Optimization of multi-layered metallic shield
International Nuclear Information System (INIS)
Research highlights: → We investigated the problem of optimization of a multi-layered metallic shield. → The maximum ballistic limit velocity is a criterion of optimization. → The sequence of materials and the thicknesses of layers in the shield are varied. → The general problem is reduced to the problem of Geometric Programming. → Analytical solutions are obtained for two- and three-layered shields. - Abstract: We investigate the problem of optimization of multi-layered metallic shield whereby the goal is to determine the sequence of materials and the thicknesses of the layers that provide the maximum ballistic limit velocity of the shield. Optimization is performed under the following constraints: fixed areal density of the shield, the upper bound on the total thickness of the shield and the bounds on the thicknesses of the plates manufactured from every material. The problem is reduced to the problem of Geometric Programming which can be solved numerically using known methods. For the most interesting in practice cases of two-layered and three-layered shields the solution is obtained in the explicit analytical form.
Optical properties of metallic multi-layer films
International Nuclear Information System (INIS)
Optical properties of multi-layer films consisting of alternating layers of two different metals are studied on the basis of the Maxwell equations and the Boltzmann transport theory. The influence of free-electron scattering at the film external surface and at the interfaces is taken into account and considered as a function of the electromagnetic field frequency and the structure modulation wavelength. Derived formulas for optical coefficients are valid at low frequencies, where the skin effect is nearly classical, as well as in the near-infrared, visible and ultraviolet spectral ranges, where the skin effect has the anomalous nature. It is shown that the obtained results are apparently dependent on the values of the scattering parameters. What is more, the oscillatory nature of analyzed spectra is observed, where the two oscillation periods may appear on certain conditions. The oscillations result from the electron surface and interface scattering and their amplitudes and periods depend on the boundary conditions for free-electron scattering. Finally, the application of the interference phenomenon in dielectric layers is proposed to obtain the enhancement of the non distinct details which can appear in optical spectra of metallic films. (author). 31 refs, 6 figs
Directory of Open Access Journals (Sweden)
Wenjiong Chen
2016-01-01
Full Text Available We present a design method for calculating and optimizing sound absorption coefficient of multi-layered porous fibrous metals (PFM in the low frequency range. PFM is simplified as an equivalent idealized sheet with all metallic fibers aligned in one direction and distributed in periodic hexagonal patterns. We use a phenomenological model in the literature to investigate the effects of pore geometrical parameters (fiber diameter and gap on sound absorption performance. The sound absorption coefficient of multi-layered PFMs is calculated using impedance translation theorem. To demonstrate the validity of the present model, we compare the predicted results with the experimental data. With the average sound absorption (low frequency range as the objective function and the fiber gaps as the design variables, an optimization method for multi-layered fibrous metals is proposed. A new fibrous layout with given porosity of multi-layered fibrous metals is suggested to achieve optimal low frequency sound absorption. The sound absorption coefficient of the optimal multi-layered fibrous metal is higher than the single-layered fibrous metal, and a significant effect of the fibrous material on sound absorption is found due to the surface porosity of the multi-layered fibrous.
Blood-Flow Modelling Along and Trough a Braided Multi-Layer Metallic Stent
Milisic, Vuk
2009-01-01
In this work we study the hemodynamics in a stented artery connected either to a collateral artery or to an aneurysmal sac. The blood flow is driven by the pressure drop. Our aim is to characterize the flow-rate and the pressure in the contiguous zone to the main artery: using boundary layer theory we construct a homogenized first order approximation with respect to epsilon, the size of the stent's wires. This provides an explicit expression of the velocity profile through and along the stent. The profile depends only on the input/output pressure data of the problem and some homogenized constant quantities: it is explicit. In the collateral artery this gives the flow-rate. In the case of the aneurysm, it shows that : (i) the zeroth order term of the pressure in the sac equals the averaged pressure along the stent in the main artery, (ii) the presence of the stent inverses the rotation of the vortex. Extending the tools set up in [Bonnetier et al, Adv. Math. Fluids, 2009, Milisic, Meth. Apl. Ann., 2009] we pro...
Effect of Liquid Media on the Formation of Multi-Layer Graphene-Synthesized Metal Particles.
Lee, Jung Woo; Kim, Tae-Yoo; Cho, Young Lae; Na, Young Il; Kim, Yoon Sik; Song, Young Il; Suh, Su Jeong
2015-11-01
We report a simple approach for the production of copper nanoparticles by a wire explosion process that creates different structures in deionized (DI) water versus isopropyl alcohol (IPA) liquid media. In DI water, copper nanoparticles (CNs) are formed, while multi-layer graphene-synthesized copper nanoparticles (MGCNs) with a high degree of graphitization are formed in the IPA liquid media. The nanoparticles have an average diameter ranging from 10 nm to 300 nm and a quasi-spherical morphology. The morphologies and sizes of nanoparticles formed via this method were characterized by high-resolution transmission electron microscopy (HRTEM), field-emission scattering electron microscopy (FESEM), and analysis of dynamic light scattering (DLS). The microstructures and chemical bonding of the nanoparticles were studied by X-ray diffraction (XRD), Raman spectra measurement, and X-ray photoelectron spectroscopy (XPS). This results show an easily reproducible way to synthesize metal-core nanoparticles with multi-layer graphene shells based onto the liquid media used during synthesis. These materials can be used in the field of energy storage and as additives in the near future. PMID:26726634
Design improvement of three-surface-multi-layered channel by reinforcing inner metal layer
International Nuclear Information System (INIS)
The three-surface-multi-layered channel has been proposed to reduce magnetohydrodynamic (MHD) pressure drop in a liquid lithium blanket for a future fusion reactor. The channel has three inner side coated with an insulating layer other than the first wall side. Furthermore, a thin vanadium alloy layer is placed on the insulating layer. Our previous study showed that the thin metal layer having a thickness less than 0.02 mm, which is too small to insure its structural integrity, is needed for the reduction of MHD pressure drop. In this study, therefore, we propose a new design for the channel, in which the thin vanadium alloy layer is partially reinforced by attaching reinforcing structure such as wires or columns on the insulating-layer side. As a first step, we conduct a three-dimensional MHD flow analysis by taking interval and length of the reinforcing structure as parameters. The results show that MHD pressure drop induced by the reinforcing structures does not show simple correlation with averaged electric conductance of thin metal layer with the reinforcing structures. Furthermore, a high velocity region appears in region of the first wall's side by changing the length of reinforcing structures. (author)
Directory of Open Access Journals (Sweden)
S. Griner
2007-01-01
Full Text Available Purpose: In the work, influence of chemical composition, as well as magnetic and electric properties on abilityof metallic glass screens for shielding of not ionizing electromagnetic fields were analyzed.Design/methodology/approach: The groups of amorphous metallic alloys with iron, iron and nickel and cobaltmatrix were selected for research. Samples of afore-mentioned metallic glasses were examined from the pointof view of structure, magnetic, electric and mechanical properties.Findings: There is possibility of utilization of metallic amorphous materials for screens of not ionizing,electromagnetic fields especially in range of broad-band multi-layers screens with high efficiency of shieldingin wide range of frequencies.Research limitations/implications: Very good magnetic properties and parallel low electric conductivity ofmetallic glasses are not enough for construction of multi-layer broadband screen. Therefore for constructingbroadband screen, which would attenuate much better in wider range of frequencies, we should seek solutionsin multi-layers systems consisting of metallic glass fabrics, layers of large conductivity materials and nonmagneticisolating layers. Problems of determining the number of layers, individual thickness of layer, materialsin relation to optimum costs of the multi-layers screen metallic glasses are unsolved.Practical implications: Attenuation of metallic glass screens show very high possibilities of metallic glasses insolution of problem of shielding electromagnetic fields.Originality/value: There are two general direction of improvement of suppression efficiency of electromagneticfields screens: research of new constructions of elastic screens, and investigation of new materials for screens joinhigher magnetic properties at high conductivity. In this second area, any possibilities exist in metallic nanomaterialsin form of tapes and nanocomposites consisting magnetic powders with amorphous and nanocrystalline
The Deformation of the Multi-Layered Panel of Sheet Metals Under Elevated Temperatures
Lee, Sang-Wook; Woo, Dong-Uk
A Molten Carbonate Fuel Cell (MCFC) stack consists of several layered unit cells. In each unit cell, the stiff structure of the separator plate contains the softer components, such as electrodes. When surface pressure acts on the stack over an extended period of time at elevated temperatures, the stiffness of the separator plate tends to degrade. Moreover, the demands for large electrode area (to increase the electric capacity of a unit cell) and thinner separator plates (to reduce weight) complicate the design of a separator plate with high stiffness. To evaluate the stiffness of the separator plate at elevated temperatures, we design and test a tiny, multi-layered separator plate specimen using a three-point bending tool. To determine the optimal structure of the separator plate, we investigate three design factors: angle, pitch and height. We adopt the Taguchi method to evaluate the experiments, and use finite element analysis to examine the experimental results. Based on these results, pitch is the most effective of these factors. As the pitch narrows, the stiffness of the separator plate increases. Therefore, we propose the pitch factor as a design criterion for the separator plate of the MCFC stack.
Institute of Scientific and Technical Information of China (English)
张佼; 孙宝德; 夏振海
2004-01-01
Systematical experiments were done at five temperature levels: 500 ℃, 630 ℃, 900 ℃, 1 000 ℃ and 1 100 ℃ to illuminate the layer structure of the multi-layered metal-intermetallic composites of Ni-Al system that were fabricated by a previously reported simple and cost-effective method. The analysis of back scattering photos and XRD examination of specimens reveal that the look like single compound layer is composed of several different components. The primary phase produced during reaction is Ni2 Al3 and there exists a like two-phase field between NiAl3 and Ni2 Al3. The high temperature phases like NiAl and Ni3 Al are also found at low temperature. The results indicate that the key driving force of in-situ reaction is not temperature, but the atom concentration.
Zamani, N.; Keshavarz, A.; Nadgaran, H.
2016-06-01
In this paper, we investigate the optical absorption coefficient of hybrid structure consisting of metal nano particle (MNP) coupled to multi-layer spherical quantum dot (MSQD). Energy eigenvalues and eigenfunctions of Schrödinger equation in this structure are obtained by using numerical solution (by the fourth-order Runge-Kutta method). The effect of MNP in the vicinity of MSQD is calculated by considering local field theory. Then the variation of optical absorption coefficient hybrid structure is calculated. The results show that the presence of MNP near MSQD enhances the optical absorption coefficient. Also, by changing the distance between MNP and MSQD and radius of MNP, variation of optical absorption coefficient and refractive index changes are introduced.
International Nuclear Information System (INIS)
This study investigates the preparation of Ge/TiO2 multi-layer films using a differential-pumping co-sputtering system (DPCS). This system has two chambers with different atmospheres, pure Ar for the Ge target and 0.5%O2 in Ar for the TiO2 ceramic target. The optical absorption spectra of the multi-layer films obviously shift to visible and near-infrared regions with increasing Ge layer thickness, while keeping O/Ti composition ratios of 2.3 ± 0.1 in TiO2. X-ray diffraction results indicate that the TiO2 layer forms a single-phase anatase structure in the multi-layer films. X-ray photoelectron spectroscopy also indicates that metallic Ge is dominant in the multi-layer film with negligible Ge-oxide. Therefore, DPCS provides a multi-layer film with a single-phase anatase structure in the TiO2 layer and a dominant metallic element in the Ge layer. - Highlights: • Single-phase anatase structure and dominant metallic Ge in Ge/TiO2 multi-layer films are prepared. • We employ a differential pumping co-sputtering system. • The optical absorption spectra shift to visible and near-infrared regions with increasing Ge layer thickness. • X-ray diffraction results indicate that the TiO2 layer forms a single-phase anatase structure. • X-ray photoelectron spectroscopy also indicates that metallic Ge is dominant in the Ge layer
叠层金属薄板材料的冲裁特性研究%Research on the Characteristics of Multi-layer Sheet Metal Blanking
Institute of Scientific and Technical Information of China (English)
槐建明; 樊瑜瑾; 郭波江
2012-01-01
There are lots of differences between single-layer metal plate and multi-layer sheet metal in blanking. By comparing those differences, this paper analyzed the stress-strain state of the element found in the deformation region of blanking, and then pointed out that the middle layers of multi-layer sheet are in the three-stress state, showing great plasticity. According to the characteristics an experiment has proposed, through decreasing the clearance between punch and die reasonably, the hydrostatic pressure can be improved in the deforming zone and the cracks can be restrained, so the blanking is deformed in the plastic shear, in order to improve the blanking quality. Further, taking the multi-layer bus punching experiment to confirm the theory, we get the consistent conclusion that multi-layer sheet metal blanking is required smaller clearance than the same thickness of single-layer metal plate. In order to get better blanking quality, a correction factor about 0. 4 should multiply the formula of blanking clearance to determine the multi-layer sheet metal blanking clearance.%在冲裁分离过程中,单层与叠层金属板材存在很大的差异.通过对比2者的不同特点,选取并分析微元体的应力应变状态,发现在叠层冲裁过程中,变形区内中间层的材料处在3向压应力状态,表现出很强的可塑性.分析冲裁中各因素对应力状态的影响发现,合理地减小凸模与凹模的间隙可以提高变形区的静水压,抑制裂纹的产生,使冲裁过程控制在塑剪变形阶段.以叠层母线冲孔为例来验证理论分析,试验结果与分析一致,叠层冲裁比同厚度单层冲裁所要求的模具间隙更小,其值取在普通冲裁间隙经验公式的基础上乘以0.4左右的修正系数为宜.
Kim, Byoung-Joon; Shin, Hae-A.-Seul; Lee, Ji-Hoon; Joo, Young-Chang
2016-06-01
The electrical reliability of a multi-layer metal film on a polymer substrate during cyclic inner bending and outer bending is investigated using a bending fatigue system. The electrical resistance of a Cu film on a polymer substrate during cyclic outer bending increases due to fatigue damage formation, such as cracks and extrusion. Cyclic inner bending also leads to fatigue damage and a similar increase in the electrical resistance. In a sample having a NiCr under-layer, however, the electrical resistance increases significantly during outer bending but not during inner bending mode. Cross-sectional observations reveal that brittle cracking in the hard under-layer results in different fatigue behaviors according to the stress mode. By applying an Al over-layer, the fatigue resistance is improved during both outer bending and inner bending by suppressing fatigue damage formation. The effects of the position, materials, and thickness of the inter-layer on the electrical reliability of a multi-layer sample are also investigated. This study can provide meaningful information for designing a multi-layer structure under various mechanical deformations including tensile and compressive stress.
GaN metal-semiconductor-metal UV sensor with multi-layer graphene as Schottky electrodes
Lee, Chang-Ju; Kang, Sang-Bum; Cha, Hyeon-Gu; Won, Chul-Ho; Hong, Seul-Ki; Cho, Byung-Jin; Park, Hongsik; Lee, Jung-Hee; Hahm, Sung-Ho
2015-06-01
We fabricated a GaN-based metal-semiconductor-metal (MSM)-type UV sensor using a multilayer graphene as transparent Schottky electrodes. The fabricated GaN MSM UV sensor showed a high photo-to-dark current contrast ratio of 3.9 × 105 and a UV-to-visible rejection ratio of 1.8 × 103 at 7 V. The as-fabricated GaN MSM UV sensor with graphene electrodes has a low bias dependence of maximum photoresponsivity and a noise-like response at a visible wavelength in the 500 nm region. These problems were successfully solved by treatment with a buffered oxide etcher (BOE), and the photoresponse characteristics of the fabricated GaN MSM UV sensor after the treatment were better than those before the treatment.
Bökstedt, Marcel
2016-01-01
We study a novel type of braid groups on a closed orientable surface $\\Sigma$. These are fundamental groups of certain manifolds that are hybrids between symmetric products and configuration spaces of points on $\\Sigma$; a class of examples arises naturally in gauge theory, as moduli spaces of vortices in toric fibre bundles over $\\Sigma$. The elements of these braid groups, which we call divisor braids, have coloured strands that are allowed to intersect according to rules specified by a graph $\\Gamma$. In situations where there is more than one strand of each colour, we show that the corresponding braid group admits a metabelian presentation as a central extension of the free Abelian group $H_1(\\Sigma;\\mathbb{Z})^{\\oplus r}$, where $r$ is the number of colours, and describe its Abelian commutator. This computation relies crucially on producing a link invariant (of closed divisor braids) in the three-manifold $S^1 \\times \\Sigma $ for each graph $\\Gamma$. We also describe the von Neumann algebras associated t...
Braided Clifford algebras as braided quantum groups
Durdevic, M
1995-01-01
The paper deals with braided Clifford algebras, understood as Chevalley-Kahler deformations of braided exterior algebras. It is shown that Clifford algebras based on involutive braids can be naturally endowed with a braided quantum group structure. Basic group entities are constructed explicitly.
Directory of Open Access Journals (Sweden)
Hideo Honma
2012-10-01
Full Text Available (1 The photo-induced solubility and positive-tone direct photo-patterning of iron, copper and lanthanides chelated with 4-(2-nitrobenzyloxycarbonylcatechol (NBOC or 4-(6-nitroveratryloxycarbonylcatechol (NVOC was investigated. Photo-patterning of iron, copper, cerium, samarium, europium, terbium, dysprosium, holmium, erbium and lutetium complexes was accomplished. Continuous films were formed by the pyrolysis of metal complex films at 500 °C. (2 Based on the difference in the photo-reaction excitation wavelength profile of NBOC and NVOC complexes, a short and simple method for simultaneous micro-patterning of two independent films on each side of a transparent glass substrate was developed. Using the developed procedure, indium tin oxide and/or titanium oxide films were formed on each side of a quartz substrate without use of resist or etching.
Eddy Current System for Detection of Cracking Beneath Braiding in Corrugated Metal Hose
Wincheski, Buzz; Simpson, John; Hall, George
2008-01-01
In this paper an eddy current system for the detection of partially-through-the-thickness cracks in corrugated metal hose is presented. Design criteria based upon the geometry and conductivity of the part are developed and applied to the fabrication of a prototype inspection system. Experimental data are used to highlight the capabilities of the system and an image processing technique is presented to improve flaw detection capabilities. A case study for detection of cracking damage in a space shuttle radiator retract flex hoses is also presented.
EDDY CURRENT SYSTEM FOR DETECTION OF CRACKING BENEATH BRAIDING IN CORRUGATED METAL HOSE
International Nuclear Information System (INIS)
In this paper an eddy current system for the detection of partially-through-the-thickness cracks in corrugated metal hose is presented. Design criteria based upon the geometry and conductivity of the part are developed and applied to the fabrication of a prototype inspection system. Experimental data are used to highlight the capabilities of the system and an image processing technique is presented to improve flaw detection capabilities. A case study for detection of cracking damage in a space shuttle radiator retract flex hoses is also presented.
2002-01-01
On October 13, 2000, the Expedition 3 crew of the International Space Station, high over Tibet, took this interesting photo of the Brahmaputra River. This mighty Asian river carves a narrow west-east valley between the Tibetan Plateau to the north and the Himalaya Mountains to the south, as it rushes eastward for more than 1500 km in southwestern China. This 15-km stretch is situated about 35 km south of the ancient Tibetan capital of Lhasa where the river flow becomes intricately braided as it works and reworks its way through extensive deposits of erosional material. This pattern is indicative of a combination heavy sediment discharge from tributaries and reduction of the river's flow from either a change in gradient or perhaps even climate conditions over the watershed. The light color of the deposits and the milky color of the water is attributed to presence of glacial 'flour,' the fine material created by erosion from glaciers. Besides erosion by water and ice, this scene also depicts features created by wind. Note the delicate field of dunes on the alluvial fan toward the right edge of the image. The riverbed here is at an elevation of over 3,500 m, and with the long west-east extent of this barren valley, strong, persistent westerly winds also move and shape these deposits. Photos such as this one bring immediate visual understanding and appreciation of natural processes in some of the most remote locations on Earth. Image ISS003-E-6632, was provided by the Earth Sciences and Image Analysis Laboratory at Johnson Space Center. Additional images taken by astronauts and cosmonauts can be viewed at the NASA-JSC Gateway to Astronaut Photography of Earth.
Multi-Layer E-Textile Circuits
Dunne, Lucy E.; Bibeau, Kaila; Mulligan, Lucie; Frith, Ashton; Simon, Cory
2012-01-01
Stitched e-textile circuits facilitate wearable, flexible, comfortable wearable technology. However, while stitched methods of e-textile circuits are common, multi-layer circuit creation remains a challenge. Here, we present methods of stitched multi-layer circuit creation using accessible tools and techniques.
Czech Academy of Sciences Publication Activity Database
Borisova, A.; Bondar, B.; Machulyansky, A.; Rodionov, M.; Yakimenko, Y.; Bovtun, Viktor; Kempa, Martin
New York: IEEE, 2014, s. 164-167. ISBN 978-1-4799-4581-8. [IEEE 34th International Scientific Conference on Electronics and Nanotechnology (ELNANO 2014). Kyiv (UA), 15.04.2014-18.04.2014] R&D Projects: GA ČR GAP204/12/0232 Institutional support: RVO:68378271 Keywords : metal-dielectric composites * conductivity * microwave absorption * reflection and transmission coefficients * electrodynamic simulation Subject RIV: BM - Solid Matter Physics ; Magnetism
Hamilton, Linus
2014-01-01
Braid is a 2008 puzzle game centered around the ability to reverse time. We show that Braid can simulate an arbitrary computation. Our construction makes no use of Braid's unique time mechanics, and therefore may apply to many other video games. We also show that a plausible "bounded" variant of Braid lies within 2-EXPSPACE. Our proof relies on a technical lemma about Turing machines which may be of independent interest. Namely, define a braidlike Turing machine to be a Turing machine that, w...
van den Berg, J. B.; Ghrist, R.; Vandervorst, R. C.; Wójcik, W.
2015-09-01
Area-preserving diffeomorphisms of a 2-disc can be regarded as time-1 maps of (non-autonomous) Hamiltonian flows on R / Z ×D2. The periodic flow-lines define braid (conjugacy) classes, up to full twists. We examine the dynamics relative to such braid classes and define a new invariant for such classes, the BRAID FLOER HOMOLOGY. This refinement of Floer homology, originally used for the Arnol'd Conjecture, yields a Morse-type forcing theory for periodic points of area-preserving diffeomorphisms of the 2-disc based on braiding. Contributions of this paper include (1) a monotonicity lemma for the behavior of the nonlinear Cauchy-Riemann equations with respect to algebraic lengths of braids; (2) establishment of the topological invariance of the resulting braid Floer homology; (3) a shift theorem describing the effect of twisting braids in terms of shifting the braid Floer homology; (4) computation of examples; and (5) a forcing theorem for the dynamics of Hamiltonian disc maps based on braid Floer homology.
Roy, Sutanu
2016-01-01
We propose a general theory of braided quantum groups in the C*-algebraic framework. More precisely, we construct braided quantum groups using manageable braided multiplicative unitaries over a regular C*-quantum group. We show that braided C*-quantum groups are equivalent to C*-quantum groups with projection.
Reverse engineering of multi-layer films
Directory of Open Access Journals (Sweden)
Effendi Widjaja
2011-03-01
Full Text Available This contribution introduces the combined application of Raman microscopy and band-target entropy minimization (BTEM in order to successfully reverse-engineer a multi-layer packaging material. Three layers are identified, namely, polyethylene, a paper and talc layer (with two distinct cellulose forms, and a poly-styrene co-polymer composite containing anatase and calcite. This rapid and non-destructive approach provides a unique opportunity for the assessment of multi-layer composites, including the constitution of the additives present.
Preparation of multi-layer laser targets
International Nuclear Information System (INIS)
The author describes the preparation of copper- or gold-Formvar-aluminum-Formvar multi-layer laser targets. First, copper or gold is deposited on a piece of glass, then it is covered with the Formvar film. After the copper or gold layer, together with the Formvar film, is stripped off and fitted in, aluminum is deposited. Because the Formvar is vaporized in the vaporizing chamber only once, the obtained multi-layer target is of high quality and meets the requirements for practical use
Multi-layered breathing architectural envelope
DEFF Research Database (Denmark)
Lund Larsen, Andreas; Foged, Isak Worre; Jensen, Rasmus Lund
2014-01-01
A multi layered breathing envelope is developed as a method of natural ventilation. The two main layers consist of mineral wool and air permeable concrete. The mineral wool works as a dynamic insulation and the permeable concrete as a heat recovery system with a high thermal mass for heat storage...
Decoupling braided tensor factors
International Nuclear Information System (INIS)
It is shown that the braided tensor product algebra of two module algebras A1, A2 of a quasitriangular Hopf algebra is equal to the ordinary tensor product algebra of A1 with a subalgebra isomorphic to A2 and commuting with A1. As applications of the theorem the braided tensor product algebras of two or more quantum group covariant quantum space or deformed Heisenberg algebras are considered
Network Composition from Multi-layer Data
Lerman, Kristina; Yan, Xiaoran
2016-01-01
It is common for people to access multiple social networks, for example, using phone, email, and social media. Together, the multi-layer social interactions form a "integrated social network." How can we extend well developed knowledge about single-layer networks, including vertex centrality and community structure, to such heterogeneous structures? In this paper, we approach these challenges by proposing a principled framework of network composition based on a unified dynamical process. Mathematically, we consider the following abstract problem: Given multi-layer network data and additional parameters for intra and inter-layer dynamics, construct a (single) weighted network that best integrates the joint process. We use transformations of dynamics to unify heterogeneous layers under a common dynamics. For inter-layer compositions, we will consider several cases as the inter-layer dynamics plays different roles in various social or technological networks. Empirically, we provide examples to highlight the usef...
Mathematical Formulation of Multi-Layer Networks
De Domenico, Manlio; Cozzo, Emanuele; Kivelä, Mikko; Moreno, Yamir; Porter, Mason A; Gòmez, Sergio; Arenas, Alex
2013-01-01
A network representation is useful for describing the structure of a large variety of complex systems. However, most real and engineered systems have multiple subsystems and layers of connectivity, and the data produced by such systems is very rich. Achieving a deep understanding of such systems necessitates generalizing "traditional" network theory, and the newfound deluge of data now makes it possible to test increasingly general frameworks for the study of networks. In particular, although adjacency matrices are useful to describe traditional single-layer networks, such a representation is insufficient for the analysis and description of multiplex and time-dependent networks. One must therefore develop a more general mathematical framework to cope with the challenges posed by multi-layer complex systems. In this paper, we introduce a tensorial framework to study multi-layer networks, and we discuss the generalization of several important network descriptors and dynamical processes ---including degree centr...
Analysis of multi-layer polymer films
Directory of Open Access Journals (Sweden)
Paulette Guillory
2009-04-01
Full Text Available Polymer multi-layer films are used in a variety of industries. It is important both to the manufacturers of polymer films and to the industries using these films that the quality and composition be strictly controlled. The confocal analysis and high spatial resolution of Raman microscopy make this technique ideal for identifying the source and identity of defects and inclusions in polymer films.
Silicon-on-Insulating Multi-Layers for Total-Dose Irradiation Hardness
Institute of Scientific and Technical Information of China (English)
ZHANG En-Xia; YI Wan-Bing; LIU Xiang-Hua; CHEN Meng; LIU Zhong-Li; Wang Xi
2004-01-01
@@ Silicon-on-insulating multi-layer (SOIM) materials were fabricated by co-implantation of oxygen and nitrogen ions with different energies and doses. The multilayer microstructure was investigated by cross-sectional transmission electron microscopy. P-channel metal-oxide-semiconductor (PMOS) transistors and metal-semiconductorinsulator-semiconductor (MSIS) capacitors were produced by these materials.
Temperature distribution in laser-clad multi-layers
International Nuclear Information System (INIS)
Results of temperature distribution modeling for multi-layer structures prepared by direct laser remelting of metal powders in an Ar environment were numerically obtained and compared with experimental data. Powders of bronze B10 and stellite SF6 alloys and also base plates of S235JR steel were taken as sample materials. In the experiment a 1.5 kW cw CO2 laser, equipped with a multi-stream nozzle capable of delivering metal powder at a rate of up to 0.2 g/s coaxially with the laser beam, was used. Dimensions of the melted zone and its position relative to the base were obtained from calculation and agreed with the microstructure observation of the sample cross-sections. The model revealed that isotherms at 1020 and 1350 deg. C penetrate the interfaces to a depth of about 5-10% of the individual layer height for B10 and SF6, respectively. This was confirmed by inspection in a scanning electron microscope (SEM) and also by a depth-dependent X-ray energy-dispersive spectroscopy (XEDS) measurement of the main chemical components of multi-layers, i.e. Fe, Co, Ni (SF6) and Fe, Cu, Sn (B10). Also the cooling rates indicated agreement between modeling and experiment. This allows us to conclude that the model can be applied for preselecting the process parameters
Multi-Layered Neural Networks Infer Fundamental Stellar Parameters
Verma, Kuldeep; Bhattacharya, Jishnu; Antia, H M; Krishnamurthy, Ganapathy
2016-01-01
The advent of space-based observatories such as CoRoT and Kepler has enabled the testing of our understanding of stellar evolution on thousands of stars. Evolutionary models typically require five input parameters, the mass, initial Helium abundance, initial metallicity, mixing-length (assumed to be constant over time) and the age to which the star must be evolved. These parameters are also very useful in characterizing the associated planets and in studying galactic archaeology. How to obtain the parameters from observations rapidly and accurately, specifically in the context of surveys of thousands of stars, is an outstanding question, one that has eluded straightforward resolution. For a given star, we typically measure the effective temperature and surface metallicity spectroscopically and low-degree oscillation frequencies through space observatories. Here we demonstrate that statistical learning, using multi-layered neural networks, is successful in determining the evolutionary parameters based on spect...
Analysis of multi-layer ERBS spectra
Energy Technology Data Exchange (ETDEWEB)
Marmitt, G.G. [Atomic and Molecular Physics Laboratories, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Instituto de Fisica da Universidade Federal do Rio Grande do Sul, Avenida Bento Goncalves 9500, 91501-970 Porto Alegre, RS (Brazil); Rosa, L.F.S. [Instituto de Fisica da Universidade Federal do Rio Grande do Sul, Avenida Bento Goncalves 9500, 91501-970 Porto Alegre, RS (Brazil); Nandi, S.K. [Electronic Materials Engineering Department, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Research School of Astronomy and Astrophysics, The Australian National University, Canberra, ACT 2611 (Australia); Department of Physics, University of Chittagong, Chittagong 4331 (Bangladesh); Vos, M., E-mail: maarten.vos@anu.edu.au [Atomic and Molecular Physics Laboratories, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia)
2015-07-15
Highlights: • Electron Rutherford backscattering (ERBS) spectra are presented. • The spectra are fitted based on physical meaningful quantities. • Very consistent results are obtained for spectra taken under different conditions. • This establishes that ERBS can be used to measure film thicknesses. - Abstract: A systematic way of analysis of multi-layer electron Rutherford backscattering spectra is described. The approach uses fitting in terms of physical meaningful parameters. Simultaneous analysis then becomes possible for spectra taken at different incoming energies and measurement geometries. Examples are given to demonstrate the level of detail that can be resolved by this technique.
MULTI-LAYER GRID REFINEMENT METHOD
Directory of Open Access Journals (Sweden)
TSUN-ZEE MAI
2012-07-01
Full Text Available The uniform grid scheme has been widely used to solve a partial differential equation. Due to the extreme large linear systems generated by the uniform grid scheme, a lot of computation time is required. To improve the efficiency of the uniform grid scheme, a more economical method is desirable. In this paper, we propose a multi-layer grid refinement method for solving a partial different equation over a rectangular domain with Dirichlet boundary conditions. Numerical experiments demonstrate that the efficiency has been improved significantly, and the accuracy is satisfactory.
Design for reliability of multi-layer stretchable interconnects
International Nuclear Information System (INIS)
In this investigation, the electrical performance and reliability of multi-layer stretchable metal interconnects are evaluated using numerical simulations and experimental analysis. The numerical results show that the bi-layer design of stretchable interconnects have similar mechanics when compared to single layer interconnect structures. In contrast, interconnects configured in an in-plane stacked arrangement exhibit increased equivalent plastic strain during elongation, and consequently support less stretching. Our experimental results support these numerical findings. Maximum stretchability approaches ∼150% elongation for single layer and bi-layer interconnects. In addition, fatigue experiments at 60% elongation show that the bi-layer design of stretchable interconnects have life cycles three orders of magnitude higher than the in-plane stacked arrangement of stretchable interconnects. (paper)
Process Issues for a Multi-Layer Microelectrofluidic Platform
Ng, S -H; Tjeung, R -T; De Rooij, N
2007-01-01
We report on the development of some process capabilities for a polymer-based, multi-layer microelectrofluidic platform, namely: the hot embossing process, metallization on polymer and polymer bonding. Hot embossing experiments were conducted to look at the effects of load applied, embossing temperature and embossing time on the fidelity of line arrays representing micro channels. The results revealed that the embossing temperature is a more sensitive parameter than the others due to its large effect on the polymer material's viscoelastic properties. Dynamic mechanical analysis (DMA) on polymethyl methacrylate (PMMA) revealed a steep glass transition over a 20 oC range, with the material losing more than 95 % of its storage modulus. The data explained the hot embossing results which showed large change in the embossed channel dimensions when the temperature is within the glass transition range. It was demonstrated that the micro-printing of silver epoxy is a possible low-cost technique in the mass production ...
Investigation of microstructure and mechanical properties of multi-layer Cr/Cr2O3 coatings
International Nuclear Information System (INIS)
Single and multi-layer Cr/Cr2O3 coatings were deposited by reactive magnetron sputtering with the total thickness of 7 μm on steel substrates. X-ray diffraction analysis showed that single and multi-layer Cr/Cr2O3 coatings have different preferred crystal orientations. Columnar microstructure was detected by transmission electron microscopy both in metal chromium and ceramic chromium oxide layers. Grain size increased with the coating thickness. The value of single and multi-layer coating's fracture toughness is between 4 and 6 MPa.m1/2 measured with the Berkovich tip indentation, and it is between 2.8 and 3.9 MPa.m1/2 when measured with the Vickers indenter. The adhesion is about 192.1 and 246.7 J/m2 for single and multi-layer coatings, respectively
Free braided differential calculus, braided binomial theorem and the braided exponential map
Majid, S
1993-01-01
Braided differential operators $\\del^i$ are obtained by differentiating the addition law on the braided covector spaces introduced previously (such as the braided addition law on the quantum plane). These are affiliated to a Yang-Baxter matrix $R$. The quantum eigenfunctions $\\exp_R(\\vecx|\\vecv)$ of the $\\del^i$ (braided-plane waves) are introduced in the free case where the position components $x_i$ are totally non-commuting. We prove a braided $R$-binomial theorem and a braided-Taylors theorem $\\exp_R(\\veca|\\del)f(\\vecx)=f(\\veca+\\vecx)$. These various results precisely generalise to a generic $R$-matrix (and hence to $n$-dimensions) the well-known properties of the usual 1-dimensional $q$-differential and $q$-exponential. As a related application, we show that the q-Heisenberg algebra $px-qxp=1$ is a braided semidirect product $\\C[x]\\cocross \\C[p]$ of the braided line acting on itself (a braided Weyl algebra). Similarly for its generalization to an arbitrary $R$-matrix.
Gonzalez-Meneses, Juan
2010-01-01
These are Lecture Notes of a course given by the author at the French-Spanish School "Tresses in Pau", held in Pau (France) in October 2009. It is basically an introduction to distinct approaches and techniques that can be used to show results in braid groups. Using these techniques we provide several proofs of well known results in braid groups, namely the correctness of Artin's presentation, that the braid group is torsion free, or that its center is generated by the full twist. We also recall some solutions of the word and conjugacy problems, and that roots of a braid are always conjugate. We also describe the centralizer of a given braid. Most proofs are classical ones, using modern terminology. I have chosen those which I find simpler or more beautiful.
Multi-layer switched reluctance motor to reduce torque ripple
International Nuclear Information System (INIS)
A new multi-layer switched reluctance motor (MSRM) having a high starting torque capability with reduced torque ripple and acoustic noise is presented. Measured data and the results of numerical analysis are given to evaluate the motor structure. In the numerical analysis, due to the highly nonlinear nature of the motor, finite element analysis (FEA) is employed. A prototype multi-layer SRM is built and tested in the experimental studies. The obtained test and simulation results show that the multi-layer motor structure has a smooth torque profile with high starting torque and less acoustic noise
Optical Properties of Multi-Layered Insulation
Rodriguez, Heather M.; Abercromby, Kira J.; Barker, Edwin
2007-01-01
Multi-layer insulation, MLI, is a material used on rocket bodies and satellites mainly for thermal insulation. MLI can be comprised of a variety of materials, layer numbers, and dimensions based on its purpose. A common composition of MLI consists of outer facing copper-colored Kapton with an aluminized backing for the top and bottom layers and the middle consisting of alternating layers of DARCON or Nomex netting with aluminized Mylar. If this material became separated from the spacecraft or rocket body its orbit would vary greatly in eccentricity due to its high area to mass (A/m) and susceptibility to solar radiation pressure perturbations. Recently a debris population was found with high A/m, which could be MLI. Laboratory photometric measurements of one intact piece and three different layers of MLI is presented in an effort to predict the characteristics of a MLI light curve and aid in identifying the source of the new population. For this paper, the layers used will be consistent with the common MLI mentioned in the above paragraph. Using a robotic arm, the piece was rotated from 0-360 degrees in one degree increments along the object s longest axis. Laboratory photometric data was recorded with a CCD camera using various filters (Johnson B, Johnson V and Bessell R). The measurements were taken at an 18 degree (light-object-camera) phase angle. As expected, the MLI pieces showed characteristics similar to a bimodal magnitude plot of a flat plate, but with more photometric features, dependant upon the layer of MLI. Time exposures varied from piece to piece such that the amount of pixels saturated would be minimal. In addition to photometric laboratory measurements, laboratory spectral measurements are shown for the same MLI samples. Spectral data will be combined to match the wavelength region of photometric data so a measure of truth can be established for the photometric measurements. Spectral data shows a strong absorption feature near 4800 angstroms
Multi-layer Far-Infrared Component Technology Project
National Aeronautics and Space Administration — This Phase I SBIR will demonstrate the feasibility of a process to create multi-layer thin-film optics for the far-infrared/sub-millimeter wave spectral region. The...
Radio-transparent multi-layer insulation for radiowave receivers
International Nuclear Information System (INIS)
In the field of radiowave detection, enlarging the receiver aperture to enhance the amount of light detected is essential for greater scientific achievements. One challenge in using radio transmittable apertures is keeping the detectors cool. This is because transparency to thermal radiation above the radio frequency range increases the thermal load. In shielding from thermal radiation, a general strategy is to install thermal filters in the light path between aperture and detectors. However, there is difficulty in fabricating metal mesh filters of large diameters. It is also difficult to maintain large diameter absorptive-type filters in cold because of their limited thermal conductance. A technology that maintains cold conditions while allowing larger apertures has been long-awaited. We propose radio-transparent multi-layer insulation (RT-MLI) composed from a set of stacked insulating layers. The insulator is transparent to radio frequencies, but not transparent to infrared radiation. The basic idea for cooling is similar to conventional multi-layer insulation. It leads to a reduction in thermal radiation while maintaining a uniform surface temperature. The advantage of this technique over other filter types is that no thermal links are required. As insulator material, we used foamed polystyrene; its low index of refraction makes an anti-reflection coating unnecessary. We measured the basic performance of RT-MLI to confirm that thermal loads are lowered with more layers. We also confirmed that our RT-MLI has high transmittance to radiowaves, but blocks infrared radiation. For example, RT-MLI with 12 layers has a transmittance greater than 95% (lower than 1%) below 200 GHz (above 4 THz). We demonstrated its effects in a system with absorptive-type filters, where aperture diameters were 200 mm. Low temperatures were successfully maintained for the filters. We conclude that this technology significantly enhances the cooling of radiowave receivers, and is
Radio-transparent multi-layer insulation for radiowave receivers
Choi, J.; Ishitsuka, H.; Mima, S.; Oguri, S.; Takahashi, K.; Tajima, O.
2013-11-01
In the field of radiowave detection, enlarging the receiver aperture to enhance the amount of light detected is essential for greater scientific achievements. One challenge in using radio transmittable apertures is keeping the detectors cool. This is because transparency to thermal radiation above the radio frequency range increases the thermal load. In shielding from thermal radiation, a general strategy is to install thermal filters in the light path between aperture and detectors. However, there is difficulty in fabricating metal mesh filters of large diameters. It is also difficult to maintain large diameter absorptive-type filters in cold because of their limited thermal conductance. A technology that maintains cold conditions while allowing larger apertures has been long-awaited. We propose radio-transparent multi-layer insulation (RT-MLI) composed from a set of stacked insulating layers. The insulator is transparent to radio frequencies, but not transparent to infrared radiation. The basic idea for cooling is similar to conventional multi-layer insulation. It leads to a reduction in thermal radiation while maintaining a uniform surface temperature. The advantage of this technique over other filter types is that no thermal links are required. As insulator material, we used foamed polystyrene; its low index of refraction makes an anti-reflection coating unnecessary. We measured the basic performance of RT-MLI to confirm that thermal loads are lowered with more layers. We also confirmed that our RT-MLI has high transmittance to radiowaves, but blocks infrared radiation. For example, RT-MLI with 12 layers has a transmittance greater than 95% (lower than 1%) below 200 GHz (above 4 THz). We demonstrated its effects in a system with absorptive-type filters, where aperture diameters were 200 mm. Low temperatures were successfully maintained for the filters. We conclude that this technology significantly enhances the cooling of radiowave receivers, and is
Reducible braids and Garside theory
Gonzalez-Meneses, Juan
2010-01-01
We show that reducible braids which are, in a Garside-theoretical sense, as simple as possible within their conjugacy class, are also as simple as possible in a geometric sense. More precisely, if a braid belongs to a certain subset of its conjugacy class which we call the stabilized set of sliding circuits, and if it is reducible, then its reducibility is geometrically obvious: it has a round or almost round reducing curve. Moreover, for any given braid, an element of its stabilized set of sliding circuits can be found using the well-known cyclic sliding operation. This leads to a polynomial time algorithm for deciding the Nielsen-Thurston type of any braid, modulo one well-known conjecture on the speed of convergence of the cyclic sliding operation.
Cable Braid Electromagnetic Penetration Model.
Energy Technology Data Exchange (ETDEWEB)
Warne, Larry K. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Langston, William L. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Basilio, Lorena I. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Johnson, W. A. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
2015-06-01
The model for penetration of a wire braid is rigorously formulated. Integral formulas are developed from energy principles and reciprocity for both self and transfer immittances in terms of potentials for the fields. The detailed boundary value problem for the wire braid is also setup in a very efficient manner; the braid wires act as sources for the potentials in the form of a sequence of line multipoles with unknown coefficients that are determined by means of conditions arising from the wire surface boundary conditions. Approximations are introduced to relate the local properties of the braid wires to a simplified infinite periodic planar geometry. This is used in a simplified application of reciprocity to be able to treat nonuniform coaxial geometries including eccentric interior coaxial arrangements and an exterior ground plane.
Presentations of Graph Braid Groups
Farley, Daniel; Sabalka, Lucas
2009-01-01
Let G be a graph. The (unlabeled) configuration space of n points on G is the space of all n-element subsets of G. The fundamental group of such a configuration space is called a graph braid group. We use a version of discrete Morse theory to compute presentations of all graph braid groups, for all finite connected graphs G and all natural numbers n.
Duality principle and braided geometry
Majid, S
1994-01-01
We give an overview of a new kind symmetry in physics which exists between observables and states and which is made possible by the language of Hopf algebras and quantum geometry. It has been proposed by the author as a feature of Planck scale physics. More recent work includes corresponding results at the semiclassical level of Poisson-Lie groups and at the level of braided groups and braided geometry.
Optical Properties of Multi-Layered Insulation
Rodriguez, H.; Abercromby, K.; Mulrooney, M.; Barker, E.
Multi-layer insulation (MLI) is a material used on rocket bodies and satellites primarily for thermal insulation. MLI is comprised of a variety of materials, layer numbers, and dimensions to satisfy specific design requirements. Typically, it is a sandwich of outward facing copper-colored Kapton layers with inward facing aluminized backing. The inner layers consist of alternating DACRON or Nomex netting and aluminized Mylar. From an orbital mechanics perspective, if this material becomes separated from a spacecraft or rocket body, its orbit will vary greatly in eccentricity due to both its high area-to-mass ratio (A/m) and its susceptibility to solar radiation pressure perturbations. Recently, a debris population was found with high A/m which could be MLI. Laboratory photometric measurements of one intact piece and three different layers of MLI are presented in an effort to ascertain the characteristics of MLI light curves and aid in identifying the source of the new population. For this paper, the layers used will be consistent with the aforementioned common MLI. Using a robotic arm, the piece was rotated from 0-360 degrees in 10? increments along the objects longest axis. Laboratory photometric data was recorded with a CCD camera and a 300 W Xenon arc light source selected to approximate the solar spectrum. The measurements were taken in white light and using various filters (Johnson Blue (B), Visible (V), and Bessell Red (R)), all taken at an 18 degree (light-object-camera) phase angle selected to closely match typical GEO observations which follow the anti-solar point. As expected, the MLI pieces exhibited characteristics similar to a bimodal magnitude plot of a flat plate, but with photometric features dependent upon the layer composition. To minimize highlight saturation (and consequent loss of intensity information), exposure times were selected empirically based on layer type and filter. In addition to photometric laboratory measurements, laboratory
Enhanced Multi-Layer Fatigue-Analysis Approach for Unbonded Flexible Risers
Institute of Scientific and Technical Information of China (English)
杨和振; 姜豪; 杨启
2014-01-01
This paper proposes an enhanced approach for evaluating the fatigue life of each metallic layer of unbonded flexible risers. Owing to the complex structure of unbonded flexible risers and the nonlinearity of the system, particularly in the critical touchdown zone, the traditional method is insufficient for accurately evaluating the fatigue life of these risers. The main challenge lies in the transposition from global to local analyses, which is a key stage for the fatigue analysis of flexible pipes owing to their complex structure. The new enhanced approach derives a multi-layer stress-decomposition method to meet this challenge. In this study, a numerical model validated experimentally is used to demonstrate the accuracy of the stress-decomposition method. And a numerical case is studied to validate the proposed approach. The results demonstrate that the multi-layer stress-decomposition method is accurate, and the fatigue lives of the metallic layers predicted by the enhanced multi-layer analysis approach are rational. The proposed fatigue-analysis approach provides a practical and reasonable method for predicting fatigue life in the design of unbonded flexible risers.
Mechanical properties of braided commingled glass/polypropylene composites
International Nuclear Information System (INIS)
Fibre reinforced plastics (Fr) are now widely used due to improved specific properties compared to more conventional materials. In particular the automotive and aerospace industries are turning towards these materials for weight reduction. Moreover the anti corrosion properties of FRP are also of interest to manufacturers as an alternative to metallic materials. The reinforcing fibres used in the composite materials can be assembled using a variety of textile processing techniques. Of these, 2-D braiding is particularly attractive for hollow components or sandwich laminates. In this study flat plaques were produced by braiding commingled yam at various angles on a cylindrical mandrel, after which the braids were slit and consolidated by non-isothermal compression moulding. Mechanical properties of the composites were measured and the results are discussed with reference to the arising fibre architecture and microstructure. The results obtained illustrate that there is a major influence of the fibre orientation on the final properties of the composite. (author)
Ariza, E.; Rocha, L. A.
2005-01-01
Practical applications of metal/ceramic joints can be found in the biomedical field regarding the encapsulation of implantable telemetric devices, the fabrication of crowns and bridges for dental restoration, or in the production of drug delivery systems, biomedical sensors and electrodes. Most of metal/ceramic joints are produced by the active metal brazing technique, which originates a multi-layered interface which should be able of accommodating the abrupt electronic, crystallographic, ...
Braided Field Quantization from Quantum Poincare Covariance
Lukierski, Jerzy
2012-01-01
We demonstrate that the covariance of the algebra of quantum NC fields under quantum-deformed Poincare symmetries implies the appearence of braided algebra of fields and the notion of braided locality in NC QFT. We briefly recall the historical development of NC QFT which was firstly formulated in the framework using classical relativistic symmetries but further it was described as generated by the quantum-deformed symmetries. We argue that consistent covariant quantum-deformed formalism requires "braiding all the way", in particular braided commutator of deformed field oscillators as well as the braid between the field oscillators and noncommutative Fourier exponentials. As example of braided quantum-deformed NC QFT we describe the NC scalar free fields on noncommutative canonical (Moyal-Weyl) space-time with braided c-number field commutator which implies braided locality.
Medical Image Retrieval Based on Multi-Layer Resampling Template
Institute of Scientific and Technical Information of China (English)
WANG Xin-rui; YANG Yun-feng
2014-01-01
Medical image application in clinical diagnosis and treatment is becoming more and more widely, How to use a large number of images in the image management system and it is a very important issue how to assist doctors to analyze and diagnose. This paper studies the medical image retrieval based on multi-layer resampling template under the thought of the wavelet decomposition, the image retrieval method consists of two retrieval process which is coarse and fine retrieval. Coarse retrieval process is the medical image retrieval process based on the image contour features. Fine retrieval process is the medical image retrieval process based on multi-layer resampling template, a multi-layer sampling operator is employed to extract image resampling images each layer, then these resampling images are retrieved step by step to finish the process from coarse to fine retrieval.
Multi-layer boron thin-film detectors for neutrons
International Nuclear Information System (INIS)
Intrinsic efficiencies of multi-layer boron-10 thin-film detectors were studied theoretically and experimentally. For multi-layer schemes based on an optimized single-layer film thickness, the practical efficiency is limited to about 42% for thermal neutrons. This is about half the efficiency of a moderated 3He detectors in commercial use for portal monitoring. The efficiency limitation is due to charged particle loss in the boron layers and substrates. The same loss mechanism will prevent all substrate-based boron detectors from ever reaching the intrinsic efficiencies of high-pressure 3He tubes, independent of substrate geometry and material composition. Experimental data also indicate that the multi-layer detector configuration can have an efficiency approaching the theoretical limit. Excellent n/γ discrimination has also been achieved using an ionization chamber.
Multi-layer surface profiling using gated wavefront sensing
Wang, Xin; Nordin, Nur Dalilla; Tik, Eddy Chow Mun; Tan, ChingSeong; Chew, Kuew Wai; Menoni, Carmen
2015-01-01
Recently, multi-layer surface profiling and inspection has been considered an emerging topic that can be used to solve various manufacturing inspection problems, such as graded index lenses, TSV (Thru-Silicon Via), and optical coating. In our study, we proposed a gated wavefront sensing approach to estimate the multi-layer surface profile. In this paper, we set up an experimental platform to validate our theoretical models and methods. Our test bed consists of pulse laser, collimator, prism, well-defined focusing lens, testing specimen, and gated wavefront sensing assembly (e.g., lenslet and gated camera). Typical wavefront measurement steps are carried out for the gated system, except the reflectance is timed against its time of flight as well as its intensity profile. By synchronizing the laser pulses to the camera gate time, it is possible to discriminate a multi-layer wavefront from its neighbouring discrete layer reflections.
Tensile properties of braided composite rods
Pereira, Cristiana Gonilho; Fangueiro, Raúl; Jalali, Said; Araújo, Mário Duarte de; Marques, P
2008-01-01
The current work is concerning the development of braided reinforced composite rods for civil engineering applications, namely for concrete internal reinforcement. The research study aims to understand the mechanical behaviour of braided reinforced composite rods produced from an innovative technique. Seven types of braided reinforced composite rods were produced, varying the type of fibres used as a core reinforcement of a polyester braided fabric. E-glass, carbon, HT polyethylene fibres ...
Mosaic Face Image Recognition on Multi-Layer Neural Network
Yamamori, Kuhihito; Nogawa, Reo; Yoshihara, Ikuo
2003-01-01
Face image recognition is an impotant technology for security,communication area,etc.. In this reserch,###we try to show the optimal parameters in multi-layer neural network for mosaic face image recognition.###By using of mosaic face images,the amount of image dara can be reduced,and it can also avoid###the affect of noise.Through our experiments,a multi-layer neural network showed 98.7% of recognition###on 8 x 8 mosaic images.
Braided Composite Technologies for Rotorcraft Structures
Jessie, Nathan
2015-01-01
A&P Technology has developed a braided material approach for fabricating lightweight, high-strength hybrid gears for aerospace drive systems. The conventional metallic web was replaced with a composite element made from A&P's quasi-isotropic braid. The 0deg, +/-60deg braid architecture was chosen so that inplane stiffness properties and strength would be nearly equal in all directions. The test results from the Phase I Small Spur Gear program demonstrated satisfactory endurance and strength while providing a 20 percent weight savings. (Greater weight savings is anticipated with structural optimization.) The hybrid gears were subjected to a proof-of-concept test of 1 billion cycles in a gearbox at 10,000 revolutions per minute and 490 in-lb torque with no detectable damage to the gears. After this test the maximum torque capability was also tested, and the static strength capability of the gears was 7x the maximum operating condition. Additional proof-of-concept tests are in progress using a higher oil temperature, and a loss-of-oil test is planned. The success of Phase I led to a Phase II program to develop, fabricate, and optimize full-scale gears, specifically Bull Gears. The design of these Bull Gears will be refined using topology optimization, and the full-scale Bull Gears will be tested in a full-scale gear rig. The testing will quantify benefits of weight savings, as well as noise and vibration reduction. The expectation is that vibration and noise will be reduced through the introduction of composite material in the vibration transmission path between the contacting gear teeth and the shaft-and-bearing system.
Problematic of fracture toughness estimation of multi-layer pipes
Czech Academy of Sciences Publication Activity Database
Nezbedová, E.; Vlach, B.; Knésl, Zdeněk; Šestáková, Lucie
Budapest : Plastics Pipe Institute, 2008, s. 1-9. [ Plastics Pipes XIV. Budapest (HU), 22.09.2008-24.09.2008] R&D Projects: GA ČR GA106/07/1284 Institutional research plan: CEZ:AV0Z20410507 Keywords : life-time * multi-layer pipes * fracture toughness Subject RIV: JL - Materials Fatigue, Friction Mechanics
Multi-layer thermoplastic composites manufacturing processes: simulations and experiments
Thije, ten René; Haanappel, Sebastiaan
2011-01-01
Press forming of multi-layer thermoplastic composite laminates is a fast and cost-effective method to produce thin shelled products. This paper shows that virtual forming provides designers with a tool to determine and to optimize the formability of these composite products. Forming simulations iden
Simple braids for surface homeomorphisms
Parwani, Kamlesh
2005-01-01
Let S be a compact, oriented surface with negative Euler characteristic and let f be a homeomorphism of S that is isotopic to the identity. If there exists a periodic orbit with a non-zero rotation vector, then there exists a simple braid with the same rotation vector.
Permutation Analysis of Track and Column Braiding
Institute of Scientific and Technical Information of China (English)
李毓陵; 丁辛; 胡良剑
2004-01-01
The positions of braiding carrier in track and column braiding are represented by a diagrammatic braiding plan and a corresponding lattice-array is defined. A set is then formed so that the permutation analysis can be performed to represent the movement of carriers in a braiding process. The process of 4-step braiding is analyzed as an example to describe the application of the proposed method by expressing a braiding cycle as a product of disjoint cycles. As a result, a mapping relation between the disjoint cycles and the movement of carriers is deduced. Following the same analysis principles, a process of 8-step braiding and the corresponding initial state of the lattice-array is developed. A successful permutation analysis to the process manifests the general suitability of the proposed method.
Mechanical Properties of Triaxial Braided Carbon/Epoxy Composites
Bowman, C. L.; Roberts, G. D.; Braley, M. S.; Xie, M.; Booker, M. J.
2003-01-01
In an on-going effort to increase the safety and efficiency of turbine engines, the National Aeronautics and Space Administration is exploring lightweight alternatives to the metal containment structures that currently encase commercial jet engines. Epoxy reinforced with braided carbon fibers is a candidate structural material which may be suitable for an engine case. This paper reports flat-coupon mechanical-property experiments performed to compliment previously reported subcomponent impact testing and analytical simulation of containment structures. Triaxial-braid T700/5208 epoxy and triaxial-braid T700h436 toughened epoxy composites were evaluated. Also, two triaxial-braid architectures (0 degrees plus or minus 60 degrees, and 0 degrees plus or minus 45 degrees) with the M36 resin were evaluated through tension, compression, and shear testing. Tensile behavior was compared between standard straight-sided specimens (ASTM D3039) and bow-tie specimens. Both double-notch shear (ASTM D3846) and Iosepescu (ASTM D5379) tests were performed as well. The M36/O degrees plus or minus 45 degrees configuration yield the best response when measurements were made parallel to the axial tows. Conversely, the M36/0 degrees plus or minus 60 degrees configuration was best when measurements were made perpendicular to the axial tows. The results were used to identify critical properties and to augment the analysis of impact experiments.
