Corrugated Membrane Nonlinear Deformation Process Calculation

OpenAIRE

A. S. Nikolaeva; S. A. Podkopaev

2015-01-01

Elastic elements are widely used in instrumentation. They are used to create a particular interference between the parts, for accumulating mechanical energy, as the motion transmission elements, elastic supports, and sensing elements of measuring devices. Device reliability and quality depend on the calculation accuracy of the elastic elements. A corrugated membrane is rather common embodiment of the elastic element.The corrugated membrane properties depend largely on its profile i.e. a gener...

Assessment of rail long-pitch corrugation

Science.gov (United States)

Valehrach, Jan; Guziur, Petr; Riha, Tomas; Plasek, Otto

2017-09-01

The paper focuses on defects of the running surface of the rail, namely the rail corrugation defect and specifically long-pitch corrugation in curves of small radii. These defects cause a shorter life of the rails, greater maintenance costs and increase the noise and vibration pollution. Therefore, it is very important to understand the formation and development of the imperfection of the rails. In the paper, various sections of railway tracks in the Czech Republic are listed, each of them completed with comparison of defect development, the particular track superstructure, rolling stock, axle load, traffic load etc. Based on performed measurements, defect development has been proved as different on sections with similar (or even same) parameters. The paper assumes that a train velocity is the significant circumstance for defect development rates. Assessment of track section with under sleeper pads, which are expected to be the one of the possible ways to suppress the corrugation defect development, is included in evaluation.

Theoretical prediction on corrugated sandwich panels under bending loads

Science.gov (United States)

Shu, Chengfu; Hou, Shujuan

2018-05-01

In this paper, an aluminum corrugated sandwich panel with triangular core under bending loads was investigated. Firstly, the equivalent material parameters of the triangular corrugated core layer, which could be considered as an orthotropic panel, were obtained by using Castigliano's theorem and equivalent homogeneous model. Secondly, contributions of the corrugated core layer and two face panels were both considered to compute the equivalent material parameters of the whole structure through the classical lamination theory, and these equivalent material parameters were compared with finite element analysis solutions. Then, based on the Mindlin orthotropic plate theory, this study obtain the closed-form solutions of the displacement for a corrugated sandwich panel under bending loads in specified boundary conditions, and parameters study and comparison by the finite element method were executed simultaneously.

CONTRIBUTIONS ON THE DESIGN OF UNCONVENTIONAL CORRUGATED BOARD STRUCTURES

Directory of Open Access Journals (Sweden)

NEIDONI Nadina

2015-06-01

Full Text Available The paper depicts a few contributions on the design of several unconventional corrugated board structures. In general, cardboard and corrugated cardboard is strongly linked to packaging. However, limiting these materials to their primary use does nothing else but to restrict the possibilities of using them in other interesting areas. Consequently, new structures built from cardboard have been imagined and in the paper there are presented a few unconventional uses of the corrugated fiberboard, namely as furniture elements, along with the technology used in the design and the manufacturing process.

Numerical and Experimental Investigations on Mechanical Behavior of Composite Corrugated Core

Science.gov (United States)

Dayyani, Iman; Ziaei-Rad, Saeed; Salehi, Hamid

2012-06-01

Tensile and flexural characteristics of corrugated laminate panels were studied using numerical and analytical methods and compared with experimental data. Prepreg laminates of glass fiber plain woven cloth were hand-laid by use of a heat gun to ease the creation of the panel. The corrugated panels were then manufactured by using a trapezoidal machined aluminium mould. First, a series of simple tension tests were performed on standard samples to evaluate the material characteristics. Next, the corrugated panels were subjected to tensile and three-point bending tests. The force-displacement graphs were recorded. Numerical and analytical solutions were proposed to simulate the mechanical behavior of the panels. In order to model the energy dissipation due to delamination phenomenon observed in tensile tests in all members of corrugated core, plastic behavior was assigned to the whole geometry, not only to the corner regions. Contrary to the literature, it is shown that the three-stage mechanical behavior of composite corrugated core is not confined to aramid reinforced corrugated laminates and can be observed in other types such as fiber glass. The results reveal that the mechanical behavior of the core in tension is sensitive to the variation of core height. In addition, for the first time, the behavior of composite corrugated core was studied and verified in bending. Finally, the analytical and numerical results were validated by comparing them with experimental data. A good degree of correlation was observed which showed the suitability of the finite element model for predicting the mechanical behavior of corrugated laminate panels.

Flow around a corrugated wing over the range of dragonfly flight

Science.gov (United States)

Padinjattayil, Sooraj; Agrawal, Amit

2017-11-01

The dragonfly flight is very much affected by the corrugations on their wings. A PIV based study is conducted on a rigid corrugated wing for a range of Reynolds number 300-12000 and three different angles of attack (5°-15°) to understand the mechanism of dragonfly flight better. The study revealed that the shape of the corrugation plays a key role in generating vortices. The vortices trapped in the valleys of corrugation dictates the shape of a virtual airfoil around the corrugated wing. A fluid roller bearing effect is created over the virtual airfoil when the trapped vortices merge with each other. A travelling wave produced by the moving virtual boundary around the fluid roller bearings avoids the formation of boundary layer on the virtual surface, thereby leading to high aerodynamic performance. It is found that the lift coefficient increases as the number of vortices increases on the suction surface. Also, it is shown that the partially merged co- rotating vortices give higher lift as compared to fully merged vortices. Further, the virtual airfoil formed around the corrugated wing is compared with a superhydrophobic airfoil which exhibits slip on its surface; several similarities in their flow characteristics are observed. The corrugated airfoil performs superior to the superhydrophobic airfoil in the aerodynamic efficiency due to the virtual slip caused by the travelling wave.

On the whistling of corrugated pipes with narrow cavities

NARCIS (Netherlands)

Golliard, J.; Belfroid, S.P.C.; González Diez, N.; Bendiksen, E.; Frimodt, C.

2013-01-01

Pipes with a corrugated inner surface, as used inflexible pipes for gas production and transport, can be subject to Flow-Induced Pulsations when the flow velocities are higher than a certain onset velocity. The onset velocity for classical corrugated pipes can be predicted on basis of the geometry

Fracture Behaviours in Compression-loaded Triangular Corrugated Core Sandwich Panels

Directory of Open Access Journals (Sweden)

Zaid N.Z.M.

2016-01-01

Full Text Available The failure modes occurring in sandwich panels based on the corrugations of aluminium alloy, carbon fibre-reinforced plastic (CFRP and glass fibre-reinforced plastic (GFRP are analysed in this work. The fracture behaviour of these sandwich panels under compressive stresses is determined through a series of uniform lateral compression performed on samples with different cell wall thicknesses. Compression test on the corrugated-core sandwich panels were conducted using an Instron series 4505 testing machine. The post-failure examinations of the corrugated-core in different cell wall thickness were conducted using optical microscope. Load-displacement graphs of aluminium alloy, GFRP and CFRP specimens were plotted to show progressive damage development with five unit cells. Four modes of failure were described in the results: buckling, hinges, delamination and debonding. Each of these failure modes may dominate under different cell wall thickness or loading condition, and they may act in combination. The results indicate that thicker composites corrugated-core panels tend can recover more stress and retain more stiffness. This analysis provides a valuable insight into the mechanical behaviour of corrugated-core sandwich panels for use in lightweight engineering applications.

Numerical investigation of the aerodynamic and structural characteristics of a corrugated wing

Science.gov (United States)

Hord, Kyle

Previous experimental studies on static, bio-inspired corrugated wings have shown that they produce favorable aerodynamic properties such as delayed stall compared to streamlined wings and flat plates at high Reynolds numbers (Re ≥ 4x104). The majority of studies have been carried out with scaled models of dragonfly forewings from the Aeshna Cyanea in either wind tunnels or water channels. In this thesis, the aerodynamics of a corrugated airfoil was studied using computational fluid dynamics methods at a low Reynolds number of 1000. Structural analysis was also performed using the commercial software SolidWorks 2009. The flow field is described by solving the incompressible Navier-Stokes equations on an overlapping grid using the pressure-Poisson method. The equations are discretized in space with second-order accurate central differences. Time integration is achieved through the second-order Crank-Nicolson implicit method. The complex vortex structures that form in the corrugated airfoil valleys and around the corrugated airfoil are studied in detail. Comparisons are made with experimental measurements from corrugated wings and also with simulations of a flat plate. Contrary to the studies at high Reynolds numbers, our study shows that at low Reynolds numbers the wing corrugation does not provide any aerodynamic benefit compared to a smoothed flat plate. Instead, the corrugated profile generates more pressure drag which is only partially offset by the reduction of friction drag, leading to more total drag than the flat plate. Structural analysis shows that the wing corrugation can increase the resistance to bending moments on the wing structure. A smoothed structure has to be three times thicker to provide the same stiffness. It was concluded the corrugated wing has the structural benefit to provide the same resistance to bending moments with a much reduced weight.

Design and manufacturing of skins based on composite corrugated laminates for morphing aerodynamic surfaces

Science.gov (United States)

Airoldi, Alessandro; Fournier, Stephane; Borlandelli, Elena; Bettini, Paolo; Sala, Giuseppe

2017-04-01

The paper discusses the approaches for the design and manufacturing of morphing skins based on rectangular-shaped composite corrugated laminates and proposes a novel solution to prevent detrimental effects of corrugation on aerodynamic performances. Additionally, more complex corrugated shapes are presented and analysed. The manufacturing issues related to the production of corrugated laminates are discussed and tests are performed to compare different solutions and to assess the validity of analytical and numerical predictions. The solution presented to develop an aerodynamically efficient skin consists in the integration of an elastomeric cover in the corrugated laminate. The related manufacturing process is presented and assessed, and a fully nonlinear numerical model is developed and characterized to study the behaviour of this skin concept in different load conditions. Finally, configurations based on combinations of individual rectangular-shaped corrugated panels are considered. Their structural properties are numerically investigated by varying geometrical parameters. Performance indices are defined to compare structural stiffness contributions in non-morphing directions with the ones of conventional panels of the same weight. Numerical studies also show that the extension of the concept to complex corrugated shapes may improve both the design flexibility and some specific performances with respect to rectangular shaped corrugations. The overall results validate the design approaches and manufacturing processes to produce corrugated laminates and indicate that the solution for the integration of an elastomeric cover is a feasible and promising method to enhance the aerodynamic efficiency of corrugated skins.

Mass transfer in corrugated-plate membrane modules. II. Ultrafiltration experiments

NARCIS (Netherlands)

van der Waal, M.J.; Stevanovic, S.; Racz, I.G.

1989-01-01

The application of corrugations as turbulence promoters in membrane filtration was studied. In ultrafiltration experiments with polysulfone membranes using Dextran T70 as solute, it was found that the corrugations result in reduced energy consumption or pressure drop compared with flat membranes at

Dynamic tension testing equipment for paperboard and corrugated fiberboard

Science.gov (United States)

W. D. Godshall

1965-01-01

The objective of this work was to develop a method, the testing equipment, and the instrumentation with which dynamic stress-strain information may be obtained for paperboards and built-up corrugated fiberboards as used in corrugated fiberboard containers. Much information is available on the properties of these materials when subjected to static or low rates of...

Atom chips in the real world: the effects of wire corrugation

Science.gov (United States)

Schumm, T.; Estève, J.; Figl, C.; Trebbia, J.-B.; Aussibal, C.; Nguyen, H.; Mailly, D.; Bouchoule, I.; Westbrook, C. I.; Aspect, A.

2005-02-01

We present a detailed model describing the effects of wire corrugation on the trapping potential experienced by a cloud of atoms above a current carrying micro wire. We calculate the distortion of the current distribution due to corrugation and then derive the corresponding roughness in the magnetic field above the wire. Scaling laws are derived for the roughness as a function of height above a ribbon shaped wire. We also present experimental data on micro wire traps using cold atoms which complement some previously published measurements [CITE] and which demonstrate that wire corrugation can satisfactorily explain our observations of atom cloud fragmentation above electroplated gold wires. Finally, we present measurements of the corrugation of new wires fabricated by electron beam lithography and evaporation of gold. These wires appear to be substantially smoother than electroplated wires.

Influence of presence of inclined centered baffle and corrugation frequency on natural convection heat transfer flow of air inside a square enclosure with corrugated side walls

Energy Technology Data Exchange (ETDEWEB)

Hussain, Salam Hadi; Jabbar, Mohammed Yousif; Mohamad, Ahmad Saddy [Mechanical Engineering Department, College of Engineering, Babylon University, Babylon Province (Iraq)

2011-09-15

The main objective of this study is to investigate the effect of presence of insulated inclined centered baffle and corrugation frequency on the steady natural convection in a sinusoidal corrugated enclosure. The present study is based on such a configuration where the two vertical sinusoidal walls are maintained at constant low temperature whereas a constant heat flux source whose length is 80% of the width of the enclosure is discretely embedded in the bottom wall. The remaining parts of the bottom wall and the top wall are adiabatic. The finite volume method has been used to solve the governing Navier-Stokes and the energy conservation equations of the fluid medium in the enclosure in order to investigate the effects of baffle inclination angles, corrugation frequencies and Grashof numbers on the fluid flow and heat transfer in the enclosure. The values of the governing parameters are the Grashof number Gr (10{sup 3}-10{sup 6}), the corrugation frequencies CF (1, 2 and 3), baffle inclination angles (0 deg. {<=} {phi} {<=} 150 deg.) and Prandtl number Pr (0.71). Results are presented in the form of streamline and isotherm plots. The results of this investigation are illustrated that the average Nusselt number increases with increase in both the Grashof number and corrugation frequency for different baffle inclination angles and the presence of inclined baffle and increasing the corrugation frequency have significant effects on the average Nusselt numbers, streamlines and isotherms inside the enclosure. The obtained numerical results have been compared with literature ones, and it gives a reliable agreement. (authors)

Role of Bénard-Marangoni instabilities during solvent evaporation in polymer surface corrugations.

Science.gov (United States)

Bassou, N; Rharbi, Y

2009-01-06

Film formation through the drying of polymer solutions is a widely used process in laboratories and in many industrial applications such as coatings. One of the main goals of these applications is to control the film surface morphology. In many cases, evaporation has been found to yield corrugated patterns on the free surface of films. This has been interpreted in terms of either mechanical or hydrodynamic instabilities. In this article, we present experimental results where mesoscale 2D well-ordered surface corrugation patterns are formed during solvent evaporation from polystyrene/toluene solutions. The transformation of Benard-Marangoni instabilities into surface corrugation is studied during the entire drying process using particle tracking, 3D morphology analyses, etc. We show that the corrugation wavelength is controlled by the Benard-Marangoni instability, whereas the corrugation amplitude is controlled by a mechanism that involves a high evaporation rate.

Stylus type MEMS texture sensor covered with corrugated diaphragm

Science.gov (United States)

Tsukamoto, Takashiro; Asao, Hideaki; Tanaka, Shuji

2017-09-01

In this paper, a stylus type MEMS texture sensor covered with a corrugated palylene diaphragm, which prevent debris from jamming into the sensor without significant degradation of sensitivity and bandwidth, was reported. A new fabrication process using a lost-foil method to make the corrugated diaphragm on a 3-axis piezoresistive force sensor at wafer level has been developed. The texture sensor could detect the surface microstructure as small as about 10 \

Fast rail corrugation detection based on texture filtering

Science.gov (United States)

Xiao, Jie; Lu, Kaixia

2018-02-01

The condition detection of rails in high-speed railway is one of the important means to ensure the safety of railway transportation. In order to replace the traditional manual inspection, save manpower and material resources, and improve the detection speed and accuracy, it is of great significance to develop a machine vision system for locating and identifying defects on rails automatically. Rail defects exhibit different properties and are divided into various categories related to the type and position of flaws on the rail. Several kinds of interrelated factors cause rail defects such as type of rail, construction conditions, and speed and/or frequency of trains using the rail. Rail corrugation is a particular kind of defects that produce an undulatory deformation on the rail heads. In high speed train, the corrugation induces harmful vibrations on wheels and its components and reduces the lifetime of rails. This type of defects should be detected to avoid rail fractures. In this paper, a novel method for fast rail corrugation detection based on texture filtering was proposed.

Bandwidth Study of the Microwave Reflectors with Rectangular Corrugations

Science.gov (United States)

Zhang, Liang; He, Wenlong; Donaldson, Craig R.; Cross, Adrian W.

2016-09-01

The mode-selective microwave reflector with periodic rectangular corrugations in the inner surface of a circular metallic waveguide is studied in this paper. The relations between the bandwidth and reflection coefficient for different numbers of corrugation sections were studied through a global optimization method. Two types of reflectors were investigated. One does not consider the phase response and the other does. Both types of broadband reflectors operating at W-band were machined and measured to verify the numerical simulations.

Numerical Investigation of the Fully-Developed Periodic Flow Field for Optimal Heat Transfer in Spirally Corrugated Tubes

DEFF Research Database (Denmark)

Hærvig, Jakob; Condra, Thomas Joseph; Sørensen, Kim

Even though the corrugated tube is a widely used technique to enhance transfer heat, the exact heat transfer enhancing mechanism remains relatively un-documented. Most studies attribute the favourable heat transfer characteristics to a swirling flow being present at higher corrugation....... In this study, a systematic approach relying on Computational Fluid Dynamics (CFD) is used to study and compare the heat transfer characteristics with the detailed flow field in the spirally corrugated tubes. By comparing the flow in 12 different spirally corrugated tubes at a fixed Reynolds number of 5000......, this study compares the flow field with the surface averaged Nusselt number to gain valuable insight into which flow phenomena causes favourable heat transfer characteristics. While the flow at low corrugations approximates the non-corrugated tube, higher corrugations of h/D creates a significant tangential...

A corrugated perfect magnetic conductor surface supporting spoof surface magnon polaritons.

Science.gov (United States)

Liu, Liang-liang; Li, Zhuo; Gu, Chang-qing; Ning, Ping-ping; Xu, Bing-zheng; Niu, Zhen-yi; Zhao, Yong-jiu

2014-05-05

In this paper, we demonstrate that spoof surface magnon polaritons (SSMPs) can propagate along a corrugated perfect magnetic conductor (PMC) surface. From duality theorem, the existence of surface electromagnetic modes on corrugated PMC surfaces are manifest to be transverse electric (TE) mode compared with the transverse magnetic (TM) mode of spoof surface plasmon plaritons (SSPPs) excited on corrugated perfect electric conductor surfaces. Theoretical deduction through modal expansion method and simulation results clearly verify that SSMPs share the same dispersion relationship with the SSPPs. It is worth noting that this metamaterial will have more similar properties and potential applications as the SSPPs in large number of areas.

