameter η, that defines the softness of a region one would like to conceal from elastodynamic waves. By varying η, we generate a class of soft spheres dressed by elastodynamic cloaks, which are shown to considerably reduce the scattering of the soft spheres. Importantly, such cloaks also provide some wave protection except for a countable set of frequencies, for which some large elastic field enhancement can be observed within the soft spheres. Through an investigation of trapped modes in elasticity, we supply a good approximation of such Mie-type resonances by some transcendental equation. Our results, unlike previous studies that focused merely on the invisibility aspects, shed light on potential pitfalls of elastodynamic cloaks for earthquake protection designed via geometric transforms: a seismic cloak needs to be designed in such a way that its inner resonances differ from eigenfrequencies of the building one wishes to protect. In order to circumvent this downfall of field enhancement inside the cloaked area, we introduce a novel generation of cloaks, named here, mixed cloaks. Such mixed cloaks consist of a shell that detours incoming waves, hence creating an invisibility region, and of a perfectly matched layer (PML, located at the inner boundary of the cloaks) that absorbs residual wave energy in such a way that aforementioned resonances in the soft sphere are strongly attenuated. The designs of mixed cloaks with a non-singular elasticity tensor combined with an inner PML and non-vanishing density bring seismic cloaks one step closer to a practical implementation. Note in passing that the concept of mixed cloaks also applies in the case of singular cloaks and can be translated in other wave areas for a similar purpose (i.e. to smear down inner resonances within the invisibility region).

  2. Harry Potter's Cloak

    CERN Document Server

    Zhu, X F; Tu, J; Zhang, D; Cheng, J C

    2011-01-01

    The magic "Harry Potter's cloak" has been the dream of human beings for really long time. Recently, transformation optics inspired from the advent of metamaterials offers great versatility for manipulating wave propagation at will to create amazing illusion effects. In the present work, we proposed a novel transformation recipe, in which the cloaking shell somehow behaves like a "cloaking lens", to provide almost all desired features one can expect for a real magic cloak. The most exciting feature of the current recipe is that an object with arbitrary characteristics (e.g., size, shape or material properties) can be invisibilized perfectly with positive-index materials, which significantly benefits the practical realization of a broad-band cloaking device fabricated with existing materials. Moreover, the one concealed in the hidden region is able to undistortedly communicate with the surrounding world, while the lens-like cloaking shell will protect the cloaked source/sensor from being traced back by outside ...

  3. Diffusive-light invisibility cloak for transient illumination

    Science.gov (United States)

    Orazbayev, B.; Beruete, M.; Martínez, A.; García-Meca, C.

    2016-12-01

    Invisibility in a diffusive-light-scattering medium has been recently demonstrated by employing a scattering-cancellation core-shell cloak. Unlike nondiffusive cloaks, such a device can be simultaneously macroscopic, broadband, passive, polarization independent, and omnidirectional. Unfortunately, it has been verified that this cloak, as well as more sophisticated ones based on transformation optics, fail under pulsed illumination, invalidating their use for a variety of applications. Here, we introduce a different approach based on unimodular transformations that enables the construction of unidirectional diffusive-light cloaks exhibiting a perfect invisibility effect, even under transient conditions. Moreover, we demonstrate that a polygonal cloak can extend this functionality to multiple directions with a nearly ideal behavior, while preserving all other features. We propose and numerically verify a simple cloak realization based on a layered stack of two isotropic materials. The studied devices have several applications not addressable by any of the other cloaks proposed to date, including shielding from pulse-based detection techniques, cloaking undesired scattering elements in time-of-flight imaging or high-speed communication systems for diffusive environments, and building extreme optical security features. The discussed cloaking strategy could also be applied to simplify the implementation of thermal cloaks.

  4. Broadband acoustic cloak for ultrasound waves.

    Science.gov (United States)

    Zhang, Shu; Xia, Chunguang; Fang, Nicholas

    2011-01-14

    Invisibility devices based on coordinate transformation have opened up a new field of considerable interest. We present here the first practical realization of a low-loss and broadband acoustic cloak for underwater ultrasound. This metamaterial cloak is constructed with a network of acoustic circuit elements, namely, serial inductors and shunt capacitors. Our experiment clearly shows that the acoustic cloak can effectively bend the ultrasound waves around the hidden object, with reduced scattering and shadow. Because of the nonresonant nature of the building elements, this low-loss (∼6  dB/m) cylindrical cloak exhibits invisibility over a broad frequency range from 52 to 64 kHz. Furthermore, our experimental study indicates that this design approach should be scalable to different acoustic frequencies and offers the possibility for a variety of devices based on coordinate transformation.

  5. Natural Light Cloaking for Aquatic and Terrestrial Creatures

    CERN Document Server

    Chen, Hongsheng; Shen, Lian; Wang, Huaping; Zhang, Xianmin; Zheludev, Nikolay; Zhang, Baile

    2013-01-01

    A cloak that can hide living creatures from sight is a common feature of mythology but still remains unrealized as a practical device. To preserve the phase of wave, the previous cloaking solution proposed by Pendry \\emph{et al.} required transforming electromagnetic space around the hidden object in such a way that the rays bending around it have to travel much faster than those passing it by. The difficult phase preservation requirement is the main obstacle for building a broadband polarization insensitive cloak for large objects. Here, we suggest a simplifying version of Pendry's cloak by abolishing the requirement for phase preservation as irrelevant for observation in incoherent natural light with human eyes that are phase and polarization insensitive. This allows the cloak design to be made in large scale using commonly available materials and we successfully report cloaking living creatures, a cat and a fish, in front of human eyes.

  6. Acoustic elliptical cylindrical cloaks

    Institute of Scientific and Technical Information of China (English)

    Ma Hua; Qu Shao-Bo; Xu Zhuo; Wang Jia-Fu

    2009-01-01

    By making a comparison between the acoustic equations and the 2-dimensional (2D) Maxwell equations, we obtain the material parameter equations (MPE) for acoustic elliptical cylindrical cloaks. Both the theoretical results and the numerical results indicate that an elliptical cylindrical cloak can realize perfect acoustic invisibility when the spatial distributions of mass density and bulk modulus are exactly configured according to the proposed equations. The present work is the meaningful exploration of designing acoustic cloaks that are neither sphere nor circular cylinder in shape, and opens up possibilities for making complex and multiplex acoustic cloaks with simple models such as spheres, circular or elliptic cylinders.

  7. Transformation Optics, Generalized Cloaking and Superlenses

    CERN Document Server

    Nicolet, Andre; Geuzaine, Christophe; 10.1109/TMAG.2010.2043073

    2010-01-01

    In this paper, transformation optics is presented together with a generalization of invisibility cloaking: instead of an empty region of space, an inhomogeneous structure is transformed via Pendry's map in order to give, to any object hidden in the central hole of the cloak, a completely arbitrary appearance. Other illusion devices based on superlenses considered from the point of view of transformation optics are also discussed.

  8. Cloaking an acoustic sensor with single-negative materials

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Chen [Key Laboratory of Modern Acoustics, MOE, Department of Physics, Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093 (China); Zhu, Xue-Feng [Department of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Xu, Tao [Key Laboratory of Modern Acoustics, MOE, Department of Physics, Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093 (China); Zou, Xin-Ye, E-mail: xyzou@nju.edu.cn [Key Laboratory of Modern Acoustics, MOE, Department of Physics, Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093 (China); Liang, Bin; Cheng, Jian-Chun [Key Laboratory of Modern Acoustics, MOE, Department of Physics, Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093 (China)

    2015-07-15

    In this review, a brief introduction is given to the development of acoustic superlens cloaks that allow the cloaked object to receive signals while its presence is not sensed by the surrounding, which can be regarded as “cloaking an acoustic sensor”. Remarkably, the designed cloak consists of single-negative materials with parameters independent of the background medium or the sensor system, which is proven to be a magnifying superlens. This has facilitated significantly the design and fabrication of acoustic cloaks that generally require double-negative materials with customized parameters. Such innovative design has then been simplified further as a multi-layered structure comprising of two alternately arranged complementary media with homogeneous isotropic single-negative materials. Based on this, a scattering analyses method is developed for the numerical simulation of such multi-layered cloak structures, which may serve as an efficient approach for the investigation on such devices.

  9. Cloaking through cancellation of diffusive wave scattering

    KAUST Repository

    Farhat, Mohamed

    2016-08-10

    A new cloaking mechanism, which makes enclosed objects invisible to diffusive photon density waves, is proposed. First, diffusive scattering from a basic core-shell geometry, which represents the cloaked structure, is studied. The conditions of scattering cancellation in a quasi-static scattering regime are derived. These allow for tailoring the diffusivity constant of the shell enclosing the object so that the fields scattered from the shell and the object cancel each other. This means that the photon flow outside the cloak behaves as if the cloaked object were not present. Diffusive light invisibility may have potential applications in hiding hot spots in infrared thermography or tissue imaging. © 2016 The Author(s) Published by the Royal Society. All rights reserved.

  10. Electret electrostatic cloak

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Lunwu; Zhao, Yanyan; Zhao, Zhigang; Li, Hua, E-mail: 12.66@163.com

    2015-04-01

    We report that a bi-layer electret cylinder can cloak electrostatic field. We fabricated two hollow electret cylinders, the two hollow electret cylinders nested a bi-layer hollow electret cylinder. The direction of the polarization intensity is parallel to one of the diameters. Experimental results show that the bi-layer hollow electret cylinder can cloak electrostatic field.

  11. Molding acoustic, electromagnetic and water waves with a single cloak.

    Science.gov (United States)

    Xu, Jun; Jiang, Xu; Fang, Nicholas; Georget, Elodie; Abdeddaim, Redha; Geffrin, Jean-Michel; Farhat, Mohamed; Sabouroux, Pierre; Enoch, Stefan; Guenneau, Sébastien

    2015-06-09

    We describe two experiments demonstrating that a cylindrical cloak formerly introduced for linear surface liquid waves works equally well for sound and electromagnetic waves. This structured cloak behaves like an acoustic cloak with an effective anisotropic density and an electromagnetic cloak with an effective anisotropic permittivity, respectively. Measured forward scattering for pressure and magnetic fields are in good agreement and provide first evidence of broadband cloaking. Microwave experiments and 3D electromagnetic wave simulations further confirm reduced forward and backscattering when a rectangular metallic obstacle is surrounded by the structured cloak for cloaking frequencies between 2.6 and 7.0 GHz. This suggests, as supported by 2D finite element simulations, sound waves are cloaked between 3 and 8 KHz and linear surface liquid waves between 5 and 16 Hz. Moreover, microwave experiments show the field is reduced by 10 to 30 dB inside the invisibility region, which suggests the multi-wave cloak could be used as a protection against water, sonic or microwaves.

  12. Molding acoustic, electromagnetic and water waves with a single cloak

    KAUST Repository

    Xu, Jun

    2015-06-09

    We describe two experiments demonstrating that a cylindrical cloak formerly introduced for linear surface liquid waves works equally well for sound and electromagnetic waves. This structured cloak behaves like an acoustic cloak with an effective anisotropic density and an electromagnetic cloak with an effective anisotropic permittivity, respectively. Measured forward scattering for pressure and magnetic fields are in good agreement and provide first evidence of broadband cloaking. Microwave experiments and 3D electromagnetic wave simulations further confirm reduced forward and backscattering when a rectangular metallic obstacle is surrounded by the structured cloak for cloaking frequencies between 2.6 and 7.0 GHz. This suggests, as supported by 2D finite element simulations, sound waves are cloaked between 3 and 8 KHz and linear surface liquid waves between 5 and 16 Hz. Moreover, microwave experiments show the field is reduced by 10 to 30 dB inside the invisibility region, which suggests the multi-wave cloak could be used as a protection against water, sonic or microwaves. © 2015, Nature Publishing Group. All rights reserved.

  13. Three-dimensional invisibility cloaks functioning at terahertz frequencies

    Science.gov (United States)

    Cao, Wei; Zhou, Fan; Liang, Dachuan; Gu, Jianqiang; Han, Jiaguang; Sun, Cheng; Zhang, Weili

    2014-05-01

    Quasi-three-dimensional invisibility cloaks, comprised of either homogeneous or inhomogeneous media, are experimentally demonstrated in the terahertz regime. The inhomogeneous cloak was lithographically fabricated using a scalable Projection Microstereolithography process. The triangular cloaking structure has a total thickness of 4.4 mm, comprised of 220 layers of 20 μm thickness. The cloak operates at a broad frequency range between 0.3 and 0.6 THz, and is placed over an α-lactose monohydrate absorber with rectangular shape. Characterized using angular-resolved reflection terahertz time-domain spectroscopy, the results indicate that the terahertz invisibility cloak has successfully concealed both the geometrical and spectroscopic signatures of the absorber, making it undetectable to the observer. The homogeneous cloaking device made from birefringent crystalline sapphire features a large concealed volume, low loss, and broad bandwidth. It is capable of hiding objects with a dimension nearly an order of magnitude larger than that of its lithographic counterpart, but without involving complex and time-consuming cleanroom processing. The cloak device was made from two 20-mm-thick high-purity sapphire prisms. The cloaking region has a maximum height 1.75 mm with a volume of approximately 5% of the whole sample. The reflected TM beam from the cloak shows nearly the same profile as that reflected by a flat mirror.

  14. Broadband Acoustic Cloak for Ultrasound Waves

    CERN Document Server

    Zhang, Shu; Fang, Nicholas

    2010-01-01

    Invisibility devices based on coordinate transformation have opened up a new field of considerable interest. Such a device is proposed to render the hidden object undetectable under the flow of light or sound, by guiding and controlling the wave path through an engineered space surrounding the object. We present here the first practical realization of a low-loss and broadband acoustic cloak for underwater ultrasound. This metamaterial cloak is constructed with a network of acoustic circuit elements, namely serial inductors and shunt capacitors. Our experiment clearly shows that the acoustic cloak can effectively bend the ultrasound waves around the hidden object, with reduced scattering and shadow. Due to the non-resonant nature of the building elements, this low loss (~6dB/m) cylindrical cloak exhibits excellent invisibility over a broad frequency range from 52 to 64 kHz in the measurements. The low visibility of the cloaked object for underwater ultrasound shed a light on the fundamental understanding of ma...

  15. Ray-optics cloaking devices for large objects in incoherent natural light

    Science.gov (United States)

    Chen, Hongsheng; Zheng, Bin; Shen, Lian; Wang, Huaping; Zhang, Xianmin; Zheludev, Nikolay I.; Zhang, Baile

    2013-01-01

    A cloak that can hide living creatures from sight is a common feature of mythology but still remains unrealized as a practical device. To preserve the wave phase, the previous cloaking solution proposed by Pendry and colleagues required transformation of the electromagnetic space around the hidden object in such a way that the rays bending around the object inside the cloak region have to travel faster than those passing it by. This difficult phase preservation requirement is the main obstacle for building a broadband polarization-insensitive cloak for large objects. Here we propose a simplified version of Pendry’s cloak by abolishing the requirement for phase preservation, as it is irrelevant for observation using incoherent natural light with human eyes, which are phase and polarization insensitive. This allows for a cloak design on large scales using commonly available materials. We successfully demonstrate the cloaking of living creatures, a cat and a fish, from the eye. PMID:24153410

  16. Experiments on elastic cloaking in thin plates.

    Science.gov (United States)

    Stenger, Nicolas; Wilhelm, Manfred; Wegener, Martin

    2012-01-06

    Following a theoretical proposal [M. Farhat et al., Phys. Rev. Lett. 103, 024301 (2009)], we design, fabricate, and characterize a cloaking structure for elastic waves in 1 mm thin structured polymer plates. The cloak consists of 20 concentric rings of 16 different metamaterials, each being a tailored composite of polyvinyl chloride and polydimethylsiloxane. By using stroboscopic imaging with a camera from the direction normal to the plate, we record movies of the elastic waves for monochromatic plane-wave excitation. We observe good cloaking behavior for carrier frequencies in the range from 200 to 400 Hz (one octave), in good agreement with a complete continuum-mechanics numerical treatment. This system is thus ideally suited for demonstration experiments conveying the ideas of transformation optics.

  17. Mechanical cloak design by direct lattice transformation.

    Science.gov (United States)

    Bückmann, Tiemo; Kadic, Muamer; Schittny, Robert; Wegener, Martin

    2015-04-21

    Spatial coordinate transformations have helped simplifying mathematical issues and solving complex boundary-value problems in physics for decades already. More recently, material-parameter transformations have also become an intuitive and powerful engineering tool for designing inhomogeneous and anisotropic material distributions that perform wanted functions, e.g., invisibility cloaking. A necessary mathematical prerequisite for this approach to work is that the underlying equations are form invariant with respect to general coordinate transformations. Unfortunately, this condition is not fulfilled in elastic-solid mechanics for materials that can be described by ordinary elasticity tensors. Here, we introduce a different and simpler approach. We directly transform the lattice points of a 2D discrete lattice composed of a single constituent material, while keeping the properties of the elements connecting the lattice points the same. After showing that the approach works in various areas, we focus on elastic-solid mechanics. As a demanding example, we cloak a void in an effective elastic material with respect to static uniaxial compression. Corresponding numerical calculations and experiments on polymer structures made by 3D printing are presented. The cloaking quality is quantified by comparing the average relative SD of the strain vectors outside of the cloaked void with respect to the homogeneous reference lattice. Theory and experiment agree and exhibit very good cloaking performance.

  18. Invisibility cloaking in weak scattering

    NARCIS (Netherlands)

    Setälä, Tero; Hakkarainen, Timo; Friberg, Ari T.; Hoenders, Bernhard J.

    2010-01-01

    We consider invisibility cloaking of a slab object in scalar wave theory within the first-order Born approximation. We show that in the forward direction cloaking is achieved for any object slab and incident field, whereas in the backward direction cloaking is possible at least for self-imaging fiel

  19. Cloaking and Magnifying Using Radial Anisotropy

    CERN Document Server

    Kettunen, Henrik; Sihvola, Ari

    2013-01-01

    This paper studies the electrostatic responses of a polarly radially anisotropic cylinder and a spherically radially anisotropic sphere. For both geometries, the permittivity components differ from each other in the radial and tangential directions. We show that choosing the ratio between these components in a certain way, these rather simple structures can be used in cloaking dielectric inclusions with arbitrary permittivity and shape in the quasi-static limit. For an ideal cloak, the contrast between the permittivity components has to tend to infinity. However, only positive permittivity values are required and a notable cloaking effect can already be observed with relatively moderate permittivity contrasts. Furthermore, we show that the polarly anisotropic cylindrical shell has a complementary capability of magnifying the response of an inner cylinder.

  20. Coordinate transformations and matter waves cloaking

    Science.gov (United States)

    Mohammadi, G. R.; Moghaddam, A. G.; Mohammadkhani, R.

    2016-03-01

    Transformation method provides an efficient tool to control wave propagation inside the materials. Using the coordinate transformation approach, we study invisibility cloaks with sphere, cylinder and ellipsoid structures for electronic waves propagation. The underlying physics behind this investigation is the fact that Schrödinger equation with position dependent mass tensor and potentials has a covariant form which follows the coordinate transformation. Using this technique we obtain the exact spatial form of the mass tensor and potentials for a variety of cloaks with different shapes.

  1. Thermal cloak-concentrator

    Science.gov (United States)

    Shen, Xiangying; Li, Ying; Jiang, Chaoran; Ni, Yushan; Huang, Jiping

    2016-07-01

    For macroscopically manipulating heat flow at will, thermal metamaterials have opened a practical way, which possesses a single function, such as either cloaking or concentrating the flow of heat even though environmental temperature varies. By developing a theory of transformation heat transfer for multiple functions, here we introduce the concept of intelligent thermal metamaterials with a dual function, which is in contrast to the existing thermal metamaterials with single functions. By assembling homogeneous isotropic materials and shape-memory alloys, we experimentally fabricate a kind of intelligent thermal metamaterials, which can automatically change from a cloak (or concentrator) to a concentrator (or cloak) when the environmental temperature changes. This work paves an efficient way for a controllable gradient of heat, and also provides guidance both for arbitrarily manipulating the flow of heat and for efficiently designing similar intelligent metamaterials in other fields.

  2. Broadband cloaking for flexural waves

    CERN Document Server

    Zareei, Ahmad

    2016-01-01

    The governing equation for elastic waves in flexural plates is not form invariant, and hence designing a cloak for such waves faces a major challenge. Here, we present the design of a perfect broadband cloak for flexural waves through the use of a nonlinear transformation, and by matching term-by-term the original and transformed equations. For a readily achievable flexural cloak in a physical setting, we further present an approximate adoption of our perfect cloak under more restrictive physical constraints. Through direct simulation of the governing equations, we show that this cloak, as well, maintains a consistently high cloaking efficiency over a broad range of frequencies. The methodology developed here may be used for steering waves and designing cloaks in other physical systems with non form-invariant governing equations.

  3. Acoustic carpet invisibility cloak with two open windows using multilayered homogeneous isotropic material

    Institute of Scientific and Technical Information of China (English)

    Ren Chun-Yu; Xiang Zhi-Hai; Cen Zhang-Zhi

    2011-01-01

    We present a method for designing an open acoustic cloak that can conceal a perturbation on flat ground and simultaneously meet the requirement of communication and matter interchange between the inside and the outside of the cloak.This cloak can be constructed with a multilayered structure and each layer is an isotropic and homogeneous medium.The design scheme consists of two steps:firstly,we apply a conformal coordinate transformation to obtain a quasi-perfect cloak with heterogeneous isotropic material; then,according to the profile of the material distribution,we degenerate this cloak into a multilayered-homogeneous isotropic cloak,which has two open windows with negligible disturbance on its invisibility performance.This may greatly facilitate the fabrication and enhance the applicability of such a carpet-type cloak.

  4. Add-on unidirectional elastic metamaterial plate cloak.

    Science.gov (United States)

    Lee, Min Kyung; Kim, Yoon Young

    2016-02-10

    Metamaterial cloaks control the propagation of waves to make an object invisible or insensible. To manipulate elastic waves in space, a metamaterial cloak is typically embedded in a base system that includes or surrounds a target object. The embedding is undesirable because it structurally weakens or permanently alters the base system. In this study, we propose a new add-on metamaterial elastic cloak that can be placed over and mechanically coupled with a base structure without embedding. We designed an add-on type annular metamaterial plate cloak through conformal mapping, fabricated it and performed cloaking experiments in a thin-plate with a hole. Experiments were performed in a thin plate by using the lowest symmetric Lamb wave centered at 100 kHz. As a means to check the cloaking performance of the add-on elastic plate cloak, possibly as a temporary stress reliever or a so-called "stress bandage", the degree of stress concentration mitigation and the recovery from the perturbed wave field due to a hole were investigated.

  5. A hybrid Scatter/Transform cloaking model

    Directory of Open Access Journals (Sweden)

    Gad Licht

    2015-01-01

    Full Text Available A new Scatter/Transform cloak is developed that combines the light bending of refraction characteristic of a Transform cloak with the scatter cancellation characteristic of a Scatter cloak. The hybrid cloak incorporates both Transform’s variable index of refraction with modified linear intrusions to maximize the Scatter cloak effect. Scatter/Transform improved the scattering cross-section of cloaking in a 2-dimensional space to 51.7% compared to only 39.6% or 45.1% respectively with either Scatter or Transform alone. Metamaterials developed with characteristics based on the new ST hybrid cloak will exhibit superior cloaking capabilities.

  6. Grating-Coupled Waveguide Cloaking

    Institute of Scientific and Technical Information of China (English)

    WANG Jia-Fu; QU Shao-Bo; XU Zhuo; MA Hua; WANG Cong-Min; XIA Song; WANG Xin-Hua; ZHOU Hang

    2012-01-01

    Based on the concept of a grating-coupled waveguide (GCW),a new strategy for realizing EM cloaking is presented.Using metallic grating,incident waves are firstly coupled into the effective waveguide and then decoupled into free space behind,enabling EM waves to pass around the obstacle.Phase compensation in the waveguide keeps the wave-front shape behind the obstacle unchanged.Circular,rectangular and triangular cloaks are presented to verify the robustness of the GCW cloaking.Electric field animations and radar cross section (RCS)comparisons convincingly demonstrate the cloaking effect.

  7. Two-dimensional cylindrical thermal cloak designed by implicit transformation method

    Science.gov (United States)

    Yuan, Xuebo; Lin, Guochang; Wang, Youshan

    2016-07-01

    As a new-type technology of heat management, thermal metamaterials have attracted more and more attentions recently and thermal cloak is a typical case. Thermal conductivity of thermal cloak designed by coordinate transformation method is usually featured by inhomogeneity, anisotropy and local singularity. Explicit transformation method, which is commonly used to design thermal cloak with the coordinate transformation known in advance, has insufficient flexibility, making it hard to proactively reduce the difficulty of device fabrication. In this work, we designed the thermal conductivity of two-dimensional (2D) cylindrical thermal cloak using the implicit transformation method without knowledge of the coordinate transformation in advance. With two classes of generation functions taken into consideration, this study adopted full-wave simulations to analyze the thermal cloaking performances of designed thermal cloaks. Material distributions and simulation results showed that the implicit transformation method has high flexibility. The form of coordinate transformation not only influences the homogeneity and anisotropy but also directly influences the thermal cloaking performance. An improved layered structure for 2D cylindrical thermal cloak was put forward based on the generation function g(r) = r15, which reduces the number of the kinds of constituent materials while guaranteeing good thermal cloaking performance. This work provides a beneficial guidance for reducing the fabrication difficulty of thermal cloak.

  8. Broad band invisibility cloak made of normal dielectric multilayer

    CERN Document Server

    Xu, Xiaofei; Xiong, Shuai; Fan, Jinlong; Zhao, Jun-Ming; Jiang, Tian

    2011-01-01

    We present the design, fabrication and performance test of a quasi three-dimensional carpet cloak made of normal dielectric in the microwave regime. Taking advantage of a simple linear coordinate transformation we design a carpet cloak with homogeneous anisotropic medium and then practically realize the device with multilayer of alternating normal dielectric slabs based on the effective medium theory. As a proof-of-concept example, we fabricate the carpet cloak with multilayer of FR4 dielectric slabs with air spacing. The performance of the fabricated design is verified through full-wave numerical simulation and measurement of the far-field scattering electromagnetic waves in a microwave anechoic chamber. Experimental results have demonstrated pronounced cloaking effect in a very broad band from 8 GHz to 18 GHz (whole X and Ku band) due to the low loss, non-dispersive feature of the multilayer dielectric structure.

  9. Non-magnetic simplified cylindrical cloak with suppressed zero-th order scattering

    CERN Document Server

    Yan, Wei; Qiu, Min

    2008-01-01

    A new type of simplified cloaks with matched exterior boundaries is proposed. The cloak uses non-magnetic material for the TM polarization and can function with a relatively thin thickness. It is shown that the $zero^{th}$ order scattering of such cloak is dominant among all cylindrical scattering terms. A gap is added at the cloak's inner surface to eliminate the zero-th order scattering, through the mechanism of scattering resonance. The reduction in scattering is relatively smooth, indicating that the proposed scattering reduction method has good tolerance to perturbations. Numerical simulations also confirm that the proposed structure has very low scattering.

  10. Regularized Transformation-Optics Cloaking for the Helmholtz Equation: From Partial Cloak to Full Cloak

    Science.gov (United States)

    Li, Jingzhi; Liu, Hongyu; Rondi, Luca; Uhlmann, Gunther

    2015-04-01

    We develop a very general theory on the regularized approximate invisibility cloaking for the wave scattering governed by the Helmholtz equation in any space dimensions via the approach of transformation optics. There are four major ingredients in our proposed theory: (1) The non-singular cloaking medium is obtained by the push-forwarding construction through a transformation that blows up a subset in the virtual space, where is an asymptotic regularization parameter. will degenerate to K 0 as , and in our theory K 0 could be any convex compact set in , or any set whose boundary consists of Lipschitz hypersurfaces, or a finite combination of those sets. (2) A general lossy layer with the material parameters satisfying certain compatibility integral conditions is employed right between the cloaked and cloaking regions. (3) The contents being cloaked could also be extremely general, possibly including, at the same time, generic mediums and, sound-soft, sound-hard and impedance-type obstacles, as well as some sources or sinks. (4) In order to achieve a cloaking device of compact size, particularly for the case when is not "uniformly small", an assembly-by-components, the (ABC) geometry is developed for both the virtual and physical spaces and the blow-up construction is based on concatenating different components. Within the proposed framework, we show that the scattered wave field corresponding to a cloaking problem will converge to u 0 as , with u 0 being the scattered wave field corresponding to a sound-hard K 0. The convergence result is used to theoretically justify the approximate full and partial invisibility cloaks, depending on the geometry of K 0. On the other hand, the convergence results are conducted in a much more general setting than what is needed for the invisibility cloaking, so they are of significant mathematical interest for their own sake. As for applications, we construct three types of full and partial cloaks. Some numerical experiments are

  11. Analysis of flexural wave cloaks

    Directory of Open Access Journals (Sweden)

    Alfonso Climente

    2016-12-01

    Full Text Available This work presents a comprehensive study of the cloak for bending waves theoretically proposed by Farhat et al. [see Phys. Rev. Lett. 103, 024301 (2009] and later on experimentally realized by Stenger et al. [see Phys. Rev. Lett. 108, 014301 (2012]. This study uses a semi-analytical approach, the multilayer scattering method, which is based in the Kirchoff-Love wave equation for flexural waves in thin plates. Our approach was unable to reproduce the predicted behavior of the theoretically proposed cloak. This disagreement is here explained in terms of the simplified wave equation employed in the cloak design, which employed unusual boundary conditions for the cloaking shell. However, our approach reproduces fairly well the measured displacement maps for the fabricated cloak, indicating the validity of our approach. Also, the cloak quality has been here analyzed using the so called averaged visibility and the scattering cross section. The results obtained from both analysis let us to conclude that there is room for further improvements of this type of flexural wave cloak by using better design procedures.

  12. Analysis of flexural wave cloaks

    Science.gov (United States)

    Climente, Alfonso; Torrent, Daniel; Sánchez-Dehesa, José

    2016-12-01

    This work presents a comprehensive study of the cloak for bending waves theoretically proposed by Farhat et al. [see Phys. Rev. Lett. 103, 024301 (2009)] and later on experimentally realized by Stenger et al. [see Phys. Rev. Lett. 108, 014301 (2012)]. This study uses a semi-analytical approach, the multilayer scattering method, which is based in the Kirchoff-Love wave equation for flexural waves in thin plates. Our approach was unable to reproduce the predicted behavior of the theoretically proposed cloak. This disagreement is here explained in terms of the simplified wave equation employed in the cloak design, which employed unusual boundary conditions for the cloaking shell. However, our approach reproduces fairly well the measured displacement maps for the fabricated cloak, indicating the validity of our approach. Also, the cloak quality has been here analyzed using the so called averaged visibility and the scattering cross section. The results obtained from both analysis let us to conclude that there is room for further improvements of this type of flexural wave cloak by using better design procedures.

  13. Temperature controlled infrared broadband cloaking with the bilayer coatings of semiconductor and superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaohua [College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); College of Physics and Electronics, Yancheng Teachers University, Yancheng 224051 (China); Liu, Youwen, E-mail: ywliu@nuaa.edu.cn [College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Feng, Yuncai [College of Science, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)

    2015-06-15

    Highlights: • We first propose that the cloak is composed of the bilayer of semiconductor and superconductor. • We realize the infrared broadband cloaking based on the scattering cancellation method. • The cloaking frequency can be tuned by external temperature. - Abstract: The infrared broadband tunable cloaking have been proposed and investigated with the bilayer coating materials of semiconductor (n-Ge) and high-temperature superconductor (YBa{sub 2}Cu{sub 3}O{sub 7}), whose cloaking frequency can be controlled by external temperature. The analytical solution is derived based on the scattering cancellation cloaking technique from the Mie scattering theory, and the full-wave numerical simulation is performed by the finite element method. The calculated and simulated results have demonstrated that this invisibility cloak may reduce the total scattering cross section of the composite structure of 90% over a broad frequency band of nearly 20 THz, and the infrared cloaking frequency can be tuned by the external temperature. It can provide a feasible way to design a broadband tunable cloak.

  14. Three-dimensional broadband acoustic illusion cloak for sound-hard boundaries of curved geometry

    Science.gov (United States)

    Kan, Weiwei; Liang, Bin; Li, Ruiqi; Jiang, Xue; Zou, Xin-Ye; Yin, Lei-Lei; Cheng, Jianchun

    2016-11-01

    Acoustic illusion cloaks that create illusion effects by changing the scattered wave have many potential applications in a variety of scenarios. However, the experimental realization of generating three-dimensional (3D) acoustic illusions under detection of broadband signals still remains challenging despite the paramount importance for practical applications. Here we report the design and experimental demonstration of a 3D broadband cloak that can effectively manipulate the scattered field to generate the desired illusion effect near curved boundaries. The designed cloak simply comprises positive-index anisotropic materials, with parameters completely independent of either the cloaked object or the boundary. With the ability of manipulating the scattered field in 3D space and flexibility of applying to arbitrary geometries, our method may take a major step toward the real world application of acoustic cloaks and offer the possibilities of building advanced acoustic devices with versatile functionalities.

  15. Robust large dimension terahertz cloaking

    CERN Document Server

    Liang, Dachuan; Han, Jiaguang; Yang, Yuanmu; Zhang, Shuang; Zhang, Weili

    2011-01-01

    Invisibility cloaking not only catches the human imagination, but also promises fascinating applications in optics and photonics. By manipulating electromagnetic waves with metamaterials, researchers have been able to realize electromagnetic cloaking in the microwave, terahertz and optical regimes. Nevertheless, the complex design and fabrication process, narrow bandwidth, and high intrinsic losses in the metamaterial-based cloaks have imposed intractable limitations on their realistic applications. Seeking new approaches to overcome these perceived disadvantages is in progress. Here by using uniform sapphire crystal, we demonstrate the first homogenous invisibility cloak functioning at terahertz frequencies. The terahertz invisibility device features a large concealed volume, low loss, and broad bandwidth. In particular, it is capable of hiding objects with a dimension nearly an order of magnitude larger than that of its lithographic counterpart, but without involving complex and time-consuming cleanroom pro...

  16. Extremely Thin Dielectric Metasurface for Carpet Cloaking

    CERN Document Server

    Hsu, LiYi; Kanté, Boubacar

    2015-01-01

    We demonstrate a novel and simple approach to cloaking a scatterer on a ground plane. We use an extremely thin dielectric metasurface ({\\lambda}/12) to reshape the wavefronts distorted by a scatterer in order to mimic the reflection pattern of a flat ground plane. To achieve such carpet cloaking, the reflection angle has to be equal to the incident angle everywhere on the scatterer. We use a graded metasurface and calculate the required phase gradient to achieve cloaking. Our metasurface locally provides additional phase to the wavefronts to compensate for the phase difference amongst light paths induced by the geometrical distortion. We design our metasurface in the microwave range using highly sub-wavelength dielectric resonators. We verify our design by full-wave time-domain simulations using micro-structured resonators and show that results match theory very well. This approach can be applied to hide any scatterer on a ground plane not only at microwave frequencies, but also at higher frequencies up to th...

  17. Scattering cross-section of a transformation optics-based metamaterial cloak

    Energy Technology Data Exchange (ETDEWEB)

    Kundtz, Nathan; Gaultney, Daniel; Smith, David R, E-mail: nbk@duke.ed [Center for Metamaterials and Integrated Plasmonics, Electrical and Computer Engineering, Duke University, Durham, NC (United States)

    2010-04-15

    We present experimental quantitative scattering cross-section (SCS) measurements for a metamaterial cloak. The cloak is nearly identical to that reported in 2006; however, quantitative experimental measurements have not yet been reported for such a structure. This cylindrically symmetric cloak is designed to operate at a frequency of 10 GHz and to reduce the SCS of a cylinder 50 mm in diameter. Despite being only a crude approximation of the ideal transformation optical design, the fabricated metamaterial cloak is shown to reduce the SCS of the cylinder over the frequency range from 9.91 to 10.14 GHz, a span of 230 MHz or a 2.3% bandwidth. The maximum reduction in the SCS is 24%. This result provides a useful experimental, quantitative benchmark that can form the basis for comparison of the performances of future improved cloaking structures.

  18. Structural rehabilitation of old buildings

    CERN Document Server

    Guedes, João; Varum, Humberto

    2014-01-01

    The present book describes the different construction systems and structural materials and solutions within the main old buildings typologies, and it analyses the particularities of each of them, including mechanical properties, structural behaviour, typical damage patterns and collapse mechanisms. Common or pioneering intervention measures to repair and/or strengthen some of these structural elements are also reviewed.

  19. Broadband unidirectional cloak designed by eikonal theory.

    Science.gov (United States)

    Liu, Xuan; Wu, Xiaojia; Zhang, Luoning; Zhou, Jing

    2015-11-02

    A method for designing optical device is derived based on the eikonal theory, which could obtain the eikonal distribution on a curved surface according to the propagation characteristics of the subsequent light wave. Then combining with the phase matching condition, we designed a broadband unidirectional cloak. Different from the reported unidirectional cloaks, the proposed one could be used for coherent wave and has continuous broadband performance. Moreover, it has three cloaked regions. Full-wave simulation results verify the properties of the cloak.

  20. Metasurface Cloaks for Large Cylindrical Cluster Configurations

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Yakovlev, A.B.

    2014-01-01

    small cylinders, we demonstrate that even electrically large clusters of such particles can be cloaked by covering its constituent cylinders with the metasurface cloaks. This holds for densely packed cylinders due to significantly reduced coupling by the presence of the cloaks. The results may...

  1. Rigorous analysis of non-magnetic cloaks

    DEFF Research Database (Denmark)

    Zhang, Jingjing; Luo, Yu; Mortensen, Asger

    2010-01-01

    theory. It is demonstrated that the forward scattering of the impedance matched cloak increases dramatically as the thickness of the cloak decreases. Nevertheless, it is still possible to effectively reduce the total scattering cross section with a very thin cloak whose impedance is not matched...

  2. Minimizing the scattering of a nonmagnetic cloak

    DEFF Research Database (Denmark)

    Zhang, Jingjing; Luo, Yu; Mortensen, Asger

    2010-01-01

    theory. It is demonstrated that the forward scattering of the impedance matched cloak increases dramatically as the thickness of the cloak decreases. Nevertheless, it is still possible to effectively reduce the total scattering cross section with a very thin cloak whose impedance is not matched...

  3. An Electromagnetic GL Double Layered Cloak

    CERN Document Server

    Xie, Ganquan; Xie, Feng; Xie, Lee

    2009-01-01

    In this paper, we propose a new electromagnetic (EM) GL double layered cloak. The GL double layered cloak is consist of two sphere annular layers, $R_1 \\le r \\le R_2$ and $R_2 \\le r \\le R_3$. Two type cloak materials are proposed and installed in the each layer, respectively. The outer layer cloak of the GL double layered cloak has the invisible function, the inner layer cloak has fully absorption function. The GL double layered metamaterials are weak degenerative and weak dispersive. When the source is located outside of the GL double layered cloak, the excited EM wave field propagation outside of the double layered cloak is as same as in free space and never be disturbed by the cloak; also, the exterior EM wave can not penetrate into the inner layer and concealment. When local sources are located inside of the GL double cloaked concealment with the normal EM materials, the excited EM wave is propagating under Maxwell equation governing, it is complete absorbed by the inner layer cloak of GL double cloak and...

  4. EDITORIAL: Focus on Cloaking and Transformation Optics

    Science.gov (United States)

    Leonhardt, Ulf; Smith, David R.

    2008-11-01

    'Any sufficiently advanced technology is indistinguishable from magic', as the late Arthur C Clarke wrote. So what does it take to do magic by technology? Transformation optics has developed some tantalizing ideas and the first practical demonstrations of 'pure and applied magic'. Transformation optics gathers an unusual mix of scientists, ranging from practically-minded engineers to imaginative theoretical physicists and mathematicians or hybrids of all three. The engineers have been developing new materials with extraordinary electromagnetic properties, from materials for microwaves, to be used in radar or wireless technology, to materials for terahertz radiation and visible light. These materials typically are composites—they consist of artificial structures much smaller than the wavelength that act like man-made atoms, apart being much larger in size. The properties of these artificial atoms depend on their shapes and sizes and so they are tunable, in contrast to most real atoms or molecules. This degree of control is what makes these materials—called metamaterials—so interesting. Such new-won freedom invites the other side of the spectrum of scientists, the theorists, to dream. Just imagine there are no practical limits on electromagnetic materials—what could we do with them? One exciting application of metamaterials has been Veselago's idea of negative refraction, dating back to the 1960s. Metamaterials have breathed life into Veselago's idea, culminating in recent optical demonstrations (see for example [1,2]). Another application is cloaking, developing ideas and first experimental demonstrations for invisibility devices [3]. It turns out that both negative refraction and cloaking are examples where materials seem to transform the geometry of space. Any optical material appears to change light's perception of space, as countless optical illusions prove, but the materials of transformation optics act in more specific ways: they appear to perform

  5. Decoupling antennas in printed technology using elliptical metasurface cloaks

    Energy Technology Data Exchange (ETDEWEB)

    Bernety, Hossein M., E-mail: hmehrpou@go.olemiss.edu, E-mail: yakovlev@olemiss.edu; Yakovlev, Alexander B., E-mail: hmehrpou@go.olemiss.edu, E-mail: yakovlev@olemiss.edu [Center for Applied Electromagnetic Systems Research (CAESR), Department of Electrical Engineering, University of Mississippi, University, Mississippi 38677-1848 (United States)

    2016-01-07

    In this paper, we extend the idea of reducing the electromagnetic interactions between transmitting radiators to the case of widely used planar antennas in printed technology based on the concept of mantle cloaking. Here, we show that how lightweight elliptical metasurface cloaks can be engineered to restore the intrinsic properties of printed antennas with strip inclusions. In order to present the novel approach, we consider two microstrip-fed monopole antennas resonating at slightly different frequencies cloaked by confocal elliptical metasurfaces formed by arrays of sub-wavelength periodic elements, partially embedded in the substrate. The presence of the metasurfaces leads to the drastic suppression of mutual near-field and far-field couplings between the antennas, and thus, their radiation patterns are restored as if they were isolated. Moreover, it is worth noting that this approach is not limited to printed radiators and can be applied to other planar structures as well.

  6. Optical Neutrality: Invisibility without Cloaking

    CERN Document Server

    Hodges, Reed; Durach, Maxim

    2016-01-01

    We show that it is possible to design an invisible wavelength-sized metal-dielectric metamaterial object without evoking cloaking. Our approach is an extension of the neutral inclusion concept by Zhou and Hu [Phys.Rev.E 74, 026607 (2006)] to Mie scatterers. We demonstrate that an increase of metal fraction in the metamaterial leads to a transition from dielectric-like to metal-like scattering, which proceeds through invisibility or optical neutrality of the scatterer. Formally this is due to cancellation of multiple scattering orders, similarly to plasmonic cloaking introduced by Alu and Engheta [Phys.Rev.E 72, 016623 (2005)], but without introduction of the separation of the scatterer into cloak and hidden regions.

  7. Cloaking a metal object from an electromagnetic pulse: A comparison between various cloaking techniques

    CERN Document Server

    Alitalo, Pekka; Tretyakov, Sergei

    2009-01-01

    Electromagnetic cloaks are devices that can be used to reduce the total scattering cross section of various objects. An ideal cloak removes all scattering from an object and thus makes this object "invisible" to the electromagnetic fields that impinge on the object. However, ideal cloaking appears to be possible only at a single frequency. To study cloaking from an electromagnetic pulse we consider propagation of a pulse inside a waveguide with a cloaked metal object inside. There are several ways to achieve cloaking and in this paper we study three such methods, namely, the coordinate-transformation cloak, the transmission-line cloak, and the metal-plate cloak. In the case of the two last cloaks, pulse propagation is studied using experimental data whereas the coordinate-transformation cloak is studied with numerical simulations. The results show that, at least in the studied cases where the cloaked object's diameter is smaller than the wavelength, the cloaks based on transmission-line meshes and metal plate...

  8. Detecting Thermal Cloaks via Transient Effects

    Science.gov (United States)

    Sklan, Sophia R.; Bai, Xue; Li, Baowen; Zhang, Xiang

    2016-09-01

    Recent research on the development of a thermal cloak has concentrated on engineering an inhomogeneous thermal conductivity and an approximate, homogeneous volumetric heat capacity. While the perfect cloak of inhomogeneous κ and inhomogeneous ρcp is known to be exact (no signals scattering and only mean values penetrating to the cloak’s interior), the sensitivity of diffusive cloaks to defects and approximations has not been analyzed. We analytically demonstrate that these approximate cloaks are detectable. Although they work as perfect cloaks in the steady-state, their transient (time-dependent) response is imperfect and a small amount of heat is scattered. This is sufficient to determine the presence of a cloak and any heat source it contains, but the material composition hidden within the cloak is not detectable in practice. To demonstrate the feasibility of this technique, we constructed a cloak with similar approximation and directly detected its presence using these transient temperature deviations outside the cloak. Due to limitations in the range of experimentally accessible volumetric specific heats, our detection scheme should allow us to find any realizable cloak, assuming a sufficiently large temperature difference.

  9. Detecting Thermal Cloaks via Transient Effects

    Science.gov (United States)

    Sklan, Sophia R.; Bai, Xue; Li, Baowen; Zhang, Xiang

    2016-01-01

    Recent research on the development of a thermal cloak has concentrated on engineering an inhomogeneous thermal conductivity and an approximate, homogeneous volumetric heat capacity. While the perfect cloak of inhomogeneous κ and inhomogeneous ρcp is known to be exact (no signals scattering and only mean values penetrating to the cloak’s interior), the sensitivity of diffusive cloaks to defects and approximations has not been analyzed. We analytically demonstrate that these approximate cloaks are detectable. Although they work as perfect cloaks in the steady-state, their transient (time-dependent) response is imperfect and a small amount of heat is scattered. This is sufficient to determine the presence of a cloak and any heat source it contains, but the material composition hidden within the cloak is not detectable in practice. To demonstrate the feasibility of this technique, we constructed a cloak with similar approximation and directly detected its presence using these transient temperature deviations outside the cloak. Due to limitations in the range of experimentally accessible volumetric specific heats, our detection scheme should allow us to find any realizable cloak, assuming a sufficiently large temperature difference. PMID:27605153

  10. Full and Partial Cloaking in Electromagnetic Scattering

    Science.gov (United States)

    Deng, Youjun; Liu, Hongyu; Uhlmann, Gunther

    2017-01-01

    In this paper, we consider two regularized transformation-optics cloaking schemes for electromagnetic (EM) waves. Both schemes are based on the blowup construction with the generating sets being, respectively, a generic curve and a planar subset. We derive sharp asymptotic estimates in assessing the cloaking performances of the two constructions in terms of the regularization parameters and the geometries of the cloaking devices. The first construction yields an approximate full-cloak, whereas the second construction yields an approximate partial-cloak. Moreover, by incorporating properly chosen conducting layers, both cloaking constructions are capable of nearly cloaking arbitrary EM contents. This work complements the existing results in Ammari et al. (SIAM J Appl Math 73:2055-2076, 2013), Bao and Liu (SIAM J Appl Math 74:724-742, 2014), Bao et al. (J Math Pure Appl (9) 101:716-733, 2014) on approximate EM cloaks with the generating set being a singular point, and it also extends Deng et al. (On regularized full- and partial-cloaks in acoustic scat- tering. Preprint, arXiv:1502.01174, 2015), Li et al. (Commun Math Phys, 335:671-712, 2015) on regularized full and partial cloaks for acoustic waves governed by the Helmholtz system to the more challenging EM case governed by the full Maxwell system.

  11. An Object-Independent ENZ Metamaterial-Based Wideband Electromagnetic Cloak.

    Science.gov (United States)

    Islam, Sikder Sunbeam; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

    2016-09-16

    A new, metamaterial-based electromagnetic cloaking operation is proposed in this study. The metamaterial exhibits a sharp transmittance in the C-band of the microwave spectrum with negative effective property of permittivity at that frequency. Two metal arms were placed on an FR-4 substrate to construct a double-split-square shape structure. The size of the resonator was maintained to achieve the effective medium property of the metamaterial. Full wave numerical simulation was performed to extract the reflection and transmission coefficients for the unit cell. Later on, a single layer square-shaped cloak was designed using the proposed metamaterial unit cell. The cloak hides a metal cylinder electromagnetically, where the material exhibits epsilon-near-zero (ENZ) property. Cloaking operation was demonstrated adopting the scattering-reduction technique. The measured result was provided to validate the characteristics of the metamaterial and the cloak. Some object size- and shape-based analyses were performed with the cloak, and a common cloaking region was revealed over more than 900 MHz in the C-band for the different objects.

  12. An Object-Independent ENZ Metamaterial-Based Wideband Electromagnetic Cloak

    Science.gov (United States)

    Islam, Sikder Sunbeam; Faruque, Mohammad Rashed Iqbal; Islam, Mohammad Tariqul

    2016-01-01

    A new, metamaterial-based electromagnetic cloaking operation is proposed in this study. The metamaterial exhibits a sharp transmittance in the C-band of the microwave spectrum with negative effective property of permittivity at that frequency. Two metal arms were placed on an FR-4 substrate to construct a double-split-square shape structure. The size of the resonator was maintained to achieve the effective medium property of the metamaterial. Full wave numerical simulation was performed to extract the reflection and transmission coefficients for the unit cell. Later on, a single layer square-shaped cloak was designed using the proposed metamaterial unit cell. The cloak hides a metal cylinder electromagnetically, where the material exhibits epsilon-near-zero (ENZ) property. Cloaking operation was demonstrated adopting the scattering-reduction technique. The measured result was provided to validate the characteristics of the metamaterial and the cloak. Some object size- and shape-based analyses were performed with the cloak, and a common cloaking region was revealed over more than 900 MHz in the C-band for the different objects. PMID:27634456

  13. Detecting electromagnetic cloaks using backward-propagating waves

    KAUST Repository

    Salem, Mohamed

    2011-08-01

    A novel approach for detecting transformation-optics invisibility cloaks is proposed. The detection method takes advantage of the unusual backward-propagation characteristics of recently reported beams and pulses to induce electromagnetic scattering from the cloak. Even though waves with backward-propagating energy flux cannot penetrate the cloaking shell and interact with the cloaked objects (i.e., they do not make the cloaked object visible), they provide a mechanism for detecting the presence of cloaks. © 2011 IEEE.

  14. Electromagnetic Detection of a Perfect Carpet Cloak

    Science.gov (United States)

    Shi, Xihang; Gao, Fei; Lin, Xiao; Zhang, Baile

    2015-01-01

    It has been shown that a spherical invisibility cloak originally proposed by Pendry et al. can be electromagnetically detected by shooting a charged particle through it, whose underlying mechanism stems from the asymmetry of transformation optics applied to motions of photons and charges [PRL 103, 243901 (2009)]. However, the conceptual three-dimensional invisibility cloak that exactly follows specifications of transformation optics is formidably difficult to implement, while the simplified cylindrical cloak that has been experimentally realized is inherently visible. On the other hand, the recent carpet cloak model has acquired remarkable experimental development, including a recently demonstrated full-parameter carpet cloak without any approximation in the required constitutive parameters. In this paper, we numerically investigate the electromagnetic radiation from a charged particle passing through a perfect carpet cloak and propose an experimentally verifiable model to demonstrate symmetry breaking of transformation optics. PMID:25997798

  15. Isotropic-medium three-dimensional cloaks for acoustic and electromagnetic waves

    CERN Document Server

    Urzhumov, Yaroslav; Smith, David R; 10.1063/1.3691242

    2012-01-01

    We propose a generalization of the two-dimensional eikonal-limit cloak derived from a conformal transformation to three dimensions. The proposed cloak is a spherical shell composed of only isotropic media; it operates in the transmission mode and requires no mirror or ground plane. Unlike the well-known omnidirectional spherical cloaks, it may reduce visibility of an arbitrary object only for a very limited range of observation angles. In the short-wavelength limit, this cloaking structure restores not only the trajectories of incident rays, but also their phase, which is a necessary ingredient to complete invisibility. Both scalar-wave (acoustic) and transverse vector-wave (electromagnetic) versions are presented.

  16. Designing near-perfect invisibility cloaks

    DEFF Research Database (Denmark)

    Qiu, Min; Yan, Wei; Yan, Min

    2008-01-01

    Using the theory of transformation optics, practical cylindrical invisibility cloaks can be devised to conceal objects from detection at a targeted wavelength.......Using the theory of transformation optics, practical cylindrical invisibility cloaks can be devised to conceal objects from detection at a targeted wavelength....

  17. Macroscopic invisibility cloaking of visible light

    DEFF Research Database (Denmark)

    Chen, Xianzhong; Luo, Y.; Zhang, Jingjing;

    2011-01-01

    to a few wavelengths. Here, we report the first realization of a macroscopic volumetric invisibility cloak constructed from natural birefringent crystals. The cloak operates at visible frequencies and is capable of hiding, for a specific light polarization, three-dimensional objects of the scale...

  18. Non-Euclidean cloaking for light waves

    CERN Document Server

    Tyc, Tomas; Chan, Che Ting; Leonhardt, Ulf

    2009-01-01

    Non-Euclidean geometry combined with transformation optics has recently led to the proposal of an invisibility cloak that avoids optical singularities and therefore can work, in principle, in a broad band of the spectrum [U. Leonhardt and T. Tyc, Science 323, 110 (2009)]. Such a cloak is perfect in the limit of geometrical optics, but not in wave optics. Here we analyze, both analytically and numerically, full wave propagation in non-Euclidean cloaking. We show that the cloaking device performs remarkably well even in a regime beyond geometrical optics where the device is comparable in size with the wavelength. In particular, the cloak is nearly perfect for a spectrum of frequencies that are related to spherical harmonics. We also show that for increasing wavenumber the device works increasingly better, approaching perfect behavior in the limit of geometrical optics.