The Picard crossed module of a braided tensor category
Davydov, Alexei; Nikshych, Dmitri
2012-01-01
For a finite braided tensor category we introduce its Picard crossed module consisting of the group of invertible module categories and the group of braided tensor autoequivalences. We describe the Picard crossed module in terms of braided autoequivalences of the Drinfeld center of the braided tensor category. As an illustration, we compute the Picard crossed module of a braided pointed fusion category.
Spectroscopic characterization of ion-irradiated multi-layer graphenes
Energy Technology Data Exchange (ETDEWEB)
Tsukagoshi, Akira [Graduate School of Engineering, University of Hyogo, Himeji, Hyogo 671-2280 (Japan); RIKEN SPring-8 Center, Sayo, Hyogo 679-5148 (Japan); Honda, Shin-ichi, E-mail: s-honda@eng.u-hyogo.ac.jp [Graduate School of Engineering, University of Hyogo, Himeji, Hyogo 671-2280 (Japan); RIKEN SPring-8 Center, Sayo, Hyogo 679-5148 (Japan); Osugi, Ryo [Graduate School of Engineering, University of Hyogo, Himeji, Hyogo 671-2280 (Japan); RIKEN SPring-8 Center, Sayo, Hyogo 679-5148 (Japan); Okada, Hiraku [Graduate School of Engineering, University of Hyogo, Himeji, Hyogo 671-2280 (Japan); Niibe, Masahito [Laboratory of Advanced Science and Technology for Industry, University of Hyogo, Kamigori, Hyogo 678-1205 (Japan); Terasawa, Mititaka [Laboratory of Advanced Science and Technology for Industry, University of Hyogo, Kamigori, Hyogo 678-1205 (Japan); RIKEN SPring-8 Center, Sayo, Hyogo 679-5148 (Japan); Hirase, Ryuji; Izumi, Hirokazu; Yoshioka, Hideki [Hyogo Prefectural Institute of Technology, Kobe 654-0037 (Japan); Niwase, Keisuke [Hyogo University of Teacher Education, Kato, Hyogo 673-1494 (Japan); Taguchi, Eiji [Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, Ibaraki, Osaka 567-0047 (Japan); Lee, Kuei-Yi [Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan (China); Oura, Masaki [RIKEN SPring-8 Center, Sayo, Hyogo 679-5148 (Japan)
2013-11-15
Low-energy Ar ions (0.5–2 keV) were irradiated to multi-layer graphenes and the damage process, the local electronic states, and the degree of alignment of the basal plane, and the oxidation process upon ion irradiation were investigated by Raman spectroscopy, soft X-ray absorption spectroscopy (XAS) and in situ X-ray photoelectron spectroscopy (XPS). By Raman spectroscopy, we observed two stages similar to the case of irradiated graphite, which should relate to the accumulations of vacancies and turbulence of the basal plane, respectively. XAS analysis indicated that the number of sp{sup 2}-hybridized carbon (sp{sup 2}-C) atoms decreased after ion irradiation. Angle-resolved XAS revealed that the orientation parameter (OP) decreased with increasing ion energy and fluence, reflecting the turbulence of the basal plane under irradiation. In situ XPS shows the oxidation of the irradiated multi-layer graphenes after air exposure.
A multi-layer flood safety approach towards resilient cities
Leskens, Johannes; Boomgaard, Marcel; Zuijlen, van, M.C.A.; Hollanders, Peter; Butler, D.; Djordjevic, S; Hammond, M.J.
2013-01-01
The multi-layer safety approach focuses on flood risk reduction through three types of measures: (1) prevention through dikes, levees and dams , (2) a flood resilient spatial planning and (3) an adequate crisis management. Whereas the official Dutch policy propagates the multi-level safety approach, the current Dutch water safety policy is still focused on prevention only (layer 1). The integration with the two other layers (i.e. a flood resilient spatial planning and an adequate disaster man...
Guided waves in a multi-layered optical structure
Torres, Pedro J.
2006-09-01
Motivated by the study of the propagation of electromagnetic waves through a multi-layered optical medium, we prove the existence of two different kinds of homoclinic solutions to the origin in a Schrödinger equation with a nonlinear term. We use a Krasnoselskii fixed point theorem together with a compactness criterion due to Zima. The main results are illustrated with concrete examples of practical interest such as self-focusing nonlinearities of Kerr and non-Kerr type.
Multi-layer model predictive control of complex water systems
Sun, Congcong
2015-01-01
This thesis is devoted to design a multi-layer MPC controller applied to the complex water network taking into account that the different layers with different time scales and control objectives have their own controller. A two-layer temporal hierarchy coordinating scheme has been applied to coordinate the MPC controllers for the supply and transportation layers. An integrated real-time simulation-optimization approach which contributes to consider the effect of more complex dynamics, better ...
Acoustic performance analysis of bionic coupling multi-layer structure
Wang, Y. H.; Zhang, C. C.; Ren, L.Q.; Ichchou, Mohamed; Galland, Marie-Annick; Bareille, Olivier
2014-01-01
The interest of this paper lies in the proposition of using bionic method to develop a new sound absorption structure. Inspired by the coupling absorption structure of the skin and feather of a typical silent flying bird - owl, a bionic coupling multi-layer structure model is developed, which is composed of a micro-silt plate, porous fibrous material and a flexible micro-perforated membrane backed with airspace. The impedance transfer method is applied to calculate the absorption coefficients...
Efficient analytical solutions for heated, pressurized multi-layered cylinders
2013-01-01
Two independent sets of analytical solutions, one based on matrix inversion and one based on iteration, are derived for the displacement field and corresponding stress state in multi-layer cylinders subjected to pressure and thermal loading. Solutions are developed for cylinders that are axially free with no friction between layers (plane stress), for cylinders that are fully restrained axially (plane strain) and for axially loaded and spring-mounted cylinders, assuming that the combined two-...
Non-destructive Inspection of Multi-layered Composite Using Ultrasonic Signal Processing
Energy Technology Data Exchange (ETDEWEB)
Ng, S C; Ismail, N; Ali, Aidy; Sahari, Barkawi [Intelligent System and Robotic Laboratory, Institute of Advanced Technology, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Yusof, J M; Chu, B W, E-mail: ngsokchoo@gmail.com [Department of Mechanical and Manufacturing Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia)
2011-02-15
Composites exhibit higher strength and stiffness, better design practice and greater corrosion resistance compare to metal material. However, composites are susceptible to impact damage and the typical damage behaviour in the laminated composites is fibre-breakage and delamination. Detection of failure in laminated composites is complicated compared with ordinary non-destructive testing for metal materials as they are sensitive to echoes drown in noise due to the properties of the constituent materials and the multi-layered structure of the composites. In the current study, the detection of failure in multi-layered composite materials is investigated. To obtain a high probability of defect detection in composite materials, signal processing algorithms were used to resolve echoes associated with defects in glass fibre-reinforced plastics (GRP) detected by using ultrasonic testing. Pulse-echo method with single transducer was used to transmit and receive ultrasound. The obtained signals were processed to reduce noise and to extract suitable features. Results were validated on GRP with and without defects in order to demonstrate the feasibility of the method on defect detection in composites.
Braided nodal lines in wave superpositions
Dennis, M R
2003-01-01
Nodal lines (phase singularities, optical vortices) are the generic interference fringes of complex scalar waves. Here, an exact complex solution of the time independent wave equation (Helmholtz equation) is considered, possessing nodal lines which are braided in the form of a borromean, or pig-tail braid. The braid field is a superposition of counterpropagating, counterrotating, non-coaxial order 3 Bessel beams, and a plane wave whose propagation is perpendicular to that of the beams. The construction is structurally stable, and can be generalized to a limited class of other braids.
Nanosecond and sub-nanosecond pulsed laser ablation of thin single and multi-layer packaging films
International Nuclear Information System (INIS)
Translating single and multi-layer packaging films are exposed to 0.5–0.8 ns laser pulses of wavelength 1064 nm and 10–12.5 ns laser pulses of wavelength 515 nm. Ablation depths and threshold fluences are reported for single-layer polyethylene (PE), polypropylene (PP) and aluminium of thickness 20–50 μm. Interaction and cut widths are reported for the same single-layer films and for four multi-layer films comprising aluminium-polypropylene and aluminium-paper. Ablation of the PE and PP films is only possible in the tested parameter range with 0.5 ns, 1064 nm pulses. Though a one order of magnitude reduction in the ablation threshold of aluminium is observed with 0.5–0.8 ns, 1064 nm pulses, the efficiency of material removal for fluences >8 J cm−2 is superior with 10–12.5 ns, 515 nm pulses. Multi-layer film response is found to be heavily dictated by the thickness of metallic layers. For multi-layer films with aluminium layers of thickness 7–9 μm, adjacent layers are removed by inter-layer heat conduction from the aluminium layer, in some cases leading to very large cut widths. For multi-layer films with aluminium layers of thickness <0.1 μm, direct ablation of all layers must take place for complete film penetration. The study provides quantitative results regarding process efficiency and quality for application of pulsed laser sources within the packaging industry.
Ding, J.; Colegrove, Paul A.; Mehnen, Jorn; Ganguly, Supriyo; Sequeira Almeida, P. M.; Wang, F.; Williams, Stewart W.
2011-01-01
Wire and Arc Additive Layer Manufacturing (WAALM) is gaining increasing popularity as the process allows the production of large custom-made metal workpieces with high deposition rates. The high power input of the welding process, causes significant residual stress and distortion of the workpiece. This paper describes the thermo-mechanical behaviour of the multi-layer wall structure made by the WAALM process. A 3D thermo-elastic–plastic transient model and a model based on a...
Microfabrication of multi-layered electrodes for dielectrophoresis-based field flow fractionation
Mathew, Bobby; Alazzam, Anas; Khashan, Saud A.
2015-06-01
This article details the process layout required for realizing a three-dimensional arrangement of electrodes in a microfluidic device for field flow fractionation based on dielectrophoresis. The metal electrodes are placed horizontally, in a stair-case arrangement, and pass through the bulk of the fluid. Several standard microfabrication processes are employed, in realizing this microdevice, including multi-layer photolithography, casting and plasma bonding. Thus the process layout is repeatable and reproducible. The feasibility of this process layout is demonstrated using three electrodes arranged in aforementioned manner; nevertheless, this process can be extended to as many electrodes as desired in the horizontal direction. This process layout can will make applications possible that were not possible till date due to the inability in microfabricating three-dimensional horizontal metal electrodes that run through the entire width of the microchannel.
APT analyses of deuterium-loaded Fe/V multi-layered films
Gemma, R.
2009-04-01
Interaction of hydrogen with metallic multi-layered thin films remains as a hot topic in recent days Detailed knowledge on such chemically modulated systems is required if they are desired for application in hydrogen energy system as storage media. In this study, the deuterium concentration profile of Fe/V multi-layer was investigated by atom probe tomography (APT) at 60 and 30 K. It is firstly shown that deuterium-loaded sample can easily react with oxygen at the Pd capping layer on Fe/V and therefore, it is highly desired to avoid any oxygen exposure after D(2) loading before APT analysis. The analysis temperature also has an impact on D concentration profile. The result taken at 60 K shows clear traces of surface segregation of D atoms towards analysis surface. The observed diffusion profile of D allows us to estimate an apparent diffusion coefficient D. The calculated D at 60 K is in the order of 10(-17) cm(2)/s, deviating 6 orders of magnitude from an extrapolated value. This was interpreted with alloying, D-trapping at defects and effects of the large extension to which the extrapolation was done. A D concentration profile taken at 30 K shows nosegregation anymore and a homogeneous distribution at C(D) = 0.05(2) D/Me, which is in good accordance with that measured in the corresponding pressure-composition isotherm. (C) 2008 Elsevier B.V. All rights reserved.
Majorana Braiding with Thermal Noise
Pedrocchi, Fabio L.; DiVincenzo, David P.
2015-09-01
We investigate the self-correcting properties of a network of Majorana wires, in the form of a trijunction, in contact with a parity-preserving thermal environment. As opposed to the case where Majorana bound states are immobile, braiding Majorana bound states within a trijunction introduces dangerous error processes that we identify. Such errors prevent the lifetime of the memory from increasing with the size of the system. We confirm our predictions with Monte Carlo simulations. Our findings put a restriction on the degree of self-correction of this specific quantum computing architecture.
Research on Multi-Layer Distributed HF Radio Network Structure
Institute of Scientific and Technical Information of China (English)
Hui Dai; Chun-Jiang Wang; Quan Yu
2008-01-01
High frequency (HF) transmission is an important communication techniques. However, conventional point-to-point transmission can be easily destroyed, which limits its utilization in practice. HF networking communication has the capability against demolishment. The network structure is one of the key factors for HF networking communication. In this paper, a novel analysis method of the network connectedness based on the eigenvalue is derived, and a multi-layer distributed HF radio network structure is proposed. Both the theore tical analysis and the computer simulation results verify that the application of the proposed network structure in the HF radio communication can improve the anti demolishment ability of the HF network efficiently.
Self-organized percolation in multi-layered structures
International Nuclear Information System (INIS)
We present a self-organized model for the growth of two- and three-dimensional percolation clusters in multi-layered structures. Anisotropy in the medium is modeled by randomly allocating layers of different physical properties. A controlling mechanism for the growing aggregate perimeter is introduced in such a manner that the system self-tunes to a stationary regime that corresponds to the percolation threshold. The critical probability for infinite growth is studied as a function of the anisotropy of the medium
Emergent Braided Matter of Quantum Geometry
Directory of Open Access Journals (Sweden)
Sundance Bilson-Thompson
2012-03-01
Full Text Available We review and present a few new results of the program of emergent matter as braid excitations of quantum geometry that is represented by braided ribbon networks. These networks are a generalisation of the spin networks proposed by Penrose and those in models of background independent quantum gravity theories, such as Loop Quantum Gravity and Spin Foam models. This program has been developed in two parallel but complimentary schemes, namely the trivalent and tetravalent schemes. The former studies the braids on trivalent braided ribbon networks, while the latter investigates the braids on tetravalent braided ribbon networks. Both schemes have been fruitful. The trivalent scheme has been quite successful at establishing a correspondence between braids and Standard Model particles, whereas the tetravalent scheme has naturally substantiated a rich, dynamical theory of interactions and propagation of braids, which is ruled by topological conservation laws. Some recent advances in the program indicate that the two schemes may converge to yield a fundamental theory of matter in quantum spacetime.
Competitive dynamics of lexical innovations in multi-layer networks
Javarone, Marco Alberto
2013-01-01
We study the introduction of lexical innovations in a community of language users. Lexical innovations, i.e., new terms added in the people's vocabulary, have an important role in the process of language evolution. Nowadays, the information spreading takes place over different networks, as online/offline social networks, the World Wide Web and other information networks. The whole system, composed by networks of different nature, can be represented as a multi-layer network. In this context, the spreading of lexical innovations has a peculiar behavior. In particular, a lexical innovation can generate incomprehensions when used without providing its meaning and, in this case, more than one meaning can emerge in the population. Therefore, lexical innovations cannot be considered as simple informations. We develop a model to analyze this scenario by using a multi-layer network composed of a social network and a media network. This latter represents the set of all information systems of a society, e.g., television...
Numerical simulation of multi-layered textile composite reinforcement forming
International Nuclear Information System (INIS)
One important perspective in aeronautics is to produce large, thick or/and complex structural composite parts. The forming stage presents an important role during the whole manufacturing process, especially for LCM processes (Liquid Composites Moulding) or CFRTP (Continuous Fibre Reinforcements and Thermoplastic resin). Numerical simulations corresponding to multi-layered composite forming allow the prediction for a successful process to produce the thick parts, and importantly, the positions of the fibres after forming to be known. This paper details a set of simulation examples carried out by using a semi-discrete shell finite element made up of unit woven cells. The internal virtual work is applied on all woven cells of the element taking into account tensions, in-plane shear and bending effects. As one key problem, the contact behaviours of tool/ply and ply/ply are described in the numerical model. The simulation results not only improve our understanding of the multi-layered composite forming process but also point out the importance of the fibre orientation and inter-ply friction during formability.
Elastic Buckling Behaviour of General Multi-Layered Graphene Sheets
Directory of Open Access Journals (Sweden)
Rong Ming Lin
2015-04-01
Full Text Available Elastic buckling behaviour of multi-layered graphene sheets is rigorously investigated. Van der Waals forces are modelled, to a first order approximation, as linear physical springs which connect the nodes between the layers. Critical buckling loads and their associated modes are established and analyzed under different boundary conditions, aspect ratios and compressive loading ratios in the case of graphene sheets compressed in two perpendicular directions. Various practically possible loading configurations are examined and their effect on buckling characteristics is assessed. To model more accurately the buckling behaviour of multi-layered graphene sheets, a physically more representative and realistic mixed boundary support concept is proposed and applied. For the fundamental buckling mode under mixed boundary support, the layers with different boundary supports deform similarly but non-identically, leading to resultant van der Waals bonding forces between the layers which in turn affect critical buckling load. Results are compared with existing known solutions to illustrate the excellent numerical accuracy of the proposed modelling approach. The buckling characteristics of graphene sheets presented in this paper form a comprehensive and wholesome study which can be used as potential structural design guideline when graphene sheets are employed for nano-scale sensing and actuation applications such as nano-electro-mechanical systems.
Vulnerability of multi-layer networks under malware spreading
Vida, Rafael; Cuenda, Sara
2013-01-01
Computer viruses are evolving by developing spreading mechanisms based on the use of multiple vectors of propagation. The use of the social network as an extra vector of attack to penetrate the security measures in IP networks is improving the effectiveness of the malware, and have therefore been used by the most aggressive viruses, like Conficker and Stuxnet. In this work we use multi-layer networks to model the propagation of these kind of viruses. In particular, we study the propagation of a SIS model on a multi-layer network where the state of each node is layer-independent and the dynamics in each network follows either a contact process or a reactive process, with different propagation rates. We show that the interplay between the layers leads to a non-trivial dynamics, with an epidemic onset that may trigger before it triggers in each isolated network. We apply this study to the case of a real two-layer network: a Spanish scientific community of Statistical Physics, formed by a social network of scient...
Spectroscopic study of atomic beams generated by laser ablation of multi-layer targets
International Nuclear Information System (INIS)
An experiment is described where Li- and Al-beams were generated by ablation of thin, multi-layer targets using a Q-Switched ruby laser with a total energy density up to 30 Jcm-2. Measurements using laser induced fluorescence and mass spectroscopy were combined to analyse the energy- and density distribution and the temporal structure of the beams. The maximum energy turned out to be several eV for Li and several 10 eV for Al with a peak density in the range of 1010 cm-3 for both Li and Al. The targets were analysed by optical microscopy and secondary ion mass spectroscopy providing information about the size of the spots and the structure of the metal film before and after the ablation experiment. (orig.)
Systematically generated two-qubit anyon braids
Carnahan, Caitlin; Zeuch, Daniel; Bonesteel, N. E.
2016-05-01
Fibonacci anyons are non-Abelian particles for which braiding is universal for quantum computation. Reichardt has shown how to systematically generate nontrivial braids for three Fibonacci anyons which yield unitary operations with off-diagonal matrix elements that can be made arbitrarily small in a particular natural basis through a simple and efficient iterative procedure. This procedure does not require brute force search, the Solovay-Kitaev method, or any other numerical technique, but the phases of the resulting diagonal matrix elements cannot be directly controlled. We show that despite this lack of control the resulting braids can be used to systematically construct entangling gates for two qubits encoded by Fibonacci anyons.
Enhance Production Rate of Braiding Machine Using Speed Reduction Technique
Manoj A. Kumbhalkar; Sachin V. Mate; Sushama Dhote; Mudra Gondane
2013-01-01
Textile designing is a technical process which includes different methods for production of textile, surface design and structural design of a textile. Braid is the textile product having various types like round and flat braid made by using textile threads or wires which are alternatively interwoven in braiding machine. A small scale industry in Nagpur produces each type of cotton braids using 16 spindle braiding machines on the single line shaft acquired power from 0.50 HP motor runs at 144...
Detecting coherent structures using braids
Allshouse, Michael R
2011-01-01
The detection of coherent structures is an important problem in fluid dynamics, particularly in geophysical applications. For instance, knowledge of how regions of fluid are isolated from each other allows prediction of the ultimate fate of oil spills. Existing methods detect Lagrangian coherent structures, which are barriers to transport, by examining the stretching field as given by finite-time Lyapunov exponents. These methods are very effective when the velocity field is well-determined, but in many applications only a small number of flow trajectories are known, for example when dealing with oceanic float data. We introduce a topological method for detecting invariant regions based on a small set of trajectories. In the method we regard the two-dimensional trajectory data as a braid in three dimensions, with time being the third coordinate. Invariant regions then correspond to trajectories that travel together and do not entangle other trajectories. We detect these regions by examining the growth of hypo...
Optimization of multi-layer front-contact grid patterns for solar cells
Flat, A.; Milnes, A. G.
1979-01-01
In a front-contact grid pattern for a solar cell there is a trade-off necessary between shadowing loss and excessive power loss due to voltage drop in the metalization itself. If the metalization is too little there may be excessive contact resistance to the underlying semiconductor and insufficient coverage to control losses in the thin front-surface layer of the solar cell. Optimization of grid pattern area and geometry is considered analytically to minimize total losses. Worthwhile performance advantages are shown to be possible, particularly in concentrator systems, if multi-layer grid patterns are used. The current carrying fingers should be approximately square in metal cross section and the main current feedout bars should not only be wider but also thicker than the primary collecting fingers. This is termed multi-level metalization. Effective use of multi-level grid metalization allows much greater concentration-to-loss ratio for a cell of large area and permits good performance from cells of high front-layer sheet resistance.
Multi- Layer Tree Hierarchical Architecture Based on Web Service
Institute of Scientific and Technical Information of China (English)
TONG Hengjian; LI Deren; ZHU Xinyan; SHAO Zhenfeng
2006-01-01
To solve the problem of the information share and services integration in population information system, we propose a multi-layer tree hierarchical architecture. The com mand (Web Service Call) is recursively multicast from top layer of tree to bottom layer of tree and statistical data are gathered from bottom layer to top layer. We implemented the architecture by using Web Services technology. In our implementation, client program is the requestor of Web Services,and all leaf nodes of the last layer are only the provider of Web Services. For those nodes of intermediate layers, every node is not only the provider of Web Services, but also the dispatcher of Web Services. We take population census as an example to describe the working flow of the architecture.
Simulations of a multi-layer extended gating grid
Mulligan, J D
2016-01-01
A novel idea to control ion back-flow in time projection chambers is to use a multi-layer extended gating grid to capture back-flowing ions at the expense of live time and electron transparency. In this initial study, I perform simulations of a four-layer grid for the ALICE and STAR time projection chambers, using $\\text{Ne}-\\text{CO}_{2}\\;(90-10)$ and $\\text{Ar}-\\text{CH}_{4}\\;(90-10)$ gas mixtures, respectively. I report the live time and electron transparency for both 90% and 99% ion back-flow suppression. Additionally, for the ALICE configuration I study several effects: using a mesh vs. wire-plane grid, including a magnetic field, and varying the over-voltage distribution in the gating region. For 90% ion back-flow suppression, I achieve 75% live time with 86% electron transparency for ALICE, and 95% live time with 83% electron transparency for STAR.
Radio-transparent multi-layer insulation for radiowave receiver
Choi, J; Mima, S; Oguri, S; Takahashi, K; Tajima, O
2013-01-01
In the field of radiowave detection, enhancement of the amount of detected light is essential for greater scientific achievements. A large aperture system is a promising way to increase the number of photons that are received at the detectors. One challenge in the application of radio transmittable apertures is keeping the detectors cool. This is because transparency to thermal radiation above the radio frequency range increases the thermal load. For shielding from thermal radiation, the general strategy involves installation of thermal filters in the light path between the aperture and the detectors. However, enlargement of the aperture gives rise to a new difficulty: warming of the filter. A thermal radiation shielding technology that does not warm the associated filter while allowing enlargement of the aperture is long-awaited. We propose radio-transparent multi-layer insulation (RT-MLI), which comprises a set of stacked insulator layers that are transparent in the radiowave frequency range. The basic idea...
Investigation of multi-layer thin films for energy storage.
Energy Technology Data Exchange (ETDEWEB)
Renk, Timothy Jerome; Monson, Todd
2009-01-01
We investigate here the feasibility of increasing the energy density of thin-film capacitors by construction of a multi-layer capacitor device through ablation and redeposition of the capacitor materials using a high-power pulsed ion beam. The deposition experiments were conducted on the RHEPP-1 facility at Sandia National Laboratories. The dielectric capacitor filler material was a composition of Lead-Lanthanum-Zirconium-Titanium oxide (PLZT). The energy storage can be increased by using material of intrinsically high dielectric constant, and constructing many thin layers of this material. For successful device construction, there are a number of challenging requirements including correct stoichiometric and crystallographic composition of the deposited PLZT. This report details some success in satisfying these requirements, even though the attempt at device manufacture was unsuccessful. The conclusion that 900 C temperatures are necessary to reconstitute the deposited PLZT has implications for future manufacturing capability.
Numerical Analysis of Deflections of Multi-Layered Beams
Directory of Open Access Journals (Sweden)
Biliński Tadeusz
2015-03-01
Full Text Available The paper concerns the rheological bending problem of wooden beams reinforced with embedded composite bars. A theoretical model of the behaviour of a multi-layered beam is presented. The component materials of this beam are described with equations for the linear viscoelastic five-parameter rheological model. Two numerical analysis methods for the long-term response of wood structures are presented. The first method has been developed with SCILAB software. The second one has been developed with the finite element calculation software ABAQUS and user subroutine UMAT. Laboratory investigations were conducted on sample beams of natural dimensions in order to validate the proposed theoretical model and verify numerical simulations. Good agreement between experimental measurements and numerical results is observed.
A Multi-Layered Image Cache for Scientific Visualization
Energy Technology Data Exchange (ETDEWEB)
LaMar, E C
2003-06-26
We introduce a multi-layered image cache system that is designed to work with a pool of rendering engines to facilitate an interactive, frameless, asynchronous rendering environment. Our system decouples the rendering from the display of imagery. Therefore, it decouples render frequency and resolution from display frequency and resolution, and allows asynchronous transmission of imagery instead of the compute/send cycle of standard parallel systems. It also allows local, incremental refinement of imagery without requiring all imagery to be re-rendered. Images are placed in fixed position in camera (vs. world) space to eliminate occlusion artifacts. Display quality is improved by increasing the number of images. Interactivity is improved by decreasing the number of images.
Pareto distance for multi-layer network analysis
DEFF Research Database (Denmark)
Magnani, Matteo; Rossi, Luca
2013-01-01
on the nature of the connections required by the Pareto distance may in theory result in a large number of potential shortest paths between pairs of nodes. However, an experimental computation of distances on multi-layer networks of increasing size shows an interesting and non-trivial stable behavior.......Social Network Analysis has been historically applied to single networks, e.g., interaction networks between co-workers. However, the advent of on-line social network sites has emphasized the stratified structure of our social experience. Individuals usually spread their identities over multiple...... services, e.g., Facebook, Twitter, LinkedIn and Foursquare. As a result, the analysis of on-line social networks requires a wider scope and, more technically speaking, models for the representation of this fragmented scenario. The recent introduction of more realistic layered models has however determined...
Handwritten Arabic Numeral Recognition using a Multi Layer Perceptron
Das, Nibaran; Saha, Sudip; Haque, Syed Sahidul
2010-01-01
Handwritten numeral recognition is in general a benchmark problem of Pattern Recognition and Artificial Intelligence. Compared to the problem of printed numeral recognition, the problem of handwritten numeral recognition is compounded due to variations in shapes and sizes of handwritten characters. Considering all these, the problem of handwritten numeral recognition is addressed under the present work in respect to handwritten Arabic numerals. Arabic is spoken throughout the Arab World and the fifth most popular language in the world slightly before Portuguese and Bengali. For the present work, we have developed a feature set of 88 features is designed to represent samples of handwritten Arabic numerals for this work. It includes 72 shadow and 16 octant features. A Multi Layer Perceptron (MLP) based classifier is used here for recognition handwritten Arabic digits represented with the said feature set. On experimentation with a database of 3000 samples, the technique yields an average recognition rate of 94....
Polymer Nanocomposite Based Multi-layer Neutron Shields
International Nuclear Information System (INIS)
It is important to shield radiations generated from the various radiation sources including nuclear reactors, transportation and storage systems for the radioactive wastes, accelerator, hospital, and defense systems etc. In this regard, development of efficient, light and durable radiation shielding materials has been an issue for many years. High energy neutrons (fast neutrons) can be thermalized by colliding with the light elements such as hydrogen, and thermalized neutrons can be efficiently captured by neutron absorbers such as boron, lithium, or gadolinium, etc. To shield neutrons, it is common to use hydrogen rich polymer based shields containing thermal neutron absorbers. It is also necessary to shield secondary gamma radiations produced from nuclear reaction of neutrons with various materials. Hence, high density elements such as Fe, Pb, or W might be dispersed in the polymer base as well as with neutron absorbers at the same time. However, the particle sizes of these elements are in the range of several tens and hundreds micrometers causing possible leakage of radiation. To enhance radiation shielding efficiency, it is useful to use ultrafine particles to increase collision probability of radiation with the particles. Furthermore, it is theoretically possible to enhance radiation shielding efficiency by using the multi-layer structured shields whose constituents are different for each layer depending upon the shielding purpose under the same overall density. Also, material properties of the nanocomposites can be enhanced compared to the normal composites. This investigation is focused on characterization of the nanocomposite based multi-layer structured radiation shields compared to the conventional radiation shields
Experimental analysis on stress wave in inhomogeneous multi-layered structures
International Nuclear Information System (INIS)
The guided wave propagation in inhomogeneous multi-layered structures is experimentally explored based on theoretical dispersion curves. It turns out that proper selection of incident angle and frequency is critical for guided wave generation in multi-layered structures. Theoretical dispersion curves greatly depend on adhesive zone thickness, layer thickness and material properties. It was possible to determine the adhesive zone thickness of an inhomogeneous multi-layered structure by monitoring experimentally the change of dispersion curves.
Implementing Semantic Deduction of Propositional Knowledge in an Extension Multi-layer Perceptron
Institute of Scientific and Technical Information of China (English)
HUANGTian-min; PEIZheng
2003-01-01
The paper presents an extension multi-layer perceptron model that is capable of representing and reasoning propositional knowledge base. An extended version of propositional calculus is developed,and its some properties is discussed. Formulas of the extended calculus can be expressed in the extension multi-layer perceptron. Naturally, semantic deduction of propositional knowledge base can be imple-ment by the extension multi-layer perceptron, and by learning, an unknown formula set can be found.
Fatigue crack growth monitoring in multi-layered structures using guided ultrasonic waves
Kostson, E.; Fromme, P.
2009-01-01
This contribution investigates the application of low frequency guided ultrasonic waves for monitoring fatigue crack growth at fastener holes in the 2nd layer of multi-layered plate structures, a common problem in aerospace industry. The model multi-layered structure investigated consists of two aluminum plate-strips adhesively bonded using a structural paste adhesive. Guided ultrasonic waves were excited using multiple piezoelectric discs bonded to the surface of the multi-layered structure....
Comparative Proteome Analysis of Multi-Layer Cocoon of the Silkworm, Bombyx mori
Zhang, Yan; ZHAO, PING; Dong, Zhaoming; Wang, Dandan; Guo, Pengchao; Guo, Xiaomeng; Song, Qianru; Zhang, Weiwei; Xia, Qingyou
2015-01-01
Bombyx mori cocoon has a multi-layer structure that provides optimal protection for silkworm pupa. Research on the mechanical properties of the multi-layer structure revealed structure-property relationships of the cocoon. Here, we investigated the protein components of the B. mori cocoon in terms of its multi-layer structure. Liquid chromatography-tandem mass spectrometry identified 286 proteins from the multiple cocoon layers. In addition to fibroins and sericins, we identified abundant pro...
Symmetric centres of braided monoidal categories
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
This paper introduces the concept of‘symmetric centres' of braided monoidal categories. Let H be a Hopf algebra with bijective antipode over a field k. We address the symmetric centre of the Yetter-Drinfel'd module category HH(yD) and show that a left Yetter-Drinfel'd module M belongs to the symmetric centre of HH(yD) if and only if M is trivial. We also study the symmetric centres of categories of representations of quasitriangular Hopf algebras and give a sufficient and necessary condition for the braid of H(M) to induce the braid of (H(H)(A),(○)A,A,φ,l,r), or equivalently, the braid of (A#H(H),(○)A,A,φ,l,r), where A is a quantum commutative H-module algebra.
Infinitesimal 2-braidings and differential crossed modules
Cirio, Lucio S
2013-01-01
We categorify the notion of an infinitesimal braiding in a linear strict symmetric monoidal category, leading to the notion of a (strict) infinitesimal 2-braiding in a linear symmetric strict monoidal 2-category. We describe the associated categorification of the 4-term relation, leading to six categorified relations. We prove that any infinitesimal 2-braiding gives rise to a flat and fake flat 2-connection in the configuration space of $n$ undistinguishable particles in the complex plane, hence to a categorification of the Knizhnik-Zamolodchikov connection. We discuss infinitesimal 2-braidings in a category naturally assigned to every differential crossed module, leading to the notion of a quasi-invariant tensor in a differential crossed module. Finally we prove that quasi-invariant tensors exist in the differential crossed module associated to the string Lie-2-algebra.
Modelling planform changes of braided rivers
Jagers, Hendrik Reinhard Albert
2003-01-01
This study has focused on modelling techniques to predict planform changes of braided rivers and their relation with state-of-the-art knowledge on the physical processes and the availability of model input data
Braided magnetic fields: equilibria, relaxation and heating
Pontin, D I; Russell, A J B; Hornig, G
2015-01-01
We examine the dynamics of magnetic flux tubes containing non-trivial field line braiding (or linkage), using mathematical and computational modelling. The key results obtained from recent modelling efforts are summarised, in the context of testable predictions for the laboratory. We discuss the existence of braided force-free equilibria, and demonstrate that for a field anchored at perfectly-conducting plates, these equilibria exist and contain current sheets whose thickness scales inversely with the braid complexity - as measured for example by the topological entropy. By contrast, for a periodic domain braided exact equilibria typically do not exist, while approximate equilibria contain thin current sheets. In the presence of resistivity, reconnection is triggered at the current sheets and a turbulent relaxation ensues. We discuss the properties of this relaxation, and in particular the existence of constraints that may mean that the final state is not the linear force-free field predicted by Taylor's hypo...
Braided magnetic fields: equilibria, relaxation and heating
Pontin, D. I.; Candelaresi, S.; Russell, A. J. B.; Hornig, G.
2016-05-01
We examine the dynamics of magnetic flux tubes containing non-trivial field line braiding (or linkage), using mathematical and computational modelling, in the context of testable predictions for the laboratory and their significance for solar coronal heating. We investigate the existence of braided force-free equilibria, and demonstrate that for a field anchored at perfectly-conducting plates, these equilibria exist and contain current sheets whose thickness scales inversely with the braid complexity—as measured for example by the topological entropy. By contrast, for a periodic domain braided exact equilibria typically do not exist, while approximate equilibria contain thin current sheets. In the presence of resistivity, reconnection is triggered at the current sheets and a turbulent relaxation ensues. We finish by discussing the properties of the turbulent relaxation and the existence of constraints that may mean that the final state is not the linear force-free field predicted by Taylor’s hypothesis.
Diagrammatics of braided group gauge theory
Majid, S
1996-01-01
We develop a gauge theory or theory of bundles and connections on them at the level of braids and tangles. Extending recent algebraic work, we provide now a fully diagrammatic treatment of principal bundles, a theory of global gauge transformations, associated braided fiber bundles and covariant derivatives on them. We describe the local structure for a concrete Z_3-graded or `anyonic' realization of the theory.
Self-diagnosing braided composite rod
Fangueiro, Raúl; Zdraveva, E.; Pereira, Cristiana Gonilho; Ferreira, A.; Lanceros-Méndez, S.
2010-01-01
This paper presents the development of a braided reinforced composite rod (BCR) able to both reinforce and monitor the stress state of concrete structures. Carbon fibers have been used as sensing and reinforcing materials along with glass fiber. Various composites rods have been produced using an author patented technique based on a modified conventional braiding machine. The materials investigated were prepared with different carbon fiber content as follows: BCR2 (77% glass/23...
Concrete reinforced by braided fibre composite rods
Fangueiro, Raúl; Sousa, Guilherme José Miranda de; Soutinho, Hélder Filipe Cunha; Jalali, Said; Araújo, Mário Duarte de
2005-01-01
One of the most serious problems affecting concrete is corrosion of the steel reinforcement. Corrosion may occur due to reaction of lime present in hydrated cement with carbon dioxide or to the action of chlorides. The braiding technique is probably the most ancient production process for textile structures. Normally used for ropes and cables, braided fabrics are also very interesting for composite reinforcements due to their characteristics: in-plane multiaxial ...
On braided Poisson and quantum inhomogeneous groups
Zakrzewski, S.
1997-01-01
The well known incompatibility between inhomogeneous quantum groups and the standard q-deformation is shown to disappear (at least in certain cases) when admitting the quantum group to be braided. Braided quantum ISO(p,N-p) containing SO_q(p,N-p) with |q|=1 are constructed for N=2p, 2p+1, 2p+2. Their Poisson analogues (obtained first) are presented as an introduction to the quantum case.
Fan deltas and braid deltas: conceptual problems
Energy Technology Data Exchange (ETDEWEB)
McPherson, J.G.; Shanmugam, G.; Moiola, R.J.
1986-05-01
The concept of fan deltas has been widely misinterpreted in the geologic literature. A true fan delta is defined as an alluvial fan deposited into a standing body of water. Such sequences are of limited areal extent and are, as expected, uncommon in the rock record. By contrast, braid deltas (herein defined), formed by progradation of a braided fluvial system into a standing body of water, are a common geomorphic feature in many modern settings, and their deposits are common in the geologic record. Braid-delta sequences are often identified as fan deltas, on the false premise that coarse-grained deposits in a deltaic setting are always part of an alluvial fan complex. The authors find that most published examples of so called fan deltas contain no direct evidence for the presence of an alluvial fan. Even in examples where an alluvial fan could be documented, the authors found that, in many cases, the alluvial fan complex was far removed from the shoreline, separated by an extensive braid plain. The authors suggest that such systems are better classified as braid deltas. They consider that it is essential to distinguish the environmental setting of true fan deltas from that of braid deltas. Misclassification will lead to incorrect interpretations of expected facies, sandstone geometry, reservoir quality, and tectonic settings. Criteria based on geometry, vertical and lateral lithofacies associations, and paleocurrent patterns should be used to correctly identify and distinguish these depositional systems.
In Vitro Degradation of Polyglycolide/Chitosan Hybrid Braids
Institute of Scientific and Technical Information of China (English)
YUAN Xiaoyan; ZHANG Qingwei; WANG Yonglin; YAO Kangde
2005-01-01
Hybrid braids of polyglycolide (PGA) and chitosan were prepared by the three-yarn braiding method from PGA and chitosan fiber bundles. These braids were in vitro degraded by incubating them in phosphate buffered saline (PBS) at pH 7.4 and 37 ℃ for 5 weeks. Results suggested that PGA/chitosan hybrid braids degraded significantly. Scanning electron micrographs showed that chitosan fibers in the PGA/chitosan hybrid braid with about 750% PGA in weight (PGA75/chitosan) were shaped into gel-like after 5 weeks, but those in the hybrid braid with about 250% PGA in weight (PGA25/chitosan) did not change. After 5 weeks, the ultimate tensile loads of PGA and PGA75/chitosan braids lost almost completely, but those of chitosan and PGA25/chitosan braids remained around 14 N. The PGA/chitosan hybrid braids with higher initial ultimate tensile load would have potential applications in tendon/ligament tissue reconstruction.
MUPLEX: a compact multi-layered polymer foil collector for micrometeoroids and orbital debris
Energy Technology Data Exchange (ETDEWEB)
Kearsley, A T; Graham, G A; Burchell, M J; Taylor, E A; Drolshagen, G; Chater, R J; McPhail, D
2004-10-04
Detailed studies of preserved hypervelocity impact residues on spacecraft multi-layer insulation foils have yielded important information about the flux of small particles from different sources in low-Earth orbit. We have extended our earlier research on impacts occurring in LEO to design and testing of a compact capture device. MULPEX (MUlti-Layer Polymer EXperiment) is simple, cheap to build, lightweight, of no power demand, easy to deploy, and optimized for the efficient collection of impact residue for analysis on return to Earth. The capture medium is a stack of very thin (8 micron and 40 micron) polyimide foils, supported on poly-tetrafluoroethylene sheet frames, surrounded by a protective aluminum casing. The uppermost foil has a very thin metallic coating for thermal protection and resistance to atomic oxygen and ultra-violet exposure. The casing provides a simple detachable interface for deployment on the spacecraft, facing into the desired direction for particle collection. On return to the laboratory, the stacked foils are separated for examination in a variable pressure scanning electron microscope, without need for surface coating. Analysis of impact residue is performed using energy dispersive X-ray spectrometers. Our laboratory experiments, utilizing buck-shot firings of analogues to micrometeoroids (35-38 micron olivine) and space debris (4 micron alumina and 1mm stainless steel) in a light gas gun, have shown that impact residue is abundant within the foil layers, and preserves a record of the impacting particle, whether of micrometer or millimeter dimensions. Penetrations of the top foil are easily recognized, and act as a proxy for dimensions of the penetrating particle. Impact may cause disruption and melting, but some residue retains sufficient crystallographic structure to show clear Raman lines, diagnostic of the original mineral.
Сomputer Simulation of Heating Processes in Multi-Layer Composite Structures
Directory of Open Access Journals (Sweden)
R. I. Yesman
2006-01-01
Full Text Available The paper contains solution of the problem concerning heating of multi-layer materials. Method of finite elements has been used to solve the problem.On the basis of numerical experiments plots of temperature fields have been constructed and optimum operating conditions of heating processes of multi-layer structures of materials having special properties have been determined.
Fabrication and Characterization of multi-layer ceramics for electrochemical flue gas purification
DEFF Research Database (Denmark)
Schmidt, Cristine Grings; Ippolito, Davide; Bentzen, Janet Jonna; Andersen, Kjeld Bøhm; Kaiser, Andreas; Kammer Hansen, Kent
2013-01-01
Multi-layered ceramics for electrochemical flue gas purification were fabricated by tape casting and lamination or by multi-layer tape casting. The sintered bodies were studied by scanning electron microscopy and electrochemical impedance spectroscopy. It was shown that the samples made by multi...
Geometrical deployment for braided stent.
Bouillot, Pierre; Brina, Olivier; Ouared, Rafik; Yilmaz, Hasan; Farhat, Mohamed; Erceg, Gorislav; Lovblad, Karl-Olof; Vargas, Maria Isabel; Kulcsar, Zsolt; Pereira, Vitor Mendes
2016-05-01
The prediction of flow diverter stent (FDS) implantation for the treatment of intracranial aneurysms (IAs) is being increasingly required for hemodynamic simulations and procedural planning. In this paper, a deployment model was developed based on geometrical properties of braided stents. The proposed mathematical description is first applied on idealized toroidal vessels demonstrating the stent shortening in curved vessels. It is subsequently generalized to patient specific vasculature predicting the position of the filaments along with the length and local porosity of the stent. In parallel, in-vitro and in-vivo FDS deployments were measured by contrast-enhanced cone beam CT (CBCT) in idealized and patient-specific geometries. These measurements showed a very good qualitative and quantitative agreement with the virtual deployments and provided experimental validations of the underlying geometrical assumptions. In particular, they highlighted the importance of the stent radius assessment in the accuracy of the deployment prediction. Thanks to its low computational cost, the proposed model is potentially implementable in clinical practice providing critical information for patient safety and treatment outcome assessment. PMID:26891065
Zhu, H. L.; Yao, C.; Li, Y.; Pan, H. L.
2016-05-01
Future space missions require efficient delivery of large payloads over great distances, necessitating the use of high-energy cryogenic propellant. Therefore, reliable compound multi-layer insulation on cryogenic tank is a crucial part of future space exploration. Compound multi-layer insulation is composed of double-aluminized radiation shielding and separated by a combination of netting and bumper strips, with a foam substrate. Considering conduction, convection, and radiation in heat transfer, the thermal field of multi-layer insulation is analysis by theoretical analysis with different thickness of foam substrate and MLI. Based on the formerly theoretical analysis, the heat flux and apparent thermal conductivity are discussed under the different thickness of foam substrate and MLI. Finally, the optimum design of multi-layer thermal insulation is present in consideration of the thickness and insulation performance of multi-layer insulation.
A multi-layer network approach to MEG connectivity analysis.
Brookes, Matthew J; Tewarie, Prejaas K; Hunt, Benjamin A E; Robson, Sian E; Gascoyne, Lauren E; Liddle, Elizabeth B; Liddle, Peter F; Morris, Peter G
2016-05-15
Recent years have shown the critical importance of inter-regional neural network connectivity in supporting healthy brain function. Such connectivity is measurable using neuroimaging techniques such as MEG, however the richness of the electrophysiological signal makes gaining a complete picture challenging. Specifically, connectivity can be calculated as statistical interdependencies between neural oscillations within a large range of different frequency bands. Further, connectivity can be computed between frequency bands. This pan-spectral network hierarchy likely helps to mediate simultaneous formation of multiple brain networks, which support ongoing task demand. However, to date it has been largely overlooked, with many electrophysiological functional connectivity studies treating individual frequency bands in isolation. Here, we combine oscillatory envelope based functional connectivity metrics with a multi-layer network framework in order to derive a more complete picture of connectivity within and between frequencies. We test this methodology using MEG data recorded during a visuomotor task, highlighting simultaneous and transient formation of motor networks in the beta band, visual networks in the gamma band and a beta to gamma interaction. Having tested our method, we use it to demonstrate differences in occipital alpha band connectivity in patients with schizophrenia compared to healthy controls. We further show that these connectivity differences are predictive of the severity of persistent symptoms of the disease, highlighting their clinical relevance. Our findings demonstrate the unique potential of MEG to characterise neural network formation and dissolution. Further, we add weight to the argument that dysconnectivity is a core feature of the neuropathology underlying schizophrenia. PMID:26908313
Addressing stress corrosion cracking on multi layer pipeline coating systems
Energy Technology Data Exchange (ETDEWEB)
Hardy, Scott B.; Marr, James E. [Tuboscope Pipeline Services, Houston, TX (United States); Willmot, Martyn [Jotun Group (Norway); Norman, David [David Norman Corrosion Control, Cornwall (United Kingdom); Khera, Ashish [Allied Engineering, Portland, ME (United States)
2005-07-01
Stress corrosion cracking (SCC) is now recognized by operators worldwide as a significant threat to the safe operation of their pipeline systems. Gas, oil, and refined products lines have all been susceptible to this form of environmentally assisted cracking. As a result, operators and regulators have been incorporating data related to the development and prevalence of SCC into their risk management systems in order that they may effectively address this time-dependant threat. The National Association of Corrosion Engineers (NACE) published the first structured methodology for stress corrosion cracking direct assessment (SCCDA) in 2004 (RP0204-2004). Operators are now beginning to apply the methods outlined in the standard to assess their systems. Research and industry experience have shown that various pipeline coating systems can be more or less effective in preventing the formation and growth of SCC. Newer pipeline coatings, such as multi layer epoxy/extruded polyolefin systems have been widely regarded as effective coating systems to address the threat posed by SCC when they are properly applied. New field studies performed on a pipeline coated with a three layer epoxy/polyethylene system have raised the possibility that operators utilizing these types of coatings may need to reassess how they manage the SCC threat. (author)
Geometrical nonlinear free vibration of multi-layered graphene sheets
Energy Technology Data Exchange (ETDEWEB)
Wang Jinbao [School of Naval Architecture and Civil Engineering, Zhejiang Ocean University, Zhoushan 316000 (China); He Xiaoqiao; Kitipornchai, S [Department of Building and Construction, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong); Zhang Hongwu, E-mail: bcxqhe@cityu.edu.hk [State Key Laboratory of Structural Analysis for Industrial Equipment, Department of Engineering Mechanics, Faculty of Vehicle Engineering and Mechanics, Dalian University of Technology, Dalian 116024 (China)
2011-04-06
A nonlinear continuum model is developed for the nonlinear vibration analysis of multi-layered graphene sheets (MLGSs), in which the nonlinear van der Waals (vdW) interaction between any two layers is formulated explicitly. The nonlinear equations of motion are studied by the harmonic-balance methods. Based on the present model, the nonlinear stiffened amplitude-frequency relations of double-layered graphene sheets (DLGSs) are investigated in the spectral neighbourhood of lower frequencies. The influence of the vdW interaction on the vibration properties of DLGSs is well illustrated by plotting the resulting modes' shapes, in which in-phase and anti-phase vibrations of DLGSs are studied. In particular, the large-amplitude vibration which associates with the anti-phase resonant frequencies, separating DLGS into single-layered GSs, is a promising application that needs to be explored further. In contrast, the vibration modes that are associated with the resonant frequencies are nonidentical and give various vibration patterns, which indicates that MLGSs are highly suited to being used as high-frequency resonators.
Geometrical nonlinear free vibration of multi-layered graphene sheets
International Nuclear Information System (INIS)
A nonlinear continuum model is developed for the nonlinear vibration analysis of multi-layered graphene sheets (MLGSs), in which the nonlinear van der Waals (vdW) interaction between any two layers is formulated explicitly. The nonlinear equations of motion are studied by the harmonic-balance methods. Based on the present model, the nonlinear stiffened amplitude-frequency relations of double-layered graphene sheets (DLGSs) are investigated in the spectral neighbourhood of lower frequencies. The influence of the vdW interaction on the vibration properties of DLGSs is well illustrated by plotting the resulting modes' shapes, in which in-phase and anti-phase vibrations of DLGSs are studied. In particular, the large-amplitude vibration which associates with the anti-phase resonant frequencies, separating DLGS into single-layered GSs, is a promising application that needs to be explored further. In contrast, the vibration modes that are associated with the resonant frequencies are nonidentical and give various vibration patterns, which indicates that MLGSs are highly suited to being used as high-frequency resonators.
CASCADE - a multi-layer Boron-10 neutron detection system
Köhli, M; Allmendinger, F; Perrevoort, A -K; Schröder, T; Martin, N; Schmidt, C J; Schmidt, U
2016-01-01
The globally increased demand for helium-3 along with the limited availability of this gas calls for the development of alternative technologies for the large ESS instrumentation pool. We report on the CASCADE Project - a novel detection system, which has been developed for the purposes of neutron spin echo spectroscopy. It features 2D spatially resolved detection of thermal neutrons at high rates. The CASCADE detector is composed of a stack of solid boron-10 coated Gas Electron Multiplier foils, which serve both as a neutron converter and as an amplifier for the primary ionization deposited in the standard Argon-CO2 counting gas environment. This multi-layer setup efficiently increases the detection efficiency and serves as a helium-3 alternative. It has furthermore been possible to extract the signal of the charge traversing the stack to identify the very thin conversion layer of about 1 micrometer. This allows the precise determination of the time-of-flight, necessary for the application in MIEZE spin echo...
Equilibrium theory for braided elastic filaments
van der Heijden, Gert
Motivated by supercoiling of DNA and other filamentous structures, we formulate a theory for equilibria of 2-braids, i.e., structures formed by two elastic rods winding around each other in continuous contact and subject to a local interstrand interaction. Unlike in previous work no assumption is made on the shape of the contact curve. Rather, this shape is found as part of the solution. The theory is developed in terms of a moving frame of directors attached to one of the strands with one of the directors pointing to the position of the other strand. The constant-distance constraint is automatically satisfied by the introduction of what we call braid strains. The price we pay is that the potential energy involves arclength derivatives of these strains, thus giving rise to a second-order variational problem. The Euler-Lagrange equations for this problem give balance equations for the overall braid force and moment referred to the moving frame as well as differential equations that can be interpreted as effective constitutive relations encoding the effect that the second strand has on the first as the braid deforms under the action of end loads. Simple analytical cases are discussed first and used as starting solutions in parameter continuation studies to compute classes of both open and closed (linked or knotted) braid solutions.
Braid My Hair - Randy Owen sings out for sick children
... Bar Home Current Issue Past Issues Braid My Hair - Randy Owen sings out for sick children Past ... debut performance of his latest song, "Braid My Hair," was the highlight during this year's Songwriter's Dinner ...
A Secure Key Agreement Protocol Using Braid Groups
Atul Chaturvedi; Shyam Sundar
2010-01-01
This paper presents an authenticated key agreement protocol based on a braid group. It is proved that the proposed protocol meets several security attributes under the assumption that the Root Problem (RP) in braid group is a hard problem.
Energy management and multi-layer control of networked microgrids
Zamora, Ramon
Networked microgrids is a group of neighboring microgrids that has ability to interchange power when required in order to increase reliability and resiliency. Networked microgrid can operate in different possible configurations including: islanded microgrid, a grid-connected microgrid without a tie-line converter, a grid-connected microgrid with a tie-line converter, and networked microgrids. These possible configurations and specific characteristics of renewable energy offer challenges in designing control and management algorithms for voltage, frequency and power in all possible operating scenarios. In this work, control algorithm is designed based on large-signal model that enables microgrid to operate in wide range of operating points. A combination between PI controller and feed-forward measured system responses will compensate for the changes in operating points. The control architecture developed in this work has multi-layers and the outer layer is slower than the inner layer in time response. The main responsibility of the designed controls are to regulate voltage magnitude and frequency, as well as output power of the DG(s). These local controls also integrate with a microgrid level energy management system or microgrid central controller (MGCC) for power and energy balance for. the entire microgrid in islanded, grid-connected, or networked microgid mode. The MGCC is responsible to coordinate the lower level controls to have reliable and resilient operation. In case of communication network failure, the decentralized energy management will operate locally and will activate droop control. Simulation results indicate the superiority of designed control algorithms compared to existing ones.
Improved SVR Model for Multi-Layer Buildup Factor Calculation
International Nuclear Information System (INIS)
The accuracy of point kernel method applied in gamma ray dose rate calculations in shielding design and radiation safety analysis is limited by the accuracy of buildup factors used in calculations. Although buildup factors for single-layer shields are well defined and understood, buildup factors for stratified shields represent a complex physical problem that is hard to express in mathematical terms. The traditional approach for expressing buildup factors of multi-layer shields is through semi-empirical formulas obtained by fitting the results of transport theory or Monte Carlo calculations. Such an approach requires an ad-hoc definition of the fitting function and often results with numerous and usually inadequately explained and defined correction factors added to the final empirical formula. Even more, finally obtained formulas are generally limited to a small number of predefined combinations of materials within relatively small range of gamma ray energies and shield thicknesses. Recently, a new approach has been suggested by the authors involving one of machine learning techniques called Support Vector Machines, i.e., Support Vector Regression (SVR). Preliminary investigations performed for double-layer shields revealed great potential of the method, but also pointed out some drawbacks of the developed model, mostly related to the selection of one of the parameters describing the problem (material atomic number), and the method in which the model was designed to evolve during the learning process. It is the aim of this paper to introduce a new parameter (single material buildup factor) that is to replace the existing material atomic number as an input parameter. The comparison of two models generated by different input parameters has been performed. The second goal is to improve the evolution process of learning, i.e., the experimental computational procedure that provides a framework for automated construction of complex regression models of predefined
Multi-Layer and Recursive Neural Networks for Metagenomic Classification.
Ditzler, Gregory; Polikar, Robi; Rosen, Gail
2015-09-01
Recent advances in machine learning, specifically in deep learning with neural networks, has made a profound impact on fields such as natural language processing, image classification, and language modeling; however, feasibility and potential benefits of the approaches to metagenomic data analysis has been largely under-explored. Deep learning exploits many layers of learning nonlinear feature representations, typically in an unsupervised fashion, and recent results have shown outstanding generalization performance on previously unseen data. Furthermore, some deep learning methods can also represent the structure in a data set. Consequently, deep learning and neural networks may prove to be an appropriate approach for metagenomic data. To determine whether such approaches are indeed appropriate for metagenomics, we experiment with two deep learning methods: i) a deep belief network, and ii) a recursive neural network, the latter of which provides a tree representing the structure of the data. We compare these approaches to the standard multi-layer perceptron, which has been well-established in the machine learning community as a powerful prediction algorithm, though its presence is largely missing in metagenomics literature. We find that traditional neural networks can be quite powerful classifiers on metagenomic data compared to baseline methods, such as random forests. On the other hand, while the deep learning approaches did not result in improvements to the classification accuracy, they do provide the ability to learn hierarchical representations of a data set that standard classification methods do not allow. Our goal in this effort is not to determine the best algorithm in terms accuracy-as that depends on the specific application-but rather to highlight the benefits and drawbacks of each of the approach we discuss and provide insight on how they can be improved for predictive metagenomic analysis. PMID:26316190
Tensile performance of braided composite rods for concrete reinforcement
Pereira, Cristiana Gonilho; Fangueiro, Raúl; Jalali, Said; Araújo, Mário Duarte de; Marques, P.