Constructive fire protection of steel corrugated beams of buildings and other structures

Directory of Open Access Journals (Sweden)

Ilyin Nikolay

2017-01-01

Full Text Available The research introduces a methodology of establishing indicators of fire safety of a building in relation to a guaranteed duration of steel fire-proof corrugated beams resistance in conditions of standard fire tests. Indicators of fire safety are also established in the assessment of design limits of steel fire-proof corrugated beams during design process, construction or maintenance of the building as well as in reducing economic costs when testing steel structures for fire resisting property. The suggested methodology introduces the system of actions aimed to design constructive fire protection of steel corrugated beams of buildings. Technological effect is achieved by conducting firing tests of steel construction by non-destructive methods; the evaluation of fire resistance of fire-proof elements of corrugated beams (corrugated web, upper and lower shelves is identified by the least fire-proof element of a welded I-beam. In this methodology fire resistance duration of the constituent elements of a welded I-beam with account of its fire protection ability is described with an analytic function taken as variables. These variables are intensity strength of stresses and the degree of fire protection of a compound element.

Heat transfer enhancement and pumping power optimization using CuO-water nanofluid through rectangular corrugated pipe

Science.gov (United States)

Salehin, Musfequs; Ehsan, Mohammad Monjurul; Islam, A. K. M. Sadrul

2017-06-01

Heat transfer enhancement by corrugation in fluid domain is a popular method. The rate of improvement is more when it is used highly thermal conductive fluid as heating or cooling medium. In this present study, heat transfer augmentation was investigated numerically by implementing corrugation in the fluid domain and nanofluid as the base fluid in the turbulent forced convection regime. Finite volume method (FVM) was applied to solve the continuity, momentum and energy equations. All the numerical simulations were considered for single phase flow. A rectangle corrugated pipe with 5000 W/m2 constant heat flux subjected to the corrugated wall was considered as the fluid domain. In the range of Reynolds number 15000 to 40000, thermo-physical and hydrodynamic behavior was investigated by using CuO-water nanofluid from 1% to 5% volume fraction as the base fluid through the corrugated fluid domain. Corrugation justification was performed by changing the amplitude of the corrugation and the corrugation wave length for obtaining the increased heat transfer rate with minimum pumping power. For using CuO-water nanofluid, augmentation was also found more in the rectangle corrugated pipe both in heat transfer and pumping power requirement with the increase of Reynolds number and the volume fraction of nanofluid. For the increased pumping power, optimization of pumping power by using nanofluid was also performed for economic finding.

Waste paper recycling opportunities for government action. Vol. 4, corrugated waste. Final report

Energy Technology Data Exchange (ETDEWEB)

Bailey, J.; Love, P.

1978-01-01

This study analyzes current and expected corrugated waste market conditions in Canada, with the objective of identifying government initiatives which could permanently increase recovery levels. Short-term, practical measures are featured. National and regional demand, generation and recovery levels are examined, along with imports and exports to the USA. Over 70% of corrugated waste is consumed in Ontario and Quebec, and most of this waste is generated in those two provinces. Average recovery rates in most major urban areas are estimated at 30-40%. Future demand, generation, and recovery are estimated, and it is suggested that there will be enough domestic demand to permit reclamation of nearly 35% of Canada's total corrugated wastes. This potential level is not expected to change significantly, and new demand opportunities appear minimal. Examination of the potential for future imports from the USA indicates that availability will tighten over the medium term, necessitating a search for new corrugated waste supply sources. Possible sources include supermakets, retail chains and large assembly manufacturing establishments; one of the most promising of these sources is shopping malls, and a study is appended which examines the feasibility of a corrugated waste source separation program within a hypothetical mall. Possible government actions are outlined to improve reclamation and recycling of corrugated waste in Canada, including the improvement of local recovery capabilities in British Columbia, Ontario and Quebec, and the reduction of freight costs for moving corrugated waste from low-recovery areas to high-demand areas. 26 refs., 9 figs., 31 tabs.

Numerical analysis of beam with sinusoidally corrugated webs

Science.gov (United States)

Górecki, Marcin; Pieńko, Michał; Łagoda, GraŻyna

2018-01-01

The paper presents numerical tests results of the steel beam with sinusoidally corrugated web, which were performed in the Autodesk Algor Simulation Professional 2010. The analysis was preceded by laboratory tests including the beam's work under the influence of the four point bending as well as the study of material characteristics. Significant web's thickness and use of tools available in the software allowed to analyze the behavior of the plate girder as beam, and also to observe the occurrence of stresses in the characteristic element - the corrugated web. The stress distribution observed on the both web's surfaces was analyzed.

On the Fully-Developed Heat Transfer Enhancing Flow Field in Sinusoidally, Spirally Corrugated Tubes Using Computational Fluid Dynamics

DEFF Research Database (Denmark)

Hærvig, Jakob; Sørensen, Kim; Condra, Thomas Joseph

2017-01-01

A numerical study has been carried out to investigate heat transfer enhancing flow field in 28 geometrically different sinusoidally, spirally corrugated tubes. To vary the corrugation, the height of corrugation e/D and the length between two successive corrugated sections p/D are varied in the ra...

[Progressive damage monitoring of corrugated composite skins by the FBG spectral characteristics].

Science.gov (United States)

Zhang, Yong; Wang, Bang-Feng; Lu, Ji-Yun; Gu, Li-Li; Su, Yong-Gang

2014-03-01

In the present paper, a method of monitoring progressive damage of composite structures by non-uniform fiber Bragg grating (FBG) reflection spectrum is proposed. Due to the finite element analysis of corrugated composite skins specimens, the failure process under tensile load and corresponding critical failure loads of corrugated composite skin was predicated. Then, the non-uniform reflection spectrum of FBG sensor could be reconstructed and the corresponding relationship between layer failure order sequence of corrugated composite skin and FBG sensor reflection spectrums was acquired. A monitoring system based on FBG non-uniform reflection spectrum, which can be used to monitor progressive damage of corrugated composite skins, was built. The corrugated composite skins were stretched under this FBG non-uniform reflection spectrum monitoring system. The results indicate that real-time spectrums acquired by FBG non-uniform reflection spectrum monitoring system show the same trend with the reconstruction reflection spectrums. The maximum error between the corresponding failure and the predictive value is 8.6%, which proves the feasibility of using FBG sensor to monitor progressive damage of corrugated composite skin. In this method, the real-time changes in the FBG non-uniform reflection spectrum within the scope of failure were acquired through the way of monitoring and predicating, and at the same time, the progressive damage extent and layer failure sequence of corru- gated composite skin was estimated, and without destroying the structure of the specimen, the method is easy and simple to operate. The measurement and transmission section of the system are completely composed of optical fiber, which provides new ideas and experimental reference for the field of dynamic monitoring of smart skin.

Heat shrink formation of a corrugated thin film thermoelectric generator

International Nuclear Information System (INIS)

Sun, Tianlei; Peavey, Jennifer L.; David Shelby, M.; Ferguson, Scott; O’Connor, Brendan T.

2015-01-01

Highlights: • Demonstrate and characterize a thermoelectric generator with a corrugated geometry. • Employ a novel heat shrink fabrication approach compatible with low-cost processing. • Use thermal impedance modeling to explore design potential. • Corrugated design shown to be advantageous for low heat-flux density applications. - Abstract: A thin film thermoelectric (TE) generator with a corrugated architecture is demonstrated formed using a heat-shrink fabrication approach. Fabrication of the corrugated TE structure consists of depositing thin film thermoelectric elements onto a planar non-shrink polyimide substrate that is then sandwiched between two uniaxial stretch-oriented co-polyester (PET) films. The heat shrink PET films are adhered to the polyimide in select locations, such that when the structure is placed in a high temperature environment, the outer films shrink resulting in a corrugated core film and thermoelectric elements spanning between the outer PET films. The module has a cross-plane heat transfer architecture similar to a conventional bulk TE module, but with heat transfer in the plane of the thin film thermoelectric elements, which assists in maintaining a significant temperature difference across the thermoelectric junctions. In this demonstration, Ag and Ni films are used as the thermoelectric elements and a Seebeck coefficient of 14 μV K −1 is measured with a maximum power output of 0.22 nW per couple at a temperature difference of 7.0 K. We then theoretically consider the performance of this device architecture with high performance thermoelectric materials in the heat sink limited regime. The results show that the heat-shrink approach is a simple fabrication method that may be advantageous in large-area, low power density applications. The fabrication method is also compatible with simple geometric modification to achieve various form factors and power densities to customize the TE generator for a range of applications

Effect of varying geometrical parameters of trapezoidal corrugated-core sandwich structure

Directory of Open Access Journals (Sweden)

Zaid N.Z.M.

2017-01-01

Full Text Available Sandwich structure is an attractive alternative that increasingly used in the transportation and aerospace industry. Corrugated-core with trapezoidal shape allows enhancing the damage resistance to the sandwich structure, but on the other hand, it changes the structural response of the sandwich structure. The aim of this paper is to study the effect of varying geometrical parameters of trapezoidal corrugated-core sandwich structure under compression loading. The corrugated-core specimen was fabricated using press technique, following the shape of trapezoidal shape. Two different materials were used in the study, glass fibre reinforced plastic (GFRP and carbon fibre reinforced plastic (CFRP. The result shows that the mechanical properties of the core in compression loading are sensitive to the variation of a number of unit cells and the core thickness.

Theory of static friction: temperature and corrugation effects

International Nuclear Information System (INIS)

Franchini, A; Brigazzi, M; Santoro, G; Bortolani, V

2008-01-01

We present a study of the static friction, as a function of temperature, between two thick solid slabs. The upper one is formed of light particles and the substrate of heavy particles. We focus our attention on the interaction between the phonon fields of the two blocks and on the interface corrugation, among the various mechanisms responsible for the friction. To give evidence of the role played by the dynamical interaction of the substrate with the upper block, we consider both a substrate formed by fixed atoms and a substrate formed by mobile atoms. To study the effect of the corrugation, we model it by changing the range parameter σ in the Lennard-Jones interaction potential. We found that in the case of the mobile substrate there is a large momentum transfer from the substrate to the upper block. This momentum transfer increases on increasing the temperature and produces a large disorder in the upper block favouring a decrease of the static friction with respect to the case for a rigid substrate. Reducing the corrugation, we found that with a rigid substrate the upper block becomes nearly commensurate, producing an enhancement of the static friction with respect to that with a mobile substrate

Direct measurements of acoustic damping and sound amplification in corrugated pipes with flow

NARCIS (Netherlands)

Golliard, J.; Belfroid, S.P.C.; Vijlbrief, O.; Lunde, K.

2015-01-01

The flow-induced pulsations in corrugated pipes result from a feedback loop between an acoustic resonator and the noise amplification at each shear layer in the axisymmetric cavities forming the corrugations. The quality factor of the resonator is determined by the reflection coefficients at the

Axial Crushing Behaviors of Thin-Walled Corrugated and Circular Tubes - A Comparative Study

Science.gov (United States)

Reyaz-Ur-Rahim, Mohd.; Bharti, P. K.; Umer, Afaque

2017-10-01

With the help of finite element analysis, this research paper deals with the energy absorption and collapse behavior with different corrugated section geometries of hollow tubes made of aluminum alloy 6060-T4. Literature available experimental data were used to validate the numerical models of the structures investigated. Based on the results available for symmetric crushing of circular tubes, models were developed to investigate corrugated thin-walled structures behavior. To study the collapse mechanism and energy absorbing ability in axial compression, the simulation was carried in ABAQUS /EXPLICIT code. In the simulation part, specimens were prepared and axially crushed to one-fourth length of the tube and the energy diagram of crushing force versus axial displacement is shown. The effect of various parameters such as pitch, mean diameter, corrugation, amplitude, the thickness is demonstrated with the help of diagrams. The overall result shows that the corrugated section geometry could be a good alternative to the conventional tubes.

Numerical analysis of sandwich beam with corrugated core under three-point bending

Energy Technology Data Exchange (ETDEWEB)

Wittenbeck, Leszek [Poznan University of Technology, Institute of Mathematics Piotrowo Street No. 5, 60-965 Poznan (Poland); Grygorowicz, Magdalena; Paczos, Piotr [Poznan University of Technology, Institute of Applied Mechanics Jana Pawla IIStreet No. 24, 60-965 Poznan (Poland)

2015-03-10

The strength problem of sandwich beam with corrugated core under three-point bending is presented.The beam are made of steel and formed by three mutually orthogonal corrugated layers. The finite element analysis (FEA) of the sandwich beam is performed with the use of the FEM system - ABAQUS. The relationship between the applied load and deflection in three-point bending is considered.

Lamb wave band gaps in one-dimensional radial phononic crystal plates with periodic double-sided corrugations

Energy Technology Data Exchange (ETDEWEB)

Li, Yinggang [School of Mechanical Engineering and State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi’an Jiaotong University, Xi’an, 710049 (China); School of Transportation, Wuhan University of Technology, Wuhan 430070 (China); Chen, Tianning [School of Mechanical Engineering and State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi’an Jiaotong University, Xi’an, 710049 (China); Wang, Xiaopeng, E-mail: xpwang@mail.xjtu.edu.cn [School of Mechanical Engineering and State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi’an Jiaotong University, Xi’an, 710049 (China); Li, Suobin [School of Mechanical Engineering and State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi’an Jiaotong University, Xi’an, 710049 (China)

2015-11-01

In this paper, we present the theoretical investigation of Lamb wave propagation in one-dimensional radial phononic crystal (RPC) plates with periodic double-sided corrugations. The dispersion relations, the power transmission spectra, and the displacement fields of the eigenmodes are studied by using the finite element method based on two-dimensional axial symmetry models in cylindrical coordinates. Numerical results show that the proposed RPC plates with periodic double-sided corrugations can yield several band gaps with a variable bandwidth for Lamb waves. The formation mechanism of band gaps in the double-sided RPC plates is attributed to the coupling between the Lamb modes and the in-phase and out-phases resonant eigenmodes of the double-sided corrugations. We investigate the evolution of band gaps in the double-sided RPC plates with the corrugation heights on both sides arranged from an asymmetrical distribution to a symmetrical distribution gradually. Significantly, with the introduction of symmetric double-sided corrugations, the antisymmetric Lamb mode is suppressed by the in-phase resonant eigenmodes of the double-sided corrugations, resulting in the disappearance of the lowest band gap. Furthermore, the effects of the geometrical parameters on the band gaps are further explored numerically.

Evaluation of Steel Shear Walls Behavior with Sinusoidal and Trapezoidal Corrugated Plates

Directory of Open Access Journals (Sweden)

Emad Hosseinpour

2015-01-01

Full Text Available Reinforcement of structures aims to control the input energy of unnatural and natural forces. In the past four decades, steel shear walls are utilized in huge constructions in some seismic countries such as Japan, United States, and Canada to lessen the risk of destructive forces. The steel shear walls are divided into two types: unstiffened and stiffened. In the former, a series of plates (sinusoidal and trapezoidal corrugated with light thickness are used that have the postbuckling field property under overall buckling. In the latter, steel profile belt series are employed as stiffeners with different arrangement: horizontal, vertical, or diagonal in one side or both sides of wall. In the unstiffened walls, increasing the thickness causes an increase in the wall capacity under large forces in tall structures. In the stiffened walls, joining the stiffeners to the wall is costly and time consuming. The ANSYS software was used to analyze the different models of unstiffened one-story steel walls with sinusoidal and trapezoidal corrugated plates under lateral load. The obtained results demonstrated that, in the walls with the same dimensions, the trapezoidal corrugated plates showed higher ductility and ultimate bearing compared to the sinusoidal corrugated plates.

Plasma influence on the dispersion properties of finite-length, corrugated waveguides

OpenAIRE

Shkvarunets, A.; Kobayashi, S.; Weaver, J.; Carmel, Y.; Rodgers, J.; Antonsen, T.; Granatstein, V.L.; Destler, W.W.; Ogura, K.; Minami, K.

1996-01-01

We present an experimental study of the electromagnetic properties of transverse magnetic modes in a corrugated-wall cavity filled with a radially inhomogeneous plasma. The shifts of the .resonant frequencies of a finite-length, corrugated cavity were measured as a function of the background plasma density and the dispersion diagram was reconstructed up to a peak plasma density of 1012 em - 3. Good agreement with a calculated dispersion diagram is obtained for plasma densities below 5 X 1011 ...

Silicon Carbide Corrugated Mirrors for Space Telescopes, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Trex Enterprises Corporation (Trex) proposes technology development to manufacture monolithic, lightweight silicon carbide corrugated mirrors (SCCM) suitable for...

Pressure drop and stability of flow in Archimedean spiral tube with transverse corrugations

Directory of Open Access Journals (Sweden)

Đorđević Milan

2016-01-01

Full Text Available Isothermal pressure drop experiments were carried out for the steady Newtonian fluid flow in Archimedean spiral tube with transverse corrugations. Pressure drop correlations and stability criteria for distinguishing the flow regimes have been obtained in a continuous Reynolds number range from 150 to 15 000. The characterizing geometrical groups which take into account all the geometrical parameters of Archimedean spiral and corrugated pipe has been acquired. Before performing experiments over the Archimedean spiral, the corrugated straight pipe having high relative roughness e/d = 0.129 of approximately sinusoidal type was tested in order to obtain correlations for the Darcy friction factor. Insight into the magnitude of pressure loss in the proposed geometry of spiral solar receiver for different flow rates is important because of its effect upon the efficiency of the receiver. Although flow in spiral and corrugated geometries has the advantages of compactness and high heat transfer rates, the disadvantage of greater pressure drops makes hydrodynamic studies relevant. [Projekat Ministarstva nauke Republike Srbije, br. III 42006 i br. TR 33015

Design of Ultra-Wideband Tapered Slot Antenna by Using Binomial Transformer with Corrugation

Science.gov (United States)

Chareonsiri, Yosita; Thaiwirot, Wanwisa; Akkaraekthalin, Prayoot

2017-05-01

In this paper, the tapered slot antenna (TSA) with corrugation is proposed for UWB applications. The multi-section binomial transformer is used to design taper profile of the proposed TSA that does not involve using time consuming optimization. A step-by-step procedure for synthesis of the step impedance values related with step slot widths of taper profile is presented. The smooth taper can be achieved by fitting the smoothing curve to the entire step slot. The design of TSA based on this method yields results with a quite flat gain and wide impedance bandwidth covering UWB spectrum from 3.1 GHz to 10.6 GHz. To further improve the radiation characteristics, the corrugation is added on the both edges of the proposed TSA. The effects of different corrugation shapes on the improvement of antenna gain and front-to-back ratio (F-to-B ratio) are investigated. To demonstrate the validity of the design, the prototypes of TSA without and with corrugation are fabricated and measured. The results show good agreement between simulation and measurement.