  19. Fourier analysis: from cloaking to imaging

    Science.gov (United States)

    Wu, Kedi; Cheng, Qiluan; Wang, Guo Ping

    2016-04-01

    Regarding invisibility cloaks as an optical imaging system, we present a Fourier approach to analytically unify both Pendry cloaks and complementary media-based invisibility cloaks into one kind of cloak. By synthesizing different transfer functions, we can construct different devices to realize a series of interesting functions such as hiding objects (events), creating illusions, and performing perfect imaging. In this article, we give a brief review on recent works of applying Fourier approach to analysis invisibility cloaks and optical imaging through scattering layers. We show that, to construct devices to conceal an object, no constructive materials with extreme properties are required, making most, if not all, of the above functions realizable by using naturally occurring materials. As instances, we experimentally verify a method of directionally hiding distant objects and create illusions by using all-dielectric materials, and further demonstrate a non-invasive method of imaging objects completely hidden by scattering layers.

  20. Transformation thermodynamics and heat cloaking: a review

    Science.gov (United States)

    Raza, Muhammad; Liu, Yichao; Lee, El Hang; Ma, Yungui

    2016-04-01

    This article is a review of the advances and progresses in the field of heat cloaking which is being realized using metamaterials. Heat cloaking has been a particularly important subject of study due to its potential multidimensional applications. The process which manipulates the heat flux in such a way that it can neither enter into the cloaked region nor be distorted outside is called thermal cloaking. Transformation optics has made the hitherto inconceivable advancements in the field of thermodynamics possible with the remarkable assistance of metamaterials. In this article we present a review of the work done in the field of heat cloaking, its progress and outlook. We discuss the theoretical and experimental studies, models, design managements, implementations and behaviors of thermal invisibility cloaking and related devices. This review is intended to help further develop practical and applicable concepts, examine fabrication techniques for a variety of different invisibility cloaking devices and systems, and to pave a way for the new avenues leading to new future technologies.

  1. A temporal cloak at telecommunication data rate.

    Science.gov (United States)

    Lukens, Joseph M; Leaird, Daniel E; Weiner, Andrew M

    2013-06-13

    Through advances in metamaterials--artificially engineered media with exotic properties, including negative refractive index--the once fanciful invisibility cloak has now assumed a prominent place in scientific research. By extending these concepts to the temporal domain, investigators have recently described a cloak which hides events in time by creating a temporal gap in a probe beam that is subsequently closed up; any interaction which takes place during this hole in time is not detected. However, these results are limited to isolated events that fill a tiny portion of the temporal period, giving a fractional cloaking window of only about 10(-4) per cent at a repetition rate of 41 kilohertz (ref. 15)--which is much too low for applications such as optical communications. Here we demonstrate another technique for temporal cloaking, which operates at telecommunication data rates and, by exploiting temporal self-imaging through the Talbot effect, hides optical data from a receiver. We succeed in cloaking 46 per cent of the entire time axis and conceal pseudorandom digital data at a rate of 12.7 gigabits per second. This potential to cloak real-world messages introduces temporal cloaking into the sphere of practical application, with immediate ramifications in secure communications.

  2. Theory of diffusive light scattering cancellation cloaking

    CERN Document Server

    Farhat, Mohamed; Guenneau, Sebastien; Bagci, Hakan; Salama, Khaled Nabil; Alu, Andrea

    2016-01-01

    We report on a new concept of cloaking objects in diffusive light regime using the paradigm of the scattering cancellation and mantle cloaking techniques. We show numerically that an object can be made completely invisible to diffusive photon density waves, by tailoring the diffusivity constant of the spherical shell enclosing the object. This means that photons' flow outside the object and the cloak made of these spherical shells behaves as if the object were not present. Diffusive light invisibility may open new vistas in hiding hot spots in infrared thermography or tissue imaging.

  3. Enhancement of non-resonant dielectric cloaks using anisotropic composites

    CERN Document Server

    Takezawa, Akihiro

    2014-01-01

    The effectiveness of homogenized anisotropic materials in non-resonant dielectric multilayer cloaking is studied. Because existing multilayer cloaking by isotropic materials can be regarded as homogenous anisotropic cloaking from a macroscopic view, they can be efficiently designed by handling the physical properties of anisotropic materials directly. Anisotropic properties can be realized in two-phase composites if the physical properties of the material are within appropriate bounds. The optimized anisotropic physical properties are identified by a numerical optimization technique based on a full-wave simulation using the finite element method. The cloaking performance measured by the total scattering width is improved by about 10% compared with existing multilayer cloaking by isotropic materials in eight-layer cylindrical cloaking materials. The same performance with eight-layer cloaking by isotropic materials is achieved by three-layer cloaking using anisotropic materials. Cloaking with a about 50% reduct...

  4. Numerical design of FSHL-based approximate cloaks with arbitrary shapes

    Science.gov (United States)

    Wang, Qi; Hou, Yanren; Li, Jingzhi

    2017-03-01

    This paper considers numerical design of finite sound-hard lining (FSHL)-based approximate cloaks with arbitrary shapes. Regarding the complexity of the shape, two new approaches are proposed to design the transformation map from the virtual space to the physical space via transformation optics. For star-shaped geometry, we propose an explicit global transformation map which can be easily differentiated and inverted. For more general shapes, an Initialize-Untangle-Extend (IUE) approach is initiated to build locally piecewise differentiable deformations, which can be locally inverted with the help of an approximate triangulation. With the locally piecewise-constructed transformation, the parameters of acoustic scattering models in physical space can be determined in both approaches based on the transformation invariance of the Helmholtz system. Then the cloaking effects for an arbitrary shape FSHL-based cloak can be realized following Li et al. (2012) [5]. Extensive numerical experiments are presented to illustrate both the effectiveness of cloak design and the efficiency of the proposed FSHL-based cloaks with arbitrary shapes.

  5. Design of optical cloaks and illusion devices along a circumferential direction in curvilinear coordinates

    Science.gov (United States)

    Chen, Tungyang; Yu, Shang-Ru

    2010-11-01

    We propose a cloaking and illusion device of circumferential topology based on the concept of transformation optics. The device is capable to cloak an object and/or simultaneously generate illusion images along a circumferential direction in curvilinear orthogonal coordinates. This feature allows us to construct multiple illusions in different ways, irrespective of the profile and direction of incident wave. Particularly when the device is served as a building brick of a larger device, one can generate a circumferential array of illusions in a periodic or any preferred pattern. We demonstrate the effectiveness of the proposed illusion devices by carrying out full wave simulations based on finite element calculations.

  6. Macroscopic Invisible Cloak for Visible Light

    CERN Document Server

    Zhang, Baile; Liu, Xiaogang; Barbastathis, George

    2011-01-01

    Invisibility cloaks, a subject that usually occurs in science fiction and myths, have attracted wide interest recently because of their possible realization. The biggest challenge to true invisibility is known to be the cloaking of a macroscopic object in the broad range of wavelengths visible to the human eye. Here we experimentally solve this problem by incorporating the principle of transformation optics into a conventional optical lens fabrication with low-cost materials and simple manufacturing techniques. A transparent cloak made of two pieces of calcite is created. This cloak is able to conceal a macroscopic object with a maximum height of 2 mm, larger than 3500 free-space-wavelength, inside a transparent liquid environment. Its working bandwidth encompassing red, green and blue light is also demonstrated.

  7. Permittivity and permeability tensors for cloaking applications

    CERN Document Server

    Choudhury, Balamati; Jha, Rakesh Mohan

    2016-01-01

    This book is focused on derivations of analytical expressions for stealth and cloaking applications. An optimal version of electromagnetic (EM) stealth is the design of invisibility cloak of arbitrary shapes in which the EM waves can be controlled within the cloaking shell by introducing a prescribed spatial variation in the constitutive parameters. The promising challenge in design of invisibility cloaks lies in the determination of permittivity and permeability tensors for all the layers. This book provides the detailed derivation of analytical expressions of the permittivity and permeability tensors for various quadric surfaces within the eleven Eisenhart co-ordinate systems. These include the cylinders and the surfaces of revolutions. The analytical modeling and spatial metric for each of these surfaces are provided along with their tensors. This mathematical formulation will help the EM designers to analyze and design of various quadratics and their hybrids, which can eventually lead to design of cloakin...

  8. A Cloaking Device for Transiting Planets

    CERN Document Server

    Kipping, David M

    2016-01-01

    The transit method is presently the most successful planet discovery and characterization tool at our disposal. Other advanced civilizations would surely be aware of this technique and appreciate that their home planet's existence and habitability is essentially broadcast to all stars lying along their ecliptic plane. We suggest that advanced civilizations could cloak their presence, or deliberately broadcast it, through controlled laser emission. Such emission could distort the apparent shape of their transit light curves with relatively little energy, due to the collimated beam and relatively infrequent nature of transits. We estimate that humanity could cloak the Earth from Kepler-like broadband surveys using an optical monochromatic laser array emitting a peak power of about 30 MW for roughly 10 hours per year. A chromatic cloak, effective at all wavelengths, is more challenging requiring a large array of tunable lasers with a total power of approximately 250 MW. Alternatively, a civilization could cloak ...

  9. Active Invisibility Cloaks in One Dimension

    OpenAIRE

    2015-01-01

    PHYSICAL REVIEW A 91, 063812 (2015) Active invisibility cloaks in one dimension Ali Mostafazadeh* Departments of Physics and Mathematics, Koc¸ University, Sarıyer 34450, Istanbul, Turkey (Received 19 March 2015; published 12 June 2015) We outline a general method of constructing finite-range cloaking potentials which render a given finite-range real or complex potential, v(x), unidirectionally reflectionless or invisible at a wave number, k0, of our choice.We give explici...

  10. Transformation thermodynamics: cloaking and concentrating heat flux.

    Science.gov (United States)

    Guenneau, Sebastien; Amra, Claude; Veynante, Denis

    2012-03-26

    We adapt tools of transformation optics, governed by a (elliptic) wave equation, to thermodynamics, governed by the (parabolic) heat equation. We apply this new concept to an invibility cloak in order to thermally protect a region (a dead core) and to a concentrator to focus heat flux in a small region. We finally propose a multilayered cloak consisting of 20 homogeneous concentric layers with a piecewise constant isotropic diffusivity working over a finite time interval (homogenization approach).

  11. Structural systems for highrise buildings

    OpenAIRE

    Sobek, Werner

    1985-01-01

    The report was written in the United States under the first Fazlur R. Khan Fellowship in 1984 and it was completed in Germany afterwards. "Highrise Buildings" was selected by the author as the draft-title for the activities during the fellowship. Under this theme the author studied the single aspects of highrise buildings as for example planning methods, architectural considerations, structuraI systems. This was done by working at the offices of Skidmore, Owings and Herrill in Chicago and San...

  12. Elliptical metasurfaces for cloaking and antenna applications at microwave and terahertz frequencies

    Science.gov (United States)

    Mehrpourbernety, Hossein

    One of the interesting applications of metamaterials is the phenomenon of electromagnetic invisibility and cloaking, which implies the suppression of bistatic scattering width of a given object, independent of incident and observation angles. In this regard, diverse techniques have been proposed to analyze and design electromagnetic cloak structures, including transformation optics, anomalous resonance methods, transmission-line networks, and plasmonic cloaking, among others. A common drawback of all these methods is that they rely on bulk materials, which are difficult to realize in practice. To overcome this issue, the mantle cloaking method has been proposed, which utilizes an ultrathin metasurface that provides anti-phase surface currents to reduce the scattering dominant mode of a given object. Recently, an analytical model has been proposed to cloak dielectric and conducting cylindrical objects realized with printed and slotted arrays at microwave frequencies. At low-terahertz (THz) frequencies, one of the promising materials to realize the required metasurface is graphene. In this regard, a graphene monolayer, characterized by inductive reactance, has been proposed to cloak dielectric planar and cylindrical objects. Then, it has been shown that a metasurface made of graphene nanopatches owns dual capacitive/inductive inductance and can be used to cloak both dielectric and conducting cylindrical objects at low-THz frequencies. So far, planar and cylindrical dielectric and conducting structures have been studied. In our study, we have extended the concept and presented an accurate analytical approach to investigate the cloaking of two-dimensional (2-D) elliptical objects including infinite dielectric elliptical cylinders using graphene monolayer; metallic elliptical cylinders, and also, as a special case, 2-D metallic strips using a nanostructured graphene patch array at low-THz frequencies. We have also obtained the results for cloaking of ellipses at

  13. Towards all-dielectric, polarization-independent optical cloaks

    DEFF Research Database (Denmark)

    Andkjær, Jacob Anders; Mortensen, N. Asger; Sigmund, Ole

    2012-01-01

    Fully enclosing, all-dielectric cloaks working for both E-z and H-z polarizations simultaneously are presented in this letter. The cloaks are effective for two antiparallel angles of incidence, and the layout of standard dielectric material in the cloak is determined by topology optimization...

  14. Optical phase cloaking of 700 nm light waves in the far field by a three-dimensional carpet cloak.

    Science.gov (United States)

    Ergin, Tolga; Fischer, Joachim; Wegener, Martin

    2011-10-21

    Transformation optics is a design tool that connects the geometry of space and propagation of light. Invisibility cloaking is a corresponding benchmark example. Recent experiments at optical frequencies have demonstrated cloaking for the light amplitude only. In this Letter, we demonstrate far-field cloaking of the light phase by interferometric microscope-imaging experiments on the previously introduced three-dimensional carpet cloak at 700 nm wavelength and for arbitrary polarization of light.

  15. Broadband surface-wave transformation cloak

    Science.gov (United States)

    Xu, Su; Xu, Hongyi; Gao, Hanhong; Jiang, Yuyu; Yu, Faxin; Joannopoulos, John D.; Soljačić, Marin; Chen, Hongsheng; Sun, Handong; Zhang, Baile

    2015-01-01

    Guiding surface electromagnetic waves around disorder without disturbing the wave amplitude or phase is in great demand for modern photonic and plasmonic devices, but is fundamentally difficult to realize because light momentum must be conserved in a scattering event. A partial realization has been achieved by exploiting topological electromagnetic surface states, but this approach is limited to narrow-band light transmission and subject to phase disturbances in the presence of disorder. Recent advances in transformation optics apply principles of general relativity to curve the space for light, allowing one to match the momentum and phase of light around any disorder as if that disorder were not there. This feature has been exploited in the development of invisibility cloaks. An ideal invisibility cloak, however, would require the phase velocity of light being guided around the cloaked object to exceed the vacuum speed of light—a feat potentially achievable only over an extremely narrow band. In this work, we theoretically and experimentally show that the bottlenecks encountered in previous studies can be overcome. We introduce a class of cloaks capable of remarkable broadband surface electromagnetic waves guidance around ultrasharp corners and bumps with no perceptible changes in amplitude and phase. These cloaks consist of specifically designed nonmagnetic metamaterials and achieve nearly ideal transmission efficiency over a broadband frequency range from 0+ to 6 GHz. This work provides strong support for the application of transformation optics to plasmonic circuits and could pave the way toward high-performance, large-scale integrated photonic circuits. PMID:26056299

  16. Structured building model reduction toward parallel simulation

    Energy Technology Data Exchange (ETDEWEB)

    Dobbs, Justin R. [Cornell University; Hencey, Brondon M. [Cornell University

    2013-08-26

    Building energy model reduction exchanges accuracy for improved simulation speed by reducing the number of dynamical equations. Parallel computing aims to improve simulation times without loss of accuracy but is poorly utilized by contemporary simulators and is inherently limited by inter-processor communication. This paper bridges these disparate techniques to implement efficient parallel building thermal simulation. We begin with a survey of three structured reduction approaches that compares their performance to a leading unstructured method. We then use structured model reduction to find thermal clusters in the building energy model and allocate processing resources. Experimental results demonstrate faster simulation and low error without any interprocessor communication.

  17. Advanced analysis for structural steel building design

    Institute of Scientific and Technical Information of China (English)

    Wai Fah CHEN

    2008-01-01

    The 2005 AISC LRFD Specifications for Structural Steel Buildings are making it possible for designers to recognize explicitly the structural resistance provided within the elastic and inelastic ranges of beha-vior and up to the maximum load limit state. There is an increasing awareness of the need for practical second-order analysis approaches for a direct determination of overall structural system response. This paper attempts to present a simple, concise and reasonably comprehens-ive introduction to some of the theoretical and practical approaches which have been used in the traditional and modern processes of design of steel building structures.

  18. Optimized invisibility cloaks from the Logarithm conformal mapping

    Science.gov (United States)

    Zhu, Chunhui; Liu, Lijun; Song, Zhengyong; Liu, Qing Huo

    2016-12-01

    Invisibility cloaks designed from the coordinate transformation method have attracted increasing interest recently. Conformal transformation optics scheme leads to cloaks that possess isotopic media, thus provides a prospective way to facilitate easier realization. Reducing the maximum value of the refractive index required by the cloaks is very important in practical imple- mentation. This letter studies on how the parameters in the logarithm conformal mapping control the cloaking effect. The optimized invisibility cloaks are designed. The maximum values of the refractive index required from the first kind and the second kind of logarithm conformal mappings are reduced to 9.779 and 12.936, respectively.

  19. Transmission-line networks cloaking objects from electromagnetic fields

    CERN Document Server

    Alitalo, Pekka; Jylhä, Liisi; Venermo, Jukka; Tretyakov, Sergei

    2007-01-01

    We consider a novel method of cloaking objects from the surrounding electromagnetic fields in the microwave region. The method is based on transmission-line networks that simulate the wave propagation in the medium surrounding the cloaked object. The electromagnetic fields from the surrounding medium are coupled into the transmission-line network that guides the waves through the cloak thus leaving the cloaked object undetected. The cloaked object can be an array or interconnected mesh of small inclusions that fit inside the transmission-line network.

  20. Flow stabilization with active hydrodynamic cloaks

    CERN Document Server

    Urzhumov, Yaroslav A; 10.1103/PhysRevE.86.056313

    2012-01-01

    We demonstrate that fluid flow cloaking solutions based on active hydrodynamic metamaterials exist for two-dimensional flows past a cylinder in a wide range of Reynolds numbers, up to approximately 200. Within the framework of the classical Brinkman equation for homogenized porous flow, we demonstrate using two different methods that such cloaked flows can be dynamically stable for $Re$ in the range 5-119. The first, highly efficient, method is based on a linearization of the Brinkman-Navier-Stokes equation and finding the eigenfrequencies of the least stable eigen-perturbations; the second method is a direct, numerical integration in the time domain. We show that, by suppressing the Karman vortex street in the weekly turbulent wake, porous flow cloaks can raise the critical Reynolds number up to about 120, or five times greater than for a bare, uncloaked cylinder.

  1. Illusions and Cloaks for Surface Waves

    Science.gov (United States)

    McManus, T. M.; Valiente-Kroon, J. A.; Horsley, S. A. R.; Hao, Y.

    2014-08-01

    Ever since the inception of Transformation Optics (TO), new and exciting ideas have been proposed in the field of electromagnetics and the theory has been modified to work in such fields as acoustics and thermodynamics. The most well-known application of this theory is to cloaking, but another equally intriguing application of TO is the idea of an illusion device. Here, we propose a general method to transform electromagnetic waves between two arbitrary surfaces. This allows a flat surface to reproduce the scattering behaviour of a curved surface and vice versa, thereby giving rise to perfect optical illusion and cloaking devices, respectively. The performance of the proposed devices is simulated using thin effective media with engineered material properties. The scattering of the curved surface is shown to be reproduced by its flat analogue (for illusions) and vice versa for cloaks.

  2. Design, implementation, and extension of thermal invisibility cloaks

    Directory of Open Access Journals (Sweden)

    Youming Zhang

    2015-05-01

    Full Text Available A thermal invisibility cloak, as inspired by optical invisibility cloaks, is a device which can steer the conductive heat flux around an isolated object without changing the ambient temperature distribution so that the object can be “invisible” to external thermal environment. While designs of thermal invisibility cloaks inherit previous theories from optical cloaks, the uniqueness of heat diffusion leads to more achievable implementations. Thermal invisibility cloaks, as well as the variations including thermal concentrator, rotator, and illusion devices, have potentials to be applied in thermal management, sensing and imaging applications. Here, we review the current knowledge of thermal invisibility cloaks in terms of their design and implementation in cloaking studies, and their extension as other functional devices.

  3. Building a Structural Model: Parameterization and Structurality

    Directory of Open Access Journals (Sweden)

    Michel Mouchart

    2016-04-01

    Full Text Available A specific concept of structural model is used as a background for discussing the structurality of its parameterization. Conditions for a structural model to be also causal are examined. Difficulties and pitfalls arising from the parameterization are analyzed. In particular, pitfalls when considering alternative parameterizations of a same model are shown to have lead to ungrounded conclusions in the literature. Discussions of observationally equivalent models related to different economic mechanisms are used to make clear the connection between an economically meaningful parameterization and an economically meaningful decomposition of a complex model. The design of economic policy is used for drawing some practical implications of the proposed analysis.

  4. Cloaking and imaging at the same time

    CERN Document Server

    Wu, Qiannan; Chen, Huanyang

    2012-01-01

    In this letter, we propose a conceptual device to perform subwavelength imaging with positive refraction. The key to this proposal is that a drain is no longer a must for some cases. What's more, this device is an isotropic omnidirectional cloak with a perfect electric conductor hiding region and shows versatile illusion optical effects. Numerical simulations are performed to verify the functionalities.

  5. Cloaking and imaging at the same time

    Science.gov (United States)

    Wu, Qiannan; Xu, Yadong; Li, Hui; Chen, Huanyang

    2013-02-01

    In this letter, we propose a conceptual device to perform good imaging with positive refraction. At the same time, this device is an isotropic omnidirectional cloak with a perfect electric conductor hiding region and shows versatile illusion optical effects. Numerical simulations are performed to verify the functionalities.

  6. Aluminium building and civil engineering structures

    NARCIS (Netherlands)

    Soetens, F.; Mennink, J.

    1999-01-01

    The design of aluminium structures in building and civil engineering applications is different from designing in traditional materials. This difference is based on the physical and mechanical properties of the material and the freedom of cross-sectional shape provided by the extrusion manufacturing

  7. On Directionality of Phrase Structure Building

    Science.gov (United States)

    Chesi, Cristiano

    2015-01-01

    Minimalism in grammatical theorizing (Chomsky in "The minimalist program." MIT Press, Cambridge, 1995) led to simpler linguistic devices and a better focalization of the core properties of the structure building engine: a lexicon and a free (recursive) phrase formation operation, dubbed Merge, are the basic components that serve in…

  8. Two-Dimensional (2D) Polygonal Electromagnetic Cloaks

    Institute of Scientific and Technical Information of China (English)

    LI Chao; YAO Kan; LI Fang

    2009-01-01

    Transformation optics offers remarkable control over electromagnetic fields and opens an exciting gateway to design 'invisible cloak devices' recently.We present an important class of two-dimensional (2D) cloaks with polygon geometries.Explicit expressions of transformed medium parameters are derived with their unique properties investigated.It is found that the elements of diagonalized permittivity tensors are always positive within an irregular polygon cloak besides one element diverges to plus infinity and the other two become zero at the inner boundary.At most positions,the principle axes of permittivity tensors do not align with position vectors.An irregular polygon cloak is designed and its invisibility to external electromagnetic waves is numerically verified.Since polygon cloaks can be tailored to resemble any objects,the transformation is finally generalized to the realization of 2D cloaks with arbitrary geometries.

  9. Yttrium oxide based three dimensional metamaterials for visible light cloaking

    Science.gov (United States)

    Rai, Pratyush; Kumar, Prashanth S.; Varadan, Vijay K.; Ruffin, Paul; Brantley, Christina; Edwards, Eugene

    2014-04-01

    Metamaterial with negative refractive index is the key phenomenon behind the concept of a cloaking device to hide an object from light in visible spectrum. Metamaterials made of two and three dimensional lattices of periodically placed electromagnetic resonant cells can achieve absorption and propagation of incident electromagnetic radiation as confined electromagnetic fields confined to a waveguide as surface plasmon polaritons, which can be used for shielding an object from in-tune electromagnetic radiation. The periodicity and dimensions of resonant cavity determine the frequency, which are very small as compared to the wavelength of incident light. Till now the phenomena have been demonstrated only for lights in near infrared spectrum. Recent advancements in fabrication techniques have made it possible to fabricate array of three dimensional nanostructures with cross-sections as small as 25 nm that are required for negative refractive index for wavelengths in visible light spectrum of 400-700 nm and for wider view angle. Two types of metamaterial designs, three dimensional concentric split ring and fishnet, are considered. Three dimensional structures consisted of metal-dielectric-metal stacks. The metal is silver and dielectric is yttrium oxide, other than conventional materials such as FR4 and Duroid. High κ dielectric and high refractive index as well as large crystal symmetry of Yttrium oxide has been investigated as encapsulating medium. Dependence of refractive index on wavelength and bandwidth of negative refractive index region are analyzed for application towards cloaking from light in visible spectrum.

  10. The design of metamaterial cloaks embedded in anisotropic medium

    Institute of Scientific and Technical Information of China (English)

    Ma Hua; Qu Shao-Bo; Xu Zhuo; Zhang Jie-Qiu; Wang Jia-Fu

    2009-01-01

    By using coordinate transformation method, this paper obtains an useful equation of designing meta-material cloaks embedded in anisotropic medium. This equation is the generalization of what was introduced early by Pendry et al (2006 Science 312 1780) and can be more widely used. As an example of its applications, this paper deduces the material parameter equation for cylinder cloaks embedded in anisotropic medium, and then offers the numerical simulation. The results show that such a cylinder cloak has perfect cloaking performance and therefore verifies the method proposed in this paper.

  11. Topology optimized low-contrast all-dielectric optical cloak

    DEFF Research Database (Denmark)

    Andkjær, Jacob Anders; Sigmund, Ole

    2011-01-01

    A systematic methodology for designing low-contrast all-dielectric cloaks operating in the optical range is presented. Topology optimization is used to find the layout of standard dielectric material that minimizes the norm of the scattered field in the surroundings of the cloak. Rotational...... symmetries are exploited to optimize for multiple angles based on the solution for a single angle of incidence. For a few discrete angles of incidences (1-4) the cloaking is shown to be nearly perfect in a limited frequency range, and even for a rotational symmetric design, cloak and object appear smaller...

  12. Electromagnetic Reciprocal Cloak with Only Axial Material Parameter Spatially Variant

    Directory of Open Access Journals (Sweden)

    Jing Jing Yang

    2012-01-01

    Full Text Available Reciprocal cloak is an intriguing metamaterial device, in which a hidden antenna or a sensor can receive electromagnetic irradiation from the outside but its presence will not be detected. Based on transformation optics, a cylindrical electromagnetic reciprocal cloak with only axial parameter varying with radius is designed and validated by full wave simulation. When two dispersive reciprocal cloaks are put together, they do not interfere with each other. Our work demonstrates the electromagnetic compatibility (EMC ability of the reciprocal cloak which is very important in multi antenna and sensor design.

  13. Optical Möbius strips and twisted ribbon cloaks.

    Science.gov (United States)

    Freund, Isaac

    2014-02-15

    Optical Möbius strips that surround points of circular polarization, C points, in a generic three-dimensional optical field are cloaked by lines of twisted ribbons attached to the C points. When cloaking occurs, the observable signed twist index that counts the number of half-twists (one or three), and also measures the handedness (right or left), of a generic Möbius strip is determined by the twisted ribbon cloaks. Although some cloaks can be detached, they can never all be removed.

  14. Cell Membrane-Cloaked Nanoparticles for Targeted Therapeutics

    Science.gov (United States)

    Luk, Brian Tsengchi

    The advent of nanoparticle-based delivery systems has made a significant impact on clinical patient outcomes. In recent decades, myriad nanoparticle-based therapeutic agents have been developed for the treatment and management of ailments such as cancer, diabetes, pain, bacterial infections, and asthma, among many others. Nanotherapeutics offer many distinct advantages over conventional free drug formulations. For example, nanoparticles are able to accumulate at tumor sites by extravasation through leaky vasculature at tumor sites via the enhanced permeability and retention (EPR) effect; nanoparticles can also be tailored to have desirable characteristics, such as prolonged circulation in the blood stream, improved drug encapsulation, and sustained or triggered drug release. Currently, a growing number of nanoformulations with favorable pharmacological profiles and promising efficacy are being used in clinical trials for the treatment of various cancers. Building on the success of these encouraging clinical results, new engineering strategies have emerged that combine synthetic nanoparticles with natural biomaterials to create nature-inspired biomimetic delivery systems. The work presented in this dissertation focuses on the biointerfacing between synthetic and natural materials, namely in the manifestation of cell membrane-coated nanoparticles. By exploiting the natural functionalities of source cell membranes, cell membrane-cloaked nanoparticles have huge potential in the delivery of therapeutic agents for a variety of applications. The first portion of this thesis will focus on understanding the fundamentals underlying cell membrane coating on synthetic nanoparticles. First introduced in 2011, cell membrane-cloaked nanoparticles showed immediate promise in drug delivery applications, but further understanding was necessary to be able to harness the full potential of the membrane coating platform. The first section provides further insight into the interfacial

  15. A cloaking device for transiting planets

    Science.gov (United States)

    Kipping, David M.; Teachey, Alex

    2016-06-01

    The transit method is presently the most successful planet discovery and characterization tool at our disposal. Other advanced civilizations would surely be aware of this technique and appreciate that their home planet's existence and habitability is essentially broadcast to all stars lying along their ecliptic plane. We suggest that advanced civilizations could cloak their presence, or deliberately broadcast it, through controlled laser emission. Such emission could distort the apparent shape of their transit light curves with relatively little energy, due to the collimated beam and relatively infrequent nature of transits. We estimate that humanity could cloak the Earth from Kepler-like broad-band surveys using an optical monochromatic laser array emitting a peak power of ˜30 MW for ˜10 hours per year. A chromatic cloak, effective at all wavelengths, is more challenging requiring a large array of tunable lasers with a total power of ˜250 MW. Alternatively, a civilization could cloak only the atmospheric signatures associated with biological activity on their world, such as oxygen, which is achievable with a peak laser power of just ˜160 kW per transit. Finally, we suggest that the time of transit for optical Search for Extraterrestrial Intelligence (SETI) is analogous to the water-hole in radio SETI, providing a clear window in which observers may expect to communicate. Accordingly, we propose that a civilization may deliberately broadcast their technological capabilities by distorting their transit to an artificial shape, which serves as both a SETI beacon and a medium for data transmission. Such signatures could be readily searched in the archival data of transit surveys.

  16. Determining building interior structures using compressive sensing

    Science.gov (United States)

    Lagunas, Eva; Amin, Moeness G.; Ahmad, Fauzia; Nájar, Montse

    2013-04-01

    We consider imaging of the building interior structures using compressive sensing (CS) with applications to through-the-wall imaging and urban sensing. We consider a monostatic synthetic aperture radar imaging system employing stepped frequency waveform. The proposed approach exploits prior information of building construction practices to form an appropriate sparse representation of the building interior layout. We devise a dictionary of possible wall locations, which is consistent with the fact that interior walls are typically parallel or perpendicular to the front wall. The dictionary accounts for the dominant normal angle reflections from exterior and interior walls for the monostatic imaging system. CS is applied to a reduced set of observations to recover the true positions of the walls. Additional information about interior walls can be obtained using a dictionary of possible corner reflectors, which is the response of the junction of two walls. Supporting results based on simulation and laboratory experiments are provided. It is shown that the proposed sparsifying basis outperforms the conventional through-the-wall CS model, the wavelet sparsifying basis, and the block sparse model for building interior layout detection.

  17. The boundary conditions for point transformed electromagnetic invisibility cloaks

    Energy Technology Data Exchange (ETDEWEB)

    Weder, Ricardo [Departamento de Metodos Matematicos y Numericos, Instituto de Investigaciones en Matematicas Aplicadas y en Sistemas, Universidad Nacional Autonoma de Mexico, Apartado Postal 20-726, Mexico DF 01000 (Mexico)], E-mail: weder@servidor.unam.mx

    2008-10-17

    In this paper we study point transformed electromagnetic invisibility cloaks in transformation media that are obtained by transformation from general anisotropic media. We assume that there are several point transformed electromagnetic cloaks located in different points in space. Our results apply in particular to the first-order invisibility cloaks introduced by Pendry et al and to the high-order invisibility cloaks introduced by Hendi et al and by Cai et al. We identify the appropriate cloaking boundary conditions that the solutions of Maxwell equations have to satisfy at the outside, {partial_derivative}K{sub +}, and at the inside, {partial_derivative}K{sub -}, of the boundary of the cloaked object K in the case where the permittivity and the permeability are bounded below and above in K. Namely, that the tangential components of the electric and the magnetic fields have to vanish at {partial_derivative}K{sub +}-which is always true-and that the normal components of the curl of the electric and the magnetic fields have to vanish at {partial_derivative}K{sub -}. These results are proven requiring that energy be conserved. In the case of one spherical cloak with a spherically stratified K and a radial current at {partial_derivative}K we verify by an explicit calculation that our cloaking boundary conditions are satisfied and that cloaking of active devices holds, even if the current is at the boundary of the cloaked object. As we prove our results for media that are obtained by transformation from general anisotropic media, our results apply to the cloaking of objects with passive and active devices contained in general anisotropic media, in particular to objects with passive and active devices contained inside general crystals. Our results suggest a method to enhance cloaking in the approximate transformation media that are used in practice. Namely, to coat the boundary of the cloaked object (the inner boundary of the cloak) with a material that imposes the

  18. On directionality of phrase structure building.

    Science.gov (United States)

    Chesi, Cristiano

    2015-02-01

    Minimalism in grammatical theorizing (Chomsky in The minimalist program. MIT Press, Cambridge, 1995) led to simpler linguistic devices and a better focalization of the core properties of the structure building engine: a lexicon and a free (recursive) phrase formation operation, dubbed Merge, are the basic components that serve in building syntactic structures. Here I suggest that by looking at the elementary restrictions that apply to Merge (i.e., selection and licensing of functional features), we could conclude that a re-orientation of the syntactic derivation (from bottom-up/right-left to top-down/left-right) is necessary to make the theory simpler, especially for long-distance (filler-gap) dependencies, and is also empirically more adequate. If the structure building operations would assemble lexical items in the order they are pronounced (Phillips in Order and structure. PhD thesis, MIT, 1996; Chesi in Phases and cartography in linguistic computation: Toward a cognitively motivated computational model of linguistic competence. PhD thesis, Università di Siena, 2004; Chesi in Competence and computation: Toward a processing friendly minimalist grammar. Unipress, Padova, 2012), on-line performance data could better fit the grammatical model, without resorting to external "performance factors." The phase-based, top-down (and, as a consequence, left-right) Minimalist Grammar here discussed goes in this direction, ultimately showing how strong Islands (Huang in Logical relations in Chinese and the theory of grammar. PhD thesis, MIT, 1982) and intervention effects (Gordon et al. in J Exp Psychol Learn Mem Cogn 27:1411-1423, 2001, Gordon et al. in J Mem Lang 51:97-114, 2004) could be better explained in structural terms assuming this unconventional derivational direction.

  19. 隐身材料%Cloaking materials

    Institute of Scientific and Technical Information of China (English)

    赖耘; 杭志宏; 黄学勤; 陈子亭

    2012-01-01

    由于超构材料(metamaterials)的发现,隐身(cloaking)科学近年来取得了长足的发展.与军事上的隐形(stealth)所不同的是,隐身指的是将电磁波的散射在各个方向上都完全消除,从而实现神话故事或科幻小说中那种真正的全方位、全角度的“消失”.隐身也因其重要的科学价值以及将对人类生活产生跨越式的改变而成为国际上的科研热点.除了隐身之外,科学家还证明了可以将物体变成任意的幻像,从而在光学上实现了孙悟空的“七十二变”,这被称为幻像光学(illusion optics).未来,隐身和幻像光学的发展有望将人类的极限想象变为现实.文章介绍了作者在隐身和幻像领域里的一些工作.%There has been extensive development in the study of cloaking technology since the discovery of metamaterials. Different from "stealth" technology used for military purposes, cloaking refers to a total annihilation of the scattering of electromagnetic waves in all directions, and thus achieving invisibility as depicted in mythology and sci-fiction. Because of its scientific importance and the possible dramatic impact on technology, cloaking has become a hot research topic. Moreover, illusion optics has also been demon- strated by means of which scientists can make an object "look like" anything else. The development of cloaking and illusion optics could turn human imagination to reality in the future. Some of our works in cloaking and illusion optics are reviewed here.

  20. Spontaneous emission and the operation of invisibility cloaks

    Science.gov (United States)

    Morshed Behbahani, Mina; Amooghorban, Ehsan; Mahdifar, Ali

    2016-07-01

    As a probe to explore the ability of invisibility cloaks to conceal objects in the quantum mechanics domain, we study the spontaneous emission rate of an excited two-level atom in the vicinity of an ideal invisibility cloaking. On this base, first, a canonical quantization scheme is presented for the electromagnetic field interacting with atomic systems in an anisotropic, inhomogeneous, and absorbing magnetodielectric medium which can suitably be used for studying the influence of arbitrary invisibility cloak on the atomic radiative properties. The time dependence of the atomic subsystem is obtained in the Schrodinger picture. By introducing a modified set of the spherical wave-vector functions, the Green tensor of the system is calculated via exact and discrete methods. In this formalism, the decay rate and as well the emission pattern of the aforementioned atom are computed analytically for both weak and strong coupling interaction, and then numerically calculations are done to demonstrate the performances of cloaking in the quantum mechanics domain. Special attention is paid to different possible orientations and locations of the atomic system near the spherical invisibility cloaking. Results in the presence and the absence of the invisibility cloak are compared. We find that the cloak works very well far from its resonance frequency to conceal a macroscopic object, whereas at near the resonance frequency the object is more visible than the situation where the object is not covered by the cloak.

  1. Impedance-Matched Reduced Acoustic Cloaking with Realizable Mass and Its Layered Design

    Institute of Scientific and Technical Information of China (English)

    CHEN Huan-Yang; YANG Tao; LUO Xu-Dong; MA Hong-Ru

    2008-01-01

    We present an impedance-matched reduced version of acoustic cloaking whose mass is in a reasonable range. A layered cloak design with isotropic material is also proposed for the reduced cloak. Numerical calculations from the transfer matrix methods show that the present layered cloak can reduce the scattering of an air cylinder substantially.

  2. Omnidirectional surface wave cloak using an isotropic homogeneous dielectric coating

    Science.gov (United States)

    Mitchell-Thomas, R. C.; Quevedo-Teruel, O.; Sambles, J. R.; Hibbins, A. P.

    2016-08-01

    The field of transformation optics owes a lot of its fame to the concept of cloaking. While some experimental progress has been made towards free-space cloaking in three dimensions, the material properties required are inherently extremely difficult to achieve. The approximations that then have to be made to allow fabrication produce unsatisfactory device performance. In contrast, when surface wave systems are the focus, it has been shown that a route distinct from those used to design free-space cloaks can be taken. This results in very simple solutions that take advantage of the ability to incorporate surface curvature. Here, we provide a demonstration in the microwave regime of cloaking a bump in a surface. The distortion of the shape of the surface wave fronts due to the curvature is corrected with a suitable refractive index profile. The surface wave cloak is fabricated from a metallic backed homogeneous dielectric waveguide of varying thickness, and exhibits omnidirectional operation.

  3. Hiding a Realistic Object Using a Broadband Terahertz Invisibility Cloak

    CERN Document Server

    Zhou, Fan; Cao, Wei; Stuart, Colin T; Gu, Jianqiang; Zhang, Weili; Sun, Cheng

    2011-01-01

    The invisibility cloak has been a long-standing dream for many researchers over the decades. The introduction of transformational optics has revitalized this field by providing a general method to design material distributions to hide the subject from detection. By transforming space and light propagation, a three-dimensional (3D) object is perceived as having a reduced number of dimensions, in the form of points, lines, and thin sheets, making it "undetectable" judging from the scattered field. Although a variety of cloaking devices have been reported at microwave and optical frequencies, the spectroscopically important Terahertz (THz) domain remains unexplored. Moreover, due to the difficulties in fabricating cloaking devices that are optically large in all three dimensions, hiding realistic 3D objects has yet to be demonstrated. Here, we report the first experimental demonstration of a 3D THz cloaking device fabricated using a scalable Projection Microstereolithography process. The cloak operates at a broa...

  4. Robustness Assessment of Building Structures under Explosion

    Directory of Open Access Journals (Sweden)

    Mark Waggoner

    2012-12-01

    Full Text Available Over the past decade, much research has focused on the behaviour of structures following the failure of a key structural component. Particular attention has been given to sudden column loss, though questions remain as to whether this event-independent scenario is relevant to actual extreme events such as explosion. Few studies have been conducted to assess the performance of floor slabs above a failed column, and the computational tools used have not been validated against experimental results. The research program presented in this paper investigates the adequacy of sudden column loss as an idealisation of local damage caused by realistic explosion events, and extends prior work by combining the development of accurate computational models with large-scale testing of a typical floor system in a prototypical steel-framed structure. The floor system consists of corrugated decking topped by a lightly reinforced concrete slab that is connected to the floor beams through shear studs. The design is consistent with typical building practices in the US. The first test has been completed, and subsequent tests are currently being planned. This paper addresses the importance of robustness design for localized damage and includes a detailed description regarding how the research program advances the current state of knowledge for assessing robustness of compositely constructed steel-framed buildings.

  5. Experimental demonstration of an ultra-thin three-dimensional thermal cloak

    CERN Document Server

    Xu, Hongyi; Gao, Fei; Sun, Handong; Zhang, Baile

    2013-01-01

    We report the first experimental realization of a three-dimensional thermal cloak shielding an air bubble in a bulk metal without disturbing external thermal flux. The cloak is made of a thin layer of homogeneous and isotropic material with simple mechanical manufacturing. The thickness of cloak is 200 um while the cloaked air bubble has a diameter of 1 cm, achieving the ratio between dimensions of the cloak and the cloaked object 2 orders smaller than previous thermal cloaks which were mainly realized at a two-dimensional plane. This work can find applications in novel thermal devices in the three-dimensional physical space.

  6. MODERN BUILDING STRUCTURES USED FOR MILITARY PURPOSES

    Directory of Open Access Journals (Sweden)

    Mariana Domnica STANCIU

    2014-04-01

    Full Text Available This paper investigates the technical aspects of the spherical spatial structures, focusing on the tensegrity building systems used for military purpose. The spherical spatial structures have been studied and used since antiquity. Pythagoras, Plato and Euclid were conducted extensive research on the concept of such type of structures. Regular pentagon has properties related to the value of the golden section, intuitively used by great architects and engineers since ancient times. In the Middle Ages, Leonardo Da Vinci created spatial objects using proportions based on the golden number, and later R. B. Fuller made the famous geodesic domes. The structures proposed by the authors are based on concepts related to the "golden section", on studies made on the regular pentagon, on the spatial volumes able to be inscribed in spheres and on the tensegrity systems. The proposed structures present some advantages related to the ease of mounting, to the volume covered, to the resistance to the environmental factors (snow, wind, earthquake, and so on. The paper presents the conclusions of the investigations on the components of the spatial structures and on the outcomes of their use.

  7. Asymmetric Cloaking Theory Based on Finsler Geometry ~ How to design Harry Potter's invisibility cloak with a scientific method ~

    CERN Document Server

    Amemiya, Tomohiro; Taki, Masato

    2012-01-01

    Is it possible to actually make Harry's invisibility cloaks? The most promising approach for realizing such magical cloaking in our real world would be to use transformation optics, where an empty space with a distorted geometry is imitated with a non-distorted space but filled with transformation medium having appropriate permittivity and permeability. An important requirement for practical invisibility cloaks is nonreciprocity; that is, a person in the cloak should not be seen from the outside but should be able to see the outside. This invisibility cloak, or a nonreciprocal shield, cannot be created as far as we stay in conventional transformation optics. Conventional transformation optics is based on Riemann geometry with a metric tensor independent of direction, and therefore cannot be used to design the nonreciprocal shield. To overcome this problem, we propose an improved theory of transformation optics that is based on Finsler geometry, an extended version of Riemann geometry. Our theory shows that no...

  8. The effect of electrostatic shielding using invisibility cloak

    Directory of Open Access Journals (Sweden)

    Ruo-Yang Zhang

    2011-12-01

    Full Text Available The effect of electrostatic shielding for a spherical invisibility cloak with arbitrary charges inside is investigated. Our result reveals that the charge inside the cloak is a crucial factor to determine the detection. When charged bodies are placed inside the cloak with an arbitrary distribution, the electric fields outside are purely determined by the total charges just as the fields of a point charge at the center of the cloak. As the total charges reduce to zero, the bodies can not be detected. On the other hand, if the total charges are nonzero, the electrostatic potential inside an ideal cloak tends to infinity. For unideal cloaks, this embarrassment is overcome, while they still have good behaviors of shielding. In addition, the potential across the inner surface of an ideal cloak is discontinuous due to the infinite polarization of the dielectric, however it can be alternatively interpreted as the dual Meissner effect of a dual superconductive layer with a surface magnetic current.

  9. Structural acceptance criteria Remote Handling Building Tritium Extraction Facility

    Energy Technology Data Exchange (ETDEWEB)

    Mertz, G.

    1999-12-16

    This structural acceptance criteria contains the requirements for the structural analysis and design of the Remote Handling Building (RHB) in the Tritium Extraction Facility (TEF). The purpose of this acceptance criteria is to identify the specific criteria and methods that will ensure a structurally robust building that will safely perform its intended function and comply with the applicable Department of Energy (DOE) structural requirements.

  10. Magnetic sensor for building structural vibrations.

    Science.gov (United States)

    García, Alfonso; Morón, Carlos; Tremps, Enrique

    2014-02-05

    This paper shows a new displacement-to-frequency transducer based on the variation of a coil inductance when a magnetic core is partially or completely inserted inside. This transducer is based on a Colpitts oscillator due its low manufacturing price, behavior and immunity to noise. A tank circuit with a configuration in parallel was used because it can be employed at lower frequencies and it enables it to make a direct analysis. The sensor has a dynamic range equal to the length of the coil. The cores can exchange sensors (coils with its ferromagnetic core) using the same electronic measuring system. In this way, with only an electronic circuit, the core sensor determines the measurement range. The obtained resolution is higher than 1/100,000, and the sensor also allows the measurement and knowing in real time the effect of vibration, thermal expansion, referred overload movements, etc.., that can occur in the structural elements of a building.

  11. Design of diamond-shaped transient thermal cloaks with homogeneous isotropic materials

    Science.gov (United States)

    Li, Ting-Hua; Zhu, Dong-Lai; Mao, Fu-Chun; Huang, Ming; Yang, Jing-Jing; Li, Shou-Bo

    2016-10-01

    Transformation thermodynamics as a major extension of transformation optics has recently received considerable attention. In this paper, we present two-dimensional (2D) and three-dimensional (3D) diamond-shaped transient thermal cloaks with non-singular homogeneous material parameters. The absence of singularity in the parameters results from the fact that the linear coordinate transformation is performed by expanding a line segment rather than a point into a region, while the mechanism behind the homogeneity is the homogeneous stretching and compression along orthogonal directions during the transformation. Although the derived parameters remain anisotropic, we further show that this can be circumvented by considering a layered structure composed of only four types of isotropic materials based on the effective medium theory. Numerical simulation results confirm the good performance of the proposed cloaks.

  12. Level Set-Based Topology Optimization for the Design of an Electromagnetic Cloak With Ferrite Material

    DEFF Research Database (Denmark)

    Otomori, Masaki; Yamada, Takayuki; Andkjær, Jacob Anders;

    2013-01-01

    This paper presents a structural optimization method for the design of an electromagnetic cloak made of ferrite material. Ferrite materials exhibit a frequency-dependent degree of permeability, due to a magnetic resonance phenomenon that can be altered by changing the magnitude of an externally...... applied dc magnetic field. Thus, such ferrite cloaks have the potential to provide novel functions, such as on-off operation in response to on-off application of an external magnetic field. The optimization problems are formulated to minimize the norm of the scattering field from a cylindrical obstacle....... A level set-based topology optimization method incorporating a fictitious interface energy is used to find optimized configurations of the ferrite material. The numerical results demonstrate that the optimization successfully found an appropriate ferrite configuration that functions as an electromagnetic...

  13. Plasma metamaterials as cloaking and nonlinear media

    Science.gov (United States)

    Sakai, O.; Yamaguchi, S.; Bambina, A.; Iwai, A.; Nakamura, Y.; Tamayama, Y.; Miyagi, S.

    2017-01-01

    Plasma metamaterials, composites of low-temperature plasmas and periodic functional microstructures, work as cloaking and nonlinear media. Due to functions of the microstructures like negative permeability, electromagnetic waves in and around plasma metamaterials propagate in a quite different manner from the case with the conventional space in which relative permeability is positive and unity. Using plasmas and plasma metamaterials, we achieve various controls of microwave propagating paths such as unidirectionality and cloaking in the two- or 3D spaces. For instance, a concentric plasma layer makes wave propagation unidirectional, and waves propagate in different routes when they start inside or outside the concentric layer. Furthermore, due to spatial permittivity gradient and anisotropic refractive index, electromagnetic waves detour in plasma metamaterial layers. Another significant point that plasma metamaterials can realize is nonlinearity. When we study high-power electromagnetic waves propagating in them, we observe several properties describable in terms of nonlinear dynamics and nonlinear photonics. Microwaves beyond threshold energy trigger bifurcations in plasma permittivity, and the second harmonic wave detected simultaneously is generated with strong emission levels. Such electromagnetic wave propagation is achieved with advantages over other materials, since plasmas and metallic microstructures work in harmony and in synergy.

  14. Acoustic cloaking and mirages with flying carpets

    CERN Document Server

    Diatta, Andre; Guenneau, Sebastien; Enoch, Stefan

    2009-01-01

    Carpets under consideration here, in the context of pressure acoustic waves propagating in a compressible fluid, do not touch the ground: they levitate in mid-air (or float in mid-water), which leads to approximate cloaking for an object hidden underneath, or touching either sides of a square cylinder on, or over, the ground. The tentlike carpets attached to the sides of a square cylinder illustrate how the notion of a carpet on a wall naturally generalizes to sides of other small compact objects. We then extend the concept of flying carpets to circular cylinders. However, instead of reducing its scattering cross-section like in acoustic cloaks, we rather mimic that of another obstacle, say a square rigid cylinder. For instance, show that one can hide any type of defects under such circular carpets, and yet they still scatter waves just like a smaller cylinder on its own. Interestingly, all these carpets are described by non-singular acoustic parameters. To exemplify this important aspect, we propose a multi-...

  15. Open active cloaking and illusion devices for the Laplace equation

    Science.gov (United States)

    Ma, Qian; Yang, Fan; Jin, Tian Yu; Lei Mei, Zhong; Cui, Tie Jun

    2016-04-01

    We propose open active cloaking and illusion devices for the Laplace equation. Compared with the closed configurations of active cloaking and illusion devices, we focus on improving the distribution schemes for the controlled sources, which do not have to surround the protected object strictly. Instead, the controlled sources can be placed in several small discrete clusters, and produce the desired voltages along the controlled boundary, to actively hide or disguise the protected object. Numerical simulations are performed with satisfactory results, which are further validated by experimental measurements. The open cloaking and illusion devices have many advantages over the closed configurations in various potential applications.

  16. Broadening the Cloaking Bandwidth with Non-Foster Metasurfaces

    Science.gov (United States)

    Chen, Pai-Yen; Argyropoulos, Christos; Alù, Andrea

    2013-12-01

    We introduce the concept and practical design of broadband, ultrathin cloaks based on non-Foster, negatively capacitive metasurfaces. By using properly tailored, active frequency-selective screens conformal to an object, within the realm of a practical realization, we show that it is possible to drastically reduce the scattering over a wide frequency range in the microwave regime, orders of magnitude broader than any available passive cloaking technology. The proposed active cloak may impact not only invisibility and camouflaging, but also practical antenna and sensing applications.

  17. Building Points - MO 2012 Stoddard Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Missouri Structure Points are structure points generated from a two pass look over the 2007 State 2ft imagery. Unlike the structure footprints, the building point...

  18. Building Points - MO 2012 Dunklin Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Missouri Structure Points are structure points generated from a two pass look over the 2007 State 2ft imagery. Unlike the structure footprints, the building point...

  19. Building Points - MO 2012 Scott Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Missouri Structure Points are structure points generated from a two pass look over the 2007 State 2ft imagery. Unlike the structure footprints, the building point...

  20. Building Points - MO 2012 Pemiscot Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Missouri Structure Points are structure points generated from a two pass look over the 2007 State 2ft imagery. Unlike the structure footprints, the building point...

  1. Building Points - MO 2012 New Madrid Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Missouri Structure Points are structure points generated from a two pass look over the 2007 State 2ft imagery. Unlike the structure footprints, the building point...

  2. Building Points - MO 2012 Mississippi Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Missouri Structure Points are structure points generated from a two pass look over the 2007 State 2ft imagery. Unlike the structure footprints, the building point...

  3. Active cloaking for clusters of pins in thin plates

    CERN Document Server

    O'Neill, Jane; Haslinger, Stewart; Movchan, Natasha; Craster, Richard

    2016-01-01

    This paper considers active cloaking of a square array of evenly spaced pins in a Kirchhoff plate in the presence of flexural waves. Active sources are distributed exterior to the cluster and are represented by the non-singular Green's function for the biharmonic operator. The complex amplitudes of the active sources, which cancel out selected multipole orders of the scattered field, are found by solving an algebraic system of equations. For frequencies in the zero-frequency stop band, we find that a small number of active sources located on a grid is sufficient for cloaking. For higher frequencies, we achieve efficient cloaking with the active sources positioned on a circle surrounding the cluster. We demonstrate the cloaking efficiency with several numerical illustrations, considering key frequencies from band diagrams and dispersion surfaces for a Kirchhoff plate pinned in a doubly periodic fashion.