2008-01-01
The current work is concerned with the development of braided composite rods for civil engineering applications, namely for concrete internal reinforcement, as a steel substitute. The research study aims at understanding the tensile behaviour of composite rods reinforced by a textile structure – braided structure with core reinforcement. Seven types of braided composite rods were produced, varying the type of fibres used as a core reinforcement of a polyester braided structure. Eglass, car...
Braided composite rods to reinforce concrete subjected to aggressive environments
Pereira, Cristiana Gonilho; Fangueiro, Raúl; Jalali, Said; Marques, P.; Araújo, Mário Duarte de
2008-01-01
The current work is concerned with the development of braided composite rods for civil engineering applications, namely for concrete internal reinforcement, as a steel substitute. The research study aims at understanding the tensile behaviour of composite rods reinforced by a textile structure – braided structure with core reinforcement. Seven types of braided composite rods were produced, varying the type of fibres used as a core reinforcement of a polyester braided structure. E-glass, ca...
Diffusive evolution of experimental braided rivers
Reitz, Meredith D.; Jerolmack, Douglas J.; Lajeunesse, Eric; Limare, Angela; Devauchelle, Olivier; Métivier, François
2014-05-01
Water flowing over a loose granular bed organizes into a braided river, a network of ephemeral and interacting channels. The temporal and spatial evolution of this network of braided channels is not yet quantitatively understood. In ˜1 m-scale experiments, we found that individual channels exhibit a self-similar geometry and near-threshold transport conditions. Measurements of the rate of growth of topographic correlation length scales, the time scale of system-slope establishment, and the random spatial decorrelation of channel locations indicate together that the evolution of the braided river system may be diffusive in nature. This diffusion is due to the separation of scales between channel formation and network evolution, and the random motion of interacting channels when viewed at a coarse-grained scale.
Integrated Design for Manufacturing of Braided Preforms for Advanced Composites Part I: 2D Braiding
Gao, Yan Tao; Ko, Frank K.; Hu, Hong
2013-12-01
This paper presents a 2D braiding design system for advanced textile structural composites was based on dynamic models. A software package to assist in the design of braided preform manufacturing has been developed. The package allows design parameters (machine speeds, fiber volume fraction, tightness factor, etc.) to be easily obtained and the relationships between said parameters to be demonstrated graphically. The fabirc geometry model (FGM) method was adopted to evaluate the mechanical properties of the composites. Experimental evidence demonstrates the success of the use of dynamic models in the design software for the manufacture of braided fabric preforms.
Effect of braiding process on the damage tolerance of 3-D braided graphite/epoxy composites
El-Shiekh, Aly; Li, Wei; Hammad, Mohamed
1989-01-01
One of the key advantages of three-dimensional braided composite materials is their high impact damage tolerance comparing with laminated composites, due to their fully integrated fibrous substrates. In this paper, the effect of different processing methods on the impact damage tolerance of braided graphite/epoxy composite is experimentally assessed. The test specimens are prepared using both of the two existing three-dimensional braiding techniques (the 4-step and the 2-step processes). After the specimens are impacted under controlled impact energy, the damage introduced is studied. Then a compression test is conducted to evaluate the compression strength of the specimens after impact.
Positive braid knots of maximal topological 4-genus
Liechti, Livio
2015-01-01
We show that a positive braid knot has maximal topological 4-genus exactly if it has maximal signature invariant. As an application, we determine all positive braid knots with maximal topological 4-genus and compute the topological 4-genus for all positive braid knots with up to 12 crossings.
Braiding operator via quantum cluster algebra
International Nuclear Information System (INIS)
We construct a braiding operator in terms of the quantum dilogarithm function based on the quantum cluster algebra. We show that it is a q-deformation of the R-operator for which hyperbolic octahedron is assigned. Also shown is that, by taking q to be a root of unity, our braiding operator reduces to the Kashaev RK-matrix up to a simple gauge-transformation. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Cluster algebras in mathematical physics’. (paper)
Flexible organic light-emitting diodes with ITO/Ag/ITO multi-layers as anodes
Institute of Scientific and Technical Information of China (English)
LI Yang; WANG Liduo; CHANG Chun; DUAN Lian; QIU Yong
2004-01-01
The transparent ITO/Ag/ITO multi-layers are developed as anodes on flexible PET (poly(ethylene terephthalate)) substrates. The influence of these anodes on FOLED (Flexible Organic Light-emitting Diodes) is investigated. From the results of research, it can be seen that the multi-layer anode has optimum characteristics, whose sheet resistance is 11 Ω and optical transmittance is about 80%,when the thickness of Ag sandwiched by two ITO layers is in the range of 14-18 nm. It is demonstrated that the OLED devices with multi-layer anodes give better luminescence and higher efficiency compared with those with single ITO an odes.
A generalized combination equation derived from a multi-layer micrometeorological model
Lhomme, Jean-Paul
1988-10-01
The discrete multi-layer model originally devised by Waggoner and Reifsnyder (1968) is used as a theoretical basis to describe the vegetation-atmosphere interaction. Mathematical development of the basic equations yields Ohm's law-type formulae for sensible and latent heat fluxes from which it is possible to derive a combination equation very close in form to Penman-Monteith's equation. A bulk aerodynamic resistance and a bulk stomatal resistance can be defined and expressed in terms of the elementary resistances of the multi-layer model. This new combination equation offers an alternative to the attempts undertaken by Shuttleworth (1976) to unify multi-layer and single-layer approaches.
Statistical Model of the 3-D Braided Composites Strength
Institute of Scientific and Technical Information of China (English)
XIAO Laiyuan; ZUO Weiwei; CAI Ganwei; LIAO Daoxun
2007-01-01
Based on the statistical model for the tensile statistical strength of unidirectional composite materials and the stress analysis of 3-D braided composites, a new method is proposed to calculate the tensile statistical strength of the 3-D braided composites. With this method, the strength of 3-D braided composites can be calculated with very large accuracy, and the statistical parameters of 3-D braided composites can be determined. The numerical result shows that the tensile statistical strength of 3-D braided composites can be predicted using this method.
Experimental study of damage and destroy of X-ray multi-layer reflector
International Nuclear Information System (INIS)
The plasma environment which creates X-ray laser brings the difficulty to the application of X-ray multi-layer reflector. The most difficult is that the X-ray emitted by the plasma destroys and damages the multi-layer reflector. It is shown by the simulated test that the damaged threshold of Mo/Si multilayer reflector made in china is less than 0.10 J/cm2. With the exposure the radiation dose the rood-mean square roughness of multi-layer apparently increases and the reflectivity almost drops to zero. According to these results, the article state some ideas for preventing damages of the multi-layer reflector
Exploring multi-layer flow network of international trade based on flow distances
Shen, Bin; Zheng, Qiuhua
2015-01-01
Based on the approach of flow distances, the international trade flow system is studied from the perspective of multi-layer flow network. A model of multi-layer flow network is proposed for modelling and analyzing multiple types of flows in flow systems. Then, flow distances are introduced, and symmetric minimum flow distance is presented. Subsequently, we discuss the establishment of the multi-layer flow networks of international trade from two coupled viewpoints, i.e., the viewpoint of commodity flow and that of money flow. Thus, the multi-layer flow networks of international trade is explored. First, trading "trophic levels" are adopted to depict positions that economies occupied in the flow network. We find that the distributions of trading "trophic levels" have the similar clustering pattern for different types of commodity, and there are some regularities between money flow network and commodity flow network. Second, we find that active and competitive countries trade a wide spectrum of products, while ...
Load-Bearing Tank-Applied Multi-Layer Insulation Project
National Aeronautics and Space Administration — The proposed load-bearing, tank-applied, multi-layer insulation system consists of a set of highly reflective radiation shields made from 1 mil thick aluminized...
Synthesis and characterization of carbon/silica superhydrophobic multi-layer films
International Nuclear Information System (INIS)
C/SiO2 multi-layer films (3-layer films and 5-layer films) were obtained by sol-gel method and physical deposition on glass plates, and then heated at 500 oC for 1 h under a nitrogen atmosphere. The mechanical adhesive force with the substrate of the multi-layer films was sharply enhanced compared to the as-deposited amorphous carbon film. An absorption layer was formed on heat treated C/SiO2 multi-layer films by modification of the surface with trimethylchlorosilane, and the wettability of the films changed from hydrophilic to super-hydrophobic. The structures of the physically deposited carbon and the multi-layer films were analyzed by X-ray diffraction, transmission electron microscopy and scanning electron microscopy. The experimental results showed that the 5-layer films had a concentric ring structure that caused the film to be superhydrophobic.
Ferrofluids, complex particle dynamics and braid description
International Nuclear Information System (INIS)
Finely divided magnetic matter is important in many areas of science and technology. A special sub-class of systems are made up of freely moving particles suspended in a carrier liquid where the magnetic interactions play an important role in the actual structure formation and dynamical behaviour. These include ferrofluids, which are colloids of magnetic particles dispersed in carrier fluids, magnetic micro-beads, which are micrometer sized plastic beads loaded with iron oxide, and nonmagnetic particles dispersed in ferrofluids, forming the so-called 'magnetic holes'. How, in a simple and forceful way, is it possible to characterise the dynamics of systems with several moving components like dispersed magnetic particles subjected to external magnetic fields? The methods based on the theory of braids may provide the answer. Braid theory is a sub-field of mathematics known as topology. It involves classifying different ways of tracing curves in space. The topological description of braids thus provides a simple and concise language for describing the dynamics of a system of moving particles as if they perform a complicated dance as they move about one another, and the braid encodes the choreography of this dance
Ferrofluids, complex particle dynamics and braid description
Skjeltorp, Arne T.; Clausen, Sigmund; Helgesen, Geir
2001-05-01
Finely divided magnetic matter is important in many areas of science and technology. A special sub-class of systems are made up of freely moving particles suspended in a carrier liquid where the magnetic interactions play an important role in the actual structure formation and dynamical behaviour. These include ferrofluids, which are colloids of magnetic particles dispersed in carrier fluids, magnetic micro-beads, which are micrometer sized plastic beads loaded with iron oxide, and nonmagnetic particles dispersed in ferrofluids, forming the so-called "magnetic holes". How, in a simple and forceful way, is it possible to characterise the dynamics of systems with several moving components like dispersed magnetic particles subjected to external magnetic fields? The methods based on the theory of braids may provide the answer. Braid theory is a sub-field of mathematics known as topology. It involves classifying different ways of tracing curves in space. The topological description of braids thus provides a simple and concise language for describing the dynamics of a system of moving particles as if they perform a complicated dance as they move about one another, and the braid encodes the choreography of this dance.
Quantum Lorentz and braided Poincare groups
Zakrzewski, S.
1997-01-01
Quantum Lorentz groups H admitting quantum Minkowski space V are selected. Natural structure of a quantum space G = V x H is introduced, defining a quantum group structure on G only for triangular H (q=1). We show that it defines a braided quantum group structure on G for |q|=1.
DEFF Research Database (Denmark)
Andersen, Thomas Lykke; Skals, Kasper; Burcharth, Hans F.
2008-01-01
The paper deals with homogeneous and multi-layer berm breakwaters designed to maximize the utilization of the quarry material. Two wide stone classes are typically used for berm breakwaters with a homogeneous berm.......The paper deals with homogeneous and multi-layer berm breakwaters designed to maximize the utilization of the quarry material. Two wide stone classes are typically used for berm breakwaters with a homogeneous berm....
A simple multi-layer finite volume solver for density-driven shallow water flows.
Benkhaldoun, F.; Sari, S.; Seaid, M.
2014-01-01
A simple solver is proposed for the numerical solution of density-driven multi-layer shallow water flows. The governing equations consist on coupling the multi-layer shallow water equations for the hydraulic variables with suspended sediment transport equations for the concentration variables. The layers can be formed in the shallow water model based on the variation of water density which may depend on the water temperature and salinity. At each time step, the method consists of two stages t...
Damage effects on multi-layer graphene from femtosecond laser interaction
International Nuclear Information System (INIS)
We present a study on the damage effects of femtosecond laser interaction on exfoliated multi-layer graphene using the techniques of optical microscopy, atomic force microscopy, and Raman spectroscopy. Various effects of the interaction were observed. The ablation threshold was found to be ∼4 mJ cm−2, and was slightly higher in transmission mode than in reflection mode. This work also demonstrates the feasibility of ultrafast laser patterning of exfoliated multi-layer graphene. (paper)
Orientation in multi-layer chitosan hydrogel: morphology, mechanism, and design principle
Jingyi Nie; Wentao Lu; Jianjun Ma; Ling Yang; Zhengke Wang; An Qin; Qiaoling Hu
2015-01-01
Hydrogels with organized structure have attracted remarkable attentions for bio-related applications. Among the preparation of hierarchical hydrogel materials, fabrication of hydrogel with multi-layers is an important branch. Although the generation mechanism of layers had been fully discussed, sub-layer structure was not sufficiently studied. In this research, multi-layered chitosan hydrogel with oriented structure was constructed, and the formation mechanism of orientation was proposed, bas...
Null Models and Modularity Based Community Detection in Multi-Layer Networks
Paul, Subhadeep
2016-01-01
Multi-layer networks are networks on a set of entities (nodes) with multiple types of relations (edges) among them where each type of relation/interaction is represented as a network layer. As with single layer networks, community detection is an important task in multi-layer networks. A large group of popular community detection methods in networks are based on optimizing a quality function known as the modularity score, which is a measure of presence of modules or communities in networks. Hence a first step in community detection is defining a suitable modularity score that is appropriate for the network in question. Here we introduce several multi-layer network modularity measures under different null models of the network, motivated by empirical observations in networks from a diverse field of applications. In particular we define the multi-layer configuration model, the multi-layer expected degree model and their various modifications as null models for multi-layer networks to derive different modulariti...
Corrosion protected, multi-layer fuel cell interface
International Nuclear Information System (INIS)
A fuel cell stack is described comprising stacked elements, including at least one corrosion resistant, electrically conductive, fluid impervious interface arranged between two of the elements which are not adjacent to one another. The interface consists of a non-cupreous metal coating formed on at least one of the elements and a conductive layer bonded to at least the metal-coated element by a hot-pressed resin. The resin substantially fills any pores in the conductive layer
A Fully Self-consistent Multi-layered Model of Jupiter
Kong, Dali; Zhang, Keke; Schubert, Gerald
2016-08-01
We construct a three-dimensional, fully self-consistent, multi-layered, non-spheroidal model of Jupiter consisting of an inner core, a metallic electrically conducting dynamo region, and an outer molecular electrically insulating envelope. We assume that the Jovian zonal winds are on cylinders parallel to the rotation axis but, due to the effect of magnetic braking, are confined within the outer molecular envelope. We also assume that the location of the molecular-metallic interface is characterized by its equatorial radius {{HR}}e, where R e is the equatorial radius of Jupiter at the 1 bar pressure level and H is treated as a parameter of the model. We solve the relevant mathematical problem via a perturbation approach. The leading-order problem determines the density, size, and shape of the inner core, the irregular shape of the 1 bar pressure level, and the internal structure of Jupiter that accounts for the full effect of rotational distortion, but without the influence of the zonal winds; the next-order problem determines the variation of the gravitational field solely caused by the effect of the zonal winds on the rotationally distorted non-spheroidal Jupiter. The leading-order solution produces the known mass, the known equatorial and polar radii, and the known zonal gravitational coefficient J 2 of Jupiter within their error bars; it also yields the coefficients J 4 and J 6 within about 5% accuracy, the core equatorial radius 0.09{R}e and the core density {ρ }c=2.0× {10}4 {{kg}} {{{m}}}-3 corresponding to 3.73 Earth masses; the next-order solution yields the wind-induced variation of the zonal gravitational coefficients of Jupiter.
MultiLayer solid electrolyte for lithium thin film batteries
Energy Technology Data Exchange (ETDEWEB)
Lee, Se -Hee; Tracy, C. Edwin; Pitts, John Roland; Liu, Ping
2015-07-28
A lithium metal thin-film battery composite structure is provided that includes a combination of a thin, stable, solid electrolyte layer [18] such as Lipon, designed in use to be in contact with a lithium metal anode layer; and a rapid-deposit solid electrolyte layer [16] such as LiAlF.sub.4 in contact with the thin, stable, solid electrolyte layer [18]. Batteries made up of or containing these structures are more efficient to produce than other lithium metal batteries that use only a single solid electrolyte. They are also more resistant to stress and strain than batteries made using layers of only the stable, solid electrolyte materials. Furthermore, lithium anode batteries as disclosed herein are useful as rechargeable batteries.
Burst Testing of Triaxial Braided Composite Tubes
Salem, J. A.; Bail, J. L.; Wilmoth, N. G.; Ghosn, L. J.; Kohlman, L. W.; Roberts, G. D.; Martin, R. E.
2014-01-01
Applications using triaxial braided composites are limited by the materials transverse strength which is determined by the delamination capacity of unconstrained, free-edge tows. However, structural applications such as cylindrical tubes can be designed to minimize free edge effects and thus the strength with and without edge stresses is relevant to the design process. The transverse strength of triaxial braided composites without edge effects was determined by internally pressurizing tubes. In the absence of edge effects, the axial and transverse strength were comparable. In addition, notched specimens, which minimize the effect of unconstrained tow ends, were tested in a variety of geometries. Although the commonly tested notch geometries exhibited similar axial and transverse net section failure strength, significant dependence on notch configuration was observed. In the absence of unconstrained tows, failure ensues as a result of bias tow rotation, splitting, and fracture at cross-over regions.
Iadecola, Thomas; Schuster, Thomas; Chamon, Claudio
2016-08-01
Many topological phenomena first proposed and observed in the context of electrons in solids have recently found counterparts in photonic and acoustic systems. In this work, we demonstrate that non-Abelian Berry phases can arise when coherent states of light are injected into "topological guided modes" in specially fabricated photonic waveguide arrays. These modes are photonic analogues of topological zero modes in electronic systems. Light traveling inside spatially well-separated topological guided modes can be braided, leading to the accumulation of non-Abelian phases, which depend on the order in which the guided beams are wound around one another. Notably, these effects survive the limit of large photon occupation, and can thus also be understood as wave phenomena arising directly from Maxwell's equations, without resorting to the quantization of light. We propose an optical interference experiment as a direct probe of this non-Abelian braiding of light.
Braid group representation on quantum computation
International Nuclear Information System (INIS)
There are many studies about topological representation of quantum computation recently. One of diagram representation of quantum computation is by using ZX-Calculus. In this paper we will make a diagrammatical scheme of Dense Coding. We also proved that ZX-Calculus diagram of maximally entangle state satisfies Yang-Baxter Equation and therefore, we can construct a Braid Group representation of set of maximally entangle state
Braid group representation on quantum computation
Energy Technology Data Exchange (ETDEWEB)
Aziz, Ryan Kasyfil, E-mail: kasyfilryan@gmail.com [Department of Computational Sciences, Bandung Institute of Technology (Indonesia); Muchtadi-Alamsyah, Intan, E-mail: ntan@math.itb.ac.id [Algebra Research Group, Bandung Institute of Technology (Indonesia)
2015-09-30
There are many studies about topological representation of quantum computation recently. One of diagram representation of quantum computation is by using ZX-Calculus. In this paper we will make a diagrammatical scheme of Dense Coding. We also proved that ZX-Calculus diagram of maximally entangle state satisfies Yang-Baxter Equation and therefore, we can construct a Braid Group representation of set of maximally entangle state.
MULTI-LAYER PIEZOELECTRIC ACTUATOR AND ITS APPLICATION IN CONTROLLABLE CONSTRAINED DAMPING TREATMENT
Institute of Scientific and Technical Information of China (English)
ZHANG Xinong; XIE Shilin; ZHANG Yahong
2007-01-01
A kind of novel multi-layer piezoelectric actuator is proposed and integrated with controllable constrained damping treatment to perform hybrid Vibration control. The governing equation of the System is derived based on the constitutive equations of elastic, viscoelastic and piezoelectric materials, which shows that the magnitude of control force exerted by multi-layer piezoelectric actuator is the quadratic function of the number of piezoelectric laminates used but in direct proportion to control voltage. This means that the multi-layer actuator can produce greater actuating force than that by piezoelectric laminate actuator with the same area under the identical control voltage. The optimal location placement of the multi-layer piezoelectric actuator is also discussed. As an example, the hybrid Vibration control of a cantilever rectangular thin-plate is numerically simulated and carried out experimentally. The simulated and experimental results validate the power of multi-layer piezoelectric actuator and indicate that the present hybrid damping technique can effectively suppress the low frequency modal Vibration of the experimental thin-plate structure.
Geometric representations of the braid groups
Castel, Fabrice
2011-01-01
We show that the morphisms from the braid group with n strands in the mapping class group of a surface with a possible non empty boundary, assuming that its genus is smaller or equal to n/2 are either cyclic morphisms (their images are cyclic groups), or transvections of monodromy morphisms (up to multiplication by an element in the centralizer of the image, the image of a standard generator of the braid group is a Dehn twist, and the images of two consecutive standard generators are two Dehn twists along two curves intersecting in one point). As a corollary, we determine the endomorphisms, the injective endomorphisms, the automorphisms and the outer automorphism group of the following groups: the braid group with n strands where n is greater than or equal to 6, and the mapping class group of any surface of genus greater or equal than 2. For each statement involving the mapping class group, we study both cases: when the boundary is fixed pointwise, and when each boundary component is fixed setwise. We will al...
Imperfect dark energy from kinetic gravity braiding
International Nuclear Information System (INIS)
We introduce a large class of scalar-tensor models with interactions containing the second derivatives of the scalar field but not leading to additional degrees of freedom. These models exhibit peculiar features, such as an essential mixing of scalar and tensor kinetic terms, which we have named kinetic braiding. This braiding causes the scalar stress tensor to deviate from the perfect-fluid form. Cosmology in these models possesses a rich phenomenology, even in the limit where the scalar is an exact Goldstone boson. Generically, there are attractor solutions where the scalar monitors the behaviour of external matter. Because of the kinetic braiding, the position of the attractor depends both on the form of the Lagrangian and on the external energy density. The late-time asymptotic of these cosmologies is a de Sitter state. The scalar can exhibit phantom behaviour and is able to cross the phantom divide with neither ghosts nor gradient instabilities. These features provide a new class of models for Dark Energy. As an example, we study in detail a simple one-parameter model. The possible observational signatures of this model include a sizeable Early Dark Energy and a specific equation of state evolving into the final de-Sitter state from a healthy phantom regime
International Nuclear Information System (INIS)
This research thesis reports the characterization of anti-corrosion titanium and aluminium coatings deposited on a 35CD4 steel under the form of mono-metallic layers or alternated Ti/Al multi-layers, and obtained by a multibeam PVD technique. The influence of different parameters is studied: single-layer thickness (5, 15 or 30 micro-metres), multi-layer distribution (5 to 6) and substrate (smooth or threaded). Layer nature and microstructure are studied by optical microscopy and scanning electron microscopy (SEM), as well as corrosion toughness in aqueous saline environments. Coated threaded samples have been studied after tightening tests. It appears that titanium layers are denser and more uniform than aluminium layers, and that multi-layer coatings provide a better protection than single-layer coatings. The best behaviour is obtained when titanium is in contact with steel, and aluminium is the outer layer in contact with the corroding environment
Teleportation, Braid Group and Temperley--Lieb Algebra
Zhang, Yong
2006-01-01
We explore algebraic and topological structures underlying the quantum teleportation phenomena by applying the braid group and Temperley--Lieb algebra. We realize the braid teleportation configuration, teleportation swapping and virtual braid representation in the standard description of the teleportation. We devise diagrammatic rules for quantum circuits involving maximally entangled states and apply them to three sorts of descriptions of the teleportation: the transfer operator, quantum mea...
CAD/CAM of braided preforms for advanced composites
Yang, Gui; Pastore, Christopher; Tsai, Yung Jia; Soebroto, Heru; Ko, Frank
A CAD/CAM system for braiding to produce preforms for advanced textile structural composites is presented in this paper. The CAD and CAM systems are illustrated in detail. The CAD system identifies the fiber placement and orientation needed to fabricate a braided structure over a mandrel, for subsequent composite formation. The CAM system uses the design parameters generated by the CAD system to control the braiding machine. Experimental evidence demonstrating the success of combining these two technologies to form a unified CAD/CAM system for the manufacture of braided fabric preforms with complex structural shapes is presented.
Self-organized braiding in solar coronal loops
Berger, M. A.; Asgari-Targhi, M.; Deluca, E. E.
2015-08-01
In this paper, we investigate the evolution of braided solar coronal loops. We assume that coronal loops consist of several internal strands which twist and braid about each other. Reconnection between the strands leads to small flares and heating of the loop to x-ray temperatures. Using a method of generating and releasing braid structure similar to a forest fire model, we show that the reconnected field lines evolve to a self-organised critical state. In this state, the frequency distributions of coherent braid sequences as well as flare energies follow power law distributions. We demonstrate how the presence of net helicity in the loop alters the distribution laws.
A new algebra which transmutes to the braided algebra
Yildiz, A
1999-01-01
We find a new braided Hopf structure for the algebra satisfied by the entries of the braided matrix $BSL_q(2)$. A new nonbraided algebra whose coalgebra structure is the same as the braided one is found to be a two parameter deformed algebra. It is found that this algebra is not a comodule algebra under adjoint coaction. However, it is shown that for a certain value of one of the deformation parameters the braided algebra becomes a comodule algebra under the coaction of this nonbraided algebr...
Braiding in Conformal Field Theory and Solvable Lattice Models
Gepner, D; Gepner, Doron; Fuchs, Jurgen
1994-01-01
Braiding matrices in rational conformal field theory are considered. The braiding matrices for any two block four point function are computed, in general, using the holomorphic properties of the blocks and the holomorphic properties of rational conformal field theory. The braidings of $SU(N)_k$ with the fundamental are evaluated and are used as examples. Solvable interaction round the face lattice models are constructed from these braiding matrices, and their Boltzmann weights are given. This allows, in particular, for the derivation of the Boltzmann weights of such solvable height models.
Institute of Scientific and Technical Information of China (English)
Xianghua LI; Xiaohui LIU; Shenfang YUAN
2008-01-01
The experimental characterization of three-dimensional (3-D) braided composites is extremely important for their design and analysis. Because of their desirable attributes and outstanding performance, optical fiber sensors (OFSs) can be embedded to mon-itor mechanical properties of textile composites. This paper discusses two techniques to incorporate different OFSs into 3-D braided composite preforms. The oper-ating principle of various sensor systems is first con-ducted. Experiments using Michelson interferometers, FBG sensors, and micro-bend sensors are performed to verify the concept of the proposed method. Strain curves of various OFSs tests are finally compared, and they all exhibit good linearity.
Multi-Layered Films Containing a Biomimetic Stimuli-Responsive Recombinant Protein
Barbosa, J. S.; Costa, R. R.; Testera, A. M.; Alonso, M.; Rodríguez-Cabello, J. C.; Mano, J. F.
2009-10-01
Electrostatic self-assembly was used to fabricate new smart multi-layer coatings, using a recombinant elastin-like polymer (ELP) and chitosan as the counterion macromolecule. The ELP was bioproduced, purified and its purity and expected molecular weight were assessed. Aggregate size measurements, obtained by light scattering of dissolved ELP, were performed as a function of temperature and pH to assess the smart properties of the polymer. The build-up of multi-layered films containing ELP and chitosan, using a layer-by-layer methodology, was followed by quartz-crystal microbalance with dissipation monitoring. Atomic force microscopy analysis permitted to demonstrate that the topography of the multi-layered films could respond to temperature. This work opens new possibilities for the use of ELPs in the fabrication of biodegradable smart coatings and films, offering new platforms in biotechnology and in the biomedical area.
Stresses in heated pressurized multi-layer cylinders in generalized plane strain conditions
International Nuclear Information System (INIS)
An analytical solution for the displacement field and corresponding stress state in multi-layer cylinders subjected to pressure and thermal loading is developed. Solutions are developed for axially loaded and spring-mounted cylinders, assuming that the combined multi-layer cross-section remains plane after deformation (generalized plane strain). The analytical solutions are verified by means of detailed three-dimensional finite element analyses. The solutions are easily implemented in, and suitable for, engineering applications. - Highlights: • An analytical solution for heated pressurized multi-layer cylinders is developed. • The solution is easily implemented and computationally efficient. • The solution highlights application to coated pipelines. • The analytical solution is verified numerically by finite element analyses
Can we neglect the multi-layer structure of functional networks?
Zanin, Massimiliano
2015-01-01
Functional networks, i.e. networks representing dynamic relationships between the components of a complex system, have been instrumental for our understanding of, among others, the human brain. Due to limited data availability, the multi-layer nature of numerous functional networks has hitherto been neglected, and nodes are endowed with a single type of links even when multiple relationships coexist at different physical levels. A relevant problem is the assessment of the benefits yielded by studying a multi-layer functional network, against the simplicity guaranteed by the reconstruction and use of the corresponding single layer projection. Here, I tackle this issue by using as a test case, the functional network representing the dynamics of delay propagation through European airports. Neglecting the multi-layer structure of a functional network has dramatic consequences on our understanding of the underlying system, a fact to be taken into account when a projection is the only available information.
Reed, Heather; Hoppe, Wally
2016-02-01
Thermographic NDE approaches to detect subsurface corrosion defects of multi-layered structures with composite top layers have proven difficult due to the fact that the thermal conductivity of composite materials is larger in lateral directions (the plane parallel to the surface) than in the through-thickness directions. This causes heat to dissipate faster laterally than through the thickness when a heat source is applied to the surface of the structure, making it difficult for subsurface damage effects to manifest on the surface, where the heat source and inspection typically occur. To address this, a heat induction approach is presented that excites the damaged, metallic bottom layer directly by Joule heating, resulting in more observable damage effects on the surface than what could be expected for traditional thermographic methods on this type of structure. To characterize the subsurface damage parameters (defect location, diameter, and depth), Bayesian inversion of numerically-simulated noisy data, using a high-fidelity, coupled electromagnetic-heat transfer model is employed. Stochastic estimation methods such as Markov chain Monte Carlo (MCMC) allow for quantification of uncertainty surrounding the damage parameters, which is important as this directly translates into uncertainty surrounding the component reliability. However, because thousands of high-fidelity finite element models are computationally costly to evaluate, as is typical in most MCMC methods, the use of Bayesian inversion is rarely feasible in real-time. To address this, a projection-based reduced order modeling (ROM) tracking and interpolation scheme is formulated within the MCMC sampling method for the multi-physics problem, resulting in significant speedup of solution time with little loss of accuracy, enabling near-real time stochastic estimation of damage.
Thermoelectric characteristics of Pt-silicide/silicon multi-layer structured p-type silicon
International Nuclear Information System (INIS)
Electric and thermoelectric properties of silicide/silicon multi-layer structured devices were investigated with the variation of silicide/silicon heterojunction numbers from 3 to 12 layers. For the fabrication of silicide/silicon multi-layered structure, platinum and silicon layers are repeatedly sputtered on the (100) silicon bulk substrate and rapid thermal annealing is carried out for the silicidation. The manufactured devices show ohmic current–voltage (I–V) characteristics. The Seebeck coefficient of bulk Si is evaluated as 195.8 ± 15.3 μV/K at 300 K, whereas the 12 layered silicide/silicon multi-layer structured device is evaluated as 201.8 ± 9.1 μV/K. As the temperature increases to 400 K, the Seebeck coefficient increases to 237.2 ± 4.7 μV/K and 277.0 ± 1.1 μV/K for bulk and 12 layered devices, respectively. The increase of Seebeck coefficient in multi-layered structure is mainly attributed to the electron filtering effect due to the Schottky barrier at Pt-silicide/silicon interface. At 400 K, the thermal conductivity is reduced by about half of magnitude compared to bulk in multi-layered device which shows the efficient suppression of phonon propagation by using Pt-silicide/silicon hetero-junctions. - Highlights: • Silicide/silicon multi-layer structured is proposed for thermoelectric devices. • Electric and thermoelectric properties with the number of layer are investigated. • An increase of Seebeck coefficient is mainly attributed the Schottky barrier. • Phonon propagation is suppressed with the existence of Schottky barrier. • Thermal conductivity is reduced due to the suppression of phonon propagation
Energy Technology Data Exchange (ETDEWEB)
Vokkarane, Vinod [University of Massachusetts
2013-09-01
We intend to implement a Coordinated Multi-layer Multi-domain Optical Network (COMMON) Framework for Large-scale Science Applications. In the COMMON project, specific problems to be addressed include 1) anycast/multicast/manycast request provisioning, 2) deployable OSCARS enhancements, 3) multi-layer, multi-domain quality of service (QoS), and 4) multi-layer, multidomain path survivability. In what follows, we outline the progress in the above categories (Year 1, 2, and 3 deliverables).
A study on elastic guided wave propagation in multi-layered structures
International Nuclear Information System (INIS)
In this study, we have developed a program which can calculate phase and group velocities, attenuation and wave structures of each mode in multi-layered plates. The wave structures of each mode are obtained, varying material properties and number of layers. The correlation between attenuation and out of plane displacement is also explored. It Is shown that to improve understanding on guided wave modal characteristics is possible by evaluating corresponding wave structures. Though this study, the concept to optimize guided wave mode selection is accomplished to enhance sensitivity and efficiency in nondestructive evaluation for multi-layered structures.
Collaborative-Hybrid Multi-Layer Network Control for Emerging Cyber-Infrastructures
Energy Technology Data Exchange (ETDEWEB)
Lehman, Tom [USC; Ghani, Nasir [UNM; Boyd, Eric [UCAID
2010-08-31
At a high level, there were four basic task areas identified for the Hybrid-MLN project. They are: o Multi-Layer, Multi-Domain, Control Plane Architecture and Implementation, including OSCARS layer2 and InterDomain Adaptation, Integration of LambdaStation and Terapaths with Layer2 dynamic provisioning, Control plane software release, Scheduling, AAA, security architecture, Network Virtualization architecture, Multi-Layer Network Architecture Framework Definition; o Heterogeneous DataPlane Testing; o Simulation; o Project Publications, Reports, and Presentations.
Discussion on in-situ leach mining of multi-layer deposit
International Nuclear Information System (INIS)
Along with increasing of multi-layer uranium sandstone deposits, investigation and test of mining technology have been seriously regarded, particular for separated mining at different stages. Although the mining is influenced by resources distribution in layers and mine capacity, relationship between aquifer and ore layer, mining sequence among layers, life of drilling hole etc., the mining for multi-layer sandstone deposits, no matter upper layer or lower layer is firstly mined, can be realized by use of PVC separator for well construction. (authors)
Failure of multi-layer graphene coatings in acidic media
DEFF Research Database (Denmark)
Yu, Feng; Stoot, Adam Carsten; Bøggild, Peter;
2016-01-01
Being impermeable to all gases, graphene has been proposed as an effective ultrathin barrier film and protective coating. However, here it is shown how the gastight property of graphene-based coatings may indirectly lead to their catastrophic failure under certain conditions. When nickel coated...... with thick, high-quality chemical vapor deposited multilayered graphene is exposed to acidic solutions, a dramatic evolution of gas is observed at the coating–substrate interface. The gas bubbles grow and merge, eventually rupturing and delaminating the coating. This behavior, attributed to cathodic...... hydrogen evolution, can also occur spontaneously on a range of other technologically important metals and alloys based on iron, zinc, aluminum and manganese; this makes these findings relevant for practical applications of graphene-based coatings.Being impermeable to all gases, graphene has been proposed...
Nondestructive testing of multi-layer tubes during fabrication
International Nuclear Information System (INIS)
Design of multilayer steel tubes for gas pipelines and technology of their fabrication are described in brief. Testing of the ground metal and welded joints of tubes used in their fabrication are considered. These methods comprise ultrasonic (US) testing of band, US testing and vacuum-bubble testing (VBT) of inner lap joints of shells X-ray TV control (XTVC) of ring welds, US testing of edge sections of shells with a continuous wall. Equipment applied in testing is described. XTVC is exercised by means of the RUP-150/300-10 X-ray apparatus, RI-60TEh introscope, sensitivity of testing is not worse than 4%, the rate equals 1-2 m/min
A study of mixing in coherent vortices using braiding factors
International Nuclear Information System (INIS)
This paper studies the use of braiding fluid particles to quantify the amount of mixing within a fluid flow. We analyze the pros and cons of braid methods by considering the motion of three or more fluid particles in a coherent vortex structure. The relative motions of the particles, as seen in a space-time diagram, produce a braid pattern, which is correlated with mixing and measured by the braiding factor. The flow we consider is a Gaussian vortex within a rotating strain field that generates cat's eyes in the vortex. We also consider a modified version of this strain field that contains a resonance frequency effect that produces multiple sets of cat's eyes at different radii. As the thickness of the cat's eyes increases, they interact with one another and produce complex Lagrangian motion in the flow that increases the braiding of particles, hence implying more mixing within the vortex. It is found that calculating the braiding factor using only three fluid particles gives useful information about the flow, but only if all three particles lie in the same region of the flow, i.e. this gives good local information. We find that we only require one of the three particles to trace a chaotic path to give an exponentially growing braiding factor. i.e. a non-zero 'braiding exponent'. A modified braiding exponent is also introduced which removes the spurious effects caused by the rotation of the fluid. This analysis is extended to a more global approach by using multiple fluid particles that span larger regions of the fluid. Using these global results, we compare the braiding within a viscously spreading Gaussian vortex in the above strain fields, where the flow is determined both kinematically and dynamically. We show that the dynamic feedback of the strain field onto the flow field reduces the overall amount of braiding of the fluid particles.
Design of bending multi-layer electroactive polymer actuators
Balakrisnan, Bavani; Nacev, Alek; Smela, Elisabeth
2015-04-01
The effects of layer thickness and stiffness on multilayer bending actuator performance were investigated with an analytical mechanical model. Performance was evaluated in terms of curvature, blocked force, and work. Multilayer device designs corresponding to dielectric elastomer actuator, ionic polymer metal composite, and conjugated polymer structures were examined. Normalized plots of the performance metrics as functions of relative layer thickness and stiffness are presented that should allow initial, starting-point estimates for designs for particular applications. The results show that to achieve high curvature, layer thickness and stiffness may need to be set above or below particular bounds, or varied together, depending on the device configuration; often there is a broad plateau of combinations that work equally well. There is a conflict between achieving high bending and high force: the former requires the device to behave as much as possible like a simple bilayer with optimal ratios of thickness and modulus, while the latter requires thicker layers and shows little dependence on their moduli. Finally, to maximize work there are areas in the thickness-modulus plane that should be avoided, these areas varying with the configuration in sometimes surprising ways.
Unraveling "Braid": Puzzle Games and Storytelling in the Imperative Mood
Arnott, Luke
2012-01-01
"Unraveling Braid" analyzes how unconventional, non-linear narrative fiction can help explain the ways in which video games signify. Specifically, this essay looks at the links between the semiotic features of Jonathan Blow's 2008 puzzle-platform video game Braid and similar elements in Georges Perec's 1978 novel "Life A User's Manual," as well as…
Sharing the Arts of the Blue Ridge Mountains. Rug Braiding.
Holman, Martha; Gailey, Lamar
This module on rug braiding is one of eight modules designed to provide instruction on authentic Blue Ridge Mountain crafts to adult basic education students at low cost. Contents include notes on the history of rug braiding; process used, including equipment and materials, as well as method described narratively and graphically; and the followup,…
Martínez, Ricardo; Casellas, Ramon; Muñoz, Raül
2013-03-11
We present the implementation of the GMPLS control plane functions and path computation algorithm deployed within the CTTC ADRENALINE testbed for the dynamic integrated restoration in multi-layer (MPLS-TP over WSON) networks. The experimental assessment is conducted in terms of the blocking probability, path computation time, restorability and restoration time. PMID:23482119
International Nuclear Information System (INIS)
Diatoms have delicate porous structures which are very beneficial in improving the absorbing ability in the bio-detection field. In this study, multi-layered hierarchical arrays were fabricated by packing Nitzschia soratensis (N. soratensis) frustules into Cosinodiscus argus (C. argus) frustules to achieve advanced sensitivity in bio-detection chips. Photolithographic patterning was used to obtain N. soratensis frustule arrays, and the floating behavior of C. argus frustules was employed to control their postures for packing N. soratensis frustule array spots. The morphology of the multi-layer C. argus–N. soratensis package array was investigated by scanning electron microscopy, demonstrating that the overall and sub-structures of the diatom frustules were retained. The signal enhancing effect of multi-layer C. argus–N. soratensis packages was demonstrated by fluorescent antibody test results. The mechanism of the enhancement was also analyzed, indicating that both complex hierarchical frustule structures and optimized posture of C. argus frustules were important for improving bio-detection sensitivities. The technique for fabricating multi-layer diatom frustules arrays is also useful for making multi-functional biochips and controllable drug delivery systems. (paper)
Electrohydrodynamic direct—writing of conductor—insulator-conductor multi-layer interconnection
International Nuclear Information System (INIS)
A multi-layer interconnection structure is a basic component of electronic devices, and printing of the multi-layer interconnection structure is the key process in printed electronics. In this work, electrohydrodynamic direct-writing (EDW) is utilized to print the conductor—insulator—conductor multi-layer interconnection structure. Silver ink is chosen to print the conductor pattern, and a polyvinylpyrrolidone (PVP) solution is utilized to fabricate the insulator layer between the bottom and top conductor patterns. The influences of EDW process parameters on the line width of the printed conductor and insulator patterns are studied systematically. The obtained results show that the line width of the printed structure increases with the increase of the flow rate, but decreases with the increase of applied voltage and PVP content in the solution. The average resistivity values of the bottom and top silver conductor tracks are determined to be 1.34 × 10−7 Ω·m and 1.39 × 10−7 Ω·m, respectively. The printed PVP layer between the two conductor tracks is well insulated, which can meet the insulation requirement of the electronic devices. This study offers an alternative, fast, and cost-effective method of fabricating conductor—insulator—conductor multi-layer interconnections in the electronic industry
Meyer-Plath, Asmus; Beckert, Fabian; Tölle, Folke J.; Sturm, Heinz; Mülhaupt, Rolf
2016-02-01
A process was developed for graphite particle exfoliation in water to stably dispersed multi-layer graphene. It uses electrohydraulic shockwaves and the functionalizing effect of solution plasma discharges in water. The discharges were excited by 100 ns high voltage pulsing of graphite particle chains that bridge an electrode gap. The underwater discharges allow simultaneous exfoliation and chemical functionalization of graphite particles to partially oxidized multi-layer graphene. Exfoliation is caused by shockwaves that result from rapid evaporation of carbon and water to plasma-excited gas species. Depending on discharge energy and locus of ignition, the shockwaves cause stirring, erosion, exfoliation and/or expansion of graphite flakes. The process was optimized to produce long-term stable aqueous dispersions of multi-layer graphene from graphite in a single process step without requiring addition of intercalants, surfactants, binders or special solvents. A setup was developed that allows continuous production of aqueous dispersions of flake size-selected multi-layer graphenes. Due to the well-preserved sp2-carbon structure, thin films made from the dispersed graphene exhibited high electrical conductivity. Underwater plasma discharge processing exhibits high innovation potential for morphological and chemical modifications of carbonaceous materials and surfaces, especially for the generation of stable dispersions of two-dimensional, layered materials.
Evaluation of Multi Layers Web-based GIS Approach in Retrieving Tourist Related Information
Directory of Open Access Journals (Sweden)
Rosilawati Zainol
2014-02-01
Full Text Available Geo-based information is getting greater importance among tourists. However, retrieving this information on the web depends heavily on the methods of dissemination. Therefore, this study intends to evaluate methods used in disseminating tourist related geo-based information on the web using partial match query, firstly, in default system which is a single layer approach and secondly, using multi layer web-based Geographic Information System (GIS approaches. Shah Alam tourist related data are used as a test collection and are stored in a map server. Query keyword is tested using both default and multi layer systems and results are evaluated using experiments on sample data. Precision and recall are the performance measurement technique used. Findings show that multi layer web-based GIS provide enhanced capability in retrieving tourist related information as compared to default system. Therefore, in the future, web-based GIS development should utilize multi layers approach instead of the single layer method in disseminating geo-based information to users.
Demonstrating multi-layered MAS in control of offshore oil and gas production
DEFF Research Database (Denmark)
Lindegaard Mikkelsen, Lars; Næumann, J. R.; Demazeau, Y.;
2013-01-01
From a control perspective, offshore oil and gas production is very challenging due to the many and potentially conflicting production objectives that arise from the intrinsic complexity of the oil and gas domain. In this paper, we demonstrate how a multi-layered multi-agent system can be used in a...
Multi-layered satisficing decision making in oil and gas production platforms
DEFF Research Database (Denmark)
Lindegaard Mikkelsen, Lars; Demazeau, Yves; Jørgensen, B. N.
2013-01-01
From a control perspective, offshore oil and gas production is very challenging due to the many and potentially conflicting production objectives that arise from the intrinsic complexity of the oil and gas domain. In this paper, we show how a multi-layered multi-agent system can be used to...
International Nuclear Information System (INIS)
A process was developed for graphite particle exfoliation in water to stably dispersed multi-layer graphene. It uses electrohydraulic shockwaves and the functionalizing effect of solution plasma discharges in water. The discharges were excited by 100 ns high voltage pulsing of graphite particle chains that bridge an electrode gap. The underwater discharges allow simultaneous exfoliation and chemical functionalization of graphite particles to partially oxidized multi-layer graphene. Exfoliation is caused by shockwaves that result from rapid evaporation of carbon and water to plasma-excited gas species. Depending on discharge energy and locus of ignition, the shockwaves cause stirring, erosion, exfoliation and/or expansion of graphite flakes. The process was optimized to produce long-term stable aqueous dispersions of multi-layer graphene from graphite in a single process step without requiring addition of intercalants, surfactants, binders or special solvents. A setup was developed that allows continuous production of aqueous dispersions of flake size-selected multi-layer graphenes. Due to the well-preserved sp2-carbon structure, thin films made from the dispersed graphene exhibited high electrical conductivity. Underwater plasma discharge processing exhibits high innovation potential for morphological and chemical modifications of carbonaceous materials and surfaces, especially for the generation of stable dispersions of two-dimensional, layered materials. (paper)
A novel multi-layer manifold microchannel cooling system for concentrating photovoltaic cells
International Nuclear Information System (INIS)
Highlights: • A multi-layer manifold microchannel cooling system was fabricated for CPV cells. • The unique multi-layer design can result in the higher heat transfer coefficient. • A higher net output power for CPV cell was achieved. - Abstract: Using concentrating photovoltaic (CPV) cells is an effective method for the low-cost photovoltaic conversion. However, higher temperature and non-uniform surface temperature distribution will result in the electrical output decline of CPV cells and shorten their life time. To obtain higher net output power of CPV cells and prolong their life time, we designed a novel multi-layer manifold microchannel cooling system to effectively lower the cell surface temperature and improve the uniformity of surface temperature distribution. Thermal image analysis indicated that the surface temperature difference of the CPV cells was below 6.3 °C. The multi-layer manifold microchannel had a heat transfer coefficient of 8235.84 W/m2 K and its pressure drop was lower than 3 kPa. The results show that the hybrid CPV cells have a satisfactory net output power due to their lower pumping power and the higher electrical output of CPV cells
Institute of Scientific and Technical Information of China (English)
Zheng-gang XIAO; San-jiu YING; Fu-ming XU
2014-01-01
Both heating and solvent-spray methods are used to consolidate the standard grains of double-base oblate sphere propellants plasticized with triethyleneglycol dinitrate (TEGDN) (TEGDN propellants) to high density propellants. The obtained consolidated propellants are deterred and coated with the slow burning multi-layer coating. The maximum compaction density of deterred and coated consolidated propellants can reach up to 1.39 g/cm3. Their mechanic, deconsolidation and combustion performances are tested by the materials test machine, interrupted burning set-up and closed vessel, respectively. The static compression strength of consolidated propellants deterred by multi-layer coating increases significantly to 18 MPa, indicating that they can be applied in most circumstances of charge service. And the samples are easy to deconsolidate in the interrupted burning test. Furthermore, the closed bomb burning curves of the samples indicate a two-stage combustion phenomenon under the condition of certain thickness of coated multi-layers. After the outer deterred multi-layer coating of consolidated samples is finished burning, the inner consolidated propellants continue to burn and breakup into aggregates and grains. The high burning progressivity can be carefully obtained by the smart control of deconsolidation process and duration of consolidated propellants. The preliminary results of consolidated propellants show that a rapid deconsolidation process at higher deconsolidation pressure is presented in the dynamic vivacity curves of closed bomb test. Higher density and higher macro progressivity of consolidated propellants can be obtained by the techniques in this paper.
Application of Multi-Layered Polyurethane Foams for Flat-Walled Anechoic Linings
DEFF Research Database (Denmark)
Xu, J. F.; Buchholz, Jörg; Fricke, Fergus R.
2006-01-01
application of multi-layered polyurethane foams as the flat-walled anechoic lining. The investigation includes aspects such as the efficacy of a single layer of material, the minimum number of layers of linings to achieve the minimum overall thickness for low (100Hz), mid (250Hz) and high (500Hz) cut...
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.
Comparative proteome analysis of multi-layer cocoon of the silkworm, Bombyx mori.
Zhang, Yan; Zhao, Ping; Dong, Zhaoming; Wang, Dandan; Guo, Pengchao; Guo, Xiaomeng; Song, Qianru; Zhang, Weiwei; Xia, Qingyou
2015-01-01
Bombyx mori cocoon has a multi-layer structure that provides optimal protection for silkworm pupa. Research on the mechanical properties of the multi-layer structure revealed structure-property relationships of the cocoon. Here, we investigated the protein components of the B. mori cocoon in terms of its multi-layer structure. Liquid chromatography-tandem mass spectrometry identified 286 proteins from the multiple cocoon layers. In addition to fibroins and sericins, we identified abundant protease inhibitors, seroins and proteins of unknown function. By comparing protein abundance across layers, we found that the outermost layer contained more sericin1 and protease inhibitors and the innermost layer had more seroin1. As many as 36 protease inhibitors were identified in cocoons, showing efficient inhibitory activities against a fungal protease. Thus, we propose that more abundant protease inhibitors in the outer cocoon layers may provide better protection for the cocoon. This study increases our understanding of the multi-layer mechanism of cocoons, and helps clarify the biological characteristics of cocoons. The data have been deposited to the ProteomeXchange with identifier PXD001469. PMID:25860555
SAPIR - Executing complex similarity queries over multi layer P2P search structures
Falchi, Fabrizio; Batko, Michal
2009-01-01
This deliverable reports the activities conducted within Task 5.4 "Executing complex similarity queries over multi layer P2P search structures" of the SAPIR project. In particular the deliverable discusses complex similarity queries issues and the implementation of the query processing over the P2P indexing. The document is accompanied by a zip file containing the javadoc for MUFIN.
Hybrid Multi-Layer Network Control for Emerging Cyber-Infrastructures
Energy Technology Data Exchange (ETDEWEB)
Summerhill, Richard
2009-08-14
There were four basic task areas identified for the Hybrid-MLN project. They are: o Multi-Layer, Multi-Domain, Control Plane Architecture and Implementation, o Heterogeneous DataPlane Testing, o Simulation, o Project Publications, Reports, and Presentations.
Road and Obstacle Detection Based on Multi-layer Laser Radar in Driverless Car
Duan, Jianmin; ZHENG Kaihua; SHI Lixiao
2015-01-01
To make a driverless car with better environment awareness, multi-layer laser radar was applied to detect roads and obstacles. Firstly the road edge data set was extracted from numerous laser radar data based on characteristics of the road edge data, and the cluster analysis of the data sets was done with the improved COBWEB algorithm based on Euclidean distance.
Electrohydrodynamic direct—writing of conductor—insulator-conductor multi-layer interconnection
Zheng, Gao-Feng; Pei, Yan-Bo; Wang, Xiang; Zheng, Jian-Yi; Sun, Dao-Heng
2014-06-01
A multi-layer interconnection structure is a basic component of electronic devices, and printing of the multi-layer interconnection structure is the key process in printed electronics. In this work, electrohydrodynamic direct-writing (EDW) is utilized to print the conductor—insulator—conductor multi-layer interconnection structure. Silver ink is chosen to print the conductor pattern, and a polyvinylpyrrolidone (PVP) solution is utilized to fabricate the insulator layer between the bottom and top conductor patterns. The influences of EDW process parameters on the line width of the printed conductor and insulator patterns are studied systematically. The obtained results show that the line width of the printed structure increases with the increase of the flow rate, but decreases with the increase of applied voltage and PVP content in the solution. The average resistivity values of the bottom and top silver conductor tracks are determined to be 1.34 × 10-7 Ω·m and 1.39 × 10-7 Ω·m, respectively. The printed PVP layer between the two conductor tracks is well insulated, which can meet the insulation requirement of the electronic devices. This study offers an alternative, fast, and cost-effective method of fabricating conductor—insulator—conductor multi-layer interconnections in the electronic industry.
Braids as a representation space of SU(5)
Cartin, Daniel
2015-01-01
The Standard Model of particle physics provides very accurate predictions of phenomena occurring at the sub-atomic level, but the reason for the choice of symmetry group and the large number of particles considered elementary, is still unknown. Along the lines of previous preon models positing a substructure to explain these aspects, Bilson-Thompson showed how the first family of elementary particles is realized as the crossings of braids made of three strands, with charges resulting from twists of those strands with certain conditions; in this topological model, there are only two distinct neutrino states. Modeling the particles as braids implies these braids must be the representation space of a Lie algebra, giving the symmetries of the Standard Model. In this paper, this representation is made explicit, obtaining the raising operators associated with the Lie algebra of $SU(5)$, one of the earliest grand unified theories. Because the braids form a group, the action of these operators are braids themselves, ...
Approaches for Tensile Testing of Braided Composites
Roberts, Gary D.; Salem, Jonathan A.; Bail, Justin L.; Kohlman, Lee W.; Binienda, Wieslaw K.; Martin, Richard E.
2011-01-01
For angleply composites, lamina tension and compression strengths are commonly determined by applying classical lamination theory to test data obtained from testing of angleply composite specimens. For textile composites such as 2D triaxial braids, analysis is more complex and standard test methods do not always yield reliable strength measurements. This paper describes recent research focused on development of more reliable tensile test methods for braided composites and presents preliminary data for various approaches. The materials investigated in this work have 0deg+/-60 2D triaxial braid architecture with nearly equal fiber volume fraction in each of the three fiber directions. Flat composite panels are fabricated by resin transfer molding (RTM) using six layers of the braided preform aligned along the 0deg fiber direction. Various epoxy resins are used as matrix materials. Single layer panels are also fabricated in order to examine local variations in deformation related to the braid architecture. Specimens are cut from these panels in the shape of standard straight-sided coupons, an alternative bowtie geometry, and an alternative notched geometry. Axial tensile properties are measured using specimens loaded along the 0deg fiber direction. Transverse tensile properties are measured using specimens loaded perpendicular to the 0deg fibers. Composite tubes are also fabricated by RTM. These tubes are tested by internal pressurization using a soft rubbery material sealed between the inside diameter of the tube and the load fixtures. The ends of the tube are unconstrained, so the primary load is in the hoop direction. Tubes are fabricated with the 0deg fibers aligned along the tube axis by overbraiding the preform on a mandrel. Since the loading is in the hoop direction, testing of the overbraided tube provides a measure of transverse tensile strength. Previous work has indicated that straight-sided coupons yield a transverse tensile strength that is much lower
The braidings of mapping class groups and loop spaces
Song, Yongjin
2000-01-01
The disjoint union of mapping class groups forms a braided monoidal category. We give an explicit expression of braidings in terms of both their actions on the fundamental group of the surface and the standard Dehn twists. This braided monoidal category gives rise to a double loop space. We prove that the action of little 2-cube operad does not extend to the action of little 3-cube operad by showing that the Browder operation induced by 2-cube operad action is nontrivial. A rather simple expr...
Braiding surface links which are coverings over the standard torus
NAKAMURA, Inasa
2009-01-01
We consider a surface link in the 4-space which can be presented by a simple branched covering over the standard torus, which we call a torus-covering link. Torus-covering links include spun $T^2$-knots and turned spun $T^2$-knots. In this paper we braid a torus-covering link over the standard 2-sphere. This gives an upper estimate of the braid index of a torus-covering link. In particular we show that the turned spun $T^2$-knot of the torus $(2,\\,p)$-knot has the braid index four.
Quilts central extensions, braid actions, and finite groups
2000-01-01
Quilts are 2-complexes used to analyze actions and subgroups of the 3-string braid group and similar groups. This monograph establishes the fundamentals of quilts and discusses connections with central extensions, braid actions, and finite groups. Most results have not previously appeared in a widely available form, and many results appear in print for the first time. This monograph is accessible to graduate students, as a substantial amount of background material is included. The methods and results may be relevant to researchers interested in infinite groups, moonshine, central extensions, triangle groups, dessins d'enfants, and monodromy actions of braid groups.