Atom chips in the real world: the effects of wire corrugation

OpenAIRE

Schumm , Thorsten; Estève , Jérôme; Aussibal , Christine; Figl , Cristina; Trebbia , Jean-Baptiste; Nguyen , Hai; Mailly , Dominique; Bouchoule , Isabelle; Westbrook , Christoph I; Aspect , Alain

2005-01-01

International audience; We present a detailed model describing the effects of wire corrugation on the trapping potential experienced by a cloud of atoms above a current carrying micro wire. We calculate the distortion of the current distribution due to corrugation and then derive the corresponding roughness in the magnetic field above the wire. Scaling laws are derived for the roughness as a function of height above a ribbon shaped wire. We also present experimental data on micro wire traps u...

Plasma influence on the dispersion properties of finite-length, corrugated waveguides

Science.gov (United States)

Shkvarunets, A.; Kobayashi, S.; Weaver, J.; Carmel, Y.; Rodgers, J.; Antonsen, T. M., Jr.; Granatstein, V. L.; Destler, W. W.; Ogura, K.; Minami, K.

1996-03-01

We present an experimental study of the electromagnetic properties of transverse magnetic modes in a corrugated-wall cavity filled with a radially inhomogeneous plasma. The shifts of the resonant frequencies of a finite-length, corrugated cavity were measured as a function of the background plasma density and the dispersion diagram was reconstructed up to a peak plasma density of 1012 cm-3. Good agreement with a calculated dispersion diagram is obtained for plasma densities below 5×1011 cm-3.

Whistling of pipes with narrow corrugations: scale model tests and consequences for carcass design

NARCIS (Netherlands)

Golliard, J.; Belfroid, S.P.C.; Bendiksen, E.; Frimodt, C.

2013-01-01

Pipes for gas production and transport with a corrugated inner surface, as used in flexible pipes, can be subject to Flow-Induced Pulsations when the flow velocity is larger than a certain velocity. This onset velocity is dependent on the geometry of the corrugations, the operational conditions and

Corrugated thimble tube for controlling control rod descent in nuclear reactor

International Nuclear Information System (INIS)

Luetzow, H.J.

1981-01-01

A thimble tube construction is described which will provide a controlled descent for a control rod while minimizing the reaction forces which must be absorbed by the thimble tube and reducing the possibility that a foreign particle could interfere with the free descent of a control rod. A thimble tube is formed with helically-corrugate internal walls which cooperate with a control rod contained in the tube in an emergency situation to provide a progressively-increasing hydraulic restraining force as each adjacent corrugation is encountered

Optimum fiber distribution in singlewall corrugated fiberboard

Science.gov (United States)

Millard W. Johnson; Thomas J. Urbanik; William E. Denniston

1979-01-01

Determining optimum distribution of fiber through rational design of corrugated fiberboard could result in significant reductions in fiber required to meet end-use conditions, with subsequent reductions in price pressure and extension of the softwood timber supply. A theory of thin plates under large deformations is developed that is both kinematically and physically...

Effects of die profile on grain refinement in Al–Mg alloy processed by repetitive corrugation and straightening

Energy Technology Data Exchange (ETDEWEB)

Thangapandian, N., E-mail: erpandian@gmail.com [Department of Mechanical Engineering, College of Engineering Guindy, Anna University, Chennai 600025 (India); Balasivanandha Prabu, S. [Department of Mechanical Engineering, College of Engineering Guindy, Anna University, Chennai 600025 (India); Padmanabhan, K.A. [Centre for Nanotechnology, University of Hyderabad, Hyderabad 500046 (India)

2016-01-01

It is shown that a proper selection of corrugation die profile and die parameters is essential for achieving homogeneous grain refinement in materials subjected to repetitive corrugation and straightening (RCS). An Al–Mg (AA 5083) alloy was subjected to the RCS process using three different corrugation die profiles (V-groove, Flat groove, and Semi-circular groove), followed by straightening to determine the allowable maximum number of passes prior to surface cracking/fracture. Mechanical properties, i.e., hardness and tensile strength of the RCS samples were measured and compared as functions of corrugation die profiles and number of passes and the changes in microstructure. Grain refinement was studied using Electron Back Scattered Diffraction (EBSD) analysis and Transmission Electron Microscopy (TEM).

Efficiency enhancement of flexible OLEDs by using nano-corrugated substrates and conformal Ag transparent anodes

Directory of Open Access Journals (Sweden)

Li Wang

2018-05-01

Full Text Available In flexible OLEDs (FOLEDs, the traditional ITO anode has disadvantages such as refractive-index mismatches among substrate and other functional layers, leads to light loss of nearly 80%, meanwhile, its brittle nature and lack in raw materials hinder its further applications. We investigated an efficient FOLED using a semi-transparent silver (Ag anode, whereas the device was built on a nano-corrugated flexible polycarbonate (PC substrate prepared by thermal nanoimprint lithography. The corrugations were well preserved on each layer of the device, both the micro-cavity effect and surface plasmon polariton (SPP modes of light loss were effectively suppressed. As a result, the current efficiency of the FOLED using a conformal corrugated Ag anode enhanced by 100% compared with a planar Ag anode device, and enhanced by 13% with conventional ITO device. In addition, owing to the quasi-periodical arrangements of the corrugations, the device achieved broad spectra and Lambertian angular emission. The Ag anode significantly improved the bending properties of the OLED as compared to the conventional ITO device, leading to a longer lifetime in practical use. The proposed manufacturing strategy will be useful for fabricating nano corrugations on plastic substrate of FOLED in a cost-effective and convenient manner.

Efficiency enhancement of flexible OLEDs by using nano-corrugated substrates and conformal Ag transparent anodes

Science.gov (United States)

Wang, Li; Luo, Yu; Feng, Xueming; Pei, Yuechen; Lu, Bingheng; Cheng, Shenggui

2018-05-01

In flexible OLEDs (FOLEDs), the traditional ITO anode has disadvantages such as refractive-index mismatches among substrate and other functional layers, leads to light loss of nearly 80%, meanwhile, its brittle nature and lack in raw materials hinder its further applications. We investigated an efficient FOLED using a semi-transparent silver (Ag) anode, whereas the device was built on a nano-corrugated flexible polycarbonate (PC) substrate prepared by thermal nanoimprint lithography. The corrugations were well preserved on each layer of the device, both the micro-cavity effect and surface plasmon polariton (SPP) modes of light loss were effectively suppressed. As a result, the current efficiency of the FOLED using a conformal corrugated Ag anode enhanced by 100% compared with a planar Ag anode device, and enhanced by 13% with conventional ITO device. In addition, owing to the quasi-periodical arrangements of the corrugations, the device achieved broad spectra and Lambertian angular emission. The Ag anode significantly improved the bending properties of the OLED as compared to the conventional ITO device, leading to a longer lifetime in practical use. The proposed manufacturing strategy will be useful for fabricating nano corrugations on plastic substrate of FOLED in a cost-effective and convenient manner.

Flow Regimes of Air-Water Counterflow Through Cross Corrugated Parallel Plates

Energy Technology Data Exchange (ETDEWEB)

de Almeida, V.F.

2000-06-07

Heretofore unknown flow regimes of air-water counterflow through a pair of transparent vertical parallel cross corrugated plates were observed via high-speed video. Air flows upward driven by pressure gradient and water, downward driven by gravity. The crimp geometry of the corrugations was drawn from typical corrugated sheets used as filling material in modern structured packed towers. Four regimes were featured, namely, rivulet, bicontinuous, flooding fronts, and flooding waves. It is conceivable that the regimes observed might constitute the basis for understanding how gas and liquid phases contend for available space in the interstices of structured packings in packed towers. Flow regime transitions were expressed in terms of liquid load (liquid superficial velocity) and gas flow factor parameters commonly used in pressure drop and capacity curves. We have carefully examined the range of parameters equivalent to the ill-understood high-liquid-flow operation in packed towers. More importantly, our findings should prove valuable in validating improved first-principles modeling of gas-liquid flows in these industrially important devices.

Coupled-Mode Theory for Complex-Index, Corrugated Multilayer Stacks

DEFF Research Database (Denmark)

Lüder, Hannes; Gerken, Martina; Adam, Jost

, and by choosing a bi-orthogonal basis, obtained by solving the corresponding adjoint problem. With the once found modal solutions of the unperturbed waveguide, we can calculate the coupling coefficients, which describe the mode coupling caused by the introduced periodic corrugation. [1] C. Kluge et al., Opt......We present a coupled-mode theory (CMT) approach for modelling the modal behaviour of multi- layer thinfilm devices with complex material parameters and periodic corrugations. Our method provides fast computation and extended physical insight as compared to standard numerical methods...... to be non-Hermitian, introducing two major consequences. First, the eigenvalues (i. e. the mode neff) have to be found in the complex plane (Fig. 2). Second, the classical mode orthogonality is no longer valid. We address both challenges by a combination of three complex-root solving algorithms...

Application of the method of integral equations to calculating the electrodynamic characteristics of periodically corrugated waveguides

International Nuclear Information System (INIS)

Belov, V.E.; Rodygin, L.V.; Fil'chenko, S.E.; Yunakovskii, A.D.

1988-01-01

A method is described for calculating the electrodynamic characteristics of periodically corrugated waveguide systems. This method is based on representing the field as the solution of the Helmholtz vector equation in the form of a simple layer potential, transformed with the use of the Floquet conditions. Systems of compound integral equations based on a weighted vector function of the simple layer potential are derived for waveguides with azimuthally symmetric and helical corrugations. A numerical realization of the Fourier method is cited for seeking the dispersion relation of azimuthally symmetric waves of a circular corrugated waveguide

Graphene-assisted near-field radiative heat transfer between corrugated polar materials

International Nuclear Information System (INIS)

Liu, X. L.; Zhang, Z. M.

2014-01-01

Graphene has attracted great attention in nanoelectronics, optics, and energy harvesting. Here, the near-field radiative heat transfer between graphene-covered corrugated silica is investigated based on the exact scattering theory. It is found that graphene can improve the radiative heat flux between silica gratings by more than one order of magnitude and alleviate the performance sensitivity to lateral shift. The underlying mechanism is mainly attributed to the improved photon tunneling of modes away from phonon resonances. Besides, coating with graphene leads to nonlocal radiative transfer that breaks Derjaguin's proximity approximation and enables corrugated silica to outperform bulk silica in near-field radiation.

SELF-TRAPPING OF DISKOSEISMIC CORRUGATION MODES IN NEUTRON STAR SPACETIMES

Energy Technology Data Exchange (ETDEWEB)

Tsang, David [Center for Theory and Computation, Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Pappas, George [Department of Physics and Astronomy, The University of Mississippi, University, MS 38677 (United States)

2016-02-10

We examine the effects of higher-order multipole contributions of rotating neutron star (NS) spacetimes on the propagation of corrugation (c-)modes within a thin accretion disk. We find that the Lense–Thirring precession frequency, which determines the propagation region of the low-frequency fundamental corrugation modes, can experience a turnover allowing for c-modes to become self-trapped for sufficiently high dimensionless spin j and quadrupole rotational deformability α. If such self-trapping c-modes can be detected, e.g., through phase-resolved spectroscopy of the iron line for a high-spin low-mass accreting neutron star, this could potentially constrain the spin-induced NS quadrupole and the NS equation of state.

Self-Trapping of Diskoseismic Corrugation Modes in Neutron Star Spacetimes

Science.gov (United States)

Tsang, David; Pappas, George

2016-02-01

We examine the effects of higher-order multipole contributions of rotating neutron star (NS) spacetimes on the propagation of corrugation (c-)modes within a thin accretion disk. We find that the Lense-Thirring precession frequency, which determines the propagation region of the low-frequency fundamental corrugation modes, can experience a turnover allowing for c-modes to become self-trapped for sufficiently high dimensionless spin j and quadrupole rotational deformability α. If such self-trapping c-modes can be detected, e.g., through phase-resolved spectroscopy of the iron line for a high-spin low-mass accreting neutron star, this could potentially constrain the spin-induced NS quadrupole and the NS equation of state.

An Experimental Study on the Shear Hysteresis and Energy Dissipation of the Steel Frame with a Trapezoidal-Corrugated Steel Plate.

Science.gov (United States)

Shon, Sudeok; Yoo, Mina; Lee, Seungjae

2017-03-06

The steel frame reinforced with steel shear wall is a lateral load resisting system and has higher strength and shear performance than the concrete shear wall system. Especially, using corrugated steel plates in these shear wall systems improves out-of-plane stiffness and flexibility in the deformation along the corrugation. In this paper, a cyclic loading test of this steel frame reinforced with trapezoidal-corrugated steel plate was performed to evaluate the structural performance. The hysteresis behavior and the energy dissipation capacity of the steel frame were also compared according to the corrugated direction of the plate. For the test, one simple frame model without the wall and two frame models reinforced with the plate are considered and designed. The test results showed that the model reinforced with the corrugated steel plate had a greater accumulated energy dissipation capacity than the experimental result of the non-reinforced model. Furthermore, the energy dissipation curves of two reinforced frame models, which have different corrugated directions, produced similar results.

Flexural strengthening of Reinforced Concrete (RC) Beams Retrofitted with Corrugated Glass Fiber Reinforced Polymer (GFRP) Laminates

Science.gov (United States)

Aravind, N.; Samanta, Amiya K.; Roy, Dilip Kr. Singha; Thanikal, Joseph V.

2015-01-01

Strengthening the structural members of old buildings using advanced materials is a contemporary research in the field of repairs and rehabilitation. Many researchers used plain Glass Fiber Reinforced Polymer (GFRP) sheets for strengthening Reinforced Concrete (RC) beams. In this research work, rectangular corrugated GFRP laminates were used for strengthening RC beams to achieve higher flexural strength and load carrying capacity. Type and dimensions of corrugated profile were selected based on preliminary study using ANSYS software. A total of twenty one beams were tested to study the load carrying capacity of control specimens and beams strengthened with plain sheets and corrugated laminates using epoxy resin. This paper presents the experimental and theoretical study on flexural strengthening of Reinforced Concrete (RC) beams using corrugated GFRP laminates and the results are compared. Mathematical models were developed based on the experimental data and then the models were validated.

Research on a 170 GHz, 2 MW coaxial cavity gyrotron with inner-outer corrugation

Energy Technology Data Exchange (ETDEWEB)

Hou, Shenyong, E-mail: houshenyong@sohu.com [Yangtze Normal University, Chongqing, 408001 (China); Yu, Sheng; Li, Hongfu [University of Electronics Science and Technology of China, Chengdu 610054 (China)

2015-03-15

In this paper, a coaxial cavity gyrotron with inner-outer corrugation is researched. The electron kineto-equations and the first order transmission line equations of the gyrotron are derived from Lorentz force equation and the transmission line theory, respectively. And then, a 2 MW, 170 GHz coaxial cavity gyrotron with inner-outer corrugation is designed. By means of numerical calculation, the beam-wave interaction of the coaxial cavity gyrotron with inner-outer corrugation is investigated. Results show that the efficient and the outpower of the gyrotron are 42.3% and 2.38 MW, respectively.

Beam Expansion of Blind Spot Detection Radar Antennas Using a Radome with Defected Corrugated Inner Wall

Directory of Open Access Journals (Sweden)

Hayeon Kim

2017-01-01

Full Text Available A beam expanding radome for 76.5 GHz automotive radar antennas is presented whose inner surface is engraved with corrugations. The radar used for blind spot detection (BSD requires a very wide beam width to ensure longer time for tracking out-of-sight objects. It is found that the corrugations modulate the phase velocities of the waves along the surface, which increases beam width in the far field. In addition, defects in the corrugation increase beam width even further. The presented structure satisfies the beam width requirement while keeping a low profile.

Squeezed-light generation in a nonlinear planar waveguide with a periodic corrugation

International Nuclear Information System (INIS)

Perina, Jan Jr.; Haderka, Ondrej; Sibilia, Concita; Bertolotti, Mario; Scalora, Michael

2007-01-01

Two-mode nonlinear interaction (second-harmonic and second-subharmonic generation) in a planar waveguide with a small periodic corrugation at the surface is studied. Scattering of the interacting fields on the corrugation leads to constructive interference that enhances the nonlinear process provided that all the interactions are phase matched. Conditions for the overall phase matching are found. Compared with a perfectly quasi-phase-matched waveguide, better values of squeezing as well as higher intensities are reached under these conditions. Procedure for finding optimum values of parameters for squeezed-light generation is described

Enhanced heat transfer with corrugated flow channel in anode side of direct methanol fuel cells

International Nuclear Information System (INIS)

Heidary, H.; Abbassi, A.; Kermani, M.J.

2013-01-01

Highlights: • Effect of corrugated flow channel on the heat exchange of DMFC is studied. • Corrugated boundary (except rectangular type) increase heat transfer up to 90%. • Average heat transfer in rectangular-corrugated boundary is less than straight one. • In Re > 60, wavy shape boundary has highest heat transfer. • In Re < 60, triangular shape boundary has highest heat transfer. - Abstract: In this paper, heat transfer and flow field analysis in anode side of direct methanol fuel cells (DMFCs) is numerically studied. To enhance the heat exchange between bottom cold wall and core flow, bottom wall of fluid delivery channel is considered as corrugated boundary instead of straight (flat) one. Four different shapes of corrugated boundary are recommended here: rectangular shape, trapezoidal shape, triangular shape and wavy (sinusoidal) shape. The top wall of the channel (catalyst layer boundary) is taken as hot boundary, because reaction occurs in catalyst layer and the bottom wall of the channel is considered as cold boundary due to coolant existence. The governing equations are numerically solved in the domain by the control volume approach based on the SIMPLE technique (1972). A wide spectrum of numerical studies is performed over a range of various shape boundaries, Reynolds number, triangle block number, and the triangle block amplitude. The performed parametric studies show that corrugated channel with trapezoidal, triangular and wavy shape enhances the heat exchange up to 90%. With these boundaries, cooling purpose of reacting flow in anode side of DMFCs would be better than straight one. Also, from the analogy between the heat and mass transfer problems, it is expected that the consumption of reacting species within the catalyst layer of DMFCs enhance. The present work provides helpful guidelines to the bipolar plate manufacturers of DMFCs to considerably enhance heat transfer and performance of the anode side of DMFC

Exergy Based Performance Analysis of Double Flow Solar Air Heater with Corrugated Absorber

OpenAIRE

S. P. Sharma; Som Nath Saha

2017-01-01

This paper presents the performance, based on exergy analysis of double flow solar air heaters with corrugated and flat plate absorber. A mathematical model of double flow solar air heater based on energy balance equations has been presented and the results obtained have been compared with that of a conventional flat-plate solar air heater. The double flow corrugated absorber solar air heater performs thermally better than the flat plate double flow and conventional flat-plate solar air heate...