  4. Achieving acoustic cloak by using compressible background flow

    Science.gov (United States)

    Zhang, Ruo-Yang; Zhao, Qing; Ge, Mo-Lin

    2016-08-01

    We propose a scheme of acoustic spherical cloaking by means of background irrotational flow in compressible fluid. The background flow forms a virtual curved spacetime and directs the sound waves to bypass the cloaked objects. To satisfy the laws of real fluid, we show that spatially distributed mass source and momentum source are necessary to supply. The propagation of sound waves in this system is studied via both geometric acoustics approximation and full wave approach. The analytic solution of sound fields is obtained for plane wave incidence. The results reveal the effect of phase retardation (or lead) in comparison with the ordinary transformation-acoustic cloak. In addition, the ability of cloaking is also evaluated for unideal background flows by analyzing the scattering cross section. Project supported by the National Natural Science Foundation of China (Grant Nos. 11475088 and 11275024) and the Fund from the Ministry of Science and Technology of China (Grant No. 2013YQ030595-3).

  5. Achieving acoustic cloak by using compressible background flow

    CERN Document Server

    Zhang, Ruo-Yang; Ge, Mo-Lin

    2016-01-01

    We propose a scheme of acoustic spherical cloaking by means of background irrotational flow in compressible fluid. The background flow forms a virtual curved spacetime and guides the sound waves bypass the cloaked objects. To satisfy the laws of real fluid, we show that spatially distributed mass source and momentum source are necessary to supply. The propagation of sound waves in this system is studied via both geometric acoustics approximation and full wave approach. The analytic solution of sound fields is obtained for plane wave incidence. The results reveal the effect of phase retardation (or lead) in comparison with the ordinary transformation-acoustic cloak. In addition, the ability of cloaking is also evaluated for unideal background flows by analyzing the scattering cross section.

  6. Utilization of structural steel in buildings.

    Science.gov (United States)

    Moynihan, Muiris C; Allwood, Julian M

    2014-08-01

    Over one-quarter of steel produced annually is used in the construction of buildings. Making this steel causes carbon dioxide emissions, which climate change experts recommend be reduced by half in the next 37 years. One option to achieve this is to design and build more efficiently, still delivering the same service from buildings but using less steel to do so. To estimate how much steel could be saved from this option, 23 steel-framed building designs are studied, sourced from leading UK engineering firms. The utilization of each beam is found and buildings are analysed to find patterns. The results for over 10 000 beams show that average utilization is below 50% of their capacity. The primary reason for this low value is 'rationalization'-providing extra material to reduce labour costs. By designing for minimum material rather than minimum cost, steel use in buildings could be drastically reduced, leading to an equivalent reduction in 'embodied' carbon emissions.

  7. Experimental demonstration of illusion optics with ``external cloaking'' effects

    Science.gov (United States)

    Li, Chao; Liu, Xiao; Liu, Guochang; Li, Fang; Fang, Guangyou

    2011-08-01

    A metamaterial "illusion optics" with "complementary medium" and "restoring medium" is designed by using inductor-capacitor (L-C) network medium. The unprecedented effects of "external cloaking" and "transforming one object to appear as another" are demonstrated experimentally. We also demonstrate that the non-resonant nature of the L-C network decreases the sensitivity of the "external cloaking" effect to the variation of the frequency and results in an acceptable bandwidth of the whole device.

  8. Time-of-flight imaging of invisibility cloaks

    CERN Document Server

    Halimeh, Jad C

    2011-01-01

    As invisibility cloaking has recently become experimental reality, it is interesting to explore ways to reveal remaining imperfections. In essence, the idea of most invisibility cloaks is to recover the optical path lengths without an object (to be made invisible) by a suitable arrangement around that object. Optical path length is proportional to the time of flight of a light ray or to the optical phase accumulated by a light wave. Thus, time-of-flight images provide a direct and intuitive tool for probing imperfections. Indeed, recent phase-sensitive experiments on the carpet cloak have already made early steps in this direction. In the macroscopic world, time-of-flight images could be measured directly by light detection and ranging (LIDAR). Here, we show calculated time-of-flight images of the conformal Gaussian carpet cloak, the conformal grating cloak, the cylindrical free-space cloak, and of the invisible sphere. All results are obtained by using a ray-velocity equation of motion derived from Fermat's ...

  9. Broadband solid cloak for underwater acoustics

    CERN Document Server

    Chen, Yi; Liu, Xiaoning; Bi, Yafeng; Sun, Zhaoyong; Xiang, Ping; Yang, Jun; Hu, Gengkai

    2016-01-01

    Shielding an object to be undetectable is an important issue for engineering applications. Cloaking is the ultimate shielding example, routing waves around an object without mutual interaction, demonstrated as possible in principle by transformation and metamaterial techniques. Example applications have been successfully designed and validated for electromagnetic wave, thin plate flexural wave, thermal flux, and airborne sound. However, for underwater acoustics, the commonly used scheme based on meta-fluids with anisotropic density for airborne sound is unworkable since an acoustic rigid material is required with mass density three orders of magnitude higher than water. Material with such high density is impossible using even the heaviest metal, and may suffer from a narrow working frequency band even if realized with locally resonant techniques. An alternative solution was recently suggested based on solid pentamode material, which can be impedance matched with water and has anisotropic modulus. Here, we rep...

  10. a Simplified Parameter Design Method for Transformation Optics-Based Metamaterial Innovative Cloak

    Science.gov (United States)

    Li, Ting-Hua; Huang, Ming; Yang, Jing-Jing; Lu, Jin; Cao, Hui-Lu

    2013-10-01

    Transformation optics-based innovative cloak which combines the virtues of both internal and external cloaks to enable arbitrary multi-objects hidden with visions and movements was first proposed by Huang et al. [Appl. Phys. Lett.101, 151901 (2012)]. But it is rather difficult to implement in practice, for the required material parameters vary with radius and even have singular values. To accelerate its practical realization but still keep good performance of invisibility, a simplified innovative cloak with only spatially varying axial parameter is developed via choosing appropriate transformation function. The advantage of such a cloak is that both radial and azimuthal parameters are constants, and all three components are nonsingular and finite. Full-wave simulation confirms the perfect cloaking effect of the cloak. Besides, the influences of metamaterials loss and parameter deviation on the performance of cloak are also investigated. This work provides a simple and feasible solution to push metamaterial-assisted innovative cloak more closely to the practice.

  11. Object-dependent cloaking in the first-order Born approximation

    NARCIS (Netherlands)

    Setälä, Tero; Hakkarainen, Timo; Friberg, Ari T.; Hoenders, Bernhard J.; Setälä, Tero

    2010-01-01

    We consider the cloaking of a slab object in scalar wave theory within the first-order Born approximation. We show that in the forward direction cloaking is achieved for any transversally invariant, positively refracting, and absorbing object by using a lossy, negative-index metamaterial cloak. Cloa

  12. Wind-resistant studies on tall buildings and structures

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    This paper introduces some aspects of wind-resistant studies of our research team on tall buildings and structures. Wind tunnel tests were carried out on 27 typical tall building models by using wind pressure scanning and HFFB techniques. The characteristics of wind pressures and forces acting on these buildings were analyzed. Some results have been adopted in a Shanghai code for structural design of steel tall buildings. Interference effects on wind forces and wind pressures among two and three tall buildings were experimentally investigated with about 10000 testing conditions. Regression analyses of the interference factors under different parameter conditions were made and the main regression formulas are presented. Theoretical study on equivalent static wind loads of tall buildings and structures are then introduced. Especially,a new concept of "mode coupling factor" and a modified SRSS method for wind response and equivalent static wind load of complicated tall buildings and structures with consideration of multi mode contributions and their coupling effects are presented. Finally,practical applications of wind-resistant studies on tall building and structures,taking the Guangzhou New TV Tower as an example,are presented.

  13. Relations between constructive peculiarities and structural behavior in Venice buildings

    OpenAIRE

    Doglioni, F.

    2012-01-01

    Here we are synthetically describing some constructive peculiarities of Venice civil buildings, analyzing the relation with the features of their structural decay and behavior in the long run. We suppose Venetian buildings, especially those parts which are conceived to suit the lagoon environment, to have undergone an evolution made of some adjustments, which were based on the observation of damages in previous buildings. That is we suppose ancient builders to rely on their awareness of the b...

  14. Building Footprints - Montana Structures/Addresses Framework

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — The Montana Structures/Addresses Framework is a statewide spatial database of structure and address points in the State of Montana. The Montana Structures/Addresses...

  15. Design of cloaking metamaterials using spectral representation theory

    Science.gov (United States)

    Lai Leung, Lai; Fung, Tai Hang; Yu, Kin Wah

    2008-03-01

    Controlling the propagation of electromagnetic (EM) waves, for instance in cloaking problem, has become an important topic in nanophotonics. So far, following the cloaking model proposed by Pendry et al. [1], the experimental realization was only limited to the microwave region [2]. Since practical application lies in the visible range, we have extended the investigation to that region by utilizing nanocomposites with reference to the material parameters proposed by Pendry et al. and Shalaev et al. [3]. The calculations can be made much simpler by invoking the spectral representation theory [4]. The loss and dispersion effects, as well as the propagation of EM waves are assessed for the designed cloaking models in order to investigate the cloaking performance. Further analyses show that our models can accomplish the desired cloaking effect in the visible range. Moreover, the loss and dispersion effects are found to be small and acceptable.[1] J. B. Pendry, D. Schurig, and D. R. Smith, Science 312, 1780 (2006). [2] D. Schurig, J. J. Mock, B. J. Justice, S. A. Cummer, J. B. Pendry, A. F. Starr, D. R. Smith Science 314, 5801 (2006). [3] Wenshan Cai, Uday K. Chettiar, Alexander V. Kildishev and Vladimir M. Shalaev, Nature photonics 1 (2007). [4] L. Dong, Mikko Karttunen, K. W. Yu, Phys. Rev. E 72, 016613 (2005).

  16. Iterative model-building, structure refinement, and density modification with the PHENIX AutoBuild Wizard

    Energy Technology Data Exchange (ETDEWEB)

    Los Alamos National Laboratory, Mailstop M888, Los Alamos, NM 87545, USA; Lawrence Berkeley National Laboratory, One Cyclotron Road, Building 64R0121, Berkeley, CA 94720, USA; Department of Haematology, University of Cambridge, Cambridge CB2 0XY, England; Terwilliger, Thomas; Terwilliger, T.C.; Grosse-Kunstleve, Ralf Wilhelm; Afonine, P.V.; Moriarty, N.W.; Zwart, P.H.; Hung, L.-W.; Read, R.J.; Adams, P.D.

    2007-04-29

    The PHENIX AutoBuild Wizard is a highly automated tool for iterative model-building, structure refinement and density modification using RESOLVE or TEXTAL model-building, RESOLVE statistical density modification, and phenix.refine structure refinement. Recent advances in the AutoBuild Wizard and phenix.refine include automated detection and application of NCS from models as they are built, extensive model completion algorithms, and automated solvent molecule picking. Model completion algorithms in the AutoBuild Wizard include loop-building, crossovers between chains in different models of a structure, and side-chain optimization. The AutoBuild Wizard has been applied to a set of 48 structures at resolutions ranging from 1.1 {angstrom} to 3.2 {angstrom}, resulting in a mean R-factor of 0.24 and a mean free R factor of 0.29. The R-factor of the final model is dependent on the quality of the starting electron density, and relatively independent of resolution.

  17. Invisible anti-cloak with elliptic cross section using phase complement

    Institute of Scientific and Technical Information of China (English)

    Yang Yu-Qi; Zhang Min; Yue Jian-Xiang

    2011-01-01

    Based on the theory of phase complement, an anti-cloak with circular cross section can be made invisible to an object outside its domain. As the cloak with elliptic cross section is more effective to make objects invisible than that with circular cross section, a scaled coordinate system is proposed to design equivalent materials of invisible anti-cloak with elliptic cross section using phase complement. The cloaks with conventional dielectric and double negative parameters are both simulated with the geometrical transformations. The results show that the cloak with elliptic cross section through phase complement can effectively hide the outside objects.

  18. Tuning plasmonic cloaks with an external magnetic field

    CERN Document Server

    Kort-Kamp, W J M; Pinheiro, F A; Farina, C

    2013-01-01

    We propose a mechanism to actively tune the operation of plasmonic cloaks with an external magnetic field by investigating electromagnetic scattering by a dielectric cylinder coated with a magneto-optical shell. In the long wavelength limit we show that the presence of an external magnetic field may drastically reduce the scattering cross-section at all observation angles. We demonstrate that the application of external magnetic fields can modify the operation wavelength without the need of changing material and/or geometrical parameters. We also show that applied magnetic fields can reversibly switch on and off the cloak operation. These results, which could be achieved for existing magneto-optical materials, are shown to be robust to material losses, so that they may pave the way for developing actively tunable, versatile plasmonic cloaks.

  19. PS buildings : reinforced concrete structure for shielding "bridge" pillar

    CERN Document Server

    CERN PhotoLab

    1956-01-01

    The PS ring traverses the region between the experimental halls South and North (buildings Nos 150 and 151) under massive bridge-shaped concrete beams. This pillar stands at the S-W end of the structure.

  20. Push-Over Analysis for Concrete Structures of Tall Building

    Institute of Scientific and Technical Information of China (English)

    朱杰江; 张佩军; 吕西林; 容柏生

    2004-01-01

    In this paper, push-over analysis for tall concrete structures was made and a corresponding computer program was given.Several kinds of elements in the program were considered to meet the demand of tall buildings with complex structural type. These elements included beam-column element for beams and columns, single slice wall element and three vertical line element for walls, and tube-wall element for tubes. Computational example for verifying the models indicates that the result obtained by this method is identical with a well-known test result and the program can be used to search for the full process of structural reaction, even the softening stage of the structure. With this push-over analysis method, an actual tall building with complex structural type was analyzed, and the result has been put into practice of the structural design of the building.

  1. Detection of a diffusive cloak via second-order statistics

    CERN Document Server

    Koirala, Milan

    2016-01-01

    We propose a scheme to detect the diffusive cloak proposed by Schittny et al [Science 345, 427 (2014)]. We exploit the fact that diffusion of light is an approximation that disregards wave interference. The long-range contribution to intensity correlation is sensitive to locations of paths crossings and the interference inside the medium, allowing one to detect the size and position, including the depth, of the diffusive cloak. Our results also suggest that it is possible to separately manipulate the first- and the second-order statistics of wave propagation in turbid media.

  2. Thermal invisibility based on scattering cancellation and mantle cloaking

    KAUST Repository

    Farhat, M.

    2015-04-30

    We theoretically and numerically analyze thermal invisibility based on the concept of scattering cancellation and mantle cloaking. We show that a small object can be made completely invisible to heat diffusion waves, by tailoring the heat conductivity of the spherical shell enclosing the object. This means that the thermal scattering from the object is suppressed, and the heat flow outside the object and the cloak made of these spherical shells behaves as if the object is not present. Thermal invisibility may open new vistas in hiding hot spots in infrared thermography, military furtivity, and electronics heating reduction.

  3. Spontaneous emission and the operation of invisibility cloaks: Can the invisibility cloaks render objects invisible in quantum mechanic domain?

    CERN Document Server

    Behbahani, Mina Morshed; Mahdifar, Ali

    2016-01-01

    As a probe to explore the ability of invisibility cloaks to conceal objects in the quantum mechanics domain, we study the spontaneous emission rate of an excited two-level atom in the vicinity of an ideal invisibility cloaking. On this base, first, a canonical quantization scheme is presented for the electromagnetic field interacting with atomic systems in an anisotropic, inhomogeneous and absorbing magnetodielectric medium which can suitably be used for studying the influence of arbitrary invisibility cloak on the atomic radiative properties. The time dependence of the atomic subsystem is obtained in the Schrodinger picture. By introducing a modified set of the spherical wave vector functions, the Green tensor of the system is calculated via the continuous and discrete methods. In this formalism, the decay rate and as well the emission pattern of the aforementioned atom are computed analytically for both weak and strong coupling interaction, and then numerically calculations are done to demonstrate the perfo...

  4. Building structure-activity insights through patent mining.

    Science.gov (United States)

    Tu, Meihua; Pfefferkorn, Jeffrey A; Guzman-Perez, Angel; Filipski, Kevin J

    2012-11-01

    One gap in current patent-mining practice is the lack of tools to build SAR knowledge. Here, we report a novel technique that enabled us to derive useful SAR information from the exemplified structures of a series of patents. In our approach, exemplified chemical structures were extracted from patent documents. They were grouped into structural series based on similarity and binding mode, after which the R-group table was generated. By analyzing R-group usages over time, we were able to build insights into SAR of a structural series, even though the biological activities were not available.

  5. Structural Simulations and Conservation Analysis -Historic Building Information Model (HBIM

    Directory of Open Access Journals (Sweden)

    C. Dore

    2015-02-01

    Full Text Available In this paper the current findings to date of the Historic Building Information Model (HBIM of the Four Courts in Dublin are presented. The Historic Building Information Model (HBIM forms the basis for both structural and conservation analysis to measure the impact of war damage which still impacts on the building. The laser scan survey was carried out in the summer of 2014 of the internal and external structure. After registration and processing of the laser scan survey, the HBIM was created of the damaged section of the building and is presented as two separate workflows in this paper. The first is the model created from historic data, the second a procedural and segmented model developed from laser scan survey of the war damaged drum and dome. From both models structural damage and decay simulations will be developed for documentation and conservation analysis.

  6. Soil Structure Interaction between Two Adjacent Buildings under Earthquake Load

    Directory of Open Access Journals (Sweden)

    Mahmoud Yahyai

    2008-01-01

    Full Text Available In some cases, tall buildings are located in geotechnically unsuitable places, due to their high ratio of height to width; there is risk of uplift and other effects such as overturning and reduction structure serviceability during earthquake. This research is aimed to evaluate the effect of Soil-Structure Interaction (SSI on seismic behavior of two adjacent 32 story buildings such as time period, base shear and displacements. The interaction effects are investigated for variable distance between the two buildings. Three types of soil such as soft clay, sandy gravel and compacted sandy gravel are considered for this study. The result obtained that the interaction effect increases time period of both buildings base shear and lateral displacement of the structures increases.

  7. Structural response of steel high rise buildings to fire

    DEFF Research Database (Denmark)

    Gentili, Filippo; Giuliani, Luisa; Bontempi, Franco

    2013-01-01

    Due to the significant vertical elevation and complexity of the structural system, high rise buildings may suffer from the effects of fire more than other structures. For this reason, in addition to evacuation strategies and active fire protection, a careful consideration of structural response...... to fire is also very important. In this context, it is of interest to investigate the characteristics of the structural system that could possibly reduce local damages or mitigate the progression of failures in case of fire. In this paper, a steel high rise building is taken as case study and the response...... of the building is investigated up to the crisis of the structure with respect to a standard fire in a lower and in a higher storey: the comparison of the fire induced failures at the different height allows highlighting the role played in the resulting collapse mechanisms by the beam-column stiffness ratio...

  8. Folded Plate Structures as Building Envelopes

    DEFF Research Database (Denmark)

    Falk, Andreas; Buelow, Peter von; Kirkegaard, Poul Henning

    2012-01-01

    This paper treats applications of cross-laminated timber (CLT) in structural systems for folded façade solutions. Previous work on CLT-based systems for folded roofs has shown a widening range of structural possibilities to develop timber-based shells. Geometric and material properties play......, however, an important role also for the enclosure, and climate and conceptual design procedures have been utilised to include these issues in early design phases. A current architectural trend proposes increasing complexity of the façades and in this context the paper proposes the application of folded...

  9. Metamaterial-Based Cylinders Used for Invisible Cloak Realization

    Science.gov (United States)

    2011-08-01

    Branimir Ivsic Tin Komljenovic University of Zagreb Faculty of Electrical Engineering and Computing Unska 3 Zagreb, Croatia HR-10000...PROGRAM ELEMENT NUMBER 61102F 6. AUTHOR(S) Zvonimir Sipus Dario Bojanjac Branimir Ivsic Tim Komljenovic 5d. PROJECT NUMBER 5d. TASK...Used for Invisible Cloak Realization by Zvonimir Sipus Dario Bojanjac Branimir Ivsic Tin Komljenovic

  10. Structuring oil by protein building blocks

    NARCIS (Netherlands)

    Vries, de Auke

    2017-01-01

    Over the recent years, structuring of oil into ‘organogels’ or ‘oleogels’ has gained much attention amongst colloid-, material,- and food scientists. Potentially, these oleogels could be used as an alternative for saturated- and trans fats in food products. To develop oleogel

  11. Graphene based metamaterials for terahertz cloaking and subwavelength imaging

    Science.gov (United States)

    Forouzmand, Seyedali

    Graphene is a two-dimensional carbon crystal that became one of the most controversial topics of research in the last few years. The intense interest in graphene stems from recent demonstrations of their potentially revolutionary electromagnetic applications -- including negative refraction, subdiffraction imaging, and even invisibility -- which have suggested a wide range of new devices for communications, sensing, and biomedicine. In addition, it has been shown that graphene is amenable to unique patterning schemes such as cutting, bending, folding, and fusion that are predicted to lead to interesting properties. A recent proposed application of graphene is in engineering the scattering properties of objects, which may be leveraged in applications such as radar-cross-section management and stealth, where it may be required to make one object look like another object or render an object completely invisible. We present the analytical formulation for the analysis of electromagnetic interaction with a finite conducting wedge covered with a cylindrically shaped nanostructured graphene metasurface, resulting in the scattering cancellation of the dominant scattering mode for all the incident and all the observation angles. Following this idea, the cylindrical graphene metasurface is utilized for cloaking of several concentric finite conducting wedges. In addition, a wedge shaped metasurface is proposed as an alternative approach for cloaking of finite wedges. The resolution of the conventional imaging lenses is restricted by the natural diffraction limit. Artificially engineered metamaterials now offer the possibility of creating a superlens that overcomes this restriction. We demonstrate that a wire medium (WM) slab loaded with graphene sheets enables the enhancement of the near field for subwavelength imaging at terahertz (THz) frequencies. The analysis is based on the nonlocal homogenization model for WM with the additional boundary condition in the connection of

  12. Folded Plate Structures as Building Envelopes

    DEFF Research Database (Denmark)

    Falk, Andreas; Buelow, Peter von; Kirkegaard, Poul Henning

    2012-01-01

    , however, an important role also for the enclosure, and climate and conceptual design procedures have been utilised to include these issues in early design phases. A current architectural trend proposes increasing complexity of the façades and in this context the paper proposes the application of folded...... CLT-based systems, which are studied and analysed by using a combination of digital tools for structural and environmental design and analysis. The results show gainful, rational properties of folded systems and beneficial effects from an integration of architectural and environmental performance...... criteria in the design of CLT-based façades....

  13. General problems of technical diagnosis of non-metal building structures in explotable buildings and erections

    Directory of Open Access Journals (Sweden)

    V.G. Shtengel

    2010-11-01

    Full Text Available For successful realization of survey it is necessary to solve varioius technical and organizational problems. Each of them influence on completeness and reliability of information and thus, objectivity of conclusions about real state of structures and building as a whole, and also forecasting of its further exploitation. In the article the classification and brief analysis of these problems is given.

  14. Photorealistic ray tracing of free-space invisibility cloaks made of uniaxial dielectrics

    CERN Document Server

    Halimeh, Jad C

    2012-01-01

    The design rules of transformation optics generally lead to spatially inhomogeneous and anisotropic impedance-matched magneto-dielectric material distributions for, e.g., free-space invisibility cloaks. Recently, simplified anisotropic non-magnetic free-space cloaks made of a locally uniaxial dielectric material (calcite) have been realized experimentally. In a two-dimensional setting and for in-plane polarized light propagating in this plane, the cloaking performance can still be perfect for light rays. However, for general views in three dimensions, various imperfections are expected. In this paper, we study two different purely dielectric uniaxial cylindrical free-space cloaks. For one, the optic axis is along the radial direction, for the other one it is along the azimuthal direction. The azimuthal uniaxial cloak has not been suggested previously to the best of our knowledge. We visualize the cloaking performance of both by calculating photorealistic images rendered by ray tracing. Following and complemen...

  15. A 3D tunable and multi-frequency graphene plasmonic cloak

    KAUST Repository

    Farhat, Mohamed

    2013-01-01

    We demonstrate the possibility of cloaking three-dimensional objects at multi-frequencies in the far-infrared part of the spectrum. The proposed cloaking mechanism exploits graphene layers wrapped around the object to be concealed. Graphene layers are doped via a variable external voltage difference permitting continuous tuning of the cloaking frequencies. Particularly, two configurations are investigated: (i) Only one graphene layer is used to suppress the scattering from a dielectric sphere. (ii) Several of these layers biased at different gate voltages are used to achieve a multi-frequency cloak. These frequencies can be set independently. The proposed cloak\\'s functionality is verified by near- and far-field computations. By considering geometry and material parameters that are realizable by practical experiments, we contribute to the development of graphene based plasmonic applications that may find use in disruptive photonic technologies. © 2013 Optical Society of America.

  16. Structural approach for building reconstruction from a single DSM.

    Science.gov (United States)

    Lafarge, Florent; Descombes, Xavier; Zerubia, Josiane; Pierrot-Deseilligny, Marc

    2010-01-01

    We present a new approach for building reconstruction from a single Digital Surface Model (DSM). It treats buildings as an assemblage of simple urban structures extracted from a library of 3D parametric blocks (like a LEGO set). First, the 2D-supports of the urban structures are extracted either interactively or automatically. Then, 3D-blocks are placed on the 2D-supports using a Gibbs model which controls both the block assemblage and the fitting to data. A Bayesian decision finds the optimal configuration of 3D-blocks using a Markov Chain Monte Carlo sampler associated with original proposition kernels. This method has been validated on multiple data set in a wide-resolution interval such as 0.7 m satellite and 0.1 m aerial DSMs, and provides 3D representations on complex buildings and dense urban areas with various levels of detail.

  17. FEM Updating of the Heritage Court Building Structure

    DEFF Research Database (Denmark)

    Ventura, C. E.; Brincker, Rune; Dascotte, E.

    2001-01-01

    . The starting model of the structure was developed from the information provided in the design documentation of the building. Different parameters of the model were then modified using an automated procedure to improve the correlation between measured and calculated modal parameters. Careful attention......This paper describes results of a model updating study conducted on a 15-storey reinforced concrete shear core building. The output-only modal identification results obtained from ambient vibration measurements of the building were used to update a finite element model of the structure...... was placed to the selection of the parameters to be modified by the updating software in order to ensure that the necessary changes to the model were realistic and physically realisable and meaningful. The paper highlights the model updating process and provides an assessment of the usefulness of using...

  18. Analysis of the structural design process of the adaptive reuse of building structures

    NARCIS (Netherlands)

    Pasterkamp, S.

    2014-01-01

    In the field of structural building engineering there is a market shift taking place as a result of the growing number of buildings that are listed as cultural heritage, secularization, the economic situation and the increasing office vacancy rate in Europe and the US. More and more structural engin

  19. Broadening the Bandwidth of Metamaterial Cloaks with Non-Foster Metasurfaces

    CERN Document Server

    Chen, Pai-Yen; Alu, Andrea

    2013-01-01

    We introduce the concept and practical design of broadband, ultrathin cloaks based on non-Foster, negatively capacitive metasurfaces. By using properly tailored, active frequency-selective screens conformal to an object, within the realm of practical realization, is shown to enable drastically reduced scattering over a wide frequency range in the microwave regime, orders of magnitude broader than any available passive cloaking technology. The proposed active cloak may impact not only invisibility and camouflaging, but also practical antenna and sensing applications.

  20. Exploring the proper experimental conditions in 2D thermal cloaking demonstration

    Science.gov (United States)

    Hu, Run; Zhou, Shuling; Yu, Xingjian; Luo, Xiaobing

    2016-10-01

    Although thermal cloak has been studied extensively, the specific discussions on the proper experimental conditions to successfully observe the thermal cloaking effect are lacking. In this study, we focus on exploring the proper experimental conditions for 2D thermal cloaking demonstration. A mathematical model is established and detailed discussions are presented based on the model. The proper experimental conditions are suggested and verified with finite element simulations.

  1. Structure Building Predicts Grades in College Psychology and Biology

    Science.gov (United States)

    Arnold, Kathleen M.; Daniel, David B.; Jensen, Jamie L.; McDaniel, Mark A.; Marsh, Elizabeth J.

    2016-01-01

    Knowing what skills underlie college success can allow students, teachers, and universities to identify and to help at-risk students. One skill that may underlie success across a variety of subject areas is structure building, the ability to create mental representations of narratives (Gernsbacher, Varner, & Faust, 1990). We tested if…

  2. Surface Wave Cloak from Graded Refractive Index Nanocomposites

    Science.gov (United States)

    La Spada, L.; McManus, T. M.; Dyke, A.; Haq, S.; Zhang, L.; Cheng, Q.; Hao, Y.

    2016-07-01

    Recently, a great deal of interest has been re-emerged on the possibility to manipulate surface waves, in particular, towards the THz and optical regime. Both concepts of Transformation Optics (TO) and metamaterials have been regarded as one of key enablers for such applications in applied electromagnetics. In this paper, we experimentally demonstrate for the first time a dielectric surface wave cloak from engineered gradient index materials to illustrate the possibility of using nanocomposites to control surface wave propagation through advanced additive manufacturing. The device is designed analytically and validated through numerical simulations and measurements, showing good agreement and performance as an effective surface wave cloak. The underlying design approach has much wider applications, which span from microwave to optics for the control of surface plasmon polaritons (SPPs) and radiation of nanoantennas.

  3. A simple construction for a cylindrical cloak via inverse homogenization

    CERN Document Server

    Anderson, Tom H; Lakhtakia, Akhlesh

    2011-01-01

    An effective cylindrical cloak may be conceptualized as an assembly of adjacent local neighbourhoods, each of which is made from a homogenized composite material (HCM). The HCM is required to be a certain uniaxial dielectric-magnetic material, characterized by positive-definite constitutive dyadics. It can arise from the homogenization of remarkably simple component materials, such as two isotropic dielectric-magnetic materials, randomly distributed as oriented spheroidal particles. By carefully controlling the spheroidal shape of the component particles, a high degree of HCM anisotropy may be achieved, which is necessary for the cloaking effect to be realized. The inverse Bruggeman formalism can provide estimates of the shape and constitutive parameters for the component materials, as well as their volume fractions.

  4. Acoustic carpet cloak based on an ultrathin metasurface

    Science.gov (United States)

    Esfahlani, Hussein; Karkar, Sami; Lissek, Herve; Mosig, Juan R.

    2016-07-01

    An acoustic metasurface carpet cloak based on membrane-capped cavities is proposed and investigated numerically. This design has been chosen for allowing ultrathin geometries, although adapted to airborne sound frequencies in the range of 1 kHz (λ ≈30 cm), surpassing the designs reported in the literature in terms of thinness. A formulation of generalized Snell's laws is first proposed, mapping the directions of the incident and reflected waves to the metasurface phase function. This relation is then applied to achieve a prescribed wavefront reflection direction, for a given incident direction, by controlling the acoustic impedance grading along the metasurface. The carpet cloak performance of the proposed acoustic metasurface is then assessed on a triangular bump obstacle, generally considered as a baseline configuration in the literature.

  5. Unraveling an Old Cloak: k-anonymity for Location Privacy

    OpenAIRE

    Shokri, Reza; Troncoso, Carmela; Diaz, Claudia; Freudiger, Julien; Hubaux, Jean-Pierre

    2010-01-01

    There is a rich collection of literature that aims at protecting the privacy of users querying location-based services. One of the most popular location privacy techniques consists in cloaking users' locations such that k users appear as potential senders of a query, thus achieving k-anonymity. This paper analyzes the effectiveness of k-anonymity approaches for protecting location privacy in the presence of various types of adversaries. The unraveling of the scheme unfolds the inconsistency b...

  6. Cooling of the Building Structure by Night-time Ventilation

    DEFF Research Database (Denmark)

    Artmann, Nikolai

    , architects and engineers are still hesitant to apply passive cooling techniques. The basic concept of night-time ventilation involves cooling the building structure overnight in order to provide a heat sink during the occupancy period. As this requires a sufficiently high temperature difference between...... a building energy simulation program (HELIOS), and the effect of different parameters such as building construction, heat gains, air change rates, heat transfer coefficients and climatic conditions on the number of overheating degree hours (operative room temperature >26 °C) was evaluated. Besides climatic...... air flow rates and the possibility of a cold air jet flowing along the ceiling, but the magnitude of these effects is hard to predict. Heat transfer during night-time ventilation in case of mixing and displacement ventilation has been investigated in a full scale test room. The performance of night...

  7. Performance Comparison between Structural Element of Building Systems in Malaysia

    Directory of Open Access Journals (Sweden)

    M. R. Abdul Kadir

    2005-01-01

    Full Text Available The Industrialized Building System (IBS was introduced in Malaysia in 1966, but it failed to establish itself on a continuous basis though there has been a sustained large market for residential projects even since. One of the reasons behind this shortcoming is the lack of scientific data on labor productivity that could convince policy maker. Hence, the objective of this study is to develop a standardized data collection methodology for measuring and comparing the conventional building system and IBS in term of labor productivity, crew size and cycle time. Labor productivity (man hours/m2 is defined as the man hours required to complete the structural element of one unit house. A total of 499 data points were obtained from seven residential projects constructed between January 2003 and April 2004. Analysis of Variance (ANOVA indicated that the labor productivity was significantly different between four structural building systems. The mean labor productivity for the conventional building system was 4.20 man hours/m2 followed by cast in-situ table form (2.70 man hours/m2, cast in-situ half tunnel form (1.88 man hours/m2 and pre-cast concrete system (1.33 man hours/m2. Further, the analysis of crew size indicated that the mean crew size of a conventional building system of 24 workers was significantly different from the IBS of 22 workers. However, the crew size within the IBS was found to be insignificant. The cycle time measured in days per house was found to be significantly different between structural building systems with the conventional building system of 4.9 days, cast in-situ table form of 3.9 days, cast in-situ half tunnel form of 2.9 days and pre-cast concrete system for 2.3 days. The labor productivity obtained from this study could be used as a preliminary guideline for a client or consultant to identify the most appropriate building system for executing a construction project and determining the labor requirement in the construction

  8. Salt Damage and Rising Damp Treatment in Building Structures

    Directory of Open Access Journals (Sweden)

    J. M. P. Q. Delgado

    2016-01-01

    Full Text Available Salt damage can affect the service life of numerous building structures, both historical and contemporary, in a significant way. In this review, various damage mechanisms to porous building materials induced by salt action are analyzed. The importance of pretreatment investigations is discussed as well; in combination with the knowledge of salt and moisture transport mechanisms they can give useful indications regarding treatment options. The methods of salt damage treatment are assessed then, including both passive techniques based on environmental control, reduction of water transport, or conversion to less soluble salts and active procedures resulting in the removal of salts from deterioration zones. It is concluded that cellulose can still be considered as the favorite material presently used in desalination poultices but hydrophilic mineral wool can serve as its prospective alternative in future applications. Another important cause of building pathologies is the rising damp and, in this phenomenon, it is particularly severe considering the presence of salts in water. The treatment of rising damp in historic building walls is a very complex procedure and at Laboratory of Building Physics (LFC-FEUP a wall base hygroregulated ventilation system was developed and patented.

  9. Structural evaluation of existing plutonium buildings and auxiliary structures at Rocky Flats Plant

    Energy Technology Data Exchange (ETDEWEB)

    1980-02-01

    Existing plutonium handling and storage buildings at the DOE Rocky Flats Plant were evaluated for their structural resistance to seismic, tornado, and extreme wind loadings and the impact of tornado-driven missiles. This report presents the summary results of the study for all the buildings included in the study and makes preliminary general recommendations for upgrading where needed. Detailed analyses and backup calculations performed for the several buildings are presented in separate reports.

  10. Multi functional roof structures of the energy efficient buildings

    Directory of Open Access Journals (Sweden)

    Krstić Aleksandra

    2006-01-01

    Full Text Available Modern architectural concepts, which are based on rational energy consumption of buildings and the use of solar energy as a renewable energy source, give the new and significant role to the roofs that become multifunctional structures. Various energy efficient roof structures and elements, beside the role of protection, provide thermal and electric energy supply, natural ventilation and cooling of a building, natural lighting of the indoor space sunbeam protection, water supply for technical use, thus according to the above mentioned functions, classification and analysis of such roof structures and elements are made in this paper. The search for new architectural values and optimization in total energy balance of a building or the likewise for the urban complex, gave to roofs the role of "climatic membranes". Contemporary roof forms and materials clearly exemplify their multifunctional features. There are numerous possibilities to achieve the new and attractive roof design which broadens to the whole construction. With such inducement, this paper principally analyze the configuration characteristics of the energy efficient roof structures and elements, as well as the visual effects that may be achieved by their application.

  11. Direct Georeferencing of Uav Data Based on Simple Building Structures

    Science.gov (United States)

    Tampubolon, W.; Reinhardt, W.

    2016-06-01

    Unmanned Aerial Vehicle (UAV) data acquisition is more flexible compared with the more complex traditional airborne data acquisition. This advantage puts UAV platforms in a position as an alternative acquisition method in many applications including Large Scale Topographical Mapping (LSTM). LSTM, i.e. larger or equal than 1:10.000 map scale, is one of a number of prominent priority tasks to be solved in an accelerated way especially in third world developing countries such as Indonesia. As one component of fundamental geospatial data sets, large scale topographical maps are mandatory in order to enable detailed spatial planning. However, the accuracy of the products derived from the UAV data are normally not sufficient for LSTM as it needs robust georeferencing, which requires additional costly efforts such as the incorporation of sophisticated GPS Inertial Navigation System (INS) or Inertial Measurement Unit (IMU) on the platform and/or Ground Control Point (GCP) data on the ground. To reduce the costs and the weight on the UAV alternative solutions have to be found. This paper outlines a direct georeferencing method of UAV data by providing image orientation parameters derived from simple building structures and presents results of an investigation on the achievable results in a LSTM application. In this case, the image orientation determination has been performed through sequential images without any input from INS/IMU equipment. The simple building structures play a significant role in such a way that geometrical characteristics have been considered. Some instances are the orthogonality of the building's wall/rooftop and the local knowledge of the building orientation in the field. In addition, we want to include the Structure from Motion (SfM) approach in order to reduce the number of required GCPs especially for the absolute orientation purpose. The SfM technique applied to the UAV data and simple building structures additionally presents an effective tool

  12. Metasurface Cloak Performance Near-by Multiple Line Sources and PEC Cylindrical Objects

    DEFF Research Database (Denmark)

    Arslanagic, Samel; Yatman, William H.; Pehrson, Signe

    2014-01-01

    The performance/robustness of metasurface cloaks to a complex field environment which may represent a realistic scenario of radiating sources is presently reported. Attention is devoted to the cloak operation near-by multiple line sources and multiple perfectly electrically conducting cylinders...

  13. The scattering of a cylindrical invisibility cloak: reduced parameters and optimization

    DEFF Research Database (Denmark)

    Peng, Liang; Ran, L.; Mortensen, Asger

    2011-01-01

    We investigate the scattering of 2D cylindrical invisibility cloaks with simplified constitutive parameters with the assistance of scattering coefficients. We show that the scattering of the cloaks originates not only from the boundary conditions but also from the spatial variation of the compone...

  14. Structural Analysis and Seismic Design for Cold Neutron Laboratory Building

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Sangik; Kim, Y. K.; Kim, H. R

    2007-05-15

    This report describes all the major results of the dynamic structural analysis and seismic design for the Cold Neutron Laboratory Building which is classified in seismic class II. The results are summarized of the ground response spectrum as seismic input loads, mechanical properties of subsoil, the buoyancy stability due to ground water, the maximum displacement of the main frame under the seismic load and the member design. This report will be used as a basic design report to maintenance its structural integrity in future.

  15. DIRECT GEOREFERENCING OF UAV DATA BASED ON SIMPLE BUILDING STRUCTURES

    Directory of Open Access Journals (Sweden)

    W. Tampubolon

    2016-06-01

    Full Text Available Unmanned Aerial Vehicle (UAV data acquisition is more flexible compared with the more complex traditional airborne data acquisition. This advantage puts UAV platforms in a position as an alternative acquisition method in many applications including Large Scale Topographical Mapping (LSTM. LSTM, i.e. larger or equal than 1:10.000 map scale, is one of a number of prominent priority tasks to be solved in an accelerated way especially in third world developing countries such as Indonesia. As one component of fundamental geospatial data sets, large scale topographical maps are mandatory in order to enable detailed spatial planning. However, the accuracy of the products derived from the UAV data are normally not sufficient for LSTM as it needs robust georeferencing, which requires additional costly efforts such as the incorporation of sophisticated GPS Inertial Navigation System (INS or Inertial Measurement Unit (IMU on the platform and/or Ground Control Point (GCP data on the ground. To reduce the costs and the weight on the UAV alternative solutions have to be found. This paper outlines a direct georeferencing method of UAV data by providing image orientation parameters derived from simple building structures and presents results of an investigation on the achievable results in a LSTM application. In this case, the image orientation determination has been performed through sequential images without any input from INS/IMU equipment. The simple building structures play a significant role in such a way that geometrical characteristics have been considered. Some instances are the orthogonality of the building’s wall/rooftop and the local knowledge of the building orientation in the field. In addition, we want to include the Structure from Motion (SfM approach in order to reduce the number of required GCPs especially for the absolute orientation purpose. The SfM technique applied to the UAV data and simple building structures additionally presents an

  16. Directional cloaking of flexural waves in a plate with a locally resonant metamaterial.

    Science.gov (United States)

    Colombi, Andrea; Roux, Philippe; Guenneau, Sebastien; Rupin, Matthieu

    2015-04-01

    This paper deals with the numerical design of a directional invisibility cloak for backward scattered elastic waves propagating in a thin plate (A0 Lamb waves). The directional cloak is based on a set of resonating beams that are attached perpendicular to the plate and are arranged at a sub-wavelength scale in ten concentric rings. The exotic effective properties of this locally resonant metamaterial ensure coexistence of bandgaps and directional cloaking for certain beam configurations over a large frequency band. The best directional cloaking was obtained when the resonators' length decreases from the central to the outermost ring. In this case, flexural waves experience a vanishing index of refraction when they cross the outer layers, leading to a frequency bandgap that protects the central part of the cloak. Numerical simulation shows that there is no back-scattering in these configurations. These results might have applications in the design of seismic-wave protection devices.

  17. Three-dimensional magnetic cloak working from DC to 250 kHz

    CERN Document Server

    Zhu, Jianfei; Liu, Yichao; Yin, Ge; Yuan, Jun; He, Sailing; Ma, Yungui

    2015-01-01

    Invisible cloaking is one of major outcomes of the metamaterial research, but the practical potential, in particular for high frequencies (e.g., microwave to visible light), is fatally challenged by the complex material properties they usually demand. On the other hand, it will be advantageous and also technologically instrumental to design cloaking devices for applications at low frequencies where electromagnetic components are favorably uncoupled. In this work, we vastly develop the bilayer approach to create a three-dimensional magnetic cloak able to work in both static and dynamic fields. Under the quasi-static approximation, we demonstrate a perfect magnetic cloaking device with a large frequency band from zero to 250 kHz. The practical potential of our device is experimentally verified by using a commercial metal detector, which may lead us to having a real cloaking application where the dynamic magnetic field can be manipulated in desired ways.

  18. Invisibility Cloaks Modeled by Anisotropic Metamaterials Based on Inductor-capacitor Networks

    CERN Document Server

    Liu, Xiao; Yao, Kan; Meng, Xiankun; Li, Fang

    2009-01-01

    Base on the transformation optics, a novel transmission-line (TL) approach to realize invisibility cloaking using planar anisotropic metamaterials (MTMs) is proposed. The two-dimensional cylindrical cloaks are modeled based on inductor-capacitor (L-C) MTMs networks. The three elements of the constitutive parameters are all allowed to be spatially inhomogeneous which lead to the full parameter realization of a cylindrical cloak. As an example, a cloak working at VHF band is modeled and its invisibility behavior is demonstrated based on the solution of the node voltages distributions. Due to the non-resonant properties of the L-C elements, the broadband characteristic of the proposed cloaks is also evident.

  19. A self-assembled three-dimensional cloak in the visible

    KAUST Repository

    Mühlig, Stefan

    2013-08-07

    An invisibility cloak has been designed, realized and characterized. The cloak hides free-standing sub-wavelength three-dimensional objects at the short wavelength edge of the visible spectrum. By a bottom-up approach the cloak was self-assembled around the object. Such fabrication approach constitutes a further important step towards real world applications of cloaking; leaving the realm of curiosity. The cloak and the way it was fabricated opens an avenue for many spectacular nanooptical applications such as non-disturbing sensors and photo-detectors, highly efficient solar cells, or optical nanoantenna arrays with strongly suppressed cross-talk to mention only a few. Our results rely on the successful combination of concepts from various disciplines, i.e. chemistry, material science, and plasmonics. Consequently, this work will stimulate these fields by unraveling new paths for future research.

  20. Occupants' satisfaction toward building environmental quality: structural equation modeling approach.

    Science.gov (United States)

    Kamaruzzaman, Syahrul Nizam; Egbu, C O; Zawawi, Emma Marinie Ahmad; Karim, Saipol Bari Abd; Woon, Chen Jia

    2015-05-01

    It is accepted that occupants who are more satisfied with their workplace's building internal environment are more productive. The main objective of the study was to measure the occupants' level of satisfaction and the perceived importance of the design or refurbishment on office conditions. The study also attempted to determine the factors affecting the occupants' satisfaction with their building or office conditions. Post-occupancy evaluations were conducted using a structured questionnaire developed by the Built Environment Research Group at the University of Manchester, UK. Our questionnaires incorporate 22 factors relating to the internal environment and rate these in terms of "user satisfaction" and "degree of importance." The questions were modified to reflect the specific setting of the study and take into consideration the local conditions and climate in Malaysia. The overall mean satisfaction of the occupants toward their office environment was 5.35. The results were measured by a single item of overall liking of office conditions in general. Occupants were more satisfied with their state of health in the workplace, but they were extremely dissatisfied with the distance away from a window. The factor analysis divided the variables into three groups, namely intrusion, air quality, and office appearance. Structural equation modeling (SEM) was then used to determine which factor had the most significant influence on occupants' satisfaction: appearance. The findings from the study suggest that continuous improvement in aspects of the building's appearance needs to be supported with effective and comprehensive maintenance to sustain the occupants' satisfaction.

  1. Objects cloaking in LWIR region by using a high efficiency infrared pixel

    Directory of Open Access Journals (Sweden)

    Arab

    2016-12-01

    Full Text Available This article, introduces a new pixel which can emit infrared wavelengths from its surface and can be used for the purpose of cloaking objects from thermal cameras. This pixel can simulate the temperatures between 0 and 100ºC emited from an infrared radiation in LWIR (8-12 micrometres region. Nanocomposite material is used in the pixel structure and this has increased its capacities like ZT factor %40-50 better than the commercial material like Bi2Te3. Technical aspects of the pixel such as the emission wavelengths, rate of temperature changing, thermal contrast, ZT factor and so on are discussed in this paper and were determined by using thermography, non-contact thermometry, radiometry, four probe ac method and temperature differential

  2. Structural control and health monitoring of building structures with unknown ground excitations: Experimental investigation

    Science.gov (United States)

    He, Jia; Xu, You-Lin; Zhan, Sheng; Huang, Qin

    2017-03-01

    When health monitoring system and vibration control system both are required for a building structure, it will be beneficial and cost-effective to integrate these two systems together for creating a smart building structure. Recently, on the basis of extended Kalman filter (EKF), a time-domain integrated approach was proposed for the identification of structural parameters of the controlled buildings with unknown ground excitations. The identified physical parameters and structural state vectors were then utilized to determine the control force for vibration suppression. In this paper, the possibility of establishing such a smart building structure with the function of simultaneous damage detection and vibration suppression was explored experimentally. A five-story shear building structure equipped with three magneto-rheological (MR) dampers was built. Four additional columns were added to the building model, and several damage scenarios were then simulated by symmetrically cutting off these columns in certain stories. Two sets of earthquakes, i.e. Kobe earthquake and Northridge earthquake, were considered as seismic input and assumed to be unknown during the tests. The structural parameters and the unknown ground excitations were identified during the tests by using the proposed identification method with the measured control forces. Based on the identified structural parameters and system states, a switching control law was employed to adjust the current applied to the MR dampers for the purpose of vibration attenuation. The experimental results show that the presented approach is capable of satisfactorily identifying structural damages and unknown excitations on one hand and significantly mitigating the structural vibration on the other hand.

  3. Design and analysis of the trapeziform and flat acoustic cloaks with controllable invisibility performance in a quasi-space

    Directory of Open Access Journals (Sweden)

    Jian Zhu

    2015-07-01

    Full Text Available We present the design, implementation and detailed performance analysis for a class of trapeziform and flat acoustic cloaks. An effective large invisible area is obtained compared with the traditional carpet cloak. The cloaks are realized with homogeneous metamaterials which are made of periodic arrangements of subwavelength unit cells composed of steel embedded in air. The microstructures and its effective parameters of the cloaks are determined quickly and precisely in a broadband frequency range by using the effective medium theory and the proposed parameters optimization method. The invisibility capability of the cloaks can be controlled by the variation of the key design parameters and scale factor which are proved to have more influence on the performance in the near field than that in the far field. Different designs are suitable for different application situations. Good cloaking performance demonstrates that such a device can be physically realized with natural materials which will greatly promote the real applications of invisibility cloak.

  4. The building block approach to airborne pod structures

    Science.gov (United States)

    Johansson, Jan D.

    2011-05-01

    The certification and testing of new airborne structures is a costly undertaking. This paper presents which measures can be taken to limit the cost and certification required in order to improve the capabilities of the current airborne as-sets, by applying a building block approach to the design and certification of airborne pod structures. A simple way of improving aircraft capabilities is by adding external pod structures, which has been performed for many applications over many years. However, this paper describes a truly modular approach, in which a typical airborne pod structure may be reconfigured to many various roles, with only limited re-certification requirements. Using existing or general aerodynamic shapes, the basic outer shape for the external store is defined, which is then combined with a modular substructure which can accommodate a large variety of electronic and/or optical sensors. This also allows the airborne pod structure to perform several intelligence collecting operations during the same sortie, thereby limiting the time spent near the danger area. The re-use of existing substructure modules reduces the cost and leadtime of the design phase allowing for a rapid entry into service. The modular design, relying on proven interface systems between the building blocks, significantly reduces risk involved in new programs. The certification process is also discussed in order to optimize the use of the pod structure modularity and certification requirements in order to simplify the certification task, by drawing similarity to existing designs. Finally the paper covers how modularity is implemented in new composite pod designs with stealth capabilities.

  5. FRF-based structural damage detection of controlled buildings with podium structures: Experimental investigation

    Science.gov (United States)

    Xu, Y. L.; Huang, Q.; Zhan, S.; Su, Z. Q.; Liu, H. J.

    2014-06-01

    How to use control devices to enhance system identification and damage detection in relation to a structure that requires both vibration control and structural health monitoring is an interesting yet practical topic. In this study, the possibility of using the added stiffness provided by control devices and frequency response functions (FRFs) to detect damage in a building complex was explored experimentally. Scale models of a 12-storey main building and a 3-storey podium structure were built to represent a building complex. Given that the connection between the main building and the podium structure is most susceptible to damage, damage to the building complex was experimentally simulated by changing the connection stiffness. To simulate the added stiffness provided by a semi-active friction damper, a steel circular ring was designed and used to add the related stiffness to the building complex. By varying the connection stiffness using an eccentric wheel excitation system and by adding or not adding the circular ring, eight cases were investigated and eight sets of FRFs were measured. The experimental results were used to detect damage (changes in connection stiffness) using a recently proposed FRF-based damage detection method. The experimental results showed that the FRF-based damage detection method could satisfactorily locate and quantify damage.

  6. Horizontal cloaking and vertical reflection by transformation acoustics

    Directory of Open Access Journals (Sweden)

    Min Kyung Lee

    2013-05-01

    Full Text Available This investigation shows that if an acoustic metamaterial bounded by an external rectangle and an internal circular cavity is properly engineered by a set of transformation equations that satisfy certain requirements, it can virtually cloak an object against incoming acoustic waves in one direction and make an incoming wave along the orthogonal direction reflected by an object located inside its inner cavity. The specific transformation equations realizing the metamaterial are suggested and an analysis is carried out to investigate the wave phenomena taking place along the cavity boundary.

  7. Ambient Response Analysis of the Heritage Court Tower Building Structure

    DEFF Research Database (Denmark)

    Brincker, Rune; Andersen, Palle

    2000-01-01

    In this paper an ambient response analysis of the Heritage Court Building structure is presented. The work is a part of a blind test organized by Professor Carlos Ventura, University of British Columbia. The response data were analyses using two different techniques: a non-parametric based...... on Frequency Domain Decomposition (FDD), and a parametric technique working on the raw data in time domain, a data driven Stochastic Subspace Identification (SSI) algorithm. Both techniques identified 11 modes under 10 HZ. One case of three close modes and one case of two close modes were identified. For all...

  8. Ambient Response Analysis of the Heritage Court Tower Building Structure

    DEFF Research Database (Denmark)

    Brincker, Rune; Andersen, P.