Core reilforced braided composite armour as a substitute to steel in concrete reinforcement
Fangueiro, Raúl; Sousa, Guilherme José Miranda de; Araújo, Mário Duarte de; Pereira, C. Gonilho; Jalali, Said
2006-01-01
This paper presents the work that is being done at the University of Minho concerning the development of brainded rods concrete reinforcement. Several samples of core reinforced braided fabrics have been produced varying the type of braided fabric (core reinforced and hybrid), the linear density of the core reinforcing yarns and the type of braiding structure (with or without ribs). The tensile properties of braided fabrics has also been analysed. Core reinforced braided composites rods were ...
Plane strain deformation of a multi-layered poroelastic half-space by surface loads
Indian Academy of Sciences (India)
Sarva Jit Singh; Sunita Rani
2006-12-01
The Biot linearized quasi-static theory of ﬂuid-inﬁltrated porous materials is used to formulate the problem of the two-dimensional plane strain deformation of a multi-layered poroelastic half-space by surface loads. The Fourier–Laplace transforms of the stresses, displacements, pore pressure and ﬂuid ﬂux in each homogeneous layer of the multi-layered half-space are expressed in terms of six arbitrary constants. Generalized Thomson–Haskell matrix method is used to obtain the deformation ﬁeld. Simpliﬁed explicit expressions for the elements of the 6 × 6 propagator matrix for the poroelastic medium are obtained. As an example of the possible applications of the analytical formulation developed, formal solution is given for normal strip loading, normal line loading and shear line loading.
Numerical simulation of core convection by a multi-layer semi-implicit spherical spectral method
Cai, Tao; Chan, Kwing L.; Deng, Licai
2011-10-01
A semi-implicit multi-layer spherical spectral method for simulating stellar core convection is described. The fully compressible three-dimensional hydrodynamic equations with rotation and energy generation are solved. Prognostic variables are expressed as finite sums of spherical harmonics in the horizontal directions and handled by the finite difference method in the radial direction. The stratified approximation is used to simplify the nonlinearity to quadratic. A multi-layer scheme is employed to overcome the time step problem arising from shrinking grid sizes in the physical space near the center of the star. Despite of the different spectral truncations in different layers, round-off conservation of the total mass and total angular momentum of the whole domain can be maintained, and were confirmed numerically. The code is parallelized; with 12 processors the speedup factor is about 9. The solutions of model core convection with and without rotation are discussed.
Proposal of a multi-layer network architecture for OBS/GMPLS network interworking
Guo, Hongxiang; Tsuritani, Takehiro; Yin, Yawei; Otani, Tomohiro; Wu, Jian
2007-11-01
In order to enable the existing optical circuit switching (OCS) network to support both wavelength and subwavelength granularities, this paper proposes overlay-based multi-layer network architecture for interworking the generalized multi-protocol label switching (GMPLS) controlled OCS network with optical burst switching (OBS) networks. A dedicated GMPLS border controller with necessary GMPLS extensions, including group label switching path (LSP) provisioning, node capability advertisement, and standard wavelength label as well as wavelength availability advertisement, is introduced in this multi-layer network to enable a simple but flexible interworking operation. The feasibility of this proposal is experimentally confirmed by demonstrating an OBS/GMPLS testbed, in which the extended node capability advertisement and group LSP functions successfully enabled the burst header packet (BHP) and data burst (DB) to transmit over a GMPLS-controlled transparent OCS network.
Incorporation of multi-layer option into QAD-CGGP code
International Nuclear Information System (INIS)
In order to improve the results of the QAD-CGGP gamma dose rate calculation we have incorporated multi-layer (two-layer) shield option and a new buildup factor formula, published recently, into the code. Modified QAD has been tested by comparison to the published results. The improved version of the code has been used to calculate gamma dose rate of a planar source and a two-layer shield and the results have been compared with the SAS4 (Monte Carlo method). Also, the improved version of the code has been used to calculate dose rate of the RADLOK-55 low and intermediate waste drum placed inside the NPP Krsko transport (lead-iron) shield. The results of the calculation were compared with the standard QAD-CGGP results. Incorporation of the two-layer (multi-layer) option into QAD-CGGP point-kernel code seems to be justified, resulting in higher accuracy.(author)
PRESSURE-IMPULSE DIAGRAM OF MULTI-LAYERED ALUMINUM FOAM PANELS UNDER BLAST PRESSURE
Directory of Open Access Journals (Sweden)
CHANG-SU SHIM
2013-06-01
Full Text Available Anti-terror engineering has increasing demand in construction industry, but basis of design (BOD is normally not clear for designers. Hardening of structures has limitations when design loads are not defined. Sacrificial foam claddings are one of the most efficient methods to protect blast pressure. Aluminum foam can have designed yield strength according to relative density and mitigate the blast pressure below a target transmitted pressure. In this paper, multi-layered aluminum foam panels were proposed to enhance the pressure mitigation by increasing effective range of blast pressure. Through explicit finite element analyses, the performance of blast pressure mitigation by the multi-layered foams was evaluated. Pressure-impulse diagrams for the foam panels were developed from extensive analyses. Combination of low and high strength foams showed better applicability in wider range of blast pressure.
High temperature and current density induced degradation of multi-layer graphene
Energy Technology Data Exchange (ETDEWEB)
Wang, Baoming; Haque, M. A., E-mail: mah37@psu.edu [Mechanical and Nuclear Engineering, The Pennsylvania State University, 314, Leonhard Building, University Park, Pennsylvania 16802 (United States); Mag-isa, Alexander E.; Kim, Jae-Hyun [Korea Institute of Machinery and Materials, 156 Gajungbuk-ro, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Lee, Hak-Joo [Korea Institute of Machinery and Materials, 156 Gajungbuk-ro, Yuseong-gu, Daejeon 305-343 (Korea, Republic of); Center for Advanced Meta-Materials (CAMM), 156 Gajungbuk-ro, Yuseong-gu, Daejeon 305-343 (Korea, Republic of)
2015-10-19
We present evidence of moderate current density, when accompanied with high temperature, promoting migration of foreign atoms on the surface of multi-layer graphene. Our in situ transmission electron microscope experiments show migration of silicon atoms at temperatures above 800 °C and current density around 4.2 × 10{sup 7} A/cm{sup 2}. Originating from the micro-machined silicon structures that clamp the freestanding specimen, the atoms are observed to react with the carbon atoms in the multi-layer graphene to produce silicon carbide at temperatures of 900–1000 °C. In the absence of electrical current, there is no migration of silicon and only pyrolysis of polymeric residue is observed.
New multi layer data correlation algorithm for multi passive sensor location system
Institute of Scientific and Technical Information of China (English)
Zhou Li; Li Lingyun; He You
2007-01-01
Under the scenario of dense targets in clutter, a multi-layer optimal data correlation algorithm is proposed. This algorithm eliminates a large number of false location points from the assignment process by rough correlations before we calculate the correlation cost, so it avoids the operations for the target state estimate and the calculation of the correlation cost for the false correlation sets. In the meantime, with the elimination of these points in the rough correlation, the disturbance from the false correlations in the assignment process is decreased, so the data correlation accuracy is improved correspondingly. Complexity analyses of the new multi-layer optimal algorithm and the traditional optimal assignment algorithm are given. Simulation results show that the new algorithm is feasible and effective.
Institute of Scientific and Technical Information of China (English)
WANG Xin-yun; WU You-sheng; XIA Ju-chen; HU Guo-an
2005-01-01
The aluminum alloy parts used in airbag of car were studied with flow control forming(FCF) method,which was a good way to low forming force and better mechanical properties. The key technology of FCF was the design of control chamber to divide metal flow. So, the design method of FCF was analyzed and two type of control chamber were put forward. According to divisional principle, calculation model of forming force and approximate formula were given. Then forming process of aluminum alloy multi-layer cylinder parts was simulated. The effect of friction factor, die radius and punch velocity on metal flow and forming force was obtained. Finally, the experiment was preformed under the direction of theory and finite element(FE) simulation results. And the qualified parts were manufactured. The simulation data and experimental results show that the forming sequence of inner wall and outer wall, and then the force step, can be controlled by adjusting the process parameters. And the FCF technology proposed has very important application value in precision forging.
A Mixture Model for Robust Point Matching under Multi-Layer Motion
Jiayi Ma; Jun De Chen; Delie Ming; Jinwen Tian
2014-01-01
This paper proposes an efficient mixture model for establishing robust point correspondences between two sets of points under multi-layer motion. Our algorithm starts by creating a set of putative correspondences which can contain a number of false correspondences, or outliers, in addition to the true correspondences (inliers). Next we solve for correspondence by interpolating a set of spatial transformations on the putative correspondence set based on a mixture model, which involves estimati...
AN EXACT ANALYSIS OF FORCED THICKNESS-TWIST VIBRATIONS OF MULTI-LAYERED PIEZOELECTRIC PLATES
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
This paper deals with the thickness-twist vibration of a multi-layered rectangular piezoelectric plate of crystals of 6 mm symmetry or polarized ceramics. An exact solution is obtained from the three-dimensional equations of linear piezoelectricity. The solution is useful to the understanding and design of composite piezoelectric devices. A piezoelectric resonator, a piezoelectric transformer, and a piezoelectric generator are analyzed as examples.
Multi-layer Ti-based Coating Obtained by Arc PVD Method
Pavlov, Konstantin; Gorchakov, Konstantin; Gorchakova, Svetlana; Salojoki, Kari; Barchenko, Vladimir; Sokolov, Aleksandr
2013-01-01
We report the obtaining and primary studies of ~ 250microns thick multi-layer Ti-based protective coating deposited at high cooling rate from substance generated by cathode arc discharge in vacuum. High adhesion to steel substrate was attained through prior Arc plasma generator cleaning and successive Ion Bombardment method. All three arc-generated fractions including mainly droplet, vapour and ions have been utilised to form the coating. Obtained coating features pore-free, least defects and...
A multi-layer model for turbulent kinetic energy in pipe flows
Chen, Xi; Hussain, Fazle; She, Zhen-Su
2011-01-01
A multi-layer model of an energy length function is developed by employing recent results of the authors. The theory predicts the complete, mean streamwise turbulent kinetic-energy profile (MKP), in good agreement with empirical data for a wide range of Reynolds numbers (Re). In particular, a critical $Re_\\tau$ is predicted, beyond which a scaling anomaly appears and MKP develops a second peak.
Rodriguez Florez, Sergio Alberto; Fremont, Vincent; Bonnifait, Philippe
2008-01-01
In this paper, we present an extensive study about the influence and the behavior of the intrinsic camera calibration imprecisions and their propagation into the extrinsic calibration between a camera and a multi-layer lidar. Usually, the extrinsic calibration process involves the pose estimation of a reference object in the Cartesian frame of each sensor. From this fact, it is necessary to know the camera intrinsic parameters for estimating the position of an object on an image. Therefore, t...
Kyoung Hwan Kim; MinHo Yang; Kyeong Min Cho; Young-Si Jun; Sang Bok Lee; Hee-Tae Jung
2013-01-01
We present a simple and up-scalable method to produce highly repaired graphene oxide with a large surface area, by introducing spherical multi-layered graphene balls with empty interiors. These graphene balls are prepared via chemical vapor deposition (CVD) of Ni particles on the surface of the graphene oxides (GO). Transmission electron microscopy and Raman spectroscopy results reveal that defects in the GO surfaces are well repaired during the CVD process, with the help of nickel nanopartic...
Infinite elements for soil-structure interaction analysis in multi-layered halfspaces
Energy Technology Data Exchange (ETDEWEB)
Yun, Chung Bang; Kim, Jae Min [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of); Yang, Shin Chu [Korea High Speed Rail Construction Authority, Seoul (Korea, Republic of)
1994-07-01
This paper presents the theoretical aspects of a computer code (KIESSI) for soil-structure interaction analysis in a multi-layered halfspace using infinite elements. The shape functions of the infinite elements are derived from approximate expressions of the analytical solutions. Three different infinite elements are developed. They are the horizontal, the vertical and the comer infinite elements (HIE, VIE and CIE). Numerical example analyses are presented for demonstrating the effectiveness of the proposed infinite elements.
Numerical modelling of crack shielding and deflection in a multi-layered material system
Joyce, M R; Reed, P.A.S.; Syngellakis, S.
2003-01-01
Finite element analysis has been used to investigate the fatigue behaviour observed in testing a layered structure (representative of an automotive journal bearing). The aim of the analysis was to explain the deflection or bifurcation observed as a fatigue crack propagates through the multi-layered structure of a bearing. A fracture mechanics approach was adopted using detailed evaluations of the J-integral to assess and monitor both crack tip driving force and directional propensity with cra...
Siamese Multi-layer Perceptrons for Dimensionality Reduction and Face Identification
Zheng, Lilei; Duffner, Stefan; Idrissi, Khalid; Garcia, Christophe; Baskurt, Atilla
2015-01-01
This paper presents a framework using siamese Multi-layer Percep-trons (MLP) for supervised dimensionality reduction and face identification. Compared with the classical MLP that trains on fully labeled data, the siamese MLP learns on side information only, i.e., how similar of data examples are to each other. In this study, we compare it with the classical MLP on the problem of face identification. Experimental results on the Extended Yale B database demonstrate that the siamese MLP training...
Directory of Open Access Journals (Sweden)
Zheng-gang Xiao
2014-06-01
Full Text Available Both heating and solvent-spray methods are used to consolidate the standard grains of double-base oblate sphere propellants plasticized with triethyleneglycol dinitrate (TEGDN (TEGDN propellants to high density propellants. The obtained consolidated propellants are deterred and coated with the slow burning multi-layer coating. The maximum compaction density of deterred and coated consolidated propellants can reach up to 1.39 g/cm3. Their mechanic, deconsolidation and combustion performances are tested by the materials test machine, interrupted burning set-up and closed vessel, respectively. The static compression strength of consolidated propellants deterred by multi-layer coating increases significantly to 18 MPa, indicating that they can be applied in most circumstances of charge service. And the samples are easy to deconsolidate in the interrupted burning test. Furthermore, the closed bomb burning curves of the samples indicate a two-stage combustion phenomenon under the condition of certain thickness of coated multi-layers. After the outer deterred multi-layer coating of consolidated samples is finished burning, the inner consolidated propellants continue to burn and breakup into aggregates and grains. The high burning progressivity can be carefully obtained by the smart control of deconsolidation process and duration of consolidated propellants. The preliminary results of consolidated propellants show that a rapid deconsolidation process at higher deconsolidation pressure is presented in the dynamic vivacity curves of closed bomb test. Higher density and higher macro progressivity of consolidated propellants can be obtained by the techniques in this paper.
Carbon nano-onions (multi-layer fullerenes): chemistry and applications
Juergen Bartelmess; Silvia Giordani
2014-01-01
This review focuses on the development of multi-layer fullerenes, known as carbon nano-onions (CNOs). First, it briefly summarizes the most important synthetic pathways for their preparation and their properties and it gives the reader an update over new developments in the recent years. This is followed by a discussion of the published synthetic procedures for CNO functionalization, which are of major importance when elucidating future applications and addressing drawbacks for possible appli...
Matrix solution to longitudinal impedance of multi-layer circular structures
Energy Technology Data Exchange (ETDEWEB)
Hahn,H.
2008-10-01
A matrix method in which radial wave propagation is treated in analogy to longitudinal transmission lines is presented and applied to finding the longitudinal coupling impedance of axially symmetric multi-layer beam tubes. The method is demonstrated in the case of a Higher Order Mode ferrite absorber with an inserted coated ceramic beam tube. The screening of the ferrite damping properties by the dielectric beam tube is discussed.
Zheng-gang Xiao; San-jiu Ying; Fu-ming Xu
2014-01-01
Both heating and solvent-spray methods are used to consolidate the standard grains of double-base oblate sphere propellants plasticized with triethyleneglycol dinitrate (TEGDN) (TEGDN propellants) to high density propellants. The obtained consolidated propellants are deterred and coated with the slow burning multi-layer coating. The maximum compaction density of deterred and coated consolidated propellants can reach up to 1.39 g/cm3. Their mechanic, deconsolidation and combustion performances...
Fatigue crack monitoring in multi-layered aircraft structures using guided ultrasonic waves
Koston, E.
2010-01-01
The detection of fatigue cracks at fasteners in the sub layers of multi-layered aircraft structures can be problematic using conventional nondestructive testing methods. In this thesis the sensitivity of low frequency guided ultrasonic waves to detect these defects is studied. Guided ultrasonic waves typically have energy distributed through the thickness of such structures and allow for defect detection in all sub-layers, but have wavelengths larger than commonly used in bulk wave ...
International Nuclear Information System (INIS)
In this paper, the OTTANNO version of four -quadrant CMOS analog multiplier circuit for artificial neural networks multi layer perception operation will be proposed. The proposed multiplier can be divided into two or three parts, which will be in the input, synapse and neuron. The percentage of silicon area saving is 95% with respect to that multiplier presented in (Chible,1997). A comparison between OTANNO and OTANPS is also presented. (author)
Highly Accurate Multi-layer Perceptron Neural Network for Air Data System
H. S. Krishna
2009-01-01
The error backpropagation multi-layer perceptron algorithm is revisited. This algorithm is used to train and validate two models of three-layer neural networks that can be used to calibrate a 5-hole pressure probe. This paper addresses Occam's Razor problem as it describes the adhoc training methodology applied to improve accuracy and sensitivity. The trained outputs from 5-4-3 feed-forward network architecture with jump connection are comparable to second decimal digit (~0.05) accuracy, hith...
Multi-particle modelling for the prediction of delamination in multi-layered materials
CARON, JF; DIAZ DIAZ, A; CARREIRA, RP; CHABOT, A; EHRLACHER, A
2005-01-01
To approach the three-dimensional stress state in multi-layered composites, a laminate theory which considers a kinematic field per layer (particle) is used. Thus, interlaminar stresses are naturally introduced to carry out the equilibrium conditions of the plies. These stresses have a physical meaning and represent the exact out-of-plane 3D stresses calculated at the interface between two layers. These simplified models are able to provide finite interfacial stresses, even at the free edge o...
MUSIC imaging method for low-high frequency inspection of composite multi-layers
Rodeghiero, Giacomo; Ding, Ping-Ping; Zhong, Yu; Lambert, Marc; Lesselier, Dominique
2014-01-01
International audience Non-destructive Testing-Evaluation (NdT-E) of damaged multi-layer structures like fiber-made composite materials involved in aeronautic and automotive industries is a topic of great interest to solve problems of viability and security. From eddy currents to test graphite-based materials to microwaves and beyond to test glass-based composite structures, one aims to obtain images of the possibly damaged parts with robust, fast inversion algorithms. In this contribution...
Low-high frequency inspection of composite multi-layers and MUSIC-type electromagnetic imaging
Rodeghiero, Giacomo; Ding, Ping-Ping; Zhong, Yu; Lambert, Marc; Lesselier, Dominique
2014-01-01
International audience Non Destructive Testing-Evaluation (NdT-E) of complex multi-layer composite panels for problems of quality, viability, safety and availability of complex systems involving manufactured parts (in aeronautics and in automotive industry, as a good example) is becoming an interesting and challenging task nowadays. From eddy-currents to microwaves, there is the need to make available modeling and imaging procedures that will be robust, fast, accurate and useful to potenti...
Reference Architecture for Multi-Layer Software Defined Optical Data Center Networks
Casimer DeCusatis
2015-01-01
As cloud computing data centers grow larger and networking devices proliferate; many complex issues arise in the network management architecture. We propose a framework for multi-layer; multi-vendor optical network management using open standards-based software defined networking (SDN). Experimental results are demonstrated in a test bed consisting of three data centers interconnected by a 125 km metropolitan area network; running OpenStack with KVM and VMW are components. Use cases include i...
Unified Multi-Layer among Software Defined Multi-Domain Optical Networks (Invited)
Hui Yang; Yadi Cui; Jie Zhang
2015-01-01
The software defined networking (SDN) enabled by OpenFlow protocol has gained popularity which can enable the network to be programmable and accommodate both fixed and flexible bandwidth services. In this paper, we present a unified multi-layer (UML) architecture with multiple controllers and a dynamic orchestra plane (DOP) for software defined multi-domain optical networks. The proposed architecture can shield the differences among various optical devices from multi-vendors and the details o...
Evaluation of Multi Layers Web-based GIS Approach in Retrieving Tourist Related Information
Rosilawati Zainol; Zainab Abu Bakar
2014-01-01
Geo-based information is getting greater importance among tourists. However, retrieving this information on the web depends heavily on the methods of dissemination. Therefore, this study intends to evaluate methods used in disseminating tourist related geo-based information on the web using partial match query, firstly, in default system which is a single layer approach and secondly, using multi layer web-based Geographic Information System (GIS) approaches. Shah Alam tourist related data are...
Winner, Taryn L; Lanzarotta, Adam; Sommer, André J
2016-06-01
An effective method for detecting and characterizing counterfeit finished dosage forms and packaging materials is described in this study. Using attenuated total internal reflection Fourier transform infrared spectroscopic imaging, suspect tablet coating and core formulations as well as multi-layered foil safety seals, bottle labels, and cigarette tear tapes were analyzed and compared directly with those of a stored authentic product. The approach was effective for obtaining molecular information from structures as small as 6 μm. PMID:27068491
He, Xin
2012-01-01
This dissertation addresses cooperative communications and proposes multi-layer solu- tions for wireless local area networks, focusing on cooperative MAC design. The coop- erative MAC design starts from CSMA/CA based wireless networks. Three key issues of cooperation from the MAC layer are dealt with: i.e., when to cooperate (opportunistic cooperation), whom to cooperate with (relay selection), and how to protect cooperative transmissions (message procedure design). In addition...
Multi-layer Architecture For Storing Visual Data Based on WCF and Microsoft SQL Server Database
Grycuk, Rafal; Gabryel, Marcin; Scherer, Rafal; Voloshynovskiy, Sviatoslav
2015-01-01
In this paper we present a novel architecture for storing visual data. Effective storing, browsing and searching collections of images is one of the most important challenges of computer science. The design of architecture for storing such data requires a set of tools and frameworks such as SQL database management systems and service-oriented frameworks. The proposed solution is based on a multi-layer architecture, which allows to replace any component without recompilation of other component...
Femtosecond laser induced periodic surface structures on multi-layer graphene
Energy Technology Data Exchange (ETDEWEB)
Beltaos, Angela, E-mail: abeltaos@ualberta.ca; Kovačević, Aleksander G.; Matković, Aleksandar; Ralević, Uroš; Savić-Šević, Svetlana; Jovanović, Djordje; Jelenković, Branislav M.; Gajić, Radoš [Institute of Physics, University of Belgrade, Pregrevica 118, 11080 Belgrade (Serbia)
2014-11-28
In this work, we present an observation of laser induced periodic surface structures (LIPSS) on graphene. LIPSS on other materials have been observed for nearly 50 years, but until now, not on graphene. Our findings for LIPSS on multi-layer graphene were consistent with previous reports of LIPSS on other materials, thus classifying them as high spatial frequency LIPSS. LIPSS on multi-layer graphene were generated in an air environment by a linearly polarized femtosecond laser with excitation wavelength λ of 840 nm, pulse duration τ of ∼150 fs, and a fluence F of ∼4.3–4.4 mJ/cm{sup 2}. The observed LIPSS were perpendicular to the laser polarization and had dimensions of width w of ∼30–40 nm and length l of ∼0.5–1.5 μm, and spatial periods Λ of ∼70–100 nm (∼λ/8–λ/12), amongst the smallest of spatial periods reported for LIPSS on other materials. The spatial period and width of the LIPSS were shown to decrease for an increased number of laser shots. The experimental results support the leading theory behind high spatial frequency LIPSS formation, implying the involvement of surface plasmon polaritons. This work demonstrates a new way to pattern multi-layer graphene in a controllable manner, promising for a variety of emerging graphene/LIPSS applications.
Modeling of Multi-Layered Protection Systems for Chloride Penetration in Concrete Bridge Decks
Harajli, Ali A.
Modeling of Multi-Layered Protection Systems for Chloride Penetration in Concrete Bridge Decks. This paper covers the development of a new methodology for predicting the chloride concentration and corrosion initiation times for a multi-layer protection overlay system. The first topic will be presenting an innovative method to predict the chloride concentrations using different diffusion coefficients for each protective layer. The new method covers the cases where the applied surface chloride concentrations are either a constant or linear functions with time. The second topic will implement the results from field data about the chloride variations due to the presence of applied topical layers for comparison with the theoretical models. This section will also apply damage factors that are time-dependent to simulate external factors such as traffic loading or vibrations. The third topic will investigate the sensitivity of the single and multi-layer systems due to diffusivity parameter changes. The fourth topic will analyze the random variation of the diffusivity values to predict the mean and standard deviation of chloride concentrations. The diffusivity values are selected from published values by NIST and are based on certain water cement (w/c) ratios.
Chu, H K; Huan, Z; Mills, J K; Yang, J; Sun, D
2015-02-01
Cell manipulation is imperative to the areas of cellular biology and tissue engineering, providing them a useful tool for patterning cells into cellular patterns for different analyses and applications. This paper presents a novel approach to perform three-dimensional (3D) cell manipulation and patterning with a multi-layer engineered scaffold. This scaffold structure employed dielectrophoresis as the non-contact mechanism to manipulate cells in the 3D domain. Through establishing electric fields via this multi-layer structure, the cells in the medium became polarized and were attracted towards the interior part of the structure, forming 3D cellular patterns. Experiments were conducted to evaluate the manipulation and the patterning processes with the proposed structure. Results show that with the presence of a voltage input, this multi-layer structure was capable of manipulating different types of biological cells examined through dielectrophoresis, enabling automatic cell patterning in the time-scale of minutes. The effects of the voltage input on the resultant cellular pattern were examined and discussed. Viability test was performed after the patterning operation and the results confirmed that majority of the cells remained viable. After 7 days of culture, 3D cellular patterns were observed through SEM. The results suggest that this scaffold and its automated dielectrophoresis-based patterning mechanism can be used to construct artificial tissues for various tissue engineering applications. PMID:25501324
International Nuclear Information System (INIS)
We investigate the effect of coupling (intensity and nature), applied field, and anisotropy on the spin dynamics of a multi-layer system composed of a hard magnetic layer coupled to a soft magnetic layer through a nonmagnetic spacer. The soft layer is modeled as a stack of several atomic planes while the hard layer, of a different material, is either considered as a pinned macroscopic magnetic moment or again as a stack of atomic planes. We compute the magnetization profile and hysteresis loop of the whole multi-layer system by solving the Landau–Lifshitz equations for the net magnetic moment of each (atomic) plane. We study the competition between the intra-layer anisotropy and exchange interaction, applied magnetic field, and the interface exchange, dipolar or Dzyalozhinski–Moriya interaction. Compared with the exchange coupling, the latter two couplings present peculiar features in the magnetization profile and hysteresis loop that may help identify the nature of the interface coupling in multi-layer magnetic systems. (paper)
Development of planar CT system for multi-layer PCB inspection
International Nuclear Information System (INIS)
X-ray defect inspection apparatus can be used in the production line to inspect the PCB. However, a simple X-ray radiography cannot discriminate defects from the multi-layer PCBs because the layers of them overlays the defects. To complement this issue, computed tomography (CT) technology is applied to the NDT system which can offer 3-dimensional information of object. However, CT requires hundreds of projection images to examine a single PCB, hence real-time inspection is nearly impossible. In this study, we develop a planar computed tomography (pCT) system appropriate for the multi-layer PCB inspection. For the image reconstruction of planar cross-section images, we use the digital tomosynthesis (DTS) concept in association with the limited angle scanning. and performance characterization of the pCT system for the PCB inspection. The 3-d Fourier characteristics and more quantitative performance, such as contrast, uniformity, depth resolution will be presented. The cross-sectional images of multi-layer PCBs will also be demonstrated
Femtosecond laser induced periodic surface structures on multi-layer graphene
International Nuclear Information System (INIS)
In this work, we present an observation of laser induced periodic surface structures (LIPSS) on graphene. LIPSS on other materials have been observed for nearly 50 years, but until now, not on graphene. Our findings for LIPSS on multi-layer graphene were consistent with previous reports of LIPSS on other materials, thus classifying them as high spatial frequency LIPSS. LIPSS on multi-layer graphene were generated in an air environment by a linearly polarized femtosecond laser with excitation wavelength λ of 840 nm, pulse duration τ of ∼150 fs, and a fluence F of ∼4.3–4.4 mJ/cm2. The observed LIPSS were perpendicular to the laser polarization and had dimensions of width w of ∼30–40 nm and length l of ∼0.5–1.5 μm, and spatial periods Λ of ∼70–100 nm (∼λ/8–λ/12), amongst the smallest of spatial periods reported for LIPSS on other materials. The spatial period and width of the LIPSS were shown to decrease for an increased number of laser shots. The experimental results support the leading theory behind high spatial frequency LIPSS formation, implying the involvement of surface plasmon polaritons. This work demonstrates a new way to pattern multi-layer graphene in a controllable manner, promising for a variety of emerging graphene/LIPSS applications
Experimental observation of multi-layer excitation structure in capacitively coupled SF6 plasmas
Liu, Yong-Xin; Gao, Fei; Song, Yuan-Hong; Li, Xue-Chun; Wang, You-Nian
2015-09-01
Electron excitation dynamics in capacitively coupled SF6 plasmas driven at 9 MHz ~ 16 MHz are studied by using phase resolved optical emission spectroscopy (PROES) of trace rare gas. Multi-layer excitation structure inside the bulk plasma of capacitive discharges operating in SF6 is experimentally observed for the first time. Experimental results show that with the decrease of the rf power and/or the increase of the pressure, the multi-layer excitation structure becomes noticeable while the gap between two adjacent layers is almost kept constant. By increasing the driving frequency with a constant electrode gap, however, the number of layers increases while the layer gap decreases. The layer structure disappears at the driving frequency larger than 16 MHz. The electrode gap is found to have a negligible effect on the gap between two adjacent excitation layers, nevertheless only the number of excitation layers is increased when enlarging the electrode gap. The multi-layer formation may be due to a large modulation of the F- negative-ion density throughout the bulk plasma, and is more pronounced at intermediate and low frequencies, since F- negative ions do not respond to the time-varying electric field at high frequencies (>16 MHz). This work was supported by the National Natural Science Foundation of China (NSFC) (Grant No. 11335004) and (Grant No.11405018), and the International Science & Technology Cooperation Program of China (Grant No. 2012DFG02150).
Simulation of Fragment Impact on Multi-Layer Targets Using Contact Method
Institute of Scientific and Technical Information of China (English)
XIN Xudong; CRAWFORD John E
2006-01-01
Cased explosives generate highly energetic fragments as their casing breaks up.Due to the complexity of casing fragment related behavior such as embedment,perforation and ricochet,it may be insufficient to use equivalent triangular pressure loading in fragment impact simulations.This simplified method may over-or under-predict the target response.Recently,a procedure using contact techniques has been proposed to overcome such difficulties.It has been shown that the new method has the inherent capability in modeling the multi-piece and multi-hit fragment impact problems in a more realistic way.To investigate the applicability of the proposed method to simulations involving multi-layer penetration,the selected problems of fragment impact on multi-layer targets are described in this paper.It is demonstrated that this method is capable of predicting the complicated multi-layer structural response caused by fragment impact and penetration.Modeling procedures and some technical issues are also discussed.
Institute of Scientific and Technical Information of China (English)
Yusong Pan; Qianqian Shen; Chengling Pan; Jing Wang
2013-01-01
Functional gradient materials provided us a new concept for artificial articular cartilage design with gradient component and gradient structure where one side of the material is high free water content thereby providing excellent lubrication function and the opposite side of the material is high hydroxyapatite content,thereby improving the bioactivity of the material and stimulating cell growth.The goal of the present study was to develop a multi-layered gradient HA/PVA gel biocomposites through layer-by-layer casting method combing with freeze/thaw cycle technology.The various influence factors on the compressive strength and modulus of the multi-layered gradient biocomposites were investigated.The results showed that the compressive mechanical characteristics of the biocomposites were similar to that of natural articular cartilage.Both the compressive strength and modulus of the multi-layered gradient HA/PVA gel biocomposites increased exponentially with the rise of compressive strain ratio.Both the compressive strength and average compressive modulus of the biocomposites improved with the rise of freeze/thaw cycle times and total concentration of HA particles in the biocomposites,but they showed decreasing tendency with the rise of HA concentration difference between adjacent layers.
International Nuclear Information System (INIS)
The purpose of this study is to investigate the antibacterial activity of multi-layer of polyethylenimine (PEI) and carrageenan (κ,ι, λ) for potential use as coating on biomaterial surface. The multi-layer of PEI/carrageenan was formed using the layer-by-layer assembly absorption technique and was monitored by atomic force microscopy (AFM) and bio molecular interaction analysis. All samples were prepared in phosphate buffer solution and applied to mica disk alternately. The micrographs showed the formation of bi-layer of polyethylenimine and carrageenan (κ, ι, λ) as observed in the change of height of the layer and surface morphology. The bimolecular binding of carrageenan with polyethylenimine was also investigated using a biosensor. The sensorgram showed that PEI interacted molecularly with carrageenan. Results were: 1,916.08 pg/nm2 for kappa type; 1,844.1 pg/nm2 for iota type and 6,074.24 pg/nm2 for lambda type. The multi-layer showed antibacterial activity against Enterobacter cloaceae, Staphylococcus aureus and Enterococcal strains (Enterococcus faecalis (EF) 29212 and 29505). (author)
Institute of Scientific and Technical Information of China (English)
LI Ming; WANG Ming; RONG Hua; LI Hong-Pu
2006-01-01
@@ An optical microelectromechanical-system (MEMS) pressure sensor based on multi-layer circular diaphragm is described and analysed by using the proposed novel analytical approach and the traditional transfer matrix method. The analytical expressions of the deflection of multi-layer diaphragm and absolute optical reflectance are derived respectively. The influence of residual stress on the deflection of diaphragm is also analysed. Simulation results given by the finite element method are consistent with the ones which are analysed by using the analytical approach. The analytical approach will be helpful to design and fabricate the optical MEMS pressure sensors with multi-layer diaphragm based on Fabry-Perot interferometry.
International Nuclear Information System (INIS)
Multi-layer films of hexafluoropropene - ethylene composite polymer were deposited with a jet-type plasma reactor on poly (ethylene terephthalate) films, which were used as base films, at atmospheric pressure. The multi-layer films were made up by decreasing the flow rate of ethylene gas gradually and increasing that of hexafluoropropene gas simultaneously during the plasma-polymerization. Those films showed low enough peel force, whose value was near that of a Teflon sheet used as a control. Moreover, the bond strength between the multi-layer film and the base film became stronger than that between a plasma-polymerized hexatluoropropene film and the base film. (author)
Mishra, Srinibash; Roy, Gour Gopal
2016-08-01
The effect of carbon-to-hematite molar ratio has been studied on the reduction efficiency of iron ore-coal composite pellet reduced at 1523 K (1250 °C) for 20 minutes in a laboratory scale multi-layer bed rotary hearth furnace (RHF). Reduced pellets have been characterized through weight loss measurement, estimation of porosity, shrinkage, qualitative and quantitative phase analysis by XRD. Performance parameters such as the degree of reduction, metallization, carbon efficiency, productivity, and compressive strength have been calculated to compare the process efficacy at different carbon levels in the pellets. Pellets with optimum carbon-to-hematite ratio (C/Fe2O3 molar ratio = 1.66) that is much below the stoichiometric carbon required for direct reduction of hematite yielded maximum reduction, better carbon utilization, and productivity for all three layers. Top layer exhibited maximum reduction at comparatively lower carbon level (C/Fe2O3 molar ratio 2.33). Correlation between degree of reduction and metallization indicated non-isothermal kinetics influenced by heat and mass transfer in multi-layer bed RHF. Compressive strength of the partially reduced pellet with optimum carbon content (C/Fe2O3 molar ratio = 1.66) showed that they could be potentially used as an alternate feed in a blast furnace or any other smelting reactor.
Mishra, Srinibash; Roy, Gour Gopal
2016-04-01
The effect of carbon-to-hematite molar ratio has been studied on the reduction efficiency of iron ore-coal composite pellet reduced at 1523 K (1250 °C) for 20 minutes in a laboratory scale multi-layer bed rotary hearth furnace (RHF). Reduced pellets have been characterized through weight loss measurement, estimation of porosity, shrinkage, qualitative and quantitative phase analysis by XRD. Performance parameters such as the degree of reduction, metallization, carbon efficiency, productivity, and compressive strength have been calculated to compare the process efficacy at different carbon levels in the pellets. Pellets with optimum carbon-to-hematite ratio (C/Fe2O3 molar ratio = 1.66) that is much below the stoichiometric carbon required for direct reduction of hematite yielded maximum reduction, better carbon utilization, and productivity for all three layers. Top layer exhibited maximum reduction at comparatively lower carbon level (C/Fe2O3 molar ratio 2.33). Correlation between degree of reduction and metallization indicated non-isothermal kinetics influenced by heat and mass transfer in multi-layer bed RHF. Compressive strength of the partially reduced pellet with optimum carbon content (C/Fe2O3 molar ratio = 1.66) showed that they could be potentially used as an alternate feed in a blast furnace or any other smelting reactor.
Failure analysis of woven and braided fabric reinforced composites
Naik, Rajiv A.
1994-01-01
A general purpose micromechanics analysis that discretely models the yarn architecture within the textile repeating unit cell was developed to predict overall, three dimensional, thermal and mechanical properties, damage initiation and progression, and strength. This analytical technique was implemented in a user-friendly, personal computer-based, menu-driven code called Textile Composite Analysis for Design (TEXCAD). TEXCAD was used to analyze plain weave and 2x2, 2-D triaxial braided composites. The calculated tension, compression, and shear strengths correlated well with available test data for both woven and braided composites. Parametric studies were performed on both woven and braided architectures to investigate the effects of parameters such as yarn size, yarn spacing, yarn crimp, braid angle, and overall fiber volume fraction on the strength properties of the textile composite.
Directory of Open Access Journals (Sweden)
Hüseyin Kuplay
2013-03-01
Full Text Available Introduction: Venous leg ulcer is a major health problem in terms of high prevalence and high cost for treatment. Multi-layer compression bandage systems for venous leg ulcers are supposed to be the gold standard for the treatment of venous ulcers. The aim of the current study is to investigate the effectiveness of multi-layer compression bandage systems for the treatment of venous leg ulcers.Patients and Methods: Nineteen consecutive patients diagnosed to have leg ulcers were evaluated and four patients were excluded from the study due to the peripheral arterial disease. Fifteen patients, enrolled in the study, were classified according to CEAP classification and belonged to the same class. Betaven® multi-layer compression bandage was applied to patients. Patients were followed-up in terms of wound healing and reduction in wound diameter.Results: Twelve male and three female patients underwent multi-layer bandage system. Mean age of patients was 38.2 ± 4.2 years. Ulcer size was measured planimetrically and baseline ulcer size was 4-10 cm². The location of ulcer was on medial malloelus in seven patients, lateral malleolus in three patients, anterior surface of the leg in four patients and lateral side of the leg in one patient. Patients had chronic venous insuuficiency for a mean of 5.1 ± 2.1 years. CEAP classifications were C6, Ep, As2,3-p18, Pr2,3, 18. Each bandage was changed five days after application along with wound care. Mean duration of treatment was 6 ± 2 weeks. Complete healing of the venous ulcers occurred in all patients except for one. This patient was referred to plastic surgery clinic for reconstruction.Conclusion: Multi-layer compression bandage system is an effective method of treatment for venous leg ulcers associated with chronic venous insufficiency by reducing venous return and increasing intertitial tissue pressure. This effect occurred in the shortrun as well as with a low cost and prevented loss of labor.
Braided Tensor Categories and Extensions of Vertex Operator Algebras
Huang, Yi-Zhi; Kirillov, Alexander; Lepowsky, James
2015-08-01
Let V be a vertex operator algebra satisfying suitable conditions such that in particular its module category has a natural vertex tensor category structure, and consequently, a natural braided tensor category structure. We prove that the notions of extension (i.e., enlargement) of V and of commutative associative algebra, with uniqueness of unit and with trivial twist, in the braided tensor category of V-modules are equivalent.
Multifunctional braided composite rods for civil engineering applications
Fangueiro, Raúl; Zdraveva, Emilijia; Pereira, Cristiana Gonilho; Lanceros-Méndez, S.; Jalali, Said; Araújo, Mário Duarte de
2010-01-01
This paper presents the development of a braided reinforced composite rod (BCR) able to both reinforce and monitor the stress state of concrete elements. Carbon fibers have been used as sensing and reinforcing material along with glass fiber. Various composites rods have been produced using an author patented technique based on a modified conventional braiding machine. The materials investigated were prepared with different carbon fiber content as follows: BCR2 (77% glass/23% c...
Self-Sustained Magnetic Braiding in Toroidal Plasmas
Itoh, K; Fukuyama, A.; Itoh, S.-I.; Yagi, M.; Azumi, M.
1994-01-01
Theory for the magnetic braiding in toroidal plasmas, which is caused by microscopic pressure-gradient-driven turbulence, is developed. When the pressure gradient exceeds a threshold, the self-sustaining of the magnetic braiding and enhanced anomalous transport occur. The balance between the nonlinear destabilization and nonlinear stabilization, which determines the stationary turbulence, is solved analytically for the case of interchange mode. The enhanced thermal conductivity and magneti...
Braids as a representation space of SU(5)
Cartin, Daniel
2015-06-01
The standard model of particle physics provides very accurate predictions of phenomena occurring at the sub-atomic level, but the reason for the choice of symmetry group and the large number of particles considered elementary is still unknown. Along the lines of previous preon models positing a substructure to explain these aspects, Bilson-Thompson showed how the first family of elementary particles is realized as the crossings of braids made of three strands, with charges resulting from twists of those strands with certain conditions; in this topological model, there are only two distinct neutrino states. Modeling the particles as braids implies these braids must be the representation space of a Lie algebra, giving the symmetries of the standard model. In this paper, this representation is made explicit, obtaining the raising operators associated with the Lie algebra of SU(5), one of the earliest grand unified theories. Because the braids form a group, the action of these operators are braids themselves, leading to their identification as gauge bosons. Possible choices for the other two families are also given. Although this realization of particles as braids is lacking a dynamical framework, it is very suggestive, especially when considered as a natural method of adding matter to loop quantum gravity.
Braids as a representation space of SU(5)
International Nuclear Information System (INIS)
The standard model of particle physics provides very accurate predictions of phenomena occurring at the sub-atomic level, but the reason for the choice of symmetry group and the large number of particles considered elementary is still unknown. Along the lines of previous preon models positing a substructure to explain these aspects, Bilson-Thompson showed how the first family of elementary particles is realized as the crossings of braids made of three strands, with charges resulting from twists of those strands with certain conditions; in this topological model, there are only two distinct neutrino states. Modeling the particles as braids implies these braids must be the representation space of a Lie algebra, giving the symmetries of the standard model. In this paper, this representation is made explicit, obtaining the raising operators associated with the Lie algebra of SU(5), one of the earliest grand unified theories. Because the braids form a group, the action of these operators are braids themselves, leading to their identification as gauge bosons. Possible choices for the other two families are also given. Although this realization of particles as braids is lacking a dynamical framework, it is very suggestive, especially when considered as a natural method of adding matter to loop quantum gravity
Mechanical properties of triaxially braided composites: Experimental and analytical results
Masters, John E.; Foye, Raymond L.; Pastore, Christopher M.; Gowayed, Yasser A.
1992-01-01
The unnotched tensile properties of 2-D triaxial braid reinforced composites from both an experimental and an analytical viewpoint are studied. The materials are graphite fibers in an epoxy matrix. Three different reinforcing fiber architectures were considered. Specimens were cut from resin transfer molded (RTM) composite panels made from each braid. There were considerable differences in the observed elastic constants from different size strain gage and extensometer reading. Larger strain gages gave more consistent results and correlated better with the extensometer reading. Experimental strains correlated reasonably well with analytical predictions in the longitudinal, 0 degrees, fiber direction but not in the transverse direction. Tensile strength results were not always predictable even in reinforcing directions. Minor changes in braid geometry led to disproportionate strength variations. The unit cell structure of the triaxial braid was discussed with the assistance of computer analysis of the microgeometry. Photomicrographs of braid geometry were used to improve upon the computer graphics representations of unit cells. These unit cells were used to predict the elastic moduli with various degrees of sophistication. The simple and the complex analyses were generally in agreement but none adequately matched the experimental results for all the braids.
Analysis of woven and braided fabric reinforced composites
Naik, Rajiv A.
1994-01-01
A general purpose micromechanics analysis that discretely models the yarn architecture within the textile repeating unit cell, was developed to predict overall, three dimensional, thermal and mechanical properties. This analytical technique was implemented in a user-friendly, personal computer-based, windows compatible code called Textile Composite Analysis for Design (TEXCAD). TEXCAD was used to analyze plain, 5-harness satin, and 8-harness satin weave composites along with 2-D braided and 2x2, 2-D triaxial braided composites. The calculated overall stiffnesses correlated well with available 3-D finite element results and test data for both the woven and the braided composites. Parametric studies were performed to investigate the effects of yarn size on the yarn crimp and the overall thermal and mechanical constants for plain weave composites. The effects of braid angle were investigated for the 2-D braided composites. Finally, the effects of fiber volume fraction on the yarn undulations and the thermal and mechanical properties of 2x2, 2-D triaxial braided composites were also investigated.
National Aeronautics and Space Administration — The main objective of the proposed work is to design and develop a multi-layer intelligent Loss-of-control Prevention System (LPS) for flight control applications....
LU, ZHENG; Yao, Hailin; Zhang, JingBo
2014-01-01
In this research work, a method to estimate the dynamic characteristics of a multilayered pavement with bituminous or concrete materials is proposed. A mechanical model is established to investigate the dynamic displacement and stress of the multi-layered pavement structure. Both the flexible and the rigid pavements, corresponding to bituminous materials and concrete materials, respectively, are studied. The theoretical solutions of the multi-layered pavement structure are deduced considering...
Directory of Open Access Journals (Sweden)
R. I. Еsman
2014-06-01
Full Text Available The paper gives a mathematical model and numerical solution of the problem on non-stationary heat conduction of multi-layer media with due account of phase transformations in phase boundary. In this case displacement of phase transformation front along section of multi-layer media is taken into account.The developed mathematical model is applied for calculation of temperature fields of isotropic and anisotropic media at various boundary conditions.
Kitaoka, Yoshio
2007-03-01
High-temperature superconductivity (HTSC) has not been fully understood yet despite 20 year's intensive research. In particular, a possible interplay between antiferromagnetism (AFM) and HTSC remains as a most interesting problem. It is believed that they all fit into a universal phase diagram which suggests a competition between AFM and HTSC. Recently, however, through the systematic Cu-NMR studies on the Hg-, Tl- and Cu-based five-layered HTSC, we propose a novel phase diagram [1-3], which differs from the generic phase diagram of the HTSC reported so far, for instance, such as LSCO. The multi-layered HTSC compounds include two types of CuO2 planes, an outer CuO2 plane (OP) in a pyramidal coordination and an inner CuO2 plane (IP) in a square one with no apical oxygen. Remarkable feature of the multi-layered HTSC is the presence of ideally flat CuO2 planes that are homogeneously doped, which is ensured by the narrowest NMR spectral width among the various HTSC compounds with very high quality to date. It should be noted that the nearly non-doped AFM in the IP and the IP* takes place, whereas inhomogeneous magnetic phases such as spin-glass phase or stripe phase are not observed at both the IP's and the OP's. Instead, the existence of the doped AFM metallic (AFMM) phase at the IP and the IP* is remarkable at the boundary between AFM insulating (AFMI) phase and SC. This differs from the case of LSCO where the disorder-driven magnetic phases exist between the AFMI phase in Nh 0.05. In an underlying phase diagram, the AFMM is extended to a higher hole density due to the flatness of CuO2 plane with no apical oxygen and the homogeneous distribution of carrier density. By contrast, the prototype phase diagrams reported thus far are under the inevitable disorder effect associated with the chemical substitution introduced into the CuO2 out-of-planes as corroborated by the observation of a disorder-driven transition from AFMM phase to AFMI phase found in theCu-based multi-layered
Production and crosslinking of multi-layer tubes (PE & metal) by E-beam
Zyball, Alfred
2000-03-01
Irradiation crosslinking of PE-tubes has been used for heating floors for about 25 years. Such tubes are also used today for drinking water supply. A further development has been the coating of such tubes with Ethylene-Vinyl-Alcohol-Copolymers (EVAL), in order to prevent oxygen diffusion into the water through the PE tube. For about 15 years composite tubes made of PE and aluminum have been available. These tubes are crosslinked with electron beams. The energy of the accelerated electrons must be adjusted for the particular tube configuration, so that the inner PE-layer will be crosslinked. This paper will concern itself with the manufacture and the crosslinking of composite tubes.
Directory of Open Access Journals (Sweden)
McVeigh Elliot R
2009-08-01
Full Text Available Abstract Background Catheter visualization and tracking remains a challenge in interventional MR. Active guidewires can be made conspicuous in "profile" along their whole shaft exploiting metallic core wire and hypotube components that are intrinsic to their mechanical performance. Polymer-based catheters, on the other hand, offer no conductive medium to carry radio frequency waves. We developed a new "active" catheter design for interventional MR with mechanical performance resembling braided X-ray devices. Our 75 cm long hybrid catheter shaft incorporates a wire lattice in a polymer matrix, and contains three distal loop coils in a flexible and torquable 7Fr device. We explored the impact of braid material designs on radiofrequency and mechanical performance. Results The incorporation of copper wire into in a superelastic nitinol braided loopless antenna allowed good visualization of the whole shaft (70 cm in vitro and in vivo in swine during real-time MR with 1.5 T scanner. Additional distal tip coils enhanced tip visibility. Increasing the copper:nitinol ratio in braiding configurations improved flexibility at the expense of torquability. We found a 16-wire braid of 1:1 copper:nitinol to have the optimum balance of mechanical (trackability, flexibility, torquability and antenna (signal attenuation properties. With this configuration, the temperature increase remained less than 2°C during real-time MR within 10 cm horizontal from the isocenter. The design was conspicuous in vitro and in vivo. Conclusion We have engineered a new loopless antenna configuration that imparts interventional MR catheters with satisfactory mechanical and imaging characteristics. This compact loopless antenna design can be generalized to visualize the whole shaft of any general-purpose polymer catheter to perform safe interventional procedures.
Topology and geometry of nematic braids
Energy Technology Data Exchange (ETDEWEB)
Čopar, Simon, E-mail: simon.copar@fmf.uni-lj.si
2014-05-01
Topological analysis of disclinations in nematic liquid crystals is an interesting and diverse topic that goes from strict mathematical theorems to applications in elaborate systems found in experiments and numerical simulations. The theory of nematic disclinations is shown from both the geometric and topological perspectives. Entangled disclination line networks are analyzed based on their shape and the behavior of their cross section. Methods of differential geometry are applied to derive topological results from reduced geometric information. For nematic braids, systems of −1/2 disclination loops, created by inclusion of homeotropic colloidal particles, a formalism of rewiring is constructed, allowing comparison and construction of an entire set of different conformations. The disclination lines are described as ribbons and a new topological invariant, the self-linking number, is introduced. The analysis is generalized from a constant −1/2 profile to general profile variations, while retaining the geometric treatment. The workings of presented topological statements are demonstrated on simple models of entangled nematic colloids, estimating the margins of theoretical assumptions made in the formal derivations, and reviewing the behavior of the disclinations not only under topological, but also under free-energy driven constraints.
Directory of Open Access Journals (Sweden)
Jean-Francois Castet
Full Text Available This article develops a novel approach and algorithmic tools for the modeling and survivability analysis of networks with heterogeneous nodes, and examines their application to space-based networks. Space-based networks (SBNs allow the sharing of spacecraft on-orbit resources, such as data storage, processing, and downlink. Each spacecraft in the network can have different subsystem composition and functionality, thus resulting in node heterogeneity. Most traditional survivability analyses of networks assume node homogeneity and as a result, are not suited for the analysis of SBNs. This work proposes that heterogeneous networks can be modeled as interdependent multi-layer networks, which enables their survivability analysis. The multi-layer aspect captures the breakdown of the network according to common functionalities across the different nodes, and it allows the emergence of homogeneous sub-networks, while the interdependency aspect constrains the network to capture the physical characteristics of each node. Definitions of primitives of failure propagation are devised. Formal characterization of interdependent multi-layer networks, as well as algorithmic tools for the analysis of failure propagation across the network are developed and illustrated with space applications. The SBN applications considered consist of several networked spacecraft that can tap into each other's Command and Data Handling subsystem, in case of failure of its own, including the Telemetry, Tracking and Command, the Control Processor, and the Data Handling sub-subsystems. Various design insights are derived and discussed, and the capability to perform trade-space analysis with the proposed approach for various network characteristics is indicated. The select results here shown quantify the incremental survivability gains (with respect to a particular class of threats of the SBN over the traditional monolith spacecraft. Failure of the connectivity between nodes is also
Cosmic radiation shielding properties of COLUMBUS and REMSIM multi-layer external shells
Durante, Marco; Manti, Lorenzo; Rusek, Adam; Belluco, Maurizio; Lobascio, Cesare
The European module COLUMBUS has been recently installed on the International Space Station. Future plans for exploration involve the use of inflatable modules, such as the REMSIM concept proposed in a previous ESA funded study. We studied the radiation shielding properties of COLUMBUS and REMSIM external shell using 1 GeV/n Feor H-ions accelerated at the NASA Space Radiation Laboratory at the Brookhaven National Laboratory (Long Island, NY, USA). COLUMBUS has a 22 mm rigid multi-layer shell with Al, Nextel and Kevlar, as materials of the double bumper for meteoroids and debris protection, MLI for thermal reasons and again Al as pressure shell. Inside the module, astronauts are further protected by secondary structures, including racks, a number of electronic devices and payload equipment. This internal equipment has been simulated using Al and Kevlar, bringing the total thickness to about 15 g/cm2. REMSIM consists of a thermal multi-layer (MLI), four Nextel layers used to provide shock of the impacting micro-meteoroids, a ballistic restraint multi-layer of Kevlar used to absorb debris cloud's kinetic energy, a Kevlar structural restraint to support pressure loads incurred from inflating the module. To contain air inside the module, REMSIM adopts three layers of airtight material separated by two layers of Kevlar (air bladder). A final layer of Nomex provide protection against punctures and fire. In the flight configuration there are also spacer elements (foam) needed to guarantee correct spacing between consecutive bumper layers. These spacers were not included in the tests, making the total thickness about 1.1 cm. The internal equipment in REMSIM was not been defined, but due to its application for exploration missions it was decided to exploit water, valuable resource used for drinking, washing and technical usage, as a radiation shielding. In this test, we have included about 8 cm of water. Measured dose attenuation shows that the Columbus module reduces the
International Nuclear Information System (INIS)
Highlights: • DC microgrid (PV array, storage, power grid connection, DC load) with multi-layer supervision control. • Power balancing following power flow optimization while providing interface for smart grid communication. • Optimization under constraints: storage capability, grid power limitations, grid time-of-use pricing. • Experimental validation of DC microgrid power flow optimization by multi-layer supervision control. • DC microgrid able to perform peak shaving, to avoid undesired injection, and to make full use of locally energy. - Abstract: Urban areas have great potential for photovoltaic (PV) generation, however, direct PV power injection has limitations for high level PV penetration. It induces additional regulations in grid power balancing because of lacking abilities of responding to grid issues such as reducing grid peak consumption or avoiding undesired injections. The smart grid implementation, which is designed to meet these requirements, is facilitated by microgrids development. This paper presents a DC microgrid (PV array, storage, power grid connection, DC load) with multi-layer supervision control which handles instantaneous power balancing following the power flow optimization while providing interface for smart grid communication. The optimization takes into account forecast of PV power production and load power demand, while satisfying constraints such as storage capability, grid power limitations, grid time-of-use pricing and grid peak hour. Optimization, whose efficiency is related to the prediction accuracy, is carried out by mixed integer linear programming. Experimental results show that the proposed microgrid structure is able to control the power flow at near optimum cost and ensures self-correcting capability. It can respond to issues of performing peak shaving, avoiding undesired injection, and making full use of locally produced energy with respect to rigid element constraints
Vortex dynamics in Hg-based multi- and super-multi-layered cuprates
International Nuclear Information System (INIS)
Hg-based multi- and super-multi-layered cuprates HgBa2Can-1CunOy (Hg:12(n-1)n) (n≥4) are composed of the charge reservoir layer (CRL) HgBa2Ox, and of CuO2 planes: outer planes (OP) with pyramidal oxygen coordination and inner planes (IP) with square oxygen coordination, with different charge distribution. This fact gives rise to very interesting phenomena, like coexistence of superconductivity (SC) in OPs with antiferromagnetism (AF) in IPs in Hg:1245. The dependence of Tc on the number n of CuO2 planes is also interesting: for n increasing from 4 to 5 and to 6, Tc decrease from 125 to 108 and then to about 103 K; further increase in n keeps Tc constant at about 103 K. In Hg:1245 we show that the AF ordering at TN of 60 K has no influence on vortex dynamics, and there is a quite robust c-axis supercurrent. Vortex melting lines of various samples showed that Hg-based multi-layered cuprates (n = 4, 5) behaves in the usual way (increasing n resulted in decrease of Josephson coupling (JC) and a less sharp melting line) and are well described by the usual anisotropic GL-based theory. Samples with n ≥ 6 have all the same melting line, suggesting that, in this case, the short-range JC becomes much less important than the long-range magnetic coupling (MC). However, since the JC between two pancakes in OPs of adjacent unit cells (pancakes separated by the thin CRL) is large, we suggest that the vortex matter in Hg-based super-multi-layered cuprates is composed of magnetically-coupled pancake-vortex-molecules
Detection of multi-layer and vertically-extended clouds using A-train sensors
Directory of Open Access Journals (Sweden)
J. Joiner
2009-10-01
Full Text Available The detection of multiple cloud layers using satellite observations is important for retrieval algorithms as well as climate applications. In this paper, we describe a relatively simple algorithm to detect multiple cloud layers and distinguish them from vertically-extended clouds. The algorithm can be applied to coincident passive sensors that derive both cloud-top pressure from the thermal infrared observations and an estimate of solar photon pathlength from UV, visible, or near-IR measurements. Here, we use data from the A-train afternoon constellation of satellites: cloud-top pressure, cloud optical thickness, and the multi-layer flag from the Aqua MODerate-resolution Imaging Spectroradiometer (MODIS and the optical centroid cloud pressure from the Aura Ozone Monitoring Instrument (OMI. The cloud classification algorithms applied with different passive sensor configurations compare well with each other as well as with data from the A-train CloudSat radar.