Hydraulic and thermal behaviour of a corrugated plane canal. Application to plate-based heat exchangers

International Nuclear Information System (INIS)

Amblard, Alain

1986-01-01

As corrugations are often used in heat exchangers in order to promote heat exchange mechanisms through a reduction of boundary layer thickness, an increase of turbulence within the boundary layer, and an increase of exchange surface, the objectives of this research thesis are, on the one hand, to determine the influence of corrugation geometry on heat exchange and friction laws, and, on the other hand, to develop a computing software to describe the flow and heat exchange in the elementary canal. This study is limited to the case of single-phase forced convection in water. After a bibliographical overview on the hydraulic and thermal behaviour of corrugated surfaces used in heat exchangers, the author presents the different studied geometries, and the experimental installation used to determine the friction and exchange coefficient in a vertical duct formed by two corrugated plates. Experimental results are presented and compared with respect to the shape of exchange surfaces. The author then reports the use of two-dimensional code used to describe the flow in an exchanger duct [fr

Numerical Investigation of Corrugated Wire Mesh Laminate

Directory of Open Access Journals (Sweden)

Jeongho Choi

2013-01-01

Full Text Available The aim of this work is to develop a numerical model of Corrugated Wire Mesh Laminate (CWML capturing all its complexities such as nonlinear material properties, nonlinear geometry and large deformation behaviour, and frictional behaviour. Development of such a model will facilitate numerical simulation of the mechanical behaviour of the wire mesh structure under various types of loading as well as the variation of the CWML configuration parameters to tailor its mechanical properties to suit the intended application. Starting with a single strand truss model consisting of four waves with a bilinear stress-strain model to represent the plastic behaviour of stainless steel, the finite element model is gradually built up to study single-layer structures with 18 strands of corrugated wire meshes consistency and double- and quadruple-layered laminates with alternating crossply orientations. The compressive behaviour of the CWML model is simulated using contact elements to model friction and is compared to the load-deflection behaviour determined experimentally in uniaxial compression tests. The numerical model of the CWML is then employed to conduct the aim of establishing the upper and lower bounds of stiffness and load capacity achievable by such structures.

Multi-objective shape optimization of double pipe heat exchanger with inner corrugated tube using RSM method

International Nuclear Information System (INIS)

Han, Huai-Zhi; Li, Bing-Xi; Wu, Hao; Shao, Wei

2015-01-01

Integrated a fully developing three-dimensional heat transfer and flow model, a multi-objective optimization aims to fulfill the geometric design for double-tube heat exchangers with inner corrugated tube is investigated in this work with RSM. Dimensionless corrugation pitch (p/D), dimensionless corrugation height (H/D), dimensionless corrugation radius (r/D) and Reynolds number (Re) are considered as four design parameters. Considering the process parameters, the characteristic numbers involving heat transfer characteristic, resistance characteristic and overall heat transfer performance calculated by CFD, and are served as objective functions to the RSM (Nu c , f c , Nu c /Nu s , f c /f s and h in this paper). The results of optimal designs are a set of multiple optimum solutions, called 'Pareto optimal solutions'. It reveals the identical tendency of Nu c /Nu s and f c /f s reflecting the conflict between them that means augmenting the heat transfer performance with various design parameters in the optimal situation inevitably sacrificed the increase of flow resistance. According to the Pareto optimal curves, the optimum designing parameters of double pipe heat exchanger with inner corrugated tube under the constrains of Nu c /Nu s ≥1.2 are found to be P/D = 0.82, H/D = 0.22, r/D = 0.23, Re = 26,263, corresponding to the maximum value of η = 1.12. (authors)

Determination of transfer parameters in corrugated plates exchangers

International Nuclear Information System (INIS)

Silva Lima Filho, S. da.

1984-01-01

In this work is presented a experimental study about the forced convenction problem in vee-corrugated exchangers, with flow in the transversal sense, and parallel plates exchangers in which the isotermal plate is equivalent to the absobing one and the other plate is adiabatic. Global values of the transfer coefficients were experimentally obtained by application of the Naphthalene Sublimation Technique in accordance with the analogy between heat and mass transfer. The results were expressed in terms of Sh sup(-) /Sc sup(0,4) that according to the analogy is equal the Nu sup(-) / Pr sup(0,4) in function of the Reynolds number. The ratio between the lenght of the channel and the average spacing between plates L/2a was ranged in all the exchangers. Parameters of transfer to angles of 45 0 and 31 0 were determined in the corrugated plates exchangers. The experimental results obtained were analyzed and compared among them. Finally practical applications of these results are presented to heat exchangers with similars geometric characteristics. (Author) [pt

Modeling and experimental study of a corrugated wick type solar still: Comparative study with a simple basin type

International Nuclear Information System (INIS)

Matrawy, K.K.; Alosaimy, A.S.; Mahrous, A.-F.

2015-01-01

Highlights: • Performance of corrugated wick type solar still is compared with simple type. • Corrugated porous surface contributes by about 75% of the total productivity. • Productivity of corrugated solar still was 34% more than that for simple type. - Abstract: In the present work, the productivity of a solar still is modified by forming the evaporative surface as a corrugated shape as well as by decreasing the heat capacity with the use of a porous material. This target has been achieved by using black clothes in a corrugated shape that are immersed in water where the clothes absorbs water and get saturated by capillary effect. Along with the proposed corrugated wick type solar still, a simple basin still type was fabricated and tested to compare the enhancement accomplished by the developed solar still. Inclined reflectors were used to augment the solar radiation incident on the plane of the developed solar stills. The energy balance in the developed mathematical models takes into consideration the glass covers, the porous material, along with the portion of water exposed to the transmitted solar radiation as well as the portion of water shaded by the corrugated surface. The developed mathematical model was validated by fabricating and testing two models for the proposed and simple basin solar stills under the same conditions. Good agreement between the simulated and experimental results has been detected. It has been found that an improvement of about 34% in the productivity for the proposed wick type solar still is gained as compared to the simple basin case. Also, the best tilt angle for the inclined reflector has been found to be about 30° with respect to the vertical direction of the setup under consideration.

Comparison of heat transfer in straight and corrugated minichannels with two-phase flow

Directory of Open Access Journals (Sweden)

Peukert P.

2014-03-01

Full Text Available Measurements of heat transfer rates performed with an experimental condensation heat exchanger are reported for a corrugated minichannel tube and for a straight minichannel tube. The two cases were compared at same flow regimes. The corrugation appears advantageous for relatively low steam pressures and flow rates where much higher heat transfer rates were observed close to the steam entrance, thus allowing shortening the heat exchanger with the associated advantages of costs lowering and smaller built-up space. At high steam pressures and high flow rates both tubes performed similarly.

Experimental study on the heat transfer characteristics in corrugated and flat plate type heat exchanger

Energy Technology Data Exchange (ETDEWEB)

Park, Jung Hun; Jeong, Yong Ki; Jeon, Chung Hwan; Chang, Young June [Busan National Univ., Busan (Korea, Republic of); Lim, Hyeok [DHT, Busan (Korea, Republic of)

2003-07-01

An experiment was performed to study heat transfer characteristics between corrugated heat exchanger and flat plate type one. While heat capacity(13.86kW) was provided constantly and the flow speed was varied from 2.8 to 17.9m/s, the temperature and the pressure drop were measured. Furthermore, heat transfer coefficient, Colburn factor and Nusselt number were calculated using them. With increase of the flow speed for both exchangers, the coefficient and the pressure drop increased, but Colburn factor decreased. The coefficient, pressure drop and Colburn factor of the corrugated type were all higher than those of the flat one, which is due to the flow interruption with recirculation and reattachment of the corrugated type. The empirical correlations of Nusselt number were suggested for the tested two heat exchangers.

Corrugation Architecture Enabled Ultraflexible Wafer-Scale High-Efficiency Monocrystalline Silicon Solar Cell

KAUST Repository

Bahabry, Rabab R.

2018-01-02

Advanced classes of modern application require new generation of versatile solar cells showcasing extreme mechanical resilience, large-scale, low cost, and excellent power conversion efficiency. Conventional crystalline silicon-based solar cells offer one of the most highly efficient power sources, but a key challenge remains to attain mechanical resilience while preserving electrical performance. A complementary metal oxide semiconductor-based integration strategy where corrugation architecture enables ultraflexible and low-cost solar cell modules from bulk monocrystalline large-scale (127 × 127 cm) silicon solar wafers with a 17% power conversion efficiency. This periodic corrugated array benefits from an interchangeable solar cell segmentation scheme which preserves the active silicon thickness of 240 μm and achieves flexibility via interdigitated back contacts. These cells can reversibly withstand high mechanical stress and can be deformed to zigzag and bifacial modules. These corrugation silicon-based solar cells offer ultraflexibility with high stability over 1000 bending cycles including convex and concave bending to broaden the application spectrum. Finally, the smallest bending radius of curvature lower than 140 μm of the back contacts is shown that carries the solar cells segments.

Corrugation Architecture Enabled Ultraflexible Wafer-Scale High-Efficiency Monocrystalline Silicon Solar Cell

KAUST Repository

Bahabry, Rabab R.; Kutbee, Arwa T.; Khan, Sherjeel M.; Sepulveda, Adrian C.; Wicaksono, Irmandy; Nour, Maha A.; Wehbe, Nimer; Almislem, Amani Saleh Saad; Ghoneim, Mohamed T.; Sevilla, Galo T.; Syed, Ahad; Shaikh, Sohail F.; Hussain, Muhammad Mustafa

2018-01-01

Advanced classes of modern application require new generation of versatile solar cells showcasing extreme mechanical resilience, large-scale, low cost, and excellent power conversion efficiency. Conventional crystalline silicon-based solar cells offer one of the most highly efficient power sources, but a key challenge remains to attain mechanical resilience while preserving electrical performance. A complementary metal oxide semiconductor-based integration strategy where corrugation architecture enables ultraflexible and low-cost solar cell modules from bulk monocrystalline large-scale (127 × 127 cm) silicon solar wafers with a 17% power conversion efficiency. This periodic corrugated array benefits from an interchangeable solar cell segmentation scheme which preserves the active silicon thickness of 240 μm and achieves flexibility via interdigitated back contacts. These cells can reversibly withstand high mechanical stress and can be deformed to zigzag and bifacial modules. These corrugation silicon-based solar cells offer ultraflexibility with high stability over 1000 bending cycles including convex and concave bending to broaden the application spectrum. Finally, the smallest bending radius of curvature lower than 140 μm of the back contacts is shown that carries the solar cells segments.

Impact of substrate corrugation on the sliding friction levels of adsorbed films.

Science.gov (United States)

Coffey, T; Krim, J

2005-08-12

We report a quartz crystal microbalance (QCM) study of sliding friction for solid xenon monolayers at 77 K on Cu(111), Ni(111), graphene/Ni(111), and C(60) substrates. Simulations have predicted a strong dependence of phononic friction coefficient (eta) on surface corrugation in systems with similar lattice spacing, eta approximately U(2)(0), but this has never before been shown experimentally. In order to make direct comparisons with theory, substrates with similar lattice spacing but varying amplitudes of surface corrugation were studied. QCM data reveal friction levels proportional to U(2)(0), validating current theoretical and numerical predictions. Measurements of Xe/C(60) are also included for comparison purposes.

Evaluation of Thermo-Fluid Performance of Compact Heat Exchanger with Corrugated Wall Channels

International Nuclear Information System (INIS)

Tak, Nam Il; Lee, Won Jae

2006-01-01

One of the key components of an indirect nuclear hydrogen production system is an intermediate heat exchanger (IHX). For the IHX, a printed circuit heat exchanger (PCHE) is known as one of the promising types due to its compactness and ability to operate at high temperatures and under high pressures. The PCHE is a relatively new heat exchanger. It has been commercially manufactured only since 1985 and solely by one British vendor, HeatricTM. Due to its short history and limited production, sufficient information about the PCHE is not available for the design of the IHX in open literatures. The predominant shape of flow channels of the PCHE is laterally corrugated. The flow in a corrugated wall channel is very interesting since a variety of flow phenomena can be considered by changing the amplitude-to-wavelength ratio. In the present paper, thermo-fluid performance of a heat exchanger with a typical PCHE geometry has been evaluated. Computational fluid dynamics (CFD) analysis was performed to analyze a gas flow behavior in a corrugated wall channel

Compact Elliptically Tapered Slot Antenna with Non-uniform Corrugations for Ultra-wideband Applications

Directory of Open Access Journals (Sweden)

F. G. Zhu

2013-04-01

Full Text Available A small size elliptically tapered slot antenna (ETSA fed by coplanar waveguide (CPW for ultra-wideband (UWB applications is proposed. It is printed on an FR4 substrate and occupies a size of 37×34×0.8 mm^3. A pair of quarter circular shapes is etched on the radiator to reduce the size. To overcome the limitation of uniform corrugation, non-uniform corrugation is utilized to reduce the cross-polarization level. A parametric study is carried out to investigate the effects of circular cut and corrugations. In order to validate the design, a prototype is fabricated and measured. Both simulated and measured results confirm that the proposed antenna achieves a good performance of a reflection coefficient below -10 dB from 3.1 GHz to 10.6 GHz, including a maximum antenna gain of 8.1dBi, directional patterns in the end-fire direction, low cross-polarization level below -20 dB and linear phase response. The antenna is promising for applications in UWB impulse radar imaging.

A magnetically tunable non-Bragg defect mode in a corrugated waveguide filled with liquid crystals

Science.gov (United States)

Zhang, Lu; Fan, Ya-Xian; Liu, Huan; Han, Xu; Lu, Wen-Qiang; Tao, Zhi-Yong

2018-04-01

A magnetically tunable, non-Bragg defect mode (NBDM) was created in the terahertz frequency range by inserting a defect in the middle of a periodically corrugated waveguide filled with liquid crystals (LCs). In the periodic waveguide, non-Bragg gaps beyond the Bragg ones, which appear in the transmission spectra, are created by different transverse mode resonances. The transmission spectra of the waveguide containing a defect showed that a defect mode was present inside the non-Bragg gap. The NBDM has quite different features compared to the Bragg defect mode, which includes more complex, high-order guided wave modes. In our study, we filled the corrugated waveguide with LCs to realize the tunability of the NBDM. The simulated results showed that the NBDM in a corrugated waveguide filled with LCs can be used in filters, sensors, switches, and other terahertz integrated devices.

Variable stiffness corrugated composite structure with shape memory polymer for morphing skin applications

Science.gov (United States)

Gong, Xiaobo; Liu, Liwu; Scarpa, Fabrizio; Leng, Jinsong; Liu, Yanju

2017-03-01

This work presents a variable stiffness corrugated structure based on a shape memory polymer (SMP) composite with corrugated laminates as reinforcement that shows smooth aerodynamic surface, extreme mechanical anisotropy and variable stiffness for potential morphing skin applications. The smart composite corrugated structure shows a low in-plane stiffness to minimize the actuation energy, but also possess high out-of-plane stiffness to transfer the aerodynamic pressure load. The skin provides an external smooth aerodynamic surface because of the one-sided filling with the SMP. Due to variable stiffness of the shape memory polymer the morphing skin exhibits a variable stiffness with a change of temperature, which can help the skin adjust its stiffness according different service environments and also lock the temporary shape without external force. Analytical models related to the transverse and bending stiffness are derived and validated using finite element techniques. The stiffness of the morphing skin is further investigated by performing a parametric analysis against the geometry of the corrugation and various sets of SMP fillers. The theoretical and numerical models show a good agreement and demonstrate the potential of this morphing skin concept for morphing aircraft applications. We also perform a feasibility study of the use of this morphing skin in a variable camber morphing wing baseline. The results show that the morphing skin concept exhibits sufficient bending stiffness to withstand the aerodynamic load at low speed (less than 0.3 Ma), while demonstrating a large transverse stiffness variation (up to 191 times) that helps to create a maximum mechanical efficiency of the structure under varying external conditions.

Self-standing corrugated Ag and Au-nanorods for plasmonic applications

DEFF Research Database (Denmark)

Habouti, S.; Mátéfi-Tempfli, M.; Solterbeck, C.-H.

2011-01-01

We use home-made Si-supported anodized alumina thin film templates for the electrodeposition of large area self-standing Ag- and Au-nanorod (Au-NR) arrays. The deposition conditions chosen, i.e. electrolyte composition and deposition voltage, lead to a corrugated rod morphology, particularly for Au...

Numerical study on the flow and heat transfer characteristics of slush nitrogen in a corrugated pipe

Science.gov (United States)

Li, Y. J.; Wu, S. Q.; Jin, T.

2017-12-01

Slush nitrogen has lower temperature, higher density and higher heat capacity than that of liquid nitrogen at normal boiling point. It is considered to be a potential coolant for high-temperature superconductive cables (HTS) that would decrease nitrogen consumption and storage cost. The corrugated pipe can help with the enhancement of heat transfer and flexibility of the coolants for HTS cables. In this paper, a 3-D Euler-Euler two-fluid model has been developed to study the flow and heat transfer characteristics of slush nitrogen in a horizontal helically corrugated pipe. By comparing with the empirical formula for pressure drop, the numerical model is confirmed to be effective for the prediction of slush nitrogen flow in corrugated pipes. The flow and heat transfer characteristics of slush nitrogen in a horizontal pipe at various working conditions (inlet solid fraction of 0-20%, inlet velocity of 0-3 m/s, heat flux of 0-12 kW/m2) have been analyzed. The friction factor of slush nitrogen is lower than that of subcooled liquid nitrogen when the slush Reynolds number is higher than 4.2×104. Moreover, the heat transfer coefficient of slush nitrogen flow in the corrugated pipe is higher than that of subcooled liquid nitrogen at velocities which is higher than that 1.76 m/s, 0.91 m/s and 0.55 m/s for slush nitrogen with solid fraction of 5%, 10% and 20%, respectively. The slush nitrogen has been confirmed to have better heat transfer performance and lower pressure drop instead of using liquid nitrogen flowing through a helically corrugated pipe.

Improvement of formability for fabricating thin continuously corrugated structures in sheet metal forming process

International Nuclear Information System (INIS)

Choi, Sung Woo; Park, Sang Hu; Park, Seong Hun; Ha, Man Yeong; Jeong, Ho Seung; Cho, Jong Rae

2012-01-01

A stamping process is widely used for fabricating various sheet metal parts for vehicles, airplanes, and electronic devices by the merit of low processing cost and high productivity. Recently, the use of thin sheets with a corrugated structure for sheet metal parts has rapidly increased for use in energy management devices, such as heat exchangers, separators in fuel cells, and many others. However, it is not easy to make thin corrugated structures directly using a single step stamping process due to their geometrical complexity and very thin thickness. To solve this problem, a multi step stamping (MSS) process that includes a heat treatment process to improve formability is proposed in this work: the sequential process is the initial stamping, heat treatment, and final shaping. By the proposed method, we achieved successful results in fabricating thin corrugated structures with an average thickness of 75μm and increased formability of about 31% compared to the single step stamping process. Such structures can be used in a plate-type heat exchanger requiring low weight and a compact shape

Aeroacoustics of the swinging corrugated tube : voice of the dragon

NARCIS (Netherlands)

Nakiboglu, G.; Rudenko, O.; Hirschberg, A.