    2000-01-01

    In this paper an ambient response analysis of the Heritage Court Building structure is presented. The work is a part of a blind test organised by Professor Carlos Ventura, University of British Columbia. The response data were analysed using two different techniques: a non-parametric based...... on Frequency Domain Decomposition (FDD), and a parametric technique working on the raw data in time domain, a data driven Stochastic Subspace Identification (SSI) algorithm. Both techniques identified 11 modes under 10 Hz. One case of three close modes and one case of two close modes were identified. For all...

  9. IRT in the investigation of buildings and historic structures

    Science.gov (United States)

    Avdelidis, Nicolas P.; Moropoulou, Antonia

    2004-04-01

    Although, the efficiency of IRT (infrared thermography) as a NDT & E technique in the literature it is well documented, in the investigation of historic structures, where a restoration or conservation treatment can cause irreversible damage to the structure, it is considered to be of most importance. IRT is a non-destructive investigation technique that can be widely used due to the outstanding advantages that offers in a number of applications and specifically in the assessment of structural materials and techniques. In the present work, both IRT approaches, passive and active, were used, depending on the application, for the investigation of traditional-historical materials and structures. IRT was applied on restoration and traditional-historic materials and structures for the evaluation of conservation interventions (materials and techniques) concerning cleaning of architectural surfaces, restoration of masonries by repair mortars, as well as the disclosure of tesserae on plastered mosaic surfaces. For this reason, diagnostic studies on historical sites and structures took place. Wherever necessary, the emissivity values of the investigated materials were taken into account, after their determination in the laboratory on representative samples. Furthermore, in order to obtain useful information from the IRT surveys various properties (thermal, optical, physical) of the examined materials were taken into account. The outcome of this work provides strong evidence that IRT is an effective technique for the evaluation of historic buildings and sites.

  10. Biomimetic antimicrobial cloak by graphene-oxide agar hydrogel.

    Science.gov (United States)

    Papi, Massimiliano; Palmieri, Valentina; Bugli, Francesca; De Spirito, Marco; Sanguinetti, Maurizio; Ciancico, Carlotta; Braidotti, Maria Chiara; Gentilini, Silvia; Angelani, Luca; Conti, Claudio

    2016-12-01

    Antibacterial surfaces have an enormous economic and social impact on the worldwide technological fight against diseases. However, bacteria develop resistance and coatings are often not uniform and not stable in time. The challenge is finding an antibacterial coating that is biocompatible, cost-effective, not toxic, and spreadable over large and irregular surfaces. Here we demonstrate an antibacterial cloak by laser printing of graphene oxide hydrogels mimicking the Cancer Pagurus carapace. We observe up to 90% reduction of bacteria cells. This cloak exploits natural surface patterns evolved to resist to microorganisms infection, and the antimicrobial efficacy of graphene oxide. Cell integrity analysis by scanning electron microscopy and nucleic acids release show bacteriostatic and bactericidal effect. Nucleic acids release demonstrates microorganism cutting, and microscopy reveals cells wrapped by the laser treated gel. A theoretical active matter model confirms our findings. The employment of biomimetic graphene oxide gels opens unique possibilities to decrease infections in biomedical applications and chirurgical equipment; our antibiotic-free approach, based on the geometric reduction of microbial adhesion and the mechanical action of Graphene Oxide sheets, is potentially not affected by bacterial resistance.

  11. Relations between constructive peculiarities and structural behavior in Venice buildings

    Directory of Open Access Journals (Sweden)

    Doglioni, F.

    2012-12-01

    Full Text Available Here we are synthetically describing some constructive peculiarities of Venice civil buildings, analyzing the relation with the features of their structural decay and behavior in the long run. We suppose Venetian buildings, especially those parts which are conceived to suit the lagoon environment, to have undergone an evolution made of some adjustments, which were based on the observation of damages in previous buildings. That is we suppose ancient builders to rely on their awareness of the behavior of structures yet to come, and to be able to forecast it in part. This process brought some building contrivances to perfection, as exclusive and enduring features of Venice, overcoming changes in style and architectural layout, till they grew into essential elements of a whole and adaptable “device”. This writing is meant for a concise interpretation of this device, which is the result of some research works carried out at Venice IUAV University.

    En este texto, se describen sintéticamente algunas peculiaridades de la edificación residencial de Venecia, analizando su relación con el abanico de problemas estructurales que caracterizan el comportamiento estructural del edificio a lo largo del tiempo. Se aventura la hipótesis que las construcciones venecianas y, en particular, algunos de sus detalles, concebidos específicamente para la laguna donde se enclava, han sido objeto de una adaptación evolutiva a través de la observación de los problemas estructurales de los edificios precedentes. Los alarifes venecianos aprendieron a tener en cuenta el comportamiento estructural posterior del edificio, que previeron en cierta medida. Este proceso ha llevado a perfeccionar algunos detalles constructivos exclusivos de Venecia que han perdurado en el tiempo, que han resistido impertérritos a mutaciones de estilo y de configuración arquitectónica, hasta constituir elementos esenciales de un aparato indivisible y adaptable cuya interpretaci

  12. Protection Measures for Buildings Based on Coordinating Action Theory of Ground, Foundation and Structure

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Based on the theory of coordinating action of building ground, foundation and structure, this paper presents a modified method for calculating additional stresses on buildings in mining areas by considering the joint effect of curvature deformation and horizontal deformation on buildings. It points out that for buildings over the coal pillar, it is advisable to soften the intermediate ground of buildings when they are affected by mining. For buildings over the goaf, it is preferable to soften the ground at both ends of buildings. In order to enhance the ability of a building to resist tensile deformation, the key measure is to reinforce the bottom foundation of the building. In addition, the concept of "angle of break of building" is proposed. It is because of this angle that the protecting coal pillar is left, which is a better solution than prevailing solutions The findings provide a more scientific basis for mining under buildings.

  13. Structure and Interactions of Isolated Biomolecular Building Blocks.

    Science.gov (United States)

    de Vries, Mattanjah

    2006-03-01

    We investigate biomolecular building blocks and their clusters with each other and with water on a single molecular level. The motivation is the need to distinguish between intrinsic molecular properties and those that result from the biological environment. This is achieved by a combination of laser desorption and jet cooling, applied to aromatic amino acids, small peptides containing those, nucleobases and nucleosides. This approach is coupled with a number of laser spectroscopic techniques, including resonant multi-photon ionization, spectral hole burning and infra-red ion-dip spectroscopy. We will discuss examples illustrating how information can be obtained on spatial structure of individual biomolecules, including peptide conformations and details of DNA base-pairing.

  14. Transformation-optics macroscopic visible-light cloaking beyond two dimensions

    CERN Document Server

    Chu, Chia-Wei; Lee, Chih Jie; Duan, Yubo; Tsai, Din Ping; Zhang, Baile; Luo, Yuan

    2014-01-01

    Transformation optics, a recent geometrical design strategy of controlling light by combining Maxwell's principles of electromagnetism with Einstein's general relativity, promises without precedent an invisibility cloaking device that can render a macroscopic object invisible in three dimensions. However, most previous proof-of-concept transformation-optics cloaking devices focused predominantly on two dimensions, whereas detection of a macroscopic object along its third dimension was always unfailing. Here, we report the first experimental demonstration of transformation-optics macroscopic visible-light cloaking beyond two dimensions. This almost-three-dimensional cloak exhibits three-dimensional (3D) invisibility for illumination near its center (i.e. with a limited field of view), and its ideal wide-angle invisibility performance is preserved in multiple two-dimensional (2D) planes intersecting in the 3D space. Both light ray trajectories and optical path lengths have been verified experimentally at the ma...

  15. Transformation cloaking and radial approximations for flexural waves in elastic plates

    CERN Document Server

    Brun, M; Jones, I S; Movchan, A B; Movchan, N V

    2014-01-01

    It is known that design of elastic cloaks is much more challenging than the design idea for acoustic cloaks, cloaks of electromagnetic waves or scalar problems of anti-plane shear. In this paper, we address fully the fourth-order problem and develop a model of a broadband invisibility cloak for channelling flexural waves in thin plates around finite inclusions. We also discuss an option to employ efficiently an elastic pre-stress and body forces to achieve such a result. An asymptotic derivation provides a rigorous link between the model in question and elastic wave propagation in thin solids. This is discussed in detail to show connection with non-symmetric formulations in vector elasticity studied in earlier work.

  16. Molding the flow of light with a magnetic field: plasmonic cloaking and directional scattering

    CERN Document Server

    Kort-Kamp, W J M; Pinheiro, F A; Farina, C

    2014-01-01

    We investigate electromagnetic scattering and plasmonic cloaking in a system composed by a dielectric cylinder coated with a magneto-optical shell. In the long-wavelength limit we demonstrate that the application of an external magnetic field can not only switch on and off the cloaking mechanism but also mitigate losses, as the absorption cross-section is shown to be minimal precisely at the cloaking operation frequency band. We also show that the angular distribution of the scattered radiation can be effectively controlled by applying an external magnetic field, allowing for a swift change in the scattering pattern. By demonstrating that these results are feasible with realistic, existing magneto-optical materials, such as graphene epitaxially grown on SiC, we suggest that magnetic fields could be used as an effective, versatile external agent to tune plasmonic cloaks and to dynamically control electromagnetic scattering in an unprecedented way, we hope that these results may find use in disruptive photonic ...

  17. Exterior optical cloaking and illusions by using active sources: A boundary element perspective

    Science.gov (United States)

    Zheng, H. H.; Xiao, J. J.; Lai, Y.; Chan, C. T.

    2010-05-01

    Recently, it was demonstrated that active sources can be used to cloak any objects that lie outside the cloaking devices [F. Guevara Vasquez, G. W. Milton, and D. Onofrei, Phys. Rev. Lett. 103, 073901 (2009)]. Here, we propose that active sources can create illusion effects so that an object outside the cloaking device can be made to look like another object. Invisibility is a special case in which the concealed object is transformed to a volume of air. From a boundary element perspective, we show that active sources can create a nearly “silent” domain which can conceal any objects inside and at the same time make the whole system look like an illusion of our choice outside a virtual boundary. The boundary element method gives the fields and field gradients, which can be related to monopoles and dipoles, on continuous curves which define the boundary of the active devices. Both the cloaking and illusion effects are confirmed by numerical simulations.

  18. A Review of Current Researches on Blast Load Effects on Building Structures in China

    Institute of Scientific and Technical Information of China (English)

    LI Zhongxian; DU Hao; BAO Chunxiao

    2006-01-01

    The damages of building structures subjected to multifarious explosions cause huge losses of lives and property.It is the reason why the blast resistance and explosion protection of building structures become an important research topic in the civil engineering field all over the world.This paper provides an overview of the research work in China on blast loads effect on building structures.It includes modeling blast shock wave propagation and their effects,the dynamic responses of various building structures under blast loads and the measures to strengthen the building structures against blast loads.The paper also discusses the achievements and further work that needs be done for a better understanding of the blast loads' effects on building structures,and for deriving effective and economic techniques to design new or to strengthen existing structures.

  19. MUNI Ways and Structures Building Integrated Solar Membrane Project

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Randall

    2014-07-03

    The initial goal of the MUNI Ways and Structures Building Integrated Solar Membrane Installation Project was for the City and County of San Francisco (CCSF) to gain experience using the integrated higher efficiency solar photovoltaic (PV) single-ply membrane product, as it differs from the conventional, low efficiency, thin-film PV products, to determine the feasibility of success of larger deployment. As several of CCSF’s municipal rooftops are constrained with respect to weight restrictions, staff of the Energy Generation Group of the San Francisco Public Utilities Commission (SFPUC) proposed to install a solar PV system using single-ply membrane The installation of the 100 kW (DC-STC) lightweight photo voltaic (PV) system at the MUNI Ways and Structures Center (700 Pennsylvania Ave., San Francisco) is a continuation of the commitment of the City and County of San Francisco (CCSF) to increase the pace of municipal solar development, and serve its municipal facilities with clean renewable energy. The fourteen (14) solar photovoltaic systems that have already been installed at CCSF municipal facilities are assisting in the reduction of fossil-fuel use, and reduction of greenhouse gases from fossil combustion. The MUNI Ways & Structures Center roof has a relatively low weight-bearing capacity (3.25 pounds per square foot) and use of traditional crystalline panels was therefore rejected. Consequently it was decided to use the best available highest efficiency Building-Integrated PV (BIPV) technology, with consideration for reliability and experience of the manufacturer which can meet the low weight-bearing capacity criteria. The original goal of the project was to provide an opportunity to monitor the results of the BIPV technology and compare these results to other City and County of San Francisco installed PV systems. The MUNI Ways and Structures Center was acquired from the Cookson Doors Company, which had run the Center for many decades. The building was

  20. Principles of structure building in music, language and animal song.

    Science.gov (United States)

    Rohrmeier, Martin; Zuidema, Willem; Wiggins, Geraint A; Scharff, Constance

    2015-03-19

    Human language, music and a variety of animal vocalizations constitute ways of sonic communication that exhibit remarkable structural complexity. While the complexities of language and possible parallels in animal communication have been discussed intensively, reflections on the complexity of music and animal song, and their comparisons, are underrepresented. In some ways, music and animal songs are more comparable to each other than to language as propositional semantics cannot be used as indicator of communicative success or wellformedness, and notions of grammaticality are less easily defined. This review brings together accounts of the principles of structure building in music and animal song. It relates them to corresponding models in formal language theory, the extended Chomsky hierarchy (CH), and their probabilistic counterparts. We further discuss common misunderstandings and shortcomings concerning the CH and suggest ways to move beyond. We discuss language, music and animal song in the context of their function and motivation and further integrate problems and issues that are less commonly addressed in the context of language, including continuous event spaces, features of sound and timbre, representation of temporality and interactions of multiple parallel feature streams. We discuss these aspects in the light of recent theoretical, cognitive, neuroscientific and modelling research in the domains of music, language and animal song.

  1. Dispersion characteristics of silicon nanorod based carpet cloaks.

    Science.gov (United States)

    Tamma, Venkata A; Blair, John; Summers, Christopher J; Park, Wounjhang

    2010-12-06

    A wide range of transformation media designed with conformal mapping are currently being studied extensively due to their favorable properties: isotropy, moderate index requirements, low loss and broad bandwidth. For optical frequency operation, the transformation media are commonly fabricated on high index semiconductor thin films. These 2D implementations, however, inevitably introduces waveguide dispersion, which affects the bandwidth and loss behavior. In this paper, for carpet cloaks implemented by a silicon nanorod array, we have confirmed that waveguide dispersion limits the bandwidth of the transformation medium by direct visualizing the cut-off conditions with near-field scanning optical microscopy (NSOM). Furthermore, we have experimentally demonstrated the extension of cut-off wavelength by depositing a conformal dielectric layer. This study illustrates the constraints on the 2D transformation media imposed by the waveguide dispersion and suggests a general technique to tune and modify their optical properties.

  2. Omnidirectional transformation-optics cloak made from lenses and glenses.

    Science.gov (United States)

    Tyc, Tomáš; Oxburgh, Stephen; Cowie, Euan N; Chaplain, Gregory J; Macauley, Gavin; White, Chris D; Courtial, Johannes

    2016-06-01

    We present a design for an omnidirectional transformation-optics (TO) cloak comprising thin lenses and glenses (generalized thin lenses) [J. Opt. Soc. Am. A33, 962 (2016)1084-7529JOAOD610.1364/JOSAA.33.000962]. It should be possible to realize such devices in pixelated form. Our design is a piecewise nonaffine generalization of piecewise affine pixelated-TO devices [Proc. SPIE9193, 91931E (2014)PSISDG0277-786X10.1117/12.2061404; J. Opt18, 044009 (2016)]. It is intended to be a step in the direction of TO devices made entirely from lenses, which should be readily realizable on large length scales and for a broad range of wavelengths.

  3. How to Build Your Network? A Structural Analysis

    CERN Document Server

    Moskvina, Anastasia

    2016-01-01

    Creating new ties in a social network facilitates knowledge exchange and affects positional advantage. In this paper, we study the process, which we call network building, of establishing ties between two existing social networks in order to reach certain structural goals. We focus on the case when one of the two networks consists only of a single member and motivate this case from two perspectives. The first perspective is socialization: we ask how a newcomer can forge relationships with an existing network to place herself at the center. We prove that obtaining optimal solutions to this problem is NP-complete, and present several efficient algorithms to solve this problem and compare them with each other. The second perspective is network expansion: we investigate how a network may preserve or reduce its diameter through linking with a new node, hence ensuring small distance between its members. We give two algorithms for this problem. For both perspectives the experiment demonstrates that a small number of...

  4. Constitutive Parameters of Metamaterial Structures Used for Invisible Cloak Realization

    Science.gov (United States)

    2013-10-01

    OF ABSTRACT SAR 18, NUMBER OF PAGES 83 19a. NAME OF RESPONSIBLE PERSON Victor Putz a. REPORT UNCLAS b. ABSTRACT UNCLAS c. THIS...polarization). (a) (b) Figure 3.8. (a) Normalized bistatic scattering width (TMz and TEz polarizations) and (b) electric field

  5. Agent Types and Structures based on Analysis of Building Design

    DEFF Research Database (Denmark)

    Hartvig, Susanne C

    1997-01-01

    Based on an anaysis of building design an initial division of design agent into five classes: information collectors, generators, modifiers amd evaluators is presented.......Based on an anaysis of building design an initial division of design agent into five classes: information collectors, generators, modifiers amd evaluators is presented....

  6. Rigidly framed earth retaining structures thermal soil structure interaction of buildings supporting unbalanced lateral earth pressures

    CERN Document Server

    Aboumoussa, Walid

    2014-01-01

    Structures placed on hillsides often present a number of challenges and a limited number of economical choices for site design. An option sometimes employed is to use the building frame as a retaining element, comprising a Rigidly Framed Earth Retaining Structure (RFERS). The relationship between temperature and earth pressure acting on RFERS, is explored in this monograph through a 4.5 year monitoring program of a heavily instrumented in service structure. The data indicated that the coefficient of earth pressure behind the monitored RFERS had a strong linear correlation with temperature. The study also revealed that thermal cycles, rather than lateral earth pressure, were the cause of failure in many structural elements. The book demonstrates that depending on the relative stiffness of the retained soil mass and that of the structural frame, the developed lateral earth pressure, during thermal expansion, can reach magnitudes several times larger than those determined using classical earth pressure theories....

  7. Infrared Cloaking, Stealth, and the Second Law of Thermodynamics

    Directory of Open Access Journals (Sweden)

    Daniel P. Sheehan

    2012-10-01

    Full Text Available Infrared signature management (IRSM has been a primary aeronautical concern for over 50 years. Most strategies and technologies are limited by the second law of thermodynamics. In this article, IRSM is considered in light of theoretical developments over the last 15 years that have put the absolute status of the second law into doubt and that might open the door to a new class of broadband IR stealth and cloaking techniques. Following a brief overview of IRSM and its current thermodynamic limitations, theoretical and experimental challenges to the second law are reviewed. One proposal is treated in detail: a high power density, solid-state power source to convert thermal energy into electrical or chemical energy. Next, second-law based infrared signature management (SL-IRSM strategies are considered for two representative military scenarios: an underground installation and a SL-based jet engine. It is found that SL-IRSM could be technologically disruptive across the full spectrum of IRSM modalities, including camouflage, surveillance, night vision, target acquisition, tracking, and homing.

  8. Vibrations in a Multi-Storey Lightweight Building Structure

    DEFF Research Database (Denmark)

    Andersen, Lars Vabbersgaard; Kirkegaard, Poul Henning

    2013-01-01

    This paper provides a quantification of the changes in vibration level that can be expected in a lightweight multi-storey wooden building due to reduced connection stiffness or added nonstructural mass. Firstly, the impact of changes in the floor-to-wall connections is examined. Secondly, a study...... is performed regarding variations of the vibration level due to different placements of nonstructural mass inside the building. The analyses are carried out by means of a modular three-dimensional finite-element model. Each floor and wall panel is modelled in high detail, including door and window openings...

  9. Cloaks and antiobject-independent illusion optics based on illusion media

    Science.gov (United States)

    Li, Zhou; Zang, XiaoFei; Cai, Bin; Shi, Cheng; Zhu, YiMing

    2013-11-01

    Based on the transformation optics, we propose a new strategy of illusion media consisting of homogeneous and anisotropic materials. By utilizing the illusion media, invisible cloak is theoretically realized, in which objects covered with the illusion media could not be detected. The cloak here allows neither the propagation of light around the concealed region nor compensates the scattering field of object outside the media. What the cloak does is to shift the region into another place where outside the trace of light, so that objects in that region can disappear. Another application of the illusion media is to create the antiobject-independent illusion optics which means that two objects appear to be like some other objects of our choice. Finite element simulations for two-dimensional cases have been performed to prove these ideas.

  10. ANALYSIS OF SUFFICIENCY OF THE BEARING CAPACITY OF BUILDING STRUCTURES OF OPERATING SITES OF MAIN BUILDINGS OF THERMAL POWER PLANTS

    Directory of Open Access Journals (Sweden)

    Alekseeva Ekaterina Leonidovna

    2012-10-01

    Full Text Available Upon examination of eleven main buildings of power plants, analysis of defects and damages of building structures was performed. Thereafter, the damageability of principal bearing structures of main buildings of thermal plants was analyzed. It was identified that the fastest growing defects and damages were concentrated in the structures of operating sites. The research of the rate of development of the most frequent damages and defects made it possible to conclude that internal corrosion of the reinforcing steel was the most dangerous defect, as far as the reinforced concrete elements of operating sites were concerned. Methods of mathematical statistics were applied to identify the reinforcing steel development pattern inside reinforced concrete elements of floors of operating sites. It was identified that the probability of corrosion of reinforced concrete elements of operating sites was distributed in accordance with the demonstrative law. Based on these data, calculation of strength of reinforced concrete slabs and metal beams was performed in terms of their regular sections, given the natural loads and the realistic condition of structures. As a result, dependence between the bearing capacity reserve ratio and the corrosion development pattern was identified for reinforced concrete slabs and metal beams of operating sites. In order to analyze the sufficiency of the bearing capacity of building structures of operating sites in relation to their time in commission, equations were derived to identify the nature of dependence between the sufficiency of the bearing capacity of reinforced concrete slabs and metal beams of the operating sites and their time in commission.

  11. Metal-oxide based nanoobjects: reactivity, building blocks for polymeric structures and structural variety

    Science.gov (United States)

    Müller, Achim; Roy, Soumyajit

    2002-12-01

    From the unique 'library' of molybdenum-oxide based building blocks/fragments under reducing conditions in aqueous solution a huge variety of nanoobjects, allowing specific reactions at well-defined positions, can be generated. This enables us to perform a new type of nanochemistry. Examples include the well-known molecular big-wheel of the type {Mo176} and big-ball of the type {Mo132} including their derivatives which are considered here. In addition, the by far largest structurally well-characterised cluster having 368 molybdenum atoms with the shape of a lemon is outlined and discussed. The bibliography includes 71 references.

  12. Magnetization of Steel Building Materials and Structures in the Natural Geomagnetic Field

    Directory of Open Access Journals (Sweden)

    E. Čermáková

    2005-01-01

    Full Text Available This paper presents the physical basis of the magnetic properties of ferromagnetic materials and shows their relationships with external geomagnetic field. It graphically processes the experimental data detected by an HMR magnetometer. Taking into account the natural geomagnetic field under the effects of steel U profiles, variations of the natural geomagnetic field in a steel structure building are indicated and the potential existence of Sick Building Syndrome (SBS in these types of buildings is pointed out. 

  13. Systemic Thinking on the Building of Enterprises' "Three Cycle" Integration Structure

    Institute of Scientific and Technical Information of China (English)

    BaoshanLi; MinghuiQian

    2004-01-01

    Taking into consideration the characteristics of nowadays society, this paper has advanced the systemic thinking on the building of Enterprises' "Three Cycle" Integration Structure. After pointing out, the principles of optimization between theoretic structure and executive structure, this paper has brought forward the Enterprises' "Three Cycle" Integration Structure and its inherent relationship among each cycle.

  14. Building Footprints - MO 2011 Lincoln Structure Footprints (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Missouri Structure Footprints are structure footprints generated as polygons from a two pass look over the 2007 State 2ft imagery. Unlike the structure points, the...

  15. Building Footprints - MO 2011 Warren Structure Footprints (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Missouri Structure Footprints are structure footprints generated as polygons from a two pass look over the 2007 State 2ft imagery. Unlike the structure points, the...

  16. Building Footprints - MO 2011 Montgomery Structure Footprints (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Missouri Structure Footprints are structure footprints generated as polygons from a two pass look over the 2007 State 2ft imagery. Unlike the structure points, the...

  17. Optic-null space medium for cover-up cloaking without any negative refraction index materials

    Science.gov (United States)

    Sun, Fei; He, Sailing

    2016-07-01

    With the help of optic-null medium, we propose a new way to achieve invisibility by covering up the scattering without using any negative refraction index materials. Compared with previous methods to achieve invisibility, the function of our cloak is to cover up the scattering of the objects to be concealed by a background object of strong scattering. The concealed object can receive information from the outside world without being detected. Numerical simulations verify the performance of our cloak. The proposed method will be a great addition to existing invisibility technology.

  18. Time gap for temporal cloak based on spectral hole burning in atomic medium

    Science.gov (United States)

    Jabar, M. S. Abdul; Bacha, Bakht Amin; Ahmad, Iftikhar

    2016-08-01

    We demonstrate the possibility of creating a time gap in the slow light based on spectral hole burning in a four-level Doppler broadened sodium atomic system. A time gap is also observed between the slow and the fast light in the hole burning region and near the burnt hole region, respectively. A cloaking time gap is attained in microseconds and no distortion is observed in the transmitted pulse. The width of the time gap is observed to vary with the inverse Doppler effect in this system. Our results may provide a way to create multiple time gaps for a temporal cloak. Project supported by the Higher Education Commission (HEC) of Pakistan.

  19. Optic-null space medium for cover-up cloaking without any negative refraction index materials.

    Science.gov (United States)

    Sun, Fei; He, Sailing

    2016-07-07

    With the help of optic-null medium, we propose a new way to achieve invisibility by covering up the scattering without using any negative refraction index materials. Compared with previous methods to achieve invisibility, the function of our cloak is to cover up the scattering of the objects to be concealed by a background object of strong scattering. The concealed object can receive information from the outside world without being detected. Numerical simulations verify the performance of our cloak. The proposed method will be a great addition to existing invisibility technology.

  20. Eurocodes and the structural safety of existing buildings - Considering the publication of the Dutch NEN 8700

    NARCIS (Netherlands)

    Scholten, N.P.M.; Vrouwenvelder, A.C.W.M.

    2009-01-01

    Since 1992 there have been a number of proposals to renew calculation methods available to assess the structural safety of existing buildings. But without operational results. Upon publication of the Eurocodes NL decided to renew and to include them in the Dutch building regulations. The question wa

  1. VIBRATION OF FRAME BUILDING STRUCTURES CAUSED BY UNDERGROUND TRAINS

    Directory of Open Access Journals (Sweden)

    P. V. Аliavdin

    2011-01-01

    Full Text Available The paper contains investigations on element vibration of a real residential 9-storeyed reinforced-concrete frame building induced by train movement in the shallow subway. A design model for a problem on propagation of bending waves within the limits of the typical fragment of a skeleton is presented in the paper. The steady state vibrations of a column and reinforced-concrete slab induced by an excited force which is equivalent to the impact of the subway trains have been investigated in the paper. The problem has been solved numerically on the basis of the ANSYS FEA program. Numerical results have been compared with an approximate analytical solution and data on full-scale experiment. A prediction technique for vibration propagation in the designed buildings is offered in the paper. 

  2. Formation and erosion of biogeomorphological structures: A model study on the tube-building polychaete

    NARCIS (Netherlands)

    Borsje, B.W.; Bouma, T.J.; Rabaut, M.; Herman, P.M.J.; Hulscher, S.J.M.H.; Borsje, B.W.; Herman, P.M.J.

    2014-01-01

    We study how organism traits and population densities of ecosystem engineering species, in combination withenvironmental factors, affect the formation and erosion rates of biogeomorphological structures, and focus on thewidely distributed marine tube-building polychaete Lanice conchilega, which live

  3. System identification of a building alone with the effect of dynamic soil-structure interaction eliminated

    Energy Technology Data Exchange (ETDEWEB)

    Naito, Yukio [Kajima Corp., Kajima Technical Research Institute, Tokyo (Japan); Yano, Tatsuo [Kajima Corp., Nuclear Power Department, Tokyo (Japan); Iguchi, Michio [Science Univ. of Tokyo, Faculty of Science and Technology, Noda, Chiba (Japan); Kitada, Yoshio [Nuclear Power Engineering Corp., Tokyo (Japan)

    2003-02-01

    High-rigidity and heavy buildings such as reactor buildings usually have large soil-structure interaction effect in its dynamic response. In such cases, spectrum ratio of the top of the building to the bottom for horizontal motion gives different result from the dynamic characteristics of the building under fixed-base condition because the effect of the rocking motion of the base is not eliminated. This paper presented a new method for such problems; applied it to a ground blast vibration, microtremors and forced vibration test results; and transfer functions of the building for fixed-base condition were obtained. The proposed method can be applied when the exciter is set at the upper part of the buildings. (author)

  4. Building Points - Montana Structures/Addresses Framework - Web Service

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Map service for the Montana Structures MSDI Framework. The service will only display at scales of 1:100,000 or larger. Structures are grouped into general categories...

  5. Building Footprints - MO 2012 St. Genevieve Structure Footprints (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed categorized polygons on all roofed structures larger than standard domicile structure size at a scale of 1:2000 using...

  6. Building Footprints - MO 2012 Bollinger Structure Footprints (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed categorized polygons on all roofed structures larger than standard domicile structure size at a scale of 1:2000 using...

  7. Building Footprints - MO 2012 Cape Girardeau Structure Footprints (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed categorized polygons on all roofed structures larger than standard domicile structure size at a scale of 1:2000 using...

  8. Building Footprints - MO 2012 Iron Structure Footprints (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed categorized polygons on all roofed structures larger than standard domicile structure size at a scale of 1:2000 using...

  9. Building Footprints - MO 2012 Madison Structure Footprints (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed categorized polygons on all roofed structures larger than standard domicile structure size at a scale of 1:2000 using...

  10. Building Footprints - MO 2012 Perry Structure Footprints (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed categorized polygons on all roofed structures larger than standard domicile structure size at a scale of 1:2000 using...

  11. Composite structures of steel and concrete beams, slabs, columns, and frames for buildings

    CERN Document Server

    Johnson, R P

    2008-01-01

    This book sets out the basic principles of composite construction with reference to beams, slabs, columns and frames, and their applications to building structures. It deals with the problems likely to arise in the design of composite members in buildings, and relates basic theory to the design approach of Eurocodes 2, 3 and 4.The new edition is based for the first time on the finalised Eurocode for steel/concrete composite structures.

  12. The integration of water loop heat pump and building structural thermal storage systems

    Energy Technology Data Exchange (ETDEWEB)

    Marseille, T.J.; Schliesing, J.S.

    1991-10-01

    Many commercial buildings need heat in one part and, at the same time, cooling in another part. Even more common is the need for heating during one part of the day and cooling during another in the same spaces. If that energy could be shifted or stored for later use, significant energy might be saved. If a building's heating and cooling subsystems could be integrated with the building's structural mass and used to collect, store, and deliver energy, the energy might be save cost-effectively. To explore this opportunity, researchers at the Pacific Northwest Laboratory (PNL) examined the thermal interactions between the heating, ventilating, and air-conditioning (HVAC) system and the structure of a commercial building. Computer models were developed to simulate the interactions in an existing building located in Seattle, Washington, to determine how these building subsystems could be integrated to improve energy efficiency. The HVAC subsystems in the existing building were modeled. These subsystems consist of decentralized water-source heat pumps (WSHP) in a closed water loop, connected to cooling towers for heat rejection during cooling mode and boilers to augment heating. An initial base case'' computer model of the Seattle building, as-built, was developed. Metered data available for the building were used to calibrate this model to ensure that the analysis would provide information that closely reflected the operation of a real building. The HVAC system and building structure were integrated in the model using the concrete floor slabs as thermal storage media. The slabs may be actively charged during off-peak periods with the chilled water in the loop and then either actively or passively discharged into the conditioned space during peak periods. 21 refs., 37 figs., 17 tabs.

  13. Rainbow and blueshift effect of a dispersive spherical invisibility cloak impinged on by a nonmonochromatic plane wave.

    Science.gov (United States)

    Zhang, Baile; Wu, Bae-Ian; Chen, Hongsheng; Kong, Jin Au

    2008-08-08

    We demonstrate some interesting phenomena associated with a nonmonochromatic plane wave passing through a spherical invisibility cloak whose radial permittivity and permeability are of Drude and Lorentz types. We observe that the frequency center of a quasimonochromatic incident wave will suffer a blueshift in the forward scattering direction. Different frequency components have different depths of penetration, causing a rainbowlike effect within the cloak. The concept of group velocity at the inner boundary of the cloak needs to be revisited. Extremely low scattering can still be achieved within a narrow band.

  14. Beam Steering at Higher Photonic Bands and Design of a Directional Cloak Formed by Photonic Crystals

    Directory of Open Access Journals (Sweden)

    Venkatachalam Subramanian

    2013-02-01

    Full Text Available Beam steering due to anomalous dispersion at higher photonic bands in dielectric photonic crystal is reported in this work. Based on this concept, directional cloak is designed that conceals a larger dimensional scattering object against the normal incident, linearly polarizedelectromagnetic waves.

  15. Electromagnetic cloak to restore the antenna radiation patterns affected by nearby scatter

    Science.gov (United States)

    Teperik, Tatiana V.; de Lustrac, André

    2015-12-01

    We have theoretically verified the feasibility of the concept of mantle cloak for very high frequency (VHF) antenna communications. While the applicability of the concept has been demonstrated for an infinitely long cylindrical obstacle and infinitely long electric source [Y.R. Padooru, A.B. Yakovlev, and P.-Y. Chen and Andrea Alù, J. Appl. Phys., 112, 104902, (2012)], the use of this cloak in realistic conditions is not straightforward. In this paper as an electric source we consider a typical VHF monopole antenna mounted on ground plane together with a metallic cylindrical obstacle. The both ground plane and obstacle affect the antenna radiation scattering. Nevertheless, we could show that the mantle cloak can bee successfully applied to restore the radiation patterns of antenna even when the source, the cylindrical metallic obstacle, and the ground plane have finite length. We have studied the antenna adaptation in the presence of the cloaked obstacle and found that the complete radiation system is still functional in the bandwidth that is reduced only by 11%.

  16. Electromagnetic cloak to restore the antenna radiation patterns affected by nearby scatter

    Energy Technology Data Exchange (ETDEWEB)

    Teperik, Tatiana V., E-mail: tatiana.teperik@u-psud.fr [Univ. Paris-Sud, Institut d’Electronique Fondamentale, UMR 8622, Orsay F-91405 (France); Donostia International Physics Center, Aptdo. 1072, 20080 San Sebastian (Spain); Lustrac, André de [Univ. Paris-Sud, Institut d’Electronique Fondamentale, UMR 8622, Orsay F-91405 (France); Univ. Paris-Ouest, 92410 Ville d’Avray (France)

    2015-12-15

    We have theoretically verified the feasibility of the concept of mantle cloak for very high frequency (VHF) antenna communications. While the applicability of the concept has been demonstrated for an infinitely long cylindrical obstacle and infinitely long electric source [Y.R. Padooru, A.B. Yakovlev, and P.-Y. Chen and Andrea Alù, J. Appl. Phys., 112, 104902, (2012)], the use of this cloak in realistic conditions is not straightforward. In this paper as an electric source we consider a typical VHF monopole antenna mounted on ground plane together with a metallic cylindrical obstacle. The both ground plane and obstacle affect the antenna radiation scattering. Nevertheless, we could show that the mantle cloak can bee successfully applied to restore the radiation patterns of antenna even when the source, the cylindrical metallic obstacle, and the ground plane have finite length. We have studied the antenna adaptation in the presence of the cloaked obstacle and found that the complete radiation system is still functional in the bandwidth that is reduced only by 11%.

  17. Scattering suppression and wideband tunability of a flexible mantle cloak for finite-length conducting rods

    Science.gov (United States)

    Schofield, R. S.; Soric, J. C.; Rainwater, D.; Kerkhoff, A.; Alù, A.

    2014-06-01

    A simple, thin, flexible mantle cloak for conducting rods based on scattering cancellation is analyzed, designed and experimentally realized. We show strong scattering suppression at all angles of incidence, for both far-field plane-wave and near-field Gaussian excitations. The required effective shunt surface impedance is realized by a subwavelength patch array, targeting the suppression of the dominant omnidirectional scattering contribution of a conductive rod. Full-wave simulations predict a total radar cross-section reduction better than 14 dB in the lossless case and nearly 8 dB when considering a lossy substrate in the cover. Measurements of the realized cloak are consistent and validate these numerical predictions. The proposed geometry is also shown to be an ideal platform for monolithic integration of varactor diodes, allowing real-time tuning of the effective surface capacitance of the cloak. We show with numerical simulations the possibility of tunable scattering suppression over 1 GHz of bandwidth by seamlessly integrating varactor diodes in our mantle cloak design.

  18. HYPERSTATIC STRUCTURE MAPPING MODEL BUILDING AND OPTIMIZING DESIGN

    Institute of Scientific and Technical Information of China (English)

    XU Gening; GAO Youshan; ZHANG Xueliang; YANG Ruigang

    2007-01-01

    Hyperstatic structure plane model being built by structural mechanics is studied. Space model precisely reflected in real stress of the structure is built by finite element method (FEM) analysis commerce software. Mapping model of complex structure system is set up, with convenient calculation just as in plane model and comprehensive information as in space model. Plane model and space model are calculated under the same working condition. Plane model modular construction inner force is considered as input data; Space model modular construction inner force is considered as output data. Thus specimen is built on input data and output data. Character and affiliation are extracted through training specimen, with the employment of nonlinear mapping capability of the artificial neural network. Mapping model with interpolation and extrapolation is gained, laying the foundation for optimum design. The steel structure of high-layer parking system (SSHLPS) is calculated as an instance. A three-layer back-propagation (BP) net including one hidden layer is constructed with nine input nodes and eight output nodes for a five-layer SSHLPS. The three-layer structure optimization result through the mapping model interpolation contrasts with integrity re-analysis, and seven layers structure through the mapping model extrapolation contrasts with integrity re-analysis. Any layer SSHLPS among 1~8 can be calculated with much accuracy. Amount of calculation can also be reduced if it is applied into the same topological structure, with reduced distortion and assured precision.

  19. Developing Dynamic Digital Image Correlation Technique to Monitor Structural Damage of Old Buildings under External Excitation

    Directory of Open Access Journals (Sweden)

    Ming-Hsiang Shih

    2014-01-01

    Full Text Available The capacity of buildings to resist external excitation is an important factor to consider for the structural design of buildings. When subject to external excitation, a building may suffer a certain degree of damages, and its residual capacity to resist external excitation cannot be evaluated. In this research, dynamic digital image correlation method combined with parameter evaluation available in system identification is used to evaluate the structural capacity to resist external excitation. The results reveal possible building latent safety problems so that timely structural reinforcement or dismantling of the building can be initiated to alleviate further damages. The results of experiments using the proposed method conform to the results obtained using the conventional method, but this method is more convenient and rapid than the latter in the subsequent procedure of data processing. If only the frequency change is used, the damages suffered by the building can be detected, but the damage location is not revealed. The interstory drift mode shape (IDMS based on the characteristic of story drift has higher sensitivity than the approximate story damage index (ADSI method based on modal frequency and vibration type; however, both indices can be used to determine the degree and location of building damages.

  20. Structural system identification of buildings by a wave method based on a layered Timoshenko beam model

    Science.gov (United States)

    Ebrahimian, Mahdi; Todorovska, Maria I.

    2014-03-01

    A layered Timoshenko beam (TB) model of a high-rise building is presented and applied to system identification of a full-scale building from recorded seismic response. This model is a new development in a wave method for earthquake damage detection and structural health monitoring being developed by the authors' research group. The method is based on monitoring changes in the wave properties of the structure, such as the velocity of wave propagation vertically through the structure. This model is an improvement over the previously used layered shear beam (SB) model because it accounts for wave dispersion caused by flexural deformation present in addition to shear. It also accounts for the rotatory inertia and the variation of the building properties with height. The case study is a 54-story steel frame building located in downtown Los Angeles. Recorded accelerations during the Northridge earthquake of 1994 are used for system identification of the NS response. The model parameters are identified by matching, in the least squares sense, the model and observed impulse response functions at all levels where motion was recorded. The model is then used to compute the building vertical phase and group velocities. Impulse responses computed by deconvolution of the recorded motions with the roof response are used, which represent the building response to a virtual source at the roof. The better match of transfer-function amplitudes of the fitted TB model than of previously fitted SB model indicates that the layered TB model is a better physical model for this building.

  1. Building Points - MO 2014 Barton Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed attributed points on all roofed structures visible at a scale of 1:2000 using MSDIS-DOQQ 2008 2-foot aerial imagery...

  2. Building Points - MO 2014 Camden Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed attributed points on all roofed structures visible at a scale of 1:2000 using MSDIS-DOQQ 2008 2-foot aerial imagery...

  3. Building Points - MO 2014 Dade Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed attributed points on all roofed structures visible at a scale of 1:2000 using MSDIS-DOQQ 2008 2-foot aerial imagery...

  4. Building Points - MO 2014 Clark Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed attributed points on all roofed structures visible at a scale of 1:2000 using MSDIS-DOQQ 2008 2-foot aerial imagery...

  5. Building Points - MO 2014 Audrain Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed attributed points on all roofed structures visible at a scale of 1:2000 using MSDIS-DOQQ 2008 2-foot aerial imagery...

  6. Building Points - MO 2014 Bates Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed attributed points on all roofed structures visible at a scale of 1:2000 using MSDIS-DOQQ 2008 2-foot aerial imagery...

  7. Building Points - MO 2014 Benton Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed attributed points on all roofed structures visible at a scale of 1:2000 using MSDIS-DOQQ 2008 2-foot aerial imagery...

  8. Building Points - MO 2014 Butler Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed attributed points on all roofed structures visible at a scale of 1:2000 using MSDIS-DOQQ 2008 2-foot aerial imagery...

  9. Building Points - MO 2011 Lincoln Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — MSDIS staff identified and located all ?binary? structures and compiled them into a spatial database. Annual review and maintenance of the database will occur with...

  10. Building Points - MO 2012 St. Francois Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed categorized points on all roofed structures visible at a scale of 1:2000 using MSDIS-DOQQ 2008 2-foot aerial imagery...

  11. Building Points - MO 2012 Revised Boone Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — MSDIS staff provided project management and worked with the Mid-MO RPC to locate "structures" within their region. MSDIS staff identified and located all “binary”...

  12. Building Points - MO 2012 St. Genevieve Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed categorized points on all roofed structures visible at a scale of 1:2000 using MSDIS-DOQQ 2008 2-foot aerial imagery...

  13. Building Points - MO 2011 Warren Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — MSDIS staff identified and located all ?binary? structures and compiled them into a spatial database. Annual review and maintenance of the database will occur with...

  14. Building Points - MO 2011 Montgomery Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — MSDIS staff identified and located all ?binary? structures and compiled them into a spatial database. Annual review and maintenance of the database will occur with...

  15. Building Points - MO 2012 Perry Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed categorized points on all roofed structures visible at a scale of 1:2000 using MSDIS-DOQQ 2008 2-foot aerial imagery...

  16. Building Points - MO 2012 Cape Girardeau Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed categorized points on all roofed structures visible at a scale of 1:2000 using MSDIS-DOQQ 2008 2-foot aerial imagery...

  17. Building Points - MO 2012 Iron Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed categorized points on all roofed structures visible at a scale of 1:2000 using MSDIS-DOQQ 2008 2-foot aerial imagery...

  18. Building Points - MO 2012 Madison Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed categorized points on all roofed structures visible at a scale of 1:2000 using MSDIS-DOQQ 2008 2-foot aerial imagery...

  19. Building Points - MO 2012 Bollinger Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed categorized points on all roofed structures visible at a scale of 1:2000 using MSDIS-DOQQ 2008 2-foot aerial imagery...

  20. Building Points - MO 2014 Christian Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed attributed points on all roofed structures visible at a scale of 1:2000 using MSDIS-DOQQ 2008 2-foot aerial imagery...

  1. Building Points - MO 2014 Andrew Structure Points (SHP)

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Staff at the Geographic Resources Center placed attributed points on all roofed structures visible at a scale of 1:2000 using MSDIS-DOQQ 2008 2-foot aerial imagery...

  2. Integrating geomatics and structural investigation in post-earthquake monitoring of ancient monumental Buildings

    Science.gov (United States)

    Dominici, Donatella; Galeota, Dante; Gregori, Amedeo; Rosciano, Elisa; Alicandro, Maria; Elaiopoulos, Michail

    2014-06-01

    The old city center of L’Aquila is rich in historical buildings of considerable merit. On April 6th 2009 a devastating earthquake caused significant structural damages, affecting especially historical and monumental masonry buildings. The results of a study carried out on a monumental building, former headquarters of the University of L’Aquila (The Camponeschi building, XVI century) are presented in this paper. The building is situated in the heart of the old city center and was seriously damaged by the earthquake. Preliminary visual damage analysis carried out immediately after the quake, clearly evidenced the building’s complexity, raising the need for direct and indirect investigation on the structure. Several non-destructive test methods were then performed in situ to better characterize the masonry typology and the damage distribution, as well. Subsequently, a number of representative control points were identified on the building’s facades to represent, by their motion over time, the evolution of the structural displacements and deformations. In particular, a surveying network consisting of 27 different points was established. A robotic total station mounted on top of a concrete pillar was used for periodically monitoring the surveying control network. Stability of the pillar was checked through a GNSS static survey repeated before any set of measurements. The present study evidences the interesting possibilities of combining geomatics with structural investigation during post-earthquake monitoring of ancient monumental buildings.

  3. SEISMIC EVALUATION OF EXISTING MID-RISE REINFORCED CONCRETE BUILDINGS ACCORDING TO SPECIFICATION FOR BUILDING STRUCTURES TO BE BUILT IN DISASTER AREAS

    Directory of Open Access Journals (Sweden)

    Mehmet İNEL

    2007-01-01

    Full Text Available Over the past several decades, Turkey has been hit by devastating earthquakes and remarkable number of reinforced concrete buildings has been damaged in the high seismicity regions of our country. The aim of this study is to evaluate the seismic performance of the mid-rise reinforced concrete buildings that are major part of building stock of our earthquake-prone country, according to recent Turkish Earthquake Code. 4- and 7-story buildings were selected to represent mid-rise building stock. After determining the structural parameters, each building was subjected to pushover analysis and the capacity curves were obtained. Earthquake performance of each building was determined in the light of their capacity curves according to the recent Turkish Earthquake Code.

  4. The importance of building construction materials relative to other factors affecting structure survival during wildfire

    Science.gov (United States)

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

    2017-01-01

    Structure loss to wildfire is a serious problem in wildland-urban interface areas across the world. Laboratory experiments suggest that fire-resistant building construction and design could be important for reducing structure destruction, but these need to be evaluated under real wildfire conditions, especially relative to other factors. Using empirical data from destroyed and surviving structures from large wildfires in southern California, we evaluated the relative importance of building construction and structure age compared to other local and landscape-scale variables associated with structure survival. The local-scale analysis showed that window preparation was especially important but, in general, creating defensible space adjacent to the home was as important as building construction. At the landscape scale, structure density and structure age were the two most important factors affecting structure survival, but there was a significant interaction between them. That is, young structure age was most important in higher-density areas where structure survival overall was more likely. On the other hand, newer-construction structures were less likely to survive wildfires at lower density. Here, appropriate defensible space near the structure and accessibility to major roads were important factors. In conclusion, community safety is a multivariate problem that will require a comprehensive solution involving land use planning, fire-safe construction, and property maintenance.

  5. Influence of Structural Periodicity on Vibration Transmission in a Multi-Storey Wooden Building

    DEFF Research Database (Denmark)

    Andersen, Lars Vabbersgaard

    2013-01-01

    Noise is a nuisance to people, and buildings should therefore be designed to prevent propagation of sound and vibration in the audible frequency range as well as the range of frequencies relevant to whole-body vibrations of humans. In heavy structures made of concrete and masonry, a source...... with high energy content is required to mobilise the inertia. However, for lightweight building structures made of wood, less energy is required to produce vibrations since the mass is smaller. This leads to a high risk of sound and vibration propagation in terms of direct as well as flanking transmission....... Using a substructure approach, the panels are then combined to a global model of a multi-storey building. Example Eigen modes of a single floor panel and the global building are presented. Vibration caused by point force excitation is finally analysed in the frequency domain as well as the time domain....

  6. Automatic Generation of Structural Building Descriptions from 3D Point Cloud Scans

    DEFF Research Database (Denmark)

    Ochmann, Sebastian; Vock, Richard; Wessel, Raoul

    2013-01-01

    scans to derive high-level architectural entities like rooms and doors. Starting with a registered 3D point cloud, we probabilistically model the affiliation of each measured point to a certain room in the building. We solve the resulting clustering problem using an iterative algorithm that relies......We present a new method for automatic semantic structuring of 3D point clouds representing buildings. In contrast to existing approaches which either target the outside appearance like the facade structure or rather low-level geometric structures, we focus on the building’s interior using indoor...

  7. Optimization of time-delayed feedback control of seismically excited building structures

    Institute of Scientific and Technical Information of China (English)

    Xue-ping LI; Wei-qiu ZHU; Zu-guang YING

    2008-01-01

    An optimization method for time-delayed feedback control of partially observable linear building structures subjected to seismic excitation is proposed. A time-delayed control problem of partially observable linear building structure under horizontal ground acceleration excitation is formulated and converted into that of completely observable linear structure by using separation principle. The time-delayed control forces are approximately expressed in terms of control forces without time delay. The control system is then governed by Ito stochastic differential equations for the conditional means of system states and then transformed into those for the conditional means of modal energies by using the stochastic averaging method for quasi-Hamiltonian systems. The control law is assumed to be modal velocity feedback control with time delay and the unknown control gains are determined by the modal performance indices. A three-storey building structure is taken as example to illustrate the proposal method and the numerical results are confirmed by using Monte Carlo simulation.

  8. Quick assessment tool for assurance of structural safety in the building process

    NARCIS (Netherlands)

    Terwel, K.C.; Jansen, S.J.T.

    2014-01-01

    From forensic investigation it is known that many structural failures can be attributed to human errors and organizational factors. To provide project leaders with information on the current state of factors in the building process influencing structural safety, we developed a quick assessment tool.

  9. Cumulative and Segmented Learning: Exploring the Role of Curriculum Structures in Knowledge-Building

    Science.gov (United States)

    Maton, Karl

    2009-01-01

    The present article extends Basil Bernstein's theorisation of "discourses" and "knowledge structures" to explore the potential of educational knowledge structures to enable or constrain cumulative learning, where students can transfer knowledge across contexts and build knowledge over time. It offers a means of overcoming…

  10. Bilberry xyloglucan - novel building blocks containing ß-xylose within a complex structure

    NARCIS (Netherlands)

    Hilz, H.; Jong, de L.E.; Kabel, M.A.; Verhoef, R.P.; Schols, H.A.; Voragen, A.G.J.

    2007-01-01

    Bilberries are known to have one of the most complex xyloglucan structures described in the plant kingdom until now. To characterise this structure, xyloglucans were enzymatically degraded and the oligosaccharides obtained were analysed. More than 20 different building blocks were found to make up t

  11. Minimization of structure-borne noise in lightweight buildings

    DEFF Research Database (Denmark)

    Niu, Bin; Olhoff, Niels

    2012-01-01

    This paper deals with the problem of minimizing the structure-borne noise induced in a room by machinery vibration. A generalized system consisting of the machine, the base plate, resilient mounts, the floor plate and the room cavity is developed for analysis and optimization. Topological design...

  12. 基于主动声学超材料的圆柱声隐身斗篷设计研究%Research on a cylindrical cloak with active acoustic metamaterial layers

    Institute of Scientific and Technical Information of China (English)

    沈惠杰; 温激鸿; 郁殿龙; 蔡力; 温熙森

    2012-01-01

    Enlightened by the tunable properties of effective density of the active acoustic metamaterial, we design an active infinite cylinder acoustic cloak according to the idea of the multilayer structured acoustic cloak with homogeneous isotropic materials. Utilizing the electrical analog, the dynamical equation of the acoustic cavity with Piezo-Diaphragm is presented. By analyzing the circuit diagram, the control strategy of achieving various effective densities which are used for constructing the acoustic cloak is given. Based on the necessary parameters such as the wide range values of the relative densities gained by active control, and the acoustic speed of each composite layer, the acoustic pressure field of the plane wave incident on the cloak is calculated, via the FEM model. Also the pressure map of a rigid cylinder scatterer with surrounded fluid is performed for comparison. Results show that outside the cloaking shell, the plane wave field is almost undisturbed. However inside the shell, the plane wavefronts are gradually deflected, and guided around the cloaked domain, returning to the original plane shape with small perturbation. This phenomenon making the cloak acoustically invisible in some frequency ranges has useful values in engineering applications. Finally, the total scattering cross section of the cloak is calculated to investigate the invisible effect according to the frequency domain. The total number of the composite active metamaterial layers is 15, which is much easier to realize in experiment.%基于多层复合材料结构的二维卢隐身斗篷设计思想,利用主动隔膜声学空腔有效密度可以任意控制这一特性,设计了主动声学超材料下的无限长圆柱声隐身斗篷.给出了主动隔膜声学空腔单元的声电元件类比模拟电路图和具体的有效密度控制方法.进行了主动声学超材料声隐身斗篷的结构建模,并对平面入射波入射下此圆柱隐身斗篷周围声压分布场进

  13. Amino Acid Molecular Units: Building Primary and Secondary Protein Structures

    Directory of Open Access Journals (Sweden)

    Aparecido R. Silva

    2008-05-01

    Full Text Available In order to guarantee the learning quality and suitable knowledge  use  about structural biology, it is fundamental to  exist, since the beginning of  students’ formation, the possibility of clear visualization of biomolecule structures. Nevertheless, the didactic books can only bring  schematic  drawings; even more elaborated figures and graphic computation  do not permit the necessary interaction.  The representation of three-dimensional molecular structures with ludic models, built with representative units, have supplied to the students and teachers a successfully experience to  visualize such structures and correlate them to the real molecules.  The design and applicability of the representative units were discussed with researchers and teachers before mould implementation.  In this stage  it  will be presented the  developed  kit  containing the  representative  plastic parts of the main amino acids.  The kit can demonstrate the interaction among the amino acids  functional groups  (represented by colors, shapes,  sizes and  the peptidic bonds between them  facilitating the assembly and visuali zation of the primary and secondary protein structure.  The models were designed for  Ca,  amino,  carboxyl groups  and  hydrogen. The  lateral chains have  well defined models that represent their geometrical shape.  The completed kit set  will be presented in this meeting (patent requested.  In the last phase of the project will be realized  an effective evaluation  of the kit  as a facilitative didactic tool of the teaching/learning process in the Structural Molecular Biology area.