We compute monthly mean fractions of pixels containing multi-layer and vertically-extended clouds for January and July 2007 at the OMI spatial resolution (12 km×24 km at nadir and at the 5 km×5 km MODIS resolution for infrared cloud retrievals. There are seasonal variations in the spatial distribution of the different cloud types. The fraction of pixels containing distinct multi-layer cloud is a strong function of the pixel size. Globally averaged, these fractions are approximately 20% and 5% for OMI and MODIS, respectively. These fractions may be significantly higher or lower depending upon location. There is a much smaller resolution dependence for fractions of pixels containing vertically-extended clouds (~20% for OMI and slightly less for MODIS globally, suggesting larger spatial scales for these clouds. We also find significantly higher fractions of vertically-extended clouds over land as compared with ocean, particularly in the tropics and summer hemisphere.
Characterization of the morphology of co-extruded, thermoplastic/rubber multi-layer tapes
International Nuclear Information System (INIS)
Tapes with alternating semi-crystalline thermoplastic/rubber layers with thicknesses varying from 100 nm up to several μm were prepared by multi-layer co-extrusion. The variation in layer thickness was obtained by varying the thermoplastic/rubber feed ratio. A systematic study on the use of various microscopy techniques to visualize the morphology of the layered systems is presented. The relatively large length scales and the sample preparation make optical microscopy (OM) unsuitable to study the morphology of the multi-layer tapes. Although excellent contrast between the thermoplastic and rubber layers can be obtained, the usually applied, relatively large magnifications limit the use of transmission electron microscopy (TEM) and atomic force microscopy (AFM) to small sample areas. The large range of applicable magnifications makes scanning electron microscopy (SEM) the most suitable technique to study the morphology of the multi-layer tapes. The sample preparation for SEM with a secondary electron (SE) detector is often based on the removal of one of the components, which may induce changes in the morphology. SEM with a back-scattered electron (BSE) detector is a very convenient method to study the morphology over a wide range of length scales, where the contrast between the different layers can be enhanced by chemical staining. Finally, the nucleation behavior (homogeneous versus heterogeneous) of the semi-crystalline layers, as probed by differential scanning calorimetry (DSC), provides valuable information on the layered morphology. The use of relatively straightforward DSC measurements shows a clear advantage with respect to the discussed microscopy techniques, since no sample preparation is required and relatively large samples can be studied, which are more representative for the bulk.
Calibration and multi-layer inversion of multiple electromagnetic induction sensor data
von Hebel, Christian; van der Kruk, Jan; Mester, Achim; Altdorff, Daniel; Zimmermann, Egon; Endres, Anthony; Vereecken, Harry
2016-04-01
Multi-coil electromagnetic induction (EMI) sensors record simultaneously the apparent electrical conductivity (ECa) distribution of different integrated depths that can principally be used to invert for hydrologically relevant subsurface structures. However, EMI sensors induce not only magnetic fields in the subsurface but external conditions, e.g. the field setup, generate additional fields that shift the recorded ECa values. To obtain quantitative multi-coil EMI-ECa that make a multi-layer inversion possible, a post-calibration is required. Calibration for each coil configuration is performed using linear regressions between measured and predicted ECa that were obtained by inserting the electrical conductivities of inverted electrical resistivity tomography (ERT) data into a Maxwell-based EMI forward model. We measured 43 of these calibration lines using different field setups at various test sites and dates. Analyzing the data, we found a well-working calibration and a successful subsequent multi-layer inversion when relatively large lateral and vertical ECa values were found along the calibration line. However, we observed failure when either the measured or the predicted ECa range is 0.75 in the linear regression equations, universal calibration parameters were obtained. Since the inversion of universally calibrated EMI-ECa returned similar subsurface structures as the ERT images, the results indicate that future ERT calibration measurements might become unnecessary. We also extended our three-layer inversion using one EMI sensor with 6 coil configurations to a combined multi-layer inversion of multiple sensors. Here, we preliminary show 4 and 5 layer inversion results of post-calibrated EMI-ECa measured above paleo-river channels with 24 coil configurations, i.e. DualEM plus a three- and a six coil CMD-MiniExplorer. Conclusively, the post-calibrated EMI-ECa data enable quantitative inversions reflecting large-scale vadose zone properties.
Energy Technology Data Exchange (ETDEWEB)
Sáenz-Trevizo, A.; Amézaga-Madrid, P.; Pizá-Ruiz, P.; Antúnez-Flores, W.; Ornelas-Gutiérrez, C.; Miki-Yoshida, M., E-mail: mario.miki@cimav.edu.mx
2015-07-15
Core–shell nanorod structures were prepared by a sequential synthesis using an aerosol assisted chemical vapor deposition technique. Several samples consisting of ZnO nanorods were initially grown over TiO{sub 2} film-coated borosilicate glass substrates, following the synthesis conditions reported elsewhere. Later on, a uniform layer consisting of individual Al, Ni, Ti or Fe oxides was grown onto ZnO nanorod samples forming the so-called single MO{sub x}/ZnO nanorod core–shell structures, where MO{sub x} was the metal oxide shell. Additionally, a three-layer core–shell sample was developed by growing Fe, Ti and Fe oxides alternately, onto the ZnO nanorods. The microstructure of the core–shell materials was characterized by grazing incidence X-ray diffraction, scanning and transmission electron microscopy. Energy dispersive X-ray spectroscopy was employed to corroborate the formation of different metal oxides. X-ray diffraction outcomes for single core–shell structures showed solely the presence of ZnO as wurtzite and TiO{sub 2} as anatase. For the multi-layered shell sample, the existence of Fe{sub 2}O{sub 3} as hematite was also detected. Morphological observations suggested the existence of an outer material grown onto the nanorods and further microstructural analysis by HR-STEM confirmed the development of core–shell structures in all cases. These studies also showed that the individual Al, Fe, Ni and Ti oxide layers are amorphous; an observation that matched with X-ray diffraction analysis where no apparent extra oxides were detected. For the multi-layered sample, the development of a shell consisting of three different oxide layers onto the nanorods was found. Overall results showed that no alteration in the primary ZnO core was produced during the growth of the shells, indicating that the deposition technique used herein was and it is suitable for the synthesis of homogeneous and complex nanomaterials high in quality and purity. In addition
International Nuclear Information System (INIS)
Core–shell nanorod structures were prepared by a sequential synthesis using an aerosol assisted chemical vapor deposition technique. Several samples consisting of ZnO nanorods were initially grown over TiO2 film-coated borosilicate glass substrates, following the synthesis conditions reported elsewhere. Later on, a uniform layer consisting of individual Al, Ni, Ti or Fe oxides was grown onto ZnO nanorod samples forming the so-called single MOx/ZnO nanorod core–shell structures, where MOx was the metal oxide shell. Additionally, a three-layer core–shell sample was developed by growing Fe, Ti and Fe oxides alternately, onto the ZnO nanorods. The microstructure of the core–shell materials was characterized by grazing incidence X-ray diffraction, scanning and transmission electron microscopy. Energy dispersive X-ray spectroscopy was employed to corroborate the formation of different metal oxides. X-ray diffraction outcomes for single core–shell structures showed solely the presence of ZnO as wurtzite and TiO2 as anatase. For the multi-layered shell sample, the existence of Fe2O3 as hematite was also detected. Morphological observations suggested the existence of an outer material grown onto the nanorods and further microstructural analysis by HR-STEM confirmed the development of core–shell structures in all cases. These studies also showed that the individual Al, Fe, Ni and Ti oxide layers are amorphous; an observation that matched with X-ray diffraction analysis where no apparent extra oxides were detected. For the multi-layered sample, the development of a shell consisting of three different oxide layers onto the nanorods was found. Overall results showed that no alteration in the primary ZnO core was produced during the growth of the shells, indicating that the deposition technique used herein was and it is suitable for the synthesis of homogeneous and complex nanomaterials high in quality and purity. In addition, materials absorptance determined from
Cortesi, M; Mittig, W; Limonge, Y Ayyad; Bazin, D; Yurkon, J; Stolz, A
2016-01-01
The operating principle and performances of the Multi-layer Thick Gaseous Electron Multiplier (M-THGEM) is presented. The M-THGEM is a novel hole-type gaseous electron multiplier produced by multi-layer printed circuit board technology; it consists of a densely perforated assembly of multiple insulating substrate sheets (e.g., FR-4), sandwiched between thin metallic-electrode layers. The electron avalanche processes occur along the successive multiplication stages within the M-THGEM holes, under the action of strong dipole fields resulting from the application of suitable potential differences between the electrodes. The present work focuses on investigation of two different geometries: a two-layer M-THGEM (either as single or double-cascade detector) and a single three-layer M-THGEM element, tested in various low-pressure He-based gas mixtures. The intrinsically robust confinement of the avalanche volume within the M-THGEM holes provides an efficient suppression of the photon-induced secondary effects, resul...
Multi-Layer Forecast Project of Rain-Induced Debris Flow
Institute of Scientific and Technical Information of China (English)
ZHANG Jing-hong; WEI Fang-qiang; LIU Shu-zhen; CUI Peng; ZHONG Dun-lun; LI Fa-bin; GAO Ke-chang
2005-01-01
Based on four kinds of methods--numerical weather prediction model, cloud image of stationary meteorological satellite, echo image of meteorological radar and telemetric rain gauge, multi space-time scale precipitation prediction products have been achieved, and multi-layer project of debris flow forecast is established with different space-time scale to get different forecast precision. The forecast system has the advantages in combination of regions and ravines, rational compounding of time and space scale. The project, which has debris flow forecast models of Sichuan province, Liangshan district and single ravine, can forecast debris flow in 3 layers and meets the demand of hazard mitigation in corresponding layer.
Degradation of Multi-Layer Insulation (MLI) Retrieved from the Hubble Space Telescope
Mohammed, Jelila S.; deGroh, Kim, K.
2011-01-01
Multi-Layer Insulation (MLI) returned during Servicing Mission 4 are still being analyzed. Analysis has revealed degradation of optical, thermal, and mechanical properties, increased crystallinity, and reduction in fluorine/carbon ratio of aluminized-Teflon fluorinated ethylene propylene (Al-FEP) FEP. These material properties can be affected by high temperatures on orbit, increased radiation exposure, and in some cases contamination from materials in close proximity to the insulation on orbit. Preliminary results support conclusions of previous studies: areas of Al-FEP that received higher levels of solar exposure show more degradation (high temperatures and radiation combined).
Detection of Multi-Layer and Vertically-Extended Clouds Using A-Train Sensors
Joiner, J.; Vasilkov, A. P.; Bhartia, P. K.; Wind, G.; Platnick, S.; Menzel, W. P.
2010-01-01
The detection of mUltiple cloud layers using satellite observations is important for retrieval algorithms as well as climate applications. In this paper, we describe a relatively simple algorithm to detect multiple cloud layers and distinguish them from vertically-extended clouds. The algorithm can be applied to coincident passive sensors that derive both cloud-top pressure from the thermal infrared observations and an estimate of solar photon pathlength from UV, visible, or near-IR measurements. Here, we use data from the A-train afternoon constellation of satellites: cloud-top pressure, cloud optical thickness, the multi-layer flag from the Aqua MODerate-resolution Imaging Spectroradiometer (MODIS) and the optical centroid cloud pressure from the Aura Ozone Monitoring Instrument (OMI). For the first time, we use data from the CloudSat radar to evaluate the results of a multi-layer cloud detection scheme. The cloud classification algorithms applied with different passive sensor configurations compare well with each other as well as with data from CloudSat. We compute monthly mean fractions of pixels containing multi-layer and vertically-extended clouds for January and July 2007 at the OMI spatial resolution (l2kmx24km at nadir) and at the 5kmx5km MODIS resolution used for infrared cloud retrievals. There are seasonal variations in the spatial distribution of the different cloud types. The fraction of cloudy pixels containing distinct multi-layer cloud is a strong function of the pixel size. Globally averaged, these fractions are approximately 20% and 10% for OMI and MODIS, respectively. These fractions may be significantly higher or lower depending upon location. There is a much smaller resolution dependence for fractions of pixels containing vertically-extended clouds (approx.20% for OMI and slightly less for MODIS globally), suggesting larger spatial scales for these clouds. We also find higher fractions of vertically-extended clouds over land as compared with
Modeling of Nonlinear Propagation in Multi-layer Biological Tissues for Strong Focused Ultrasound
Institute of Scientific and Technical Information of China (English)
FAN Ting-Bo; LIU Zhen-Bo; ZHANG Zhe; ZHANG DONG; GONG Xiu-Fen
2009-01-01
A theoretical model of the nonlinear propagation in multi-layered tissues for strong focused ultrasound is proposed. In this model, the spheroidal beam equation (SBE) is utilized to describe the nonlinear sound propagation in each layer tissue, and generalized oblique incidence theory is used to deal with the sound transmission between two layer tissues. Computer simulation is performed on a fat-muscle-liver tissue model under the irradiation of a 1 MHz focused transducer with a large aperture angle of 35°. The results demonstrate that the tissue layer would change the amplitude of sound pressure at the focal region and cause the increase of side petals.
Social Media for Social Innovation: towards a multi-layered analytic framework
Pavan, Elena; Diani, Mario; Padovani, Claudia
2011-01-01
This paper proposes some ideas to ground a multi-layered analytic framework for the study of how social media (i.e., a class of specific Internet-based communication tools) can be strategically employed to promote social innovation (i.e., the actual consolidation of norms guiding democratic and participated policy-making processes). We propose to account simultaneously for a) the type of users; b) the type of Internet-enabled communication; c) the different facets of political processes; d) t...
Adaptive Multi-Layered Space-Time Block Coded Systems in Wireless Environments
Al-Ghadhban, Samir
2014-12-23
© 2014, Springer Science+Business Media New York. Multi-layered space-time block coded systems (MLSTBC) strike a balance between spatial multiplexing and transmit diversity. In this paper, we analyze the block error rate performance of MLSTBC. In addition, we propose an adaptive MLSTBC schemes that are capable of accommodating the channel signal-to-noise ratio variation of wireless systems by near instantaneously adapting the uplink transmission configuration. The main results demonstrate that significant effective throughput improvements can be achieved while maintaining a certain target bit error rate.
Thermal processes in multi-layered second generation HTSC under swift heavy ion irradiation
International Nuclear Information System (INIS)
On the basis of the thermal spike model, the estimations with regard to ribbons of the second generation Ag/YBaCuO/MgO/Hastelloy HTSC under irradiation by Ar, Kr and Xe ions with an energy of about 1.2 MeV/a. m. u. have been carried out. The obtained results have been compared with available experimental data. In addition, the possibility of processes such as melting, recrystallization, amorphization and other phase transitions in multi-layered structures under ion irradiation has been studied
Neutronic Analysis of Flux Dispersion in a Multi-Layered, (D-T) Driven Hybrid Blanket
İPEK, Osman
2000-01-01
The concept of `hybrid blanket' is based on the placement of the nuclear fuel layer, which is a fertile material and fissionable by the fusion neutrons, at the front or the rear sides of the tritium breeding zone so that, in addition to gaining fission energy, a fissile fuel is produced. The neutronic flux distribution (neutron spectrum) along the radial direction varies with the type of material and the geometry used in the blanket, and also according to whether it is multi-layered or s...
Multi-Layer Mobility Load Balancing in a Heterogeneous LTE Network
DEFF Research Database (Denmark)
Fotiadis, Panagiotis; Polignano, Michele; Laselva, Daniela;
2012-01-01
This paper analyzes the behavior of a distributed Mobility Load Balancing (MLB) scheme in a multi-layer 3GPP (3rd Generation Partnership Project) Long Term Evolution (LTE) deployment with different User Equipment (UE) densities in certain network areas covered with pico cells. Target of the study...... is to evaluate MLB in terms of efficient pico cell utilization and macro layer load balancing (LB). The analysis focuses on video streaming traffic due to specific service characteristics (e.g. play-out buffer delay/ jitter protection) that might make any mobility performance degradation transparent...
Functional Multi-Layer Perceptron: a Nonlinear Tool for Functional Data Analysis
Rossi, Fabrice
2005-01-01
In this paper, we study a natural extension of Multi-Layer Perceptrons (MLP) to functional inputs. We show that fundamental results for classical MLP can be extended to functional MLP. We obtain universal approximation results that show the expressive power of functional MLP is comparable to that of numerical MLP. We obtain consistency results which imply that the estimation of optimal parameters for functional MLP is statistically well defined. We finally show on simulated and real world data that the proposed model performs in a very satisfactory way.
Carbon nano-onions (multi-layer fullerenes: chemistry and applications
Directory of Open Access Journals (Sweden)
Juergen Bartelmess
2014-11-01
Full Text Available This review focuses on the development of multi-layer fullerenes, known as carbon nano-onions (CNOs. First, it briefly summarizes the most important synthetic pathways for their preparation and their properties and it gives the reader an update over new developments in the recent years. This is followed by a discussion of the published synthetic procedures for CNO functionalization, which are of major importance when elucidating future applications and addressing drawbacks for possible applications, such as poor solubility in common solvents. Finally, it gives an overview over the fields of application, in which CNO materials were successfully implemented.
Modeling Liner Shipping Service Selection and Container Flows using a Multi-layer Network
DEFF Research Database (Denmark)
Karsten, Christian Vad; Balakrishnan, Anant
We introduce a new formulation for the tactical planning problem facing container shipping companies of selecting the best subset of sailing routes from a given pool of candidate routes so as to maximize profit. Since most containers are sent directly or transshipped at most twice in current liner...... shipping networks, we impose limits on the number of transshipments for each container (which most previous models do not incorporate). Our multi-layer multi-commodity model associates one commodity with each container origin port, and decides the route for each commodity on a logical network layer whose...
Study on the Relation between Individual Layer and Multi-layered Nonwoven Geotextile Permeability
Institute of Scientific and Technical Information of China (English)
刘丽芳; 储才元
2003-01-01
Water permeability is an important property of nonwoven geotextiles used in drainage field, and usually it is obtained by testing individual layer or multi-layered nonwoven geotextiles. However, the permeability coefficient tested by using different layers would be different for the same nonwoven geotextile. In this paper, the relation between them is studied based on Darcy's law. The study shows that vertical permeability coefficients are theoretically invariable no matter how many layers are tested; but experimental results show that vertical permeability coefficients decrease with the increase of nonwoven geotextile layers number.
Tunable electromagnetic chirality induced by graphene inclusions in multi-layered metamaterials
Rizza, Carlo; Ciattoni, Alessandro
2013-01-01
We theoretically investigate the electromagnetic response of a novel class of multi-layered metamaterials obtained by alternating graphene sheets and dielectric layers, the whole structure not exhibiting a plane of reflection symmetry along the stacking direction. We show that the electromagnetic response of the structure is characterized by a magneto-electric coupling described by an effective chiral parameter. Exploiting the intrinsic tunability of the graphene-light coupling, we prove that one can tune both the dielectric and the chiral electromagnetic response by varying the graphene chemical potential through external voltage gating.
Institute of Scientific and Technical Information of China (English)
ZHANG Hui; ZHANG Shu-Yi; FAN Li
2009-01-01
A model of high-overtone bulk acoustic resonators is used to study the effects of thickness deviation of elastic plates on resonance frequency spectra in planar multi-layered systems. The resonance frequency shifts induced by the thickness deviations of the elastic plates periodically vary with the resonance order, which depends on the acoustic impedance ratios of the elastic plates to piezoelectric patches. Additionally, the center lines of the frequency shift oscillations Hnearly change with the orders of the resonance modes, and their slopes are sensitive to the thickness deviations of the plates, which can be used to quantitatively evaluate the thickness deviations.
DEFF Research Database (Denmark)
Tavares, Luciana; Cadelano, Michele; Quochi, Francesco;
2015-01-01
Multi-layered epitaxial nanofibers are exemplary model systems for the study of exciton dynamics and lasing in organic materials due to their well-defined morphology, high luminescence efficiencies, and color tunability. We resort to temperature-dependent cw and picosecond photoluminescence (PL......-to-6T resonance-energy transfer efficiency, and the observed weak PL temperature dependence of the 6T acceptor material together result in an exceptionally high optical emission performance of this all-organic material system, thus making it well suited for example for organic light-emitting devices....
Multi-Layer 5G Mobile Phone Antenna for Multi-User MIMO Communications
Ojaroudiparchin, Naser; Shen, Ming; Pedersen, Gert F.
2015-01-01
In this study, a new design of multi-layer phased array antenna for millimeter-wave (mm-Wave) fifth generation (5G) mobile terminals is proposed. The proposed linear phased array antenna is designed on four layers of the Rogers RT5880 substrates to operate at 28 GHz which is under consideration for 5G wireless communications. Two identical linear sub arrays can be simultaneously used at different sides of the mobile-phone printed circuit board (PCB) for operation in diversity or multiple-inpu...
Apply Multi-Layer Perceptrons Neural Network for Off-Line Signature Verification and Recognition
Directory of Open Access Journals (Sweden)
Suhail Odeh
2011-11-01
Full Text Available This paper discusses the applying of Multi-layer perceptrons for signature verification and recognition using a new approach enables the user to recognize whether a signature is original or a fraud. The approach starts by scanning images into the computer, then modifying their quality through image enhancement and noise reduction, followed by feature extraction and neural network training, and finally verifies the authenticity of the signature. The paper discusses the different stages of the process including: image pre-processing, feature extraction and pattern recognition through neural networks.
Modelling the dynamic pile-soil-pile interaction in a multi-layered half-space
Hamad, Waleed; Ntotsios, Evangelos; Hunt, Hugh; Hussein, M.F.M.; Thompson, D. J.; Talbot, James
2015-01-01
Within the context of railway ground-borne vibration, the dynamic pile-soil-pile interaction remains an area that has not been sufficiently investigated. Whilest a number of researchers have scrutinised the vibration response of piled-foundations, their approaches exhibit a compromise between computation time and solution accuracy. In this paper, two models of piled-foundations in a multi-layered half-space are presented; one is an efficient semi-analytical model and another is a fully-couple...
Development of multi-layer thin film bolometer with fast time response and high sensitivity
International Nuclear Information System (INIS)
Impurity radiation loss is one of major cooling mechanisms in a fusion plasma. A multi-layer thin film bolometer with high sensitivity and fast time response has been developed for the measurement of radiation energy loss of a screw pinch plasma in TPE-2 device. The construction and test of the bolometer are described. High sensitivity of 2.5 mV/μ Joule and fast time response of 10 μsec with cooling time of 50 msec are obtained. (author)
Mass Conservation in Modeling Moisture Diffusion in Multi-Layer Carbon Composite Structures
Nurge, Mark A.; Youngquist, Robert C.; Starr, Stanley O.
2009-01-01
Moisture diffusion in multi-layer carbon composite structures is difficult to model using finite difference methods due to the discontinuity in concentrations between adjacent layers of differing materials. Applying a mass conserving approach at these boundaries proved to be effective at accurately predicting moisture uptake for a sample exposed to a fixed temperature and relative humidity. Details of the model developed are presented and compared with actual moisture uptake data gathered over 130 days from a graphite epoxy composite sandwich coupon with a Rohacell foam core.
A housing-demographic multi-layered nonlinear model to test regulation strategies
Ramon Huerta; Fernando Corbacho; Luis F. Lago-Fernandez
2008-01-01
We propose a novel multi-layered nonlinear model that is able to capture and predict the housing-demographic dynamics of the real-state market by simulating the transitions of owners among price-based house layers. This model allows us to determine which parameters are most effective to smoothen the severity of a potential market crisis. The International Monetary Fund (IMF) has issued severe warnings about the current real-state bubble in the United States, the United Kingdom, Ireland, the N...
Layering, interface and edge effects in multi-layered composite medium
Datta, S. K.; Shah, A. H.; Karunesena, W.
1990-01-01
Guided waves in a cross-ply laminated plate are studied. Because of the complexity of the exact dispersion equation that governs the wave propagation in a multi-layered fiber-reinforced plate, a stiffness method that can be applied to any number of layers is presented. It is shown that, for a sufficiently large number of layers, the plate can be modeled as a homogeneous anisotropic plate. Also studied is the reflection of guided waves from the edge of a multilayered plate. These results are quite different than in the case of a single homogeneous plate.
Sorting out meandering and braiding: discriminating formative conditions and stratigraphy
Kleinhans, M. G.; van de Lageweg, W. I.; Schuurman, F.; Van Dijk, W. M.
2011-12-01
For various river channel patterns, the necessary formative conditions differ, but how is not entirely understood. Furthermore, not only the morphology and dynamics differ, but also the resulting stratigraphy differs, of which understanding is required to infer past environmental conditions and predict reservoir behaviour. Our objective is to identify the necessary and sufficient conditions for forming dynamic meandering and braided rivers. We reproduced both patterns experimentally and with a physics-based numerical model, and produced synthetic stratification from bed elevation maps and control lacquer peels for the experiments. Experimental meandering was produced using a mixture of poorly sorted sediment and silt-sized silica flour and a transversely moving inflow boundary. Braiding was produced in exactly the same conditions but without the silica flour. These experiments represent gravel-bed rivers in nature, where both experimental meandering and braiding channels were close to the transition between the types. Onset meandering was also produced in the numerical model (Delft3D) with a similar transversely moving inflow boundary, whilst braided rivers formed with fixed inflow or some noise on the transverse discharge distribution at the inflow boundary. The silica flour deposited on crevasse splays and in chute channels, forming new floodplain. This caused much less chute cutoffs and stronger banks. The resulting meandering river formed multiple sets of scroll bars forming pointbars, overlain by splays and floodplain. The braided river, in contrast, showed mid-channel bars and multiple active channels, faster and more haphazard bar and channel migration, and frequent chute cutoffs. Apart from the floodplain, stratification in meandering rivers consisted of sigmoidally stratified units formed by scroll bars and channel fills, usually formed after chute cutoff. Braided rivers had similar units but much smaller and more. In both cases the highest preservation
Mechanical properties of triaxially braided composites - Experimental and analytical results
Masters, John E.; Foye, Raymond L.; Pastore, Christopher M.; Gowayed, Yasser A.
1993-01-01
This paper investigates the unnotched tensile properties of two-dimensional (2D) triaxial braid-reinforced composites both experimentally and analytically. The materials are graphite fibers in an epoxy matrix. Three different reinforcing fiber architectures were considered. There were considerable differences in the observed elastic constants from different size strain gage and extensometer readings. Larger strain gages gave more consistent results and correlated better with the extensometer readings. Experimental strains correlated reasonably well with analytical predictions in the longitudinal, 0 deg, fiber direction but not in the transverse direction. Tensile strength results were not always predictable even in reinforcing directions. Minor changes in braid geometry led to disproportionate strength variations. The unit cell structure of the triaxial braid was discussed with the assistance of computer analysis of the microgeometry. Photomicrographs of braid geometry were used to improve upon the computer graphics representations of unit cells. These unit cells were used to predict the elastic moduli with various degrees of sophistication. The simple and the complex analyses were generally in agreement, but none adequately matched the experimental results for all the braids.
Heat conduction analysis of multi-layered FGMs considering the finite heat wave speed
International Nuclear Information System (INIS)
Highlights: ► Using a layerwise-incremental differential quadrature for heat transfer of FGMs. ► Superior accuracy with fewer degrees of freedom of the method with respect to FEM. ► Considering multi-layered functionally graded materials. ► Hyperbolic heat transfer analysis of thermal system with heat generation. ► Showing the effect of heat wave speed on thermal characteristic of the system. - Abstract: In this work, the heat conduction with finite wave heat speed of multi-layered domain made of functionally graded materials (FGMs) subjected to heat generation is simulated. For this purpose, the domain is divided into a set of mathematical layers, the number of which can be equal or greater than those of the physical layers. Then, in each mathematical layer, the non-Fourier heat transfer equations are employed. Since, the governing equations have variable coefficients due to FGM properties, as an efficient and accurate method the differential quadrature method (DQM) is adopted to discretize both spatial and temporal domains in each layer. This results in superior accuracy with fewer degrees of freedom than conventional finite element method (FEM). To verify this advantages through some comparison studies, a finite element solution are also obtained. After demonstrating the convergence and accuracy of the method, the effects of heat wave speed for two different set of boundary conditions on the temperature distribution and heat flux of the domain are studied.
Estimating Deliverability in Multi-Layered Gas Reservoirs Using Artificial Intelligence
Al-Arfaj, Malik Khalid
In this research, an artificial intelligence (AI) model has been created to estimate the production rate of each layer in a multi-layered gas reservoir using static properties such as those obtained from well logging, in addition to dynamic properties such as pressure. This approach will be helpful in several reservoir engineering applications, such as understanding layers' depletion, or targeting specific layers for workover. It could also be used for PLT analysis where the measured PLT values are compared to the expected values and a variance analysis could be performed. Data were collected from more than 100 wells in a certain reservoir spanning over four fields. They were combined in related input variables and fed to the AI model for learning purposes. To compare different AI methods, the data were fed to 5 methods, namely ANFIS, MLP, RBF, SVM, and GRNN, and results were optimized for each method. Between the tested AI methods, SVM and GRNN performed best as shown by a low mean absolute percentage error and a very high correlation coefficient. This research shows promising use for AI methods in estimating production rate from each layer in a multi-layered gas reservoir.
Lattice Boltzmann method for short-pulsed laser transport in a multi-layered medium
International Nuclear Information System (INIS)
We construct a lattice Boltzmann method (LBM) for transient radiative transfer in one-dimensional multi-layered medium with distinct refractive index in each layer. The left boundary is irradiated normally by a short-pulsed laser. The Fresnel interfaces conditions, which incorporate reflection and refraction, are used at the boundaries and the interfaces. Based on the Fresnel's law and Snell's law, the interfacial intensity formulas are introduced. The collimated and diffuse intensities are treated individually. At a transient time step, the collimated component is first solved by LBM and then embedded into the transient radiative transfer equation as a source term. To keep the consistency of the directions in all the layers, angular interpolation of the intensities at the interfaces is adopted. The transient radiative transfer in a two-layer medium is first investigated, and the time-resolved results are validated by comparing with those by the Monte Carlo method (MCM). Of particular interest, the angular intensities along the slab at different times are presented to illustrate a variety of interesting phenomena, and the discontinuous nature of the intensity at the interfaces is discussed. The effects of various parameters on the time-resolved signals are examined. - Highlights: • Transient radiative transfer in a multi-layered medium is solved by LBM. • The boundary and interfaces are all considered as Fresnel surfaces. • The LBM solution for the collimated pulse is derived. • Discontinuous nature of the intensity at the interface is illustrated and discussed
A mixture model for robust point matching under multi-layer motion.
Directory of Open Access Journals (Sweden)
Jiayi Ma
Full Text Available This paper proposes an efficient mixture model for establishing robust point correspondences between two sets of points under multi-layer motion. Our algorithm starts by creating a set of putative correspondences which can contain a number of false correspondences, or outliers, in addition to the true correspondences (inliers. Next we solve for correspondence by interpolating a set of spatial transformations on the putative correspondence set based on a mixture model, which involves estimating a consensus of inlier points whose matching follows a non-parametric geometrical constraint. We formulate this as a maximum a posteriori (MAP estimation of a Bayesian model with hidden/latent variables indicating whether matches in the putative set are outliers or inliers. We impose non-parametric geometrical constraints on the correspondence, as a prior distribution, in a reproducing kernel Hilbert space (RKHS. MAP estimation is performed by the EM algorithm which by also estimating the variance of the prior model (initialized to a large value is able to obtain good estimates very quickly (e.g., avoiding many of the local minima inherent in this formulation. We further provide a fast implementation based on sparse approximation which can achieve a significant speed-up without much performance degradation. We illustrate the proposed method on 2D and 3D real images for sparse feature correspondence, as well as a public available dataset for shape matching. The quantitative results demonstrate that our method is robust to non-rigid deformation and multi-layer/large discontinuous motion.
Lee, Wonhye; Debasitis, Jason Cushing; Lee, Vivian Kim; Lee, Jong-Hwan; Fischer, Krisztina; Edminster, Karl; Park, Je-Kyun; Yoo, Seung-Schik
2009-03-01
We present a method to create multi-layered engineered tissue composites consisting of human skin fibroblasts and keratinocytes which mimic skin layers. Three-dimensional (3D) freeform fabrication (FF) technique, based on direct cell dispensing, was implemented using a robotic platform that prints collagen hydrogel precursor, fibroblasts and keratinocytes. A printed layer of cell-containing collagen was crosslinked by coating the layer with nebulized aqueous sodium bicarbonate. The process was repeated in layer-by-layer fashion on a planar tissue culture dish, resulting in two distinct cell layers of inner fibroblasts and outer keratinocytes. In order to demonstrate the ability to print and culture multi-layered cell-hydrogel composites on a non-planar surface for potential applications including skin wound repair, the technique was tested on a poly(dimethylsiloxane) (PDMS) mold with 3D surface contours as a target substrate. Highly viable proliferation of each cell layer was observed on both planar and non-planar surfaces. Our results suggest that organotypic skin tissue culture is feasible using on-demand cell printing technique with future potential application in creating skin grafts tailored for wound shape or artificial tissue assay for disease modeling and drug testing. PMID:19108884
Penetration of a Small Caliber Projectile into Single and Multi-layered Targets
Directory of Open Access Journals (Sweden)
Riad A.M.
2010-06-01
Full Text Available The normal penetration of armor-piercing projectiles into single and multi-layered steel plates has been investigated. An experimental program has been conducted to study the effect of spaced and in-contact layered targets on their ballistic resistance. Armor piercing projectiles with caliber of 7.62 mm were fired against a series of single and multi-layered steel targets. The projectile impact velocities were ranged from 300-600 m/s, whereas the total thicknesses of the tested single, spaced and in-contact layered steel targets were 3 mm. The penetration process of different tested target configurations has been simulated using Autodayn-2D hydrocode. The experimental measurements of the present work were used to discuss the effect of impact velocity, target configurations and number of layers of different spaced and in-contact layered steel targets on their ballistic resistance. In addition, the post-firing examination of the tested targets over the used impact velocity range showed that the single and each layer of spaced and in-contact laminated steel targets were failed by petalling. Finally, the obtained experimental measurements were compared with the corresponding numerical results of Autodyn-2D hydrocode, good agreement was generally obtained.
Thermal conductivities of single- and multi-layer phosphorene: a molecular dynamics study.
Zhang, Ying-Yan; Pei, Qing-Xiang; Jiang, Jin-Wu; Wei, Ning; Zhang, Yong-Wei
2016-01-01
As a new two-dimensional (2D) material, phosphorene has drawn growing attention owing to its novel electronic properties, such as layer-dependent direct bandgaps and high carrier mobility. Herein we investigate the in-plane and cross-plane thermal conductivities of single- and multi-layer phosphorene, focusing on geometrical (sample size, orientation and layer number) and strain (compression and tension) effects. A strong anisotropy is found in the in-plane thermal conductivity with its value along the zigzag direction being much higher than that along the armchair direction. Interestingly, the in-plane thermal conductivity of multi-layer phosphorene is insensitive to the layer number, which is in strong contrast to that of graphene where the interlayer interactions strongly influence the thermal transport. Surprisingly, tensile strain leads to an anomalous increase in the in-plane thermal conductivity of phosphorene, in particular in the armchair direction. Both the in-plane and cross-plane thermal conductivities can be modulated by external strain; however, the strain modulation along the cross-plane direction is more effective and thus more tunable than that along the in-plane direction. Our findings here are of great importance for the thermal management in phosphorene-based nanoelectronic devices and for thermoelectric applications of phosphorene. PMID:26632915
Zhang, Haowei; Gao, Yanni; Yuan, Chengmei; Liu, Ying; Ding, Yuqing
2015-06-01
Multi-layer perceptron (MLP) neural network belongs to multi-layer feedforward neural network, and has the ability and characteristics of high intelligence. It can realize the complex nonlinear mapping by its own learning through the network. Bipolar disorder is a serious mental illness with high recurrence rate, high self-harm rate and high suicide rate. Most of the onset of the bipolar disorder starts with depressive episode, which can be easily misdiagnosed as unipolar depression and lead to a delayed treatment so as to influence the prognosis. The early identifica- tion of bipolar disorder is of great importance for patients with bipolar disorder. Due to the fact that the process of early identification of bipolar disorder is nonlinear, we in this paper discuss the MLP neural network application in early identification of bipolar disorder. This study covered 250 cases, including 143 cases with recurrent depression and 107 cases with bipolar disorder, and clinical features were statistically analyzed between the two groups. A total of 42 variables with significant differences were screened as the input variables of the neural network. Part of the samples were randomly selected as the learning sample, and the other as the test sample. By choosing different neu- ral network structures, all results of the identification of bipolar disorder were relatively good, which showed that MLP neural network could be used in the early identification of bipolar disorder. PMID:26485974
Multi-layer 3D imaging using a few viewpoint images and depth map
Suginohara, Hidetsugu; Sakamoto, Hirotaka; Yamanaka, Satoshi; Suyama, Shiro; Yamamoto, Hirotsugu
2015-03-01
In this paper, we propose a new method that makes multi-layer images from a few viewpoint images to display a 3D image by the autostereoscopic display that has multiple display screens in the depth direction. We iterate simple "Shift and Subtraction" processes to make each layer image alternately. The image made in accordance with depth map like a volume slicing by gradations is used as the initial solution of iteration process. Through the experiments using the prototype stacked two LCDs, we confirmed that it was enough to make multi-layer images from three viewpoint images to display a 3D image. Limiting the number of viewpoint images, the viewing area that allows stereoscopic view becomes narrow. To broaden the viewing area, we track the head motion of the viewer and update screen images in real time so that the viewer can maintain correct stereoscopic view within +/- 20 degrees area. In addition, we render pseudo multiple viewpoint images using depth map, then we can generate motion parallax at the same time.
Directory of Open Access Journals (Sweden)
LADANI ANIKET
2011-06-01
Full Text Available The objective of this work was to develop multi layered matrix sustained release tablets of highly water soluble Venlafaxine hydrochloride using natural gums (HPMC K-100M and Xanthan gum. The tablets containing Venlafaxine hydrochloride 150 mg were prepared using hybrid wet granulation barrier layer technology, using Xanthan gum and HPMC K 100M as rate controlling ingredient in the middle layer and Xanthan gum in the barrier layers. After evaluation of physical characteristics of tablets, the dissolution studies were performed in 900 ml of distil water at 100 rpm using the USP XXIII basket apparatus up to 24 hrs. The triple layer tablet gives the release pattern similar to reference product. The radar diagram, similarity factor f2 were used to evaluate the similarity of test product with the reference product. The multi layered matrix tablets overcome the problem of nonlinearity associated with diffusion controlled matrix devices by reducing the surface area of drug containing layer exposed to dissolution medium. Different dissolution models were applied to the drug release data of the optimized batch to evaluate release mechanism and kinetics .Drug release kinetic of the optimized triple layered tablets best fits to Higuchi model where as the release exponent value obtained for Korsmeymer Peppas model was less than 0.45, which is beyond the limit of the model. Release mechanism appears to be complex mechanism of swelling, diffusion, erosion and barrier controlled.
Solid particle effects on heat transfer in a multi-layered molten pool with gas injection
International Nuclear Information System (INIS)
In the very unlikely event of a severe reactor accident involving core melt and pressure vessel failure, it is important to identify the circumstances that would allow the molten core material to cool down and resolidify, bringing core debris to a stable coolable state. To achieve this, it has been proposed to flood the cavity with water from above forming a layered structure where upward heat loss from the molten pool to the water will cause the core material to quench and solidify. In this situation the molten pool would become a three-phase mixture: e.g., a solid and liquid slurry formed by the molten pool as it cools to a temperature below the temperature of liquidus, agitated by the gases formed in the concrete ablation process. The present work quantifies the partition of the heat losses upward and downward in this multi-layered configuration, considering the influence of the viscosity and the solid fraction in the pool, from test data obtained from intermediate scale experiments at the University of Wisconsin-Madison. These experimental results show heat transfer behavior for multi-layered pools for a range of viscosities and solid fractions. These results are compared to previous experimental studies and well known correlations and models
Collaborative multi-layer network coding for cellular cognitive radio networks
Sorour, Sameh
2013-06-01
In this paper, we propose a prioritized multi-layer network coding scheme for collaborative packet recovery in underlay cellular cognitive radio networks. This scheme allows the collocated primary and cognitive radio base-stations to collaborate with each other, in order to minimize their own and each other\\'s packet recovery overheads, and thus improve their throughput, without any coordination between them. This non-coordinated collaboration is done using a novel multi-layer instantly decodable network coding scheme, which guarantees that each network\\'s help to the other network does not result in any degradation in its own performance. It also does not cause any violation to the primary networks interference thresholds in the same and adjacent cells. Yet, our proposed scheme both guarantees the reduction of the recovery overhead in collocated primary and cognitive radio networks, and allows early recovery of their packets compared to non-collaborative schemes. Simulation results show that a recovery overhead reduction of 15% and 40% can be achieved by our proposed scheme in the primary and cognitive radio networks, respectively, compared to the corresponding non-collaborative scheme. © 2013 IEEE.
Smart Grid as Multi-layer Interacting System for Complex Decision Makings
Bompard, Ettore; Han, Bei; Masera, Marcelo; Pons, Enrico
This chapter presents an approach to the analysis of Smart Grids based on a multi-layer representation of their technical, cyber, social and decision-making aspects, as well as the related environmental constraints. In the Smart Grid paradigm, self-interested active customers (prosumers), system operators and market players interact among themselves making use of an extensive cyber infrastructure. In addition, policy decision makers define regulations, incentives and constraints to drive the behavior of the competing operators and prosumers, with the objective of ensuring the global desired performance (e.g. system stability, fair prices). For these reasons, the policy decision making is more complicated than in traditional power systems, and needs proper modeling and simulation tools for assessing "in vitro" and ex-ante the possible impacts of the decisions assumed. In this chapter, we consider the smart grids as multi-layered interacting complex systems. The intricacy of the framework, characterized by several interacting layers, cannot be captured by closed-form mathematical models. Therefore, a new approach using Multi Agent Simulation is described. With case studies we provide some indications about how to develop agent-based simulation tools presenting some preliminary examples.
An experimental study on mechanical properties of GFRP braid-pultruded composite rods
Directory of Open Access Journals (Sweden)
2009-09-01
Full Text Available In this work, a conventional textile braiding machine was modified and added to a pultrusion line in order to produce glass fiber reinforced composite rods by braiding-pultrusion technique. Braid-pultruded (BP rods were produced with three braid roving linear densities and also with three different braid angles. To study the influence of overbraiding on mechanical properties of pultruded rods, unidirectional (UD rods, without braided fabric, were produced, as well. All rod types were subjected to tensile, bending and torsion tests. The experimental results showed that BP rods have considerably higher shear modulus, but lower tensile modulus and flexural rigidity than those of UD pultruded rods, when fiber volume fraction is kept constant. Moreover, rods produced with higher braid roving linear densities had better torsional, but lower tensile and flexural properties. The highest shear modulus was observed in BP rods with braid angle of 45°.
On M\\"{u}ger's centralizer for a certain class of braided fusion categories
Burciu, S.
2014-01-01
We provide a general formula for Mueger's centralizer of any fusion subcategory of a braided fusion category containing a tannakian subcategory. This entails a description for Mueger's centralizer of all fusion subcategories of a group theoretical braided fusion category.
Non-Abelian braid statistics versus projective permutation statistics
International Nuclear Information System (INIS)
Recent papers by Finkelstein, Galiautdinov, and co-workers [J. Math. Phys. 42, 1489 (2001); 42, 3299 (2001)] discuss a suggestion by Wilczek that non-Abelian projective representations of the permutation group can be used as a new type of particle statistics, valid in any dimension. Wilczek's suggestion was based in part on an analysis by Nayak and Wilczek (NW) of the non-Abelian representation of the braid group in a quantum Hall system. We point out that projective permutation statistics is not possible in a local quantum field theory as it violates locality, and show that the NW braid group representation is not equivalent to a projective representation of the permutation group. The structure of the finite image of the braid group in a 2n/2-1-dimensional representation is obtained
Teleportation, braid group and Temperley-Lieb algebra
International Nuclear Information System (INIS)
We explore algebraic and topological structures underlying the quantum teleportation phenomena by applying the braid group and Temperley-Lieb algebra. We realize the braid teleportation configuration, teleportation swapping and virtual braid representation in the standard description of the teleportation. We devise diagrammatic rules for quantum circuits involving maximally entangled states and apply them to three sorts of descriptions of the teleportation: the transfer operator, quantum measurements and characteristic equations, and further propose the Temperley-Lieb algebra under local unitary transformations to be a mathematical structure underlying the teleportation. We compare our diagrammatical approach with two known recipes to the quantum information flow: the teleportation topology and strongly compact closed category, in order to explain our diagrammatic rules to be a natural diagrammatic language for the teleportation
The braided single-stage protocol for quantum secure communication
Darunkar, Bhagyashri; Verma, Pramode K.
2014-05-01
This paper presents the concept and implementation of a Braided Single-stage Protocol for quantum secure communication. The braided single-stage protocol is a multi-photon tolerant secure protocol. This multi-photon tolerant protocol has been implemented in the laboratory using free-space optics technology. The proposed protocol capitalizes on strengths of the three-stage protocol and extends it with a new concept of braiding. This protocol overcomes the limitations associated with the three-stage protocol in the following ways: It uses the transmission channel only once as opposed to three times in the three-stage protocol, and it is invulnerable to man-in-the-middle attack. This paper also presents the error analysis resulting from the misalignment of the devices in the implementation. The experimental results validate the efficient use of transmission resources and improvement in the data transfer rate.
He, Meng; Zhao, Yanteng; Duan, Jiangjiang; Wang, Zhenggang; Chen, Yun; Zhang, Lina
2014-02-12
Novel onion-like and multi-layered tubular cellulose hydrogels were constructed, for the first time, from the cellulose solution in a 7% NaOH/12% urea aqueous solvent by changing the shape of the gel cores. In our findings, the contacting of the cellulose solution with the surface of the agarose gel rod or sphere loaded with acetic acid led to the close chain packing to form immediately a gel layer, as a result of the destruction of the cellulose inclusion complex by acid through inducing the cellulose self-aggregation. Subsequently, multi-layered cellulose hydrogels were fabricated via a multi-step interrupted gelation process. The size, layer thickness and inter-layer space of the multi-layered hydrogels could be controlled by adjusting the cellulose concentrations, the gel core diameter and the contacting time of the solid-liquid interface. The multi-layered cellulose hydrogels displayed good architectural stability and solvent resistance. Moreover, the hydrogels exhibited high compressive strength and excellent biocompatibility. L929 cells could adhere and proliferate on the surface of the layers and in interior space, showing great potential as tissue engineering scaffolds and cell culture carrier. This work opens up a new avenue for the construction of the high strength multi-layered cellulose hydrogels formed from inner to outside via a fast contact of solid-liquid interface. PMID:24405277
Template synthesis of braided gold nanowires with gemini surfactant-HAuCl{sub 4} aggregates
Energy Technology Data Exchange (ETDEWEB)
Wang Wentao; Han Yuchun; Gao Mingyuan, E-mail: gaomy@iccas.ac.cn; Wang Yilin, E-mail: yilinwang@iccas.ac.cn [Beijing National Laboratory for Molecular Sciences (BNLMS), Institute of Chemistry, Chinese Academy of Sciences, Key Laboratory of Colloid and Interface Science (China)
2013-01-15
One-dimensional braided gold nanowires with 40-50 nm in width and several micrometers in length which were fabricated by using cationic gemini surfactant hexamethylene-1,6-bis (dodecyl dimethylammonium bromide) (C{sub 12}C{sub 6}C{sub 12}Br{sub 2}). Through simply regulating the mole ratio of C{sub 12}C{sub 6}C{sub 12}Br{sub 2} to HAuCl{sub 4}, the morphology of the gold products changed into nanoparticles and nanowires. The CryoTEM images indicated that the C{sub 12}C{sub 6}C{sub 12}Br{sub 2}/HAuCl{sub 4} mixture formed spherical or fibrillar aggregates depending on the mole ratio of C{sub 12}C{sub 6}C{sub 12}Br{sub 2} to HAuCl{sub 4}, which performed as the versatile templates for morphology-controlled synthesis of the multiple gold nanomaterials. The HRTEM and SAED results suggested the nanowires and braided nanowires were polycrystalline. The gold nanostructure displayed a time-dependent growth process, i.e., first the nanoparticles arranged in one dimension, and then assembled into nanowires. Therefore, a template-directed aggregation and fusion process of nanoparticles is proposed for the formation of the one-dimensional gold nanomaterials. The braided nanowires exhibited a higher catalytic activity in the reduction of p-nitroaniline than that of the nanowires. This gemini surfactant-based template provides a versatile strategy for the morphology-controlled synthesis of gold nanomaterials, and may be applied for the synthesis of other noble-metal nanomaterials.
Knots, Braids and BPS States in M-Theory
Grassi, Antonella; Guralnik, Zachary; Ovrut, Burt A.
2001-01-01
In previous work we considered M-theory five branes wrapped on elliptic Calabi-Yau threefold near the smooth part of the discriminant curve. In this paper, we extend that work to compute the light states on the worldvolume of five-branes wrapped on fibers near certain singular loci of the discriminant. We regulate the singular behavior near these loci by deforming the discriminant curve and expressing the singularity in terms of knots and their associated braids. There braids allow us to comp...
Self-sustained magnetic braiding in toroidal plasmas
International Nuclear Information System (INIS)
Theory for the magnetic braiding in toroidal plasmas, which is caused by microscopic pressure-gradient-driven turbulence, is developed. When the pressure gradient exceeds a threshold, the self-sustaining of the magnetic braiding and enhanced anomalous transport occur. The balance between the nonlinear destabilization and nonlinear stabilization, which determines the stationary turbulence, is solved analytically for the case of interchange mode. The enhanced thermal conductivity and magnetic perturbation amplitude as well as the threshold pressure gradient are obtained. Cusp-type catastrophe is predicted, allowing the abrupt burst of magnetic perturbations. (author)
Hydraulics of flows over and through multi-layered soils on mild slopes
Lin, Yen-Ti; Hsieh, Ping-Cheng
2015-04-01
In early researches overland flow was only considered for the case of a single soil layer. However, there are multiple layers of soils in reality, so this work considers not only the surface flow but also the subsurface flow passing the parallel multi-layered soils with a mild slope. The flow field is divided into a homogenous water layer and permeable parallel multi-layered soils with infinite thickness. The water flow in the top layer is described by the Navier-Stokes equations, and the pore water flow inside each soil layer is governed by the Biot's theory of poroelasticity. Both water flows are considered as laminar flows. After the boundary-value problem is formulated, the solution can be theoretically derived by the method of separation of variables. Then, the velocity profiles and shear stress profiles are investigated. The variation among each interface is especially important and thus is also discussed. As a result, the bottom slope of each layer and the soil type influence the profiles of flow velocity and shear stress significantly. Because the soil layers are considered permeable, the flow velocity profiles are nonzero at the interfaces among the layers. For a constant slope, the subsurface flow velocity is mainly affected by the soil porosity, i.e. the soil type, and it is continuous at the interface of each layer. Moreover, the distribution of shear stress in the water layer appears to be linear and the maximum value occurs at the interface of the water-soil matrix. The shear stress distribution for a certain soil or inside each soil layer approaches to zero except near the interfaces of soil layers since the flow velocity is nearly constant. To sum up, this study successfully presents the solution of water flows over and through multi-layered soils on mild slopes by an analytical approach. While the multiple layers degenerate into a single one, the solution is exactly the same as the previous research. This validates the present results.
Directory of Open Access Journals (Sweden)
Zheng LU
2014-12-01
Full Text Available In this research work, a method to estimate the dynamic characteristics of a multilayered pavement with bituminous or concrete materials is proposed. A mechanical model is established to investigate the dynamic displacement and stress of the multi-layered pavement structure. Both the flexible and the rigid pavements, corresponding to bituminous materials and concrete materials, respectively, are studied. The theoretical solutions of the multi-layered pavement structure are deduced considering the compatibility condition at the interface of the structural layers. By introducing FFT (Fast Fourier Transform algorithm, some numerical results are presented. Comparisons of the theoretical and experimental result implied that the proposed method is reasonable in predicting the stress and displacement of a multi-layered pavement with bituminous or concrete materials. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6071
International Nuclear Information System (INIS)
Stress corrosion cracking (SCC) has recently been observed in the nickel base alloy weld metal of dissimilar pipe joint used in pressurized water reactor (PWR) . Temper bead technique has been developed as one of repair procedures against SCC applicable in case that post weld heat treatment (PWHT) is difficult to carry out. In this regard, however it is essential to pass the property and performance qualification test to confirm the effect of tempering on the mechanical properties at repair welds before temper bead technique is actually used in practice. Thus the appropriate welding procedure conditions in temper bead technique are determined on the basis of the property and performance qualification testing. It is necessary for certifying the structural soundness and reliability at repair welds but takes a lot of work and time in the present circumstances. Therefore it is desirable to establish the reasonable alternatives for qualifying the property and performance at repair welds. In this study, mathematical modeling and numerical simulation procedures were developed for predicting weld bead configuration and temperature distribution during multi-layer repair welding process by temper bead technique. In the developed simulation technique, characteristics of heat source in temper bead welding are calculated from weld heat input conditions through the arc plasma simulation and then weld bead configuration and temperature distribution during temper bead welding are calculated from characteristics of heat source obtained through the coupling analysis between bead surface shape and thermal conduction. The simulation results were compared with the experimental results under the same welding heat input conditions. As the results, the bead surface shape and temperature distribution, such as Acl lines, were in good agreement between simulation and experimental results. It was concluded that the developed simulation technique has the potential to become useful for accurate
International Nuclear Information System (INIS)
Dual mechanical braiding experiments provide a useful tool with which to investigate the nature of interactions between rod-like molecules, for instance actin and DNA. In conditions close to molecular condensation, one would expect an appearance of a local minimum in the interaction potential between the two molecules. We investigate this situation, introducing an attractive component into the interaction potential, using a model developed for describing such experiments. We consider both attractive interactions that do not depend on molecular structure and those which depend on a DNA-like helix structure. In braiding experiments, an attractive term may lead to certain effects. A local minimum may cause molecules to collapse from a loosely braided configuration into a tight one, occurring at a critical value of the moment applied about the axis of the braid. For a fixed number of braid pitches, this may lead to coexistence between the two braiding states, tight and loose. Coexistence implies certain proportions of the braid are in each state, their relative size depending on the number of braid pitches. This manifests itself as a linear dependence in numerically calculated quantities as functions of the number of braid pitches. Also, in the collapsed state, the braid radius stays roughly constant. Furthermore, if the attractive interaction is helix dependent, the left-right handed braid symmetry is broken. For a DNA like charge distribution, using the Kornyshev–Leikin interaction model, our results suggest that significant braid collapse and coexistence only occurs for left handed braids. Regardless of the interaction model, the study highlights the possible qualitative physics of braid collapse and coexistence; and the role helix specific forces might play, if important. The model could be used to connect other microscopic theories of interaction with braiding experiments. (paper)
Biggio, Matteo; Giustiniani, Alessandro; Masi, Alessandro; Storace, Marco
2014-01-01
In this paper we provide an experimental characterization of creep and hysteresis in a multi layer piezoelectric actuator (PEA), taking into account their relationships in terms of memory structure. We fit the well-known log-t model to the response of the PEA when driven by piecewise-constant signals, and find that both the instantaneous and the delayed response of the PEA display hysteretic dependence on the voltage level. We investigate experimentally the dependence of the creep coefficient on the input history, by driving the PEA along first order reversal curves and congruent minor loops, and find that it displays peculiar features like strict congruence of the minor loops and discontinuities. We finally explain the observed experimental behaviors in terms of a slow relaxation of the staircase interface line in the Preisach plane.