2012-01-01

When one swings a short corrugated pipe segment around one’s head, it produces a musically interesting whistling sound. As a musical toy it is called a "Hummer" and as a musical instrument, the "Voice of the Dragon." The fluid dynamics aspects of the instrument are addressed, corresponding to the

Measuring the height-to-height correlation function of corrugation in suspended graphene

International Nuclear Information System (INIS)

Kirilenko, D.A.; Brunkov, P.N.

2016-01-01

Nanocorrugation of 2D crystals is an important phenomenon since it affects their electronic and mechanical properties. The corrugation may have various sources; one of them is flexural phonons that, in particular, are responsible for the thermal conductivity of graphene. A study of corrugation of just the suspended graphene can reveal much of valuable information on the physics of this complicated phenomenon. At the same time, the suspended crystal nanorelief can hardly be measured directly because of high flexibility of the 2D crystal. Moreover, the relief portion related to rapid out-of-plane oscillations (flexural phonons) is also inaccessible by such measurements. Here we present a technique for measuring the Fourier components of the height–height correlation function H(q) of suspended graphene which includes the effect of flexural phonons. The technique is based on the analysis of electron diffraction patterns. The H(q) is measured in the range of wavevectors q≈0.4–4.5 nm"−"1. At the upper limit of this range H(q) does follow the T/κq"4 law. So, we measured the value of suspended graphene bending rigidity κ=1.2±0.4 eV at ambient temperature T≈300 K. At intermediate wave vectors, H(q) follows a slightly weaker exponent than theoretically predicted q"−"3"."1"5 but is closer to the results of the molecular dynamics simulation. At low wave vectors, the dependence becomes even weaker, which may be a sign of influence of charge carriers on the dynamics of undulations longer than 10 nm. The technique presented can be used for studying physics of flexural phonons in other 2D materials. - Highlights: • A technique for measuring free-standing 2D crystal corrugation is proposed. • The height-to-height correlation function of the suspended graphene corrugation is measured. • Various parameters of the intrinsic graphene properties are experimentally determined.

Two-phase flow patterns in adiabatic and diabatic corrugated plate gaps

Science.gov (United States)

Polzin, A.-E.; Kabelac, S.; de Vries, B.

2016-09-01

Correlations for two-phase heat transfer and pressure drop can be improved considerably, when they are adapted to specific flow patterns. As plate heat exchangers find increasing application as evaporators and condensers, there is a need for flow pattern maps for corrugated plate gaps. This contribution presents experimental results on flow pattern investigations for such a plate heat exchanger background, using an adiabatic visualisation setup as well as a diabatic setup. Three characteristic flow patterns were observed in the considered range of two-phase flow: bubbly flow, film flow and slug flow. The occurrence of these flow patterns is a function of mass flux, void fraction, fluid properties and plate geometry. Two different plate geometries having a corrugation angle of 27° and 63°, respectively and two different fluids (water/air and R365mfc liquid/vapor) have been analysed. A flow pattern map using the momentum flux is presented.

Transfer of hydrogen and helium through corrugated, flexible tubes

International Nuclear Information System (INIS)

Schippl, K.

2001-01-01

The transfer of liquid gas or cold gas through corrugated tubes is an alternative to rigid systems for the use in reactor technique. Advantages: flexibility for easy installation; these tubes together with their associated terminations and hardware are assembled, leak-tested and evacuated at the factory. This permits simple and cost saving installation on site. All tubes are helium leak-tested with a sensitivity of 10E -9 mbar 1/sec. Following the leak test, the vacuum space is pumped down to the operation vacuum level and properly sealed. The vacuum integrity is guaranteed as a result of the high degree of cleanliness observed during production and from the use of a specially selected better material inside the vacuum space. Disadvantage: pressure is limited to 20 bar. To fulfil all rules of the reactor safety, different tests have to be done. Because of the longitudinal weld of the corrugated tube, a bursting test of different sizes gives the best information of the liability of this kind of tube. It can be shown that the bursting pressure of such a tube is more than 5 times higher than the max. working pressure

Aeroacoustics of the swinging corrugated tube: Voice of the Dragon

NARCIS (Netherlands)

Nakiboglu, G.; Rudenko, O.; Hirschberg, Abraham

2012-01-01

When one swings a short corrugated pipe segment around one’s head, it produces a musically interesting whistling sound. As a musical toy it is called a “Hummer” and as a musical instrument, the “Voice of the Dragon.” The fluid dynamics aspects of the instrument are addressed, corresponding to the

Effects of carbon coating and pore corrugation on capillary condensation of nitrogen in SBA-15 mesoporous silica.

Science.gov (United States)

Morishige, Kunimitsu

2013-09-24

To examine the origin of an ink-bottle-like structure in SBA-15 formed by carbon coating and the effects of pore corrugation on capillary condensation and evaporation of a vapor in the cylindrical pores, we measured the adsorption isotherms of nitrogen at 77 K on 10 kinds of SBA-15 samples before and after a carbon coating process by the exposure to acetylene at 1073 K, as well as desorption scanning curves and subloops on the untreated samples. These SBA-15 samples were synthesized under the different conditions of initial SiO2/P123 ratio and hydrothermal treatment. SBA-15 with relatively large microporosity tends to form easily constrictions inside the main channels by the carbon coating. This strongly suggests that the rough pore walls of SBA-15 may induce the incomplete wetting of carbon layers on the pore walls to form the constrictions inside the cylindrical pores. A comparison of two subloops implies that the pores of SBA-15 synthesized with a SiO2/P123 ratio of 75 consist of an assembly of connecting domains of different diameters; that is, the pores are highly corrugated. For SBA-15 synthesized with a SiO2/P123 ratio of 60, the amplitude of the pore corrugation is significantly decreased by the prolonged hydrothermal treatment at 373 K. On the other hand, for SBA-15 synthesized with a SiO2/P123 ratio of 45, the amplitude of the corrugation is negligibly small, although the cylindrical pores are interconnected through narrow necks with each other. It is found that the smaller the amplitude of the pore corrugation, the smaller the width of the hysteresis loop.

Impact of interfacial imperfection on transverse wave in a functionally graded piezoelectric material structure with corrugated boundaries

Science.gov (United States)

Kumar Singh, Abhishek; Kumar, Santan; Kumari, Richa

2018-03-01

The propagation behavior of Love-type wave in a corrugated functionally graded piezoelectric material layered structure has been taken into account. Concretely, the layered structure incorporates a corrugated functionally graded piezoelectric material layer imperfectly bonded to a functionally graded piezoelectric material half-space. An analytical treatment has been employed to determine the dispersion relation for both cases of electrically open condition and electrically short condition. The phase velocity of the Love-type wave has been computed numerically and its dependence on the wave number has been depicted graphically for a specific type of corrugated boundary surfaces for both said conditions. The crux of the study lies in the fact that the imperfect bonding of the interface, the corrugated boundaries present in the layer, and the material properties of the layer and the half-space strongly influence the phase velocity of the Love-type wave. It can be remarkably noted that the imperfect bonding of the interface reduces the phase velocity of the Love-type wave significantly. As a special case of the problem, it is noticed that the procured dispersion relation for both cases of electrically open and electrically short conditions is in accordance with the classical Love wave equation.

Development of ideal solution and validation of stiffness and strength by finite element method for truss-wall corrugated cellular solids

International Nuclear Information System (INIS)

Choi, Jeong Ho; Lee, Jung Hwan; Lee, Je Hyun

2014-01-01

The objective of this study is to find the density, stiffness, and strength of truss-wall unit cell models. The diamond-corrugation, triangular-corrugation, and Navtruss-corrugation models are used for the unit cell. The ideal solutions derived for these are based on solid wall unit cell models and are developed using the Gibson-Ashby theory. To verify the ideal solutions of the models, the density, strength, and stiffness are simulated using ABAQUS software and compared with the ideal solutions on a log-log scale. The material properties of stainless steel 304 are applied. The diameter is 0.5 mm; the opening width is 0.5 mm; and the corrugation angle is 45 .deg. . Consequently, the relative Young's modulus and relative yield strength of the truss-wall unit models are good matches for the ideal expectations. It may be possible to apply a truss-wall model to diverse fields such as transportation or biomedical applications as one of the open-cell cellular solids.

Development of ideal solution and validation of stiffness and strength by finite element method for truss-wall corrugated cellular solids

Energy Technology Data Exchange (ETDEWEB)

Choi, Jeong Ho [Samjung E and W, Changwon (Korea, Republic of); Lee, Jung Hwan [Korea Institute of Materials Science,Changwon (Korea, Republic of); Lee, Je Hyun [Changwon National University, Changwon (Korea, Republic of)

2014-05-15

The objective of this study is to find the density, stiffness, and strength of truss-wall unit cell models. The diamond-corrugation, triangular-corrugation, and Navtruss-corrugation models are used for the unit cell. The ideal solutions derived for these are based on solid wall unit cell models and are developed using the Gibson-Ashby theory. To verify the ideal solutions of the models, the density, strength, and stiffness are simulated using ABAQUS software and compared with the ideal solutions on a log-log scale. The material properties of stainless steel 304 are applied. The diameter is 0.5 mm; the opening width is 0.5 mm; and the corrugation angle is 45 .deg. . Consequently, the relative Young's modulus and relative yield strength of the truss-wall unit models are good matches for the ideal expectations. It may be possible to apply a truss-wall model to diverse fields such as transportation or biomedical applications as one of the open-cell cellular solids.

Monotron and azimuthally corrugated: application to the high power microwaves generation

International Nuclear Information System (INIS)

Castro, Pedro Jose de

2003-01-01

The present document reports the activity of construction and initial operation of 6.7 GHz operation for high power microwave generation, the study on cylindrical resonators with azimuthally corrugated cross section, the determination of electrical conductivity of metallic materials and development of dielectric resonators for telecommunication applications

Measuring autogenous strain of concrete with corrugated moulds

DEFF Research Database (Denmark)

Tian, Qian; Jensen, Ole Mejlhede

2008-01-01

A reliable technique to quantify autogenous strain is a prerequisite to numerical modeling in stress calculations for high performance concrete. The introducing of a special kind of corrugated tube mould helps to transforming volume strain measurement into liner strain measurement in horizontal...... direction for fluid concrete, which not only realizes the continuous monitoring of the autogenous shrinkage since casting, but also effectively eliminates the disturbance resulting from gravity, temperature variation and mould restraint on measuring results. Based on this measuring technique, this paper...

Shear evaluation of tapered bridge girder panels with steel corrugated webs near the supports of continuous bridges

OpenAIRE

Zevallos, E.; Hassanein, M.F.; Real Saladrigas, Esther; Mirambell Arrizabalaga, Enrique

2016-01-01

Because of public construction budgets were cut over the last few years, new bridge girders with corrugated webs to reduce the construction costs have become more widely studied and used. In spite that tapered bridge girders with corrugated webs (BGCWs) are used in modern bridges, their shear strength and behaviour rarely exists in literature. Based on available literature, the web of the linearly tapered BGCWs may be divided into three typologies with different structural response to shear f...

Reversal of neuromuscular block with sugammadex: a comparison of the corrugator supercilii and adductor pollicis muscles in a randomized dose-response study.

Science.gov (United States)

Yamamoto, S; Yamamoto, Y; Kitajima, O; Maeda, T; Suzuki, T

2015-08-01

Neuromuscular monitoring using the corrugator supercilii muscle is associated with a number of challenges. The aim of this study was to assess reversal of a rocuronium-induced neuromuscular blockade with sugammadex according to monitoring either using the corrugator supercilii muscle or the adductor pollicis muscle. We hypothesized that a larger dose of sugammadex would be required to obtain a train-of-four (TOF) ratio of 1.0 with the corrugator supercilii muscle than with the adductor pollicis muscle. Forty patients aged 20-60 years and 40 patients aged ≥ 70 years were enrolled. After induction of anesthesia, we recorded the corrugator supercilii muscle response to facial nerve stimulation and the adductor pollicis muscle response to ulnar nerve stimulation using acceleromyography. All patients received 1 mg/kg rocuronium. When the first twitch (T1) of TOF recovered to 10% of control values at the corrugator supercilii, rocuronium infusion was commenced to maintain a T1 of 10% of the control at the corrugator supercilii. Immediately after discontinuation of rocuronium infusion, 2 mg/kg or 4 mg/kg of sugammadex was administered. The time for recovery to a TOF ratio of 1.0 and the number of patients not reaching a TOF ratio of 1.0 by 5 min at each dose and muscle was recorded. When neuromuscular block at the corrugator supercilii was maintained at a T1 of 10% of control, that at the adductor pollicis was deep (post-tetanic count ≤ 5). Sugammadex 4 mg/kg completely antagonized neuromuscular block at both muscles within 5 min. The time to a TOF ratio of 1.0 at the adductor pollicis was significantly longer in the group ≥ 70 years than the group 20-60 years (mean (SD): 178 (42.8) s vs. 120 (9.4) s, P sugammadex reversed neuromuscular blockade at the corrugator supercilii but not at the adductor pollicis, with 10 patients in the group 20-60 years and 8 patients in the group ≥ 70 years requiring an additional sugammadex (P�

Corrugation in the nitrogen-graphite potential probed by inelastic neutron scattering

DEFF Research Database (Denmark)

Hansen, Flemming Yssing; Frank, V. L. P.; Taub, H.

1990-01-01

-center energy gap of ∼0.4 THz in the acoustic-phonon branches is a factor of 2 larger than calculated from central atom-atom potentials. We conclude that current models of the corrugation in the adatom substrate potential greatly underestimate the lateral restoring forces in this relatively simple molecular...

Soda-Anthraquinone Durian (Durio Zibethinus Murr.) Rind Linerboard and Corrugated Medium Paper: A Preliminary Test

Science.gov (United States)

Rizal Masrol, Shaiful; Irwan Ibrahim, Mohd Halim; Adnan, Sharmiza; Mubarak Sa'adon, Amir; Ika Sukarno, Khairil; Fadrol Hisham Yusoff, Mohd

2017-08-01

A preliminary test was conducted to investigate the characteristics of linerboard and corrugated medium paper made from durian rind waste. Naturally dried durian rinds were pulped according to Soda-Anthraquinone (Soda-AQ) pulping process with a condition of 20% active alkali, 0.1% AQ, 7:1 liquor to material ratio, 120 minutes cooking time and 170°C cooking temperature. The linerboard and corrugated medium paper with a basis weight of 120 gsm were prepared and evaluated according to Malaysian International Organization for Standardization (MS ISO) and Technical Association of the Pulp and Paper Industry (TAPPI). The results indicate that the characteristics of durian rind linerboard are comparable with other wood or non-wood based paper and current commercial paper. However, low CMT value for corrugated medium and water absorptiveness quality for linerboard could be improved in future. Based on the bulk density (0.672 g/cm3), burst index (3.12 kPa.m2/g) and RCT (2.00 N.m2/g), the durian rind has shown a good potential and suitable as an alternative raw material source for linerboard industry.

Numerical Investigation of Structural Response of Corrugated Blast Wall Depending on Blast Load Pulse Shapes

Directory of Open Access Journals (Sweden)

Jung Min Sohn

Full Text Available Abstract Hydrocarbon explosions are one of most hazardous events for workers on offshore platforms. To protect structures against explosion loads, corrugated blast walls are typically installed. However, the profiles of real explosion loads are quite different depending on the congestion and confinement of Topside structures. As the level of congestion and confinement increases, the explosion load increases by up to 8 bar, and the rising time of the load decreases. This study primarily aims to investigate the structural behavior characteristics of corrugated blast walls under different types of explosion loadings. Four loading shapes were applied in the structural response analysis, which utilized a dynamic nonlinear finite element method.

Quantifying wave propagation over a corrugated metal using 5 dBi antennas

CSIR Research Space (South Africa)

Nkosi, MC

2015-09-01

Full Text Available corrugated metal of a shipping container and also in a free space. The free space measurement is used as a reference point to study the influence of the metal on the wave propagation. The transmission coefficient measured over the shipping container...

Psychometric properties of startle and corrugator response in NPU, affective picture viewing, and resting state tasks.

Science.gov (United States)

Kaye, Jesse T; Bradford, Daniel E; Curtin, John J

2016-08-01

The current study provides a comprehensive evaluation of critical psychometric properties of commonly used psychophysiology laboratory tasks/measures within the NIMH RDoC. Participants (N = 128) completed the no-shock, predictable shock, unpredictable shock (NPU) task, affective picture viewing task, and resting state task at two study visits separated by 1 week. We examined potentiation/modulation scores in NPU (predictable or unpredictable shock vs. no-shock) and affective picture viewing tasks (pleasant or unpleasant vs. neutral pictures) for startle and corrugator responses with two commonly used quantification methods. We quantified startle potentiation/modulation scores with raw and standardized responses. We quantified corrugator potentiation/modulation in the time and frequency domains. We quantified general startle reactivity in the resting state task as the mean raw startle response during the task. For these three tasks, two measures, and two quantification methods, we evaluated effect size robustness and stability, internal consistency (i.e., split-half reliability), and 1-week temporal stability. The psychometric properties of startle potentiation in the NPU task were good, but concerns were noted for corrugator potentiation in this task. Some concerns also were noted for the psychometric properties of both startle and corrugator modulation in the affective picture viewing task, in particular, for pleasant picture modulation. Psychometric properties of general startle reactivity in the resting state task were good. Some salient differences in the psychometric properties of the NPU and affective picture viewing tasks were observed within and across quantification methods. © 2016 The Authors. Psychophysiology published by Wiley Periodicals, Inc. on behalf of Society for Psychophysiological Research.

Stark effect of excitons in corrugated lateral surface superlattices: effect of centre-of-mass quantization

International Nuclear Information System (INIS)

Hong Sun

1998-11-01

The quantum confined Stark effect (QCSE) of excitons in GaAs/AlAs corrugated lateral surface superlattices (CLSSLs) is calculated. Blue and red shifts in the exciton energies are predicted for the heavy- and light-excitons in the CLSSLs, respectively, comparing with those in the unmodulated quantum well due to the different effective hole masses in the parallel direction. Sensitive dependence of the QCSE on the hole effective mass in the parallel direction is expected because of the ''centre-of-mass'' quantization (CMQ) induced by the periodic corrugated interfaces of the CLSSLs. The effect of the CMQ on the exciton mini-bands and the localization of the excitons in the CLSSLs is discussed. (author)

Measurement with corrugated tubes of early-age autogenous shrinkage of cement-based material

DEFF Research Database (Denmark)

Tian, Qian; Jensen, Ole Mejlhede

2009-01-01

The use of a special corrugated mould enables transformation of volume strain into horizontal, linear strain measurement in the fluid stage. This allows continuous measurement of the autogenous shrinkage of cement-based materials since casting, and also effectively eliminates unwanted influence...