  14. Building a Data Store with the Dynamic Structure

    Directory of Open Access Journals (Sweden)

    Yu. N. Artamonov

    2016-01-01

    Full Text Available This article presents the analysis of approaches to data warehouse construction based on relational and NoSQL solutions and lists the limitations of the relational approach to data mining. The contradiction between data presentation in the real subject domain and the model of data presentation in the relational and NoSQL approaches is revealed. The revealed contradiction is related to the temporality of the values of individual data attributes, the variability of the composition of these attributes, and structure of connections between them. A new logical model of the data warehouse with dynamic structure is proposed. The model is based on the concept of the object as a container for properties storage. Each property of the object includes the property name and two property values without reference and with reference, that are relevant at a given time. The reference property value points to an object whose name is interpreted as the value of the property at a given time. A formal description of the model with allocation of the necessary functionality to manipulate objects and their properties (selectors, predicates, constructors is given and the necessary control structures are introduced. Substantiation of the proposed model, called an OP-model is given on the basis of compliance with the logical ER data model. It is proved that any ER data model can be implemented in the OP-model. At the same time, the advantages of the OP-model are indicated, they are associated with the possibility of changing connections between entities due to changes in the reference value at a particular time. The potential for scalability of data warehouse due to the unique identification of each object is noted. 

  15. Seismic design or retrofit of buildings with metallic structural fuses by the damage-reduction spectrum

    Science.gov (United States)

    Li, Gang; Jiang, Yi; Zhang, Shuchuan; Zeng, Yan; Li, Qiang

    2015-03-01

    Recently, the structural fuse has become an important issue in the field of earthquake engineering. Due to the trilinearity of the pushover curve of buildings with metallic structural fuses, the mechanism of the structural fuse is investigated through the ductility equation of a single-degree-of-freedom system, and the corresponding damage-reduction spectrum is proposed to design and retrofit buildings. Furthermore, the controlling parameters, the stiffness ratio between the main frame and structural fuse and the ductility factor of the main frame, are parametrically studied, and it is shown that the structural fuse concept can be achieved by specific combinations of the controlling parameters based on the proposed damage-reduction spectrum. Finally, a design example and a retrofit example, variations of real engineering projects after the 2008 Wenchuan earthquake, are provided to demonstrate the effectiveness of the proposed design procedures using buckling restrained braces as the structural fuses.

  16. Towards composite spheres as building blocks for structured molecules

    Science.gov (United States)

    Lee, Lloyd L.; Pellicane, Giuseppe

    2016-10-01

    In order to design a flexible molecular model that mimics the chemical moieties of a polyatomic molecule, we propose the ‘composite-sphere’ model that can assemble the essential elements to produce the structure of the target molecule. This is likened to the polymerization process where monomers assemble to form the polymer. The assemblage is built into the pair interaction potentials which can ‘react’ (figuratively) with selective pieces into various bonds. In addition, we preserve the spherical symmetries of the individual pair potentials so that the isotropic Ornstein-Zernike equation (OZ) for multi-component mixtures can be used as a theoretical framework. We first test our approach on generating a dumbbell molecule. An equimolar binary mixture of hard spheres and square-well spheres are allowed to react to form a dimer. As the bond length shrinks to zero, we create a site-site model of a Janus-like molecule with a repulsive moiety and an attractive moiety. We employ the zero-separation (ZSEP) closure to solve the OZ equations. The structure and thermodynamic properties are calculated at three isotherms and at several densities and the results are compared with Monte Carlo simulations. The close agreement achieved demonstrates that the ZSEP closure is a reliable theory for this composite-sphere fluid model. Contribution to the George Stell Memorial Issue.

  17. Base Isolation for Seismic Retrofitting of a Multiple Building Structure: Design, Construction, and Assessment

    Directory of Open Access Journals (Sweden)

    Massimiliano Ferraioli

    2017-01-01

    Full Text Available The paper deals with the seismic retrofit of a multiple building structure belonging to the Hospital Centre of Avellino (Italy. At first, the paper presents the preliminary investigations, the in situ measurements and laboratory tests, and the seismic assessment of the existing fixed-base structures. Having studied different strategies, base isolation proved to be the more appropriate, also for the possibility offered by the geometry of the building to easily create an isolation interface at the ground level. The paper presents the design project, the construction process, and the details of the isolation intervention. Some specific issues of base isolation for seismic retrofitting of multiple building structures were lightened. Finally, the seismic assessment of the base-isolated building was carried out. The seismic response was evaluated through nonlinear time-history analysis, using the well-known Bouc-Wen model as the constitutive law of the isolation bearings. For reliable dynamic analyses, a suite of natural accelerograms compatible with acceleration spectra of Italian Code was first selected and then applied along both horizontal directions. The results were finally used to address some of the critical issues of the seismic response of the base-isolated multiple building structure: accidental torsional effects and potential poundings during strong earthquakes.

  18. Atomic structure and handedness of the building block of a biological assembly.

    Science.gov (United States)

    Loquet, Antoine; Habenstein, Birgit; Chevelkov, Veniamin; Vasa, Suresh Kumar; Giller, Karin; Becker, Stefan; Lange, Adam

    2013-12-26

    Noncovalent supramolecular assemblies possess in general several unique subunit-subunit interfaces.The basic building block of such an assembly consists of several subunits and contains all unique interfaces. Atomic-resolution structures of monomeric subunits are typically accessed by crystallography or solution NMR and fitted into electron microscopy density maps. However, the structure of the intact building block in the assembled state remains unknown with this hybrid approach. Here, we present the solid-state NMR atomic structure of the building block of the type III secretion system needle. The building block structure consists of a homotetrameric subunit complex with three unique supramolecular interfaces. Side-chain positions at the interfaces were solved at atomic detail. The high-resolution structure reveals unambiguously the helical handedness of the assembly, determined to be right-handed for the type III secretion system needle.Additionally, the axial rise per subunit could be extracted from the tetramer structure and independently validated by mass-per-length measurements.

  19. Structural equation modeling: building and evaluating causal models: Chapter 8

    Science.gov (United States)

    Grace, James B.; Scheiner, Samuel M.; Schoolmaster, Donald R.

    2015-01-01

    Scientists frequently wish to study hypotheses about causal relationships, rather than just statistical associations. This chapter addresses the question of how scientists might approach this ambitious task. Here we describe structural equation modeling (SEM), a general modeling framework for the study of causal hypotheses. Our goals are to (a) concisely describe the methodology, (b) illustrate its utility for investigating ecological systems, and (c) provide guidance for its application. Throughout our presentation, we rely on a study of the effects of human activities on wetland ecosystems to make our description of methodology more tangible. We begin by presenting the fundamental principles of SEM, including both its distinguishing characteristics and the requirements for modeling hypotheses about causal networks. We then illustrate SEM procedures and offer guidelines for conducting SEM analyses. Our focus in this presentation is on basic modeling objectives and core techniques. Pointers to additional modeling options are also given.

  20. Building classroom and organizational structure around positive cultural values

    Science.gov (United States)

    Albanna, Badr F.; Corbo, Joel C.; Dounas-Frazer, Dimitri R.; Little, Angela; Zaniewski, Anna M.

    2013-01-01

    The Compass Project is a self-formed group of graduate and undergraduate students in the physical sciences at UC Berkeley. Our goals are to improve undergraduate physics education, provide opportunities for professional development, and increase retention of students-especially those from populations typically underrepresented in the physical sciences. Compass fosters a diverse, collaborative student community by providing a wide range of services, including a summer program and fall/spring seminar courses. We describe Compass's cultural values, discuss how community members are introduced to and help shape those values, and demonstrate how a single set of values informs the structure of both our classroom and organization. We emphasize that all members of the Compass community participate in, and benefit from, our cultural values, regardless of status as student, teacher, or otherwise.

  1. Building Classroom and Organizational Structure Around Positive Cultural Values

    CERN Document Server

    Albanna, Badr F; Dounas-Frazer, Dimitri R; Little, Angela; Zaniewski, Anna M

    2012-01-01

    The Compass Project is a self-formed group of graduate and undergraduate students in the physical sciences at UC Berkeley. Our goals are to improve undergraduate physics education, provide opportunities for professional development, and increase retention of students-especially those from populations typically underrepresented in the physical sciences. Compass fosters a diverse, collaborative student community by providing a wide range of services, including a summer program and fall/spring seminar courses. We describe Compass's cultural values, discuss how community members are introduced to and help shape those values, and demonstrate how a single set of values informs the structure of both our classroom and organization.We emphasize that all members of the Compass community participate in, and benefit from, our cultural values, regardless of status as student, teacher, or otherwise.

  2. Building Medium Size Telescope Structures for the Cherenkov Telescope Array

    CERN Document Server

    Schulz, A; Oakes, L; Schlenstedt, S; Schwanke, U

    2016-01-01

    The Cherenkov Telescope Array (CTA) is the future instrument in ground-based gamma-ray astronomy in the energy range from 20 GeV to 300 TeV. Its sensitivity will surpass that of current generation experiments by a factor $\\sim$10, facilitated by telescopes of three sizes. The performance in the core energy regime will be dominated by Medium Size Telescopes (MST) with a reflector of 12 m diameter. A full-size mechanical prototype of the telescope structure has been constructed in Berlin. The performance of the prototype is being evaluated and optimisations, among others, facilitating the assembly procedure and mass production possibilities are being implemented. We present the current status of the developments from prototyping towards pre-production telescopes, which will be deployed at the final site.

  3. Prediction of Noise Transmission in Lightweight Building Structures

    DEFF Research Database (Denmark)

    Dickow, Kristoffer Ahrens

    groups, where one group shows pass band/stop band behavior, while the other has a nearly uniform distribution of modes. The suggested approach for SEA adaptation is to consider a ribbed plate as two SEA subsystems: One that contains modes related to waves traveling in the direction orthogonal to the ribs......, while the other subsystem contains modes related to waves traveling parallel to the rib stiffeners. The investigations utilize Monte Carlo simulations to examine the behavior of nominally identical plates. Next, two papers that utilize the Finite-Element Method, focusing on aspects of modeling ribbed...... full three-dimensional, solid continuum finite-elements. When using structural elements such as beams and shells, couplings may be modeled as either line or point coupling. However, when utilizing full three-dimensional, solid finite-elements, the scenario is not that simple. The investigations of both...

  4. Effect of nonlinearity of connecting dampers on vibration control of connected building structures

    Directory of Open Access Journals (Sweden)

    Masatoshi eKasagi

    2016-01-01

    Full Text Available The connection of two building structures with dampers is one of effective vibration control systems. In this vibration control system, both buildings have to possess different vibration properties in order to provide a higher vibration reduction performance. In addition to such condition of different vibration properties of both buildings, the connecting dampers also play an important role in the vibration control mechanism. In this paper, the effect of nonlinearity of connecting dampers on the vibration control of connected building structures is investigated in detail. A high-damping rubber damper and an oil damper with and without relief mechanism are treated. It is shown that, while the high-damping rubber damper is effective in a rather small deformation level, the linear oil damper is effective in a relatively large deformation level. It is further shown that, while the oil dampers reduce the response in the same phase as the case without dampers, the high-damping rubber dampers change the phase. The merit is that the high-damping rubber can reduce the damper deformation and keep the sufficient space between both buildings. This can mitigate the risk of building pounding.

  5. METHOD AND DEVICE FOR REMOVING AN IONIC IMPURITY FROM BUILDING STRUCTURES

    DEFF Research Database (Denmark)

    2009-01-01

    The invention relates to a method for removing an ionic impurity from building structures comprising the steps of: forming at least one electrode unit (2, 3) by mixing a clay compound with an ion exchange component; placing at least one anode (4) and at least one cathode (5) at the same or separate......). The invention further relates to a device for removing an ionic impurity from building structures, the device including electrode units (2, 3) consisting of at least one electrode being an anode) (4) or a cathode (5) and at least one buffer component arranged in a poultice (8) including an ion exchange...

  6. Economic Feasibility Analysis of the Application of Geothermal Energy Facilities to Public Building Structures

    Directory of Open Access Journals (Sweden)

    Sangyong Kim

    2014-03-01

    Full Text Available This study aims to present an efficient plan for the application of a geothermal energy facility at the building structure planning phase. Energy consumption, energy cost and the primary energy consumption of buildings were calculated to enable a comparison of buildings prior to the application of a geothermal energy facility. The capacity for energy savings and the costs related to the installation of such a facility were estimated. To obtain more reliable criteria for economic feasibility, the lifecycle cost (LCC analysis incorporated maintenance costs (reflecting repair and replacement cycles based on construction work specifications of a new renewable energy facility and initial construction costs (calculated based on design drawings for its practical installation. It is expected that the findings of this study will help in the selection of an economically viable geothermal energy facility at the building construction planning phase.

  7. Behaviour of AR glass fibre for building structural applications

    Directory of Open Access Journals (Sweden)

    Miravete, A.

    2005-12-01

    Full Text Available The AR glass reinforcement fibres were designed to resist the alkalis from the concrete. This is the main reason for its utilisation as a short-fibre-reinforcement of mortar and concrete for the last decades. Originally, the AR glass fibre sizing was not compatible with synthetic resins, so that this type of reinforcement was applied exclusively to mortar and concrete matrices. Recently, due to the developments of sizing, which are compatible with synthetic resins, the AR- glass fibres may be used as reinforcement of organic matrix composite materials, broadening the range of structural applications. The mechanical properties of AR glass fibre and organic matrix composite materials will be studied in this paper. First, the behaviour of this material under stress corrosion will be analysed. Their mass loss will be compared to E, C, and boron free glass fibres. Second, an experimental study dealing with 3P test bending and short beam ofAR glass fibre/polyester will de described with the goal of obtaining their Young modulus and tensile and interlaminar shear strengths. Finally, these experimental results will be compared to E glass fibre/polyester and several conclusions about their structural applications will be drawn.

    El vidrio AR y su presentación en forma de fibras de refuerzo, fue diseñado para ser inerte a los álcalis de los cementos. Por este motivo se viene utilizando desde hace varias décadas como refuerzo de morteros y hormigones en forma de fibra corta. El ensimaje que estas fibras de vidrio de refuerzo A R presentaba en su origen no era compatible con resinas de tipo sintéticas, por lo que el refuerzo era exclusivo para cementos y hormigones fuera cual fuera la aplicación, formato o proceso productivo. Recientemente, gracias al desarrollo específico de ensimajes especiales acordes a las fibras de vidrio AR ha aparecido la misma tipología de vidrio AR como refuerzo en forma de fibra continua compatible con resinas sint

  8. Building Structural Complexity in Semiconductor Nanocrystals through Chemical Transformations

    Energy Technology Data Exchange (ETDEWEB)

    Sadtler, Bryce F [Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2009-05-01

    Ag2S lattices were used to calculate interface formation energies. The formation energies indicate the favorability for interface nucleation at different facets of the nanorod and the stability of the interfaces during growth of the secondary material (Cu2S or Ag2S) within the CdS nanocrystal. The physical properties of the CdS-Ag2S and CdS-Cu2S binary nanorods are discussed in terms of the electronic structure of their components and the heterostructure morphology.

  9. Lipid-insertion enables targeting functionalization of erythrocyte membrane-cloaked nanoparticles

    Science.gov (United States)

    Fang, Ronnie H.; Hu, Che-Ming J.; Chen, Kevin N. H.; Luk, Brian T.; Carpenter, Cody W.; Gao, Weiwei; Li, Shulin; Zhang, Dong-Er; Lu, Weiyue; Zhang, Liangfang

    2013-09-01

    RBC membrane-cloaked polymeric nanoparticles represent an emerging nanocarrier platform with extended circulation in vivo. A lipid-insertion method is employed to functionalize these nanoparticles without the need for direct chemical conjugation. Insertion of both folate and the nucleolin-targeting aptamer AS1411 shows receptor-specific targeting against model cancer cell lines.RBC membrane-cloaked polymeric nanoparticles represent an emerging nanocarrier platform with extended circulation in vivo. A lipid-insertion method is employed to functionalize these nanoparticles without the need for direct chemical conjugation. Insertion of both folate and the nucleolin-targeting aptamer AS1411 shows receptor-specific targeting against model cancer cell lines. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr03064d

  10. Invisibility cloak inside a Luneburg lens: Experimental demonstration of birefrigent transformation optics devices

    CERN Document Server

    Smolyaninova, V N; Piazza, A; Schaefer, D; Smolyaninov, I I

    2012-01-01

    Transformation optics (TO) has recently become a useful methodology in the design of unusual optical devices, such as novel metamaterial lenses and invisibility cloaks. Very recently Danner et al. [1] have suggested theoretical extension of this approach to birefrigent TO devices, which perform useful and different functions for mutually orthogonal polarization states of light. Theoretical designs which operate as invisibility cloak for one polarization while behaving as a Luneburg lens for another orthogonal polarization have been suggested. Here we report the first experimental realization of this and other birefrigent TO designs based on lithographically defined metal/dielectric waveguides. Adiabatic variations of the waveguide shape enable control of the effective refractive indices experienced by the TE and TM modes propagating inside the waveguides. We have studied wavelength and polarization dependent performance of the resulting birefrigent TO devices. These novel optical devices considerably extend o...

  11. Total reflection and cloaking by zero index metamaterials loaded with rectangular dielectric defects

    KAUST Repository

    Wu, Ying

    2013-05-06

    In this work, we investigate wave transmission property through a zero index metamaterial (ZIM) waveguide embedded with rectangular dielectric defects. We show that total reflection and total transmission (cloaking) can be achieved by adjusting the geometric sizes and/or permittivities of the defects. Our work provides another possibility of manipulating wave propagation through ZIM in addition to the widely studied dielectric defects with cylindrical geometries.

  12. Optic-null space medium for cover-up cloaking without any negative refraction index materials

    OpenAIRE

    Fei Sun; Sailing He

    2016-01-01

    With the help of optic-null medium, we propose a new way to achieve invisibility by covering up the scattering without using any negative refraction index materials. Compared with previous methods to achieve invisibility, the function of our cloak is to cover up the scattering of the objects to be concealed by a background object of strong scattering. The concealed object can receive information from the outside world without being detected. Numerical simulations verify the performance of our...

  13. Increasing the density of passive photonic-integrated circuits via nanophotonic cloaking

    Science.gov (United States)

    Shen, Bing; Polson, Randy; Menon, Rajesh

    2016-11-01

    Photonic-integrated devices need to be adequately spaced apart to prevent signal cross-talk. This fundamentally limits their packing density. Here we report the use of nanophotonic cloaking to render neighbouring devices invisible to one another, which allows them to be placed closer together than is otherwise feasible. Specifically, we experimentally demonstrated waveguides that are spaced by a distance of ~λ0/2 and designed waveguides with centre-to-centre spacing as small as 600 nm (experiments show a transmission efficiency >-2 dB and an extinction ratio >15 dB over a bandwidth larger than 60 nm. This performance can be improved with better design algorithms and industry-standard lithography. The nanophotonic cloak relies on multiple guided-mode resonances, which render such devices very robust to fabrication errors. Our devices are broadly complimentary-metal-oxide-semiconductor compatible, have a minimum pitch of 200 nm and can be fabricated with a single lithography step. The nanophotonic cloaks can be generally applied to all passive integrated photonics.

  14. Dispersion engineering of metasurfaces for dual-frequency quasi-three-dimensional cloaking of microwave radiators.

    Science.gov (United States)

    Jiang, Zhi Hao; Werner, Douglas H

    2016-05-01

    In this work, the design methodology and experimental investigation of compact and lightweight dispersive coatings, comprised by multiple layers of anisotropic metasurfaces, which are capable of cloaking radiators at multiple frequencies are presented. To determine the required surface electromagnetic properties for each layer, an analytical model is developed for predicting the scattering from a cylinder surrounded by multiple layers of anisotropic metasurfaces subject to plane-wave illumination at a general oblique incidence angle. Particularly, two different metasurface coating solutions with different dispersive properties are designed to provide more than 10 dB scattering width suppression at two pre-selected frequencies within a field-of-view (FOV) of ± 20° off normal incidence. Both coating designs implemented using metasurfaces are fabricated and measured, experimentally demonstrating the simultaneous suppression of mutual coupling and quasi-three-dimensional radiation blockage at the two pre-selected frequency ranges. At the same time, the functionality of the coated monopole is still well-maintained. The performance comparison further sheds light on how the optimal performance can be obtained by properly exploiting the dispersion of each metasurface layer of the coating. In addition, the cloaking effect is retained even when the distance between the radiators is significantly reduced. The concept and general design methodology presented here can be extended for applications that would benefit from cloaking multi-spectral terahertz as well as optical antennas.

  15. Optimal design of snow avalanche passive defence structure using reliability approach to quantify buildings vulnerability

    Science.gov (United States)

    Favier, P.; Bertrand, D.; Eckert, N.; Naaim, M.

    2012-04-01

    To protect elements at risk (humans, roads, houses, etc.) against snow avalanches, civil engineering structures, such as dams or mounds, are used. The design of such defence structures is done following a deterministic approach which considers European regulation. The minimization of expected total losses is an interesting alternative that generalizes cost-benefit approach to a continuous decision variable. For this purpose, not only the hazard magnitude but also the buildings vulnerability must be evaluated carefully. The aim of this work is therefore to combine state of the art sub-models for the probabilistic description of avalanche flows and the numerical evaluation of damages to buildings. We defined the risk as the expectation of the cost consequences of avalanches activity. Disposal consequences are quantified thanks to reliability methods. In this formulation, the accuracy of both the hazard estimation and the vulnerability calculation has to be consistent according to precision and computational costs. To do so, a numerical approach has been developed to evaluate the physical vulnerability of concrete buildings submitted to avalanche loadings. The ensuing application illustrates our approach. A reinforced concrete slab is considered to model the building with a finite element method. Reliability approach enables to produce a response spectrum of the structure against avalanche impact. Finally, vulnerability curves are built. Outcomes of the risk calculation are examined to find sensitivity on the optimal design of snow defence structures.

  16. POLYMER AND CEMENT MORTARS FOR THE CONSTRUCTION AND REPAIR OF BUILDINGS AND STRUCTURE

    Directory of Open Access Journals (Sweden)

    O. M. Pshinko

    2009-02-01

    Full Text Available In the article the analysis of polymer-cement mortars for their application in construction and repair of buildings and structures is presented. The main properties of known polymer-cement mortars used for this purpose are described. The advantages of application of polymer-cement mortars as repair materials are shown.

  17. PCM-enhanced building components an application of phase change materials in building envelopes and internal structures

    CERN Document Server

    Kosny, Jan

    2015-01-01

    Presenting an overview of the use of Phase Change Materials (PCMs) within buildings, this book discusses the performance of PCM-enhanced building envelopes. It reviews the most common PCMs suitable for building applications, and discusses PCM encapsulation and packaging methods. In addition to this, it examines a range of PCM-enhanced building products in the process of development as well as examples of whole-building-scale field demonstrations. Further chapters discuss experimental and theoretical analyses (including available software) to determine dynamic thermal and energy performance ch

  18. 3D building reconstruction from ALS data using unambiguous decomposition into elementary structures

    Science.gov (United States)

    Jarząbek-Rychard, M.; Borkowski, A.

    2016-08-01

    The objective of the paper is to develop an automated method that enables for the recognition and semantic interpretation of topological building structures. The novelty of the proposed modeling approach is an unambiguous decomposition of complex objects into predefined simple parametric structures, resulting in the reconstruction of one topological unit without independent overlapping elements. The aim of a data processing chain is to generate complete polyhedral models at LOD2 with an explicit topological structure and semantic information. The algorithms are performed on 3D point clouds acquired by airborne laser scanning. The presented methodology combines data-based information reflected in an attributed roof topology graph with common knowledge about buildings stored in a library of elementary structures. In order to achieve an appropriate balance between reconstruction precision and visualization aspects, the implemented library contains a set of structure-depended soft modeling rules instead of strictly defined geometric primitives. The proposed modeling algorithm starts with roof plane extraction performed by the segmentation of building point clouds, followed by topology identification and recognition of predefined structures. We evaluate the performance of the novel procedure by the analysis of the modeling accuracy and the degree of modeling detail. The assessment according to the validation methods standardized by the International Society for Photogrammetry and Remote Sensing shows that the completeness of the algorithm is above 80%, whereas the correctness exceeds 98%.

  19. On the use of tensegrity structures for kinetic solar facades of smart buildings

    Science.gov (United States)

    Fraternali, F.; De Chiara, E.; Skelton, R. E.

    2015-10-01

    We investigate the use of tensegrity structures with morphing and prestress-stability capabilities for the design of active solar façades of smart buildings. Morphing tensegrity lattices are used to design shading screens composed of umbrella-shaped ‘eyes’ that are opened and closed by adjusting the elongation in a limited number of cables. Prestressable lattices are instead employed to design superstable Venetian blinds that are composed of orientable slats. Future use of tensegrity solutions for next-generation smart buildings are outlined, with the aim of designing kinetic solar façades that combine morphing abilities with prestress-stability.

  20. Seismic response of tall building considering soil-pile-structure interaction

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The seismic behavior of tall buildings can be greatly affected by non-linear soil-pile interaction during strongearthquakes. In this study a 20-storey building is examined as a typical structure supported on a pile foundation for differentconditions: (1) rigid base, i.e. no deformation in the foundation: (2) linear soil-pile system; and (3) nonlinear soil-pile system.The effects of pile foundation displacements on the behavior of tall building are investigated, and compared with the behavior ofbuildings supported on shallow foundation. With a model of non-reflective boundary between the near field and far field,Novak's method of soil-pile interaction is improved. The computation method for vibration of pile foundations and DYNANcomputer program are introduced comprehensively. A series of dynamic experiments have been done on full-scale piles,including single pile and group, linear vibration and nonlinear vibration, to verify the validity of boundary zone model.

  1. Life Comparative Analysis of Energy Consumption and CO2 Emissions of Different Building Structural Frame Types

    Directory of Open Access Journals (Sweden)

    Sangyong Kim

    2013-01-01

    Full Text Available The objective of this research is to quantitatively measure and compare the environmental load and construction cost of different structural frame types. Construction cost also accounts for the costs of CO2 emissions of input materials. The choice of structural frame type is a major consideration in construction, as this element represents about 33% of total building construction costs. In this research, four constructed buildings were analyzed, with these having either reinforced concrete (RC or steel (S structures. An input-output framework analysis was used to measure energy consumption and CO2 emissions of input materials for each structural frame type. In addition, the CO2 emissions cost was measured using the trading price of CO2 emissions on the International Commodity Exchange. This research revealed that both energy consumption and CO2 emissions were, on average, 26% lower with the RC structure than with the S structure, and the construction costs (including the CO2 emissions cost of the RC structure were about 9.8% lower, compared to the S structure. This research provides insights through which the construction industry will be able to respond to the carbon market, which is expected to continue to grow in the future.

  2. Life comparative analysis of energy consumption and CO₂ emissions of different building structural frame types.

    Science.gov (United States)

    Kim, Sangyong; Moon, Joon-Ho; Shin, Yoonseok; Kim, Gwang-Hee; Seo, Deok-Seok

    2013-01-01

    The objective of this research is to quantitatively measure and compare the environmental load and construction cost of different structural frame types. Construction cost also accounts for the costs of CO₂ emissions of input materials. The choice of structural frame type is a major consideration in construction, as this element represents about 33% of total building construction costs. In this research, four constructed buildings were analyzed, with these having either reinforced concrete (RC) or steel (S) structures. An input-output framework analysis was used to measure energy consumption and CO₂ emissions of input materials for each structural frame type. In addition, the CO₂ emissions cost was measured using the trading price of CO₂ emissions on the International Commodity Exchange. This research revealed that both energy consumption and CO₂ emissions were, on average, 26% lower with the RC structure than with the S structure, and the construction costs (including the CO₂ emissions cost) of the RC structure were about 9.8% lower, compared to the S structure. This research provides insights through which the construction industry will be able to respond to the carbon market, which is expected to continue to grow in the future.

  3. Routing Corners of Building Structures - by the Method of Vector Addition - Measured with RTN GNSS Surveying Technology

    Science.gov (United States)

    Krzyżek, Robert

    2015-12-01

    The paper deals with the problem of surveying buildings in the RTN GNSS mode using modernized indirect methods of measurement. As a result of the classical realtime measurements using indirect methods (intersection of straight lines or a point on a straight line), we obtain a building structure (a building) which is largely deformed. This distortion is due to the inconsistency of the actual dimensions of the building (tie distances) relative to the obtained measurement results. In order to eliminate these discrepancies, and thus to ensure full consistency of the building geometric structure, an innovative solution was applied - the method of vector addition - to modify the linear values (tie distances) of the external face of the building walls. A separate research problem tackled in the article, although not yet fully solved, is the issue of coordinates of corners of a building obtained after the application of the method of vector addition.

  4. Analysis, Design, and Construction of a Base-Isolated Multiple Building Structure

    Directory of Open Access Journals (Sweden)

    Stefano Sorace

    2014-01-01

    Full Text Available The analysis and design of a multiple residential building, seismically protected by a base isolation system incorporating double friction pendulum sliders as protective devices, are presented in the paper. The building, situated in the suburban area of Florence, is composed of four independent reinforced concrete framed structures, mutually separated by three thermal expansion joints. The plan is L-shaped, with dimensions of about 75 m in the longitudinal direction and about 30 m along the longest side of the transversal direction. These characteristics identify the structure as the largest example of a base-isolated “artificial ground” ever built in Italy. The base isolation solution guarantees lower costs, a much greater performance, and a finer architectural look, as compared to a conventional fixed-base antiseismic design. The characteristics of the building and the isolators, the mechanical properties and the experimental characterization campaign and preliminary sizing carried out on the latter, and the nonlinear time-history design and performance assessment analyses developed on the base isolated building are reported in this paper, along with details about the installation of the isolators and the plants and highlights of the construction works.

  5. Preliminary Dynamic Siol-Structure-Interaction Analysis for the Waste Handling Building

    Energy Technology Data Exchange (ETDEWEB)

    G. Wagenblast

    2000-05-01

    The objective of this analysis package is to document a preliminary dynamic seismic evaluation of a simplified design concept of the Wade Handling Building (WHB). Preliminary seismic ground motions and soil data will be used. Loading criteria of the WHB System Design Description will be used. Detail design of structural members will not be performed.. The results of the analysis will be used to determine preliminary sizes of structural concrete and steel members and to determine whether the seismic response of the structure is within an acceptable level for future License Application design of safety related facilities. In order to complete this preliminary dynamic evaluation to meet the Site Recommendation (SR) schedule, the building configuration was ''frozen in time'' as the conceptual design existed in October 1999. Modular design features and dry or wet waste storage features were intentionally excluded from this preliminary dynamic seismic evaluation. The document was prepared in accordance with the Development Plan for the ''Preliminary/Dynamic Soil Structure Interaction Analysis for the Waste Handling Building'' (CRWMS M&O 2000b), which was completed, in accordance with AP-2.13Q, ''Technical Product Development Planning''.

  6. Automated metric characterization of urban structure using building decomposition from very high resolution imagery

    Science.gov (United States)

    Heinzel, Johannes; Kemper, Thomas

    2015-03-01

    Classification approaches for urban areas are mostly of qualitative and semantic nature. They produce interpreted classes similar to those from land cover and land use classifications. As a complement to those classes, quantitative measures directly derived from the image could lead to a metric characterization of the urban area. While these metrics lack of qualitative interpretation they are able to provide objective measure of the urban structures. Such quantitative measures are especially important in rapidly growing cities since, beside of the growth in area, they can provide structural information for specific areas and detect changes. Rustenburg, which serves as test area for the present study, is amongst the fastest growing cities in South Africa. It reveals a heterogeneous face of housing and building structures reflecting social and/or economic differences often linked to the spatial distribution of industrial and local mining sites. Up to date coverage with aerial photographs is provided by aerial surveys in regular intervals. Also recent satellite systems provide imagery with suitable resolution. Using such set of very high resolution images a fully automated algorithm has been developed which outputs metric classes by systematically combining important measures of building structure. The measurements are gained by decomposition of buildings directly from the imagery and by using methods from mathematical morphology. The decomposed building objects serve as basis for the computation of grid statistics. Finally a systematic combination of the single features leads to combined metrical classes. For the dominant urban structures verification results indicate an overall accuracy of at least 80% on the single feature level and 70% for the combined classes.

  7. Utilization of the Building-Block Approach in Structural Mechanics Research

    Science.gov (United States)

    Rouse, Marshall; Jegley, Dawn C.; McGowan, David M.; Bush, Harold G.; Waters, W. Allen

    2005-01-01

    In the last 20 years NASA has worked in collaboration with industry to develop enabling technologies needed to make aircraft safer and more affordable, extend their lifetime, improve their reliability, better understand their behavior, and reduce their weight. To support these efforts, research programs starting with ideas and culminating in full-scale structural testing were conducted at the NASA Langley Research Center. Each program contained development efforts that (a) started with selecting the material system and manufacturing approach; (b) moved on to experimentation and analysis of small samples to characterize the system and quantify behavior in the presence of defects like damage and imperfections; (c) progressed on to examining larger structures to examine buckling behavior, combined loadings, and built-up structures; and (d) finally moved to complicated subcomponents and full-scale components. Each step along the way was supported by detailed analysis, including tool development, to prove that the behavior of these structures was well-understood and predictable. This approach for developing technology became known as the "building-block" approach. In the Advanced Composites Technology Program and the High Speed Research Program the building-block approach was used to develop a true understanding of the response of the structures involved through experimentation and analysis. The philosophy that if the structural response couldn't be accurately predicted, it wasn't really understood, was critical to the progression of these programs. To this end, analytical techniques including closed-form and finite elements were employed and experimentation used to verify assumptions at each step along the way. This paper presents a discussion of the utilization of the building-block approach described previously in structural mechanics research and development programs at NASA Langley Research Center. Specific examples that illustrate the use of this approach are

  8. Aircraft-crash-protected steel reactor building roof structure for the European market

    Energy Technology Data Exchange (ETDEWEB)

    Posta, B.A.; Kadar, I. [Bechtel Corp., San Francisco, CA (United States); Rao, A.S. [General Electric Nuclear Engineering, San Jose, CA (United States)

    1996-07-01

    This paper recommends the use of all steel roof structures for the reactor building of European Boiling Water Reactor (BWR) plants. This change would make the advanced US BWR designs more compatible with European requirements. Replacement of the existing concrete roof slab with a sufficiently thick steel plate would eliminate the concrete spelling resulting from a postulated aircraft crash, potentially damaging the drywell head or the spent fuel pool.

  9. Teaching optimization of students at design of buildings and structures foundations

    OpenAIRE

    Misura, Lid. V.; MISURA Liub. V.; Poltorachenko, N. I.

    2016-01-01

    Raising of problem. According to world statistics, more than 75 % of all violations of the normal operation of buildings and structures is due to deficiencies in the design, construction and operation of bases and foundations [1]. The costs to eliminate these negative effects can be compared only with the initial cost of construction, it speaks about the relevance of teaching subjects related to the design of foundations. On the other hand increased demands on the students' knowledge, raises ...

  10. Deer herbivory reduces web-building spider abundance by simplifying forest vegetation structure

    Science.gov (United States)

    Chips, Michael J.; Carson, Walter P.

    2016-01-01

    Indirect ecological effects are a common feature of ecological systems, arising when one species affects interactions among two or more other species. We examined how browsing by white-tailed deer (Odocoileus virginianus) indirectly affected the abundance and composition of a web-building spider guild through their effects on the structure of the ground and shrub layers of northern hardwood forests. We examined paired plots consisting of deer-free and control plots in the Allegheny Plateau region Pennsylvania and Northern Highlands region of Wisconsin. We recorded the abundance of seven types of webs, each corresponding to a family of web-building spiders. We quantified vegetation structure and habitat suitability for the spiders by computing a web scaffold availability index (WSAI) at 0.5 m and 1.0 m above the ground. At Northern Highlands sites, we recorded prey availability. Spider webs were twice as abundant in deer-free plots compared to control plots, while WSAI was 7–12 times greater in deerfree plots. Prey availability was lower in deer-free plots. With the exception of funnel web-builders, all spider web types were significantly more abundant in deer-free plots. Both deer exclusion and the geographic region of plots were significant predictors of spider community structure. In closed canopy forests with high browsing pressure, the low density of tree saplings and shrubs provides few locations for web-building spiders to anchor webs. Recruitment of these spiders may become coupled with forest disturbance events that increase tree and shrub recruitment. By modifying habitat structure, deer appear to indirectly modify arthropod food web interactions. As deer populations have increased in eastern North America over the past several decades, the effects of deer on web-building spiders may be widespread. PMID:27703868

  11. Deer herbivory reduces web-building spider abundance by simplifying forest vegetation structure.

    Science.gov (United States)

    Roberson, Elizabeth J; Chips, Michael J; Carson, Walter P; Rooney, Thomas P

    2016-01-01

    Indirect ecological effects are a common feature of ecological systems, arising when one species affects interactions among two or more other species. We examined how browsing by white-tailed deer (Odocoileus virginianus) indirectly affected the abundance and composition of a web-building spider guild through their effects on the structure of the ground and shrub layers of northern hardwood forests. We examined paired plots consisting of deer-free and control plots in the Allegheny Plateau region Pennsylvania and Northern Highlands region of Wisconsin. We recorded the abundance of seven types of webs, each corresponding to a family of web-building spiders. We quantified vegetation structure and habitat suitability for the spiders by computing a web scaffold availability index (WSAI) at 0.5 m and 1.0 m above the ground. At Northern Highlands sites, we recorded prey availability. Spider webs were twice as abundant in deer-free plots compared to control plots, while WSAI was 7-12 times greater in deerfree plots. Prey availability was lower in deer-free plots. With the exception of funnel web-builders, all spider web types were significantly more abundant in deer-free plots. Both deer exclusion and the geographic region of plots were significant predictors of spider community structure. In closed canopy forests with high browsing pressure, the low density of tree saplings and shrubs provides few locations for web-building spiders to anchor webs. Recruitment of these spiders may become coupled with forest disturbance events that increase tree and shrub recruitment. By modifying habitat structure, deer appear to indirectly modify arthropod food web interactions. As deer populations have increased in eastern North America over the past several decades, the effects of deer on web-building spiders may be widespread.

  12. Deer herbivory reduces web-building spider abundance by simplifying forest vegetation structure

    Directory of Open Access Journals (Sweden)

    Elizabeth J. Roberson

    2016-09-01

    Full Text Available Indirect ecological effects are a common feature of ecological systems, arising when one species affects interactions among two or more other species. We examined how browsing by white-tailed deer (Odocoileus virginianus indirectly affected the abundance and composition of a web-building spider guild through their effects on the structure of the ground and shrub layers of northern hardwood forests. We examined paired plots consisting of deer-free and control plots in the Allegheny Plateau region Pennsylvania and Northern Highlands region of Wisconsin. We recorded the abundance of seven types of webs, each corresponding to a family of web-building spiders. We quantified vegetation structure and habitat suitability for the spiders by computing a web scaffold availability index (WSAI at 0.5 m and 1.0 m above the ground. At Northern Highlands sites, we recorded prey availability. Spider webs were twice as abundant in deer-free plots compared to control plots, while WSAI was 7–12 times greater in deerfree plots. Prey availability was lower in deer-free plots. With the exception of funnel web-builders, all spider web types were significantly more abundant in deer-free plots. Both deer exclusion and the geographic region of plots were significant predictors of spider community structure. In closed canopy forests with high browsing pressure, the low density of tree saplings and shrubs provides few locations for web-building spiders to anchor webs. Recruitment of these spiders may become coupled with forest disturbance events that increase tree and shrub recruitment. By modifying habitat structure, deer appear to indirectly modify arthropod food web interactions. As deer populations have increased in eastern North America over the past several decades, the effects of deer on web-building spiders may be widespread.

  13. Deer herbivory reduces web-building spider abundance by simplifying forest vegetation structure

    OpenAIRE

    Roberson, Elizabeth J.; Chips, Michael J.; Walter P. Carson; Thomas P. Rooney

    2016-01-01

    Indirect ecological effects are a common feature of ecological systems, arising when one species affects interactions among two or more other species. We examined how browsing by white-tailed deer (Odocoileus virginianus) indirectly affected the abundance and composition of a web-building spider guild through their effects on the structure of the ground and shrub layers of northern hardwood forests. We examined paired plots consisting of deer-free and control plots in the Allegheny Plateau re...

  14. Building Large Collections of Chinese and English Medical Terms from Semi-Structured and Encyclopedia Websites

    OpenAIRE

    Yan Xu; Yining Wang; Jian-Tao Sun; Jianwen Zhang; Junichi Tsujii; Eric Chang

    2013-01-01

    To build large collections of medical terms from semi-structured information sources (e.g. tables, lists, etc.) and encyclopedia sites on the web. The terms are classified into the three semantic categories, Medical Problems, Medications, and Medical Tests, which were used in i2b2 challenge tasks. We developed two systems, one for Chinese and another for English terms. The two systems share the same methodology and use the same software with minimum language dependent parts. We produced large...

  15. An integrated approach to structural design of buildings using genetic algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Rafiq, M.Y.; Mathews, J.D. [Univ. of Plymouth (United Kingdom)

    1996-12-31

    This paper presents an evolutionary approach to the integration of design activities, in the area of structural design of buildings, using Genetic Algorithms (GA). Integration process is viewed in two contexts: (i) Integration across the design activities within a particular discipline, and (ii) Integration across of the disciplines involved in the design. Particular advantages of the integration of design activities during the conceptual stage of the design process are highlighted.

  16. Automated Building Extraction from High-Resolution Satellite Imagery in Urban Areas Using Structural, Contextual, and Spectral Information

    Directory of Open Access Journals (Sweden)

    Curt H. Davis

    2005-08-01

    Full Text Available High-resolution satellite imagery provides an important new data source for building extraction. We demonstrate an integrated strategy for identifying buildings in 1-meter resolution satellite imagery of urban areas. Buildings are extracted using structural, contextual, and spectral information. First, a series of geodesic opening and closing operations are used to build a differential morphological profile (DMP that provides image structural information. Building hypotheses are generated and verified through shape analysis applied to the DMP. Second, shadows are extracted using the DMP to provide reliable contextual information to hypothesize position and size of adjacent buildings. Seed building rectangles are verified and grown on a finely segmented image. Next, bright buildings are extracted using spectral information. The extraction results from the different information sources are combined after independent extraction. Performance evaluation of the building extraction on an urban test site using IKONOS satellite imagery of the City of Columbia, Missouri, is reported. With the combination of structural, contextual, and spectral information, 72.7% of the building areas are extracted with a quality percentage 58.8%.

  17. Vision-based system identification technique for building structures using a motion capture system

    Science.gov (United States)

    Oh, Byung Kwan; Hwang, Jin Woo; Kim, Yousok; Cho, Tongjun; Park, Hyo Seon

    2015-11-01

    This paper presents a new vision-based system identification (SI) technique for building structures by using a motion capture system (MCS). The MCS with outstanding capabilities for dynamic response measurements can provide gage-free measurements of vibrations through the convenient installation of multiple markers. In this technique, from the dynamic displacement responses measured by MCS, the dynamic characteristics (natural frequency, mode shape, and damping ratio) of building structures are extracted after the processes of converting the displacement from MCS to acceleration and conducting SI by frequency domain decomposition. A free vibration experiment on a three-story shear frame was conducted to validate the proposed technique. The SI results from the conventional accelerometer-based method were compared with those from the proposed technique and showed good agreement, which confirms the validity and applicability of the proposed vision-based SI technique for building structures. Furthermore, SI directly employing MCS measured displacements to FDD was performed and showed identical results to those of conventional SI method.

  18. Molecular cloaking of H2A.Z on mortal DNA chromosomes during nonrandom segregation.

    Science.gov (United States)

    Huh, Yang Hoon; Sherley, James L

    2011-10-01

    Although nonrandom sister chromatid segregation is a singular property of distributed stem cells (DSCs) that are responsible for renewing and repairing mature vertebrate tissues, both its cellular function and its molecular mechanism remain unknown. This situation persists in part because of the lack of facile methods for detecting and quantifying nonrandom segregating cells and for identifying chromosomes with immortal DNA strands, the cellular molecules that signify nonrandom segregation. During nonrandom segregation, at each mitosis, asymmetrically self-renewing DSCs continuously cosegregate to themselves the set of chromosomes that contain immortal DNA strands, which are the oldest DNA strands. Here, we report the discovery of a molecular asymmetry between segregating sets of immortal chromosomes and opposed mortal chromosomes (i.e., containing the younger set of DNA template strands) that constitutes a new convenient biomarker for detection of cells undergoing nonrandom segregation and direct delineation of chromosomes that bear immortal DNA strands. In both cells engineered with DSC-specific properties and ex vivo-expanded mouse hair follicle stem cells, the histone H2A variant H2A.Z shows specific immunodetection on immortal DNA chromosomes. Cell fixation analyses indicate that H2A.Z is present on mortal chromosomes as well but is cloaked from immunodetection, and the cloaking entity is acid labile. The H2A.Z chromosomal asymmetry produced by molecular cloaking provides a first direct assay for nonrandom segregation and for chromosomes with immortal DNA strands. It also seems likely to manifest an important aspect of the underlying mechanism(s) responsible for nonrandom sister chromatid segregation in DSCs.

  19. An optimization method for the problems of thermal cloaking of material bodies

    Science.gov (United States)

    Alekseev, G. V.; Levin, V. A.

    2016-11-01

    Inverse heat-transfer problems related to constructing special thermal devices such as cloaking shells, thermal-illusion or thermal-camouflage devices, and heat-flux concentrators are studied. The heatdiffusion equation with a variable heat-conductivity coefficient is used as the initial heat-transfer model. An optimization method is used to reduce the above inverse problems to the respective control problem. The solvability of the above control problem is proved, an optimality system that describes necessary extremum conditions is derived, and a numerical algorithm for solving the control problem is proposed.

  20. Pre-Cloak Comic Superheroes: Tools for the Empowerment of Children

    Directory of Open Access Journals (Sweden)

    Chris Fradkin

    2016-09-01

    Full Text Available This note explores the notion of comic superheroes as tools for the empowerment of children. The author details interventions in Rwanda and Brazil, and their different usages of superheroes. With a focus on the superhero’s pre-cloak stage—the stage prior to their employing superpowers—the author offers glimpses of current work in progress to help therapists empower orphaned children. While this area of research is at an early stage, its potential among health professionals is growing. Thus the comic superhero may be more than celluloid, as health professionals learn to use his superpowers.

  1. Hide the interior region of core-shell nanoparticles with quantum invisible cloaks

    CERN Document Server

    Lee, Jeng Yi

    2013-01-01

    By applying the interplay among the nodal points of partial waves, along with the concept of streamline in fluid dynamics for the probability flux, a quantum invisible cloak to the electron transport in a host semiconductor is demonstrated by simultaneously guiding the probability flux outside the core region and keeping the total scattering cross section negligible. As the probability flux vanishes in the interior region, one can embed any material inside a multiple core-shell sphere without affecting physical observables from the outside. Our results reveal the possibility to design a protection shield layer for fragile interior parts from the impact of transports of electrons.

  2. Structural Integrity Evaluation of Cold Neutron Laboratory Building by Design Change of Guide Shielding Room

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Sangik; Kim, Youngki; Kim, Harkrho

    2007-06-15

    This report summarizes the results of the structural integrity evaluation for the cold neutron laboratory building by design change of guide shielding room. The design of the guide shielding room was changed by making its structure members in normal concrete (2.3 g/cc) instead of heavy concrete (3.5 g/cc) because the heavy concrete could be not supplied to meet its design specification. Therefore, it was decided that the guide shielding room is made of the normal concrete. And, the shielding performance of the normal concrete was recalculated to confirm satisfying its design specification, which is of a 9000 zone according to HANARO radiation region classification. The change makes the shielding wall thicker than existing design, and then it is caused to qualify the structural integrity evaluation of the CNLB. Finally, the structural integrity of the CNLB was re-evaluated by considering the design change of the guide shielding room.

  3. Methods for Progressive Collapse Analysis of Building Structures Under Blast and Impact Loads

    Institute of Scientific and Technical Information of China (English)

    LI Zhongxian; SHI Yanchao

    2008-01-01

    Progressive collapse of building structures under blast and impact lcads has attracted great attention all over the world.Prog ressive collapse analysis is essential for an economic and safe design of building structures against progressive collapse to blast and impact loads.Because of the catastrophic nature of progressive collapse and the potentially high cost of constructing or retrofitting buildings to resist it,is imperative that the progressive collapse analysis methods be reliable.For engineers.their methodology to carry out progressve collapse evaluation need not only be accurate and concise.but also be easily used and works fast.Thus,many researchers have been spending lots of effort in developing reliable,efficient and strajghtforward progressive collapse analysis methods recently.In the present paper,currenf progresslve collapse analysis meth ods available in the literature are reviewed.Their suitability,applicability and reliability are dis cussed.Our recent proposed new method for progressive collapse analysis of relnforced concrete frames under blast lcads is also introduced.

  4. Optimization & Design of High Rise Building with Different Structural Framing Systems Subjected To Seismic Loads

    Directory of Open Access Journals (Sweden)

    Mr. Anant A. Kapse ,

    2014-06-01

    Full Text Available Due to excessive displacements of tall buildings occasioned by lateral loads, lateral load resisting systems are usually provided to curtail the load effect. The resistance may be offered by Frame Action, Shear Walls, or combined Walls and Frames (also known as Dual System. In this study, 3D structural modelling base software STAAD-PRO was used to generate and analyze three-dimensional building models for the assessment of the relative effectiveness of the various lateral load resisting systems. Five models were used, one for moment resisting frame & 04 models each for the lateral load resisting systems. Each model consisted of G +10 storey frame structure having total height of 33.0 m. Each building sample was subjected to three-dimensional analysis for the determination of both the lateral displacements at storey top and interstorey drifts. The results of the work showed that the dual system was the most efficient lateral-load resisting system based on deflection criterion, as they yielded the least values for lateral displacements and inter-storey drifts. The moment frame was the least stiff of the resisting systems, yielding the highest values of both the lateral displacement and the inter-storey drift.

  5. Construction technology and major building structure%建筑主体结构的施工技术

    Institute of Scientific and Technical Information of China (English)

    朱靖宇

    2015-01-01

    引入了建筑主体结构的概念,对建筑主体结构的施工情况进行了分析,主要从混凝土施工、钢筋施工、模板施工三个环节阐述了建筑主体结构施工的注意事项,以提高建筑的施工质量,满足用户对建筑的使用需求。%The paper introduces the concept of major building structure, analyzes construction conditions of major building structure, and mainly describe major building structure construction matters from three aspects of concrete construction, steel construction and template construction, with a view to improve the building construction quality and meet users’ utilization demands for building.

  6. Specifications and applications of the technical code for monitoring of building and bridge structures in China

    Directory of Open Access Journals (Sweden)

    Y Yang

    2016-12-01

    Full Text Available Recently, the exclusive compulsory technical code (GB 50982-2014 for structural health monitoring of buildings and bridges in China has been developed and implemented. This code covers the majority of the field monitoring methods and stipulates the corresponding technical parameters for monitoring of high-rise structures, large-span spatial structures, bridges and base-isolated structures. This article first presents the comprehensive review and linear comparison of existing structural health monitoring codes and standards. Subsequently, the progress of the codification of GB 50982-2014 is imparted and its main features and specifications are summarized. Finally, in accordance with GB50982-2014, several representative structural health monitoring practical applications of large-scale infrastructures in China are exemplified to illustrate how this national code can bridge the gap between theory and practical applications of structural health monitoring. This technical code is an important milestone in the application of well-established structural health monitoring techniques into the realistic and complex engineering projects. Also, it can provide abundant and authoritative information for practitioners and researchers involving the structural health monitoring techniques.

  7. Tunable scattering cancellation cloak with plasmonic ellipsoids in the visible

    CERN Document Server

    Fruhnert, Martin; Fernandez-Corbaton, Ivan; Alù, Andrea; Toscano, Alessandro; Bilotti, Filiberto; Rockstuhl, Carsten

    2016-01-01

    The scattering cancellation technique is a powerful tool to reduce the scattered field from electrically small objects in a specific frequency window. The technique relies on covering the object of interest with a shell that scatters light into the far field of equal strength as the object, but $\\pi$ out-of-phase. The resulting destructive interference prohibits its detection in measurements that probe the scattered light. Whereas at radio or microwave frequencies feasible designs have been proposed that allow to tune the operational frequency upon request, similar capabilities have not yet been explored in the visible. However, such ability is decisive to capitalize on the technique in many envisioned applications. Here, we solve the problem and study the use of small metallic nanoparticles with an ellipsoidal shape as the material from which the shell is made to build an isotropic geometry. Changing the aspect ratio of the ellipsoids allows to change the operational frequency. The basic functionality is exp...