Laser multi-layer cladding on ZM6 magnesium base alloy
Institute of Scientific and Technical Information of China (English)
Changjun Chen(陈长军); Dongsheng Wang(王东生); Maocai Wang(王茂才)
2003-01-01
A pulsed Nd: YAG laser is used in multi-layer cladding on ZM6 Mg base alloys. The microstructure isstudied with an optical microscope and a scanning electron microscope (SEM). The composition within thelayer was determined by electron probe microanalysis (EPMA). X-ray diffraction (XRD) was also used toinvestigate the phase of constitutes of the cladding zone. The results show that microstructure in solidifiedcladding layer changes much when treated by high energy laser beam. The microstructure of the ZM6alloy consists of α-Mg and Mg9Nd, while the L-ZM6 of α-Mg, Mg9Nd and c-Zr. The depth of the claddingis over 1 mm. Many fine particles were found to be distributed homogeneously throughout the matrix andthe columnar grain grows along substrate.
Electronic structures of single- and multi-layer epitaxial graphene on SiC (0001)
Kim, Seungchul; Ihm, Jisoon; Son, Young-Woo
2009-03-01
The electronic structures of single- and multi-layered epitaxial graphene on silicon carbide (0001) surface are studied theoretically. To calculate energy bands of the systems, we construct the simple Hamiltonian with tight-binding approximations. We confirm that the present simple model do give identical electronic structure to the previous ab-initio study on the single layer case [1]. We extend the model up to four epitaxial graphene layers to explain various interesting experimental findings. The roles of the coupling between graphenes and the buffer layer, and their large scale reconstructions to the electronic structures are also investigated. [1] S. Kim, J. Ihm, H. J. Choi, Y.-W. Son, Phys. Rev. Lett. 100, 176802 (2008).
Internal defect position analysis of a multi-layer chip using lock-in infrared microscopy
International Nuclear Information System (INIS)
An ultra-precise infrared microscope consisting of a high-resolution infrared objective lens and infrared sensors is utilized successfully to obtain location information on the plane and depth of local heat sources causing defects in a semiconductor device. In this study, multi-layer semiconductor chips are analyzed for the positional information of heat sources by using a lock-in infrared microscope. Optimal conditions such as focal position, integration time, current and lock-in frequency for measuring the accurate depth of the heat sources are studied by lock-in thermography. The location indicated by the results of the depth estimate, according to the change in distance between the infrared objective lens and the specimen is analyzed under these optimal conditions
Novel Intersection Type Recognition for Autonomous Vehicles Using a Multi-Layer Laser Scanner.
An, Jhonghyun; Choi, Baehoon; Sim, Kwee-Bo; Kim, Euntai
2016-01-01
There are several types of intersections such as merge-roads, diverge-roads, plus-shape intersections and two types of T-shape junctions in urban roads. When an autonomous vehicle encounters new intersections, it is crucial to recognize the types of intersections for safe navigation. In this paper, a novel intersection type recognition method is proposed for an autonomous vehicle using a multi-layer laser scanner. The proposed method consists of two steps: (1) static local coordinate occupancy grid map (SLOGM) building and (2) intersection classification. In the first step, the SLOGM is built relative to the local coordinate using the dynamic binary Bayes filter. In the second step, the SLOGM is used as an attribute for the classification. The proposed method is applied to a real-world environment and its validity is demonstrated through experimentation. PMID:27447640
Preparation of Fe-Al Binary System Intermetallic Compounds by Multi-Layered Roll-Bonding
Institute of Scientific and Technical Information of China (English)
Akio Nishimoto; Katsuya Akamatsu; Kazuyoshi Nakao; Kazuo Ichii; Tomohiro Hiraki
2004-01-01
Iron aluminides exhibit good resistance to high-temperature sulfidizing and oxidizing environments and potential for structural applications at high temperatures under corrosive environments. In this study, Fe-Al intermetallic compound was prepared by multi-layered roll-bonding of elemental Fe and Al foils. The process consisted of the accumulative roll-bonding (ARB) for making a laminated Fe/Al sheet and the subsequent heat treatment promoting a solid phase reaction in the laminated Fe/Al sheet. The microstructures produced at each processing stage were characterized by optical microscopy and scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS). Vickers microhardness testing was used for hardness determination. A homogeneous intermetallic compound of Fe3Al or FeAl could be obtained after the subsequent heat treatment for 1.8 ks at 973 K and for 10.8 ks at 1123 or 1173 K.
An Investigation on Corrosion Behavior of a Multi-layer Modified Aluminum Brazing Sheet
Directory of Open Access Journals (Sweden)
Liu Wei
2016-01-01
Full Text Available The corrosion behavior of a multi-layer modified aluminum brazing sheet (AA4045/3003Mod./AA7072/AA4045 was investigated. The results shows that, the existence of BDP, which forms at the interface between clad and core layer during brazing, changes the corrosion form of the air side of the material from inter-granular corrosion to local exfoliation corrosion. The addition of anti-corrosion layer makes the corrosion form of the water side from inter-granular corrosion into uniform exfoliation corrosion. Compared to the normal triple-layer brazing sheet at the same thickness, the time to perforation of the modified four-layer brazing sheet is increased by more than 200%.
International Nuclear Information System (INIS)
In this paper we provide an experimental characterization of creep and hysteresis in a multi-layer piezoelectric actuator (PEA), taking into account their relationships in terms of memory structure. We fit the well-known log-t model to the response of the PEA when driven by piecewise-constant signals, and find that both the instantaneous and the delayed response of the PEA display hysteretic dependence on the voltage level. We investigate experimentally the dependence of the creep coefficient on the input history, by driving the PEA along first-order reversal curves and congruent minor loops, and find that it displays peculiar features like strict congruence of the minor loops and discontinuities. We finally explain the observed experimental behaviors in terms of a slow relaxation of the staircase interface line in the Preisach plane
Failure characterization of nodular defects in multi-layer dielectric coatings
International Nuclear Information System (INIS)
Nodular defects in multi-layer dielectric coatings have been computer modeled to characterize the electro-mechanical responses to laser pulses with wavelengths of 1.06 μm and pulse lengths between 1 and 20 ns. The simulation begins with an axisymmetric electric field model using AMOS, a full-wave Maxwell solver with lossy (dispersive) electric and magnetic material models. Electric fields calculated by this code determine the spatial distribution of absorbed laser energy in the vicinity of the nodule. This data is linked to a thermal/stress model and mechanical calculations are executed using the general purpose finite element code COSMOS/M. The simulation estimates the transient temperature response of the nodule and the surrounding medium and predicts the dynamic stresses caused by the thermal impulse. This integrated computer process has been exercised to characterize failure of nodules as a function of defect characteristics, including seed size and depth
Advanced activity reporting in a multi-layered unattended ground sensor network
Joslin, Todd W.
2007-04-01
Sensor networks are emplaced throughout the world to remotely track activity. Typically, these sensors report data such as target direction or target classification. This information is reported to a personnel-based monitor or a command and control center. The ideal sensor system will have a long mission life capability and will report information-rich actionable intelligence with high data integrity at near real-time latency. This paper discusses a multi-layered approach that includes data fusion at the Sensor Node, Sensor Field, and Command and Control Center Layer to create cohesive reports that mitigate false alarms and multiple reports of the same target while providing accurate tracking data on a situational awareness level. This approach is influenced by low-power architecture, and designed to maximize information density and reduce flooding of sensor networks.
Matrix solution of coupling impedance in multi-layer circular cylindrical structures
International Nuclear Information System (INIS)
Continuing interest in computing the coupling impedance of cylindrical multi-layer beam tubes led to several recent publications. A novel matrix method is here presented in which radial wave propagation is treated in analogy to longitudinal transmission lines. Starting from the Maxwell equations the solutions for monopole electromagnetic fields are in each layer described by a 2 x 2 matrix. Assuming isotropic material properties within one layer, the radially transverse field components at the inner boundary of a layer are uniquely determined by matrix transfer of the field components at its outer boundary. By imposing power flow constraints on the matrix, field matching between layers is enforced and replaced by matrix multiplication. The coupling impedance of a stainless steel beam tube defined by a matrix is given as a representative demonstration
Directory of Open Access Journals (Sweden)
Umar Draz
2016-01-01
Full Text Available SMEs (Small and Medium Sized Enterprises sector is facing problems relating to implementation of international quality standards. These SMEs need to identify factors affecting business success abroad for intelligent allocation of resources to the process of internationalization. In this paper, MLP NN (Multi-Layer Perceptron Neural Network has been used for identifying relative importance of key variables related to firm basics, manufacturing, quality inspection labs and level of education in determining the exporting status of Pakistani SMEs. A survey has been conducted for scoring out the pertinent variables in SMEs and coded in MLP NNs. It is found that ?firm registered with OEM (Original Equipment Manufacturer and ?size of firm? are the most important in determining exporting status of SMEs followed by other variables. For internationalization, the results aid policy makers in formulating strategies
International Nuclear Information System (INIS)
SMEs (Small and Medium Sized Enterprises) sector is facing problems relating to implementation of international quality standards. These SMEs need to identify factors affecting business success abroad for intelligent allocation of resources to the process of internationalization. In this paper, MLP NN (Multi-Layer Perceptron Neural Network) has been used for identifying relative importance of key variables related to firm basics, manufacturing, quality inspection labs and level of education in determining the exporting status of Pakistani SMEs. A survey has been conducted for scoring out the pertinent variables in SMEs and coded in MLP NNs. It is found that firm registered with OEM (Original Equipment Manufacturer) and size of firm are the most important in determining exporting status of SMEs followed by other variables. For internationalization, the results aid policy makers in formulating strategies. (author)
Thixoforming of 6066 aluminum alloy by multi-layer spray deposition
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
Two thixoforming technologies of 6066 aluminum alloy (Al-1.37Si-1.37Mg-0.77Cu-0.07Mn) produced by multi-layer spray deposition process were studied. The spray-formed materials are of equiaxed and very fine grain (10～20 μm). And the grain size coarsens slower than that of conventional casting materials at temperature below the liquidus, which may relate to high temperature particles distributed along the grain boundaries. Extrusion and hot pressing were used as the thixoforming processes respectively. After extrusion the materials show a microstructure of mean grain size below 20 μm without obvious recrystallization. The mechanical properties achieved via extrusion and pressing in semi-solid state attain that of common wrought materials with shorter peak aging time of 4～5 h, about half of that in conventional condition.
Novel Intersection Type Recognition for Autonomous Vehicles Using a Multi-Layer Laser Scanner
An, Jhonghyun; Choi, Baehoon; Sim, Kwee-Bo; Kim, Euntai
2016-01-01
There are several types of intersections such as merge-roads, diverge-roads, plus-shape intersections and two types of T-shape junctions in urban roads. When an autonomous vehicle encounters new intersections, it is crucial to recognize the types of intersections for safe navigation. In this paper, a novel intersection type recognition method is proposed for an autonomous vehicle using a multi-layer laser scanner. The proposed method consists of two steps: (1) static local coordinate occupancy grid map (SLOGM) building and (2) intersection classification. In the first step, the SLOGM is built relative to the local coordinate using the dynamic binary Bayes filter. In the second step, the SLOGM is used as an attribute for the classification. The proposed method is applied to a real-world environment and its validity is demonstrated through experimentation. PMID:27447640
Temporal asymmetries in auditory coding and perception reflect multi-layered nonlinearities.
Deneux, Thomas; Kempf, Alexandre; Daret, Aurélie; Ponsot, Emmanuel; Bathellier, Brice
2016-01-01
Sound recognition relies not only on spectral cues, but also on temporal cues, as demonstrated by the profound impact of time reversals on perception of common sounds. To address the coding principles underlying such auditory asymmetries, we recorded a large sample of auditory cortex neurons using two-photon calcium imaging in awake mice, while playing sounds ramping up or down in intensity. We observed clear asymmetries in cortical population responses, including stronger cortical activity for up-ramping sounds, which matches perceptual saliency assessments in mice and previous measures in humans. Analysis of cortical activity patterns revealed that auditory cortex implements a map of spatially clustered neuronal ensembles, detecting specific combinations of spectral and intensity modulation features. Comparing different models, we show that cortical responses result from multi-layered nonlinearities, which, contrary to standard receptive field models of auditory cortex function, build divergent representations of sounds with similar spectral content, but different temporal structure. PMID:27580932
Institute of Scientific and Technical Information of China (English)
M. K. Ghosh; M. Kanoria
2007-01-01
This paper deals with the determination of the thermo-elastic displacements and stresses in a multi-layered body set up in different layers of different thickness having different elastic properties due to the application of heat and a concentrated load in the uppermost surface of the medium. Each layer is assumed to be made of homogeneous and isotropic elastic material. The relevant displacement components for each layer are taken to be axisymmetric about a line, which is perpendicular to the plane surfaces of all layers. The stress function for each layer, therefore, satisfies a single equation in absence of any body forces. The equation is then solved by integral transform technique. Analytical expressions for thermo-elastic displacements and stresses in the underlying mass and the corresponding numerical codes are constructed for any number of layers. However, the numerical comparison is made for three and four layers.
Dynamic analysis of multi layer foundation of steam turbines in nuclear power plants
International Nuclear Information System (INIS)
In this work, the coupled Rotor-pedestal-foundation motion is modeled and formulated. Transfer matrix method is implemented in the modeling. The model is adequate for multi layer foundation systems of steam turbines in nuclear power plants. The rotor modeled used is distributed mass model. Bearings are modeled with eight stiffness and damping coefficients and pedestals by mass, stiffness and damping property. Foundation is modeled with distributed mass and stiffness properties in which properties in vertical and horizontal direction may be different. The model is examined using analytical results and good agreement is achieved. Results of the coupled modeling indicate less error in comparison with previous separate modeling and lumped-mass methods
Highly accurate thickness measurement of multi-layered automotive paints using terahertz technology
Krimi, Soufiene; Klier, Jens; Jonuscheit, Joachim; von Freymann, Georg; Urbansky, Ralph; Beigang, René
2016-07-01
In this contribution, we present a highly accurate approach for thickness measurements of multi-layered automotive paints using terahertz time domain spectroscopy in reflection geometry. The proposed method combines the benefits of a model-based material parameters extraction method to calibrate the paint coatings, a generalized Rouard's method to simulate the terahertz radiation behavior within arbitrary thin films, and the robustness of a powerful evolutionary optimization algorithm to increase the sensitivity of the minimum thickness measurement limit. Within the framework of this work, a self-calibration model is introduced, which takes into consideration the real industrial challenges such as the effect of wet-on-wet spray in the painting process.
Accelerating decomposition of light field video for compressive multi-layer display.
Cao, Xuan; Geng, Zheng; Li, Tuotuo; Zhang, Mei; Zhang, Zhaoxing
2015-12-28
Compressive light field display based on multi-layer LCDs is becoming a popular solution for 3D display. Decomposing light field into layer images is the most challenging task. Iterative algorithm is an effective solver for this high-dimensional decomposition problem. Existing algorithms, however, iterate from random initial values. As such, significant computation time is required due to the deviation between random initial estimate and target values. Real-time 3D display at video rate is difficult based on existing algorithms. In this paper, we present a new algorithm to provide better initial values and accelerate decomposition of light field video. We utilize internal coherence of single light field frame to transfer the ignorance-to-target to a much lower resolution level. In addition, we explored external coherence for further accelerating light field video and achieved 5.91 times speed improvement. We built a prototype and developed parallel algorithm based on CUDA. PMID:26832058
New Metaphors and Multi Layered in Khaqani´s Poem
Directory of Open Access Journals (Sweden)
Mohammadamir Mashhadi
2011-02-01
Full Text Available Abstract Metaphor is the most important transmission device language than true application to figurative application, It plays a role more than other poetic elements in new creation and forming Personal Style. Khaqani is a creator of new metaphor in number and the most creative power speaking persian. He used artistic creation and hard to obtain in making poem. He profits of new and rare metaphors. Comprehension the metaphors of Kaqani ´ s Poem results to Underestanding his creation in Imaginary and his Poem. This article with this aim is studing background metaphor creation in Kaqani ´ s poem and his modernity new relation and similarity between objects and phenomenons that cause making new metaphor. Sometime his discovery relation between two objects formed in several relation layer that could call them Multi layered metaphor.
Highly Accurate Multi-layer Perceptron Neural Network for Air Data System
Directory of Open Access Journals (Sweden)
H. S. Krishna
2009-11-01
Full Text Available The error backpropagation multi-layer perceptron algorithm is revisited. This algorithm is used to train and validate two models of three-layer neural networks that can be used to calibrate a 5-hole pressure probe. This paper addresses Occam's Razor problem as it describes the adhoc training methodology applied to improve accuracy and sensitivity. The trained outputs from 5-4-3 feed-forward network architecture with jump connection are comparable to second decimal digit (~0.05 accuracy, hitherto unreported in literature.Defence Science Journal, 2009, 59(6, pp.670-674, DOI:http://dx.doi.org/10.14429/dsj.59.1574
A Multi-layer, Hierarchical Information Management System for the Smart Grid
Energy Technology Data Exchange (ETDEWEB)
Lu, Ning; Du, Pengwei; Paulson, Patrick R.; Greitzer, Frank L.; Guo, Xinxin; Hadley, Mark D.
2011-10-10
This paper presents the modeling approach, methodologies, and initial results of setting up a multi-layer, hierarchical information management system (IMS) for the smart grid. The IMS allows its users to analyze the data collected by multiple control and communication networks to characterize the states of the smart grid. Abnormal, corrupted, or erroneous measurement data and outliers are detected and analyzed to identify whether they are caused by random equipment failures, unintentional human errors, or deliberate tempering attempts. Data collected from different information networks are crosschecked for data integrity based on redundancy, dependency, correlation, or cross-correlations, which reveal the interdependency between data sets. A hierarchically structured reasoning mechanism is used to rank possible causes of an event to aid the system operators to proactively respond or provide mitigation recommendations to remove or neutralize the threats. The model provides satisfactory performance on identifying the cause of an event and significantly reduces the need of processing myriads of data collected.
Reference Architecture for Multi-Layer Software Defined Optical Data Center Networks
Directory of Open Access Journals (Sweden)
Casimer DeCusatis
2015-09-01
Full Text Available As cloud computing data centers grow larger and networking devices proliferate; many complex issues arise in the network management architecture. We propose a framework for multi-layer; multi-vendor optical network management using open standards-based software defined networking (SDN. Experimental results are demonstrated in a test bed consisting of three data centers interconnected by a 125 km metropolitan area network; running OpenStack with KVM and VMW are components. Use cases include inter-data center connectivity via a packet-optical metropolitan area network; intra-data center connectivity using an optical mesh network; and SDN coordination of networking equipment within and between multiple data centers. We create and demonstrate original software to implement virtual network slicing and affinity policy-as-a-service offerings. Enhancements to synchronous storage backup; cloud exchanges; and Fibre Channel over Ethernet topologies are also discussed.
Recognition of Epileptiform Patterns in the Human Electroencephalogram Using Multi-Layer Perceptron
Directory of Open Access Journals (Sweden)
V. Mokran
1995-06-01
Full Text Available Automatic detection of epileptiform patterns is highly desirable during continuous monitoring of patients with epilepsy. This paper describes an unconvential system for automatic off-line recognition of epileptic sharp transients in the human electroencephalogram (EEG, based on a standard neural network architecture - multi-layer perceptron (MLP, and implemented on a Silicon Graphics Indigo workstation. The system makes comprehensive use of wide spatial contextual information available on 12 channels of EEG and takes advantage of discrete dyadic wavelet transform (DDWT for efficient parameterisation of EEG data. The EEG database consists of 12 patients, 7 of which are used in the process of training of MLP. The resulting MLP is presented with the testing data set consisting of all data vectors from all 12 patients, and is shown to be capable to recognise a wide variety of epileptic signals.
Field theoretical model of multi-layered Josephson junction and dynamics of Josephson vortices
Fujimori, Toshiaki; Nitta, Muneto
2016-01-01
Multi-layered Josephson junctions are modeled in the context of a field theory, and dynamics of Josephson vortices trapped inside insulators are studied. Starting from a theory consisting of complex and real scalar fields coupled to a U(1) gauge field which admit parallel $N-1$ domain-wall solutions, Josephson couplings are introduced weakly between the complex scalar fields. The $N-1$ domain walls behave as insulators separating $N$ superconductors. We construct the effective Lagrangian on the domain walls, which reduces to a coupled sine-Gordon model for well-separated walls and contains more interactions for walls at short distance. We then construct sine-Gordon solitons emerging in the effective theory that we identify Josephson vortices carrying singly quantized magnetic fluxes. When two neighboring superconductors tend to have the same phase, the ground state does not change with the positions of domain walls. On the other hand, when two neighboring superconductors tend to have the $\\pi$ phase differenc...
Matrix solution of coupling impedance in multi-layer circular cyclindrical structures
Energy Technology Data Exchange (ETDEWEB)
Hahn,H.; Choi, E.
2009-05-04
Continuing interest in computing the coupling impedance of cylindrical multi-layer beam tubes led to several recent publications. A novel matrix method is here presented in which radial wave propagation is treated in analogy to longitudinal transmission lines. Starting from the Maxwell equations the solutions for monopole electromagnetic fields are in each layer described by a 2 x 2 matrix. Assuming isotropic material properties within one layer, the radially transverse field components at the inner boundary of a layer are uniquely determined by matrix transfer of the field components at its outer boundary. By imposing power flow constraints on the matrix, field matching between layers is enforced and replaced by matrix multiplication. The coupling impedance of a stainless steel beam tube defined by a matrix is given as a representative demonstration.
A New Approach to Predicting Bankruptcy: Combining DEA and Multi-Layer Perceptron
Directory of Open Access Journals (Sweden)
Ayan Mukhopadhyay
2012-07-01
Full Text Available The question of financial health and sustenance of a firm is so intriguing that it has spanned numerous studies. For investors,stakeholders and lenders, assessing the risk associated with an enterprise is vital. Several tools have been formulated to deal with predicting the solvency of a firm. This paper attempts to combine Data Envelopment Analysis and Multi-Layer Perceptron (MLP to suggest a new method for prediction of bankruptcy that not only focusses on historical financial data of firms that filed for bankruptcy like other past studies but also takes into account the data of those firms that were likely to do so. This method thus identifies firms that have a high chance of facing bankruptcy along with those that have filed for bankruptcy. The performance of this procedure is compared with MLP. The suggested method outperforms MLP in prediction of bankruptcy.
Makino, Sho; Yamamoto, Rie; Sugimoto, Shigeyuki; Sugimoto, Wataru
2016-09-01
Water-stable multi-layered lithium-doped carbon (LixC6) negative electrode using poly(ethylene oxide) (PEO)-lithium bis(trifluoromethansulfonyl)imide (LiTFSI) polymer electrolyte containing N-methyl-N-propylpiperidinium bis(trifluoromethansulfonyl)imide (PP13TFSI) ionic liquid was developed. Electrochemical properties at 60 °C of the aqueous hybrid supercapacitor using activated carbon positive electrode and a multi-layered LixC6 negative electrode (LixC6 | PEO-LiTFSI | LTAP) without PP13TFSI exhibited performance similar to that using Li anode (Li | PEO-LiTFSI | LTAP). A drastic decrease in ESR was achieved by the addition of PP13TFSI to PEO-LiTFSI, allowing room temperature operation. The ESR of the multi-layered LixC6 negative electrode with PEO-LiTFSI-PP13TFSI at 25 °C was 801 Ω cm2, which is 1/6 the value of the multi-layered Li negative electrode with PEO-LiTFSI (5014 Ω cm2). Charge/discharge test of the aqueous hybrid supercapacitor using multi-layered LixC6 negative electrode with PEO-LiTFSI-PP13TFSI at 25 °C afforded specific capacity of 20.6 mAh (g-activated carbon)-1 with a working voltage of 2.7-3.7 V, and good long-term capability up to 3000 cycles. Furthermore, an aqueous hybrid supercapacitor consisting of a high capacitance RuO2 nanosheet positive electrode and multi-layered LixC6 negative electrode with PEO-LiTFSI-PP13TFSI showed specific capacity of 196 mAh (g-RuO2)-1 and specific energy of 625 Wh (kg-RuO2)-1 in 2.0 M acetic acid-lithium acetate buffered solution at 25 °C.
The Integration of Ecological processes into a Multi-layer Higher order closure Land Surface Model
Chang, K. Y.; Paw U, K. T.; Chen, S. H.
2015-12-01
The ecological impacts on biogeophysical and biogeochemical processes were investigated by a series of simulations conducted by a multi-layer higher order closure land surface model (UCD-ACASA) driven by a variety of meteorological and ecological conditions. The results show that the implementation of a more realistic ecological dataset, once carefully quality controlled, can significantly improve the biogeophysical and biogeochemical simulations, which suggests that the ecological impacts on surface layer simulations are as important as the reliability of the selected land surface model. Therefore, the ability to simulate realistic ecological conditions is imperative and beneficial to improve weather and climate simulations. We coupled the ecological processes in UCD-ACASA by adapting the fully prognostic plant carbon and nitrogen dynamics from the version 4.5 of the Community Land Model (CLM4.5). The simulated ecological conditions are sensitive to both radiative transfer processes and leaf distribution inside the canopy, and the multi-layer feature built in UCD-ACASA enables it to describe these properties more realistically as compared to the other big-leaf models. We conducted another set of simulations to examine the reliability of the simulated biogeophysical, biogeochemical and ecological results. The simulated Leaf Area Index (LAI) was compared with a high resolution remotely sensed LAI dataset, and the results show that the simulated LAI tends to overestimate mean LAI and underestimate annual LAI variation at the selected sites. However, the simulated LAI is reasonable enough to produce comparable simulation results against the simulations driven directly by remotely sensed LAI for the tested biogeophysical and biogeochemical fluxes. The results show that ecological impacts on biogeophysical and biogeochemical simulations are significant, and the implementation of biogeochemical processes into a land surface model has the potential to improve weather and
International Nuclear Information System (INIS)
We report on the computational design, fabrication and validation of a multi-layer silicon based thin film solar cell. The cell structure consists of a thin absorber layer of amorphous silicon deposited on a back-reflector aluminum layer and coated on top with ITO transparent conductive oxide. The structure is mounted on a glass substrate. We first use constrained optimization techniques along with numerical solvers of the electromagnetic equations (i.e. FDTD) to tune the geometry of the design. The resulting structure suggests that photon absorptivity in the thin film silicon can be enhanced by as much as 100% over the uncoated layer. The proposed design is then fabricated using thin film deposition techniques, along with a control sample of bare silicon absorber for comparison. AFM imaging and spectrophotometry experiments are applied to image and record the surface roughness and measure the reflectivity spectrum of the sample. Using the measured reflectivity spectrum, we then use inverse optimization to estimate the realized thin film dimensions, deposition error and unwanted oxidation volume. At the end, we use a statistical Monte Carlo analysis as a second method of verification to demonstrate that the measured spectra are in accordance with the expected curves from simulation, and to estimate the effects of fabrication error. - Highlights: • Design, fabrication and validation of multi-layer silicon solar cell are studied. • The cell consists of aluminum, amorphous silicon and ITO layers. • The proposed designs are fabricated by deposition techniques. • Inverse optimization is used to estimate the realized dimensions and errors
Interfacial characteristics of polyethylene terephthalate-based piezoelectric multi-layer films
Energy Technology Data Exchange (ETDEWEB)
Liu, Z.H. [Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan (China); Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, National Science Council Core Facilities Laboratory for Nano-Science and Nano-Technology in Kaohsiung-Pingtung area, Taiwan (China); Electronics and Optoelectronics Research Laboratories, Industrial Technology Research Institute, Hsinchu 310, Taiwan (China); Pan, C.T., E-mail: panct@mail.nsysu.edu.tw [Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan (China); Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, National Science Council Core Facilities Laboratory for Nano-Science and Nano-Technology in Kaohsiung-Pingtung area, Taiwan (China); Chen, Y.C. [Department of Electrical Engineering, National Sun Yat-Sen University, Kaohsiung 804, Taiwan (China); Liang, P.H. [Department of Mechanical and Electro-Mechanical Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan (China)
2013-03-01
The study examines the deformation between interfaces and the adhesion mechanism of multi-layer flexible electronic composites. Indium tin oxide (ITO), aluminum (Al), and zinc oxide (ZnO) were deposited on a polyethylene terephthalate (PET) substrate using radio frequency magnetron sputtering at room temperature to form flexible structures (e.g., ITO/PET, Al/PET, ZnO/ITO/PET, and ZnO/Al/PET) for piezoelectric transducers. ITO and Al films are used as the conductive layers. A ZnO thin film shows a high (002) c-axis preferred orientation at 2θ = 34.45° and excellent piezoelectric properties. Nanoscratching and nano-indention testing were conducted to analyze the adhesion following periodic mechanical stress. Additionally, two Berkovich and conical probes with a curvature radius of 40 nm and 10 μm are examined for the scratching test. A 4-point probe is used to measure the conductive properties. The plastic deformation between the ductile Al film and PET substrate is observed using scanning electron microscopy to examine the chip formation on the ITO/PET. Delamination between the ZnO and Al/PET substrate was not observed. The result suggests that ZnO film has excellent adhesion with Al/PET compared to ITO/PET. - Highlights: ► Interfaces and adhesion mechanism of multi-layer flexible electronic composites ► Polyethylene terephthalate (PET) based flexible structures ► Nano-scratching and nano-indention tests were used to analyze adhesion. ► Using two various probes of Berkovich and conical ► Piezoelectric zinc oxide film has excellent adhesion with aluminum/PET.
Interfacial characteristics of polyethylene terephthalate-based piezoelectric multi-layer films
International Nuclear Information System (INIS)
The study examines the deformation between interfaces and the adhesion mechanism of multi-layer flexible electronic composites. Indium tin oxide (ITO), aluminum (Al), and zinc oxide (ZnO) were deposited on a polyethylene terephthalate (PET) substrate using radio frequency magnetron sputtering at room temperature to form flexible structures (e.g., ITO/PET, Al/PET, ZnO/ITO/PET, and ZnO/Al/PET) for piezoelectric transducers. ITO and Al films are used as the conductive layers. A ZnO thin film shows a high (002) c-axis preferred orientation at 2θ = 34.45° and excellent piezoelectric properties. Nanoscratching and nano-indention testing were conducted to analyze the adhesion following periodic mechanical stress. Additionally, two Berkovich and conical probes with a curvature radius of 40 nm and 10 μm are examined for the scratching test. A 4-point probe is used to measure the conductive properties. The plastic deformation between the ductile Al film and PET substrate is observed using scanning electron microscopy to examine the chip formation on the ITO/PET. Delamination between the ZnO and Al/PET substrate was not observed. The result suggests that ZnO film has excellent adhesion with Al/PET compared to ITO/PET. - Highlights: ► Interfaces and adhesion mechanism of multi-layer flexible electronic composites ► Polyethylene terephthalate (PET) based flexible structures ► Nano-scratching and nano-indention tests were used to analyze adhesion. ► Using two various probes of Berkovich and conical ► Piezoelectric zinc oxide film has excellent adhesion with aluminum/PET
Institute of Scientific and Technical Information of China (English)
JunJun Yang; ZhiBin He; WeiJun Zhao; Jun Du; LongFei Chen; Xi Zhu
2016-01-01
Soil moisture simulation and prediction in semi-arid regions are important for agricultural production, soil conservation and climate change. However, considerable heterogeneity in the spatial distribution of soil moisture, and poor ability of distributed hydrological models to estimate it, severely impact the use of soil moisture models in research and practical applications. In this study, a newly-developed technique of coupled (WA-ANN) wavelet analysis (WA) and artificial neural network (ANN) was applied for a multi-layer soil moisture simulation in the Pailugou catchment of the Qilian Mountains, Gansu Province, China. Datasets included seven meteorological factors: air and land surface temperatures, relative humidity, global radiation, atmospheric pressure, wind speed, precipitation, and soil water content at 20, 40, 60, 80, 120 and 160 cm. To investigate the effectiveness of WA-ANN, ANN was applied by itself to conduct a comparison. Three main findings of this study were: (1) ANN and WA-ANN provided a statistically reliable and robust prediction of soil moisture in both the root zone and deepest soil layer studied (NSE >0.85, NSE means Nash-Sutcliffe Efficiency coefficient); (2) when input meteorological factors were transformed using maximum signal to noise ratio (SNR) and one-dimensional auto de-noising algorithm (heursure) in WA, the coupling technique improved the performance of ANN especially for soil moisture at 160 cm depth; (3) the results of multi-layer soil moisture prediction indicated that there may be different sources of water at different soil layers, and this can be used as an indicator of the maximum impact depth of meteorological factors on the soil water content at this study site. We conclude that our results show that appropriate simulation methodology can provide optimal simulation with a minimum distortion of the raw-time series; the new method used here is applicable to soil sciences and management applications.
Snow instability evaluation: calculating the skier-induced stress in a multi-layered snowpack
Monti, Fabiano; Gaume, Johan; van Herwijnen, Alec; Schweizer, Jürg
2016-03-01
The process of dry-snow slab avalanche formation can be divided into two phases: failure initiation and crack propagation. Several approaches tried to quantify slab avalanche release probability in terms of failure initiation based on shear stress and strength. Though it is known that both the properties of the weak layer and the slab play a major role in avalanche release, most previous approaches only considered slab properties in terms of slab depth, average density and skier penetration. For example, for the skier stability index, the additional stress (e.g. due to a skier) at the depth of the weak layer is calculated by assuming that the snow cover can be considered a semi-infinite, elastic, half-space. We suggest a new approach based on a simplification of the multi-layered elasticity theory in order to easily compute the additional stress due to a skier at the depth of the weak layer, taking into account the layering of the snow slab and the substratum. We first tested the proposed approach on simplified snow profiles, then on manually observed snow profiles including a stability test and, finally, on simulated snow profiles. Our simple approach reproduced the additional stress obtained by finite element simulations for the simplified profiles well - except that the sequence of layering in the slab cannot be replicated. Once implemented into the classical skier stability index and applied to manually observed snow profiles classified into different stability classes, the classification accuracy improved with the new approach. Finally, we implemented the refined skier stability index into the 1-D snow cover model SNOWPACK. The two study cases presented in this paper showed promising results even though further verification is still needed. In the future, we intend to implement the proposed approach for describing skier-induced stress within a multi-layered snowpack into more complex models which take into account not only failure initiation but also crack
Investigation on the Thermal Conductivity of 3-Dimensional and 4-Directional Braided Composites
Institute of Scientific and Technical Information of China (English)
Liu Zhenguo; Zhang Haiguo; Lu Zixing; Li Diansen
2007-01-01
It is vital to choose a factual and reasonable micro-structural model of braided composites for improving the calculating precision of thermal property of 3-D braided composites by finite element method (FEM). On the basis of new microstructure model of braided composites proposed recently, the model of FEM calculation for thermal conductivity of 3-dimennsional and 4-directional braided composites is set up in this paper. The curves of coefficient of effective thermal conductivity versus fiber volume ratio and interior braiding angle are obtained. Furthermore, comparing the results of FEM with the available experimental data, the reasonability and veracity of calculation are confirmed at the same time.
Relationship Between Compression Strength and Its Microstructure of 5 Axial-Braided Composite
Institute of Scientific and Technical Information of China (English)
Yang; Chaokun; Zhu; Jianxun; Jiang; Yun
2007-01-01
Compression performance of 5-axial braided composites is observed through compression tests.A mixed model of micro-buckling shear with braided tows web is set up to predict compression stress of braided composite through analyzing three broken modes.Using this mixed model,data from tests indicated that the main parameters effecting the compression properties of braided composite are fiber volume fraction,directional angle,axial-tow volume fraction and diameter of tow.Contributing rate of tows is proposed to describe the compression properties of fibre composites.Optimization geometrical structure of braids can optimize composite properties.
Processing and performance of nanophased braided carbon/epoxy composites
International Nuclear Information System (INIS)
A systematic study has been carried out to investigate mechanical properties of 2D nanophased braided carbon/epoxy composites. SC-15 epoxy with three types of braided fabrics: ±45 deg., 0/±45 deg., and 0/±60 deg. was used to fabricate composite laminates using vacuum assisted resin infusion molding (VARIM) process. Low-velocity impact (LVI), ultrasonic nondestructive evaluation (NDE) and 3-point bend flexure studies were carried out on biaxial and triaxial braided samples. Impact parameters like peak load and absorbed energy were calculated. All the LVI tested samples were then subjected to ultrasonic c-scan testing to determine the damage size. From the results it was seen that laminates sustained the impact load without any damage at 10 J, a little damage at 20 J and more damage at 30 J. From the ultrasonic tests it was seen that the biaxial ±45 deg. laminates had lowest damage. Flexural test showed the highest flexural strength and stiffness for triaxial 0 deg./±45 deg. An investigation was also carried out to improve the properties of the braided laminates by introducing Nanomer I-28E nanoclay, a surface modified montmorillonite mineral, into SC-15 epoxy matrix. Different weight percentages of nanoclay were dispersed in SC-15 epoxy. Highest properties were obtained for samples with 1% by weight of nanoclay reinforcement.
Processing and performance of nanophased braided carbon/epoxy composites
Energy Technology Data Exchange (ETDEWEB)
Hosur, Mahesh V., E-mail: hosur@tuskegee.ed [Center for Advanced Materials, Tuskegee University, Tuskegee, AL 36088 (United States); Islam, Md. Mazedul; Jeelani, Shaik [Center for Advanced Materials, Tuskegee University, Tuskegee, AL 36088 (United States)
2010-04-15
A systematic study has been carried out to investigate mechanical properties of 2D nanophased braided carbon/epoxy composites. SC-15 epoxy with three types of braided fabrics: +-45 deg., 0/+-45 deg., and 0/+-60 deg. was used to fabricate composite laminates using vacuum assisted resin infusion molding (VARIM) process. Low-velocity impact (LVI), ultrasonic nondestructive evaluation (NDE) and 3-point bend flexure studies were carried out on biaxial and triaxial braided samples. Impact parameters like peak load and absorbed energy were calculated. All the LVI tested samples were then subjected to ultrasonic c-scan testing to determine the damage size. From the results it was seen that laminates sustained the impact load without any damage at 10 J, a little damage at 20 J and more damage at 30 J. From the ultrasonic tests it was seen that the biaxial +-45 deg. laminates had lowest damage. Flexural test showed the highest flexural strength and stiffness for triaxial 0 deg./+-45 deg. An investigation was also carried out to improve the properties of the braided laminates by introducing Nanomer I-28E nanoclay, a surface modified montmorillonite mineral, into SC-15 epoxy matrix. Different weight percentages of nanoclay were dispersed in SC-15 epoxy. Highest properties were obtained for samples with 1% by weight of nanoclay reinforcement.
Higher dimensional unitary braid matrices: Construction, associated structures and entanglements
International Nuclear Information System (INIS)
We construct (2n)2 x (2n)2 unitary braid matrices R-circumflex for n ≥ 2 generalizing the class known for n = 1. A set of (2n) x (2n) matrices (I, J,K,L) are defined. R-circumflex is expressed in terms of their tensor products (such as K x J), leading to a canonical formulation for all n. Complex projectors P± provide a basis for our real, unitary R-circumflex. Baxterization is obtained. Diagonalizations and block- diagonalizations are presented. The loss of braid property when R-circumflex (n > 1) is block-diagonalized in terms of R-circumflex (n = 1) is pointed out and explained. For odd dimension (2n + 1)2 x (2n + 1)2, a previously constructed braid matrix is complexified to obtain unitarity. R-circumflexLL- and R-circumflexTT- algebras, chain Hamiltonians, potentials for factorizable S-matrices, complex non-commutative spaces are all studied briefly in the context of our unitary braid matrices. Turaev construction of link invariants is formulated for our case. We conclude with comments concerning entanglements. (author)
Nonlinear Deformation Behavior of New Braided Composites with Six-axis Yarn Orientations
International Nuclear Information System (INIS)
The braiding technology is one of fabrication methods that can produce three-dimensional fiber preforms. Braided composites have many advantages over other two-dimensional composites such as no delamination, high impact and fatigue properties, near-net shape preform, etc. Due to the undulated yarns in the braided preforms, however, their axial stiffness is lower than that of uni-directional or woven composites. To improve the axial stiffness, the longitudinal axial yarns were already introduced along with the braiding axis (five-axis braiding technology). In this study, we developed a new braided structure using six-axis braiding technology. In addition to braiding and longitudinal axial yarns, transverse axial yarn was introduced. New braided composites, so called six-axis braiding composites, were manufactured using ultra high molecular weight polyethylene and epoxy resin and their mechanical properties were characterized. To investigate the mechanical performance of these braided composites according to their manufacturing conditions, a numerical analysis was performed using their unit-cell modeling and finite element analysis. In the analysis the nonlinear deformation behavior will be included.
Directory of Open Access Journals (Sweden)
Yusuke Sakai
Full Text Available Cell sheet engineering is attracting attention from investigators in various fields, from basic research scientists to clinicians focused on regenerative medicine. However, hepatocytes have a limited proliferation potential in vitro, and it generally takes a several days to form a sheet morphology and multi-layered sheets. We herein report our rapid and efficient technique for generating multi-layered human hepatic cell (HepaRG® cell sheets using pre-cultured fibroblast monolayers derived from human skin (TIG-118 cells as a feeder layer on a temperature-responsive culture dish. Multi-layered TIG-118/HepaRG cell sheets with a thick morphology were harvested on day 4 of culturing HepaRG cells by forceful contraction of the TIG-118 cells, and the resulting sheet could be easily handled. In addition, the human albumin and alpha 1-antitrypsin synthesis activities of TIG-118/HepaRG cells were approximately 1.2 and 1.3 times higher than those of HepaRG cells, respectively. Therefore, this technique is considered to be a promising modality for rapidly fabricating multi-layered human hepatocyte sheets from cells with limited proliferation potential, and the engineered cell sheet could be used for cell transplantation with highly specific functions.
Energy Technology Data Exchange (ETDEWEB)
Tsukamoto, Hideaki, E-mail: tsukamoto.hideaki@nitech.ac.jp
2015-08-15
Highlights: • Multi-layered graded structures are possibly used for a new type of crash boxes in automobiles. • 2- and 6-layered aluminum (A1050)/duralumin (A2017) graded structures were fabricated by hot rolling. • Hardness varies around the interface between aluminum and duralumin in heat-treated samples with gradient distribution of Cu. • Macroscopic mechanical property gradient is effective to make superior crash boxes. • The deep-drawn cups with 6-layered structures show superior impact compressive properties. - Abstract: This study aims to investigate impact compressive behavior of deep-drawn cups consisting of aluminum (A1050)/duralumin (A2017) multi-layered structures, which are fabricated by hot rolling. Such multi-layered structures are possibly used for a new type of crash boxes in automobiles to effectively absorb impact energy. The effect of heat treatments on micro-Vickers hardness gradients at the interfaces between layers in 2 and 6-layered aluminum/duralumin structures have been investigated. Impact compressive behavior of deep-drawn cups consisting of such aluminum/duralumin multi-layered graded structures has been studied in terms of energy absorption, maximum force and maximum displacement with examination based on micro-Vickers hardness results. Deep-drawn cups consisting of 6-layerd clad structures with gradient properties exhibited superior impact compressive characteristics to be effective in application to vehicle crash absorbers.
DEFF Research Database (Denmark)
Andersen, Thomas Lykke; Skals, K. T.; Burcharth, Hans F.
2009-01-01
A model test study was conducted to study overtopping and front slope stability of homogenous and multi-layered berm breakwaters. The two breakwater types are compared and cons and pros are listed. The study shows that the optimum number of stone classes might be significantly lower than what has...
International Nuclear Information System (INIS)
Highlights: • Multi-layered graded structures are possibly used for a new type of crash boxes in automobiles. • 2- and 6-layered aluminum (A1050)/duralumin (A2017) graded structures were fabricated by hot rolling. • Hardness varies around the interface between aluminum and duralumin in heat-treated samples with gradient distribution of Cu. • Macroscopic mechanical property gradient is effective to make superior crash boxes. • The deep-drawn cups with 6-layered structures show superior impact compressive properties. - Abstract: This study aims to investigate impact compressive behavior of deep-drawn cups consisting of aluminum (A1050)/duralumin (A2017) multi-layered structures, which are fabricated by hot rolling. Such multi-layered structures are possibly used for a new type of crash boxes in automobiles to effectively absorb impact energy. The effect of heat treatments on micro-Vickers hardness gradients at the interfaces between layers in 2 and 6-layered aluminum/duralumin structures have been investigated. Impact compressive behavior of deep-drawn cups consisting of such aluminum/duralumin multi-layered graded structures has been studied in terms of energy absorption, maximum force and maximum displacement with examination based on micro-Vickers hardness results. Deep-drawn cups consisting of 6-layerd clad structures with gradient properties exhibited superior impact compressive characteristics to be effective in application to vehicle crash absorbers
Xia, Wenjie; Ruiz, Luis; Pugno, Nicola M.; Keten, Sinan
2016-03-01
Multi-layer graphene assemblies (MLGs) or fibers with a staggered architecture exhibit high toughness and failure strain that surpass those of the constituent single sheets. However, how the architectural parameters such as the sheet overlap length affect these mechanical properties remains unknown due in part to the limitations of mechanical continuum models. By exploring the mechanics of MLG assemblies under tensile deformation using our established coarse-grained molecular modeling framework, we have identified three different critical interlayer overlap lengths controlling the strength, plastic stress, and toughness of MLGs, respectively. The shortest critical length scale Lsc governs the strength of the assembly as predicted by the shear-lag model. The intermediate critical length Lpc is associated with a dynamic frictional process that governs the strain localization propensity of the assembly, and hence the failure strain. The largest critical length scale LTc corresponds to the overlap length necessary to achieve 90% of the maximum theoretical toughness of the material. Our analyses provide the general guidelines for tuning the constitutive properties and toughness of multilayer 2D nanomaterials using elasticity, interlayer adhesion energy and geometry as molecular design parameters.Multi-layer graphene assemblies (MLGs) or fibers with a staggered architecture exhibit high toughness and failure strain that surpass those of the constituent single sheets. However, how the architectural parameters such as the sheet overlap length affect these mechanical properties remains unknown due in part to the limitations of mechanical continuum models. By exploring the mechanics of MLG assemblies under tensile deformation using our established coarse-grained molecular modeling framework, we have identified three different critical interlayer overlap lengths controlling the strength, plastic stress, and toughness of MLGs, respectively. The shortest critical length scale
Heating of multi-layered samples by a Nd: YAG pulsed laser
Directory of Open Access Journals (Sweden)
Diniz Neto, O. O.
1998-04-01
Full Text Available In the work we examine the heating of multi-layered samples by a powerful Nd - YAG pulsed láser. The samples are made of two and three layers, conductor-isolator (Al-Al_{2}O_{3}, conductor-conductor (Al-Ag; Al-Au and conductor-conductor-conductor (Al-Au-Ag; Ag-Au-Al. The transient behaviour of the temperature distribution throughout the sample is computed. We carry out three dimensional model calculations for the heating process in which we consider not only the temperature dependence of the sample thermal and optical parameters but also the space and time characteristics of the laser beam as the heating source. We showed the influence of the substrate in the thermal profile, in space and time, and máximum temperature on the multi-layered samples.
Em nosso trabalho examinamos o aquecimento de amostras compostas de duas e três camadas, condutor- isolante e condutor-condutor, com um pulso potente de láser. O comportamento transiente da distribuição de temperatura através da amostra foi calculado. Em nosso modelo de calculo para o processo de aquecimento levamos em conta a dependência com a temperatura dos parâmetros térmicos (difusividade, capacidade e condutividade térmica, óticos (refletividade e coeficiente de absorção, bem como a dependência das condições de contorno com o tempo e consequentemente com a temperatura. Aplicamos nossa metodología para calcular o aquecimento amostras compostas: Al-Au, Al-Ag, Al-Al_{2}O_{3}, Al-Au-Ag e Ag-Au-Al. Concluimos que o substrato influencia as temperaturas máximas nas superfície exposta ao láser e a forma com que a frente de calor se propaga nas amostras termicamente finas.
A multi-layer description of Reynolds stresses in canonical wall bounded flows
Chen, Xi; Hussain, Fazle; She, Zhen-Su
2015-11-01
A complete description of the Reynolds stress tensor is obtained for all three canonical wall turbulence (channel, pipe and turbulent boundary layer - TBL). The result builds on a multi-layer description of length (order) functions and their ratios, including viscous sublayer, buffer layer, meso-layer for the near wall (inner) region, and bulk flow or a central core (absent in TBL) for the outer region. It is shown that the streamwise mean kinetic-energy profile is quantified with high accuracy over the entire flow domain. The model contains only three Re-dependent parameters for Reynolds number (Re) covering nearly three decades. Furthermore, the inner peak location is predicted to be invariant at y+ = 15, while its magnitude shows notable Re and geometry effects, predicted to be .9.2 for high Re's pipe flows. A mechanism is proposed for the emergence of outer peak in pipes, whose magnitude is predicted to scale as .Reτ0. 05 beyond a critical Reτ about 104(). The recently reported logarithmic dependence in the bulk is recovered, but with an alternative explanation. The result is successfully extended to TBL flows by a fractional total stress and an absence of core. Equally accurate descriptions of vertical and spanwise kinetic-energy are also presented for the three flows. The result has been used to modify turbulent engineering models (i.e. k- ω model) with significant improvement.
Ganglion-Based Balance Design of Multi-Layer Model and Its Watchfulness-Keeping
Institute of Scientific and Technical Information of China (English)
Hui Wei; Shang-Min Luan
2005-01-01
An important problem of machine vision is the balance among the efficiency, accuracy and computation cost.The visual system of man can keep watchfulness to the perimeter of a visual field and subtly process information emerging in the center of the visual field at the same time. This kind of requirement assignment of computation can virtually ease the demand of hardware both in quantity and complexity. Therefore designing an artificial model based on biological mechanism is an effective approach. In this paper a multi-layer neural model is designed based on the multi-scale receptive fields of ganglions in retina. The model can keep watch on the periphery part of a scene while processing the center information of the scene. And why it can balance the hardware complexity, processing precision and computational intensity is analyzed.An experiment is done to test the model's sensitivity in watchfulness keeping and its efficiency and veracity in environment sampling. This model may provide valuable inspiration in the implementation of real-time processing and the avoidance of expensive computation cost in machine vision.
Discriminative Learning for Automatic Staging of Placental Maturity via Multi-layer Fisher Vector
Lei, Baiying; Yao, Yuan; Chen, Siping; Li, Shengli; Li, Wanjun; Ni, Dong; Wang, Tianfu
2015-07-01
Currently, placental maturity is performed using subjective evaluation, which can be unreliable as it is highly dependent on the observations and experiences of clinicians. To address this problem, this paper proposes a method to automatically stage placenta maturity from B-mode ultrasound (US) images based on dense sampling and novel feature descriptors. Specifically, our proposed method first densely extracts features with a regular grid based on dense sampling instead of a few unreliable interest points. Followed by, these features are clustered using generative Gaussian mixture model (GMM) to obtain high order statistics of the features. The clustering representatives (i.e., cluster means) are encoded by Fisher vector (FV) for staging accuracy enhancement. Differing from the previous studies, a multi-layer FV is investigated to exploit the spatial information rather than the single layer FV. Experimental results show that the proposed method with the dense FV has achieved an area under the receiver of characteristics (AUC) of 96.77%, sensitivity and specificity of 98.04% and 93.75% for the placental maturity staging, respectively. Our experimental results also demonstrate that the dense feature outperforms the traditional sparse feature for placental maturity staging.
Dynamic Multi Layer Signature based Intrusion Detection system Using Mobile Agents
Uddin, Mueen
2010-01-01
Intrusion detection systems have become a key component in ensuring the safety of systems and networks. As networks grow in size and speed continues to increase, it is crucial that efficient scalable techniques should be developed for IDS systems. Signature based detection is the most extensively used threat detection technique for Intrusion Detection Systems (IDS). One of the foremost challenges for signaturebased IDS systems is how to keep up with large volume of incoming traffic when each packet needs to be compared with every signature in the database. When an IDS cannot keep up with the traffic flood, all it can do is to drop packets, therefore, may miss potential attacks. This paper proposes a new model called Dynamic Multi-Layer Signature based IDS using Mobile Agents, which can detect imminent threats with very high success rate by dynamically and automatically creating and using small and efficient multiple databases, and at the same time, provide mechanism to update these small signature databases a...
Collaborative Multi-Layer Network Coding For Hybrid Cellular Cognitive Radio Networks
Moubayed, Abdallah J.
2014-05-01
In this thesis, as an extension to [1], we propose a prioritized multi-layer network coding scheme for collaborative packet recovery in hybrid (interweave and underlay) cellular cognitive radio networks. This scheme allows the uncoordinated collaboration between the collocated primary and cognitive radio base-stations in order to minimize their own as well as each other’s packet recovery overheads, thus by improving their throughput. The proposed scheme ensures that each network’s performance is not degraded by its help to the other network. Moreover, it guarantees that the primary network’s interference threshold is not violated in the same and adjacent cells. Yet, the scheme allows the reduction of the recovery overhead in the collocated primary and cognitive radio networks. The reduction in the cognitive radio network is further amplified due to the perfect detection of spectrum holes which allows the cognitive radio base station to transmit at higher power without fear of violating the interference threshold of the primary network. For the secondary network, simulation results show reductions of 20% and 34% in the packet recovery overhead, compared to the non-collaborative scheme, for low and high probabilities of primary packet arrivals, respectively. For the primary network, this reduction was found to be 12%. Furthermore, with the use of fractional cooperation, the average recovery overhead is further reduced by around 5% for the primary network and around 10% for the secondary network when a high fractional cooperation probability is used.
Fabrication of Multi Layer Insulation DC Break for Microwave Ion Source
International Nuclear Information System (INIS)
To make a compact microwave ion source of 100keV for industrial applications, we are developing the three key components. The first one is a magnetic solenoid with permanent magnets instead of an electromagnet solenoid which requires a high voltage insulation between the ion source and the solenoid or a high voltage floated DC current supply. The second one is a high voltage semiconductor switch that connects or disconnects high voltage power supply for beam extractions to the ion source. With this switch we can control the beam duty to control the average beam current without any tetrode beam extraction geometry or any beam optics component to keep the same beam shape. The last one is DC break in the wave guide between a microwave source such as a magnetron and an ion source. The conventional method for DC break is a choke flange, but that is useful for high voltage less than 50kV. We are developing a multi layer insulation method to obtain the high voltage holding capability higher than 100kV
Multi-Layer Sparse Representation for Weighted LBP-Patches Based Facial Expression Recognition
Directory of Open Access Journals (Sweden)
Qi Jia
2015-03-01
Full Text Available In this paper, a novel facial expression recognition method based on sparse representation is proposed. Most contemporary facial expression recognition systems suffer from limited ability to handle image nuisances such as low resolution and noise. Especially for low intensity expression, most of the existing training methods have quite low recognition rates. Motivated by sparse representation, the problem can be solved by finding sparse coefficients of the test image by the whole training set. Deriving an effective facial representation from original face images is a vital step for successful facial expression recognition. We evaluate facial representation based on weighted local binary patterns, and Fisher separation criterion is used to calculate the weighs of patches. A multi-layer sparse representation framework is proposed for multi-intensity facial expression recognition, especially for low-intensity expressions and noisy expressions in reality, which is a critical problem but seldom addressed in the existing works. To this end, several experiments based on low-resolution and multi-intensity expressions are carried out. Promising results on publicly available databases demonstrate the potential of the proposed approach.
Multi-layer sparse representation for weighted LBP-patches based facial expression recognition.