Swimming behaviour and ascent paths of brook trout in a corrugated culvert

Science.gov (United States)

Goerig, Elsa; Bergeron, Normand E.; Castro-Santos, Theodore R.

2017-01-01

Culverts may restrict fish movements under some hydraulic conditions such as shallow flow depths or high velocities. Although swimming capacity imposes limits to passage performance, behaviour also plays an important role in the ability of fish to overcome velocity barriers. Corrugated metal culverts are characterized by unsteady flow and existence of low‐velocity zones, which can improve passage success. Here, we describe swimming behaviour and ascent paths of 148 wild brook trout in a 1.5‐m section of a corrugated metal culvert located in Raquette Stream, Québec, Canada. Five passage trials were conducted in mid‐August, corresponding to specific mean cross‐sectional flow velocities ranging from 0.30 to 0.63 m/s. Fish were individually introduced to the culvert and their movements recorded with a camera located above the water. Lateral and longitudinal positions were recorded at a rate of 3 Hz in order to identify ascent paths. These positions were related to the distribution of flow depths and velocities in the culvert. Brook trout selected flow velocities from 0.2 to 0.5 m/s during their ascents, which corresponded to the available flow velocities in the culvert at the low‐flow conditions. This however resulted in the use of low‐velocity zones at higher flows, mainly located along the walls of the culvert. Some fish also used the corrugations for sheltering, although the behaviour was marginal and did not occur at the highest flow condition. This study improves knowledge on fish behaviour during culvert ascents, which is an important aspect for developing reliable and accurate estimates of fish passage ability.

Spoof surface plasmon modes on doubly corrugated metal surfaces at terahertz frequencies

International Nuclear Information System (INIS)

Liu, Yong-Qiang; Kong, Ling-Bao; Du, Chao-Hai; Liu, Pu-Kun

2016-01-01

Spoof surface plasmons (SSPs) have many potential applications such as imaging and sensing, communications, innovative leaky wave antenna and many other passive devices in the microwave and terahertz (THz) spectrum. The extraordinary properties of SSPs (e.g. extremely strong near field, enhanced beam–wave interaction) make them especially attractive for developing novel THz electronic sources. SSP modes on doubly corrugated metal surfaces are investigated and analyzed both theoretically and numerically in this paper. The analytical SSP dispersion expressions of symmetric and anti-symmetric modes are obtained with a simplified modal field expansion method; the results are also verified by the finite integration method. Additionally, the propagation losses are also considered for real copper surfaces with a limited constant conductivity in a THz regime. It is shown that the asymptotical frequency of the symmetric mode at the Brillouin boundary decreases along with the decreased gap size between these two corrugated metal surfaces while the asymptotical frequency increases for the anti-symmetric mode. The anti-symmetric mode demonstrates larger propagation losses than the symmetric mode. Further, the losses for both symmetric and anti-symmetric modes decrease when this gap size enlarges. By decreasing groove depth, the asymptotical frequency increases for both the symmetric and the anti-symmetric mode, but the variation of propagation losses is more complicated. Propagation losses increase along with the increased period. Our studies on the dispersion characteristics and propagation losses of SSP modes on this doubly corrugated metallic structure with various parameters is instructive for numerous applications such as waveguides, circuitry systems with high integration, filters and powerful electronic sources in the THz regime. (paper)

Performance analysis of solar air heater with jet impingement on corrugated absorber plate

Directory of Open Access Journals (Sweden)

Alsanossi M. Aboghrara

2017-09-01

Full Text Available This paper deals with the experimental investigation outlet temperature and efficiency, of Solar Air heater (SAH. The experimental test set up designed and fabricated to study the effect of jet impingement on the corrugated absorber plate, through circular jets in a duct flow of solar air heater, and compared with conventional solar air heater on flat plat absorber. Under effect of mass flow rate (ṁ of air and solar radiation on outlet air temperature, and efficiency, are analyzed. Results show the flow jet impingement on corrugated plat absorber is a strong function of heat transfer enhancement. The present investigation concludes that the mass flow rate of air substantially influences the heat transfer on solar air heaters. And the thermal efficiency of proposed design duct is observed almost 14% more as compare to the smooth duct. At solar radiation 500–1000 (W/M2, 308 K ambient temperature and 0.01–0.03 (Kg/S mass flow rate

Improvement of heat transfer by the use of corrugated surfaces; Amelioration du transfert de chaleur par l'emploi de surfaces corruguees

Energy Technology Data Exchange (ETDEWEB)

Gargaud, J; Paumard, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-07-01

This experimental work is designed to determine the friction coefficient and the Margoulis number of internally or externally corrugated cans cooled by air or CO{sub 2} under forced convection, when the Reynolds' number is between 1.5 * 10{sup 4} and 3.5 * 10{sup 6} Different corrugation profiles have been examined; they are made up of variously shaped threading, of rings, of transverse fins, of very small 'herring-bone fins, of undulations. Two types of test have been carried out: 1. tests in annular spaces using CO{sub 2} or air, where the gas circulates between an electrically heated corrugated nucleus having a constant flux and a smooth exterior channel. 2. tests on internally corrugated tubes heated by an external water current and cooled by an internal current of pressurized CO{sub 2}. The first type of test requires probe-measurement of the speeds and the temperatures in the fluid in order to obtain a friction coefficient and a Margoulis' number which are characteristic of the corrugated surface. These coefficients, on the other hand, are given directly by the second, type of test. This work shows the role and the importance of the various geometric and aerodynamic parameters such as relative roughness, the reduced pitch (ratio of the pitches at the height of the corrugation) and the Reynolds' number. (authors) [French] Ce travail experimental a pour objet la determination du coefficient de frottement et du nombre de Margoulis de gaines corruguees exterieurement ou interieurement, refroidies par de l'air ou du CO{sub 2} en convection forcee turbulente, pour des nombres de Reynolds compris entre 1,5.10{sup 4} et 3,5.10{sup 6}. Divers profils de corrugations ont ete examines; ils comprennent des filetages de formes variees, des anneaux, des ailettes transversales et des ailettes en chevrons de tres petites dimensions, des ondulations. Deux types d'essais ont ete realises: 1. des essais en espace annulaire, au CO{sub 2} ou a l'air, ou le gaz circule entre un

Modeling of the plastic flow kinematics in the forming process of the lightweight flange corrugation

Directory of Open Access Journals (Sweden)

I. V. Fomenko

2012-01-01

Full Text Available The determination of the forming maximum possibilities of the flange corrugation by stretching with a free movement of the billets end in the rigid sectional matrices detachable by the flexible filler.

Heat transfer and pressure drop studies of TiO2/DI water nanofluids in helically corrugated tubes using spiraled rod inserts

Science.gov (United States)

Anbu, S.; Venkatachalapathy, S.; Suresh, S.

2018-05-01

An experimental study on the convective heat transfer and friction factor characteristics of TiO2/DI water nanofluids in uniformly heated plain and helically corrugated tubes (HCT) with and without spiraled rod inserts (SRI) under laminar flow regime is presented in this paper. TiO2 nanoparticles with an average size of 32 nm are dispersed in deionized (DI) water to form stable suspensions containing 0.1, 0.15, 0.2, and 0.25% volume concentrations of nanoparticles. It is found that the inclusion of nanoparticles to DI water ameliorated Nusselt number which increased with nanoparticles concentration upto 0.2%. Two spiraled rod inserts made of copper with different pitches (pi = 50 mm and 30 mm) are inserted in both plain and corrugated tubes and it is found that the addition of these inserts increased the Nusselt number substantially. For Helically corrugated tube with lower pitch and maximum height of corrugation (pc = 8 mm, hc = 1 mm) with 0.2% volume concentration of nanoparticles, a maximum enhancement of 15% in Nusselt number is found without insert and with insert having lower pitch (pi = 30 mm) the enhancement is 34% when compared to DI water in plain tube. The results on friction factor show a maximum penalty of about 53.56% for the above HCT.

Improving indoor air quality by using the new generation of corrugated cardboard-based filters.

Science.gov (United States)

Candiani, Gabriele; Del Curto, Barbara; Cigada, Alberto

2012-09-27

Indoor Air Quality (IAQ) is strictly affected by the concentration of total suspended particulate matter (TSP). Air filtration is by far the most feasible suggestion to improve IAQ. Unfortunately, highly effective HEPA filters also have a few major weaknesses that have hindered their widespread use. There is therefore a renewed interest in developing novel, cost-effective filtration systems. We have recently reported the development of cardboard-based filters for bacterial removal that were further implemented and tested herein. A parallelepiped filter manufactured by aligning strips of corrugated cardboard and surrounded by a cardboard frame was specifically designed with an internal pocket holding a partially cut antistatic pleated fabric (HP). This filter, together with its parent version (CTRL) and a commercially sourced specimen (CAF), were assessed comparatively in a long-time test to assess their effectiveness on TSP removal. We found that the TSP abatement efficiency (E%) of the HP filter was relatively high and invariable over the 93 days of test and the pressure drop (PD%) decrease because of filter clogging was moderate. Most important, the HP filter was the most effective if assessed in terms of overall yield (Y%) and its performance was quite constant over the entire period considered. This work disclosed this novel class of corrugated cardboard-based filters as promising tools to ameliorate IAQ in light of their good TSP removal properties that endure over time. Moreover, cardboard is a lightweight, inexpensive, and eco-friendly material and corrugated cardboard-based air filters are very easy to shape and mount on and/or replace in existing ventilation systems.

Ohmic losses in coaxial resonators with longitudinal inner-outer corrugation

Energy Technology Data Exchange (ETDEWEB)

Shenyong Hou, A. [Terahertz Science and Technology Research Center, University of Electronics Science and Technology of China, Chengdu 610054 (China); Yangtze Normal University, Chongqing 408001 (China); Sheng Yu, B.; Hongfu Li, C.; Qixiang Zhao, D. [Terahertz Science and Technology Research Center, University of Electronics Science and Technology of China, Chengdu 610054 (China); Xiang Li, E. [Terahertz Science and Technology Research Center, University of Electronics Science and Technology of China, Chengdu 610054 (China); Queen Mary University of London, London E1 4NS (United Kingdom)

2013-05-15

In this paper, a coaxial resonator with longitudinal inner-outer corrugation is introduced. Its eigen-equation and expression of ohmic losses are derived. Ohmic losses in the cavity are investigated. Results show that ohmic losses in the outer and inner conductors share a similar variation trend, while the former is larger than the later. What's more, changes of the inner and outer slot depth and width induce different variations of ohmic losses on the surface of the inner and outer conductors.

Dispersion of helically corrugated waveguides: Analytical, numerical, and experimental study

International Nuclear Information System (INIS)

Burt, G.; Ronald, K.; Young, A.R.; Phelps, A.D.R.; Cross, A.W.; Konoplev, I.V.; He, W.; Thomson, J.; Whyte, C.G.; Samsonov, S.V.; Denisov, G.G.; Bratman, V.L.

2004-01-01

Helically corrugated waveguides have recently been studied for use in various applications such as interaction regions in gyrotron traveling-wave tubes and gyrotron backward-wave oscillators and as a dispersive medium for passive microwave pulse compression. The paper presents a summary of various methods that can be used for analysis of the wave dispersion of such waveguides. The results obtained from an analytical approach, simulations with the three-dimensional numerical code MAGIC, and cold microwave measurements are analyzed and compared

Emission Characteristics of Organic Light-Emitting Diodes and Organic Thin-Films with Planar and Corrugated Structures

Directory of Open Access Journals (Sweden)

Mao-Kuo Wei

2010-04-01

Full Text Available In this paper, we review the emission characteristics from organic light-emitting diodes (OLEDs and organic molecular thin films with planar and corrugated structures. In a planar thin film structure, light emission from OLEDs was strongly influenced by the interference effect. With suitable design of microcavity structure and layer thicknesses adjustment, optical characteristics can be engineered to achieve high optical intensity, suitable emission wavelength, and broad viewing angles. To increase the extraction efficiency from OLEDs and organic thin-films, corrugated structure with micro- and nano-scale were applied. Microstructures can effectively redirects the waveguiding light in the substrate outside the device. For nanostructures, it is also possible to couple out the organic and plasmonic modes, not only the substrate mode.

Removal of VOCs from air stream with corrugated sheet as adsorbent

Directory of Open Access Journals (Sweden)

Rabia Arshad

2016-10-01

Full Text Available A large proportional of volatile organic compounds (VOCs are released into the environment from various industrial processes. The current study elucidates an application of a simple adsorption phenomenon for removal of three main types of VOCs, i.e., benzene, xylene and toluene, from an air stream. Two kinds of adsorbents namely acid digested adsorbent and activated carbon are prepared to assess the removal efficiency of each adsorbent in the indoor workplace environment. The results illustrate that the adsorbents prepared from corrugated sheets were remarkably effective for the removal of each pollutant type. Nevertheless, activated carbon showed high potential of adsorbing the targeted VOC compared to the acid digested adsorbent. The uptake by the adsorbents was in the following order: benzene > xylene > toluene. Moreover, maximum adsorption of benzene, toluene and xylene occurred at 20 °C and 1.5 cm/s for both adsorbents whereas minimum success was attained at 30 °C and 1.0 cm/s. However, adsorption pattern are found to be similar for each of the the three aromatic hydrocarbons. It is concluded that the corrugated sheets waste can be a considered as a successful and cost-effective solution towards effective removal of targeted pollutants in the air stream.

Mass transport enhancement in redox flow batteries with corrugated fluidic networks

Science.gov (United States)

Lisboa, Kleber Marques; Marschewski, Julian; Ebejer, Neil; Ruch, Patrick; Cotta, Renato Machado; Michel, Bruno; Poulikakos, Dimos

2017-08-01

We propose a facile, novel concept of mass transfer enhancement in flow batteries based on electrolyte guidance in rationally designed corrugated channel systems. The proposed fluidic networks employ periodic throttling of the flow to optimally deflect the electrolytes into the porous electrode, targeting enhancement of the electrolyte-electrode interaction. Theoretical analysis is conducted with channels in the form of trapezoidal waves, confirming and detailing the mass transport enhancement mechanism. In dilute concentration experiments with an alkaline quinone redox chemistry, a scaling of the limiting current with Re0.74 is identified, which compares favourably against the Re0.33 scaling typical of diffusion-limited laminar processes. Experimental IR-corrected polarization curves are presented for high concentration conditions, and a significant performance improvement is observed with the narrowing of the nozzles. The adverse effects of periodic throttling on the pumping power are compared with the benefits in terms of power density, and an improvement of up to 102% in net power density is obtained in comparison with the flow-by case employing straight parallel channels. The proposed novel concept of corrugated fluidic networks comes with facile fabrication and contributes to the improvement of the transport characteristics and overall performance of redox flow battery systems.

Simulation and analysis on ultrasonic testing for the cement grouting defects of the corrugated pipe

Energy Technology Data Exchange (ETDEWEB)

Qingbang, Han; Ling, Chen; Changping, Zhu [Changzhou Key Laboratory of Sensor Networks and Environmental Sensing, College of IOT, Hohai University Changzhou, Jiangsu, 213022 (China)

2014-02-18

The defects exist in the cement grouting process of prestressed corrugated pipe may directly impair the bridge safety. In this paper, sound fields propagation in concrete structures with corrugated pipes and the influence of various different defects are simulated and analyzed using finite element method. The simulation results demonstrate a much complex propagation characteristic due to multiple reflection, refraction and scattering, where the scattering signals caused by metal are very strong, while the signals scattered by an air bubble are weaker. The influence of defect both in time and frequency domain are found through deconvolution treatment. In the time domain, the deconvolution signals correspond to larger defect display a larger head wave amplitude and shorter arrive time than those of smaller defects; in the frequency domain, larger defect also shows a stronger amplitude, lower center frequency and lower cutoff frequency.

Simulation and analysis on ultrasonic testing for the cement grouting defects of the corrugated pipe

International Nuclear Information System (INIS)

Qingbang, Han; Ling, Chen; Changping, Zhu

2014-01-01

The defects exist in the cement grouting process of prestressed corrugated pipe may directly impair the bridge safety. In this paper, sound fields propagation in concrete structures with corrugated pipes and the influence of various different defects are simulated and analyzed using finite element method. The simulation results demonstrate a much complex propagation characteristic due to multiple reflection, refraction and scattering, where the scattering signals caused by metal are very strong, while the signals scattered by an air bubble are weaker. The influence of defect both in time and frequency domain are found through deconvolution treatment. In the time domain, the deconvolution signals correspond to larger defect display a larger head wave amplitude and shorter arrive time than those of smaller defects; in the frequency domain, larger defect also shows a stronger amplitude, lower center frequency and lower cutoff frequency

Corrugated structure insertion for extending the SASE bandwidth up to 3% at the European XFEL

International Nuclear Information System (INIS)

Zagorodnov, I.; Feng, G.; Limberg, T.

2016-07-01

The usage of X-ray free electron laser (XFEL) in femtosecond nanocrystallography involves sequential illumination of many small crystals of arbitrary orientation. Hence a wide radiation bandwidth will be useful in order to obtain and to index a larger number of Bragg peaks used for determination of the crystal orientation. Considering the baseline configuration of the European XFEL in Hamburg, and based on beam dynamics simulations, we demonstrate here that the usage of corrugated structures allows for a considerable increase in radiation bandwidth. Data collection with a 3% bandwidth, a few microjoule radiation pulse energy, a few femtosecond pulse duration, and a photon energy of 5.4 keV is possible. For this study we have developed an analytical modal representation of the short-range wake function of the flat corrugated structures for arbitrary offsets of the source and the witness particles.

Corrugated structure insertion for extending the SASE bandwidth up to 3% at the European XFEL

Energy Technology Data Exchange (ETDEWEB)

Zagorodnov, I.; Feng, G.; Limberg, T.

2016-07-15

The usage of X-ray free electron laser (XFEL) in femtosecond nanocrystallography involves sequential illumination of many small crystals of arbitrary orientation. Hence a wide radiation bandwidth will be useful in order to obtain and to index a larger number of Bragg peaks used for determination of the crystal orientation. Considering the baseline configuration of the European XFEL in Hamburg, and based on beam dynamics simulations, we demonstrate here that the usage of corrugated structures allows for a considerable increase in radiation bandwidth. Data collection with a 3% bandwidth, a few microjoule radiation pulse energy, a few femtosecond pulse duration, and a photon energy of 5.4 keV is possible. For this study we have developed an analytical modal representation of the short-range wake function of the flat corrugated structures for arbitrary offsets of the source and the witness particles.