  8. Cement stabilized red earth as building block and structural pavement layer

    Directory of Open Access Journals (Sweden)

    G.V. RAMA SUBBARAO

    2014-12-01

    Full Text Available Red Earth is most commonly used as material in the building and road construction. Many a times, the red earth found in various quarries is found not suitable for construction. Cement of 4 and 8% of dry mass of red earth was added to improve its suitability as building block and structural pavement material. To know the influence of waste plastic fiber on cement stabilized red earth, 1% fiber was also added to the mixture. It is shown that the compressive strength of cement stabilized red earth blocks was improved with seven days of curing. The addition of cement to red earth enhanced soaked CBR value. The soaked CBR value of fiber reinforced cement stabilized red earth was about 1.3 to 1.5 times that of unreinforced cement stabilized red earth.

  9. Seismic resistance design of nuclear power plant building structures in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Kitano, Takehito [Kansai Electric Power Co., Inc., Osaka (Japan)

    1997-03-01

    Japan is one of the countries where earthquakes occur most frequently in the world and has incurred a lot of disasters in the past. Therefore, the seismic resistance design of a nuclear power plant plays a very important role in Japan. This report describes the general method of seismic resistance design of a nuclear power plant giving examples of PWR and BWR type reactor buildings in Japan. Nuclear facilities are classified into three seismic classes and is designed according to the corresponding seismic class in Japan. Concerning reactor buildings, the short-term allowable stress design is applied for the S1 seismic load and it is confirmed that the structures have a safety margin against the S2 seismic load. (J.P.N.)

  10. DESIGN OF ENVELOPE STRUCTURES OF BUILDINGS WITH ACCOUNT FOR AND SUBJECT TO THE CONDITIONS OF ACOUSTIC PROTECTION

    Directory of Open Access Journals (Sweden)

    Giyasov Botir Iminzhonovich

    2012-12-01

    Full Text Available The totality of all environmental influences, including domestic and industrial noise, must be taken into account in the design of building structures. Building envelopes that have appropriate acoustic protection properties are to be used in the practice of the acoustic protection (soundproofing, etc.. According to the principles of structural design, design of soundproof buildings can be broken down into the two groups: design with account for the security conditions (eg., windows, doors, walls, floors, and design of noise-proof structures (eg., partitions, suspended ceilings. Multi-optional design of building structures or buildings that meet the terms of acoustic protection requires a modern approach to the process of their development. Any progress in this area is associated with computer-aided design supported by multiple analysis options. Automation allows adjustments in order to comply with the variety of the input data or objective functions to provide for optimal cycling options. In this regard, the authors describe the algorithms and principles of design of building envelopes on the condition of and subject to the acoustic protection. The proposed solution represents a software package capable of performing a multivariate analysis of options of acoustic protection at each stage of building design. Practical application of the software package used to solve practical problems in the design of building envelopes has demonstrated its higher efficiency that the one of traditional design methods.

  11. Base Isolation for Seismic Retrofitting of a Multiple Building Structure: Evaluation of Equivalent Linearization Method

    Directory of Open Access Journals (Sweden)

    Massimiliano Ferraioli

    2016-01-01

    Full Text Available Although the most commonly used isolation systems exhibit nonlinear inelastic behaviour, the equivalent linear elastic analysis is commonly used in the design and assessment of seismic-isolated structures. The paper investigates if the linear elastic model is suitable for the analysis of a seismically isolated multiple building structure. To this aim, its computed responses were compared with those calculated by nonlinear dynamic analysis. A common base isolation plane connects the isolation bearings supporting the adjacent structures. In this situation, the conventional equivalent linear elastic analysis may have some problems of accuracy because this method is calibrated on single base-isolated structures. Moreover, the torsional characteristics of the combined system are significantly different from those of separate isolated buildings. A number of numerical simulations and parametric studies under earthquake excitations were performed. The accuracy of the dynamic response obtained by the equivalent linear elastic model was calculated by the magnitude of the error with respect to the corresponding response considering the nonlinear behaviour of the isolation system. The maximum displacements at the isolation level, the maximum interstorey drifts, and the peak absolute acceleration were selected as the most important response measures. The influence of mass eccentricity, torsion, and high-modes effects was finally investigated.

  12. Comparison of environmental impacts of building structures with in situ cast floors and with precast concrete floors

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Mesa, Belinda; Pitarch, Angel; Tomas, Ana; Gallego, Teresa [Department of Mechanical Engineering and Construction (ESTCE), Universitat Jaume I, Av. Sos Baynat s/n, Castellon 12071 (Spain)

    2009-04-15

    In this paper, the environmental impacts of two types of slab systems are studied. The first type, a concrete-based one-way spanning slab, is the most common solution in residential buildings in Spain. The second type, a hollow core slab floor, is increasingly becoming more used in buildings, but is not being broadly used in residential buildings as yet. The study is undertaken through the Life Cycle Analysis methodology, applying the EPS 2000 method. The assessment shows that the environmental impact of a building structure with precast concrete floors is 12.2% lower than that with in situ cast floors for the defined functional unit. (author)

  13. Extended structure design with simple molybdenum oxide building blocks and urea as a directing agent.

    Science.gov (United States)

    Veen, Sandra J; Roy, Soumyajit; Filinchuk, Yaroslav; Chernyshov, Dmitry; Petukhov, Andrei V; Versluijs-Helder, Marjan; Broersma, Alfred; Soulimani, Fouad; Visser, Tom; Kegel, Willem K

    2008-08-04

    We report here a simple one-pot directed synthesis of an oxomolybdate urea composite in which elementary molybdenum oxide building blocks are linked together with the aid of urea. This type of directed material design resulted in large rod-like crystals of an inorganic-organic hybrid extended structure of {MoO 3(NH 2-CO-NH 2)} infinity consisting of right- and left-handed helical units. In the crystal structure urea acts both as a glue that links the inorganic molybdenum units into a helix and as a supramolecular linker for the stabilization of the crystal structure as a whole. This type of molecular topology resulted in an unexpectedly high thermal stability.

  14. Investigation of the structural form optimization methods of high-rise buildings

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shihai; WANG Li; OU Jinping; WANG Guangyuan

    2007-01-01

    In this paper, the structural form optimization methods of high-rise buildings based on the expert system (ES), case-based reasoning (CBR), and knowledge discovery in database (KDD) are evaluated systematically. The charac- teristics and shortcomings of each method are pointed out. It is predicted that the incorporation of these three techniques into an intelligent form optimization method will be an important development direction in the future. Finally, the unified intelligent form selection model combined with concepts of ES, CBR, KDD and artificially intelligent beauti- fication is proposed. In consideration of the needs of human beings, machinery and computation, the model has been used for structural design combined with relevant knowledge, means, maneuver and strategy. The model plays an important role and has practical value in the process of artificially intelligent form optimization. It effectively reduces the blindness and failure of computer-aided structural design.

  15. Cellulose-builder: a toolkit for building crystalline structures of cellulose.

    Science.gov (United States)

    Gomes, Thiago C F; Skaf, Munir S

    2012-05-30

    Cellulose-builder is a user-friendly program that builds crystalline structures of cellulose of different sizes and geometries. The program generates Cartesian coordinates for all atoms of the specified structure in the Protein Data Bank format, suitable for using as starting configurations in molecular dynamics simulations and other calculations. Crystalline structures of cellulose polymorphs Iα, Iβ, II, and III(I) of practically any size are readily constructed which includes parallelepipeds, plant cell wall cellulose elementary fibrils of any length, and monolayers. Periodic boundary conditions along the crystallographic directions are easily imposed. The program also generates atom connectivity file in PSF format, required by well-known simulation packages such as NAMD, CHARMM, and others. Cellulose-builder is based on the Bash programming language and should run on practically any Unix-like platform, demands very modest hardware, and is freely available for download from ftp://ftp.iqm.unicamp.br/pub/cellulose-builder.

  16. Life-Cycle Assessment of Seismic Retrofit Strategies Applied to Existing Building Structures

    Directory of Open Access Journals (Sweden)

    Umberto Vitiello

    2016-12-01

    Full Text Available In the last few years, the renovation and refurbishment of existing buildings have become the main activities of the construction industry. In particular, many studies have recently focused on the mechanical and energy performances of existing retrofitted/refurbished facilities, while some research has addressed the environmental effects of such operations. The present study aims to assess the environmental impact of some retrofit interventions on an existing reinforced concrete (RC building. Once the structural requirements have been satisfied and the environmental effects of these retrofit solutions defined, the final purpose of this study is to identify the most environmentally sustainable retrofit strategy. The environmental impact of the structural retrofit options is assessed using a life-cycle assessment (LCA. This paper sets out a systematic approach that can be adopted when choosing the best structural retrofit option in terms of sustainability performance. The final aim of the study is to also provide a tool for researchers and practitioners that reflects a deep understanding of the sustainability aspects of retrofit operations and can be used for future researches or practical activities.

  17. Optimal Thermo-Structural Analysis for High Density Package Mounting on Build-up Board

    Science.gov (United States)

    Nakanishi, Tohru; Hase, Tomohiro

    The importance of the high density packaging technology and mounting technology on the printed wiring build-up board has been increased for the consumer electric products. On the other hand, the chance to use the build-up boards for mounting the high density packages has been increased. However, the understanding that the reliability of the solder connection depends on the structure of the package, the motherboard, and the material properties, is not very high. In this paper, the reliability for high density packaging, mounted on the build-up board, is assessed. The compact numerical analysis model for the reliability assessment is suggested and the most reliable packaging design with optimizing each of the parameters is reported. For introduction to the reliability assessment of the FCA attachment, ceramic and silicon are compared as the inter-poser with the parameter of the solder height. The verification of the numerical analysis results using tests on the actual hardware is also shown. And the established numerical analysis model is applied to the study of influence of the copper balance between the front side and the back side copper layers.

  18. Analytical Model of Underground Train Induced Vibrations on Nearby Building Structures in Cameroon: Assessment and Prediction

    Directory of Open Access Journals (Sweden)

    Lezin Seba MINSILI

    2013-11-01

    Full Text Available The purpose of this research paper was to assess and predict the effect of vibrations induced by an underground railway on nearby-existing buildings prior to the construction of projected new railway lines of the National Railway Master Plan of Cameroon and after upgrading of the railway conceded to CAMRAIL linking the two most densely populated cities of Cameroon: Douala and Yaoundé. With the source-transmitter-receiver mathematical model as the train-soil-structure interaction model, taking into account sub-model parameters such as type of the train-railway system, typical geotechnical conditions of the ground and the sensitivity of the nearby buildings, the analysis is carried out over the entire system using the dynamic finite element method in the time domain. This subdivision of the model is a powerful tool that allows to consider different alternatives of sub-models with different characteristics, and thus to determine any critical excessive vibration impact. Based on semi-empirical analytical results obtained from presented models, the present work assesses and predicts characteristics of traffic-induced vibrations as a function of time duration, intensity and vehicle speed, as well as their influence on buildings at different levels.

  19. INTEGRATED PURIFICATION OF VENTILATED AIR IN AIR LAYERS OF DAMP BUILDING STRUCTURES

    Directory of Open Access Journals (Sweden)

    V. V. Shitov

    2011-04-01

    Full Text Available Problem statement. Intensive wear of the structure bearing elements in premises with high moisture content in ventilated air is associated with cyclic changes in temperature and humidity indicators of steam-air environment; hence, the problem of ventilated air treatment in such premises is topical.Results. The design of device for integrated purification of atmospheric ventilated air from fine-dispersed pollutants in premise with high moisture content in indoor air is developed.Conclusions. The proposed device provides reliable and long-term operation of bearing building elements.

  20. Vibrationproof Design for Building Structures%建筑结构防振设计

    Institute of Scientific and Technical Information of China (English)

    茅玉泉; 辛兰琴

    2012-01-01

    建筑结构防振设计涉及到建筑物内部精密设备、仪器、仪表的精密度,机械设备和操作的工作条件,工作人员的舒适度,建筑物的安全和耐久性,以及不致影响其使用的容许振动防振指标.防振的主要措施:通过厂址选择,远离强振动、强噪声、强风沙、强电磁波辐射、有害气体液体等污染和不良环境;厂区和车间的合理布置,振源和精密设备相对集中、互相远离,尽量满足允许振动的防振距离要求;建筑结构本身要使得其基本频率避开共振区,构造上要采取局部加强以减弱振动影响;室内气流控制低速、门窗要求弹性密闭等.若还难以满足允许振动要求,则需要采取对有害振源的隔振,或对受振精密设备、仪器、仪表采取隔振(必要时采取同时隔振),从而满足不同设备、人、建筑物的防振指标要求.%Vibrationproof design for building structures is important esp for precision equipment and instruments/meters in the building. Working conditions of mechanical equipment and operators, the safety and durability of buildings as well as vibrationproof index are required for allowable vibration. For the vibrationproof of building structures, such measures shall be taken: (1) Selecting proper site location, keeping away from regional intensified vibration, high level of noise, strong wind/sand, strong electromagnetic radiation, harmful gases/liquids, pollution and poor environment; ( 2 ) Design in plant/workshop layout rationally, grouping the vibration sources and precision equipment relatively and respectively and meeting the requirements of vibrationproof distance; ( 3 ) Consideration for the building structures, avoiding resonance zones; ( 4 ) Structural design in reinforcing the structure, keeping low indoor air speed and ensureing good tightness of doors/windows. If the vibrationproof requirements can not be satisfied, vibration isolation measures shall be taken to. the

  1. Three-dimensional structures of human phospholipase A2 from pancreas and synovial fluid by model building

    DEFF Research Database (Denmark)

    Christensen, I T; Jørgensen, Flemming Steen; Svensson, L A;

    1993-01-01

    Three-dimensional structures of the enzyme phospholipase A2 (PLA2) from human pancreas and from human synovial fluid were constructed by model building based on high-resolution X-ray crystallographic structures and homology considerations. The structure of the human pancreatic PLA2 was based on t...

  2. Structural Model for the Effects of Perceived Indoor Work Environment on Sick Building Syndrome and Stress

    Directory of Open Access Journals (Sweden)

    Abdullah Nor Hazana

    2016-01-01

    Full Text Available Sick Building syndrome (SBS and stress have a prevalent influence on organizational productivity and competitiveness. Unhealthy employees not only tend to have high medical leaves but also low productivity due to ailments and discomforts. Studies that investigate the effects of indoor work environment on Sick Building Syndrome (SBS have yielded mixed results while their effect on stress has not been empirically established. Furthermore, studies that simultaneously investigate both SBS and stress are almost non-existent. Thus, this study aimed to study the effects of perceived indoor work environment on SBS and stress and the link between SBS and stress. A cross-sectional survey participated by 598 employees from various industries was conducted from September to October 2015. Data were analyzed using Partial Least Square Structural Equation Modeling (PLS-SEM to assess both the measurement model and the path structure. The results suggest that indoor work environment has significant yet the weak effect on SBS while it has no effect on stress. However, SBS has a strong significant relationship with stress. The implication of this study on the importance of conducive indoor work environment is discussed with suggestions for future studies.

  3. TEACHING OPTIMIZATION OF STUDENTS AT DESIGN OF BUILDINGS AND STRUCTURES FOUNDATIONS

    Directory of Open Access Journals (Sweden)

    MISURA Lid. V.

    2016-04-01

    Full Text Available Raising of problem. According to world statistics, more than 75 % of all violations of the normal operation of buildings and structures is due to deficiencies in the design, construction and operation of bases and foundations [1]. The costs to eliminate these negative effects can be compared only with the initial cost of construction, it speaks about the relevance of teaching subjects related to the design of foundations. On the other hand increased demands on the students' knowledge, raises the amount of information that needs to absorb at constant periods of instruction, which makes the current process optimization study of these disciplines. Purpose. The aim of the article is to present the software package that allows to facilitate and accelerate the calculation and check the parameters of foundations and bases for the design of buildings and structures. The software product is designed as an educational complex, which allows the student to help with the calculations in different levels of difficulty and test his knowledge. Conclusion. The program complex, which consists of a program for dimensioning the foundations, the program for calculating the parameters of the bases, of the database. It is confirmed stable operation of the school complex (the program, measures were taken to test the program, helped to make it stable. The training complex is designed only for shallow foundations, so the work will be continued.

  4. Pushing the Envelope: A Case Study of Building the First Manufactured Home Using Structural Insulated Panels

    Energy Technology Data Exchange (ETDEWEB)

    Baechler, Michael C.; Hadley, Donald L.; Sparkman, Ronald; Lubliner, Michael

    2002-06-01

    This paper for the ACEEE Summer Study describes construction of the first manufactured home ever produced from structural insulated panels. The home was built in July 2000 by Champion Enterprises at its Silverton, Oregon, plant. The house was completed on the assembly line in 9 days including a 300-mile road test. The paper examines the design and approval process leading to the project, the manufacturing process and its adjustment to SIPs, and the transportation and energy performance of the house after it was built. PNNL coordinated this project and conducted long-term monitoring on the house. The WSU Energy Program conducted building diagnostics testing once the house was occupied. PNNL’s and WSU’s involvement was funded by the U.S. DOE Building America Program. The Oregon Office of Energy conducted blower door and duct blaster tests. The completed home was estimated to reduce energy consumption by 50% and to have twice the structural strength required by HUD code for manufactured homes. The demonstration proved that the manufactured home production line could support SIPs production simultaneously with traditional construction and without major modifications, the line work in parallel with SIPs and traditional materials. The project revealed severl possibilities for further improving cost and time savings with SIPs construction, that might translate into increased capacity.

  5. Structure build-up and evolution in the drying of sessile blood droplets

    Science.gov (United States)

    Craster, Richard; Uppal, Aran; Matar, Omar

    2016-11-01

    Experimental observations have recorded blood undergoing a sol-gel transition during the evaporation process. Consequently, the rheology becomes non-uniform throughout the droplet and exhibits transitional complex phenomena that we must capture if we wish to accurately model the evaporative/cracking process. We propose a model where thixotropy is introduced to capture the evolving rheology as evaporation occurs. Thixotropy is often used to describe fluids which exhibit a decrease in viscosity due to flow and subsequent slow recovery of viscosity after the cessation of the flow. We introduce an additional parameter to describe the internal structure of the fluid at each point and consider a droplet in the limit of the lubrication approximation. We present a discussion of our results that demonstrates the dependence of structure build-up, which accompanies the spatio-temporal evolution of the drop, on system parameters. EPSRC UK Centre for Doctoral Training.

  6. Application of experimental design techniques to structural simulation meta-model building using neural network

    Institute of Scientific and Technical Information of China (English)

    费庆国; 张令弥

    2004-01-01

    Neural networks are being used to construct meta-models in numerical simulation of structures. In addition to network structures and training algorithms, training samples also greatly affect the accuracy of neural network models. In this paper, some existing main sampling techniques are evaluated, including techniques based on experimental design theory,random selection, and rotating sampling. First, advantages and disadvantages of each technique are reviewed. Then, seven techniques are used to generate samples for training radial neural networks models for two benchmarks: an antenna model and an aircraft model. Results show that the uniform design, in which the number of samples and mean square error network models are considered, is the best sampling technique for neural network based meta-model building.

  7. Vibration control of building structures using self-organizing and self-learning neural networks

    Science.gov (United States)

    Madan, Alok

    2005-11-01

    Past research in artificial intelligence establishes that artificial neural networks (ANN) are effective and efficient computational processors for performing a variety of tasks including pattern recognition, classification, associative recall, combinatorial problem solving, adaptive control, multi-sensor data fusion, noise filtering and data compression, modelling and forecasting. The paper presents a potentially feasible approach for training ANN in active control of earthquake-induced vibrations in building structures without the aid of teacher signals (i.e. target control forces). A counter-propagation neural network is trained to output the control forces that are required to reduce the structural vibrations in the absence of any feedback on the correctness of the output control forces (i.e. without any information on the errors in output activations of the network). The present study shows that, in principle, the counter-propagation network (CPN) can learn from the control environment to compute the required control forces without the supervision of a teacher (unsupervised learning). Simulated case studies are presented to demonstrate the feasibility of implementing the unsupervised learning approach in ANN for effective vibration control of structures under the influence of earthquake ground motions. The proposed learning methodology obviates the need for developing a mathematical model of structural dynamics or training a separate neural network to emulate the structural response for implementation in practice.

  8. Acoustic cloaking by a near-zero-index phononic crystal

    KAUST Repository

    Zheng, Li-Yang

    2014-04-21

    Zero-refractive-index materials may lead to promising applications in various fields. Here, we design and fabricate a near Zero-Refractive-Index (ZRI) material using a phononic crystal (PC) composed of a square array of densely packed square iron rods in air. The dispersion relation exhibits a nearly flat band across the Brillouin zone at the reduced frequency f  = 0.5443c/a, which is due to Fabry-Perot (FP) resonance. By using a retrieval method, we find that both the effective mass density and the reciprocal of the effective bulk modulus are close to zero at frequencies near the flat band. We also propose an equivalent tube network model to explain the mechanisms of the near ZRI effect. This FP-resonance-induced near ZRI material offers intriguing wave manipulation properties. We demonstrate both numerically and experimentally its ability to shield a scattering obstacle and guide acoustic waves through a bent structure.

  9. Review of the use of phase change materials (PCMs in buildings with reinforced concrete structures

    Directory of Open Access Journals (Sweden)

    Pons, O.

    2014-09-01

    Full Text Available Phase change materials are capable of storing and releasing energy in the form of heat in determined temperature ranges, so to increase a building’s thermal inertia, stabilize its indoor temperatures and reduce its energetic demand. Therefore, if we used these materials we could have more energetically efficient buildings. Nevertheless, are these materials most appropriate to be used in buildings? Could the incorporation of phase change materials in buildings with concrete structures be generalized? This article aims to carry out a review of these phase change materials from construction professionals’ points of view, study their applications for buildings with reinforced concrete structures and the key points for these applications, draw conclusions and provide recommendations useful for all professionals within the sector who are considering the application of these materials.Los materiales de cambio de fase son capaces de almacenar y liberar energía en forma de calor en un determinando rango de temperaturas, y así aumentar la inercia térmica de un edificio, estabilizar las temperaturas en el interior y reducir la demanda energética. En consecuencia, si utilizáramos estos materiales podríamos tener un parque de edificios más eficientes energéticamente. No obstante, ¿estos materiales son apropiados para usarse en edificios? ¿Se podría generalizar la incorporación de materiales de cambio de fase en edificios con estructuras de hormigón? Este artículo tiene como objetivos hacer una revisión del estado del arte de estos materiales de cambio de fase desde el punto de vista de los profesionales de la construcción, estudiar las aplicaciones en edificios con estructuras de hormigón armado y los puntos clave para estas aplicaciones, extraer conclusiones y recomendaciones útiles para los profesionales del sector que se planteen la utilización de estos materiales.

  10. Experimental and Numerical Analysis of Thermal and Hygrometric Characteristics of Building Structures Employing Recycled Plastic Aggregates and Geopolymer Concrete

    Directory of Open Access Journals (Sweden)

    Francesco Colangelo

    2013-11-01

    Full Text Available The correct estimation of building energy consumptions is assuming an always increasing importance, and a detailed reproduction of building structures, with all the single components involved, is necessary to achieve this aim. In addition, the current ecological development tries to limit the use of natural raw materials as building components, in favor of alternative (waste materials, which ensure significant advantages from the economic, energetic and environmental point of views. In this work, dynamic heat and vapor transport in a typical three-dimensional (3D building structure, involving different types of environmental-friendly concrete mixtures, have been simulated by using finite elements. In particular, the authors propose to substitute part of the aggregates with plastic waste and to use a fly ash based geopolymeric binder for the production of low conductivity concrete, to be employed in eco-efficient buildings. Concrete produced with natural limestone aggregates has been considered as the reference benchmark. The whole characterization of the different types of concrete tested in the present work has been obtained through laboratory experiments. The structure taken into account in the simulations is a 3D thermal bridge, typical of building envelopes. The thermal and hygrometric transient behavior of this structure, employing plastic waste in different percentages and geopolymer concrete, has been analyzed by the authors.

  11. Synergistic proinflammatory interactions of microbial toxins and structural components characteristic to moisture-damaged buildings.

    Science.gov (United States)

    Korkalainen, M; Täubel, M; Naarala, J; Kirjavainen, P; Koistinen, A; Hyvärinen, A; Komulainen, H; Viluksela, M

    2017-01-01

    Indoor exposure to microbes and their structural and metabolic compounds is notoriously complex. To study proinflammatory interactions between the multiple microbial agents, macrophages derived from human THP-1 monocytic cells were exposed to several concentrations of microbial toxins alone (emodin, enniatin B, physcion, sterigmatocystin, valinomycin) and in combination with microbial structural components (bacterial lipopolysaccharide [LPS] or fungal β-glucan). While the expression of proinflammatory cytokines TNFα and IL-1β to single toxins alone was modest, low-dose co-exposure with structural components increased the responses of emodin, enniatin B, and valinomycin synergistically, both at the mRNA and protein level, as measured by RT-qPCR and ELISA, respectively. Co-exposure of toxins and β-glucan resulted in consistent synergistically increased expression of several inflammation-related genes, while some of the responses with LPS were also inhibitory. Co-exposure of toxins with either β-glucan or LPS induced also mitochondrial damage and autophagocytosis. The results demonstrate that microbial toxins together with bacterial and fungal structural components characteristic to moisture-damaged buildings can have drastic synergistic proinflammatory interactions at low exposure levels.

  12. 办公楼绿色建筑结构设计%Green Structural Design of Office Building

    Institute of Scientific and Technical Information of China (English)

    孔德欣

    2015-01-01

    我国正处于绿色建筑加速发展时期,节能设计与建筑能耗的问题越来越受到广泛的重视。通过某办公楼绿色建筑结构设计实例,对绿色建筑结构的体系选型、优化设计等方面进行阐述,为类似工程提供参考。%China is in a period of accelerated development of green building, and energy-saving design and building energy consumption problem is getting wide attention. Through the example of green structure design of a office building, the selection and optimized design of the green building structure are elaborated to provide reference for similar projects.

  13. Localization of the places of stress-strain state changes of building structures based on the vibrodiagnostic measurement data

    Directory of Open Access Journals (Sweden)

    Shakhraman'yan Andrey Mikhaylovich

    Full Text Available The method of localization of changes in the deflected mode is based on the analysis of time series of oscillations (displacement, velocity, acceleration of building constructions and structures. The method is based on the hypothesis that any changes in the deflected mode of structures result in changes in the oscillation energy. In this case, once the information on the structure oscillation parameters in different points of the building is available, the changes in the oscillation energy will signify the changes in the deflected mode in the relevant points.

  14. Characterization of changes in commercial building structure, equipment, and occupants: End-Use Load and Consumer Assessment Program

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, R.G.; Taylor, Z.T.; Miller, N.E.; Pratt, R.G.

    1990-12-01

    Changes in commercial building structure, equipment, and occupants result in changes in building energy use. The frequency and magnitude of those changes have substantial implications for conservation programs and resource planning. For example, changes may shorten the useful lifetime of a conservation measure as well as impact the savings from that measure. This report summarizes the frequency of changes in a commercial building sample that was end-use metered under the End-Use Load and Consumer Assessment Program (ELCAP). The sample includes offices, dry good retails, groceries, restaurants, warehouses, schools, and hotels. Two years of metered data, site visit records, and audit data were examined for evidence of building changes. The observed changes were then classified into 12 categories, which included business type, equipment, remodel, vacancy, and operating schedule. The analysis characterized changes in terms of frequency of types of change; relationship to building vintage and floor area; and variation by building type. The analysis also examined the energy impacts of various changes. The analysis determined that the rate of change in commercial buildings is high--50% of the buildings experienced one type of change during the 2 years for which monitoring data were examined. Equipment changes were found to be most frequent in offices and retail stores. Larger, older office buildings tend to experience a wider variety of changes more frequently than the smaller, newer buildings. Key findings and observations are presented in Section 2. Section 3 provides the underlying motivation and objectives. In Section 4, the methodology used is documented, including the commercial building sample and the data sources used. Included are the definitions of change events and the overall approach taken. Results are analyzed in Section 5, with additional technical details in Appendixes. 2 refs., 46 figs., 22 tabs. (JF)

  15. Building Collaborative Structures for Teachers' Autonomy and Self-Efficacy: The Mediating Role of Participative Management and Learning Culture

    Science.gov (United States)

    Lu, Jiafang; Jiang, Xinhui; Yu, Huen; Li, Dongyu

    2015-01-01

    This study focused on the collaborative structure-building behavior of school principals and examined how such behavior affects teacher empowerment. More important, it tested the mediating effects of participative management and learning culture. By collecting nested data from 104 schools in Hong Kong and adopting multilevel structural equation…

  16. Structure, Mechanism, and Application of Vacuum Insulation Panels in Chinese Buildings

    Directory of Open Access Journals (Sweden)

    Changhai Peng

    2016-01-01

    Full Text Available Thermal insulation is one of the most used approaches to reduce energy consumption in buildings. Vacuum insulation panels (VIPs are new thermal insulation materials that have been used in the domestic and overseas market in the last 20 years. Due to the vacuum thermal insulation technology of these new materials, their thermal conductivity can be as low as 0.004 W/(m·K at the center of panels. In addition, VIPs that are composites with inorganic core and an envelope out of commonly three metallized PET layers and a PE sealing layer can provide B class fire resistance (their core materials are not flammable and are classified as A1. Compared with other conventional thermal insulation materials, the thermal insulation and fire resistance performances form the foundation of VIP’s applications in the construction industry. The structure and thermal insulation mechanism of VIP and their application potential and problems in Chinese buildings are described in detail.

  17. The man in the scarlet cloak. The mysterious death of Peter Anthony Motteux.

    Science.gov (United States)

    Ober, W B

    1991-09-01

    Peter Anthony Motteux (1663-1718), a Huguenot refugee in London, established a literary reputation by completing Sir Thomas Urquhart's translation of Rabelais' Gargantua and Pantagruel, then Cervantes' Don Quixote. He later became an import-export merchant. On his 55th birthday he donned his scarlet cloak and went out on the town. He picked up a prostitute and after some dalliance returned to her bordello. Shortly thereafter he was found dead, although the evidence is that he was in good health when he arrived. Literary evidence is that he died from assisted erotic asphyxia, a variant of autoerotic asphyxia, cf. the case of Frantisek Koczwara (Am J Forensic Med Pathol 5:145-149, 1984.)

  18. A fundamental Lagrangian approach to transformation acoustics and spherical spacetime cloaking

    Science.gov (United States)

    Tung, Michael M.

    2012-05-01

    Transformation acoustics centers on the construction of advanced acoustic devices by combining mathematical transformation techniques with the engineering of acoustic metamaterials. We show how differential-geometric methods together with a variational principle form the basis of a powerful framework to control acoustic waves as desired. This formalism is required to leave the acoustic wave equation invariant under coordinate transformations and is shown to consist of a proposed acoustic Lagrangian function on a smooth spacetime manifold. As an immediate consequence, we can derive the general constitutive relations between the acoustic parameters (bulk modulus and mass-density tensor) of the physical and virtual spaces under consideration. We conclude with a practical application of this theory by presenting acoustic spherical cloaking with time dilation.

  19. Effects of reinforcement ratio and arrangement on the structural behavior of a nuclear building under aircraft impact

    Energy Technology Data Exchange (ETDEWEB)

    Thai, Duc-Kien; Kim, Seung-Eock, E-mail: sekim@sejong.ac.kr; Lee, Hyuk-Kee

    2014-09-15

    Highlights: • Numerical analysis of RC nuclear building model under aircraft impact was conducted. • The analysis result shows similar behavior as compared to the Riera function. • The effects of reinforcement ratio and arrangement were enumerated. • The appropriate number of layer of longitudinal rebar was recommended. - Abstract: This study presents the effectiveness of the rebar ratio and the arrangement of reinforced concrete (RC) structures on the structural behavior of nuclear buildings under aircraft impact using a finite element (FE) approach. A simplified model of a fictitious nuclear building using RC structures was fully modeled. The aircraft model of a Boeing 767-400 was used for impact simulation and was developed and verified with a conventional impact force–time history curve. The IRIS Punching test was used to validate the damage prediction capabilities of the RC wall under impact loading. With regard to the different rebar ratios and rebar arrangements of a nuclear RC building, the structural behavior of a building under aircraft impact was investigated. The structural behavior investigated included plastic deformation, displacement, energy dissipation, perforation/penetration depth and scabbing area. The results showed that the rebar ratio has a significant effect on withstanding aircraft impact and reducing local damage. With four layers of rebar, the RC wall absorbed and dissipated the impact energy more than once with only two layers of rebar for the same rebar ratio.

  20. Remote sensing of voids in large concrete structures: runways, taxiways, bridges, and building walls and roofs

    Science.gov (United States)

    Weil, Gary J.

    1998-10-01

    Maintenance of our world's infrastructure presents many unique challenges. Engineering and maintenance personnel must maintain around the clock service to millions of people each year while maintaining millions of cubic meters of concrete distributed throughout facilities. This infrastructure includes runways, taxiways, roadways, walkways, bridges, building walls and roofs. Presently only a limited number of accurate and economical techniques exist to test this myriad of concrete structures for integrity and safety as well as insure that they meet original design specifications. Remote sensing, non-destructive testing techniques, such as Infrared Thermography, Ground Penetrating Radar, Magnetometer and Pachometer, measure physical properties affected by the various materials and conditions found within, and under, concrete infrastructure. These techniques have established reputations for accurate investigations of concrete anomalies. This paper will review the applications of different non- destructive testing techniques on many concrete infrastructure components.

  1. Nondestructive testing of airport concrete structures: runways, taxiways, roads, bridges, building walls, and roofs

    Science.gov (United States)

    Weil, Gary J.

    1998-03-01

    Maintenance of airport infrastructure presents many unique challenges. Airport engineering and maintenance personnel must maintain around the clock service to millions of people each year while maintaining millions of cubic meters of concrete distributed throughout the facilities. This infrastructure includes runways, taxiways, roadways, walkways, bridges, building walls and roofs. Presently only a limited number of accurate and economical techniques exist to test this myriad of concrete structures for integrity and safety as well as insure that they meet original design specifications. Remote sensing, non-destructive testing techniques, such as IR thermography, ground penetrating radar, magnetometer and pachometer, measure physical properties affected by the various materials and conditions found within, and under, concrete infrastructure. These techniques have established reputations for accurate investigations of concrete anomalies.

  2. Building disc structure and galaxy properties through angular momentum: The DARK SAGE semi-analytic model

    CERN Document Server

    Stevens, Adam R H; Mutch, Simon J

    2016-01-01

    We present the new semi-analytic model of galaxy evolution, DARK SAGE, a heavily modified version of the publicly available SAGE code. The model is designed for detailed evolution of galactic discs. We evolve discs in a series of annuli with fixed specific angular momentum, which allows us to make predictions for the radial and angular-momentum structure of galaxies. Most physical processes, including all channels of star formation and associated feedback, are performed in these annuli. We present the surface density profiles of our model spiral galaxies, both as a function of radius and specific angular momentum, and find the discs naturally build a pseduobulge-like component. Our main results are focussed on predictions relating to the integrated mass--specific angular momentum relation of stellar discs. The model produces a distinct sequence between these properties in remarkable agreement with recent observational literature. We investigate the impact Toomre disc instabilities have on shaping this sequenc...

  3. Experimental study of wind loads on unique buildings and structures in Russia

    Directory of Open Access Journals (Sweden)

    Poddaeva Olga

    2016-01-01

    Full Text Available Design and construction of unique buildings and structures (sports arenas, airport complexes, business centres, etc. from an engineering point of view is a very difficult task as in most cases these facilities have an original architectural form. Therefore, consideration of wind loads is an important part of the design. The paper presents the definition of wind load for two complex of airport. Researches was applied the combined calculation an experimental method. During the experimental study a wind tunnel architectural and construction type NRU MSUCE was used. Numerical simulations were performed using the software package ANSYS. The result of research on each object are integral aerodynamic loads on the object (coefficients Cx, Cy, Cmz and picture of the distribution of aerodynamic pressure coefficient Cp obtained in the numerical simulation. In conclusion, we discuss the possible formation of deposits of snow and recommendations to eliminate them from the roof of researched objects.

  4. Software package to automate the design and production of translucent building structures made of pvc

    Directory of Open Access Journals (Sweden)

    Petrova Irina Yur’evna

    2016-08-01

    Full Text Available The article describes the features of the design and production of translucent building structures made of PVC. The analysis of the automation systems of this process currently existing on the market is carried out, their advantages and disadvantages are identified. Basing on this analysis, a set of requirements for automation systems for the design and production of translucent building structures made of PVC is formulated; the basic entities are involved in those business processes. The necessary functions for the main application and for dealers’ application are specified. The main application is based on technological platform 1C: Enterprise 8.2. The dealers’ module is .NET application and is developed with the use of Microsoft Visual Studio and Microsoft SQL Server because these software products have client versions free for end users (.NET Framework 4.0 Client Profile and Microsoft SQL Server 2008 Express. The features of the developed software complex implementation are described; the relevant charts are given. The scheme of system deployment and protocols of data exchange between 1C server, 1C client and dealer is presented. Also the functions supported by 1C module and .NET module are described. The article describes the content of class library developed for .NET module. The specification of integration of the two applications in a single software package is given. The features of the GUI organization are described; the corresponding screenshots are given. The possible ways of further development of the described software complex are presented and a conclusion about its competitiveness and expediency of new researches is made.

  5. Structural analyses of the storage container for heavy element facility, building-251

    Energy Technology Data Exchange (ETDEWEB)

    Ng, D S

    1999-01-01

    The Heavy Element Facility, Building 251, contains a series of underground storage vaults which are used for long term storage of nuclear materials. A storage rack with shelves is suspended from the top of each storage vault. The stainless steel containers enclosing the nuclear materials are stored on the shelves. A Hazard & Accident assessment analyzed the vulnerability of this storage system to assaults resulting from natural phenomena and accidents within the building. The assessment considered all racks and their containers to be stored underground and secured in their static, long-term configuration. Moving beyond the static, long-term hazard assessment, the structural analyses were performed to evaluate the storage container against a rare, short duration event. An accidental free drop of a container may occur in a combination of two events: a rare, short-duration earthquake concurrent with an operation of raising the storage rack to a maximum height that the crane is capable of. This hypothetical free drop may occur only to the container in the uppermost shelf of the storage rack. The analyses were the structural evaluation of the storage container to determine the material containment integrity of the storage container after the accident. The evaluation was performed simulating a free drop from the storage rack, with a maximum load in the container, striking/an unyielding surface in the worst orientation. The analyses revealed that, in the very unlikely event of a container drop, the integrity of the hermetic seal of the storage container could be compromised due to plastic deformation of the lid and mating flange. Simple engineering and administrative controls can prevent that from occurring.

  6. A modified Kelvin impact model for pounding simulation of base-isolated building with adjacent structures

    Institute of Scientific and Technical Information of China (English)

    Ye Kun; Li Li; Zhu Hongping

    2009-01-01

    Base isolation can effectively reduce the seismic forces on a superstructure, particularly in low- to medium-rise buildings. However, under strong near-fault ground motions, pounding may occur at the isolation level between the base-isolated building (BIB) and its surrounding retaining walls. To effectively investigate the behavior of the BIB pounding with adjacent structures, after assessing some commonly used impact models, a modified Kelvin impact model is proposed in this paper. Relevant parameters in the modified Kelvin model are theoretically derived and numerically verified through a simple pounding case. At the same time, inelasticity of the isolated superstructure is introduced in order to accurately evaluate the potential damage to the superstructure caused by the pounding of the BIB with adjacent structures. The reliability of the modified Kelvin impact model is validated through numerical comparisons with other impact models. However, the difference between the numerical results from the various impact analytical models is not significant. Many numerical simulations of BIBs are conducted to investigate the influence of various design parameters and conditions on the peak inter-story drills and floor accelerations during pounding. It is shown that pounding can substantially increase floor accelerations, especially at the ground floor where impacts occur. Higher modes of vibration are excited during poundings, increasing the inter-story drifts instead of keeping a nearly rigid-body motion of the superstructure. Furthermore, higher ductility demands can be imposed on lower floors of the superstructure. Moreover, impact stiffness seems to play a significant role in the acceleration response at the isolation level and the inter-story drifts of lower floors of the superstructure. Finally, the numerical results show that excessive flexibility of the isolation system used to minimize the floor accelerations may cause the BIB to be more susceptible to pounding

  7. Influence of the Soil-Structure Interaction on the Design of Steel-Braced Building Foundation

    Science.gov (United States)

    Azarbakht, Alireza; Ashtiany, Mohsen Ghafory

    2008-07-01

    The modeling and analysis of the superstructure and the foundation for the seismic lateral loads are traditionally done separately. This assumption is an important issue in the design/rehabilitate procedures especially for the short period structures, i.e. steel braced or shear wall systems, which may result to a conservative design. By using more advance procedures, i.e. nonlinear static method, and the incorporation of the soil-structure interaction (SSI), the seismic demand in the lateral resisting system decreases and the design will become more economic. This paper includes an investigation about the influence of the SSI effect on the design of the steel-braced building foundation. The presented example is a three-bay three-storey steel braced frame. Three design methods based on the FEMA 356 guideline and the UBC 97 code are taken in to consideration. The three methods are: (1) linear static analysis based on the UBC 97 code assuming the fixed based condition; (2) linear static analysis based on the FEMA 356 guideline assuming the fixed based condition; and (3) nonlinear static analysis assuming both fixed and flexible based assumptions. The results show that the influence of the SSI on the input demand of the short period building foundations is significant and the foundation design based on the linear static method with the fixed base assumption is so conservative. A simple method is proposed to take the SSI effect in to consideration in the linear static procedure with the fixed base assumption, which is a common method for the engineers. The advantage of this proposed method is the simplicity and the applicability for the engineering purposes.

  8. Structural Influence on Superatomic Orbitals of Typical Gold Nanostructure Building Blocks

    Science.gov (United States)

    Jiang, Wanrun; Gao, Yang; Xu, Dexuan; Liu, Fang; Wang, Zhigang

    2016-10-01

    We compared superatomic orbitals mainly contributed by 6s atomic orbitals among spherical core-shell cluster Au13, hexagonal plane Au7 and a (5,5) nanotube segment Au35 through first-principles density functional theory calculations. The compatibility between geometry and orbital morphology influences both the presence and the energy level order of particular superatomic orbitals. Taking Au13 as a reference, which possesses a regular configuration of 1S 21P 61D 5, the hexagonal Au7 in 1S 21P 41D 1 lacks the 1P occupied superatomic orbital which is distributed out of the structural plane. Different from the nearly degenerated five occupied 1D orbitals in Au13, Au35 in 1S 21P 61D 101F 101G 61H 1 shows energy separations over 4.0 eV between split 1D regions and 1F regions according to the preference of tubular geometry to different orbital morphologies. The structural reliance of the electronic structure revealed by these typical building blocks might be informative for bottom-up design and fabrication of nanoscale devices based on a gold nanostructure and contributes to the variety and operability of nanoscale materials.

  9. SENSITIVITY ANALYSIS OF BUILDING STRUCTURES WITHIN THE SCOPE OF ENERGY, ENVIRONMENT AND INVESTMENT

    Directory of Open Access Journals (Sweden)

    František Kulhánek

    2015-10-01

    Full Text Available The primary objective of this paper is to prove the feasibility of sensitivity analysis with dominant weight method for structure parts of envelope of buildings inclusive of energy; ecological and financial assessments, and determination of different designs for same structural part via multi-criteria assessment with theoretical example designs ancillary. Multi-criteria assessment (MCA of different structural designs or in other word alternatives aims to find the best available alternative. The application of sensitivity analysis technique in this paper bases on dominant weighting method. In this research, to choose the best thermal insulation design in the case of that more than one projection, simultaneously, criteria of total thickness (T; heat transfer coefficient (U through the cross section; global warming potential (GWP; acid produce (AP; primary energy content (PEI non renewable and cost per m2 (C are investigated for all designs via sensitivity analysis. Three different designs for external wall (over soil which are convenient with regard to globally suggested energy features for passive house design are investigated through the mentioned six projections. By creating a given set of scenarios; depending upon the importance of each criterion, sensitivity analysis is distributed. As conclusion, uncertainty in the output of model is attributed to different sources in the model input. In this manner, determination of the best available design is achieved. The original outlook and the outlook afterwards the sensitivity analysis are visualized, that enables easily to choose the optimum design within the scope of verified components.

  10. Modal Parameters Estimation of Building Structures from Vibration Test Data Using Observability Measurement

    Directory of Open Access Journals (Sweden)

    Jae-Seung Hwang

    2015-01-01

    Full Text Available The load distribution to each mode of a structure under seismic loading depends on the modal participation factors and mode shapes and thus the exact estimation of modal participation factors and mode shapes is essential to analyze the seismic response of a structure. In this study, an identification procedure for modal participation factors and mode shapes from a vibration test is proposed. The modal participation factors and mode shapes are obtained from the relationship between observability matrices realized from the system identification. Using the observability matrices, it is possible to transform an arbitrarily identified state space model obtained from the experimental data into a state space model which is defined in a domain with physical meaning. Then, the modal participation factor can be estimated based on the transformation matrix between two state space models. The numerical simulation is performed to evaluate the proposed procedure, and the results show that the modal participation factor and mode shapes are estimated from the structural responses accurately. The procedure is also applied to the experimental data obtained from the shaking table test of a three-story shear building model.

  11. Uncertainty quantification in structural health monitoring: Applications on cultural heritage buildings

    Science.gov (United States)

    Lorenzoni, Filippo; Casarin, Filippo; Caldon, Mauro; Islami, Kleidi; Modena, Claudio

    2016-01-01

    In the last decades the need for an effective seismic protection and vulnerability reduction of cultural heritage buildings and sites determined a growing interest in structural health monitoring (SHM) as a knowledge-based assessment tool to quantify and reduce uncertainties regarding their structural performance. Monitoring can be successfully implemented in some cases as an alternative to interventions or to control the medium- and long-term effectiveness of already applied strengthening solutions. The research group at the University of Padua, in collaboration with public administrations, has recently installed several SHM systems on heritage structures. The paper reports the application of monitoring strategies implemented to avoid (or at least minimize) the execution of strengthening interventions/repairs and control the response as long as a clear worsening or damaging process is detected. Two emblematic case studies are presented and discussed: the Roman Amphitheatre (Arena) of Verona and the Conegliano Cathedral. Both are excellent examples of on-going monitoring activities, performed through static and dynamic approaches in combination with automated procedures to extract meaningful structural features from collected data. In parallel to the application of innovative monitoring techniques, statistical models and data processing algorithms have been developed and applied in order to reduce uncertainties and exploit monitoring results for an effective assessment and protection of historical constructions. Processing software for SHM was implemented to perform the continuous real time treatment of static data and the identification of modal parameters based on the structural response to ambient vibrations. Statistical models were also developed to filter out the environmental effects and thermal cycles from the extracted features.

  12. Gap between technically accurate information and socially appropriate information for structural health monitoring system installed into tall buildings

    Science.gov (United States)

    Mita, Akira

    2016-04-01

    The importance of the structural health monitoring system for tall buildings is now widely recognized by at least structural engineers and managers at large real estate companies to ensure the structural safety immediately after a large earthquake and appeal the quantitative safety of buildings to potential tenants. Some leading real estate companies decided to install the system into all tall buildings. Considering this tendency, a pilot project for the west area of Shinjuku Station supported by the Japan Science and Technology Agency was started by the author team to explore a possibility of using the system to provide safe spaces for commuters and residents. The system was installed into six tall buildings. From our experience, it turned out that viewing only from technological aspects was not sufficient for the system to be accepted and to be really useful. Safe spaces require not only the structural safety but also the soundness of key functions of the building. We need help from social scientists, medical doctors, city planners etc. to further improve the integrity of the system.

  13. Chinese wood frame buildings and the changing dimensions of their structural components in different time periods

    Directory of Open Access Journals (Sweden)

    Nujaba Binte Kabir

    2012-06-01

    Full Text Available The Features of the Chinese wood frame buildings are same in character from dynasty to dynasty. The study concentrates on 9 Chinese wood frame buildings from Tang to Yuan dynasty and tries to relate these buildings with the text described in a building manual book published in Song dynasty Yingzao fashi. The features of some buildings match with the text described in the book some do not. But on the other hand Liang Sicheng, scholar of Chinese architecture in his book claimed that Chinese wood frame architecture has a unique system of characteristics (Liang, 1984. The system of wood frame Chinese architecture did not change but the proportion of the features has changed in different dynasty. The aim of the paper is to compare the features of the buildings those have been studied according to Yingzao fashi with Liang's observation on the change of building style in different periods.

  14. EVALUATION OF THE DURABILITY OF THE STRUCTURAL CONCRETE OF REACTOR BUILDINGS AT SRS

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, A.; Reigel, M.

    2011-02-28

    The Department of Energy (DOE) intends to close 100-150 facilities in the DOE complex using an in situ decommissioning (ISD) strategy that calls for grouting the below-grade interior volume of the structure and leaving the above-grade interior open or demolishing it and disposing of it in the slit trenches in E Area. These closures are expected to persist and remain stable for centuries, but there are neither facility-specific monitoring approaches nor studies on the rate of deterioration of the materials used in the original construction or on the ISD components added during closure (caps, sloped roofs, etc). This report will focus on the evaluation of the actual aging/degradation of the materials of construction used in the ISD structures at Savannah River Site (SRS) above grade, specifically P & R reactor buildings. Concrete blocks (six 2 to 5 ton blocks) removed from the outer wall of the P Reactor Building were turned over to SRNL as the first source for concrete cores. Larger cores were received as a result of grouting activities in P and R reactor facilities. The cores were sectioned and evaluated using microscopy, x-ray diffraction (XRD), ion chromatography (IC) and thermal analysis. Scanning electron microscopy shows that the aggregate and cement phases present in the concrete are consistent with the mix design and no degradation mechanisms are evident at the aggregate-cement interfaces. Samples of the cores were digested and analyzed for chloride ingress as well as sulfate attack. The concentrations of chloride and sulfate ions did not exceed the limits of the mix design and there is no indication of any degradation due to these mechanisms. Thermal analysis on samples taken along the longitudinal axis of the cores show that there is a 1 inch carbonation layer (i.e., no portlandite) present in the interior wall of the reactor building and a negligible carbonation layer in the exterior wall. A mixed layer of carbonate and portlandite extends deeper into the

  15. Influence of soil–structure interaction on seismic collapse resistance of super-tall buildings

    Directory of Open Access Journals (Sweden)

    Mengke Li

    2014-10-01

    Full Text Available Numerous field tests indicate that the soil–structure interaction (SSI has a significant impact on the dynamic characteristics of super-tall buildings, which may lead to unexpected structural seismic responses and/or failure. Taking the Shanghai Tower with a total height of 632 m as the research object, the substructure approach is used to simulate the SSI effect on the seismic responses of Shanghai Tower. The refined finite element (FE model of the superstructure of Shanghai Tower and the simplified analytical model of the foundation and adjacent soil are established. Subsequently, the collapse process of Shanghai Tower taking into account the SSI is predicted, as well as its final collapse mechanism. The influences of the SSI on the collapse resistance capacity and failure sequences are discussed. The results indicate that, when considering the SSI, the fundamental period of Shanghai Tower has been extended significantly, and the collapse margin ratio has been improved, with a corresponding decrease of the seismic demand. In addition, the SSI has some impact on the failure sequences of Shanghai Tower subjected to extreme earthquakes, but a negligible impact on the final failure modes.

  16. 3D RECONSTRUCTION OF BUILDINGS WITH GABLED AND HIPPED STRUCTURES USING LIDAR DATA

    Directory of Open Access Journals (Sweden)

    H. Amini

    2014-10-01

    Full Text Available Buildings are the most important objects in urban areas. Thus, building detection using photogrammetry and remote sensing data as well as 3D model of buildings are very useful for many applications such as mobile navigation, tourism, and disaster management. In this paper, an approach has been proposed for detecting buildings by LiDAR data and aerial images, as well as reconstructing 3D model of buildings. In this regard, firstly, building detection carried out by utilizing a Supper Vector Machine (SVM as a supervise method. The supervise methods need training data that could be collected from some features. Hence, LiDAR data and aerial images were utilized to produce some features. The features were selected by considering their abilities for separating buildings from other objects. The evaluation results of building detection showed high accuracy and precision of the utilized approach. The detected buildings were labeled in order to reconstruct buildings, individually. Then the planes of each building were separated and adjacent planes were recognized to reduce the calculation volume and to increase the accuracy. Subsequently, the bottom planes of each building were detected in order to compute the corners of hipped roofs using intersection of three adjacent planes. Also, the corners of gabled roofs were computed by both calculating the intersection line of the adjacent planes and finding the intersection between the planes intersection line and their detected parcel. Finally, the coordinates of some nodes in building floor were computed and 3D model reconstruction was carried out. In order to evaluate the proposed method, 3D model of some buildings with different complexity level were generated. The evaluation results showed that the proposed method has reached credible performance.

  17. D Reconstruction of Buildings with Gabled and Hipped Structures Using LIDAR Data

    Science.gov (United States)

    Amini, H.; Pahlavani, P.; Karimi, R.