Jia, Qi; Gao, Xinkai; Guo, He; Luo, Zhongxuan; Wang, Yi
2015-01-01
In this paper, a novel facial expression recognition method based on sparse representation is proposed. Most contemporary facial expression recognition systems suffer from limited ability to handle image nuisances such as low resolution and noise. Especially for low intensity expression, most of the existing training methods have quite low recognition rates. Motivated by sparse representation, the problem can be solved by finding sparse coefficients of the test image by the whole training set. Deriving an effective facial representation from original face images is a vital step for successful facial expression recognition. We evaluate facial representation based on weighted local binary patterns, and Fisher separation criterion is used to calculate the weighs of patches. A multi-layer sparse representation framework is proposed for multi-intensity facial expression recognition, especially for low-intensity expressions and noisy expressions in reality, which is a critical problem but seldom addressed in the existing works. To this end, several experiments based on low-resolution and multi-intensity expressions are carried out. Promising results on publicly available databases demonstrate the potential of the proposed approach. PMID:25808772
Directory of Open Access Journals (Sweden)
Md. Abdullah-al-mamun
2015-08-01
Full Text Available Abstract Humans are capable to identifying diverse shape in the different pattern in the real world as effortless fashion due to their intelligence is grow since born with facing several learning process. Same way we can prepared an machine using human like brain called Artificial Neural Network that can be recognize different pattern from the real world object. Although the various techniques is exists to implementation the pattern recognition but recently the artificial neural network approaches have been giving the significant attention. Because the approached of artificial neural network is like a human brain that is learn from different observation and give a decision the previously learning rule. Over the 50 years research now a days pattern recognition for machine learning using artificial neural network got a significant achievement. For this reason many real world problem can be solve by modeling the pattern recognition process. The objective of this paper is to present the theoretical concept for pattern recognition design using Multi-Layer Perceptorn neural networkin the algorithm of artificial Intelligence as the best possible way of utilizing available resources to make a decision that can be a human like performance.
Xia, Wenjie; Ruiz, Luis; Pugno, Nicola M; Keten, Sinan
2016-03-17
Multi-layer graphene assemblies (MLGs) or fibers with a staggered architecture exhibit high toughness and failure strain that surpass those of the constituent single sheets. However, how the architectural parameters such as the sheet overlap length affect these mechanical properties remains unknown due in part to the limitations of mechanical continuum models. By exploring the mechanics of MLG assemblies under tensile deformation using our established coarse-grained molecular modeling framework, we have identified three different critical interlayer overlap lengths controlling the strength, plastic stress, and toughness of MLGs, respectively. The shortest critical length scale L governs the strength of the assembly as predicted by the shear-lag model. The intermediate critical length L is associated with a dynamic frictional process that governs the strain localization propensity of the assembly, and hence the failure strain. The largest critical length scale L corresponds to the overlap length necessary to achieve 90% of the maximum theoretical toughness of the material. Our analyses provide the general guidelines for tuning the constitutive properties and toughness of multilayer 2D nanomaterials using elasticity, interlayer adhesion energy and geometry as molecular design parameters. PMID:26935048
Noisy contact interactions of multi-layer mechanical structures coupled by boundary conditions
Awrejcewicz, J.; Krysko, V. A., Jr.; Yakovleva, T. V.; Krysko, V. A.
2016-05-01
In this work mathematical models of temporal part of chaos at chosen spatial locations of a plate locally reinforced by ribs taking into account an interplay of their interactions are derived and studied numerically for the most relevant dynamical parameters. In addition, an influence of the additive external noise on chaotic vibrations of multi-layer beam-plate structures coupled only by boundary conditions is investigated. We illustrate and discuss novel nonlinear phenomena of the temporal regular and chaotic contact/no-contact dynamics with the help of Morlet wavelets and Fourier analysis. We show how the additive white noise cancels deterministic chaos close to the boundary of chaotic region in the space of parameters, and we present windows of on/off switching of the frequencies during the contact dynamics between structural members. In order to solve the mentioned design type nonlinear problem we apply methods of qualitative theory of differential equations, the Bubnov-Galerkin method in higher approximations, the Runge-Kutta methods of 4th, 6th and 8th order, as well as the computation and analysis of the largest Lyapunov exponent (Benettin's and Wolf's algorithms are used). The agreement of outcomes of all applied qualitatively different numerical approaches validate our simulation results. In particular, we have illustrated that the Fourier analysis of the studied mechanical structures may yield erroneous results, and hence the wavelet-based analysis is used to investigate chaotic dynamics in the system parameter space.
Cu(III)-independent oxidation and sensing of glucose on multi-layer stacked copper nanoparticles
International Nuclear Information System (INIS)
A highly sensitive electrode for sensing glucose has been fabricated by electropolymerization of 2-amino-5-mercapto-1,3,4-thiadiazole on a solid carbon paste substrate, and subsequent electrodeposition of multi-layer stacked copper particles as an outer surface. The individual copper particles are characterized by a large number of edges and corners of crystallites. Their preferred orientation (111) is parallel to the electrode surface. The conductive polymer interlayer results in an increase of the particle nucleation density and a further decrease of the polarization overpotential for direct (enzyme-free) oxidation of glucose in 0.1 M NaOH solution. A well-shaped voltammetric peak can be observed at around 0.3–0.5 V (vs. SCE, depending on scan rate) that is due to glucose oxidation. This potential is much lower than the one required for Cu(III) formation. A bulk electrolysis experiment using a thin-layer electrochemical cell confirmed the assumption that that glucose undergoes 2-electron oxidation. The mechanism of glucose oxidation in the absence of Cu(III) is discussed. The electrode exhibits a very high sensitivity (slope) of 3.31 mA cm−2 mM−1, and the detection limit is 2 μM (at an SNR of 3). Features of the new sensor include the ease of fabrication, its high stability and good selectivity. (author)
Multi-layered multi-pattern CPG for adaptive locomotion of humanoid robots.
Nassour, John; Hénaff, Patrick; Benouezdou, Fethi; Cheng, Gordon
2014-06-01
In this paper, we present an extended mathematical model of the central pattern generator (CPG) in the spinal cord. The proposed CPG model is used as the underlying low-level controller of a humanoid robot to generate various walking patterns. Such biological mechanisms have been demonstrated to be robust in locomotion of animal. Our model is supported by two neurophysiological studies. The first study identified a neural circuitry consisting of a two-layered CPG, in which pattern formation and rhythm generation are produced at different levels. The second study focused on a specific neural model that can generate different patterns, including oscillation. This neural model was employed in the pattern generation layer of our CPG, which enables it to produce different motion patterns-rhythmic as well as non-rhythmic motions. Due to the pattern-formation layer, the CPG is able to produce behaviors related to the dominating rhythm (extension/flexion) and rhythm deletion without rhythm resetting. The proposed multi-layered multi-pattern CPG model (MLMP-CPG) has been deployed in a 3D humanoid robot (NAO) while it performs locomotion tasks. The effectiveness of our model is demonstrated in simulations and through experimental results. PMID:24570353
iBole：A Hybrid Multi-Layer Architecture for Doctor Recommendation in Medical Social Networks
Institute of Scientific and Technical Information of China (English)
宫继兵; 王立; 孙胜涛; 彭思维
2015-01-01
In this paper, we try to systematically study how to perform doctor recommendation in medical social net-works (MSNs). Specifically, employing a real-world medical dataset as the source in our work, we propose iBole, a novel hybrid multi-layer architecture, to solve this problem. First, we mine doctor-patient relationships/ties via a time-constraint probability factor graph model (TPFG). Second, we extract network features for ranking nodes. Finally, we propose RWR-Model, a doctor recommendation model via the random walk with restart method. Our real-world experiments validate the effectiveness of the proposed methods. Experimental results show that we obtain good accuracy in mining doctor-patient relationships from the network, and the doctor recommendation performance is better than that of the baseline algorithms:traditional Ranking SVM (RSVM) and the individual doctor recommendation model (IDR-Model). The results of our RWR-Model are more reasonable and satisfactory than those of the baseline approaches.
Multi-layer film flow down an inclined plane: experimental investigation
Henry, Daniel
2014-11-19
We report the results from an experimental study of the flow of a film down an inclined plane where the film itself is comprised of up to three layers of different liquids. By measuring the total film thickness for a broad range of parameters including flow rates and liquid physical properties, we provide a thorough and systematic test of the single-layer approximation for multi-layer films for Reynolds numbers Re = ρQ/μ≈0.03-60. In addition, we also measure the change in film thickness of individual layers as a function of flow rates for a variety of experimental configurations. With the aid of high-speed particle tracking, we derive the velocity fields and free-surface velocities to compare to the single-layer approximation. Furthermore, we provide experimental evidence of small capillary ridge formations close to the point where two layers merge and compare our experimental parameter range for the occurrence of this phenomenon to those previously reported.
A simple method for fabricating multi-layer PDMS structures for 3D microfluidic chips
Zhang, Mengying
2010-01-01
We report a simple methodology to fabricate PDMS multi-layer microfluidic chips. A PDMS slab was surface-treated by trichloro (1H,1H,2H,2H-perfluorooctyl) silane, and acts as a reusable transferring layer. Uniformity of the thickness of the patterned PDMS layer and the well-alignment could be achieved due to the transparency and proper flexibility of this transferring layer. Surface treatment results are confirmed by XPS and contact angle testing, while bonding forces between different layers were measured for better understanding of the transferring process. We have also designed and fabricated a few simple types of 3D PDMS chip, especially one consisting of 6 thin layers (each with thickness of 50 μm), to demonstrate the potential utilization of this technique. 3D fluorescence images were taken by a confocal microscope to illustrate the spatial characters of essential parts. This fabrication method is confirmed to be fast, simple, repeatable, low cost and possible to be mechanized for mass production. © The Royal Society of Chemistry 2010.
Examining the impact of multi-layer graphene using cellular and amphibian models
Muzi, Laura; Mouchet, Florence; Cadarsi, Stéphanie; Janowska, Izabela; Russier, Julie; Ménard-Moyon, Cécilia; Risuleo, Gianfranco; Soula, Brigitte; Galibert, Anne-Marie; Flahaut, Emmanuel; Pinelli, Eric; Gauthier, Laury; Bianco, Alberto
2016-06-01
In the last few years, graphene has been defined as the revolutionary material showing an incredible expansion in industrial applications. Different graphene forms have been applied in several contexts, spreading from energy technologies and electronics to food and agriculture technologies. Graphene showed promises also in the biomedical field. Hopeful results have been already obtained in diagnostic, drug delivery, tissue regeneration and photothermal cancer ablation. In view of the enormous development of graphene-based technologies, a careful assessment of its impact on health and environment is demanded. It is evident how investigating the graphene toxicity is of fundamental importance in the context of medical purposes. On the other hand, the nanomaterial present in the environment, likely to be generated all along the industrial life-cycle, may have harmful effects on living organisms. In the present work, an important contribution on the impact of multi-layer graphene (MLG) on health and environment is given by using a multifaceted approach. For the first purpose, the effect of the material on two mammalian cell models was assessed. Key cytotoxicity parameters were considered such as cell viability and inflammatory response induction. This was combined with an evaluation of MLG toxicity towards Xenopus laevis, used as both in vivo and environmental model organism.
Experimental Study of Weepage in Multi-layer Glass Reinforced Piping
Al Sinan, Hussain
2014-05-01
Glass Reinforced Polymer pipes, commonly used in water transport applications, are prone to long term weepage. Weepage is defined as the transfer of fluid through the pipe and is considered a functional failure. An experimental investigation of weepage in multi-layered GRP pipes was carried out in two parts aiming to understand the phenomenon to help enhance the weepage resistance of manufactured pipes. First, liner surface profilometry investigation was carried out to identify microscopic features that might serve in initiating weepage. Second, MRI and x-ray tomography and SEM imaging of pipe samples aged with water and dye penetrant was carried out to capture weepage development through the pipe thickness. Diffusion through liner fiber/resin interface, propagation in the direction of poorly wetted hoop fibers and transverse cracks were found to be the likely causes of accelerating weepage in the samples. Fiber rich zones in the liner were considered weak spots that water can use for fast penetration of the liner. Finally, polyester netting used to hold core layer was found to help in water accumulation and transport through the pipe increasing the chances of failure.
Multi-Layer 5G Mobile Phone Antenna for Multi-User MIMO Communications
DEFF Research Database (Denmark)
Ojaroudiparchin, Naser; Shen, Ming; Pedersen, Gert F.
2015-01-01
In this study, a new design of multi-layer phased array antenna for millimeter-wave (mm-Wave) fifth generation (5G) mobile terminals is proposed. The proposed linear phased array antenna is designed on four layers of the Rogers RT5880 substrates to operate at 28 GHz which is under consideration for...... 5G wireless communications. Two identical linear sub arrays can be simultaneously used at different sides of the mobile-phone printed circuit board (PCB) for operation in diversity or multiple-input multiple-output (MIMO) modes. Each sub array contains eight elements of very compact off......-center dipole antennas with dimensions of 5.4×0.67 mm2. The feature of compact design with good beam-steering function makes them well-suited to integrate into the mobile-phone mock-up. The fundamental properties of the proposed antenna have been investigated. Simulations show that the proposed 5G antenna is...
Preparation and Evaluation of Multi-Layer Anodes of Solid Oxide Fuel Cell
Santiago, Diana; Farmer, Serene C.; Setlock, John A.
2012-01-01
The development of an energy device with abundant energy generation, ultra-high specific power density, high stability and long life is critical for enabling longer missions and for reducing mission costs. Of all different types of fuel cells, the solid oxide fuel cells (SOFC) is a promising high temperature device that can generate electricity as a byproduct of a chemical reaction in a clean way and produce high quality heat that can be used for other purposes. For aerospace applications, a power-to-weight of (is) greater than 1.0 kW/kg is required. NASA has a patented fuel cell technology under development, capable of achieving the 1.0 kW/kg figure of merit. The first step toward achieving these goals is increasing anode durability. The catalyst plays an important role in the fuel cells for power generation, stability, efficiency and long life. Not only the anode composition, but its preparation and reduction are key to achieving better cell performance. In this research, multi-layer anodes were prepared varying the chemistry of each layer to optimize the performance of the cells. Microstructure analyses were done to the new anodes before and after fuel cell operation. The cells' durability and performance were evaluated in 200 hrs life tests in hydrogen at 850 C. The chemistry of the standard nickel anode was modified successfully reducing the anode degradation from 40% to 8.4% in 1000 hrs and retaining its microstructure.
Unified Multi-Layer among Software Defined Multi-Domain Optical Networks (Invited
Directory of Open Access Journals (Sweden)
Hui Yang
2015-06-01
Full Text Available The software defined networking (SDN enabled by OpenFlow protocol has gained popularity which can enable the network to be programmable and accommodate both fixed and flexible bandwidth services. In this paper, we present a unified multi-layer (UML architecture with multiple controllers and a dynamic orchestra plane (DOP for software defined multi-domain optical networks. The proposed architecture can shield the differences among various optical devices from multi-vendors and the details of connecting heterogeneous networks. The cross-domain services with on-demand bandwidth can be deployed via unified interfaces provided by the dynamic orchestra plane. Additionally, the globalization strategy and practical capture of signal processing are presented based on the architecture. The overall feasibility and efficiency of the proposed architecture is experimentally verified on the control plane of our OpenFlow-based testbed. The performance of globalization strategy under heavy traffic load scenario is also quantitatively evaluated based on UML architecture compared with other strategies in terms of blocking probability, average hops, and average resource consumption.
Multi-layer onion drying: Study of mass and heat transfer mechanism and quality evaluation
Asiah, N.; Djaeni, M.
2015-12-01
Drying is one of methods to prolong storage life of onion. The outer layer of onion has kept dry around 12% of moisture content or below to retain the freshness of its inside part. The model of multi layers onion drying is very important to predict the water and temperature transport during dying process. In this case, one dimensional partial equation was used for predicting moisture distribution in the onion layer. To support the study, the onion drying was performed at various temperatures ranging of 40-50 °C. Then the attribute quality (quercetin content) of dried onion was analysed. The experimental data was to validate the value of water diffusivity and mass transfer coefficient used in the model. Results showed that the model can predict moisture distribution in each layer of onion. Moreover, based on the average moisture content during the drying, the model result closed to experiment data with accuracy of R2 0.970-0.999. The model was useful to estimate the drying time of outer layer to the desired level. Besides that, the quality evaluation showed that after 2 hours drying process, quercetin content can be retained.
Achievable Rates of Cognitive Radio Networks Using Multi-Layer Coding with Limited CSI
Sboui, Lokman
2016-03-01
In a Cognitive Radio (CR) framework, the channel state information (CSI) feedback to the secondary transmitter (SU Tx) can be limited or unavailable. Thus, the statistical model is adopted in order to determine the system performance using the outage concept. In this paper, we adopt a new approach using multi-layer-coding (MLC) strategy, i.e., broadcast approach, to enhance spectrum sharing over fading channels. First, we consider a scenario where the secondary transmitter has no CSI of both the link between SU Tx and the primary receiver (cross-link) and its own link. We show that using MLC improves the cognitive rate compared to the rate provided by a singlelayer- coding (SLC). In addition, we observe numerically that 2-Layer coding achieves most of the gain for Rayleigh fading. Second, we analyze a scenario where SU Tx is provided by partial CSI about its link through quantized CSI. We compute its achievable rate adopting the MLC and highlight the improvement over SLC. Finally, we study the case in which the cross-link is perfect, i.e., a cooperative primary user setting, and compare the performance with the previous cases. We present asymptotic analysis at high power regime and show that the cooperation enhances considerably the cognitive rate at high values of the secondary power budget.
Collaborative Multi-Layer Network Coding in Hybrid Cellular Cognitive Radio Networks
Moubayed, Abdallah
2015-05-01
In this paper, as an extension to [1], we propose a prioritized multi-layer network coding scheme for collaborative packet recovery in hybrid (interweave and underlay) cellular cognitive radio networks. This scheme allows the uncoordinated collaboration between the collocated primary and cognitive radio base-stations in order to minimize their own as well as each other\\'s packet recovery overheads, thus by improving their throughput. The proposed scheme ensures that each network\\'s performance is not degraded by its help to the other network. Moreover, it guarantees that the primary network\\'s interference threshold is not violated in the same and adjacent cells. Yet, the scheme allows the reduction of the recovery overhead in the collocated primary and cognitive radio networks. The reduction in the cognitive radio network is further amplified due to the perfect detection of spectrum holes which allows the cognitive radio base station to transmit at higher power without fear of violating the interference threshold of the primary network. For the secondary network, simulation results show reductions of 20% and 34% in the packet recovery overhead, compared to the non-collaborative scheme, for low and high probabilities of primary packet arrivals, respectively. For the primary network, this reduction was found to be 12%. © 2015 IEEE.
Wafer-scale synthesis of multi-layer graphene by high-temperature carbon ion implantation
International Nuclear Information System (INIS)
We report on the synthesis of wafer-scale (4 in. in diameter) high-quality multi-layer graphene using high-temperature carbon ion implantation on thin Ni films on a substrate of SiO2/Si. Carbon ions were bombarded at 20 keV and a dose of 1 × 1015 cm−2 onto the surface of the Ni/SiO2/Si substrate at a temperature of 500 °C. This was followed by high-temperature activation annealing (600–900 °C) to form a sp2-bonded honeycomb structure. The effects of post-implantation activation annealing conditions were systematically investigated by micro-Raman spectroscopy and transmission electron microscopy. Carbon ion implantation at elevated temperatures allowed a lower activation annealing temperature for fabricating large-area graphene. Our results indicate that carbon-ion implantation provides a facile and direct route for integrating graphene with Si microelectronics
Chiral braided and woven composites: design, fabrication, and electromagnetic characterization
Wheeland, Sara; Bayatpur, Farhad; Amirkhizi, Alireza V.; Nemat-Nasser, Sia
2011-04-01
This work presents a new chiral composite composed of copper wires braided with Kevlar and nylon to form conductive coils integrated among structural fiber. To create a fabric, these braids were woven with plain Kevlar fiber. This yielded a composite with all coils possessing the same handedness, producing a chiral material. The electromagnetic response of this fabric was first simulated using a finite element full-wave simulation. For the electromagnetic measurement, the sample was placed between two lens-horn antennas connected to a Vector Network Analyzer. The frequency response of the sample was scanned between 5.5 and 8GHz. The measured scattering parameters were then compared to those of the simulated model. The measured parameters agreed well with the simulation results, showing a considerable chirality within the measured frequency band. The new composite combines the strength and durability of traditional composites with an electromagnetic design to create a multifunctional material.
Changes of the hydrodynamic conditions in the braided river
Directory of Open Access Journals (Sweden)
Karol PLESIŃSKI
2014-11-01
Full Text Available The paper focuses on the understanding of the basic hydrodynamic conditions along the braided gravel-bed river. The measuring cross-section was located in the Ochotnica River, where its braided channel development was observed. Investigations take place from 2003 up to 2014. Measurements were performed for selected characteristic points. The study focused mostly on the measurements of water velocities under different flow conditions, and next on finding basic hydraulic parameters of flow: shear velocity, shear stresses, Reynolds number, Froude number. In addition, the gravel material from the river bed was examined, in order to find sedimentological characteristics of it.
Introduction to complex reflection groups and their braid groups
Broué, Michel
2010-01-01
Weyl groups are particular cases of complex reflection groups, i.e. finite subgroups of GLr(C) generated by (pseudo)reflections. These are groups whose polynomial ring of invariants is a polynomial algebra. It has recently been discovered that complex reflection groups play a key role in the theory of finite reductive groups, giving rise as they do to braid groups and generalized Hecke algebras which govern the representation theory of finite reductive groups. It is now also broadly agreed upon that many of the known properties of Weyl groups can be generalized to complex reflection groups. The purpose of this work is to present a fairly extensive treatment of many basic properties of complex reflection groups (characterization, Steinberg theorem, Gutkin-Opdam matrices, Solomon theorem and applications, etc.) including the basic findings of Springer theory on eigenspaces. In doing so, we also introduce basic definitions and properties of the associated braid groups, as well as a quick introduction to Bessis' ...
Electron beam processing of carbon fibre reinforced braided composites
International Nuclear Information System (INIS)
The possibility of producing a new type carbon fibre reinforced composite profile has been examined by applying braiding, a well-known process of textile technology. Pipe and hollow profile composite products can be manufactured this way by applying Electron Beam curing. The fabric-like braided reinforcing structure was manufactured out of Hungarian-made carbon fibre roving of 48,000 elementary fibres. The mutual irradiation of the system impregnated with epoxy-acrylate oligomer by 8 MeV EB resulted in better mechanical properties then conventional chemical curing. Owing to its low density and high specific strength this new composite product can possibly be applied in dynamically loaded structures e.g. in the automotive industry
Braids as a representation space of SU(5)
Cartin, Daniel
2015-01-01
The Standard Model of particle physics provides very accurate predictions of phenomena occurring at the sub-atomic level, but the reason for the choice of symmetry group and the large number of particles considered elementary, is still unknown. Along the lines of previous preon models positing a substructure to explain these aspects, Bilson-Thompson showed how the first family of elementary particles is realized as the crossings of braids made of three strands, with charges resulting from twi...
Electron beam processing of carbon fibre reinforced braided composites beams
International Nuclear Information System (INIS)
Complete text of publication follows. In this paper the possibility of producing a new type carbon fiber reinforced composite is examined by applying braiding, a well-known process of textile technology. The appearance of the new Hungarian carbon fiber with excellent mechanical properties in the market enables the development of newer type carbon fiber reinforced composites in the continuously widening range of engineering applications. Advanced hollow profiles, pipes and other composite products can be manufactured in continuous operation. A new way of composite production of this kind is the manufacturing of reinforcing structure by braiding technology producing a composite with sufficient mechanical properties from this cross directional fabric-like textile structure by impregnation. This manufacturing process can complete the variety of hollow products serving the same purpose as pultrusion or filament winding. This way a profile type framework element with a hollow cross section is manufactured having favorable mechanical properties. Owing to its small mass and high specific strength this product can be applied in dynamically loaded structures e.g. in the automotive industry. For crosslinking of the matrix the method of high-speed electron beam curing has been examined in order to reach continuous operation. The field of use and application of carbon fiber braided structures has a great chance especially in machine engineering and in the automotive industry. The main reason for this is that braiding processes are capable of producing structures having good mechanical properties at a low processing price. The mass of the composite load-bearing structure produced this way is one fifth of the steel product having similar geometry, and its specific mechanical properties are nearly as good as that of the most commonly applied semiproduct and structural component, the welded steel profile
Knots, Braids and Hedgehogs from the Eikonal Equation
Wereszczynski, A.
2005-01-01
The complex eikonal equation in the three space dimensions is considered. We show that apart from the recently found torus knots this equation can also generate other topological configurations with a non-trivial value of the $\\pi_2(S^2)$ index: braided open strings as well as hedgehogs. In particular, cylindric strings i.e. string solutions located on a cylinder with a constant radius are found. Moreover, solutions describing strings lying on an arbitrary surface topologically equivalent to ...
Duality Theorem and Drinfeld Double in Braided Tensor Categories
Institute of Scientific and Technical Information of China (English)
Shouchuan Zhang
2003-01-01
Let (C, ( ), I, C) be a braided tensor category. For a finite Hopf algebra H in c with CH, H = C-1 H,H, the duality theorem is shown, i.e.,(R#H)#H^* ≌ R( ) (H-( )H^*)as algebras in C. Also, it is proved that the Drinfeld double (D(H), [b]) is a quasi-triangular Hopf algebra in c.
Hurwitz equivalence of braid monodromies and extremal elliptic surfaces
Degtyarev, Alex
2009-01-01
We discuss the equivalence between the categories of certain ribbon graphs and subgroups of the modular group $\\Gamma$ and use it to construct exponentially large families of not Hurwitz equivalent simple braid monodromy factorizations of the same element. As an application, we also obtain exponentially large families of {\\it topologically} distinct algebraic objects such as extremal elliptic surfaces, real trigonal curves, and real elliptic surfaces.
Development of braided drug-loaded nanofiber sutures
International Nuclear Information System (INIS)
The objectives of this work are twofold. Firstly, while most work on electrospinning is limited to the development of only functional materials, a structural application of electrospun nanofibers is explored. Secondly, a drug-loaded tissue suture is fabricated and its various properties are characterized. Braided drug-loaded nanofiber sutures are obtained by combining an electrospinning process with a braiding technique followed by a coating procedure. Two different electrospinning techniques, i.e. blend and coaxial electrospinning, to incorporate a model drug cefotaxime sodium (CFX-Na) into poly(L-lactic acid) (PLLA) nanofibers have been applied and compared with each other. Properties of the braided drug-loaded sutures are characterized through a variety of methods including SEM, TEM and tensile testing. The results show that the nanofibers had a preferable micromorphology. The drug was incorporated into the polymer nanofibers homogeneously, with no cross-linking. The nanofibers maintained their fibrous structures. An in vitro release study indicates that the drug-loaded nanofibers fabricated by blend electrospinning and coaxial electrospinning had a different drug release behavior. An inhibition zone experiment shows that both sutures obtained from the nanofibers of the different electrospinning techniques had favorable antibacterial properties. The drug-loaded sutures had preferable histological compatibility performance compared with commercial silk sutures in an in vivo comparative study.
Characterization of Triaxial Braided Composite Material Properties for Impact Simulation
Roberts, Gary D.; Goldberg, Robert K.; Biniendak, Wieslaw K.; Arnold, William A.; Littell, Justin D.; Kohlman, Lee W.
2009-01-01
The reliability of impact simulations for aircraft components made with triaxial braided carbon fiber composites is currently limited by inadequate material property data and lack of validated material models for analysis. Improvements to standard quasi-static test methods are needed to account for the large unit cell size and localized damage within the unit cell. The deformation and damage of a triaxial braided composite material was examined using standard quasi-static in-plane tension, compression, and shear tests. Some modifications to standard test specimen geometries are suggested, and methods for measuring the local strain at the onset of failure within the braid unit cell are presented. Deformation and damage at higher strain rates is examined using ballistic impact tests on 61- by 61- by 3.2-mm (24- by 24- by 0.125-in.) composite panels. Digital image correlation techniques were used to examine full-field deformation and damage during both quasi-static and impact tests. An impact analysis method is presented that utilizes both local and global deformation and failure information from the quasi-static tests as input for impact simulations. Improvements that are needed in test and analysis methods for better predictive capability are examined.
Simulation of braiding anyons using matrix product states
Ayeni, Babatunde M.; Singh, Sukhwinder; Pfeifer, Robert N. C.; Brennen, Gavin K.
2016-04-01
Anyons exist as pointlike particles in two dimensions and carry braid statistics, which enable interactions that are independent of the distance between the particles. Except for a relatively few number of models, which are analytically tractable, much of the physics of anyons remains still unexplored. In this paper, we show how U(1) symmetry can be combined with the previously proposed anyonic matrix product states to simulate ground states and dynamics of anyonic systems on a lattice at any rational particle number density. We provide proof of principle by studying itinerant anyons on a one-dimensional chain where no natural notion of braiding arises and also on a two-leg ladder where the anyons hop between sites and possibly braid. We compare the result of the ground-state energies of Fibonacci anyons against hardcore bosons and spinless fermions. In addition, we report the entanglement entropies of the ground states of interacting Fibonacci anyons on a fully filled two-leg ladder at different interaction strength, identifying gapped or gapless points in the parameter space. As an outlook, our approach can also prove useful in studying the time dynamics of a finite number of non-Abelian anyons on a finite two-dimensional lattice.
Development of braided drug-loaded nanofiber sutures
Energy Technology Data Exchange (ETDEWEB)
Hu Wen [School of Materials Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Huang Zhengming [School of Aerospace Engineering and Applied Mechanics, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Liu Xiangyang, E-mail: huangzm@tongji.edu.cn [Department of Physics, National University of Singapore, 2 Science Drive 3, 117542 (Singapore)
2010-08-06
The objectives of this work are twofold. Firstly, while most work on electrospinning is limited to the development of only functional materials, a structural application of electrospun nanofibers is explored. Secondly, a drug-loaded tissue suture is fabricated and its various properties are characterized. Braided drug-loaded nanofiber sutures are obtained by combining an electrospinning process with a braiding technique followed by a coating procedure. Two different electrospinning techniques, i.e. blend and coaxial electrospinning, to incorporate a model drug cefotaxime sodium (CFX-Na) into poly(L-lactic acid) (PLLA) nanofibers have been applied and compared with each other. Properties of the braided drug-loaded sutures are characterized through a variety of methods including SEM, TEM and tensile testing. The results show that the nanofibers had a preferable micromorphology. The drug was incorporated into the polymer nanofibers homogeneously, with no cross-linking. The nanofibers maintained their fibrous structures. An in vitro release study indicates that the drug-loaded nanofibers fabricated by blend electrospinning and coaxial electrospinning had a different drug release behavior. An inhibition zone experiment shows that both sutures obtained from the nanofibers of the different electrospinning techniques had favorable antibacterial properties. The drug-loaded sutures had preferable histological compatibility performance compared with commercial silk sutures in an in vivo comparative study.
Structural and optical studies of nanostructured TiO2–Ge multi-layer thin films
International Nuclear Information System (INIS)
This paper reports the effects of annealing on structural and optical properties of nanostructured multi-layer TiO2–Ge thin films. These films were characterized using different techniques such as X-ray diffraction, X-ray reflectivity, Rutherford backscattering (RBS), and Fourier Transform Infrared spectroscopy. Annealing was responsible for pronounced changes in structural and optical properties of these films, as associated with changes in their structures, stoichiometry and stress-state. Three sets of TiO2–Ge multi-layer films were deposited by electron beam evaporation and resistive heating with different Ge layer thickness (5, 10 and 15 nm), and TiO2 layer thickness was fixed to 20 nm. The films were annealed in air up to 500 °C for 2 h. RBS studies showed that the layer structure of TiO2–Ge multi-layer films had been formed. The absorption spectra and band gap energy showed a blue shift with decrease in Ge layer thickness. The absorption spectra of these films suggest quantum confinement that increases with annealing temperature before the complete oxidation of Ge. Apparently complete oxidation results in sudden or sharp rise in band gap energy that matches with that of TiO2. RBS study reveals that layered structure of TiO2–Ge multi-layer films is not destroyed by annealing, which may be due to non-wetting behavior of Ge and its oxide with TiO2. These results imply that nanostructured TiO2–Ge multi-layer thin films may be employed as heterojunctions (with tunable band gap energy) based on quantum confinement effects for use in photovoltaics. - Highlights: • Nanostructured multi-layer TiO2–Ge films were deposited by electron beam evaporation. • The layered structure of the films was not destroyed by annealing. • The band gap energy showed a blue shift with Germanium (Ge) layer thickness. • The absorption spectra of these films suggest quantum confinement. • The films with lower Ge thickness oxidize at lower annealing temperatures
Symmetry-protected non-Abelian braiding of Majorana Kramers' pairs
Gao, Pin; Liu, Xiong-Jun
2016-01-01
We show the complete symmetry conditions for non-Abelian braiding of Majorana Kramers' pairs (MKPs) in a time-reversal (TR) invariant topological superconductor. By introducing an effective Hamiltonian approach to describe the braiding of MKPs, we show that the non-Abelian braiding is protected when the effective Hamiltonian exhibits a new TR like anti-unitary symmetry, which is satisfied if the system is free of dynamical noise. Further, even the dynamical noise may not cause error in braidi...
DETERMINATION OF INTERNAL STRAIN IN 3-D BRAIDED COMPOSITES USING OPTIC FIBER STRAIN SENSORS
Institute of Scientific and Technical Information of China (English)
YuanShenfang; HuangRui; LiXianghua; LiuXiaohui
2004-01-01
A reliable understanding of the properties of 3-D braided composites is of primary importance for proper utilization of these materials. A new method is introduced to study the mechanical performance of braided composite materials using embedded optic fiber sensors. Experimental research is performed to devise a method of incorporating optic fibers into a 3-D braided composite structure. The efficacy of this new testing method is evaluated on two counts. First,the optical performance of optic fibers is studied before and after incorporated into 3-D braided composites, as well as after completion of the manufacturing process for 3-D braided composites,to validate the ability of the optic fiber to survive the manufacturing process. On the other hand,the influence of incorporated optic fiber on the original braided composite is also researched by tension and compression experiments. Second, two kinds of optic fiber sensors are co-embedded into 3-D braided composites to evaluate their respective ability to measure the internal strain.Experimental results show that multiple optic fiber sensors can be co-braided into 3-D braided composites to determine their internal strain which is difficult to be fulfilled by other current existing methods.
Electrochemical behavior of hydroxyapatite/TiN multi-layer coatings on Ti alloys
International Nuclear Information System (INIS)
The electrochemical behavior of hydroxyapatite (HA) and titanium nitride (TiN) multi-layer coatings on Ti–Nb–Zr alloys was investigated by a variety of surface analytical methods. The HA/TiN layers were deposited using a magnetron sputtering system. The HA target was made of human tooth-ash sintered at 1300 °C for 1 h and had an average Ca/P ratio of 1.9. From X-ray diffraction patterns, the Ti–29Nb–5Zr alloy was composed entirely of equiaxed β-phase exhibiting the principal (110) reflection, and the coating exhibited the (111) and (200) reflections for TiN and the (112) and (202) reflections for HA. At the coating surface the HA films consisted of granular particles, and the surface roughness was 4.22 nm. The thickness of the coating layers increased in the order of HA/TiN (lowest), TiN, and HA (highest). Potentiodynamic polarization measurements revealed that the corrosion current density was the lowest, and the corrosion potential and polarization resistance the highest, when the Ti–29Nb–5Zr surface was covered by the HA/TiN film, compared to solely HA or TiN films. - Highlights: • HA/TiN films were deposited by magnetron sputtering on a Ti–29Nb–5Zr biomedical alloy. • The corrosion current density for the HA/TiN films was lower than that of the non-coated alloy. • The polarization resistance of the HA/TiN films was higher than that of the non-coated alloy
Electrochemical behavior of hydroxyapatite/TiN multi-layer coatings on Ti alloys
Energy Technology Data Exchange (ETDEWEB)
Kim, Eun-Ju [Department of Dental Materials, Research Center of Nano-Interface Activation for Biomaterials, School of Dentistry, Chosun University (Korea, Republic of); Jeong, Yong-Hoon [Biomechanics and Tissue Engineering Laboratory, Division of Orthodontics, College of Dentistry, The Ohio State University, Columbus, OH (United States); Choe, Han-Cheol, E-mail: hcchoe@chosun.ac.kr [Department of Dental Materials, Research Center of Nano-Interface Activation for Biomaterials, School of Dentistry, Chosun University (Korea, Republic of); Brantley, William A. [Division of Restorative Science and Prosthodontics, College of Dentistry, The Ohio State University, Columbus, OH (United States)
2014-12-01
The electrochemical behavior of hydroxyapatite (HA) and titanium nitride (TiN) multi-layer coatings on Ti–Nb–Zr alloys was investigated by a variety of surface analytical methods. The HA/TiN layers were deposited using a magnetron sputtering system. The HA target was made of human tooth-ash sintered at 1300 °C for 1 h and had an average Ca/P ratio of 1.9. From X-ray diffraction patterns, the Ti–29Nb–5Zr alloy was composed entirely of equiaxed β-phase exhibiting the principal (110) reflection, and the coating exhibited the (111) and (200) reflections for TiN and the (112) and (202) reflections for HA. At the coating surface the HA films consisted of granular particles, and the surface roughness was 4.22 nm. The thickness of the coating layers increased in the order of HA/TiN (lowest), TiN, and HA (highest). Potentiodynamic polarization measurements revealed that the corrosion current density was the lowest, and the corrosion potential and polarization resistance the highest, when the Ti–29Nb–5Zr surface was covered by the HA/TiN film, compared to solely HA or TiN films. - Highlights: • HA/TiN films were deposited by magnetron sputtering on a Ti–29Nb–5Zr biomedical alloy. • The corrosion current density for the HA/TiN films was lower than that of the non-coated alloy. • The polarization resistance of the HA/TiN films was higher than that of the non-coated alloy.
Vortex stability in a multi-layer quasi-geostrophic model: application to Mediterranean Water eddies
Energy Technology Data Exchange (ETDEWEB)
Carton, Xavier; Ménesguen, Claire; Meunier, Thomas [Laboratoire de Physique des Oceans, UBO/IFREMER/CNRS/IRD, Brest (France); Sokolovskiy, Mikhail [Institute of Water Problems of the RAS, Moscow (Russian Federation); Aguiar, Ana, E-mail: xcarton@univ-brest.fr [Instituto Dom Luiz, Universidade de Lisboa, Lisbon (Portugal)
2014-12-01
The stability of circular vortices to normal mode perturbations is studied in a multi-layer quasi-geostrophic model. The stratification is fitted on the Gulf of Cadiz where many Mediterranean Water (MW) eddies are generated. Observations of MW eddies are used to determine the parameters of the reference experiment; sensitivity tests are conducted around this basic case. The objective of the study is two-fold: (a) determine the growth rates and nonlinear evolutions of unstable perturbations for different three-dimensional (3D) velocity structures of the vortices, (b) check if the different structure of our idealized vortices, mimicking MW cyclones and anticyclones, can induce different stability properties in a model that conserves parity symmetry, and apply these results to observed MW eddies. The linear stability analysis reveals that, among many 3D distributions of velocity, the observed eddies are close to maximal stability, with instability time scales longer than 100 days (these time scales would be less than 10 days for vertically more sheared eddies). The elliptical deformation is most unstable for realistic eddies (the antisymmetric one dominates for small eddies and the triangular one for large eddies); the antisymmetric mode is stronger for cyclones than for anticyclones. Nonlinear evolutions of eddies with radii of about 30 km, and elliptically perturbed, lead to their re-organization into 3D tripoles; smaller eddies are stable and larger eddies break into 3D dipoles. Horizontally more sheared eddies are more unstable and sustain more asymmetric instabilities. In summary, few differences were found between cyclone and anticyclone stability, except for strong horizontal velocity shears. (paper)
A design philosophy for multi-layer neural networks with applications to robot control
Vadiee, Nader; Jamshidi, MO
1989-01-01
A system is proposed which receives input information from many sensors that may have diverse scaling, dimension, and data representations. The proposed system tolerates sensory information with faults. The proposed self-adaptive processing technique has great promise in integrating the techniques of artificial intelligence and neural networks in an attempt to build a more intelligent computing environment. The proposed architecture can provide a detailed decision tree based on the input information, information stored in a long-term memory, and the adapted rule-based knowledge. A mathematical model for analysis will be obtained to validate the cited hypotheses. An extensive software program will be developed to simulate a typical example of pattern recognition problem. It is shown that the proposed model displays attention, expectation, spatio-temporal, and predictory behavior which are specific to the human brain. The anticipated results of this research project are: (1) creation of a new dynamic neural network structure, and (2) applications to and comparison with conventional multi-layer neural network structures. The anticipated benefits from this research are vast. The model can be used in a neuro-computer architecture as a building block which can perform complicated, nonlinear, time-varying mapping from a multitude of input excitory classes to an output or decision environment. It can be used for coordinating different sensory inputs and past experience of a dynamic system and actuating signals. The commercial applications of this project can be the creation of a special-purpose neuro-computer hardware which can be used in spatio-temporal pattern recognitions in such areas as air defense systems, e.g., target tracking, and recognition. Potential robotics-related applications are trajectory planning, inverse dynamics computations, hierarchical control, task-oriented control, and collision avoidance.
Substrate- and interface-mediated photocrystallization in a-Se films and multi-layers
Lindberg, G. P.; Tallman, R. E.; Weinstein, B. A.; Abbaszadeh, S.; Karim, K. S.; Reznik, A.
2012-02-01
Photocrystallization in a-Se films and layered a-Se structures is studied by Raman scattering as a function of temperature for photon energies near or slightly below the band gap. The samples are ˜16.5 μm thick films of a-Se grown i) directly on glass, ii) on indium tin oxide (ITO) coated glass, iii) on glass that is spin coated with 800nm polymide, and iv) on a Capton sheet. A low As-concentration (< 0.2 %) is present in several of the a-Se films. We compare the results on these samples to prior findings on a-Se HARP targets, and on a polymer-encapsulated a-Se film [1]. We observe strong evidence that the interface between the a-Se film and the underlying substrate and/or multi-layers plays an important role in the onset time and growth rate of photocrystallized Se domains. In some samples a discontinuous increase in the onset time with increasing temperature occurs near the glass transition (˜310K), and there is a surprising ``dead zone'' of no crystallization in this region. Other samples merely show a minimum in the onset time at similar temperatures, but no discontinuity and no region where crystallization is absent. Soft intermediate layers appear to increase stability against crystallization in an overlying a-Se film. The competing effects of substrate shear strain and thermal driving forces on the photocrystallization process are considered to account for these findings. [4pt] [1] R.E. Tallman et. al. J. Non-crystalline Sols. 354, 4577-81 (2008)
Dose-Depth Distributions Produced by Electrons in Multi-Layer Targets
International Nuclear Information System (INIS)
The purpose of this study is to solve a series of practical problems involving the use of electron beam and beta sources for radiation processing applications. Monte Carlo computations were performed to determine the energy absorption, reflection and transmission for the following configurations: plane parallel source of mono-energetic electrons incident on one face of a slab of a multi-layered target; planar and line sources with electrons incident on cylindrical targets. The slab calculations were performed as a function of target composition (water, iron and polyethylene), thickness of the individual layers, electron energy (0.1, 1.0 and 10.0 MeV) and angle of incidence between the electrons and the normal slab (0°, 30°, 60° and 90°). The cylindrical calculations were performed on finite and Infinite cylinders. The method used is similar to the one employed by Berger in his calculations of dose-depth curves in semi- infinite slabs. It takes into account energy losses from collisions with atomic electrons based on the continuous slowing-down model; it assumes a net angular denection at the end of each selected path length on the basis of the multiple scattering elastic theory of Goudsmit and Saunderson; and it employs a mean bremsstrahlung energy loss over each path length. The principal information derived from the study is the distribution of energy dissipated within the target as a function of position for target systems of practical interest to the radiation processor and principles for the most efficient utilization of electron beam sources. (author)
Particle resuspension from a multi-layer deposit by turbulent flow
International Nuclear Information System (INIS)
The aim of this work was to contribute to the understanding and quantification of particle resuspension from a bed exposed to a turbulent flow. The PARESS experiment has been set up and conducted. Multi-layer deposits of particles were created by allowing aerosols to settle on steel plates under conditions typical of a nuclear reactor containment following a severe accident. These were then exposed to a controlled turbulent airflow (U∞=5-25 m/s) in a wind tunnel and the evolution of the resuspension flux as a function of time was measured. The resuspension flux Fr decreased with exposure time to the airflow t, according to a power law Fr = a.t-b [kg/m2.s]. The parameters a and b depend on the flow velocity and the nature of the deposit. A new semi-empirical model, based on the comparison between the distributions of adhesive forces holding the particles on the deposit and aerodynamic forces tending to remove them, has been developed to simulate the stochastic nature of particle resuspension. This model is able to predict the experimentally observed decrease of the resuspension flux as a function of time and its dependence on flow velocity. Based on the results of the PARESS experiment, an empirical global relationship, which ignores the fine effects due to the nature of the different deposits, has been proposed. It appears that the resuspension flux is approximately proportinal to the cube of the flow velocity, and that a pseudo threshold velocity exists below which virtually no resuspension occurs. (author) 57 figs., 1 tab., 79 refs
Yu, Zhongbo; Liu, Di; Lü, Haishen; Fu, Xiaolei; Xiang, Long; Zhu, Yonghua
2012-12-01
SummaryHybrid data assimilation (DA) is greatly used in recent hydrology and water resources research. In this study, one newly introduced technique, the ensemble particle filter (EnPF), formed by coupling ensemble Kalman filter (EnKF) with particle filter (PF), is applied for a multi-layer soil moisture prediction in the Meilin watershed based on the support vector machines (SVMs). The data used in this paper includes six-layer soil moisture: 0-5 cm, 30 cm, 50 cm, 100 cm, 200 cm and 300 cm and five meteorological parameters: soil temperature at 5 cm and 20 cm, air temperature, relative humidity and solar radiation in the study area. In order to investigate this EnPF approach, another two filters, EnKF and PF are applied as another two data assimilation methods to conduct a comparison. In addition, the SVM model simulated data without updating with data assimilation technique is discussed as well to evaluate the data assimilation technique. Two experimental cases are explored here, one with 200 initial training ensemble members in the SVM training phase while the other with 1000 initial training ensemble members. Three main findings are obtained in this study: (1) the SVMs machine is a statistically sound and robust model for soil moisture prediction in both the surface and root zone layers, and the larger the initial training data ensemble, the more effective the operator derived; (2) data assimilation technique does improve the performance of SVM modeling; (3) EnPF outweighs the performance of other two filters as well as the SVM model; Moreover, the ability of EnPF and PF is not positively related to the resampling ensemble size, when the resampling size exceeds a certain amount, the performance of EnPF and PF would be degraded. Because the EnPF still performs well than EnKF, it can be used as a powerful data assimilation tool in the soil moisture prediction.
Multi-layered Cu/Si nanorods and its use for lithium ion batteries
International Nuclear Information System (INIS)
Highlights: • Cu/Si nanorods were deposited on Cu substrate via IA-OAD method. • High surface area, porosities and Cu presence improve the Si anode performance. • Subsequent depositions of Cu and Si enhance their interactions to form intermetallics. - Abstract: An ion assisted oblique angle (80°) electron beam deposition method was used to form well-aligned nanorods of a multi-layered Cu/Si film. For comparison, a flat multilayered Cu/Si film was coated at 0° angle using the same electron beam deposition system. The galvanostatic test results demonstrated that both electrodes performed better cycleability compared to bulk Si anode because the multilayer structure of the films enhanced the degree of atomic interactions between Cu and Si to form nano-sized intermetallics. Moreover, Cu buffered the mechanical stresses caused by lithiation and improved the electrical conductivity of the whole film which also affected the cycle life of the multilayered thin film anodes. Galvanostatic half-cell measurements showed that the Cu/Si film made of well aligned nanorods exhibited 1700 mA h g-1 as initial discharge capacity then it decreased to 500 mA h g-1 after 1st cycle (with 99% coulombic efficiency) and became stable for 100 cycles. The remarkable high coulombic efficiency, capacity retention and stable performance of the electrode are related to its unique structural morphology: the high surface area of nanorods increased the contact area of the anode with Li, decreased polarizations and enhanced mechanical resistance against volumetric changes due to the homogenously distributed nano-sized interspaces among them
Ryder, J.; Polcher, J.; Peylin, P.; Ottlé, C.; Chen, Y.; van Gorsel, E.; Haverd, V.; McGrath, M. J.; Naudts, K.; Otto, J.; Valade, A.; Luyssaert, S.
2016-01-01
In Earth system modelling, a description of the energy budget of the vegetated surface layer is fundamental as it determines the meteorological conditions in the planetary boundary layer and as such contributes to the atmospheric conditions and its circulation. The energy budget in most Earth system models has been based on a big-leaf approach, with averaging schemes that represent in-canopy processes. Furthermore, to be stable, that is to say, over large time steps and without large iterations, a surface layer model should be capable of implicit coupling to the atmospheric model. Surface models with large time steps, however, have difficulties in reproducing consistently the energy balance in field observations. Here we outline a newly developed numerical model for energy budget simulation, as a component of the land surface model ORCHIDEE-CAN (Organising Carbon and Hydrology In Dynamic Ecosystems - CANopy). This new model implements techniques from single-site canopy models in a practical way. It includes representation of in-canopy transport, a multi-layer long-wave radiation budget, height-specific calculation of aerodynamic and stomatal conductance, and interaction with the bare-soil flux within the canopy space. Significantly, it avoids iterations over the height of the canopy and so maintains implicit coupling to the atmospheric model LMDz (Laboratoire de Météorologie Dynamique Zoomed model). As a first test, the model is evaluated against data from both an intensive measurement campaign and longer-term eddy-covariance measurements for the intensively studied Eucalyptus stand at Tumbarumba, Australia. The model performs well in replicating both diurnal and annual cycles of energy and water fluxes, as well as the vertical gradients of temperature and of sensible heat fluxes.
A coupled atmosphere and multi-layer land surface model for improving heavy rainfall simulation
Directory of Open Access Journals (Sweden)
M. Haggag
2008-04-01
Full Text Available A multi-layer land surface model (SOLVEG is dynamically coupled to the non-hydrostatic atmospheric model (MM5 in order to represent better spatial variations and changes in land surface characteristics compared with the land surface parameterization schemes included in the MM5. In this coupling, calculations of the atmosphere and land surface models are carried out as independent tasks of different processors; a model coupler controls these calculations and data exchanges among models using Message Passing Interface (MPI. This coupled model is applied to the record-breaking heavy rain events occurred in Kyushu Island, the southernmost of Japan's main islands, from 20 July to 25 July in 2006. The test computations are conducted by using both the developed coupled model and the original land surface parameterization of MM5. The result of these computations shows that SOLVEG reproduce higher ground temperature than land surface parameterization schemes in the MM5. This result indicates the feedback of land surface processes between MM5 and SOLVEG plays an important role in the computation. The most pronounced difference is in the rainfall simulation that shows the importance of coupling SOLVEG and MM5. The coupled model accurately reproduces the heavy rainfall events observed in Kyushu Island compared to the original MM5 from both the spatial and temporal point of view. This paper clearly shows that realistic simulation of rainfall event strongly depends on land-surface processes interacting with cloud development that depends on surface heat and moisture fluxes, which in turn are mainly determined by land surface vegetation and soil moisture storage. Soil temperature/moisture changes significantly affect the localized precipitation and modest improvement in the land surface representation can enhance the heavy rain simulation. MM5-SOLVEG coupling shows a clear image of land surface-atmosphere interactions and the dynamic feedback on
International Nuclear Information System (INIS)
This paper investigates the photon tunneling and transmittance resonance through a multi-layer structure including a left-handed material(LHM). An analytical expression for the transmittance in a five-layer structure is given by the analytical transfer matrix method. The transmittance is studied as a function of the refractive index and the width of the LHM layer. The perfect photon tunneling results from the multi-layer structure, especially from the relation between the magnitude of the refractive index and the width of the LHM layer and those of the adjoining layers. Photons may tunnel through a much greater distance in this structure. Transmittance resonance happens, the peaks and valleys appear periodically at the resonance thickness. For an LHM with inherent losses, the perfect transmittance is suppressed. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)
Energy Technology Data Exchange (ETDEWEB)
Nazemnezhad, Reza, E-mail: rnazemnezhad@iust.ac.ir [School of Mechanical Engineering, Iran University of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of); Hosseini-Hashemi, Shahrokh [School of Mechanical Engineering, Iran University of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of); Center of Excellence in Railway Transportation, Iran University of Science and Technology, Narmak, Tehran (Iran, Islamic Republic of)
2014-09-12
Free vibration of cantilever multi-layer graphene nanoribbons (MLGNRs) with interlayer shear effect is investigated using molecular dynamics simulations (MD) and nonlocal elasticity. Because of similarity of MLGNRs to sandwich structures, sandwich formulations are expressed in the nonlocal form. By comparing the first two frequencies of MLGNRs with various layers and lengths obtained using MD simulations with those of the nonlocal sandwich formulation; the nonlocal parameter is calibrated to match the results of two methods. The results reveal that the calibrated nonlocal parameter for predicting the second frequencies is dependent on the number of MLGNR layers, and it increases by increasing the number of layers. - Highlights: • Nonlocal parameter is calibrated for vibration of multi-layer graphene nanoribbons. • Interlayer shear effect between GNR layers is also considered. • Two first nonlocal frequencies are obtained using sandwich formulation. • Molecular dynamics simulations are done for nonlocal parameter calibration.
Directory of Open Access Journals (Sweden)
J. Zhang
2013-04-01
Full Text Available The crystallization of polymers, caused by flow fields in the melt, has been the subject of extensive studies for many years. In this study, we use periodical shear to induce polypropylene to form multi-layer structure, which is usually observed in plants. Two interesting points were found: firstly, the quest of mimicking natural structures was achieved by controlled periodical shear field; secondly, the evolution from nano to shish-kebab-like cylindrite structure was obtained in the multi-layer structure, which can be clarified by nuclei competition model. This study can be used to better understand the shear-induced crystallization of polymer. Here our intention is to place this new observation on the map, leaving a fuller presentation and discussion of the work to a future publication.
Institute of Scientific and Technical Information of China (English)
GU Bo-hong; PAN Xiong-qi
2002-01-01
Rate-dependent property of material is very important in analysis of ballistic impact. The tensile property of Twaron(R) filaments at strain rate range from 0.01/s to1 000/s was obtained by MTS materials testing and split Hopkinson tension bar. Rate sensitivity of Twaron(R) filaments is discussed. Application of high strain rate property to ballistic perforation of multi- layered fabrics conforms to the actual situation than that of quasi-static property. The revised analytical model can be used to calculate the process of ballistic penetration and perforation on soft armour, such as fabric target plate,at intuitive approach and simple algorithm with a little computer process time. Predictions of the residual velocities and energy absorbed by the multi- layered fabric show good agreement with experimental data.
Institute of Scientific and Technical Information of China (English)
Weimin Zhang; Ping Zhang; Xuhui Deng; Chunyuan Zhang
2007-01-01
The aim of this paper is to apply the asymptotic homogenization method to determining analytically and numerically the transversely isotropic viscoelastic relaxation moduli of the equivalent particle for the intercalated multi-layer stack of intercalated type nanoplastics. A two-phase multilayered material containing n layers is considered. The matrix is assumed to be an isotropic viscoelastic standard linear body and the reinforcement is assumed to be an isotropic elastic body. Final explicit analytical formulae for the effective elastic moduli of the multilayered material are derived first; and then the correspondence principle is employed to obtain the homogenized relaxation moduli of the equivalent intercalated particle. A numerical example is given. Final explicit analytical formulae in the time domain derived here make it convenient to estimate the influence of all the particle parameters of micro-structural details on the effective properties of the equivalent intercalated particle. The results of this paper can also be applied to multi-layer composites.
International Nuclear Information System (INIS)
Free vibration of cantilever multi-layer graphene nanoribbons (MLGNRs) with interlayer shear effect is investigated using molecular dynamics simulations (MD) and nonlocal elasticity. Because of similarity of MLGNRs to sandwich structures, sandwich formulations are expressed in the nonlocal form. By comparing the first two frequencies of MLGNRs with various layers and lengths obtained using MD simulations with those of the nonlocal sandwich formulation; the nonlocal parameter is calibrated to match the results of two methods. The results reveal that the calibrated nonlocal parameter for predicting the second frequencies is dependent on the number of MLGNR layers, and it increases by increasing the number of layers. - Highlights: • Nonlocal parameter is calibrated for vibration of multi-layer graphene nanoribbons. • Interlayer shear effect between GNR layers is also considered. • Two first nonlocal frequencies are obtained using sandwich formulation. • Molecular dynamics simulations are done for nonlocal parameter calibration
International Nuclear Information System (INIS)
Zinc telluride (ZnTe) thin films have been deposited on glass/conducting glass substrates using a low-cost electrodeposition method. The resulting films have been characterized using various techniques in order to optimize growth parameters. X-ray diffraction (XRD) has been used to identify the phases present in the films. Photoelectrochemical (PEC) cell and optical absorption measurements have been performed to determine the electrical conductivity type, and the bandgap of the layers, respectively. It has been confirmed by XRD measurement that the deposited layers mainly consist of ZnTe phases. The PEC measurements indicate that the ZnTe layers are p-type in electrical conduction and optical absorption measurements show that their bandgap is in the range 2.10-2.20 eV. p-Type ZnTe window materials have been used in CdTe based solar cell structures, following new designs of graded bandgap multi-layer solar cells. The structures of FTO/ZnTe/CdTe/metal and FTO/ZnTe/CdTe/CdHgTe/metal have been investigated. The results are presented in this paper using observed experimental data
Energy Technology Data Exchange (ETDEWEB)
Nasedkina, A.A.; Nasedkin, A.V.; Iovane, G. [Southern Federal University, Rostov Na Donu (Russian Federation)
2009-07-15
The paper discusses modeling of a multi-layer coal seam under hydrodynamic action based on the coupled equations of poroelasticity and filtration with the nonlinear relationship of permeability and porous pressure. The calculations by the finite element method use correspondence between the poroelasticity and thermoelasticity equations. The influence of input data on the size of a degassing hole area is analyzed for the couple problem and pure filtration problem.