Characterization of low-frequency acoustic wave propagation through a periodic corrugated waveguide

Science.gov (United States)

Jiang, Changyong; Huang, Lixi

2018-03-01

In this paper, a periodic corrugated waveguide structure is proposed, and its unit-cell is analyzed by the wave finite element method. In low-frequency range, the unit-cell is treated as an equivalent fluid through a homogenization process, and the equivalent acoustic parameters are obtained, which are validated by finite structure simulations and experiments. The proposed structure is shown to add tortuosity to the waveguide, hence higher equivalent fluid density is achieved, while the system elastic modulus remains unchanged. As a result, the equivalent speed of sound is smaller than normal air. The application of such change of speed of sound is demonstrated in the classic quarter-wavelength resonator based on the corrugated waveguide, which gives a lower resonance frequency with the same side branch length. When the waveguide is filled with porous materials, the added tortuosity enhances the broadband, low-frequency sound absorption by increasing the equivalent mass without bringing in excess damping, the latter being partly responsible for the poor performance of usual porous materials in the low-frequency region. Therefore, the proposed structure provides another dimension for the design and optimization of porous sound absorption materials.

A technology to improve formability for aluminum alloy thin-wall corrugated sheet component hydroforming

Directory of Open Access Journals (Sweden)

Lang Lihui

2015-01-01

Full Text Available The explosively forming projectile (EFP had been traditional adopted for the aluminum thin-walled corrugated sheet, whose deformation range is large but the formability is poor, and this process usually has problems of poor surface quality, long manufacturing cycle and high cost. The active hydroforming process was suggested to solve these issues during EFP. A new technology named as blank bulging by turning the upside down active hydroforming technology was proposed to overcome difficulties in non-uniform thickness distribution and cracking failure of corrugated sheet during the conventional hydroforming process. Both numerical simulations and experiments were conducted for this new technology. The result show that the deformation capacity of aluminum alloys can be improved effectively, and the more uniform distribution of wall thickness was obtained by this new method. It is conducted that the new method is universal for thin-walled, shallow drawing parts with complex section.

Numerical Simulation of Turbulent Half-corrugated Channel Flow by Hydrophilic and Hydrophobic Surfaces

Directory of Open Access Journals (Sweden)

M. R. Rastan

2018-03-01

Full Text Available In the first part of the present study, a two dimensional half-corrugated channel flow is simulated at Reynolds number of 104, in no-slip condition (hydrophilic surfaces( using various low Reynolds turbulence models as well as standard k-ε model; and an appropriate turbulence model (k-ω 1998 model( is proposed. Then, in order to evaluate the proposed solution method in simulation of flow adjacent to hydrophobic surfaces, turbulent flow is simulated in simple channel and the results are compared with the literature. Finally, two dimensional half-corrugated channel flow at Reynolds number of 104 is simulated again in vicinity of hydrophobic surfaces for varoius slip lengths. The results show that this method is capable of drag reduction in such a way that an increase of 200 μm in slip length leads to a massive drag reduction up to 38%. In addition, to access a significant drag reduction in turbulent flows, the non-dimensionalized slip length should be larger than the minimum.

Growth of InP directly on Si by corrugated epitaxial lateral overgrowth

International Nuclear Information System (INIS)

Metaferia, Wondwosen; Kataria, Himanshu; Sun, Yan-Ting; Lourdudoss, Sebastian

2015-01-01

In an attempt to achieve an InP–Si heterointerface, a new and generic method, the corrugated epitaxial lateral overgrowth (CELOG) technique in a hydride vapor phase epitaxy reactor, was studied. An InP seed layer on Si (0 0 1) was patterned into closely spaced etched mesa stripes, revealing the Si surface in between them. The surface with the mesa stripes resembles a corrugated surface. The top and sidewalls of the mesa stripes were then covered by a SiO 2 mask after which the line openings on top of the mesa stripes were patterned. Growth of InP was performed on this corrugated surface. It is shown that growth of InP emerges selectively from the openings and not on the exposed silicon surface, but gradually spreads laterally to create a direct interface with the silicon, hence the name CELOG. We study the growth behavior using growth parameters. The lateral growth is bounded by high index boundary planes of {3 3 1} and {2 1 1}. The atomic arrangement of these planes, crystallographic orientation dependent dopant incorporation and gas phase supersaturation are shown to affect the extent of lateral growth. A lateral to vertical growth rate ratio as large as 3.6 is achieved. X-ray diffraction studies confirm substantial crystalline quality improvement of the CELOG InP compared to the InP seed layer. Transmission electron microscopy studies reveal the formation of a direct InP–Si heterointerface by CELOG without threading dislocations. While CELOG is shown to avoid dislocations that could arise due to the large lattice mismatch (8%) between InP and Si, staking faults could be seen in the layer. These are probably created by the surface roughness of the Si surface or SiO 2 mask which in turn would have been a consequence of the initial process treatments. The direct InP–Si heterointerface can find applications in high efficiency and cost-effective Si based III–V semiconductor multijunction solar cells and optoelectronics integration. (paper)

Dual nature of localization in guiding systems with randomly corrugated boundaries: Anderson-type versus entropic

International Nuclear Information System (INIS)

Tarasov, Yu.V.; Shostenko, L.D.

2015-01-01

A unified theory for the conductance of an infinitely long multimode quantum wire whose finite segment has randomly rough lateral boundaries is developed. It enables one to rigorously take account of all feasible mechanisms of wave scattering, both related to boundary roughness and to contacts between the wire rough section and the perfect leads within the same technical frameworks. The rough part of the conducting wire is shown to act as a mode-specific randomly modulated effective potential barrier whose height is governed essentially by the asperity slope. The mean height of the barrier, which is proportional to the average slope squared, specifies the number of conducting channels. Under relatively small asperity amplitude this number can take on arbitrary small, up to zero, values if the asperities are sufficiently sharp. The consecutive channel cut-off that arises when the asperity sharpness increases can be regarded as a kind of localization, which is not related to the disorder per se but rather is of entropic or (equivalently) geometric origin. The fluctuating part of the effective barrier results in two fundamentally different types of guided wave scattering, viz., inter- and intramode scattering. The intermode scattering is shown to be for the most part very strong except in the cases of (a) extremely smooth asperities, (b) excessively small length of the corrugated segment, and (c) the asperities sharp enough for only one conducting channel to remain in the wire. Under strong intermode scattering, a new set of conducting channels develops in the corrugated waveguide, which have the form of asymptotically decoupled extended modes subject to individual solely intramode random potentials. In view of this fact, two transport regimes only are realizable in randomly corrugated multimode waveguides, specifically, the ballistic and the localized regime, the latter characteristic of one-dimensional random systems. Two kinds of localization are thus shown to

Theory and Monte-Carlo simulation of adsorbates on corrugated surfaces

DEFF Research Database (Denmark)

Vives, E.; Lindgård, P.-A.

1993-01-01

-phase between the commensurate and incommensurate phase stabilized by defects. Special attention has been given to the study of the epitaxial rotation angles of the different phases. Available experimental data is in agreement with the simulations and with a general theory for the epitaxial rotation which takes......Phase transitions in systems of adsorbed molecules on corrugated surfaces are studied by means of Monte Carlo simulation. Particularly, we have studied the phase diagram of D2 on graphite as a function of coverage and temperature. We have demonstrated the existence of an intermediate gamma...

Spoof surface plasmons propagating along a periodically corrugated coaxial waveguide

International Nuclear Information System (INIS)

Talebi, Nahid; Shahabadi, Mahmoud

2010-01-01

Using the rigorous mode-matching technique, we have investigated a periodically corrugated perfectly conducting coaxial waveguide for the possibility of propagation of localized spoof surface plasmons. To verify our results, the computed band diagram of the structure has been compared with the one obtained using the body-of-revolution finite-difference time-domain method. The obtained spoof surface plasmon modes have been shown to be highly localized and slowly propagating. Variations of the obtained modal frequencies and mode profiles as a function of the depth and width of the grooves have also been investigated.

Spoof surface plasmons propagating along a periodically corrugated coaxial waveguide

Energy Technology Data Exchange (ETDEWEB)

Talebi, Nahid; Shahabadi, Mahmoud, E-mail: n.talebi@ece.ut.ac.i [Photonics Research Laboratory, Center of Excellence for Applied Electromagnetic Systems, School of Electrical and Computer Engineering, University of Tehran, North Kargar Ave., Tehran (Iran, Islamic Republic of)

2010-04-07

Using the rigorous mode-matching technique, we have investigated a periodically corrugated perfectly conducting coaxial waveguide for the possibility of propagation of localized spoof surface plasmons. To verify our results, the computed band diagram of the structure has been compared with the one obtained using the body-of-revolution finite-difference time-domain method. The obtained spoof surface plasmon modes have been shown to be highly localized and slowly propagating. Variations of the obtained modal frequencies and mode profiles as a function of the depth and width of the grooves have also been investigated.

KEMAMPUAN GENTENG PLASTIK BERGELOMBANG (CORRUGATED PLASTIC SEBAGAI BIOFILTER PARTIKEL AMONIAK DAN BAHAN ORGANIK DI MEDIA BUDIDAYA DAN LIMBAH CAIR BUDIDAYA IKAN (Performance of Corrugated Plastic as Biofilter of Ammonia Particle and Organic Material

Directory of Open Access Journals (Sweden)

Muslim Muslim

2010-07-01

Full Text Available ABSTRAK Pertumbuhan budidaya ikan dalam beberapa dekade ini berkembang sangat pesat, hal ini karena permintaan akan ikan meningkat. Meningkatnya kegiatan budidaya ikan selalu diiringi dengan meningkatnya limbah yang dihasilkan. Hal ini akan sangat cepat berpengaruh bila sistem budidaya yang dipakai adalah semi intesif atau intensif. Limbah tersebut harus segera dihilangkan atau dikurangi, karena akan berdampak pada ikan yang dibudidaya dan lingkungan seperti sungai dan laut. Tujuan penelitian ini adalah ingin mengetahui kemampuan genteng plastik bergelombang mengurangi limbah yang dihasilkan budidaya ikan yaitu Total Suspended Sediment (TSS, Suspended Sediment (SS, amoniak dan bahan organik (COD. Dari hasil penelitian diperoleh bahwa air limbah budidaya ikan yang mengandung TSS, SS, amoniak dan bahan organik setelah dilewatkan dengan genteng plastik bergelombang konsentrasinya menurun dengan tingkat efisiensi pengurangan yang terjadi di dalam kolam ikan dan di luar kolam ikan adalah sebagai berikut: 74,51% dan 54,42% (TSS; 39,20% dan 49,12% (SS; 19,82% dan 14,2% (amoniak; dan 24,82% dan 22,47% (COD. Ternyata genteng plastik bergelombang mempunyai tingkat pengurangan (g/m3/hr dan tingkat pengurangan spesifik (mg/m2/hr terhadap kandungan amoniak lebih efektif bila dibandingkan dengan material lain seperti plastic rolls, scrub pads, pipa PVC dan lain sebagainya.   ABSTRACT Aquaculture has been developing rapidly during the last few decades; it is due to the increase of fish demand. Increasing aquaculture activities especially with semi-intensive and intensive system have significant effect on waste production, which has to be removed or to be reduced quickly because will effect on fish in rearing tank and environment when through away to environment such as river and sea. The objectives of this study were to know the capability of corrugated plastic to remove or to reduce wastes content produced by aquaculture activities, i.e, Total Suspended

Trend extraction of rail corrugation measured dynamically based on the relevant low-frequency principal components reconstruction

International Nuclear Information System (INIS)

Li, Yanfu; Liu, Hongli; Ma, Ziji

2016-01-01

Rail corrugation dynamic measurement techniques are critical to guarantee transport security and guide rail maintenance. During the inspection process, low-frequency trends caused by rail fluctuation are usually superimposed on rail corrugation and seriously affect the assessment of rail maintenance quality. In order to extract and remove the nonlinear and non-stationary trends from original mixed signals, a hybrid model based ensemble empirical mode decomposition (EEMD) and modified principal component analysis (MPCA) is proposed in this paper. Compared with the existing de-trending methods based on EMD, this method first considers low-frequency intrinsic mode functions (IMFs) thought to be underlying trend components that maybe contain some unrelated components, such as white noise and low-frequency signal itself, and proposes to use PCA to accurately extract the pure trends from the IMFs containing multiple components. On the other hand, due to the energy contribution ratio between trends and mixed signals is prior unknown, and the principal components (PCs) decomposed by PCA are arranged in order of energy reduction without considering frequency distribution, the proposed method modifies traditional PCA and just selects relevant low-frequency PCs to reconstruct the trends based on the zero-crossing numbers (ZCN) of each PC. Extensive tests are presented to illustrate the effectiveness of the proposed method. The results show the proposed EEMD-PCA-ZCN is an effective tool for trend extraction of rail corrugation measured dynamically. (paper)

Squeezing Molecularly thin Lubricant Films between curved Corrugated Surfaces with long range Elasticity

DEFF Research Database (Denmark)

Sivebæk, Ion Marius; Samoilov, Vladimir N.; Persson, Bo N. J.

2010-01-01

3H8, C4H10, C8H18, C9H20, C10H22, C14H30 and C16H34, confined between corrugated gold surfaces. Well defined molecular layers develop in the lubricant film when the width is of the order of a few atomic diameters. An external squeezing pressure induces discontinuous, thermally activated changes...

Uses of four-fold coaxial corrugated piping in low temperature technology

Energy Technology Data Exchange (ETDEWEB)

Beck, A; Rohner, P [Kabel- und Metallwerke Gutehoffnungshuette A.G., Hannover (Germany, F.R.)

1978-06-01

The increasing uses of superconducting equipment in various areas of research and technology, including even medicine, create an increasing demand for suitable transfer lines for liquid helium which still remains practically the only suitable coolant. This paper reports on flexible four-fold coaxial corrugated piping lines which can combine a forword flow and a return flow channel for the coolant and which can be designed for various operating conditions. The mechanical and thermal properties of such piping lines are discussed.

Corrugation of Phase-Separated Lipid Bilayers Supported by Nanoporous Silica Xerogel Surfaces

Energy Technology Data Exchange (ETDEWEB)

Goksu, E I; Nellis, B A; Lin, W; Satcher Jr., J H; Groves, J T; Risbud, S H; Longo, M L

2008-10-30

Lipid bilayers supported by substrates with nanometer-scale surface corrugations holds interest in understanding both nanoparticle-membrane interactions and the challenges of constructing models of cell membranes on surfaces with desirable properties, e.g. porosity. Here, we successfully form a two-phase (gel-fluid) lipid bilayer supported by nanoporous silica xerogel. Surface topology, diffusion, and lipid density in comparison to mica-supported lipid bilayers were characterized by AFM, FRAP, FCS, and quantitative fluorescence microscopy, respectively. We found that the two-phase lipid bilayer follows the xerogel surface contours. The corrugation imparted on the lipid bilayer results in a lipid density that is twice that on a flat mica surface. In direct agreement with the doubling of actual bilayer area in a projected area, we find that the lateral diffusion coefficient (D) of lipids on xerogel ({approx}1.7 {micro}m{sup 2}/s) is predictably lower than on mica ({approx}4.1 {micro}m{sup 2}/s) by both FRAP and FCS techniques. Furthermore, the gel-phase domains on xerogel compared to mica were larger and less numerous. Overall, our results suggest the presence of a relatively defect-free continuous two-phase bilayer that penetrates approximately midway into the first layer of {approx}50 nm xerogel beads.

Thermal-Hydraulic Performance of a Corrugated Cooling Fin with Louvered Surfaces

DEFF Research Database (Denmark)

Sønderby, Simon Kaltoft; Hosseini, Seyed Mojtaba Mir; Rezaniakolaei, Alireza

2017-01-01

The main objective of the article is to investigate thermal-hydraulic performance of a corrugated cooling fin with louvered surfaces. The investigation is carried out using the fin geometry of one most commonly used liquid-to-air heat exchangers. The investigation was carried out by numerically...... simulating the airflow with louvered fin geometry. The simulation model was verified by comparing simulated j- and f-factors with the corresponding values of several experimental correlations. The j-factors deviated less than 10.7 % from two of the experimental correlations, whereas deviations ranging...

Design and Realization Aspects of 1-THz Cascade Backward Wave Amplifier Based on Double Corrugated Waveguide

DEFF Research Database (Denmark)

Paoloni, Claudio; Di Carlo, Aldo; Bouamrane, Fayçal

2013-01-01

The design and fabrication challenges in the first ever attempt to realize a 1-THz vacuum tube amplifier are described. Implementation of innovative solutions including a slow-wave structure in the form of a double corrugated waveguide, lateral tapered input and output couplers, deep X-ray LIGA f...

Thin polymer films on chemically patterned, corrugated substrates

International Nuclear Information System (INIS)

Geoghegan, Mark; Wang Chun; Rehse, Nicolaus; Magerle, Robert; Krausch, Georg

2005-01-01

We study the effect of a chemical pattern on the wetting and dewetting behaviour of thin polystyrene (PS) films on regularly corrugated silicon substrates. Our results reveal that the film preparation, annealing method, and confinement play a critical role in the final film structure. On evaporating gold on both sides of the facets (such that it covered the crests of the facets, and not the troughs), we observed dewetting, which proceeded to the gold, demonstrating an enthalpic effect contrary to the outcome previously observed when gold was only evaporated on one side of the facet. We also coated the substrate with octadecyltrichlorosilane (OTS); this led to a gold and OTS striped structure. PS films several nanometres thick dewet such substrates, with a preferential direction for dewetting in the direction of the stripes forming droplets of a considerably larger size than the stripes

Modeling noncontact atomic force microscopy resolution on corrugated surfaces

Directory of Open Access Journals (Sweden)

Kristen M. Burson

2012-03-01

Full Text Available Key developments in NC-AFM have generally involved atomically flat crystalline surfaces. However, many surfaces of technological interest are not atomically flat. We discuss the experimental difficulties in obtaining high-resolution images of rough surfaces, with amorphous SiO2 as a specific case. We develop a quasi-1-D minimal model for noncontact atomic force microscopy, based on van der Waals interactions between a spherical tip and the surface, explicitly accounting for the corrugated substrate (modeled as a sinusoid. The model results show an attenuation of the topographic contours by ~30% for tip distances within 5 Å of the surface. Results also indicate a deviation from the Hamaker force law for a sphere interacting with a flat surface.