    2014-10-01

    Buildings are the most important objects in urban areas. Thus, building detection using photogrammetry and remote sensing data as well as 3D model of buildings are very useful for many applications such as mobile navigation, tourism, and disaster management. In this paper, an approach has been proposed for detecting buildings by LiDAR data and aerial images, as well as reconstructing 3D model of buildings. In this regard, firstly, building detection carried out by utilizing a Supper Vector Machine (SVM) as a supervise method. The supervise methods need training data that could be collected from some features. Hence, LiDAR data and aerial images were utilized to produce some features. The features were selected by considering their abilities for separating buildings from other objects. The evaluation results of building detection showed high accuracy and precision of the utilized approach. The detected buildings were labeled in order to reconstruct buildings, individually. Then the planes of each building were separated and adjacent planes were recognized to reduce the calculation volume and to increase the accuracy. Subsequently, the bottom planes of each building were detected in order to compute the corners of hipped roofs using intersection of three adjacent planes. Also, the corners of gabled roofs were computed by both calculating the intersection line of the adjacent planes and finding the intersection between the planes intersection line and their detected parcel. Finally, the coordinates of some nodes in building floor were computed and 3D model reconstruction was carried out. In order to evaluate the proposed method, 3D model of some buildings with different complexity level were generated. The evaluation results showed that the proposed method has reached credible performance.

  18. 应用超常介质设计柱形隐形容器%Design Column Cloak Using Metamaterial

    Institute of Scientific and Technical Information of China (English)

    马越界; 黄建平; 孙文波; 刘德全

    2012-01-01

    Melamaterial, a kind of artificial material composed by nanometer units, can be controlled permittivity and permeability at the same time. Taking advantage of this finding, we can adjust the transmission of light We used the approach of transformation optics and calculated out the permittivity and permeability of Metamaterial cloak in the condition of cylindrical and elliptical cylinder, to make sure the light along the specific trajectory and spread around the cloak, then outgoing along the direction of the incident radiatioa In this way, the information inside the cloak can not be divulged.%超常介质是一种纳米尺度的人工复合材料,可以同时设定材料的介电常数和磁导率.利用超常介质的这一特性,能够自由地调整光的传播路径.在此基础上,应用坐标转换的方法,计算出圆柱形和椭圆柱形的介电常数和磁导率分布.让光在介质内沿着特定的轨迹传播,绕过包围的空腔,沿入射的方向出射,从而实现圆柱和椭圆柱形状的隐形.

  19. The role of polar, lamdba (Λ)-shaped building units in noncentrosymmetric inorganic structures.

    Science.gov (United States)

    Donakowski, Martin D; Gautier, Romain; Yeon, Jeongho; Moore, Donald T; Nino, Juan C; Halasyamani, P Shiv; Poeppelmeier, Kenneth R

    2012-05-01

    A methodology for the design of polar, inorganic structures is demonstrated here with the packing of lambda (Λ)-shaped basic building units (BBUs). Noncentrosymmetric (NCS) solids with interesting physical properties can be created with BBUs that lack an inversion center and are likely to pack into a polar configuration; previous methods to construct these solids have used NCS octahedra as BBUs. Using this methodology to synthesize NCS solids, one must increase the coordination of the NCS octahedra with maintenance of the noncentrosymmetry of the bulk. The first step in this progression from an NCS octahedron to an inorganic NCS solid is the formation of a bimetallic BBU. This step is exemplified with the compound CuVOF(4)(H(2)O)(7): this compound, presented here, crystallizes in an NCS structure with ordered, isolated [Cu(H(2)O)(5)](2+) cations and [VOF(4)(H(2)O)](2-) anions into Λ-shaped, bimetallic BBUs to form CuVOF(4)(H(2)O)(6)·H(2)O, owing to the Jahn-Teller distortion of Cu(2+). Conversely, the centrosymmetric heterotypes with the same formula MVOF(4)(H(2)O)(7) (M(II) = Co, Ni, and Zn) exhibit ordered, isolated [VOF(4)(H(2)O)](2-) and [M(H(2)O)(6)](2+) ionic species in a hydrogen bond network. CuVOF(4)(H(2)O)(7) exhibits a net polar moment while the heterotypes do not; this demonstrates that Λ-shaped BBUs give a greater probability for and, in this case, lead to NCS structures.

  20. Evaluation of Seismic Performance and Effectiveness of Multiple Slim-Type Damper System for Seismic Response Control of Building Structures

    Directory of Open Access Journals (Sweden)

    David Kim

    2014-01-01

    Full Text Available This paper presents the evaluation of seismic performance and cost-effectiveness of a multiple slim-type damper system developed for the vibration control of earthquake excited buildings. The multiple slim-type damper (MSD that consists of several small slim-type dampers and linkage units can control damping capacity easily by changing the number of small dampers. To evaluate the performance of the MSD, dynamic loading tests are performed with three slim-type dampers manufactured at a real scale. Numerical simulations are also carried out by nonlinear time history analysis with a ten-story earthquake excited building structure. The seismic performance and cost-effectiveness of the MSD system are investigated according to the various installation configurations of the MSD system. From the results of numerical simulation and cost-effectiveness evaluation, it is shown that combinations of the MSD systems can effectively improve the seismic performance of earthquake excited building structures.

  1. Seismic soil structure interaction analysis for asymmetrical buildings supported on piled raft for the 2015 Nepal earthquake

    Science.gov (United States)

    Badry, Pallavi; Satyam, Neelima

    2017-01-01

    Seismic damage surveys and analyses conducted on modes of failure of structures during past earthquakes observed that the asymmetrical buildings show the most vulnerable effect throughout the course of failures (Wegner et al., 2009). Thus, all asymmetrical buildings significantly fails during the shaking events and it is really needed to focus on the accurate analysis of the building, including all possible accuracy in the analysis. Apart from superstructure geometry, the soil behavior during earthquake shaking plays a pivotal role in the building collapse (Chopra, 2012). Fixed base analysis where the soil is considered to be infinitely rigid cannot simulate the actual scenario of wave propagation during earthquakes and wave transfer mechanism in the superstructure (Wolf, 1985). This can be well explained in the soil structure interaction analysis, where the ground movement and structural movement can be considered with the equal rigor. In the present study the object oriented program has been developed in C++ to model the SSI system using the finite element methodology. In this attempt the seismic soil structure interaction analysis has been carried out for T, L and C types piled raft supported buildings in the recent 25th April 2015 Nepal earthquake (M = 7.8). The soil properties have been considered with the appropriate soil data from the Katmandu valley region. The effect of asymmetry of the building on the responses of the superstructure is compared with the author's research work. It has been studied/observed that the shape or geometry of the superstructure governs the response of the superstructure subjected to the same earthquake load.

  2. Structural response of nuclear containment shield buildings with unanticipated construction openings

    Science.gov (United States)

    Mac Namara, Sinead Caitriona

    As Nuclear Power Plants age many require steam generator replacement. There is a nickel alloy in the steam generator tubes that is susceptible to stress cracking and although these cracks can be sealed the generator becomes uneconomical without 10%-15% of the tubes. The steam generator in a typical nuclear power plant is housed in the containment structure next to the reactor. The equipment hatch is not big enough to facilitate steam generator replacement, thus construction openings in the dome of the containment structure are required. To date the structural consequences of construction openings in the dome have not been examined. This thesis examines the effects of such openings. The prototype concrete dome is made up of a 2 ft thick dome atop 3 ft thick and 170 ft high cylindrical walls (radius 65.5 ft) with a tension ring 15 ft high and 8 ft thick in between. The dome of the building is cast in two layers; a lower 9 inch layer that serves as the formwork for an upper 15 inch layer. The weight of the dome is carried in axial compression along the hoops and meridians of the dome. The first finite element model uses shell elements and considers two limiting load cases; where the two layers act as one, and where the lower layer carries the weight of both. The openings interrupt the hoops and meridians and the weight of the dome must be redistributed around the openings. Without openings, the stresses due to dead load in the structure are very low when compared to the material strength. The impact of the openings is increased compression stresses near the opening. The maximum stresses are approximately four times larger than in the original structure. These results are confirmed by the second model which is made from layers of solid elements. This model shows a significant difference between the compression on the top surface of the dome, in the affected areas, and that on the bottom surface, leading to shear stresses. These shear stresses are largest around the

  3. Influence of dynamic soil-structure interaction on building response to ground vibration

    DEFF Research Database (Denmark)

    Andersen, Lars Vabbersgaard

    2014-01-01

    Vibration from traffic and pile driving are an increasing problem in densely populated areas. To assess vibration levels in new or existing buildings near construction sites, roads or railways in the design phase, valid models for prediction of wave transmission via the ground and into a building...... must be used. In this regard it is often assumed that a no significant back coupling from the building to the ground exists. Thus, a model with free-field vibrations from the ground provides input at the base of the building model. The aim of the present paper is to examine whether—and to which extent...

  4. Energy Efficiency and Sustainability of Different Building Structures in Latvian Climate

    Science.gov (United States)

    Jakovičs, A.; Gendelis, S.; Bandeniece, L.

    2015-11-01

    Five experimental test buildings have been built in Riga, Latvia. They are identical except external walls for which different mainly regional building materials are used. Calculated U-values of the other walls, floor and ceiling are the same for each test building. Initial moisture influences the relative humidity of indoor air, which can be higher in the initial time period; as a result, heat transmittances are also very different and cause different heating/cooling energy consumption. Overheating risk in summer exists for test buildings with the smallest thermal inertia. Both summer and heating seasons have been analysed and differences between five test houses have been discussed in details.

  5. Building on the Existing Structures; an Outreach Strategy for Improving the Capacity for Education in the Inner Cities.

    Science.gov (United States)

    Wang, Margaret C.; Iglesias, Aquiles

    1996-01-01

    Describes design and implementation of the outreach and dissemination approach used by the National Center on Education in the Inner Cities, with emphases on building on existing structures for information dissemination, training, and technical support for research utilization. Application of the Model of Outreach and Utilization was guided by two…

  6. To Problem Pertaining to Calculation of Resistance to Heat Transfer in Modern Structures of Building External Walls

    Directory of Open Access Journals (Sweden)

    L. V. Nesterov

    2007-01-01

    Full Text Available The paper presents a new methodology for determination of resistance to heat transfer of building external walls with the introduction of heat engineering uniformity factors obtained on the basis of calculating two- and three-dimensional temperature pattern. The methodology makes it possible to take into account influence of joints, connections with adjoining structures and jambs of external walls.

  7. Formation and erosion of biogeomorphological structures: A model study on the tube-building polychaete Lanice conchilega

    NARCIS (Netherlands)

    Borsje, B.W.; Bouma, T.J.; Rabaut, M.; Herman, P.M.J.; Hulscher, S.J.M.H.

    2014-01-01

    We study how organism traits and population densities of ecosystem engineering species, in combination with environmental factors, affect the formation and erosion rates of biogeomorphological structures, and focus on the widely distributed marine tube-building polychaete Lanice conchilega, which li

  8. On development status for steel structure residential buildings%谈钢结构住宅发展现状

    Institute of Scientific and Technical Information of China (English)

    杨永兴

    2012-01-01

    The paper sums up the advantages of the steel structure residential buildings,introduces the components,the classification and the features of the light-steel structure residential building system,analyzes and researches the development status for the light-steel structure residential buildings,and provides some suggestions for the problems in the development process of the steel structure residential buildings based on the previous views,so as to direct the practice.%总结了钢结构住宅的优越性,着重介绍了轻钢结构住宅体系的组成、分类和特点,分析研究了轻钢结构住宅的发展现状,在此基础上对目前钢结构住宅发展过程中存在的问题给出了一些建议,以期指导实践。

  9. On the effectiveness of smart technologies in the seismic protection of existing buildings Part II: Reinforced concrete structures

    Science.gov (United States)

    Mandara, A.; Ramundo, F.; Spina, G.

    2008-07-01

    The second part of a study concerning innovative intervention techniques for seismic protection of existing buildings is presented in this paper. The case of an existing framed r.c. structure, not designed for horizontal forces and extremely vulnerable to seismic action, is analyzed both in terms of maximum response reduction and energy dissipation. The proposed intervention approach, based on steel braces linked to the existing structure by passive or smart devices comes out appropriate and effective in the case of this type of buildings. The adopted control strategy produces a significant reducing effect on the elastic strain energy transmitted by the external perturbation to the structure, which is itself a fundamental safeguard aspect. The results prove the significantly improved capability of the system to dissipate input energy without structural damage, regardless of the specific seismic input.

  10. Structural Performance Assessment Based on Statistical and Wavelet Analysis of Acceleration Measurements of a Building during an Earthquake

    Directory of Open Access Journals (Sweden)

    Mosbeh R. Kaloop

    2016-01-01

    Full Text Available This study introduces the analysis of structural health monitoring (SHM system based on acceleration measurements during an earthquake. The SHM system is applied to assess the performance investigation of the administration building in Seoul National University of Education, South Korea. The statistical and wavelet analysis methods are applied to investigate and assess the performance of the building during an earthquake shaking which took place on March 31, 2014. The results indicate that (1 the acceleration, displacement, and torsional responses of the roof recording point on the top floor of the building are more dominant in the X direction; (2 the rotation of the building has occurred at the base recording point; (3 95% of the energy content of the building response is shown in the dominant frequency range (6.25–25 Hz; (4 the wavelet spectrum illustrates that the roof vibration is more obvious and dominant during the shaking; and (5 the wavelet spectrum reveals the elasticity responses of the structure during the earthquake shaking.

  11. Mechanism and bounding of earthquake energy input to building structure on surface ground subjected to engineering bedrock motion

    OpenAIRE

    Kojima, K; Sakaguchi, K; Takewaki, I.

    2015-01-01

    The mechanism of earthquake energy input to building structures is clarified by considering the surface ground amplification and soil–structure interaction. The earthquake input energies to superstructures, soil–foundation systems and total swaying–rocking system are obtained by taking the corresponding appropriate free bodies into account and defining the energy transfer functions. It has been made clear that, when the ground surface motion is white, the input energy to the swaying–rocking m...

  12. Building disc structure and galaxy properties through angular momentum: the DARK SAGE semi-analytic model

    Science.gov (United States)

    Stevens, Adam R. H.; Croton, Darren J.; Mutch, Simon J.

    2016-09-01

    We present the new semi-analytic model of galaxy evolution, DARK SAGE, a heavily modified version of the publicly available SAGE code. The model is designed for detailed evolution of galactic discs. We evolve discs in a series of annuli with fixed specific angular momentum, which allows us to make predictions for the radial and angular-momentum structure of galaxies. Most physical processes, including all channels of star formation and associated feedback, are performed in these annuli. We present the surface density profiles of our model spiral galaxies, both as a function of radius and specific angular momentum, and find that the discs naturally build a pseudo-bulge-like component. Our main results are focused on predictions relating to the integrated mass-specific angular momentum relation of stellar discs. The model produces a distinct sequence between these properties in remarkable agreement with recent observational literature. We investigate the impact Toomre disc instabilities have on shaping this sequence and find they are crucial for regulating both the mass and spin of discs. Without instabilities, high-mass discs would be systematically deficient in specific angular momentum by a factor of ˜2.5, with increased scatter. Instabilities also appear to drive the direction in which the mass-spin sequence of spiral galaxy discs evolves. With them, we find galaxies of fixed mass have higher specific angular momentum at later epochs.

  13. Building large collections of Chinese and English medical terms from semi-structured and encyclopedia websites.

    Science.gov (United States)

    Xu, Yan; Wang, Yining; Sun, Jian-Tao; Zhang, Jianwen; Tsujii, Junichi; Chang, Eric

    2013-01-01

    To build large collections of medical terms from semi-structured information sources (e.g. tables, lists, etc.) and encyclopedia sites on the web. The terms are classified into the three semantic categories, Medical Problems, Medications, and Medical Tests, which were used in i2b2 challenge tasks. We developed two systems, one for Chinese and another for English terms. The two systems share the same methodology and use the same software with minimum language dependent parts. We produced large collections of terms by exploiting billions of semi-structured information sources and encyclopedia sites on the Web. The standard performance metric of recall (R) is extended to three different types of Recall to take the surface variability of terms into consideration. They are Surface Recall (R(S)), Object Recall (R(O)), and Surface Head recall (R(H)). We use two test sets for Chinese. For English, we use a collection of terms in the 2010 i2b2 text. Two collections of terms, one for English and the other for Chinese, have been created. The terms in these collections are classified as either of Medical Problems, Medications, or Medical Tests in the i2b2 challenge tasks. The English collection contains 49,249 (Problems), 89,591 (Medications) and 25,107 (Tests) terms, while the Chinese one contains 66,780 (Problems), 101,025 (Medications), and 15,032 (Tests) terms. The proposed method of constructing a large collection of medical terms is both efficient and effective, and, most of all, independent of language. The collections will be made publicly available.

  14. Building large collections of Chinese and English medical terms from semi-structured and encyclopedia websites.

    Directory of Open Access Journals (Sweden)

    Yan Xu

    Full Text Available To build large collections of medical terms from semi-structured information sources (e.g. tables, lists, etc. and encyclopedia sites on the web. The terms are classified into the three semantic categories, Medical Problems, Medications, and Medical Tests, which were used in i2b2 challenge tasks. We developed two systems, one for Chinese and another for English terms. The two systems share the same methodology and use the same software with minimum language dependent parts. We produced large collections of terms by exploiting billions of semi-structured information sources and encyclopedia sites on the Web. The standard performance metric of recall (R is extended to three different types of Recall to take the surface variability of terms into consideration. They are Surface Recall (R(S, Object Recall (R(O, and Surface Head recall (R(H. We use two test sets for Chinese. For English, we use a collection of terms in the 2010 i2b2 text. Two collections of terms, one for English and the other for Chinese, have been created. The terms in these collections are classified as either of Medical Problems, Medications, or Medical Tests in the i2b2 challenge tasks. The English collection contains 49,249 (Problems, 89,591 (Medications and 25,107 (Tests terms, while the Chinese one contains 66,780 (Problems, 101,025 (Medications, and 15,032 (Tests terms. The proposed method of constructing a large collection of medical terms is both efficient and effective, and, most of all, independent of language. The collections will be made publicly available.

  15. European database on indoor air pollution sources in buildings: Current status of database structure and software

    NARCIS (Netherlands)

    Molina, J.L.; Clausen, G.H.; Saarela, K.; Plokker, W.; Bluyssen, P.M.; Bishop, W.; Oliveira Fernandes, E. de

    1996-01-01

    the European Joule II Project European Data Base for Indoor Air Pollution Sources in Buildings. The aim of the project is to produce a tool which would be used by designers to take into account the actual pollution of the air from the building elements and ventilation and air conditioning system com

  16. Structural damages observed in state buildings after Simav/Turkey earthquake occurred on 19 May 2011

    Directory of Open Access Journals (Sweden)

    Y. S. Tama

    2012-08-01

    Full Text Available Different levels of damages occurred in state buildings, especially in educational facilities, during the Simav earthquake (ML=5.7 on 19 May 2011. A site survey was carried out in the area after the earthquake, where six state buildings were examined in detail. The results of the survey showed that main reasons for the formation of damages in these buildings are the use of low strength concrete, insufficient reinforcement, inappropriate detailing, and low-quality workmanship. The investigated buildings were also evaluated by P25-rapid assessment method. The method demonstrates that two of the buildings in question are in "high risk band"; the other two fall into "detailed evaluation band", and the rest are in the "low risk band". This figure also matches with the damages observed in the site survey.

  17. Effects of salinity build-up on the performance and bacterial community structure of a membrane bioreactor.

    Science.gov (United States)

    Luo, Wenhai; Phan, Hop V; Hai, Faisal I; Price, William E; Guo, Wenshan; Ngo, Hao H; Yamamoto, Kazuo; Nghiem, Long D

    2016-01-01

    This study investigated the effects of salinity increase on bacterial community structure in a membrane bioreactor (MBR) for wastewater treatment. The influent salt loading was increased gradually to simulate salinity build-up in the bioreactor during the operation of a high retention-membrane bioreactor (HR-MBR). Bacterial community diversity and structure were analyzed using 454 pyrosequencing of 16S rRNA genes of MBR mixed liquor samples. Results show that salinity increase reduced biological performance but did not affect microbial diversity in the bioreactor. Unweighted UniFrac and taxonomic analyses were conducted to relate the reduced biological performance to the change of bacterial community structure. In response to the elevated salinity condition, the succession of halophobic bacteria by halotolerant/halophilic microbes occurred and thereby the biological performance of MBR was recovered. These results suggest that salinity build-up during HR-MBR operation could be managed by allowing for the proliferation of halotolerant/halophilic bacteria.

  18. Role of on-board discharge in shock wave drag reduction and plasma cloaking

    Institute of Scientific and Technical Information of China (English)

    Qiu Xiao-Ming; Tang De-Li; Sun Ai-Ping; Liu Wan-Dong; Zeng Xue-Jun

    2007-01-01

    In the present paper, a physical model is proposed for reducing the problem of the drag reduction of an attached bow shock around the nose of a high-speed vehicle with on-board discharge, to the problem of a balance between the magnetic pressure and gas pressure of plane shock of a partially ionized gas consisting of the environmental gas around the nose of the vehicle and the on-board discharge-produced plasma. The relation between the shock strength and the discharge-induced magnetic pressure is studied by means of a set of one-fluid, hydromagnetic equations reformed for the present purpose, where the discharge-induced magnetic field consists of the electron current (produced by the discharge)-induced magnetic field and the partially ionized gas flow-induced one. A formula for the relation between the above parameters is derived. It shows that the discharge-induced magnetic pressure can minimize the shock strength,successfully explaining the two recent experimental observations on attached bow shock mitigation and elimination in a supersonic flow during on-board discharge [Phys. Plasmas 9 (2002) 721 and Phys. Plasmas 7 (2000) 1345]. In addition,the formula implies that the shock elimination leaves room for a layer of higher-density plasma rampart moving around the nose of the vehicle, being favourable to the plasma radar cloaking of the vehicle. The reason for it is expounded.

  19. Submentalizing or Mentalizing in a Level 1 Perspective-Taking Task: A Cloak and Goggles Test

    Science.gov (United States)

    2016-01-01

    It has been proposed that humans possess an automatic system to represent mental states (‘implicit mentalizing’). The existence of an implicit mentalizing system has generated considerable debate however, centered on the ability of various experimental paradigms to demonstrate unambiguously such mentalizing. Evidence for implicit mentalizing has previously been provided by the ‘dot perspective task,’ where participants are slower to verify the number of dots they can see when an avatar can see a different number of dots. However, recent evidence challenged a mentalizing interpretation of this effect by showing it was unaltered when the avatar was replaced with an inanimate arrow stimulus. Here we present an extension of the dot perspective task using an invisibility cloaking device to render the dots invisible on certain trials. This paradigm is capable of providing unambiguous evidence of automatic mentalizing, but no such evidence was found. Two further well-powered experiments used opaque and transparent goggles to manipulate visibility but found no evidence of automatic mentalizing, nor of individual differences in empathy or perspective-taking predicting performance, contradicting previous studies using the same design. The results cast doubt on the existence of an implicit mentalizing system, suggesting that previous effects were due to domain-general processes. PMID:27893269

  20. Mobile agent-enabled framework for structuring and building distributed systems on the internet

    Institute of Scientific and Technical Information of China (English)

    CAO Jiannong; ZHOU Jingyang; ZHU Weiwei; LI Xuhui

    2006-01-01

    Mobile agent has shown its promise as a powerful means to complement and enhance existing technology in various application areas. In particular, existing work has demonstrated that MA can simplify the development and improve the performance of certain classes of distributed applications, especially for those running on a wide-area, heterogeneous, and dynamic networking environment like the Internet. In our previous work, we extended the application of MA to the design of distributed control functions, which require the maintenance of logical relationship among and/or coordination of processing entities in a distributed system. A novel framework is presented for structuring and building distributed systems, which use cooperating mobile agents as an aid to carry out coordination and cooperation tasks in distributed systems. The framework has been used for designing various distributed control functions such as load balancing and mutual exclusion in our previous work. In this paper, we use the framework to propose a novel approach to detecting deadlocks in distributed system by using mobile agents, which demonstrates the advantage of being adaptive and flexible of mobile agents. We first describe the MAEDD (Mobile Agent Enabled Deadlock Detection) scheme, in which mobile agents are dispatched to collect and analyze deadlock information distributed across the network sites and, based on the analysis, to detect and resolve deadlocks. Then the design of an adaptive hybrid algorithm derived from the framework is presented. The algorithm can dynamically adapt itself to the changes in system state by using different deadlock detection strategies. The performance of the proposed algorithm has been evaluated using simulations. The results show that the algorithm can outperform existing algorithms that use a fixed deadlock detection strategy.

  1. Development of a seismic design method based on response spectra for building structures

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xiyuan; YU Ruifang

    2007-01-01

    The assumption and problem of the mode-superposition response spectrum method in seismic design code is discussed based on a brief review of the development of the seismic design method for building structures. The scope of application for the classical damping theory is ana- lyzed and the necessity of the research on mode-superposition method for non-classical damping is presented. The pro- gresses on the mode superposition response spectrum theory are discussed. This includes: 1) the complex mode superposi- tion method (in real form) for the non-classically damped linear system and the general calculation formula for the application of code; 2) the complex complete quadratic com- bination (CCQC) method for the non-classically damped linear system, which is based on the same assumptions as in deducing the complete quadratic combination (CQC) method which is popularly used in seismic design codes of many countries; 3) the complex complete quadratic combination with three components (CCQC3) method, which is a general- ization of the CCQC method to the case of multi-components and multiple-support seismic excitations and deducing cor- responding method; 4) the approach for calculation of seismic response of the non-classically damped system with over- critical damping and the calculation method of seismic response for the linear system with multiple eigenvalues; 5) the time-dependent CCQC(t) algorithm considering non- stationary earthquake ground motion; 6) an applied and effec- tive method to solve the low order complex vector basis for the large linear non-classically damped system, which can be expediently used in practice to avoid the unknown errors coming from the forced uncoupling method; 7) bringing for- ward the concept of partial quadratic combination in order to reduce the calculation amount of CQC and CCQC methods, and studying the primary estimation-criterion. The reason- ability and applicable scope of these methods are also briefly discussed in this

  2. VIBRATION TESTING OF A SIXTEEN-STORIED BUILDING THAT HAS A PRECAST CONCRETE BOX STRUCTURE

    Directory of Open Access Journals (Sweden)

    Rumyantsev Anton Andreevich

    2012-10-01

    Full Text Available This article covers the problems of theoretical assessment of the seismic stability of a 16-storied building made of precast concrete box units by full-scale experimental testing through the employment of a powerful unbalance-type vibration machine. The authors provide the results of the experimental testing and scale them to assess the effects of an earthquake. The testing procedure that consists in the assessment of the seismic stability of buildings through employment of the vibration testing performed by a powerful vibration machine installed on the soil surface, have proven its high efficiency. As a result of the vibration testing, specific values of accelerations and shifts in terms of the building height and length were identified in lateral and longitudinal directions. The results of extrapolation of the seismic effect of the vibration testing onto the 9-grade seismic load scale have proven that the buildings of this type can be considered seismically stable.

  3. Assessment of Structural Resistance of building 4862 to Earthquake and Tornado Forces [SEC 1 and 2

    Energy Technology Data Exchange (ETDEWEB)

    METCALF, I.L.

    1999-12-06

    This report presents the results of work done for Hanford Engineering Laboratory under contract Y213-544-12662. LATA performed an assessment of building 4862 resistance to earthquake and tornado forces.

  4. Consideration of hazardous and especially hazardous hydrometeorological impacts in design of buildings and structures of nuclear power plants

    Directory of Open Access Journals (Sweden)

    Bryukhan Fedor

    2016-01-01

    Full Text Available External impacts of the hydrometeorological origin have a significant influence on the safety level of objects of use of atomic energy (OUAE, including nuclear power plants (NPP. Therefore, the existing NPP-related safety regulations demand to consider such impacts at all stages of the NPP life cycle. It is important to make decisions on considering or ignoring certain external impacts while designing NPP buildings and structures. The main criterion for such decisions is the probability of a non-project accident associated with the release of radionuclides into the environment when an extreme phenomena occurs. The aim of this study is to develop a concept for refinement regulatory requirements, considering hydrometeorological factors in organization of NPP engineering protection. Criteria for consideration of hazardous and especially hazardous hydrometeorological impacts for design of NPP buildings and structures were analyzed, and recommendations for refinement of regulatory requirements, considering hydrometeorological factors in organization of NPP engineering protection, were developed.

  5. Earthquake Shaking and Damage to Buildings: Recent evidence for severe ground shaking raises questions about the earthquake resistance of structures.

    Science.gov (United States)

    Page, R A; Joyner, W B; Blume, J A

    1975-08-22

    Ground shaking close to the causative fault of an earthquake is more intense than it was previously believed to be. This raises the possibility that large numbers of buildings and other structures are not sufficiently resistant for the intense levels of shaking that can occur close to the fault. Many structures were built before earthquake codes were adopted; others were built according to codes formulated when less was known about the intensity of near-fault shaking. Although many building types are more resistant than conventional design analyses imply, the margin of safety is difficult to quantify. Many modern structures, such as freeways, have not been subjected to and tested by near-fault shaking in major earthquakes (magnitude 7 or greater). Damage patterns in recent moderate-sized earthquakes occurring in or adjacent to urbanized areas (17), however, indicate that many structures, including some modern ones designed to meet earthquake code requirements, cannot withstand the severe shaking that can occur close to a fault. It is necessary to review the ground motion assumed and the methods utilized in the design of important existing structures and, if necessary, to strengthen or modify the use of structures that are found to be weak. New structures situated close to active faults should be designed on the basis of ground motion estimates greater than those used in the past. The ultimate balance between risk of earthquake losses and cost for both remedial strengthening and improved earthquake-resistant construction must be decided by the public. Scientists and engineers must inform the public about earthquake shaking and its effect on structures. The exposure to damage from seismic shaking is steadily increasing because of continuing urbanization and the increasing complexity of lifeline systems, such as power, water, transportation, and communication systems. In the near future we should expect additional painful examples of the damage potential of moderate

  6. Dynamic Responses Analysis of a Building Structure Subjected to Ground Shock from a Tunnel Explosion

    Institute of Scientific and Technical Information of China (English)

    TIAN Li; LI Zhongxian; HAO Hong

    2006-01-01

    Dynamic responses of a multi-storey building without or with a sliding base-isolation device for ground shock induced by an in-tunnel explosion are numerically analyzed.The effect of an adjacent tunnel in between the building and the explosion tunnel,which affects ground shock propagation,is considered in the analysis.Different modeling methods,such as the eight-node equal-parametric finite element and mass-lumped system,are used to establish the coupling model consisting of the two adjacent tunnels,the surrounding soil medium with the Lysmer viscous boundary condition,and the multi-storey building with or without the sliding base-isolation device.In numerical calculations,a continuous friction model,which is different from the traditional Coulomb friction model,is adopted to improve the computational efficiency and reduce the accumulated errors.Some example analyses are subsequently performed to study the response characteristics of the building and the sliding base-isolation device to ground shock.The effect of the adjacent tunnel in between the building and the explosion tunnel on the ground shock wave propagation is also investigated.The final conclusions based on the numerical results will provide some guidance in engineering practice.

  7. Energy efficiency of the Rural Wall multi-layer structure in low-rise building design

    Directory of Open Access Journals (Sweden)

    T.A. Golova

    2014-12-01

    Full Text Available This paper presents the study on energy efficiency of various wall design solutions and a new multi-layer wall design for low-rise construction as well as the results of television studies on multi-layer and single-layer envelopes. Indoor climate parameters for various wall design solutions are determined. The study reveals the optimal wall design solutions and specifies the theoretical assessment of their energy efficiency in compliance with Russia's national building code 23-02-2003. The paper presents calculations of building heat loss through the exterior building envelope, reduced resistance to heat transfer of walls and total heat loss of the building with the selected outer wall design during the heating season. Recommendations on the application of the new multi-layer wall design using local wall materials in the construction of energy-efficient low-rise buildings are developed. The recommendations include requirements for wall materials, thermal calculations, production guidelines, properties of layers in a multi-layer walls and physical and mechanical properties of wall layers.

  8. Predicting the Impact of Rock Blasting on Building Structures at Awunakrom in the Ahanta West District of Ghana

    Directory of Open Access Journals (Sweden)

    K.J. Bansah

    2014-07-01

    Full Text Available Blasting is an important process after drilling is completed in hard rock mining. It involves placing explosives in drill holes and detonating them to cause explosion. The energy released during this process fragments the rocks into sizes for desired end use. The detonation of these explosives may produce undesirable effects such as ground vibration which is capable of causing damage to building structures. It is therefore, necessary to conduct blast impact studies to determine potential impact of blast induced ground vibration prior to mining and establish remediation techniques. Blast impact study was conducted at Awunakrom in the Ahanta West District of Ghana. Building structures within the study area were mapped and characterized. A blast impact prediction model was also generated. Blast induced vibrations that may propagate from the Father Brown pit of Golden Star Wassa Limited using various instantaneous charges were determined. It was found that bench blasting at the Father Brown pit has a potential of causing damage to building structures within the Awunakrom community if the maximum instantaneous charge adopted at the southernmost periphery of the pit exceeds 30 kg. It was therefore, recommended that all bench blast conducted at the southern periphery of the Father Brown pit should adopt a maximum instantaneous charge of 30 kg to avert any potential blast damage. However, variable instantaneous charges of more than 30 kg can be adopted as the blast location moves towards the northern periphery.

  9. Architectural structure and environmental performance of the traditional buildings in Florina, NW Greece

    Energy Technology Data Exchange (ETDEWEB)

    Oikonomou, A. [Department of Architecture, University of Patras (Greece); Bougiatioti, F. [School of Architecture, National Technical University of Athens, 25, Iasonos Street, 166-71 Vouliagmeni, Athens (Greece)

    2011-03-15

    This paper presents various aspects, which characterise the traditional architecture in the town of Florina, north-western Greece, and can be related to bioclimatic and environmental architecture. The study is based on the documentation and the analysis of the architectural and bioclimatic aspects of a sample of forty (40) remaining houses of the 19th and the beginning of the 20th century. The analysis of the architectural aspects concerns the building typology, the form, the materials and the construction techniques, whereas the analysis of bioclimatic aspects involves the thermal behaviour of the building shell, the thermal and the visual comfort conditions. The aim of the study is to document and assess, both qualitatively and quantitatively, all the afore-mentioned aspects in order to draw conclusions concerning the principles, which characterised this architecture and can be integrated to the refurbishment of existing buildings or the design of new ones in traditional surroundings. (author)

  10. Connecting Structure of Steel Structure Building Component%钢结构建筑构件连接构造技术

    Institute of Scientific and Technical Information of China (English)

    贾立强

    2015-01-01

    钢材作为一种现代化的建筑材料,近年来得到了极大的发展。在钢结构建筑的应用和发展中,钢结构建筑构件连接构造技术占有十分重要的位置。通过对不同方面构件连接构造技术的研究,探讨了各种技术的优缺点和实际应用,以期更好地推动钢结构建筑的发展和进步。%As a kind of modern building materials, steel has been greatly developed in recent years. In the application and development of steel structure building, the connecting structure of steel structure construction technology is very important. Through the research on the construction technology of different aspects, the advantages and disadvantages of various techniques are discussed, and the practical application is discussed in order to promote the development and progress of steel structure building.

  11. Network Structure, Diversity, and Proactive Resilience Building: a Response to Tompkins and Adger

    Directory of Open Access Journals (Sweden)

    Ann Dale

    2005-06-01

    Full Text Available Although community social networks can build resilience, and thus, aid adaptation to unexpected environmental change (Tomkins and Adger 2004, not all social networks are created equal. Networks composed of a diversity of “bridging” links to a diverse web of resources and “bonding” links that build trust strengthen a community's ability to adapt to change, but networks composed only of “bonding” links can impose constraining social norms and foster group homophily, reducing resilience. Diversity fosters the resilience needed to adapt to unexpected change, and can also enlarge the ability to proactively make collective decisions that optimize future options.

  12. Prediction of the structural fire performance of buildings%建筑物结构火灾性能预测

    Institute of Scientific and Technical Information of China (English)

    Richard W. Bukowski; P.E. FSFPE

    2004-01-01

    回顾了建筑物结构火灾性能研究的历史,介绍了构件耐火试验和性能化防火的法则,介绍了研究方案和国际合作进度.%Look back on background for research of the structural fire performanre of buildings. Introduce fire endurance tests of the structure element and performence based fire prevention design regulations. Final, introduce organization of the project.

  13. Playing with structures at the nanoscale: designing catalysts by manipulation of clusters and nanocrystals as building blocks.

    Science.gov (United States)

    Cargnello, Matteo; Fornasiero, Paolo; Gorte, Raymond J

    2013-12-02

    The purpose of this Concept is to highlight some of the most recent and promising methods for the preparation of tailored catalysts by designing and preparing the component building blocks and by assembling them in a controlled fashion. We want to emphasize how rational design and synthesis of catalysts must be coupled to precise catalytic and structural characterization of the systems in an ideal feedback loop. New catalyst design and preparation techniques, dictated by information about the active sites that the specific application requires, are frequently available. The building blocks for developing these novel catalysts include colloidal methods for the preparation of uniform nanostructures, physical methods for rational assembly of the building blocks (Langmuir-Blodgett, liquid-air self-assembly), and development of rational interactions between the building blocks for enhanced activity of the assemblies. These methods, which apply techniques normally used in other fields of nanotechnology to catalysis, offer exciting opportunities to help improve currently available catalytic systems in terms of activity, stability and selectivity.

  14. Experimental investigations of building structure with a superelastic shape memory alloy friction damper subject to seismic loads

    Science.gov (United States)

    Qian, Hui; Li, Hongnan; Song, Gangbing

    2016-12-01

    With the goal to assess its effectiveness in structural vibration suppression under strong seismic excitations, this paper experimentally investigates shaking table tests of a new superelastic shape memory alloy friction damper (SSMAFD). The damper consists of pre-tensioned superelastic shape memory alloy (SMA) wires and friction devices. The main function of SMA wires is to provide re-centering capacity, while the integrated friction devices provide the most energy dissipation. With the inherent damping property, the superelastic SMA wires also provide energy dissipation. In the shaking table tests, a scaled-down building structure were used as the subject for vibration control and several representative seismic signals as well as white noise motions were used as the inputs. Comparative studies of dynamic behaviors, i.e. story displacements, interstory drifts and story accelerations, of the structural model with and without SSMAFD under seismic loading were performed. The experimental results demonstrated that the SSMAFD was effective in suppressing the dynamic response of the building structure subjected to strong earthquakes by dissipating a large portion of the energy. In addition, with the re-centering capacity of the proposed damper, the structure was able to undergo strong earthquakes without remarkable residual drift under different seismic loads.

  15. Extended structure design with simple molybdenum oxide building blocks and urea as a directing agent

    NARCIS (Netherlands)

    Veen, S.J.; Roy, S.; Filinchuk, Y.; Chernyshov, D.; Petukhov, A.V.; Versluijs-Helder, M.; Broersma, A.; Soulimani, F.; Visser, T.; Kegel, W.K.

    2008-01-01

    We report here a simple one-pot directed synthesis of an oxomolybdate urea composite in which elementary molybdenum oxide building blocks are linked together with the aid of urea. This type of directed material design resulted in large rod-like crystals of an inorganic-organic hybrid extended struct

  16. The impact of sensor errors and building structures on particle filter-based inertial positioning

    DEFF Research Database (Denmark)

    Toftkjær, Thomas; Kjærgaard, Mikkel Baun

    2012-01-01

    Positioning systems that do not depend on in-building infrastructures are critical for enabling a range of applications within pervasive computing. Particle filter-based inertial positioning promises infrastructure-less positioning, but previous research has not provided an understanding of how t...

  17. The impact of changes in the water table and soil moisture on structural stability of buildings and foundation systems : systematic review CEE10-005 (SR90).

    OpenAIRE

    2012-01-01

    This Systematic Review aims to consider the impact of changes in the ground water table and soil moisture regime on structural stability of buildings and foundation systems. The possible changes in the water table levels and soil moisture conditions are expected as a result of environmental change. Building and infrastructure damage occurs where differential movements exceed the thresholds that the buildings or infrastructure can sustain. At locations where uniform vertical settlement domi...

  18. Strength and stability analysis of load-bearing structures of a high-rise building with account for actual positions of reinforced concrete structural members

    Directory of Open Access Journals (Sweden)

    Belostotskiy Aleksandr Mikhaylovich

    2015-04-01

    Full Text Available The given paper is devoted to strength and stability analysis of load-bearing structures of a high-rise (54-storey building with allowance for actual positions of reinforced concrete structural members (columns and walls. Finite element method (FEM is used for structural analysis. The authors present formulations of problems, governing equations, information about basic three-dimensional finite element models (so-called “design” (ideal model, the first “actual” model (taking into account the deviations of positions of columns from the project and the second “actual” model (taking into account the deviations of positions of walls from the project of the coupled system “high-rise building - foundation” within ANSYS Mechanical software and their verification, numerical approach to structural analysis and corresponding solvers. Finite element models include mainly 4-node structural shell elements (suitable for analyzing foundation slabs, floor slabs and load-bearing walls and three-dimensional 2-node beam elements (suitable for analyzing beams and columns, special spring-damper elements and multipoint constraint elements. Detailed finite element mesh on the bottom foundation slab is agreed with the location of piles. The advanced model of Prof. Yu.K. Zaretsky is used for approximation of soil behavior. Construction sequence and various types of nonlinearities are taken into account. The results of modal analysis, static and dynamic analysis with various load combinations (gravity load, facade load, dead (constant loads, temporary loads, wind load, snow load, crown load etc. are considered, the results of the regulatory assessment of the strength of structures (obtained with the use of corresponding software in accordance with design codes of the Russian Federation are under consideration as well. The corresponding displacements, stresses, natural vibration frequencies can be used for research and development of the correct monitoring

  19. A study on the functional assessment of the prestressed system and main structural elements in life extended containment building

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, C. H.; Kim, S. W.; Choi, J. G. [DAEWOO E and C Institute of Costruction Technology, Suwon (Korea, Republic of)] (and others)

    2001-10-15

    The design life of KNGR (Korean Next Generation Reactor) containment buildings is extended from 40 years to 60 years. However, nuclear reactor buildings are passive structures that are impossible to be exchanged in the case of degradation by the deterioration and so on when extending the design life of structures. Therefore, it is necessary to consider the long-term safety endurance in the design and construction of KNGR. Also, ti is judged that choice of the material and various test methods should be prescribed clearly. In this study, the reduction schemes of deterioration and the safety-ensuring schemes are drawn for the expected performance to be maintained from the beginning of the service to the required period together with ensuring the safety and serviceability of KNGR which will be constructed with the design life of 60 years, taking into account the dimensions, selection of material and construction methods in the design and construction stages. Also, the validity is to be examined for the estimation method of long-term losses of stress introduced to KNGR whose design life is increased to 60 years. The durability enhancement scheme on the design and construction for the design life extension of nuclear containment buildings is to be drawn through these studies. These results are utilized as the basic data for the safety inspection and examination guides of KNGR and finally the additional investigations are proposed for the items which require long-term studies.

  20. Research on Technology and Development Direction of Steel Structure Building%建筑钢结构技术与发展方向研究

    Institute of Scientific and Technical Information of China (English)

    张俏; 董羽

    2014-01-01

    In recent years, with the wide application of steel structure in industrial buildings and public buildings, building steel structure of the new technology, new processes and new materials continue to bring forth the new through the old, this paper built in recent years at home and abroad, build_ing steel structure, the introduction of new technology and devel_opment direction of construction steel.%近些年来,随着建筑钢结构在工业建筑和公共建筑中的广泛应用,建筑钢结构的新技术、新工艺和新材料不断推陈出新,本文结合近些年国内外在建筑钢结构的建造的实例,介绍建筑钢结构新技术与发展方向。

  1. Adhesives in Building--Lamination of Structural Timber Beams, Bonding of Cementitious Materials, Bonding of Gypsum Drywall Construction. Proceedings of a Conference of the Building Research Institute, Division of Engineering and Industrial Research (Spring 1960).

    Science.gov (United States)

    National Academy of Sciences - National Research Council, Washington, DC.

    The role of adhesives in building design is discussed. Three major areas are as follows--(1) lamination of structural timber beams, (2) bonding of cementitious materials, and (3) bonding of gypsum drywall construction. Topical coverage includes--(1) structural lamination today, (2) adhesives in use today, (3) new adhesives needed, (4) production…

  2. A novel 300 kW arc plasma inverter system based on hierarchical controlled building block structure

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    To date, the high power arc plasma technology is widely used. A next generation high power arc plasma system based on building block structure is presented. The whole arc plasma inverter system is composed of 12 paralleled units to increase the system output capability. The hierarchical control system is adopted to improve the reliability and flexibility of the high power arc plasma inverter. To ensure the reliable turn on and off of the IGBT module in each building block unit, a special pulse drive circuit is designed by using pulse transformer. The experimental result indicates that the high power arc plasma inverter system can transfer 300 kW arc plasma energy reliably with high efficiency.

  3. Seismic fragility analysis of a nuclear building based on probabilistic seismic hazard assessment and soil-structure interaction analysis

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, R.; Ni, S.; Chen, R.; Han, X.M. [CANDU Energy Inc, Mississauga, Ontario (Canada); Mullin, D. [New Brunswick Power, Point Lepreau, New Brunswick (Canada)

    2016-09-15

    Seismic fragility analyses are conducted as part of seismic probabilistic safety assessment (SPSA) for nuclear facilities. Probabilistic seismic hazard assessment (PSHA) has been undertaken for a nuclear power plant in eastern Canada. Uniform Hazard Spectra (UHS), obtained from the PSHA, is characterized by high frequency content which differs from the original plant design basis earthquake spectral shape. Seismic fragility calculations for the service building of a CANDU 6 nuclear power plant suggests that the high frequency effects of the UHS can be mitigated through site response analysis with site specific geological conditions and state-of-the-art soil-structure interaction analysis. In this paper, it is shown that by performing a detailed seismic analysis using the latest technology, the conservatism embedded in the original seismic design can be quantified and the seismic capacity of the building in terms of High Confidence of Low Probability of Failure (HCLPF) can be improved. (author)

  4. The reaction of the building structure with window unit to the explosiveimpact on the basis of dynamic equation solution

    Directory of Open Access Journals (Sweden)

    Doronin Fedor Leonidovich

    2014-01-01

    Full Text Available When designing residential buildings, additional measures for increasing the strength at dynamic effects indoors are not foreseen. The walls of the structure fixed in the framework are not designed for shock wave caused by explosion of utility gas. When designing a building, the task of the special dynamic load is often reduced to the calculation of the safe shock pressure, exceeding of which leads to the destruction of the structures. The wall with the window area under dynamic effects is a blast relief panel, which reduces the excess pressure inside the room. The proposed method of calculating a design with a window unit allows determining the dynamic reaction of the wall on explosive pulse. The proposed calculation technique of the constructions at shock loads allows tracing the changes of the inertial forces and displacements at any stage of dynamic response. The reaction to dynamic loads can be also set for non-monolithic structures, consisting of different materials with different conditions of fastening. Elastoplastic reaction of a brick wall with glass units was determined using step-by-step method of linear acceleration. The calculation of stress-strain state of brick walls with window panes determined the strength properties of the structures close to the monolithic version. The proposed technique of numerical solution of dynamic equations is applied only in the analysis of elastic systems, in which the dynamic characteristics remain unchanged throughout the reaction process.

  5. Synchrosqueezed wavelet transform-fractality model for locating, detecting, and quantifying damage in smart highrise building structures

    Science.gov (United States)

    Amezquita-Sanchez, Juan P.; Adeli, Hojjat

    2015-06-01

    A new methodology is presented for (a) detecting, (b) locating, and (c) quantifying the damage severity in a smart highrise building structure. The methodology consists of three steps: In step 1, the synchrosqueezed wavelet transform is used to eliminate the noise in the signals. In step 2, a nonlinear dynamics measure based on the chaos theory, fractality dimension (FD), is employed to detect features to be used for damage detection. In step 3, a new structural damage index, based on the estimated FD values, is proposed as a measure of the condition of the structure. Further, the damage location is obtained using the changes of the estimated FD values. Three different FD algorithms for computing the fractality of time series signals are investigated. They are Katz’s FD, Higuchi’s FD, and box dimension. The usefulness and effectiveness of the proposed methodology are validated using the sensed data obtained experimentally for the 1:20 scaled model of a 38-storey concrete building structure.

  6. Structural Health Monitoring of Tall Buildings with Numerical Integrator and Convex-Concave Hull Classification

    Directory of Open Access Journals (Sweden)

    Suresh Thenozhi

    2012-01-01

    Full Text Available An important objective of health monitoring systems for tall buildings is to diagnose the state of the building and to evaluate its possible damage. In this paper, we use our prototype to evaluate our data-mining approach for the fault monitoring. The offset cancellation and high-pass filtering techniques are combined effectively to solve common problems in numerical integration of acceleration signals in real-time applications. The integration accuracy is improved compared with other numerical integrators. Then we introduce a novel method for support vector machine (SVM classification, called convex-concave hull. We use the Jarvis march method to decide the concave (nonconvex hull for the inseparable points. Finally the vertices of the convex-concave hull are applied for SVM training.

  7. Data Collection Handbook to Support Modeling Impacts of Radioactive Material in Soil and Building Structures

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Charley [Argonne National Lab. (ANL), Argonne, IL (United States); Kamboj, Sunita [Argonne National Lab. (ANL), Argonne, IL (United States); Wang, Cheng [Argonne National Lab. (ANL), Argonne, IL (United States); Cheng, Jing-Jy [Argonne National Lab. (ANL), Argonne, IL (United States)

    2015-09-01

    This handbook is an update of the 1993 version of the Data Collection Handbook and the Radionuclide Transfer Factors Report to support modeling the impact of radioactive material in soil. Many new parameters have been added to the RESRAD Family of Codes, and new measurement methodologies are available. A detailed review of available parameter databases was conducted in preparation of this new handbook. This handbook is a companion document to the user manuals when using the RESRAD (onsite) and RESRAD-OFFSITE code. It can also be used for RESRAD-BUILD code because some of the building-related parameters are included in this handbook. The RESRAD (onsite) has been developed for implementing U.S. Department of Energy Residual Radioactive Material Guidelines. Hydrogeological, meteorological, geochemical, geometrical (size, area, depth), crops and livestock, human intake, source characteristic, and building characteristic parameters are used in the RESRAD (onsite) code. The RESRAD-OFFSITE code is an extension of the RESRAD (onsite) code and can also model the transport of radionuclides to locations outside the footprint of the primary contamination. This handbook discusses parameter definitions, typical ranges, variations, and measurement methodologies. It also provides references for sources of additional information. Although this handbook was developed primarily to support the application of RESRAD Family of Codes, the discussions and values are valid for use of other pathway analysis models and codes.

  8. Gamma-ray energy buildup factor calculations and shielding effects of some Jordanian building structures

    Science.gov (United States)

    Sharaf, J. M.; Saleh, H.

    2015-05-01

    The shielding properties of three different construction styles, and building materials, commonly used in Jordan, were evaluated using parameters such as attenuation coefficients, equivalent atomic number, penetration depth and energy buildup factor. Geometric progression (GP) method was used to calculate gamma-ray energy buildup factors of limestone, concrete, bricks, cement plaster and air for the energy range 0.05-3 MeV, and penetration depths up to 40 mfp. It has been observed that among the examined building materials, limestone offers highest value for equivalent atomic number and linear attenuation coefficient and the lowest values for penetration depth and energy buildup factor. The obtained buildup factors were used as basic data to establish the total equivalent energy buildup factors for three different multilayer construction styles using an iterative method. The three styles were then compared in terms of fractional transmission of photons at different incident photon energies. It is concluded that, in case of any nuclear accident, large multistory buildings with five layers exterior walls, style A, could effectively attenuate radiation more than small dwellings of any construction style.

  9. Decision-tree analysis of factors influencing rainfall-related building structure and content damage

    Science.gov (United States)

    Spekkers, M. H.; Kok, M.; Clemens, F. H. L. R.; ten Veldhuis, J. A. E.

    2014-09-01

    Flood-damage prediction models are essential building blocks in flood risk assessments. So far, little research has been dedicated to damage from small-scale urban floods caused by heavy rainfall, while there is a need for reliable damage models for this flood type among insurers and water authorities. The aim of this paper is to investigate a wide range of damage-influencing factors and their relationships with rainfall-related damage, using decision-tree analysis. For this, district-aggregated claim data from private property insurance companies in the Netherlands were analysed, for the period 1998-2011. The databases include claims of water-related damage (for example, damages related to rainwater intrusion through roofs and pluvial flood water entering buildings at ground floor). Response variables being modelled are average claim size and claim frequency, per district, per day. The set of predictors include rainfall-related variables derived from weather radar images, topographic variables from a digital terrain model, building-related variables and socioeconomic indicators of households. Analyses were made separately for property and content damage claim data. Results of decision-tree analysis show that claim frequency is most strongly associated with maximum hourly rainfall intensity, followed by real estate value, ground floor area, household income, season (property data only), buildings age (property data only), a fraction of homeowners (content data only), a and fraction of low-rise buildings (content data only). It was not possible to develop statistically acceptable trees for average claim size. It is recommended to investigate explanations for the failure to derive models. These require the inclusion of other explanatory factors that were not used in the present study, an investigation of the variability in average claim size at different spatial scales, and the collection of more detailed insurance data that allows one to distinguish between the

  10. Brickworx builds recurrent RNA and DNA structural motifs into medium- and low-resolution electron-density maps

    Energy Technology Data Exchange (ETDEWEB)

    Chojnowski, Grzegorz, E-mail: gchojnowski@genesilico.pl [International Institute of Molecular and Cell Biology, Trojdena 4, 02-109 Warsaw (Poland); Waleń, Tomasz [International Institute of Molecular and Cell Biology, Trojdena 4, 02-109 Warsaw (Poland); University of Warsaw, Banacha 2, 02-097 Warsaw (Poland); Piątkowski, Paweł; Potrzebowski, Wojciech [International Institute of Molecular and Cell Biology, Trojdena 4, 02-109 Warsaw (Poland); Bujnicki, Janusz M. [International Institute of Molecular and Cell Biology, Trojdena 4, 02-109 Warsaw (Poland); Adam Mickiewicz University, Umultowska 89, 61-614 Poznan (Poland)

    2015-03-01

    A computer program that builds crystal structure models of nucleic acid molecules is presented. Brickworx is a computer program that builds crystal structure models of nucleic acid molecules using recurrent motifs including double-stranded helices. In a first step, the program searches for electron-density peaks that may correspond to phosphate groups; it may also take into account phosphate-group positions provided by the user. Subsequently, comparing the three-dimensional patterns of the P atoms with a database of nucleic acid fragments, it finds the matching positions of the double-stranded helical motifs (A-RNA or B-DNA) in the unit cell. If the target structure is RNA, the helical fragments are further extended with recurrent RNA motifs from a fragment library that contains single-stranded segments. Finally, the matched motifs are merged and refined in real space to find the most likely conformations, including a fit of the sequence to the electron-density map. The Brickworx program is available for download and as a web server at http://iimcb.genesilico.pl/brickworx.