Baudron, Paul
2013-01-01
The Campo de Cartagena area in the Murcia region (SE Spain) is an emblematic case of the hydrological and environmental changes caused by the intensive use of groundwater for agriculture in semiarid Mediterranean areas. Agricultural development supported by the multi-layer aquifer system has led to the overexploitation of the deep layers, while irrigation return flow and the subsequent increased recharge rates increased water table levels in the unconfined layer. In addition, a large number o...
Lackner J. M.; Major B.; Waldhauser W.; Mzyk A.; Major Ł.; Kot M.
2015-01-01
Goal of this work is the investigation of roughness influences on the abrasive wear behaviour of magnetron sputtered multi-layered, low-friction coatings on carbon-fibre reinforced polymers (CFRP). Higher coating roughness at similar CFRP quality was realized by higher deposition rates, leading to increased heat flux to the substrates during deposition. Thermal expansion of the epoxy matrix on the micro scale results in a wavy, wrinkled surface topography. Both in scratch and reciprocal slidi...
Czech Academy of Sciences Publication Activity Database
Hutař, Pavel; Náhlík, Luboš; Šestáková, Lucie; Ševčík, Martin; Knésl, Zdeněk; Nezbedová, E.
2010-01-01
Roč. 92, č. 5 (2010), s. 1120-1125. ISSN 0263-8223 R&D Projects: GA ČR GA106/09/0279 Institutional research plan: CEZ:AV0Z20410507 Keywords : Protective layers * Multi-layer pipes damage * Fracture mechanics * Bi-material interface * Generalized stress intensity factor Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 2.028, year: 2010
Liu, Enru; Zhang, Z.; Yue, J.H.; Dobson, Andy
2008-01-01
We present a semi-analytic method based on the propagation matrix formulation of indirect boundary element method to compute response of elastic (and acoustic) waves in multi-layered media with irregular interfaces. The method works recursively starting from the top-most free surface at which a stress-free boundary condition is applied, and the displacement-stress boundary conditions are then subsequently applied at each interface. The basic idea behind this method is the matrix formulation o...
International Nuclear Information System (INIS)
We report a rigorous full dimensional quantum dynamics algorithm, the multi-layer Lanczos method, for computing vibrational energies and dipole transition intensities of polyatomic molecules without any dynamics approximation. The multi-layer Lanczos method is developed by using a few advanced techniques including the guided spectral transform Lanczos method, multi-layer Lanczos iteration approach, recursive residue generation method, and dipole-wavefunction contraction. The quantum molecular Hamiltonian at the total angular momentum J = 0 is represented in a set of orthogonal polyspherical coordinates so that the large amplitude motions of vibrations are naturally described. In particular, the algorithm is general and problem-independent. An application is illustrated by calculating the infrared vibrational dipole transition spectrum of CH based on the ab initio T8 potential energy surface of Schwenke and Partridge and the low-order truncated ab initio dipole moment surfaces of Yurchenko and co-workers. A comparison with experiments is made. The algorithm is also applicable for Raman polarizability active spectra
Micron-sized fracture experiments on amorphous SiOx films and SiOx/SiNx multi-layers
International Nuclear Information System (INIS)
In this study miniaturized monolithic cantilevers of thermally grown silicon oxide and multi-layer cantilevers of plasma enhanced chemical vapor deposited silicon oxide and nitride were mechanically characterized. In order to determine the fracture stress as well as the fracture toughness, un-notched and focused ion beam pre-notched cantilevers were tested. While the thickness of the monolithic cantilevers was varied from 280 nm to 2380 nm, the individual sub-layer thickness of the multi-layer cantilevers was adjusted to 50 nm. Bending experiments reveal a small increase of the fracture stresses with decreasing cantilever thicknesses. For the multi-layer stacks the tensile stress at fracture slightly exceeds the strength values of the corresponding monolithic materials. Furthermore, it is demonstrated that the specimens pre-notched by focused ion beam do not show significant changes in fracture toughness with varying pre-notch size. This makes the applied test a reproducible technique to determine fracture toughness of brittle films.
Micron-sized fracture experiments on amorphous SiOx films and SiOx/SiNx multi-layers
Energy Technology Data Exchange (ETDEWEB)
Matoy, Kurt, E-mail: Kurt.Matoy@k-ai.a [Kompetenzzentrum Automobil- und Industrie-Elektronik GmbH, A-9524 Villach (Austria); Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, A-8700 Leoben (Austria); Department Materials Physics, University of Leoben, A-8700 Leoben (Austria); Schoenherr, Helmut; Detzel, Thomas [Infineon Technologies Austria AG, A-9500 Villach (Austria); Dehm, Gerhard [Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, A-8700 Leoben (Austria); Department Materials Physics, University of Leoben, A-8700 Leoben (Austria)
2010-08-02
In this study miniaturized monolithic cantilevers of thermally grown silicon oxide and multi-layer cantilevers of plasma enhanced chemical vapor deposited silicon oxide and nitride were mechanically characterized. In order to determine the fracture stress as well as the fracture toughness, un-notched and focused ion beam pre-notched cantilevers were tested. While the thickness of the monolithic cantilevers was varied from 280 nm to 2380 nm, the individual sub-layer thickness of the multi-layer cantilevers was adjusted to 50 nm. Bending experiments reveal a small increase of the fracture stresses with decreasing cantilever thicknesses. For the multi-layer stacks the tensile stress at fracture slightly exceeds the strength values of the corresponding monolithic materials. Furthermore, it is demonstrated that the specimens pre-notched by focused ion beam do not show significant changes in fracture toughness with varying pre-notch size. This makes the applied test a reproducible technique to determine fracture toughness of brittle films.
Evaluation of ozone uptake by the rice canopy with the multi-layer model
International Nuclear Information System (INIS)
The stomatal conductance (gs) of rice leaves in vertical canopy layers was measured in both the ambient and FACE fields, where the concentration of ozone ([O3]) was elevated artificially, during the heading and flowering stages, 2007. The gs sub-model of rice was developed by a multiplicative approach with modifications of PAR, VPD, AOT40 and [O3], while the multi-layer model of the O3 uptake process in the rice canopy was developed by incorporating the gs sub-model. By the proposed model, vertical profiles of O3 fluxes on a single leaf (FO3) and in each canopy layer were calculated in the conditions 46.0, 40.2 and 43.6 ppb of [O3] at z = 280 cm at 1030, 1200 and 1530 h on August 30. O3 uptake by a single leaf (-FO3) in the upper canopy layer peaked at 1530 h and was smallest at 1200 h. The smallest-FO3 at 1200 h was caused not only by the lowest [O3] but also smaller gs, while the smaller gs at 1200 h was caused by smaller PAR on the flag leaf, even under the largest global solar radiation (SR) condition, because the leaf stands erect. The estimated O3 uptakes in the paddy field were 14.9, 13.7 and 12.1 (nmol/square m/s) at 1030, 1200 and 1530 h, respectively. The predicted F(O3) under different [O3] conditions by the model revealed that FO3 would exceed the threshold of -6 nmol/square m/s in more than 60 ppb [O3] at 1030 and 1200 h and in more than 50 ppb at 1530 h. The predicted FO3 under different SR conditions with fixed [O3] of 80 ppb revealed that FO3 would reach the threshold in more than 400 W/square m of SR at 1030 and 1200 h and more than 200 W/square m at 1530 h under this relatively high [O3] condition
International Nuclear Information System (INIS)
Highlights: ► A numerical method to study the heat transfer through a PCM composite wallboard is presented. ► PCM wallboard can reduce energy consumption and shift peak electricity load. ► There is an optimal location for the PCM wallboard in the building envelop. ► The PCM wallboard performance depends on weather conditions. - Abstract: Phase change materials (PCMs) have the capability to store/release massive latent heat when undergoing phase change. When impregnated or encapsulated into wallboard or concrete systems, PCMs can greatly enhance their thermal energy storage capacity and effective thermal mass. When used in the building envelope PCM wallboard has the potential to improve building operation by reducing the energy requirement for maintaining thermal comfort, downsizing the AC/heating equipment, and shifting the peak load from the electrical grid. In this work we numerically studied the potential of PCM on energy saving for residential homes. For that purpose we solved the one-dimensional, transient heat equation through the multi-layered building envelope using the Crank–Nicolson discretization scheme. A source term is incorporated to account for the thermal-physical properties of the composite PCM wallboard. Using this code we examined a PCM composite wallboard incorporated into the walls and roof of a typical residential building across various climate zones. The PCM performance was studied under all seasonal conditions using the latest typical meteorological year (TMY3) data for exterior boundary conditions. Our simulations show that PCM performance highly depends on the weather conditions, emphasizing the necessity to choose different PCMs at different climate zones. Comparisons were also made between different PCM wallboard locations. Our work shows that there exists an optimal location for PCM placement within building envelope dependent upon the resistance values between the PCM layer and the exterior boundary conditions. We further
Technical and Economic Viability of Ceramic Multi-Layer Composite SiC Cladding for LWRS
International Nuclear Information System (INIS)
The Ceramic Multi-layer Composite (CMC) cladding has been under investigation at MIT for many years. Recently, increasing focus has been given to the modelling and performance of the cladding under PWR conditions for traditional and advanced fuel designs. These designs include use of annular pellets to reduce the centreline fuel temperature while including additional free volume to accommodate fission gases. Another option considered is adding a small amount of BeO to improve the thermal conductivity of the fuel. The reactor physics of both of these options were analyzed and found to have similar behaviour to a core with zircaloy cladding. These options often come at the cost of higher enrichment requirements. A third option was the replacement of the helium with liquid lead-bismuth in the fuel-cladding gap to improve its thermal conductivity. If the average fuel temperature and plenum pressure are considered as figures of merit, the BeO fuel was seen as the best option among the three designs. The economic implication of investing in CMC cladding for the current US operating reactors to improve the accident tolerance of nuclear fuel is analyzed. The CMC cladding is the only option among the proposed accident tolerant fuel concepts in the US that could result in a fuel enrichment savings, thus compatible with current enrichment infrastructure. The CMC cladding could also result in additional economic benefit by avoiding the costs that might be incurred following a severe accident. However, due to its long development period and likely higher cost of manufacturing compared to zircaloy, its economics merits are uncertain. The significant role that thermal conductivity degradation and swelling induced irradiation plays in performance of CMC cladding has already been documented. However, the impact of material properties on the performance of the neighbouring layers has been underrated and found recently to be critical for the viability of the concept. The current
A general framework for multi-flow multi-layer multi-project reticles design
Kahng, Andrew B.; Xu, Xu
2006-10-01
The aggressive scaling of VLSI feature size and the pervasive use of advanced reticle enhancement technologies leads to dramatic increases in mask costs, pushing prototype and low volume production designs at the limit of economic feasibility. Multiple project wafers (MPW), or "shuttle" runs, provide an attractive solution for such designs, by providing a mechanism to share the cost of mask tooling among up to tens of designs of the same technology flow. However, delay cost associated with schedule alignment is ignored in previous work. The saving on mask cost may be easily surpassed by the profit loss due to the schedule alignment. Therefore, Multi- flow Multi-layer Multi-project Reticles (MFMLMPR) become a more viable mask-cost saving technique for low volume production since it share the mask cost between different layers of the same design and between designs of different technology flows. However, MFMLMPR design introduce complexities not encountered in traditional single-flow or single-layer reticles. In this paper we propose the first design flow for MFMLMPR aimed at minimizing the total manufacturing cost (including mask cost, wafer cost and delay cost) to fulfill given die production volumes. Our flow includes three main steps: (1) schedule-aware project partitioning with multi-flow embedding (2) multi-frame reticle design, and (3) multi-project frame floorplanning. Our contributions are as follows. For the first step, a fast iterative matching algorithm is proposed to calculate the mask cost for multi-flow embedding with consideration of all practical manufacturing costs. We then propose an integer linear programming (ILP) based method for optimal manufacturing cost minimization. Since ILP suffers from impractically long runtimes when the number of projects is large, we propose a sliding time window heuristic to exhaustively search the solution space for the best tradeoff between mask cost and delay cost. For the second step, we propose an ASAP frame
Micro-Satellite Impact Tests to Investigate Multi-Layer Insulation Fragments
Liou, J.C.; Murakami, Junko; Hanaha, Toshiya
2009-01-01
This paper summarizes two satellite impact experiments completed in 2008. The objective of the experiments is to investigate the physical properties of satellite fragments, including those originated from Multi-Layer Insulation (MLI) and solar panels. The ultimate goal is to use the results to improve the NASA Standard Breakup Model. The targets were two cubic micro-satellites, 20 cm by 20 cm by 20 cm in size, and approximately 1,500 g in mass. The main structure of each micro-satellite was composed of five layers; the top and bottom layers and three internal layers parallel to the top and bottom layers, plus four side panels. The top layer was equipped with solar cells that was mounted to an aluminum honeycomb sandwich panel with CFRP face sheets. The four side panels and the bottom layer are all covered with MLI. The two satellite impact experiments were conducted using the two-stage light gas gun at the Kyushu Institute of Technology in Kitakyusyu, Japan. For the first experiment (labeled Shot F), the satellite was oriented in such a way that the solar panel was facing the incoming projectile, a 39.3 g aluminum alloy solid sphere. For the second experiment (labeled Shot R), the satellite was oriented so that the solar panel was on the opposite side of the impact surface. The projectile used in the second shot was a 39.2 g aluminum alloy solid sphere. The impact speeds of Shot F and Shot R were 1.74 km/s and 1.78 km/s, respectively. The ratio of the impact kinetic energy to satellite mass for the two experiments was about 40 J/g. Both target satellites were completely fragmented, although there were noticeable differences in the characteristics of the fragments. Approximately 1,800 fragments were collected from Shot F but only 1,000 fragments were collected from Shot R. This difference primarily comes from the number of needle-like CFRP and MLI fragments. The difference in CFRP pieces depends on how the CFRP panels were fragmented. Regarding the MLI pieces, a
Braiding a Flock: Winding Statistics of Interacting Flying Spins
Caussin, Jean-Baptiste; Bartolo, Denis
2015-06-01
When animal groups move coherently in the form of a flock, their trajectories are not all parallel, the individuals exchange their position in the group. In this Letter, we introduce a measure of this mixing dynamics, which we quantify as the winding of the braid formed from the particle trajectories. Building on a paradigmatic flocking model we numerically and theoretically explain the winding statistics and show that it is predominantly set by the global twist of the trajectories as a consequence of a spontaneous symmetry breaking.
Braided embeddings of contact 3-manifolds in the standard contact 5-sphere
Etnyre, John B.; Furukawa, Ryo
2015-01-01
In this paper we study embeddings of contact manifolds using braidings of one manifold about another. In particular we show how to embed many contact 3-manifolds into the standard contact 5-sphere. We also show how to obstruct braidings of one manifold about another using contact geometry.
Tablet-woven and tabby-woven braids from the Czech late medieval archaeological findings
Czech Academy of Sciences Publication Activity Database
Březinová, Helena
2010-01-01
Roč. 23, - (2010), s. 47-51. ISSN 0860-0007 Institutional research plan: CEZ:AV0Z80020508 Keywords : textile fragments * tablet-woven braids * tabby-woven braids * late medieval Subject RIV: AC - Archeology, Anthropology, Ethnology
On the cohomology of spaces of links and braids via configuration space integrals
Volic, Ismar
2010-01-01
We study the cohomology of spaces of string links and braids in $\\mathbb{R}^n$ for $n\\geq 3$ using configuration space integrals. For $n>3$, these integrals give a chain map from certain diagram complexes to the deRham algebra of differential forms on these spaces. For $n=3$, they produce all finite type invariants of string links and braids.
Complete braided adsorbent for marine testing to demonstrate 3g-U/kg-adsorbent
Energy Technology Data Exchange (ETDEWEB)
Janke, Chris [ORNL; Yatsandra, Oyola [ORNL; Mayes, Richard [ORNL; none,; Gill, Gary [PNNL; Li-Jung, Kuo [PNNL; Wood, Jordana [PNNL; Sadananda, Das [ORNL
2014-04-30
ORNL has manufactured four braided adsorbents that successfully demonstrated uranium adsorption capacities ranging from 3.0-3.6 g-U/kg-adsorbent in marine testing at PNNL. Four new braided and leno woven fabric adsorbents have also been prepared by ORNL and are currently undergoing marine testing at PNNL.
Root profile in Multi-layered Dehesas: an approach to plant-to-plant Interaction
Rolo, V.; Moreno, G.
2009-04-01
Assessing plant-to-plant relationship is a key issue in agroforestry systems. Due to the sessile feature of plants most of these interactions take place within a restricted space, so characterizing the zone where the plant alters its environment is important to find overlapping areas where the facilitation or competition could occur. Main part of plan-to-plant interactions in the dehesa are located at belowground level, thus the main limited resources in Mediterranean ecosystems are soil nutrient and water. Hence a better knowledge of rooting plant profile can be useful to understand the functioning of the dehesa. The Iberian dehesa has always been considered as a silvopastoral system where, at least, two strata of vegetation coexist: native grasses and trees. However the dehesa is also a diverse system where cropland and encroached territories have been systematically combined, more or less periodically, with native pasture in order to obtain agricultural, pastoral and forestry outputs. These multipurpose mosaic-type systems generate several scenarios where the plant influence zone may be overlapped and the interaction, competition or facilitation, between plants can play an important role in the ecosystem functioning in terms of productivity and stability. In the present study our aim was to characterize the rooting profile of multi-layered dehesas in order to understand the competitive, and/or facilitative, relationships within the different plant strata. The root profile of Quercus ilex subsp. ballota, Cistus ladanifer, Retama spaherocarpa and natural grasses was studied. So 48 trenches, up to 2 meters deep, were excavated in 4 different environments: (i) grass; (ii) tree-grass; (iii) tree-shrub and (iv) tree-shrub-grass (12 trenches in each environment). The study was carried out in 4 dehesas, 2 encroached with C. ladanifer and 2 with R. spaherocarpa. In every trench soil samples were taken each 20 cm. Subsequently, all samples were sieved using different mesh
Theoretical studies on conformation comparison of braid-like and triplex DNA
Yang, Linjing; Bai, Chunli; Liu, Ciquan; Shi, Xiufan; Lee, Imshik
1999-03-01
Based on the experimental data of scanning tunneling microscopy (STM), models of three-stranded braid-like DNAs composed by three kinds of base triplets AAA, TAT and GCA were constructed. We investigated the braid-like DNAs and their comparative triplex DNAs using a molecular mechanics method. The three strands of braid-like DNAs are proven equivalent, while those of triplex DNAs are not. The conformational energies for braid-like DNAs were found to be higher than that for triplex DNAs. Each period in one strand of braid-like DNA has 18 nucleotides, half of which are right-handed, while the other half are left-handed. Additional discussions concerning sugar puckering modes and the H-bonds are also included.
Structure Design of the 3-D Braided Composite Based on a Hybrid Optimization Algorithm
Zhang, Ke
Three-dimensional braided composite has the better designable characteristic. Whereas wide application of hollow-rectangular-section three-dimensional braided composite in engineering, optimization design of the three-dimensional braided composite made by 4-step method were introduced. Firstly, the stiffness and damping characteristic analysis of the composite is presented. Then, the mathematical models for structure design of the three-dimensional braided composite were established. The objective functions are based on the specific damping capacity and stiffness of the composite. The design variables are the braiding parameters of the composites and sectional geometrical size of the composite. The optimization problem is solved by using ant colony optimization (ACO), contenting the determinate restriction. The results of numeral examples show that the better damping and stiffness characteristic could be obtained. The method proposed here is useful for the structure design of the kind of member and its engineering application.
Schultz, Alfred; Mund, Jan-Peter; Körner, Michael; Wilke, Robert
2015-01-01
Since two decades, the use of terrestrial laser scanning (TLS) and Airborne Light Detection and Ranging (LIDAR) has become very prominent in analysing 3D forest structures (AKAY et al. 2009). The potential of full waveform analysis of high density Airborne LiDAR data (ALS) for the detection and structural analysis of multi-layered forest stands is not yet well investigated (JASKIERNIAK et al. 2011), although ALS data provide exact information on tree heights of multi-layered forest stands usi...
International Nuclear Information System (INIS)
Copper oxide superconductors possess multi-layered structures with a layer sequence of -CuO2-(Q-CuO2)n-1-AO-(MO1±δ)m-AO- or -CuO2 -B-(O2 -B)s-1 -CuO2 -AO-(MO1±δ)m -AO- along the elongated c axis. Based on this layer sequence, the known copper oxide structures are categorized as members of the homologous series, MmArQn-1CunOm+r+2+n±δ (M-mr(n-1)n ; category A) or MmA2kBsCu1+kOm+4k+2s±δ (M-m(2k)s (1+k ); category B). Stabilization of such structures especially in the case of high values of the n /s parameter, i.e. the higher members of the homologous series, has been demonstrated to be apparently promoted under high pressures and/or strongly oxidizing conditions. Consequently, techniques for applying both high oxygen gas pressures (10-2000 atm) and ultra-high solid-medium pressures (2-8 GPa) have been advantageously utilized in synthesizing various superconductive copper oxide phases. Especially the ultra-high solid-medium pressure synthesis carried out in the so-called cubic-anvil/belt-type apparatus has proven to be extremely successful in synthesizing novel superconductive phases. In order to achieve high partial pressures of oxygen in the solid-medium environment, 'external' oxygen-generating oxides such as KClO4, KClO3 and Ag2O2 are commonly added to the precursor mixtures. It is emphasized that in some cases it is possible to utilize 'internal' oxidizing agents alone, i.e. highly oxidized precursors such as BaCuO2+δ and Ba2 Cu3 O5+δ containing metal constituents common with the desired copper oxide phase only. In the present paper, the potential and applications of high-pressure techniques in synthesizing multi-layered copper oxides and related structures are reviewed and discussed with emphasis on the important 'historical' discoveries of novel phases and the present status of controlled production of high-quality samples of such phases. (author)
A pseudo genetic model of coarse braided-river deposits
Pirot, Guillaume; Straubhaar, Julien; Renard, Philippe
2015-12-01
A new method is proposed to produce three-dimensional facies models of braided-river aquifers based on analog data. The algorithm consists of two steps. The first step involves building the main geological units. The production of the principal inner structures of the aquifer is achieved by stacking Multiple-Point-Statistics simulations of successive topographies, thus mimicking the major successive flooding events responsible for the erosion and deposition of sediments. The second step of the algorithm consists of generating fine scale heterogeneity within the main geological units. These smaller-scale structures are generated by mimicking the trough-filling process occurring in braided rivers; the imitation of the physical processes relies on the local topography and on a local approximation of the flow. This produces realistic cross-stratified sediments, comparable to what can be observed in outcrops. The three main input parameters of the algorithm offer control over the proportions, the continuity and the dimensions of the deposits. Calibration of these parameters does not require invasive field measurements and can rely partly on analog data.
High temperature braided rope seals for static sealing applications
Adams, Michael L.; Olsen, Andrew; Darolia, Ram; Steinetz, Bruce M.; Bartolotta, Paul A.
1996-01-01
Achieving efficiency and performance goals of advanced aircraft and industrial systems are leading designers to implement high temperature materials such as ceramics and intermetallics. Generally these advanced materials are applied selectively in the highest temperature sections of the engine system including the combustor and high pressure turbine, amongst others. Thermal strains that result in attaching the low expansion-rate components to high expansion rate superalloy structures can cause significant life reduction in the components. Seals are being designed to both seal and to serve as compliant mounts allowing for relative thermal growths between high temperature but brittle primary structures and the surrounding support structures. Designers require high temperature, low-leakage, compliant seals to mitigate thermal stresses and control parasitic and cooling airflow between structures. NASA is developing high temperature braided rope seals in a variety of configurations to help solve these problems. This paper will describe the types of seals being developed, describe unique test techniques used to assess seal performance, and present leakage flow data under representative pressure, temperature and scrubbing conditions. Feasibility of the braided rope seals for both an industrial tube seal and a turbine vane seal application is also demonstrated.
Braided affine geometry and q-analogs of wave operators
International Nuclear Information System (INIS)
The main goal of this review is to compare different approaches to constructing the geometry associated with a Hecke type braiding (in particular, with that related to the quantum group Uq(sl(n))). We place emphasis on the affine braided geometry related to the so-called reflection equation algebra (REA). All objects of such a type of geometry are defined in the spirit of affine algebraic geometry via polynomial relations on generators. We begin by comparing the Poisson counterparts of 'quantum varieties' and describe different approaches to their quantization. Also, we exhibit two approaches to introducing q-analogs of vector bundles and defining the Chern-Connes index for them on quantum spheres. In accordance with the Serre-Swan approach, the q-vector bundles are treated as finitely generated projective modules over the corresponding quantum algebras. Besides, we describe the basic properties of the REA used in this construction and compare different ways of defining q-analogs of partial derivatives and differentials on the REA and algebras close to them. In particular, we present a way of introducing a q-differential calculus via Koszul type complexes. The elements of the q-calculus are applied to defining q-analogs of some relativistic wave operators. (topical review)
Directory of Open Access Journals (Sweden)
Lackner J.M.
2015-09-01
Full Text Available Goal of this work is the investigation of roughness influences on the abrasive wear behaviour of magnetron sputtered multi-layered, low-friction coatings on carbon-fibre reinforced polymers (CFRP. Higher coating roughness at similar CFRP quality was realized by higher deposition rates, leading to increased heat flux to the substrates during deposition. Thermal expansion of the epoxy matrix on the micro scale results in a wavy, wrinkled surface topography. Both in scratch and reciprocal sliding testing against alumina, the friction coefficients are lower for the smooth coatings, but their wear rate is higher due to low-cycle fatigue caused abrasion.
International Nuclear Information System (INIS)
This paper presents the correlation between the experimental and code results of three-dimensional multi-layer brick arrays. These arrays consisted of one, two or four layers of fuel bricks, and three, five or nine layers of interstitial bricks respectively. They were excited using sine-sweep, sine-dwell or earthquake motion applied in the X axis. The sensitivity of brick response to various code input parameters is also presented. Experimental/code results were compared in terms of velocities, forces and resonant frequencies. Correlation criteria and error analysis techniques have been discussed previously
A combined SEM, CV and EIS study of multi-layered porous ceramic reactors for flue gas purification
DEFF Research Database (Denmark)
He, Zeming; Andersen, Kjeld Bøhm; Nygaard, Frederik Berg; Kammer Hansen, Kent
2013-01-01
The effect of sintering temperature of 12-layered porous ceramic reactors (comprising 5 cells) was studied using scanning electron microscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The difference in microstructures of the reactors was evaluated by SEM....... Additional information on the influence of sintering temperature on the properties of the reactors could be gained by the use of EIS. The present work has provided the first set of fundamental electrochemical data and their interpretation in terms of fabrication conditions, for the multi-layered porous...... ceramic reactors....
International Nuclear Information System (INIS)
This paper presents the thermo-mechanical response of multi-layered G-11 woven glass/epoxy laminates with internal and/or edge cracks under tensile loading at cryogenic temperatures obtained from a two-dimensional finite element analysis. A condition of generalized plane strain is assumed to exist in the composite. Cracks are considered to occur in the transverse fiber bundles and extend through the entire thickness of the fiber bundles. The finite element model accounts for the temperature-dependent constituent properties. A detailed examination of the Young's modulus and stress distributions near the crack tip is carried out which provides insight into material behavior at cryogenic temperatures
Development of SiPM-based scintillator tile detectors for a multi-layer fast neutron tracker
Jakubek J.; Uher J.; Prokopovich D.; Preston R.
2012-01-01
We are developing thin tile scintillator detectors with silicon photomultiplier (SiPM) readout for use in a multi-layer fast-neutron tracker. The tracker is based on interleaved Timepix and plastic scintillator layers. The thin 15 × 15 × 2 mm plastic scintillators require suitable optical readout in order to detect and measure the energy lost by energetic protons that have been recoiled by fast neutrons. Our first prototype used dual SiPMs, coupled to opposite edges of the scintillator tile u...
Energy Technology Data Exchange (ETDEWEB)
Wildschut, J. [Praktijkonderzoek Plant en Omgeving PPO, Wageningen UR, Lisse (Netherlands); Campen, J.C. (Glastuinbouw, Wageningen UR, Wageningen (Netherlands)
2010-11-15
Next to possible benefits such as improved greenhouse utilization, resulting in a lower cost price and production expansion without expanding the greenhouse, multi-layer heating (in the greenhouse and/or cell) offers significant opportunities to reduce the energy use in the forcing process [Dutch] Naast mogelijke voordelen als een betere kasbenutting, waardoor een lagere kostprijs, en productieuitbreiding zonder kasuitbreiding, biedt het broeien in meerdere lagen (in de kas en/of in de cel) grote mogelijkheden om het energieverbruik in de broeierij terug te dringen.
Scattering from a Multi-Layered Sphere Located in a High-Order Hermite-Gaussian Beam
Institute of Scientific and Technical Information of China (English)
LI Hai-Ying; WU Zhen-Sen; LI Zheng-Jun
2009-01-01
Scattering of a high-order Hermite-Gaussian beam by a multi-layered sphere is analyzed.The incident highorder Hermite-Gaussian beam field is expressed by the complex-source-point method and expanded in terms of spherical vector wave functions.The beam shape coefficients of the Hermite-Gaussian beam are obtained.Under electromagnetic field boundary conditions, coefficients is the expressions of scattering fields are derived.Results of the numerical calculation of scattering intensity axe presented.The effects of the particle parameters and beam parameters on scattering intensity are discussed in detail.
Rotunno, E.; Fabbri, F.; Cinquanta, E.; Kaplan, D.; Longo, M.; Lazzarini, L.; Molle, A.; Swaminathan, V.; Salviati, G.
2016-06-01
MoS2 multi-layer flakes, exfoliated from geological molybdenite, have been exposed to high dose electron irradiation showing clear evidence of crystal lattice and stoichiometry modifications. A massive surface sulfur depletion is induced together with the consequent formation of molybdenum nanoislands. It is found that a nanometric amorphous carbon layer, unwillingly deposited during the transmission electron microscope experiments, prevents the formation of the nanoislands. In the absence of the carbon layer, the formation of molybdenum grains proceeds both on the top and bottom surfaces of the flake. If carbon is present on both the surfaces then the formation of Mo grains is completely prevented.
Enhanced Inter-Cell Interference Coordination in Co-Channel Multi-Layer LTE-Advanced Networks
DEFF Research Database (Denmark)
Pedersen, Klaus I.; Wang, Yuanye; Strzyz, Stanislav; Frederiksen, Frank
2013-01-01
Different technical solutions and innovations are enabling the move from macro-only scenarios towards heterogeneous networks with a mixture of different base station types. In this article we focus on multi-layer LTE-Advanced networks, and especially address aspects related to interference...... management. The network controlled time-domain enhanced inter-cell interference coordination (eICIC) concept is outlined by explaining the benefits and characteristics of this solution. The benefits of using advanced terminal device receiver architectures with interference suppression capabilities are...
International Nuclear Information System (INIS)
In this paper, space charge in a multi-layer oil-paper insulation system was investigated using the pulsed electroacoustic (PEA) technique. A series of measurements had been carried following subjection of the insulation system to different applied voltages and different temperatures. Charge behaviours in the insulation system were analyzed and the influence of temperature on charge dynamics was discussed. The test results shows that homocharge injection takes place under all the test conditions, the applied DC voltage mainly affects the amount of space charge, while the temperature has greater influence on the distribution and mobility of space charge inside oil-paper samples.
Institute of Scientific and Technical Information of China (English)
QU Zhaoming; WANG Qingguo; LEI Yisan; ZHANG Ruigang
2013-01-01
To develop electromagnetic protection composites with integrated structure-function properties,the three-dimension (3D) braided nickel plated carbon fiber/epoxy resin (Ni-CF3D/EP) composites were prepared based on 3D five-directional braiding,unitary nickel plating and mold compression shaping.The electromagnetic protection properties of Ni-CF3D/EP composites including shielding effectiveness (SE) and reflection loss against plane electromagnetic wave,shielding properties against electromagnetic pulse (EMP) were investigated.The test results show that the novel composites have good electromagnetic protection properties in a wide frequency range of 14 kHz～ 18 GHz with SE of 42 dB～95 dB,the absorption bandwidth of-5 dB in 2 GHz～ 18 GHz can reach 10 GHz and the pulse peak SE against EMP is 43.7 dB which can reduce the electromagnetic energy greatly.Meanwhile,the mechanic properties were also investigated and the results indicate that the Ni-CF3D/EP composites can replace metal materials for loading-bearing structural applications because of their excellent mechanic properties.
Energy Technology Data Exchange (ETDEWEB)
Shinyama, Y., E-mail: y083818@edu.imc.tut.ac.jp [Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Yamaji, T.; Hatsukade, Y. [Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Takai, Y.; Aly-Hassan, M.S.; Nakai, A.; Hamada, H. [Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585 (Japan); Tanaka, S. [Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan)
2011-11-15
We applied a current-injection-based NDE method using a HTS-SQUID gradiometer to a braided CFRP with artificial cracks. Current distributions in the braided CFRP were estimated from measured field gradient distributions. A small crack, in which a few carbon-fiber bundles were cut, was well detected from the current distributions. A cross-section of the CFRP showed that a density of the bundles at edges is higher than the other part. The experimental results demonstrated the capability of the method to detect sub-mm cracks. Braided carbon fiber reinforced plastics (CFRPs) are one of multifunctional materials with superior properties such as mechanical strength to normal CFRPs since the braided CFRPs have continuous fiber bundles. In this paper, we applied the current-injection-based nondestructive evaluation (NDE) method using a HTS-SQUID gradiometer to the braided CFRP for the detection of the breakage of the bundles. We prepared planar braided CFRP samples with and without artificial cracks of 1 and 2 mm lengths, and measured the current density distribution above the samples using the NDE method. In the measurement results, not only a few completely-cut bundles but also the additional partially-cut bundles were detected from decrease in the measured current density along the cut bundle around the cracks. From these results, we showed that it is possible to inspect a few partially-cut bundles in the braided CFRPs by the NDE method.
Parametric instability of a many point-vortex system in a multi-layer flow under linear deformation
Ryzhov, Eugene A.; Koshel, Konstantin V.
2016-05-01
The paper deals with a dynamical system governing the motion of many point vortices located in different layers of a multi-layer flow under external deformation. The deformation consists of generally independent shear and rotational components. First, we examine the dynamics of the system's vorticity center. We demonstrate that the vorticity center of such a multi-vortex multi-layer system behaves just like the one of two point vortices interacting in a homogeneous deformation flow. Given nonstationary shear and rotational components oscillating with different magnitudes, the vorticity center may experience parametric instability leading to its unbounded growth. However, we then show that one can shift to a moving reference frame with the origin coinciding with the position of the vorticity center. In this new reference frame, the new vorticity center always stays at the origin of coordinates, and the equations governing the vortex trajectories look exactly the same as if the vorticity center had never moved in the original reference frame. Second, we studied the relative motion of two point vortices located in different layers of a two-layer flow under linear deformation. We analyze their regular and chaotic dynamics identifying parameters resulting in effective and extensive destabilization of the vortex trajectories.
Wincheski, Russell A.
2008-01-01
Thick, multi-layer aluminum structure has been widely used in aircraft design in critical wing splice areas. The multi-layer structure generally consists of three or four aluminum layers with different geometry and varying thickness, which are held together with fasteners. The detection of cracks under fasteners with ultrasonic techniques in subsurface layers away from the skin is impeded primarily by interlayer bonds and faying sealant condition. Further, assessment of such sealant condition is extremely challenging in terms of complexity of structure, limited access, and inspection cost. Although Eddy current techniques can be applied on in-service aircraft from the exterior of the skin without knowing sealant condition, the current eddy current techniques are not able to detect defects with wanted sensitivity. In this work a series of low frequency eddy current probes have been designed, fabricated and tested for this application. A probe design incorporating a shielded magnetic field sensor concentrically located in the interior of a drive coil has been employed to enable a localized deep diffusion of the electromagnetic field into the part under test. Due to the required low frequency inspections, probes have been testing using a variety of magnetic field sensors (pickup coil, giant magneto-resistive, anisotropic magneto-resistive, and spin-dependent tunneling). The probe designs as well as capabilities based upon a target inspection for sub-layer cracking in an airframe wing spar joint is presented.
International Nuclear Information System (INIS)
The hydrostatic equilibrium of multi-layer bodies lacks a satisfactory theoretical treatment despite its wide range of applicability. Here we show that by using the exact analytical potential of homogeneous ellipsoids we can obtain recursive analytical solutions and an exact numerical method for the hydrostatic equilibrium shape problem of multi-layer planets and synchronous moons. The recursive solutions rely on the series expansion of the potential in terms of the polar and equatorial shape eccentricities, while the numerical method uses the exact potential expression. These solutions can be used to infer the interior structure of planets and synchronous moons from their observed shape, rotation, and gravity. When applied to the dwarf planet Ceres, we show that it is most likely a differentiated body with an icy crust of equatorial thickness 30-90 km and a rocky core of density 2.4-3.1 g cm–3. For synchronous moons, we show that the J 2/C 22 ≅ 10/3 and the (b – c)/(a – c) ≅ 1/4 ratios have significant corrections of order Ω2/(πGρ), with important implications for how their gravitational coefficients are determined from fly-by radio science data and for how we assess their hydrostatic equilibrium state.
Stone, J. G.; Schleicher, R.; Deck, C. P.; Jacobsen, G. M.; Khalifa, H. E.; Back, C. A.
2015-11-01
Silicon carbide (SiC) fiber, SiC matrix composites (SiC/SiC) are being considered as a cladding material for light water reactors in order to improve safety performance. Engineered, multi-layer cladding designs consisting of both monolithic SiC (mSiC) and SiC/SiC have been examined as promising concepts to meet both strength and impermeability requirements. A new model has been developed to calculate stresses and failure probabilities for multi-layer cladding consisting of SiC-based materials in reactor operating conditions. The results show that stresses in SiC-based cladding are dominated by temperature-dependent irradiation-induced swelling, with the largest stresses occurring during the cold shutdown conditions. Failure probabilities are driven by the resulting tensile stresses at the cladding inner wall, while the outer wall is subject to compressive stresses. This indicates that the inner SiC/SiC, outer mSiC concept has the lowest failure probability, as the pseudo-plastic deformation of the composite reduces tensile loading and the compressed monolith provides a reliable, impermeable barrier to fission product release.
International Nuclear Information System (INIS)
In this work, the analytical discrete-ordinates (ADO) method is applied to radiative transfer with polarization in a multi-layer dielectric medium subject to Fresnel boundary/interface conditions and uniform external illumination by obliquely incident parallel rays. A general form of the phase matrix and arbitrary scattering order are allowed in each layer and a recently developed procedure based on a nascent delta function is used to model the polar-angle dependence of the incident beam. A generalization of Chandrasekhar's classical approach of a decomposition into unscattered and scattered problems and a subsequent Fourier decomposition of the scattered problem are developed. The resulting set of azimuthally independent problems is solved with the ADO method. Numerical results of benchmark quality are reported in tabular form for two test cases, one of which consists of a nine-layer system. -- Highlights: ► Polarized radiative transfer in multi-layer media with Fresnel interfaces is studied. ► The analytical discrete-ordinates method is used to find a solution to the problem. ► Numerical results of benchmark quality are tabulated for two test cases.
Measurements of the apparent thermal conductivity of multi-layer insulation between 20 K and 90 K
International Nuclear Information System (INIS)
NASA has the need to efficiently store cryogenic propellants in space for long periods of time. One method to improve storage efficiency is to use multi-layer insulation (MLI), a technique that minimizes the boiling rate due to radiation heat transfer. Typically, the thermal performance of MLI is determined by measuring the rate of evaporation of liquid nitrogen from a calibrated cryostat. The main limitation with this method is that testing conditions are restricted by the boiling temperature of the LN2, which may not match the requirements of the application. The Multi-Layer Insulation Thermal Conductivity Experiment (MIKE) at the National High Magnetic Field Laboratory is capable of measuring the effective thermal conductivity of MLI at variable boundary temperatures. MIKE uses cryo-refrigerators to control boundary temperatures in the calorimeter and a calibrated thermal link to measure the heat load. To make the measurements requested by NASA, MIKE needed to be recalibrated for the 20 K to 90 K range. Also, due to the expectation of a lower heat transfer rate, the heat load support rod material was changed to one with a lower thermal conductivity to ensure the temperature difference seen on the cold rod could be measurable at the estimated heat load. Presented are the alterations to MIKE including calibration data and heat load measurements on new load-bearing MLI supplied by NASA
Evaluation of multi-layered hardness in ion-irradiated stainless steel by nano-indentation technique
Energy Technology Data Exchange (ETDEWEB)
Oka, Hiroshi, E-mail: hiroshi_oka@eng.hokudai.ac.jp; Sato, Yutaka; Hashimoto, Naoyuki; Ohnuki, Somei
2015-07-15
Depth dependence of hardness in ion-irradiated 316 stainless steel was evaluated by the sectioning of damaged region and subsequent nano-indentation. The range of plastically deformed region by the nano-indentation was supplementarily investigated by transmission electron microscopy. When the indentation depth was the critical indentation depth, h{sub c}, which was derived from the Nix–Gao plot, the dislocation structure was observed from the specimen surface to right below the bottom of the ion-irradiated region. To verify the depth dependence of hardness, the “multi-layer model” was introduced in this study. The multi-layer model is based on the following assumptions; (1) the ion-irradiated region can be divided into sub-layers having their own local hardness, H{sub L}; (2) the hardness can be the product of f and H{sub L} in each sub-layer where f is the volume fraction of a deformation zone; and (3) the deformation zone can be a hemisphere. Eventually, through the sectioning and following nano-indentation, H{sub L} in each sub-layer was experimentally evaluated. Further the correlation between the displacement damage and the irradiation hardening ΔH in this study agreed with that of neutron irradiation experiments.
Evaluation of multi-layered hardness in ion-irradiated stainless steel by nano-indentation technique
International Nuclear Information System (INIS)
Depth dependence of hardness in ion-irradiated 316 stainless steel was evaluated by the sectioning of damaged region and subsequent nano-indentation. The range of plastically deformed region by the nano-indentation was supplementarily investigated by transmission electron microscopy. When the indentation depth was the critical indentation depth, hc, which was derived from the Nix–Gao plot, the dislocation structure was observed from the specimen surface to right below the bottom of the ion-irradiated region. To verify the depth dependence of hardness, the “multi-layer model” was introduced in this study. The multi-layer model is based on the following assumptions; (1) the ion-irradiated region can be divided into sub-layers having their own local hardness, HL; (2) the hardness can be the product of f and HL in each sub-layer where f is the volume fraction of a deformation zone; and (3) the deformation zone can be a hemisphere. Eventually, through the sectioning and following nano-indentation, HL in each sub-layer was experimentally evaluated. Further the correlation between the displacement damage and the irradiation hardening ΔH in this study agreed with that of neutron irradiation experiments
Wang, Huaping; Liu, Wanqiu; Zhou, Zhi
2014-03-01
The large span and heterogeneous components of multi-layered pavement structure usually bring about stochastic damage, and many modern approaches, such as ground penetrating radar, integral imaging and optical fiber sensing technology, have been employed to detect the degeneration mechanism. Restricted by the cost and universality, novel elements for pavement monitoring are in high demand. Optical fiber sensing technology for high sensitivity, long stability, anti-corrosion and resistance to water erosion then is considered. Therefore, a movable FBG sensor located in flexible pipe is developed, which has long stroke inside inner wall of the hollow pipe, and a full-scale shape of the structure could be sketched just with one FBG. Theoretical and experimental methods about establishing the relationship between wavelength variable and curvature have been provided, and function about reconfiguring the coordinate is converted to a mathematic question. Move over, transfer error modification has been taken into account for modify related error. Multi-layered pavement model embedded with this sensor will be accomplished to inspect its performance in later work. The work in the paper affords a feasible method for shape monitoring and would be potentially valuable for the maintenance and inverse design of pavement structure.
Alterations in braided rivers' morphology: a typology for Curvature Subcarpathians (Romania)
Ioana-Toroimac, Gabriela; Zaharia, Liliana; Ciobotaru, Nicu
2015-04-01
The morphology of braided rivers was altered by human pressures in the last century in Europe. Rivers from Curvature Subcarpathians have the highest sediment charges in Romania, therefore it seems relevant to evaluate the status of their braided sectors. Therefore, the aim of this work is to carry out an inventory of river morphology alterations suffered by braided rivers in Curvature Subcarpathians and to establish a typology based on indicators for channel adjustments and artificiality. For channel adjustments, we calculated the length of the braided sectors, the width of the active-channels and the length of banks covered by a riparian forest for 1900-2011 interval, in GIS. For artificiality, we counted dams, weirs, bridges, as well as artificial banks length for 2011 time horizon. The results indicate a diminishing braiding activity: all the rivers narrowed their braided active-channel (30-70% of the mean width); the majority suffered fluvial metamorphosis, transforming partially into single channels (0-75% of the braided sector length in 1900); artificial banks vary from 0 to 40% of the initial braided sector. We distinguished three main types of braided rivers based on morphological alterations. Type 1 includes rivers with human interventions and important braiding retraction, both upstream and downstream; a sub-type characterises by riparian forest lining the downstream metamorphosed reach; most rivers are in the south-western part of the studied region; the most demonstrative examples are Prahova and Ialomiţa rivers. Type 2 corresponds to rivers with important retraction upstream, without important values of artificiality; most demonstrative is Râmna River. Type 3 regroups rivers with a low level of channel adjustments and artificiality; actually, they had and still have the highest braiding activity in the studied region; they are located in the north-eastern part; typical examples are Putna and Şuşiţa rivers. As a discussion, the variations of active
Hom-Hopf group coalgebras and braided T-categories obtained from Hom-Hopf algebras
You, Miman; Zhou, Nan; Wang, Shuanhong
2015-11-01
The main aim of this paper is to provide new examples of braided T-categories in the sense of Turaev [Arabian J. Sci. Eng., Sect. C 33(2C), 483-503 (2008)]. For this purpose, we first introduce a class of new twisted Yetter-Drinfeld modules categories. Then, we construct a new braided T-category, generalizing the main constructions by Panaite and Staic [Isr. J. Math. 158, 349-366 (2007)]. Finally, we show that the new braided T-category in some conditions coincides with the representations of a certain Hom-Hopf group-coalgebra that we construct.
Factorization of differential expansion for antiparallel double-braid knots
Morozov, A
2016-01-01
Continuing the quest for exclusive Racah matrices, which are needed for evaluation of colored arborescent-knot polynomials in Chern-Simons theory, we suggest to extract them from a new kind of a double-evolution -- that of the antiparallel double-braids, which is a simple two-parametric family of two-bridge knots, generalizing the one-parametric family of twist knots. In the case of rectangular representations $R=[r^s]$ we found an evidence that the corresponding differential expansion miraculously factorizes and can be obtained from that for the twist knots. This reduces the problem of rectangular exclusive Racah to constructing the answers for just a few twist knots. We develop a recent conjecture on the structure of differential expansion for the simplest members of this family -- the trefoil and the figure-eight knot,-- but manage to guess the full answer only for contributions of single-floor pyramids. One step still remains to be done.
S-duality wall of SQCD from Toda braiding
Floch, Bruno Le
2015-01-01
S-duality domain walls couple quarks of a four-dimensional $N=2$ theory on one side of the wall to monopoles on the other side. This paper describes the S-duality wall of SU(N) SQCD with 2N hypermultiplets in terms of fields on the defect, namely three-dimensional $N=2$ SQCD with gauge group U(N-1) and 2N fundamental and 2N antifundamental chiral multiplets. The theory is found through the AGT correspondence by computing the braiding kernel of two semi-degenerate vertex operators in the Toda CFT. This three-dimensional theory is a limit of a USp(2N-2) gauge theory whose four-dimensional lift is self-dual, a situation reminiscent of how the theory T[G] on the S-duality wall of $N=4$ super Yang-Mills is self-mirror.
Systematically Generated Two-Qubit Braids for Fibonacci Anyons
Zeuch, Daniel; Carnahan, Caitlin; Bonesteel, N. E.
We show how two-qubit Fibonacci anyon braids can be generated using a simple iterative procedure which, in contrast to previous methods, does not require brute force search. Our construction is closely related to that of, but with the new feature that it can be used for three-anyon qubits as well as four-anyon qubits. The iterative procedure we use, which was introduced by Reichardt, generates sequences of three-anyon weaves that asymptotically conserve the total charge of two of the three anyons, without control over the corresponding phase factors. The resulting two-qubit gates are independent of these factors and their length grows as log 1/ ɛ, where ɛ is the error, which is asymptotically better than the Solovay-Kitaev method.
Yarn carrier apparatus for braiding machines and the like
El-Shiekh, Aly (Inventor); Li, Wei (Inventor); Hammad, Mohamed (Inventor)
1992-01-01
A yarn carrier apparatus particularly suited for use in braiding machinery or the like due to its capability of continuous yarn feeding and retraction of long lengths of yarn. The yarn carrier apparatus comprises a yarn supply spool which is rotatably mounted within the housing, a spring motor also mounted within the housing and operatively connected to the yarn supply spool through a mechanical transmission assembly which is adapted to multiply rotational movement between the first element of the gear assembly operatively connected to the spring motor and the final element of the gear assembly operatively connected to the yarn supply spool. The spring motor is adapted to tension the yarn during both feeding and retraction thereof, and it is further adapted to periodically rotatably slip within the housing and partially unwind so as to allow for continuous withdrawal of a long length of yarn without the spring motor becoming fully wound and preventing further yarn retraction.
Two dimensional hydrodynamic modeling of a high latitude braided river
Humphries, E.; Pavelsky, T.; Bates, P. D.
2014-12-01
Rivers are a fundamental resource to physical, ecologic and human systems, yet quantification of river flow in high-latitude environments remains limited due to the prevalence of complex morphologies, remote locations and sparse in situ monitoring equipment. Advances in hydrodynamic modeling and remote sensing technology allow us to address questions such as: How well can two-dimensional models simulate a flood wave in a highly 3-dimensional braided river environment, and how does the structure of such a flood wave differ from flow down a similar-sized single-channel river? Here, we use the raster-based hydrodynamic model LISFLOOD-FP to simulate flood waves, discharge, water surface height, and velocity measurements over a ~70 km reach of the Tanana River in Alaska. In order to use LISFLOOD-FP a digital elevation model (DEM) fused with detailed bathymetric data is required. During summer 2013, we surveyed 220,000 bathymetric points along the study reach using an echo sounder system connected to a high-precision GPS unit. The measurements are interpolated to a smooth bathymetric surface, using Topo to Raster interpolation, and combined with an existing five meter DEM (Alaska IfSAR) to create a seamless river terrain model. Flood waves are simulated using varying complexities in model solvers, then compared to gauge records and water logger data to assess major sources of model uncertainty. Velocity and flow direction maps are also assessed and quantified for detailed analysis of braided channel flow. The most accurate model output occurs with using the full two-dimensional model structure, and major inaccuracies appear to be related to DEM quality and roughness values. Future work will intercompare model outputs with extensive ground measurements and new data from AirSWOT, an airborne analog for the Surface Water and Ocean Topography (SWOT) mission, which aims to provide high-resolution measurements of terrestrial and ocean water surface elevations globally.
International Nuclear Information System (INIS)
The application of fast neutron absorption in non-destructive testing of materials and products is considered. Fast neutron transfer in multilayer objects with variable thickness of separate layers and in objects with a local inhomogeneity (defect) is studied theoretically and experimentally. The operation of radiometric absorption flow detector in analogous regime is considered. Defectograms of the testing of mono- and multilayer products are presented
International Nuclear Information System (INIS)
Tic/Ti(C,N)/TiN multi-layer coatings are prepared on the 1Cr13 stainless steel substrate by the technique of Chemical Vapour Deposition, and the fretting wear behaviour of 1Cr13 stainless steel and TiC/Ti(C,N)/TiN coatings are investigated and studied controversially from 25 degree C to 400 degree C in the gross slip regime. It shows that the temperature has great influence on the fretting wear in the gross slip regime for the 1Cr13 stainless steel but little for Ti/C/Ti(C,N)/TiN multi-layer coatings. With the temperature increasing, the friction coefficient and the wear volume of the 1Cr13 alloy decreases and the wear volume of TiC/Ti(C, N)/TiN multi-layer coatings is invariant. TiC/Ti(C,N)/TiN multi-layer coatings have better wear-resistant capability than the 1Cr13 stainless steel, but the wear volume of the substrate increases greatly because of the grain-abrasion resulted from hard debris when TiC/Ti(C,N)/TiN multi-layer coatings are ground off. (authors)
International Nuclear Information System (INIS)
Photocatalytic decomposition of aqueous organic pollutant on semiconductor materials has been widely studied as a simple and clean process for organic pollutant removal. The reaction mechanism have been revealed and some fundamental requirements should be satisfied for high photocatalytic activity, such as high chemical, thermal stability in water, intense light absorption, efficient charge separation, large surface area, high pollutant adsorption ability, etc. However, until now on, no single material fulfills all these requirements. Therefore, lots of efforts have been made to enhance the activity of photocatalysts by several approaches. By controlling the band-gap of photocatalyst or combining with narrow band-gap semiconductor, the light absorption can expand to the visible-light spectrum region that increases the charge-carrier generation. By adopting nanostructured morphologies, large surface area can provide huge amount of surface reaction sites and reduce the charge-carrier recombination before it reaches these sites. Also, several reports have shown that, by increasing the adsorption of pollutant on the photocatalyst surface, synergistic enhancement can occur in the photocatalytic activity. Along with these fundamental requirements, photocatalysts should be non-toxic, abundant, and easily synthesizable for economical and eco-friendly applications. During a few decades, various inorganic semiconductors, especially, metal oxides (TiO2, ZnO2, WO3, etc), metal sulfides (CdS, PbS, etc), and dye molecules with a metal core (Ru-, Ir- based single-molecules) have been widely studied as a photocatalyst. However, even though lots of studies have been made, issues related to the potential threat against human health by using these kinds of metal-containing inorganic semiconductors are still under dispute. Recently, metal-free organic photocatalyst (g-C3N4, C3N3S3) have been synthesized, and showed outstanding photocatalytic activities for H2 production from water
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
Based on unit cell model,the 3D 4-directional braided composites can be simplified as unidirectional composites with different local axial coordinate system and the compliance matrix of unidirectional composites can be defined utilizing the bridge model.The total stiffness matrix of braided composites can be obtained by the volume average stiffness of unidirectional composites with different local axial coordinate system and the engineering elastic constants of braided composites were computed further.Based on the iso-strain assumption and the bridge model,the stress distribution of fiber bundle and matrix of different unidirectional composites can be determined and the tensile strength of 3D 4-directional braided composites was predicted by means of the Hoffman's failure criterion for the fiber bundle and Mises' failure criterion for the matrix.
Software for Computing, Archiving, and Querying Semisimple Braided Monoidal Category Data
Energy Technology Data Exchange (ETDEWEB)
2016-08-04
This software package collects various open source and freely available codes and algorithms to compute and archive the categorical data for certain semisimple braided monoidal categories. In particular, it computes the data for of group theoretical categories for academic research.
International Nuclear Information System (INIS)
In this study, the warpage simulation of a multi-layer printed circuit board (PCB) was performed as a function of various copper (Cu) patterns/photoimageable solder resist (PSR) composite patterns and their anisotropic viscoelastic properties. The thermo-mechanical properties of Cu/PSR patterns were obtained from finite element analysis (virtual test) and homogenized with anisotropic composite shell models that considered the viscoelastic properties. The multi-layer PCB model was simplified based on the unit Cu/PSR patterns and the warpage simulation during the reflow process was performed by using ABAQUS combined with a user-defined subroutine. From these results, it was demonstrated that the proposed anisotropic viscoelastic composite shell simulation technique can be successfully used to predict warpage of multi-layer PCBs during the reflow process. (paper)