  11. Effects of Various Blowout Panel Configurations on the Structural Response of LANL Building 16-340 to Internal Explosions

    Energy Technology Data Exchange (ETDEWEB)

    Wilke, Jason P. [New Mexico Inst. of Mining and Technology, Socorro, NM (United States)

    2005-09-01

    The risk of accidental detonation is present whenever any type of high explosives processing activity is performed. These activities are typically carried out indoors to protect processing equipment from the weather and to hide possibly secret processes from view. Often, highly strengthened reinforced concrete buildings are employed to house these activities. These buildings may incorporate several design features, including the use of lightweight frangible blowout panels, to help mitigate blast effects. These panels are used to construct walls that are durable enough to withstand the weather, but are of minimal weight to provide overpressure relief by quickly moving outwards and creating a vent area during an accidental explosion. In this study the behavior of blowout panels under various blast loading conditions was examined. External loadings from explosions occurring in nearby rooms were of primary interest. Several reinforcement systems were designed to help blowout panels resist failure from external blast loads while still allowing them to function as vents when subjected to internal explosions. The reinforcements were studied using two analytical techniques, yield-line analysis and modal analysis, and the hydrocode AUTODYN. A blowout panel reinforcement design was created that could prevent panels from being blown inward by external explosions. This design was found to increase the internal loading of the building by 20%, as compared with nonreinforced panels. Nonreinforced panels were found to increase the structural loads by 80% when compared to an open wall at the panel location.

  12. Uncertainty analysis of practical structural health monitoring systems currently employed for tall buildings consisting of small number of sensors

    Science.gov (United States)

    Hirai, Kenta; Mita, Akira

    2016-04-01

    Because of social background, such as repeated large earthquakes and cheating in design and construction, structural health monitoring (SHM) systems are getting strong attention. The SHM systems are in a practical phase. An SHM system consisting of small number of sensors has been introduced to 6 tall buildings in Shinjuku area. Including them, there are 2 major issues in the SHM systems consisting of small number of sensors. First, optimal system number of sensors and the location are not well-defined. In the practice, system placement is determined based on rough prediction and experience. Second, there are some uncertainties in estimation results by the SHM systems. Thus, the purpose of this research is to provide useful information for increasing reliability of SHM system and to improve estimation results based on uncertainty analysis of the SHM systems. The important damage index used here is the inter-story drift angle. The uncertainty considered here are number of sensors, earthquake motion characteristics, noise in data, error between numerical model and real building, nonlinearity of parameter. Then I have analyzed influence of each factor to estimation accuracy. The analysis conducted here will help to decide sensor system design considering valance of cost and accuracy. Because of constraint on the number of sensors, estimation results by the SHM system has tendency to provide smaller values. To overcome this problem, a compensation algorithm was discussed and presented. The usefulness of this compensation method was demonstrated for 40 story S and RC building models with nonlinear response.

  13. Report on design and technical standard planning of vibration controlling structure on the buildings, in the Tokai Reprocessing Facility, Power Reactor and Nuclear Fuel Development Corporation

    Energy Technology Data Exchange (ETDEWEB)

    Uryu, Mitsuru; Terada, Shuji; Shinohara, Takaharu; Yamazaki, Toshihiko; Nakayama, Kazuhiko [Power Reactor and Nuclear Fuel Development Corp., Tokai, Ibaraki (Japan). Tokai Works; Kondo, Toshinari; Hosoya, Hisashi

    1997-10-01

    The Tokai reprocessing facility buildings are constituted by a lower foundation, vibration controlling layers, and upper structure. At the vibration controlling layer, a laminated rubber aiming support of the building load and extension of the eigenfrequency and a damper aiming absorption of earthquake energy are provided. Of course, the facility buildings are directly supported at the arenaceous shale (Taga Layer) of the Miocene in the Neogene confirmed to the stablest ground, as well the buildings with high vibration resistant importance in Japan. This report shows that when the vibration controlling structure is adopted for the reprocessing facility buildings where such high vibration resistance is required, reduction of input acceleration for equipments and pipings can be achieved and the earthquake resistant safety can also be maintained with sufficient tolerance and reliability. (G.K.)

  14. Comparison Between Structural Analysis of Residential Building (Flat Scheme Subjected to Gravity With Respect to Seismic Forces (In zone II and zone III For Different Storey Heights

    Directory of Open Access Journals (Sweden)

    Pranita R. Kayarkar

    2014-11-01

    Full Text Available The recent development in methods to analyze the RC frame structure brings us to this study. This paper is approach to introduce the comparison between structural analysis of Residential building (Flat Scheme subjected to gravity with respect to seismic forces ( in zone II and zone III for different storey heights. For structural engineers, seismic load should be considered as important aspect that needs to be included in the building design. However majority of buildings constructed in India are designed for gravity loading only and poorly detailed to accommodate lateral loads. The purpose of this paper is to investigate the comparison between structural analysis of residential building subjected to gravity with respect to seismic forces in zone II and zone III for different storey heights. The analysis for residential building (G+3 is carried out by using software SAP by seismic coefficient method. Columns, beams and footing has been drawn. Microsoft office Excel 2007 programs were used for drafting , and analysis of columns, beams and footing. This analysis gives better understanding the seismic performance of buildings. The results show that the building which is designed only for gravity load is found inadequate to resist seismic load in zone II and zone III.

  15. The small scale structure of the interstellar medium in the Orion association: The flotsam of star formation

    Science.gov (United States)

    Sonneborn, G.; Shore, S. N.; Brown, D. N.

    1988-01-01

    The small scale dynamics and structure of the interstellar medium of the Orion OB1b, c association was studied using IUE high dispersion SWP and LWR/LWP spectra. The area surveyed centers on the Belt and encompasses the Orion Cloak. The dynamics and abundances of the ionized and warm neutral gas surrounding the central parts of the association are determined using 35 B stars. Results are compared with the picture of the Orion interstellar medium gained using COPERNICUS, especially for the structure and dynamics of the Orion Cloak.

  16. Research of CBR, DM and smart algorithms based design methods for high-rise building structure form-selection

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shi-hai; LIU Shu-jun; LIU Xiao-yan; OU Jin-ping

    2006-01-01

    First, the high-rise building structure design process is divided into three relevant steps, that is,scheme generation and creation, performance evaluation, and scheme optimization. Then with the application of relational database, the case database of high-rise structures is constructed, the structure form-selection designing methods such as the smart algorithm based on CBR, DM, FINS, NN and GA is presented, and the original forms system of this method and its general structure are given. CBR and DM are used to generate scheme candidates; FINS and NN to evaluate and optimize the scheme performance; GA to create new structure forms.Finally, the application cases are presented, whose results fit in with the real project. It proves by combining and using the expert intelligence, algorithm intelligence and machine intelligence that this method makes good use of not only the engineering project knowledge and expertise but also much deeper knowledge contained in various engineering cases. In other words, it is because the form selection has a strong background support of vast real cases that its results prove more reliable and more acceptable. So the introduction of this method prorides an effective approach to improving the quality, efficiency, automatic and smart level of high-rise structures form selection design.

  17. Parametric modelling and optimization of building structures with Rhinoceros-Grasshopper

    OpenAIRE

    Soklič, Rok

    2015-01-01

    This graduation thesis comprises the use of modern geometry design software in the process of structural design. By implementing parametrically designed geometry and interactively linking 3D computer graphics application software with structural analysis software, tasks involved in structural design (e.g. automatic design data transfer) can be significantly improved. In the first part of the thesis, the basics of NURBS (Non-uniform Rational Basis Spline) mathematical elements are briefly pres...

  18. Modeling of the structural response to fire of a high-rise steel building

    DEFF Research Database (Denmark)

    Gentili, Filippo; Giuliani, Luisa; Bontempi, Franco

    2011-01-01

    of investigations require the consideration of a full nonlinear response of the structure, due to material degradation under fire, possibility of buckling, large displacements and deformations suffered by elements and exploitation of plastic reserve of the structure. The assessment of structural performances...... and for highlighting a possible propagation of the failures to zones of the structure not directly involved in the fire. In order to show the influence of ratio of stiffness between beams and columns, the behavior of two different floors has been studied....

  19. Building a better fragment library for de novo protein structure prediction.

    Directory of Open Access Journals (Sweden)

    Saulo H P de Oliveira

    Full Text Available Fragment-based approaches are the current standard for de novo protein structure prediction. These approaches rely on accurate and reliable fragment libraries to generate good structural models. In this work, we describe a novel method for structure fragment library generation and its application in fragment-based de novo protein structure prediction. The importance of correct testing procedures in assessing the quality of fragment libraries is demonstrated. In particular, the exclusion of homologs to the target from the libraries to correctly simulate a de novo protein structure prediction scenario, something which surprisingly is not always done. We demonstrate that fragments presenting different predominant predicted secondary structures should be treated differently during the fragment library generation step and that exhaustive and random search strategies should both be used. This information was used to develop a novel method, Flib. On a validation set of 41 structurally diverse proteins, Flib libraries presents both a higher precision and coverage than two of the state-of-the-art methods, NNMake and HHFrag. Flib also achieves better precision and coverage on the set of 275 protein domains used in the two previous experiments of the the Critical Assessment of Structure Prediction (CASP9 and CASP10. We compared Flib libraries against NNMake libraries in a structure prediction context. Of the 13 cases in which a correct answer was generated, Flib models were more accurate than NNMake models for 10. "Flib is available for download at: http://www.stats.ox.ac.uk/research/proteins/resources".

  20. Identification of contemporary school dormitory building structure in north China%北方某学校宿舍楼现有结构鉴定

    Institute of Scientific and Technical Information of China (English)

    陆艳鹏

    2012-01-01

    In light of the identification issue of the school dormitory building, taking the school dormitory building in north China as the research target, through testing the bearing capacity of the dormitory building structure, the paper carries out the structural security and seismic identifica- tion. According to the identification conclusions, it puts forward corresponding suggestions, so as to eliminating the safety hazards of the dormitory building structure.%针对学校校舍的鉴定问题,以北方某学校宿舍楼为研究对象,通过对宿舍楼结构的承载力验算,进行了结构安全性及抗震鉴定,根据鉴定结论提出了相应建议,以排除宿舍楼结构安全隐患。

  1. 高层建筑钢结构安装施工技术%Construction technology of steel structure installation of high-rise buildings

    Institute of Scientific and Technical Information of China (English)

    藏勤峰

    2014-01-01

    This paper introduced the common higher intersection operation technology construction requirements, the steel structure easily affect-ed by natural conditions in high-rise building, deeply introduced the steel structure installation and construction technology of high-rise build-ings, in order to realize the steel structure construction optimization of high-rise buildings.%对高层建筑中钢结构易受自然条件影响、常出现立体交叉作业及施工要求较高的特点进行了介绍,并对高层建筑钢结构安装施工技术进行了深入研究,旨在进一步实现高层建筑钢结构施工的优化。

  2. Building Structure Design as an Integral Part of Architecture: A Teaching Model for Students of Architecture

    Science.gov (United States)

    Unay, Ali Ihsan; Ozmen, Cengiz

    2006-01-01

    This paper explores the place of structural design within undergraduate architectural education. The role and format of lecture-based structure courses within an education system, organized around the architectural design studio is discussed with its most prominent problems and proposed solutions. The fundamental concept of the current teaching…

  3. Structural insight into RNA recognition motifs: versatile molecular Lego building blocks for biological systems.

    Science.gov (United States)

    Muto, Yutaka; Yokoyama, Shigeyuki

    2012-01-01

    'RNA recognition motifs (RRMs)' are common domain-folds composed of 80-90 amino-acid residues in eukaryotes, and have been identified in many cellular proteins. At first they were known as RNA binding domains. Through discoveries over the past 20 years, however, the RRMs have been shown to exhibit versatile molecular recognition activities and to behave as molecular Lego building blocks to construct biological systems. Novel RNA/protein recognition modes by RRMs are being identified, and more information about the molecular recognition by RRMs is becoming available. These RNA/protein recognition modes are strongly correlated with their biological significance. In this review, we would like to survey the recent progress on these versatile molecular recognition modules.

  4. Microwave detection of surface and volume moisture in building walls and related structures

    Science.gov (United States)

    Bastida, E. M.; Ricca, A. M.

    Microwave technique for non-contacting volume and surface moisture measurements in concrete and building walls is described. The reflection and attenuation coefficients of an electromagnetic wave, in the microwave spectrum region, impinging upon a humid wall are studied. Reflection and attenuation are related to the water content. The attenuation coefficient is related to the space-average humidity, while reflection measurements depend also on the humidity profile. By means of a computer simulation surface humidity and surface humidity gradient are both measured by reflectometric techniques. Combining reflection and attenuation measurements, information about the humidity profile is obtained in a non-contacting way. Experimental results on reflection and attenuation measurements are also presented.

  5. Development of standards for chemical and biological decontamination of buildings and structures affected by terrorism

    Energy Technology Data Exchange (ETDEWEB)

    Lumley, T.C.; Volchek, K.; Fingas, M. [Environment Canada, Ottawa, ON (Canada). Emergencies Science and Technology Division, Environmental Technology Centre, Science and Technology Branch; Hay, A.W.M. [Leeds Univ., Leeds (United Kingdom)

    2006-07-01

    Currently, there are no suitable standards for determining levels of safety when reoccupying a building that has been recommissioned following a biological or chemical attack. For that reason, this study focused on developing clean-up standards for decontaminating buildings and construction materials after acts of terrorism. Several parameters must be assessed when determining the course of action to decontaminate toxic agents and to rehabilitate facilities. First, the hazardous substance must be positively identified along with the degree of contamination and information on likely receptors. Potential exposure route is also a key consideration in the risk assessment process. A key objective of the study was to develop specific guidelines for ascertaining and defining clean. In particular, standards for chemical and biological agents that pose a real or potential risk for use as agents of terrorism will be developed. The selected agents for standards development were ammonia, fentanyl, malathion, mustard gas, potassium cyanide, ricin, sarin, hepatitis A virus, and bacillus anthracis. The standards will be developed by establishing the relationship between the amount of exposure and expected health effects; assessing real and potential risks by identifying individuals at risk and consideration of all exposure routes; and, characterizing the risk to determine the potential for toxicity or infectivity. For non-carcinogens, this was done through the analysis of other known guidelines. Cancer-slope factors will be considered for carcinogens. The standards will be assessed in the laboratory using animal models. The guidelines and standards are intended for first-responders and are scheduled for development by the end of 2006. 15 refs., 3 tabs.

  6. BriX: a database of protein building blocks for structural analysis, modeling and design.

    Science.gov (United States)

    Vanhee, Peter; Verschueren, Erik; Baeten, Lies; Stricher, Francois; Serrano, Luis; Rousseau, Frederic; Schymkowitz, Joost

    2011-01-01

    High-resolution structures of proteins remain the most valuable source for understanding their function in the cell and provide leads for drug design. Since the availability of sufficient protein structures to tackle complex problems such as modeling backbone moves or docking remains a problem, alternative approaches using small, recurrent protein fragments have been employed. Here we present two databases that provide a vast resource for implementing such fragment-based strategies. The BriX database contains fragments from over 7000 non-homologous proteins from the Astral collection, segmented in lengths from 4 to 14 residues and clustered according to structural similarity, summing up to a content of 2 million fragments per length. To overcome the lack of loops classified in BriX, we constructed the Loop BriX database of non-regular structure elements, clustered according to end-to-end distance between the regular residues flanking the loop. Both databases are available online (http://brix.crg.es) and can be accessed through a user-friendly web-interface. For high-throughput queries a web-based API is provided, as well as full database downloads. In addition, two exciting applications are provided as online services: (i) user-submitted structures can be covered on the fly with BriX classes, representing putative structural variation throughout the protein and (ii) gaps or low-confidence regions in these structures can be bridged with matching fragments.

  7. Application of a structure with a diode thermal effect for solar heating and cooling of a building; Application d'une structure a effet de diode thermique au chauffage et a la climatisation solaire d'un local

    Energy Technology Data Exchange (ETDEWEB)

    Boukadida, N. [Faculte des Sciences de Monastir (Tunisia); Vullierme, J.J. [Ecole Nationale Superieure de Mecanique et d' Aerotechnique (ENSMA), Lab. d' Etudes Thermiques, 86 - Poitiers (France)

    2002-07-01

    The aim of this study is to present the effect of a structure with a diode thermal effect on the building thermal behavior. Numerical simulations allowed us to compare the thermal behavior of a building equipped with this structure on its east, south and west frontages to that of standing or conventional building with large or low inertia. Results showed that the structure has a diode thermal effect mainly for the heating application. The revetment nature of the interior structure sides has an effect on the total coefficient of heat transfer The efficiency of this structure is sensible for cases where we can allow a low temperature inside the building during the winter season for a heating application and a high temperature during the summer season for a cooling application. (authors)

  8. A Two-step Approach to Progressive Collapse Analysis of Building Structures under Blast Loading

    Institute of Scientific and Technical Information of China (English)

    XU Jun-xian; LIU Xi-la

    2009-01-01

    Structural collapse under blast loads is a very complex process. For several decades, the engineering profession has considered some approaches to analyze the essential physics of collapse phenomena. Recently, the interest in this topic has risen to an apex since the collapse of the World Trade Center towers. A two-step analysis approach to capture the characteristics of structural collapse during explosions is proposed. A numerical example is presented to illustrate the performance of the presented approach.

  9. Chapter 1: building the ground for the first two protein structures: myoglobin and haemoglobin.

    Science.gov (United States)

    Strandberg, Bror

    2009-09-11

    Fifty years ago, Max Perutz and John Kendrew at Cambridge University achieved something that many people at the time considered impossible: they were the first to use x-ray crystallography to decipher the molecular structures of proteins: haemoglobin and myoglobin. They found that both molecules were built from Linus Pauling's alpha helices, but folded and packed together in a complicated manner that never could have been deciphered by any other technique.With structure information in hand they could then explain how haemoglobin in the bloodstream binds and releases oxygen on cue, how it passes its cargo on to the related storage protein myoglobin, and how a single amino acid mutation can produce the catastrophe known as sickle-cell anemia. Perutz and Kendrew also observed that the folding of helices was identical in myoglobin and the two chains of haemoglobin, and this along with the simultaneously evolving new technique of amino acid sequence analysis established for the first time the concept of molecular evolution. The crystallographic puzzle was "cracked" by Perutz when he demonstrated that the binding of only two heavy metal atoms to horse haemoglobin changed the x-ray pattern enough to allow him to solve the "phase problem" and circumvent the main obstacle to protein crystal structure analysis. Because myoglobin has a single chain whereas haemoglobin has four, Kendrew's work with myoglobin progressed more rapidly; a low resolution structure appeared in 1956 and the high resolution structure in 1959. That same year saw the low resolution picture of haemoglobin, and the high resolution structure followed shortly thereafter. Much of the work in structure analysis was carried out by visiting postdoctoral fellows and technicians, under the watchful eye of Perutz and Kendrew. This celebratory review has been written by three of those former postdoctorals: Strandberg and Dickerson from the myoglobin project, and Rossmann from the haemoglobin.

  10. Importance of Building Code

    Directory of Open Access Journals (Sweden)

    Reshmi Banerjee

    2015-06-01

    Full Text Available A building code, or building control, is a set of rules that specify the minimum standards for constructed objects such as buildings and non building structures. The main purpose of building codes are to protect public health, safety and general welfare as they relate to the construction and occupancy of buildings and structures. The building code becomes law of a particular jurisdiction when formally enacted by the appropriate governmental or private authority. Building codes are generally intended to be applied by architects, engineers, constructors and regulators but are also used for various purposes by safety inspectors, environmental scientists, real estate developers, subcontractors, manufacturers of building products and materials, insurance companies, facility managers, tenants and others.

  11. Merchants, ports and hinterlands : the building of sea-port structures in the Early Modern Porto

    Directory of Open Access Journals (Sweden)

    Amândio Jorge Morais Barros

    2008-01-01

    Full Text Available Emerging in the Middle Ages, Porto became one of the most important ports of the Iberian Peninsula. The city’s affirmation over the nearby territory was accompanied by the expansion of business towards the northern markets of Flanders, Brabant, Great Britain and northern France (Brittany and Normandy, stimulating the emergence of a merchant navy, and inspiring a set of engineering works meant to organize the harbour. With this paper, I’ll pay attention to the role performed by small ports and apparently modest business centres in the building and organization of the first global age. The history of such port like Porto will contribute to enlighten fields of interaction that existed between the port-cities and their umlands and hinterlands, which supported its economy, mould a significant part of its society, and influenced its cultural standards. In this study I’ll present the most important facts of the process of territorial domination, and the way things were conducted in order to get effective its mercantile economy. Charts will be presented and comment, once they are very informative to this evolution, and I’ll also emphasize the international context in which it occurred.

  12. Suppression of mechanical vibrations in a building-like structure using a passive/active autoparametric absorber

    Science.gov (United States)

    Abundis-Fong, H. F.; Silva-Navarro, G.

    2014-03-01

    An experimental investigation is carried out on a system consisting of a primary structure coupled with a passive/active autoparametric vibration absorber. The primary structure consists of a building-like mechanical structure, it has three rigid floors connected by flexible columns made from aluminium strips, while the absorber consists of a cantilever beam with a PZT patch actuator actively controlled through an acquisition card. The whole system, which is a coupled non-linear oscillator, is subjected to sinusoidal excitation obtained from an electromechanical shaker in the neighborhood of internal resonances. The natural frequency of the absorber is tuned to be one-half of any of the natural frequencies of the main system. With the addition of a PZT actuator, the autoparametric vibration absorber is made active, thus enabling the possibility to control the effective stiffness associated to the passive absorber and, as a consequence, the implementation of an active vibration control scheme able to preserve, as possible, the autoparametric interaction as well as to compensate varying excitation frequencies. This active vibration absorber employs feedback information from an accelerometer on the primary structure, an accelerometer on the tip of the beam absorber and a strain gage on the base of the beam, feedforward information from the excitation force and on-line computations from the nonlinear approximate frequency response, parameterized in terms of a proportional gain provided by a voltage input to the PZT actuator, thus providing a mechanism to asymptotically track an optimal, robust and stable attenuation solution on the primary system.

  13. Recorded motions of the 6 April 2009 Mw 6.3 L'Aquila, Italy, earthquake and implications for building structural damage: Overview

    Science.gov (United States)

    Celebi, M.; Bazzurro, P.; Chiaraluce, L.; Clemente, P.; Decanini, L.; Desortis, A.; Ellsworth, W.; Gorini, A.; Kalkan, E.; Marcucci, S.; Milana, G.; Mollaioli, F.; Olivieri, M.; Paolucci, R.; Rinaldis, D.; Rovelli, A.; Sabetta, F.; Stephens, C.

    2010-01-01

    The normal-faulting earthquake of 6 April 2009 in the Abruzzo Region of central Italy caused heavy losses of life and substantial damage to centuriesold buildings of significant cultural importance and to modern reinforcedconcrete- framed buildings with hollow masonry infill walls. Although structural deficiencies were significant and widespread, the study of the characteristics of strong motion data from the heavily affected area indicated that the short duration of strong shaking may have spared many more damaged buildings from collapsing. It is recognized that, with this caveat of shortduration shaking, the infill walls may have played a very important role in preventing further deterioration or collapse of many buildings. It is concluded that better new or retrofit construction practices that include reinforcedconcrete shear walls may prove helpful in reducing risks in such seismic areas of Italy, other Mediterranean countries, and even in United States, where there are large inventories of deficient structures. ?? 2010, Earthquake Engineering Research Institute.

  14. The detection and identification to a brick structure residential building%某砖混结构住宅楼检测鉴定

    Institute of Scientific and Technical Information of China (English)

    郭贺君

    2015-01-01

    Taking a brick structure residential building as an example,this paper made detection and identification to the residential building foundation,upper structure component,material strength and structure bearing capacity etc. ,and put forward corresponding reinforcement sug-gestion for its detection results,in order to assure the safety,applicability and durability of building structure.%以某砖混结构住宅楼为例,对该住宅楼地基基础、上部结构构件、材料强度及结构承载力等进行了检测鉴定,并针对其检测结果提出了相应的加固建议,以保证建筑结构的安全性、适用性及耐久性。

  15. A seismic design of nuclear reactor building structures applying seismic isolation system in a seismicity region-a feasibility case study in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Kubo, Tetsuo [The University of Tokyo, Tokyo (Japan); Yamamoto, Tomofumi; Sato, Kunihiko [Mitsubishi Heavy Industries, Ltd., Kobe (Japan); Jimbo, Masakazu [Toshiba Corporation, Yokohama (Japan); Imaoka, Tetsuo [Hitachi-GE Nuclear Energy, Ltd., Hitachi (Japan); Umeki, Yoshito [Chubu Electric Power Co. Inc., Nagoya (Japan)

    2014-10-15

    A feasibility study on the seismic design of nuclear reactor buildings with application of a seismic isolation system is introduced. After the Hyogo-ken Nanbu earthquake in Japan of 1995, seismic isolation technologies have been widely employed for commercial buildings. Having become a mature technology, seismic isolation systems can be applied to NPP facilities in areas of high seismicity. Two reactor buildings are discussed, representing the PWR and BWR buildings in Japan, and the application of seismic isolation systems is discussed. The isolation system employing rubber bearings with a lead plug positioned (LRB) is examined. Through a series of seismic response analyses using the so-named standard design earthquake motions covering the design basis earthquake motions obtained for NPP sites in Japan, the responses of the seismic isolated reactor buildings are evaluated. It is revealed that for the building structures examined herein: (1) the responses of both isolated buildings and isolating LRBs fulfill the specified design criteria; (2) the responses obtained for the isolating LRBs first reach the ultimate condition when intensity of motion is 2.0 to 2.5 times as large as that of the design-basis; and (3) the responses of isolated reactor building fall below the range of the prescribed criteria.

  16. How to build a pathogen detector: structural basis of NB-LRR function

    NARCIS (Netherlands)

    Takken, F.L.W.; Goverse, A.

    2012-01-01

    Many plant disease resistance (R) proteins belong to the family of nucleotide-binding-leucine rich repeat (NB-LRR) proteins. NB-LRRs mediate recognition of pathogen-derived effector molecules and subsequently activate host defence. Their multi-domain structure allows these pathogen detectors to simu

  17. Community structure of filamentous, sheath-building sulfur bacteria, Thioploca spp, off the coast of Chile

    DEFF Research Database (Denmark)

    Schulz, HN; Jørgensen, BB; Fossing, HA

    1996-01-01

    The filamentous sulfur bacteria Thioploca spp, produce dense bacterial mats in the shelf area off the coast of Chile and Peru. The mat consists of common sheaths, shared by many filaments, that reach 5 to 10 cm dean into the sediment, The structure of the Thioploca communities off the Bay...

  18. Molecular structure of basic oligomeric building units of heparan-sulfate glycosaminoglycans

    NARCIS (Netherlands)

    Remko, Milan; Van Duijnen, Piet Th.; Broer, Ria

    2010-01-01

    This study reports in detail the results of systematic large-scale theoretical investigations of the acidic dimeric structural units (D-E, E-F, F-G, and G-H) and pentamer D-E-F-G-H (fondaparinux) of the glycosaminoglycan heparin, and their anionic forms. The geometries and energies of these oligomer

  19. Porous Network Concrete: a bio-inspired building component to make concrete structures self-healing

    NARCIS (Netherlands)

    Sangadji, S.

    2015-01-01

    The high energy consumption, its corresponding emission of CO2 and financial losses due to premature failure are the pressing sustainability issues which must be tackled by the concrete infrastructure industry. Enhancement of concrete materials and durability of structures (designing new infrastruct

  20. The need for the solid modelling of structure in the archaeology of buildings

    Directory of Open Access Journals (Sweden)

    Robert Daniels

    1997-03-01

    Full Text Available Three-dimensional modelling is an attempt to represent the world in three dimensions, simplifying through deliberate assumptions. In archaeology, this has developed as an extension of the traditional use of three-dimensional drawings to help present and record data. The debate in the archaeological literature over whether surface or solid modellers should be used is one based on the premise that the purpose of three-dimensional modelling is data visualisation. This concentration on perception modelling has been at the expense of research on the modelling of structure. Surface and Solid Modellers are introduced and defined. I argue that developments in modelling software mean that there is no longer a clear distinction between the two types of software along application lines. We should think of models in terms of their applications rather than the software which generates them. Although data visualisation (including virtual reality is an important part of three-dimensional modelling, I argue that it should be explicitly divorced from the related field of photo-realism at a research level. Perception modelling can be performed by surface or solid modellers. Modelling structure is better performed with a solid modeller, if we wish to be as explicit as possible in our modelling. A structural model can be used as a spatial database. If we wish to ask questions about the physical properties of a structure, then we must use solid modellers. In addition to the engineering properties of structures, solid modellers can also be used to answer questions about the economics of construction. For historical reasons, the construction industry has preferred to use surface modellers, but I argue for the advantages of solid modelling in the archaeological study of construction.

  1. Theoretical and numerical analysis of layered cylindrical p entamo de acoustic cloak%圆柱形分层五模材料声学隐身衣的理论与数值分析

    Institute of Scientific and Technical Information of China (English)

    张向东; 陈虹; 王磊; 赵志高; 赵爱国

    2015-01-01

    As a newly-developed method, acoustic cloak made of pentamode materials is on its speedway to the promising potential application. However, physical fabrication of pentamode cloak with continuously varying material parameters can be a tough work, if not totally impossible. Layering is a natural compromise to bypass this quandary. Researches on layering effects of inertial cloak are ample. However, researches on layering pentamode acoustic cloak are relatively limited. Among these researches Scandrett extends the effective bandwidth through optimization of material parame-ters[2010 J. Acoust. Soc. Am. 127 2856, 2011 Wave Motion. 48 505]. The present work concerns the layering effects of pentamode acoustic cloak. By comparing with precedent results, the present paper has two major innovations: Firstly, cylinder is chosen to be the basic geometry. This is of obvious advantage since cylinder is the basic geometry of acoustic cloak’s important potential host. Secondly, effects of layers’ number and thickness distribution on the stealth effect are analyzed. The two are key parameters to be determined in the layering process. This paper is organized as follows: Firstly, analytical expression of the scattering pressure field of layered cloak is deduced by means of variables separation. In this process Fourier expansion plays a key role. And the harmonic assumption of the incident acoustic wave is made. Secondly, typical cases are calculated to verify the validation of the theoretical analysis. First let material parameters tend towards that of water, and compare the scattering field with that of the bare rigid object when the cloak is replaced by water. Second let the layering number goes to infinity, and compare the scattering field with that of the continuous cloak. Phenomena conforming with basic physical laws are observed. And validity of the theory and codes is confirmed. Thirdly, effects of layers’ number and thickness distribution on the stealth character are

  2. Combining a Ru(II) "Building Block" and Rapid Screening Approach to Identify DNA Structure-Selective "Light Switch" Compounds.

    Science.gov (United States)

    Wachter, Erin; Moyá, Diego; Glazer, Edith C

    2017-02-13

    A chemically reactive Ru(II) "building block", able to undergo condensation reactions with substituted diamines, was utilized to create a small library of luminescent "light switch" dipyrido-[3,2-a:2',3'-c] phenazine (dppz) complexes. The impact of substituent identity, position, and the number of substituents on the light switch effect was investigated. An unbiased, parallel screening approach was used to evaluate the selectivity of the compounds for a variety of different biomolecules, including protein, nucleosides, single stranded DNA, duplex DNA, triplex DNA, and G-quadruplex DNA. Combining these two approaches allowed for the identification of hit molecules that showed different selectivities for biologically relevant DNA structures, particularly triplex and quadruplex DNA.

  3. Building Structured Personal Health Records from Photographs of Printed Medical Records.

    Science.gov (United States)

    Li, Xiang; Hu, Gang; Teng, Xiaofei; Xie, Guotong

    2015-01-01

    Personal health records (PHRs) provide patient-centric healthcare by making health records accessible to patients. In China, it is very difficult for individuals to access electronic health records. Instead, individuals can easily obtain the printed copies of their own medical records, such as prescriptions and lab test reports, from hospitals. In this paper, we propose a practical approach to extract structured data from printed medical records photographed by mobile phones. An optical character recognition (OCR) pipeline is performed to recognize text in a document photo, which addresses the problems of low image quality and content complexity by image pre-processing and multiple OCR engine synthesis. A series of annotation algorithms that support flexible layouts are then used to identify the document type, entities of interest, and entity correlations, from which a structured PHR document is built. The proposed approach was applied to real world medical records to demonstrate the effectiveness and applicability.

  4. Building the Chessboard-like Supramolecular Structure on Au (111) Surfaces

    CERN Document Server

    Dou, Ruifen; Zhang, Ping; Zhong, Dingyong; Fuchs, Harald; Wang, Yue; Chi, Lifeng

    2013-01-01

    We investigate an anthracene derivative, 3(5)-(9-anthryl) pyrazole (ANP), self-assembled on the Au (111) surface by means of scanning tunneling microscopy (STM) and density functional theory (DFT) calculations. A chessboard-like network structure composed of ANP molecules is found, covering the whole Au (111) substrate. Our STM results and DFT calculations reveal that the formation of chessboard-like networks originates from a basic unit cell, a tetramer structure, which is formed by four ANP molecules connected through C-H-N hydrogen-bonds. The hydrogen bonds inside each tetramer and the molecular adsorption interaction are fundamentally important in providing a driving force for formation of the supramolecular networks.

  5. Building Technology Forecast and Evaluation (BTFE). Volume 2. Evaluation of Two Structural Systems

    Science.gov (United States)

    1990-11-01

    are all one piece of formwork , erected and stripped as a single unit. Use of half or full tunnels depends on the room width, form weight, and crane...expected to be good. 1.3 Formwork / Tunnel lorms are metal sheets and are E Temporary designed adequately; scaffolding is Supports used as required. 1.4...structural systems with potential advantage to the U.S. Army Corps of Engineers (USACE): tunnel forming systems and composite panellzed systems. Volume 11

  6. Building Structured Personal Health Records from Photographs of Printed Medical Records

    OpenAIRE

    Li, Xiang; Hu, Gang; Teng, Xiaofei; Xie, Guotong

    2015-01-01

    Personal health records (PHRs) provide patient-centric healthcare by making health records accessible to patients. In China, it is very difficult for individuals to access electronic health records. Instead, individuals can easily obtain the printed copies of their own medical records, such as prescriptions and lab test reports, from hospitals. In this paper, we propose a practical approach to extract structured data from printed medical records photographed by mobile phones. An optical chara...

  7. X-Ray Structures of the Hexameric Building Block of the HIV Capsid

    Energy Technology Data Exchange (ETDEWEB)

    Pornillos, Owen; Ganser-Pornillos, Barbie K.; Kelly, Brian N.; Hua, Yuanzi; Whitby, Frank G.; Stout, C. David; Sundquist, Wesley I.; Hill, Christopher P.; Yeager, Mark; (Scripps); (Utah)

    2009-09-11

    The mature capsids of HIV and other retroviruses organize and package the viral genome and its associated enzymes for delivery into host cells. The HIV capsid is a fullerene cone: a variably curved, closed shell composed of approximately 250 hexamers and exactly 12 pentamers of the viral CA protein. We devised methods for isolating soluble, assembly-competent CA hexamers and derived four crystallographically independent models that define the structure of this capsid assembly unit at atomic resolution. A ring of six CA N-terminal domains form an apparently rigid core, surrounded by an outer ring of C-terminal domains. Mobility of the outer ring appears to be an underlying mechanism for generating the variably curved lattice in authentic capsids. Hexamer-stabilizing interfaces are highly hydrated, and this property may be key to the formation of quasi-equivalent interactions within hexamers and pentamers. The structures also clarify the molecular basis for capsid assembly inhibition and should facilitate structure-based drug design strategies.

  8. Structural geology and geophysics as a support to build a hydrogeologic model of granite rock

    Science.gov (United States)

    Martinez-Landa, Lurdes; Carrera, Jesús; Pérez-Estaún, Andrés; Gómez, Paloma; Bajos, Carmen

    2016-06-01

    A method developed for low-permeability fractured media was applied to understand the hydrogeology of a mine excavated in a granitic pluton. This method includes (1) identifying the main groundwater-conducting features of the medium, such as the mine, dykes, and large fractures, (2) implementing this factors as discrete elements into a three-dimensional numerical model, and (3) calibrating these factors against hydraulic data . A key question is how to identify preferential flow paths in the first step. Here, we propose a combination of several techniques. Structural geology, together with borehole sampling, geophysics, hydrogeochemistry, and local hydraulic tests aided in locating all structures. Integration of these data yielded a conceptual model of the site. A preliminary calibration of the model was performed against short-term (pumping tests, which facilitated the characterization of some of the fractures. The hydraulic properties were then used for other fractures that, according to geophysics and structural geology, belonged to the same families. Model validity was tested by blind prediction of a long-term (4 months) large-scale (1 km) pumping test from the mine, which yielded excellent agreement with the observations. Model results confirmed the sparsely fractured nature of the pluton, which has not been subjected to glacial loading-unloading cycles and whose waters are of Na-HCO3 type.

  9. An Electronic Structure Approach to Charge Transfer and Transport in Molecular Building Blocks for Organic Optoelectronics

    Science.gov (United States)

    Hendrickson, Heidi Phillips

    A fundamental understanding of charge separation in organic materials is necessary for the rational design of optoelectronic devices suited for renewable energy applications and requires a combination of theoretical, computational, and experimental methods. Density functional theory (DFT) and time-dependent (TD)DFT are cost effective ab-initio approaches for calculating fundamental properties of large molecular systems, however conventional DFT methods have been known to fail in accurately characterizing frontier orbital gaps and charge transfer states in molecular systems. In this dissertation, these shortcomings are addressed by implementing an optimally-tuned range-separated hybrid (OT-RSH) functional approach within DFT and TDDFT. The first part of this thesis presents the way in which RSH-DFT addresses the shortcomings in conventional DFT. Environmentally-corrected RSH-DFT frontier orbital energies are shown to correspond to thin film measurements for a set of organic semiconducting molecules. Likewise, the improved RSH-TDDFT description of charge transfer excitations is benchmarked using a model ethene dimer and silsesquioxane molecules. In the second part of this thesis, RSH-DFT is applied to chromophore-functionalized silsesquioxanes, which are currently investigated as candidates for building blocks in optoelectronic applications. RSH-DFT provides insight into the nature of absorptive and emissive states in silsesquioxanes. While absorption primarily involves transitions localized on one chromophore, charge transfer between chromophores and between chromophore and silsesquioxane cage have been identified. The RSH-DFT approach, including a protocol accounting for complex environmental effects on charge transfer energies, was tested and validated against experimental measurements. The third part of this thesis addresses quantum transport through nano-scale junctions. The ability to quantify a molecular junction via spectroscopic methods is crucial to their

  10. 建筑结构中结构动力学的防震减震应用研究%Research on the Shock-absorbing and Shockproof Application of Structural Dynamics in Building Structure

    Institute of Scientific and Technical Information of China (English)

    王敬东; 胡晓飞; 董一丁

    2013-01-01

    Structure dynamics plays an important role in stru-ctural design, structural dynamics and the building structure is an organic whole, complement and indispensable with each ot-her. In this paper, through the description of the building struc-ture and dynamics, it further analyzes the shock-absorbing and shockproof application of structural dynamics in building stru-cture.%结构动力学在抗震结构设计中具有重要的作用,结构动力学与建筑结构是相辅相成、缺一不可的有机整体。本文通过对建筑结构和动力学的相关阐述,进一步分析了建筑结构中动力学的防震减震应用。

  11. Estimating structural collapse fragility of generic building typologies using expert judgment

    Science.gov (United States)

    Jaiswal, Kishor; Wald, David J.; Perkins, David M.; Aspinall, Willy P.; Kiremidjian, Anne S.

    2014-01-01

    The structured expert elicitation process proposed by Cooke (1991), hereafter referred to as Cooke's approach, is applied for the first time in the realm of structural collapse-fragility assessment for selected generic construction types. Cooke's approach works on the principle of objective calibration scoring of judgments couple with hypothesis testing used in classical statistics. The performance-based scoring system reflects the combined measure of an expert's informativeness about variables in the problem are under consideration, and their ability to enumerate, in a statistically accurate way through expressing their true beliefs, the quantitative uncertainties associated with their assessments. We summarize the findings of an expert elicitation workshop in which a dozen earthquake-engineering professionals from around the world were engaged to estimate seismic collapse fragility for generic construction types. Development of seismic collapse fragility-functions was accomplished by combining their judgments using weights derived from Cooke's method. Although substantial effort was needed to elicit the inputs of these experts successfully, we anticipate that the elicitation strategy described here will gain momentum in a wide variety of earthquake seismology and engineering hazard and risk analyses where physical model and data limitations are inherent and objective professional judgment can fill gaps.

  12. Full structure building and docking of NifS from extremophile Acidithiobacillus ferrooxidans

    Institute of Scientific and Technical Information of China (English)

    LIU Yuan-dong; QIU Guan-zhou; WANG Hai-dong; JIANG Ying; ZHANG Cheng-gui; XIA Le-xia

    2008-01-01

    The gene iscS-2 from extremophile Acidithiobacillus ferrooxidans may play a crucial role in nitrogenase maturation. To investigate the protein encoded by this gene, a reliable integral three-dimensional molecular structure was built. The obtained structure was further used to search binding sites, carry out the flexible docking with cofactor pyridoxal 5′-phosphate(PLP) and substrate cysteine, and identify its key residues. The docking results of PLP reveal that the residues of Lys203, His100, Thr73, Ser200, His202, Asp177 and Gln180 have large interaction energies and/or hydrogen bonds fixation with PLP. The docking results of cysteine show that the amino group in cysteine is very near His100, Lys203 and PLP, and the interaction energies for cysteine with them are very big. These identified residues are in line with the experimental facts of NifS from other sources. Moreover, the four residues of Asn152, Val179, Ala102 and Met148 in the PLP docking and the two residues of Lys208 and Ala102 in the cysteine docking also have large interaction energies, which are fitly conserved in NifS from all kinds of sources but have not been identified before. According to these results, this gene encodes NifS protein, and the substrate cysteine can be effectively recruited into the active site. Furthermore, all of the above detected key residues are directly responsible for the binding and/or catalysis of PLP and cysteine.

  13. Building Block Approach' for Structural Analysis of Thermoplastic Composite Components for Automotive Applications

    Science.gov (United States)

    Carello, M.; Amirth, N.; Airale, A. G.; Monti, M.; Romeo, A.

    2017-02-01

    Advanced thermoplastic prepreg composite materials stand out with regard to their ability to allow complex designs with high specific strength and stiffness. This makes them an excellent choice for lightweight automotive components to reduce mass and increase fuel efficiency, while maintaining the functionality of traditional thermosetting prepreg (and mechanical characteristics) and with a production cycle time and recyclability suited to mass production manufacturing. Currently, the aerospace and automotive sectors struggle to carry out accurate Finite Elements (FE) component analyses and in some cases are unable to validate the obtained results. In this study, structural Finite Elements Analysis (FEA) has been done on a thermoplastic fiber reinforced component designed and manufactured through an integrated injection molding process, which consists in thermoforming the prepreg laminate and overmolding the other parts. This process is usually referred to as hybrid molding, and has the provision to reinforce the zones subjected to additional stresses with thermoformed themoplastic prepreg as required and overmolded with a shortfiber thermoplastic resin in single process. This paper aims to establish an accurate predictive model on a rational basis and an innovative methodology for the structural analysis of thermoplastic composite components by comparison with the experimental tests results.

  14. Phylogeographic analysis reveals significant spatial genetic structure of Incarvillea sinensis as a product of mountain building

    Directory of Open Access Journals (Sweden)

    Chen Shaotian

    2012-04-01

    Full Text Available Abstract Background Incarvillea sinensis is widely distributed from Southwest China to Northeast China and in the Russian Far East. The distribution of this species was thought to be influenced by the uplift of the Qinghai-Tibet Plateau and Quaternary glaciation. To reveal the imprints of geological events on the spatial genetic structure of Incarvillea sinensis, we examined two cpDNA segments ( trnH- psbA and trnS- trnfM in 705 individuals from 47 localities. Results A total of 16 haplotypes was identified, and significant genetic differentiation was revealed (GST =0.843, NST = 0.975, P  Conclusions The results revealed that the uplift of the Qinghai-Tibet Plateau likely resulted in the significant divergence between the lineage in the eastern Qinghai-Tibet Plateau and the other one outside this area. The diverse niches in the eastern Qinghai-Tibet Plateau created a wide spectrum of habitats to accumulate and accommodate new mutations. The features of genetic diversity of populations outside the eastern Qinghai-Tibet Plateau seemed to reveal the imprints of extinction during the Glacial and the interglacial and postglacial recolonization. Our study is a typical case of the significance of the uplift of the Qinghai-Tibet Plateau and the Quaternary Glacial in spatial genetic structure of eastern Asian plants, and sheds new light on the evolution of biodiversity in the Qinghai-Tibet Plateau at the intraspecies level.

  15. Architectural Survey at Joint Base Langley-Eustis of Fort Eustis Buildings and Structures Built 1946-1975: Volume 2 (Inventory Forms)

    Science.gov (United States)

    2015-12-01

    The canopy structure has the overhanging metal fascia system detail similar to that on the main building. This canopy was a later addition to the...exhibit areas covered with metal shed structures NO. OF STORIES 1 FOOTPRINT Rectangular ROOF FORM Shallow gable FOUNDATION Concrete WALLS...veneer wall on the front elevation and metal clad exterior walls on the sides and rear elevations - One-story structure - Shallow gable roof with

  16. Lightweight object oriented structure analysis: tools for building tools to analyze molecular dynamics simulations.

    Science.gov (United States)

    Romo, Tod D; Leioatts, Nicholas; Grossfield, Alan

    2014-12-15

    LOOS (Lightweight Object Oriented Structure-analysis) is a C++ library designed to facilitate making novel tools for analyzing molecular dynamics simulations by abstracting out the repetitive tasks, allowing developers to focus on the scientifically relevant part of the problem. LOOS supports input using the native file formats of most common biomolecular simulation packages, including CHARMM, NAMD, Amber, Tinker, and Gromacs. A dynamic atom selection language based on the C expression syntax is included and is easily accessible to the tool-writer. In addition, LOOS is bundled with over 140 prebuilt tools, including suites of tools for analyzing simulation convergence, three-dimensional histograms, and elastic network models. Through modern C++ design, LOOS is both simple to develop with (requiring knowledge of only four core classes and a few utility functions) and is easily extensible. A python interface to the core classes is also provided, further facilitating tool development.

  17. The GlycanBuilder: a fast, intuitive and flexible software tool for building and displaying glycan structures

    Directory of Open Access Journals (Sweden)

    Dell Anne

    2007-08-01

    Full Text Available Abstract Background Carbohydrates play a critical role in human diseases and their potential utility as biomarkers for pathological conditions is a major driver for characterization of the glycome. However, the additional complexity of glycans compared to proteins and nucleic acids has slowed the advancement of glycomics in comparison to genomics and proteomics. The branched nature of carbohydrates, the great diversity of their constituents and the numerous alternative symbolic notations, make the input and display of glycans not as straightforward as for example the amino-acid sequence of a protein. Every glycoinformatic tool providing a user interface would benefit from a fast, intuitive, appealing mechanism for input and output of glycan structures in a computer readable format. Results A software tool for building and displaying glycan structures using a chosen symbolic notation is described here. The "GlycanBuilder" uses an automatic rendering algorithm to draw the saccharide symbols and to place them on the drawing board. The information about the symbolic notation is derived from a configurable graphical model as a set of rules governing the aspect and placement of residues and linkages. The algorithm is able to represent a structure using only few traversals of the tree and is inherently fast. The tool uses an XML format for import and export of encoded structures. Conclusion The rendering algorithm described here is able to produce high-quality representations of glycan structures in a chosen symbolic notation. The automated rendering process enables the "GlycanBuilder" to be used both as a user-independent component for displaying glycans and as an easy-to-use drawing tool. The "GlycanBuilder" can be integrated in web pages as a Java applet for the visual editing of glycans. The same component is available as a web service to render an encoded structure into a graphical format. Finally, the "GlycanBuilder" can be integrated into other

  18. Steel structure (bridge and building); Doboku/kenchiku bun`ya ni okeru yosetsu gijutsu no tenkai

    Energy Technology Data Exchange (ETDEWEB)

    Fukazawa, M. [Yokogawa Bridge Corp., Tokyo (Japan)

    1996-01-05

    In this article, the trends of welding engineering are discussed in two groups, namely bridges and steel frames. First of all, in the field of bridges, as the themes of technical innovation of steel bridges, the challenge to build long span bridges, coping with new structural forms, and rationalization of general bridges are selected. Concerning very long bridges, considerable elongation of its spans and technological development for materials, design, construction and erection relating to improvement of profitability become inevitable. Besides, in addition to the functions of bridges, the bridges playing the roles of environmental and/or artistic structures become many, thereby the cases of using welding for the site joints increase. As the measure for rationalize bridge construction, it is to reduce steel weight and working costs for increasing profitability, and the progress of welding technology therefor has been observed. With regard to the manufacture of bridge portions in a factory, labor saving, automatization and robotization of in-house welding have been made, and bridge maintenance as well as pursuance of attaining the state of maintenance free are also important. The trend that the bridge load is becoming larger and enhancement of earthquake resistance are also important. Regarding steel frames, functionalization of steel, making steel very thick, various automatization of manufacturing, and pursuance of earthquake resistant safety are being made. 14 refs., 7 figs.

  19. Are doctors the structural weakness in the e-health building?

    Science.gov (United States)

    Hannan, T J; Celia, C

    2013-10-01

    Progressive evaluations by the Organization for Economic Co-operation and Development (OECD) demonstrate that health care is now or becoming unaffordable. This means nations must change the way they manage health care. The costly nature of health care in most nations, as a percentage of Gross Domestic Product (GDP) seems independent of the national funding models. Increasing evidence is demonstrating that the lack of involvement by clinicians (doctors, nurses, pharmacists, ancillary care and patients) in e-health projects is a major factor for the costly failures of many of these projects. The essential change in focus required to improve healthcare delivery using e-health technologies has to be on clinical care. To achieve this change clinicians must be involved at all stages of e-health implementations. From a clinicians perspective medicine is not a business. Our business is clinical medicine and e-health must be focussed on clinical decision making. This paper views the roles of physicians in e-health structural reforms.

  20. Seismic soil–structure interaction analysis of a nuclear power plant building founded on soil and in degraded concrete stiffness condition

    Energy Technology Data Exchange (ETDEWEB)

    Farahani, Reza V., E-mail: reza.farahani@rizzoassoc.com; Dessalegn, Tewodros M., E-mail: tewodros.dessalegn@rizzoassoc.com; Vaidya, Nishikant R., E-mail: nish.vaidya@rizzoassoc.com; Bazan-Zurita, Enrique, E-mail: enrique.bazanz@rizzoassoc.com

    2016-02-15

    Highlights: • Three dimensional finite element modeling of a Nuclear Power Plant (NPP) building founded on soil is described. • A simplified technique to consider degraded stiffness of concrete members in seismic analysis of NPP buildings is presented. • The effect of subsurface profiles on the seismic response of a NPP building is investigated. - Abstract: This study describes three-dimensional (3-D) finite element (FE) modeling and seismic Soil-Structure Interaction (SSI) analysis of a Nuclear Power Plant (NPP) Diesel Generator Building (DGB) that is founded on soil in degraded concrete stiffness condition. A new technique is presented that uses two horizontal and vertical FE models to consider the concrete stiffness reduction of NPP buildings subjected to orthogonal ground motion excitations, in which appropriate stiffness reduction factors, based on the input motion orientation, are applied. Seismic SSI analysis is performed for each model separately, and dynamic responses are calculated in the three global directions. The results of the analysis for the two FE models are then combined, using the square-root-of-the-sum-of-squares (SRSS) combination rule. A sensitivity analysis is also performed to investigate the subsurface profile effect on the In-Structure (acceleration) Response Spectra (ISRS) of the building when subjected to site-specific Foundation Input Response Spectra (FIRS) that exhibit high spectral amplifications in the high-frequency range. The sensitivity analysis considers three strain-compatible subsurface profiles that represent Lower-Bound (LB), Best-Estimate (BE), and Upper-Bound (UB) conditions at the DGB site. The sensitivity analysis results indicate that the seismic response of the DGB founded on soil highly depends on the subsurface profile; i.e., each of the LB, BE, and UB subsurface profiles can maximize building seismic response when subjected to FIRS that exhibit high spectral amplifications in the high-frequency range