Mitigation of biofilm formation on corrugated cardboard fresh produce packaging surfaces using a novel thiazolidinedione derivative integrated in acrylic emulsion polymers

Directory of Open Access Journals (Sweden)

Michael eBrandwein

2016-02-01

Full Text Available Various surfaces associated with the storage and packing of food are known to harbor distinct bacterial pathogens. Conspicuously absent among the plethora of studies implicating food packaging materials and machinery is the study of corrugated cardboard packaging, the worldwide medium for transporting fresh produce. In this study, we observed the microbial communities of three different store-bought fruits and vegetables, along with their analogue cardboard packaging using high throughput sequencing technology. We further developed an anti-biofilm polymer meant to coat corrugated cardboard surfaces and mediate bacterial biofilm growth on said surfaces. Integration of a novel thiazolidinedione derivative into the acrylic emulsion polymers was assessed using Energy Dispersive X-ray Spectrometry analysis and surface topography was visualized and quantified on corrugated cardboard surfaces. Biofilm growth was measured using q-PCR targeting the gene encoding 16s rRNA. Additionally, architectural structure of the biofilm was observed using SEM. The uniform integration of the thiazolidinedione derivative TZD-6 was confirmed, and it was determined via q-PCR to reduce biofilm growth by ~80% on tested surfaces. A novel and effective method for reducing microbial load and preventing contamination on food packaging is thereby proposed.

Mitigation of Biofilm Formation on Corrugated Cardboard Fresh Produce Packaging Surfaces Using a Novel Thiazolidinedione Derivative Integrated in Acrylic Emulsion Polymers.

Science.gov (United States)

Brandwein, Michael; Al-Quntar, Abed; Goldberg, Hila; Mosheyev, Gregory; Goffer, Moshe; Marin-Iniesta, Fulgencio; López-Gómez, Antonio; Steinberg, Doron

2016-01-01

Various surfaces associated with the storage and packing of food are known to harbor distinct bacterial pathogens. Conspicuously absent among the plethora of studies implicating food packaging materials and machinery is the study of corrugated cardboard packaging, the worldwide medium for transporting fresh produce. In this study, we observed the microbial communities of three different store-bought fruits and vegetables, along with their analog cardboard packaging using high throughput sequencing technology. We further developed an anti-biofilm polymer meant to coat corrugated cardboard surfaces and mediate bacterial biofilm growth on said surfaces. Integration of a novel thiazolidinedione derivative into the acrylic emulsion polymers was assessed using Energy Dispersive X-ray Spectrometry (EDS) analysis and surface topography was visualized and quantified on corrugated cardboard surfaces. Biofilm growth was measured using q-PCR targeting the gene encoding 16s rRNA. Additionally, architectural structure of the biofilm was observed using SEM. The uniform integration of the thiazolidinedione derivative TZD-6 was confirmed, and it was determined via q-PCR to reduce biofilm growth by ~80% on tested surfaces. A novel and effective method for reducing microbial load and preventing contamination on food packaging is thereby proposed.

Effects of corrugation shape on frequency band-gaps for longitudinal wave motion in a periodic elastic layer

DEFF Research Database (Denmark)

Sorokin, Vladislav

2016-01-01

The paper concerns determining frequency band-gaps for longitudinal wave motion in a periodic waveguide. The waveguide may be considered either as an elastic layer with variable thickness or as a rod with variable cross section. As a result, widths and locations of all frequency band-gaps are det......The paper concerns determining frequency band-gaps for longitudinal wave motion in a periodic waveguide. The waveguide may be considered either as an elastic layer with variable thickness or as a rod with variable cross section. As a result, widths and locations of all frequency band......, harmonic in the corrugation series. The revealed insights into the mechanism of band-gap formation can be used to predict locations and widths of all frequency band-gaps featured by any corrugation shape. These insights are general and can be valid also for other types of wave motion in periodic structures...

Inkjet printing of UHF antennas on corrugated cardboards for packaging applications

Energy Technology Data Exchange (ETDEWEB)

Sowade, Enrico, E-mail: enrico.sowade@mb.tu-chemnitz.de [Digital Printing and Imaging Technology, Technische Universität Chemnitz, Chemnitz (Germany); Göthel, Frank [Digital Printing and Imaging Technology, Technische Universität Chemnitz, Chemnitz (Germany); Zichner, Ralf [Department Printed Functionalities, Fraunhofer Institute for Electronic Nano Systems (ENAS), Chemnitz (Germany); Baumann, Reinhard R. [Digital Printing and Imaging Technology, Technische Universität Chemnitz, Chemnitz (Germany); Department Printed Functionalities, Fraunhofer Institute for Electronic Nano Systems (ENAS), Chemnitz (Germany)

2015-03-30

Highlights: • Inkjet printing of UHF antennas on cardboard substrates. • Development of primer layer to compensate the absorptiveness of the cardboard and the rough surface. • Manufacturing of UHF antennas in a fully digital manner for packaging applications. - Abstract: In this study, a method based on inkjet printing has been established to develop UHF antennas on a corrugated cardboard for packaging applications. The use of such a standardized, paper-based packaging substrate as material for printing electronics is challenging in terms of its high surface roughness and high ink absorption rate, especially when depositing very thin films with inkjet printing technology. However, we could obtain well-defined silver layers on the cardboard substrates due to a primer layer approach. The primer layer is based on a UV-curable ink formulation and deposited as well as the silver ink with inkjet printing technology. Industrial relevant printheads were chosen for the deposition of the materials. The usage of inkjet printing allows highest flexibility in terms of pattern design. The primer layer was proven to optimize the surface characteristics of the substrate, mainly reducing the surface roughness and water absorptiveness. Thanks to the primer layer approach, ultra-high-frequency (UHF) radio-frequency identification (RFID) antennas were deposited by inkjet printing on the corrugated cardboards. Along with the characterization and interpretation of electrical properties of the established conductive antenna patterns, the performance of the printed antennas were analyzed in detail by measuring the scattering parameter S{sub 11} and the antenna gain.

Experimental evaluation of the performances of cellulosic pads made out of Kraft and NSSC corrugated papers as evaporative media

International Nuclear Information System (INIS)

Barzegar, Mahsa; Layeghi, Mohammad; Ebrahimi, Ghanbar; Hamzeh, Yahya; Khorasani, Manouchehr

2012-01-01

Highlights: ► We experimentally evaluated the performances of cellulosic pads. ► A number of experiments have been done in a wind tunnel. ► The results showed that cooling efficiency improves with decrease of air velocity and flute size. ► Water consumption increases with the increase of air velocity. ► Cooling efficiency of various pads was also compared. - Abstract: The purpose of this study was to evaluate the performances of cellulosic pads made out of Kraft and NSSC corrugated papers in three flute sizes, experimentally. A number of experiments have been done in a wind tunnel in order to evaluate the cooling efficiency and water consumption as a function of air velocity. The tests were carried out at three levels of air velocity (1.8, 2.25, and 2.67 ms −1 ) for three flute sizes of Kraft and NSSC corrugated papers (2.5, 3.5, and 4.5 mm). Analysis of the results indicated that cooling efficiency improves with decrease of air velocity and flute size of corrugated papers; however, water consumption increases with the increase of air velocity. The results were compared with each other and it was shown that the cellulosic pad made out of Kraft paper with 2.5 mm flute size has the highest performance (92%) at 1.8 ms −1 air velocity in comparison with the other cellulosic pads.

Thermo-hydraulic characterization of a self-pumping corrugated wall heat exchanger

International Nuclear Information System (INIS)

Schmidmayer, Kevin; Kumar, Prashant; Lavieille, Pascal; Miscevic, Marc; Topin, Frédéric

2017-01-01

Compactness, efficiency and thermal control of the heat exchanger are of critical significance for many electronic industry applications. In this view, a new concept of heat exchanger at millimeter scale is proposed and numerically studied. It consists in dynamically deforming at least one of its walls by a progressive wave in order to create an active corrugated channel. Systematic studies were performed in single-phase flow on the different deformation parameters that allow obtaining the thermo-hydraulic characteristics of the system. It has been observed the dynamic wall deformation induces a significant pumping effect. Intensification of heat transfer remains very important even for highly degraded waveforms although the pumping efficiency is reduced in this case. The mechanical power applied on the upper wall to deform it dynamically is linked to the wave shape, amplitude, frequency and outlet-inlet pressure difference. The overall performance of the proposed system has been evaluated and compared to existing static channels. The performance of the proposed heat exchanger evolved in two steps for a given wall deformation. It declines slightly up to a critical value of mechanical power applied on the wall. When this critical value is exceeded, it deteriorates significantly, reaching the performance of existing conventional systems. - Highlights: • A new concept of heat exchanger within channel at millimeter scale is proposed. • Upper wall is deformed dynamically by applying external mechanical power. • Pumping effect is observed and is linked to the wave shape, amplitude and frequency. • Efficient proposed system in low Reynolds number range. • Overall performance is significantly high compared to static corrugated and straight channels.

U-rans model for the prediction of the acoustic sound power generated in a whistling corrugated pipe

NARCIS (Netherlands)

Golliard, J.; González Díez, N.; Belfroid, S.P.C.; Nakiboǧlu, G.; Hirschberg, A.

2013-01-01

Corrugated pipes, as used in flexible risers for gas production or in domestic appliances, can whistle when a flow is imposed through the pipe. Nakiboglu et al [1, 2] have developed a method to compute the acoustic source term for axi-symmetric cavities. The method is based on the resolution of

Optimization of a Conical Corrugated Antenna Using Multiobjective Heuristics for Radio-Astronomy Applications

OpenAIRE

López-Ruiz, S.; Sánchez Montero, R.; Tercero-Martínez, F.; López-Espí, P. L.; López-Fernandez, J. A.

2016-01-01

This paper presents the design of a tree sections corrugated horn antenna with a modified linear profile, using NURBS, suitable for radio-astronomy applications. The operating band ranges from 4.5 to 8.8 GHz. The aperture efficiency is higher than 84% and the return losses are greater than 20 dB in the whole bandwidth. The antenna optimization has been carried out with multiobjective versions of an evolutionary algorithm (EA) and a particle swarm optimization (PSO) algorithm. We show that bot...

ΔM/sub j/ transitions in homonuclear molecule scattering off corrugated surfaces. Square and rectangular lattice symmetry and purely repulsive interaction

International Nuclear Information System (INIS)

Proctor, T.R.; Kouri, D.J.; Gerber, R.B.

1984-01-01

In this paper, we present the first formal and computational studies of Δm/sub j/ transitions occurring in homonuclear molecule-corrugated surface collisions. The model potential is a pairwise additive one which correctly incorporates the fact that Δm/sub j/ transitions occur only for corrugated surfaces (provided the quantization axis is chosen to be the average surface normal). The principal results are: (a) Δm/sub j/ transitions are extremely sensitive to lattice symmetry; (b) strong selection rules obtain for specular scattering; (c) the magnitude of Δm/sub j/ -transition probabilities are strongly sensitive to surface corrugation; (d) the Δm/sub j/ transitions depend strongly on diffraction peak; (e) the ratio of molecular length to lattice dimension (r/a) has a strong influence on the magnitude of Δm/sub j/ -transition probabilities [with the probabilities increasing as (r/a) increases]; (f) Δm/sub j/ rainbows are predicted to occur as a function of the (r/a) ratio increases; (g) Δm/sub j/ transitions and the Δm/sub j/ rainbow are expected to accompany Δj-rotational rainbows; (h) such magnetic transition rainbows accompanying Δj rainbows are suggested as an explanation of recent experimental observations of quenching of NO polarization for larger Δj transitions in NO/Ag(111) scattering

Flexible Engineering Structures from the Corrugated Metal Sheets - Comparison of Costs of Solutions used in the Road Building

Science.gov (United States)

Ołdakowska, E.

2017-11-01

The flexible structures from the corrugated metal sheets are used in particular in the road building, especially as passages for animals. Easy and quick assembly, as well as lower realization costs when compared to the traditional solutions increase interest in such structures. Availability and variety of systems allows for searching for solutions which are the best and optimal in the economical range. The article presents the comparison of costs of the basic materials used in various systems of flexible structures from the corrugated metal sheets. In order to determine the costs of the material solutions the data for two systems used in Poland (for construction of the upper passages for animals) since 2008 have been used. The cost estimation for the basic materials required for realization of 1 m2 of the flexible structure from the corrugated steel sheets have been prepared with use of prices obtained directly from the Polish contractors and manufacturers, as well as process included in the quarterly information (Sekocenbud). The difference of prices of materials available on the market allows the investor for selecting the structure depending on the needs and financial possibilities, as well as for achieving some savings. The savings in case of purchasing sheets of identical parameters (thickness, profile characteristics) are from approx. 4% to 8% per 1 m2 of sheet. The connectors in form of bolts M20 cl. 8.8 of various lengths are an expense from 3.00 PLN to 3.50 PLN. Those values may seem low, but taking into consideration amounts connected with construction of many square meters of structure they may become very important factor in the total investment costs.

Using pipe with corrugated walls for a subterahertz free electron laser

Directory of Open Access Journals (Sweden)

Gennady Stupakov

2015-03-01

Full Text Available A metallic pipe with corrugated walls supports propagation of a high-frequency mode that is in resonance with a relativistic beam propagating along the axis of the pipe. This mode can be excited by a beam whose length is a fraction of the wavelength. In this paper, we study another option of excitation of the resonant mode—via the mechanism of the free electron laser instability. This mechanism works if the bunch length is much longer than the wavelength of the radiation and, hence, does not require bunch compression. It provides an alternative to excitation by short bunches that can be realized with relatively low energy and low peak-current electron beams.

Geometrical properties of turbulent premixed flames and other corrugated interfaces

Science.gov (United States)

Thiesset, F.; Maurice, G.; Halter, F.; Mazellier, N.; Chauveau, C.; Gökalp, I.

2016-01-01

This study focuses on the geometrical properties of turbulent flame fronts and other interfaces. Toward that end, we use an original tool based on proper orthogonal decomposition (POD), which is applied to the interface spatial coordinates. The focus is mainly on the degree of roughness of the flame front, which is quantified through the scale dependence of its coverage arclength. POD is first validated by comparing with the caliper technique. Fractal characteristics are extracted in an unambiguous fashion using a parametric expression which appears to be impressively well suited for representing Richardson plots. Then it is shown that, for the range of Reynolds numbers investigated here, the scale-by-scale contribution to the arclength does not comply with scale similarity, irrespectively of the type of similarity which is invoked. The finite ratios between large and small scales, referred to as finite Reynolds number effects, are likely to explain this observation. In this context, the Reynolds number that ought to be achieved for a proper inertial range to be discernible, and for scale similarity to be likely to apply, is calculated. Fractal characteristics of flame folding are compared to available predictions. It is confirmed that the inner cutoff satisfactorily correlates with the Kolmogorov scale while the outer cutoff appears to be proportional to the integral length scale. However, the scaling for the fractal dimension is much less obvious. It is argued that much higher Reynolds numbers have to be reached for drawing firm statements about the evolution (or constancy) of the fractal dimension with respect to flame and flow parameters. Finally, a heuristic phenomenology of corrugated interfaces is highlighted. The degree of generality of the latter phenomenology is confirmed by comparing the folding of different interfaces including a turbulent-nonturbulent interface, a liquid jet destabilized by a surrounding air jet, a cavitating flow, and an isoscalar

Experimental investigation of laminar flow of viscous oil through a circular tube having integral axial corrugation roughness and fitted with twisted tapes with oblique teeth

Science.gov (United States)

Pal, Sagnik; Saha, Sujoy Kumar

2015-08-01

The experimental friction factor and Nusselt number data for laminar flow of viscous oil through a circular duct having integral axial corrugation roughness and fitted with twisted tapes with oblique teeth have been presented. Predictive friction factor and Nusselt number correlations have also been presented. The thermohydraulic performance has been evaluated. The major findings of this experimental investigation are that the twisted tapes with oblique teeth in combination with integral axial corrugation roughness perform significantly better than the individual enhancement technique acting alone for laminar flow through a circular duct up to a certain value of fin parameter.

Asymptotic freeze-out of the perturbations generated inside a corrugated rarefaction wave

International Nuclear Information System (INIS)

Wouchuk, J.G.; Serrano Rodrigo, A.D.

2004-01-01

Based on previous work [J. G. Wouchuk and R. Carretero, Phys. Plasmas 10, 4237 (2003)], the conditions of asymptotic freeze-out of the ripples at the tail of a corrugated rarefaction wave are analyzed. The precise location of the freezing-out regions in the space of preshock parameters is tried, and an efficient algorithm for their determination is given. It is seen that asymptotic freeze-out can only happen for gases that have an isentropic exponent γ cr ≅2.2913hellip. It is shown that the late time freeze-out of the ripple perturbations is correlated to the initial tangential velocity profile (at t=0+) inside the expansion fan

Corrugator Activity Confirms Immediate Negative Affect in Surprise

Directory of Open Access Journals (Sweden)

Sascha eTopolinski

2015-02-01

Full Text Available The emotion of surprise entails a complex of immediate responses, such as cognitive interruption, attention allocation to, and more systematic processing of the surprising stimulus. All these processes serve the ultimate function to increase processing depth and thus cognitively master the surprising stimulus. The present account introduces phasic negative affect as the underlying mechanism responsible for these consequences. Surprising stimuli are schema-discrepant and thus entail cognitive disfluency, which elicits immediate negative affect. This affect in turn works like a phasic cognitive tuning switching the current processing mode from more automatic and heuristic to more systematic and reflective processing. Directly testing the initial elicitation of negative affect by suprising events, the present experiment presented high and low surprising neutral trivia statements to N = 28 participants while assessing their spontaneous facial expressions via facial electromyography. High compared to low suprising trivia elicited higher corrugator activity, indicative of negative affect and mental effort, while leaving zygomaticus (positive affect and frontalis (cultural surprise expression activity unaffected. Future research shall investigate the mediating role of negative affect in eliciting surprise-related outcomes.

Influence of the interface corrugation on the subband dispersions and the optical properties of (113)-oriented GaAs/AlAs superlattices

DEFF Research Database (Denmark)

Langbein, Wolfgang Werner; Lüerssen, D.; Kalt, H.

1996-01-01

We report on the influence of the interface corrugation in (113)-grown GaAs/AlAs superlattices on their band-edge optical properties both in theory and experiment. We calculate the subband dispersions and the optical anisotropies in a multiband k . p formalism. The dominating contribution...... to the optical anisotropies is found to be due to the intrinsic properties of the valence-band structure. The corrugation modifies the density of states only slightly, giving no evidence of a quantum-win behavior. By comparing the calculation with the experimental optical anisotropy, we can estimate...... of the localized type-I states at the band-edge show an enhanced optical anisotropy in comparison to the luminescence of the extended states, revealing the anisotropic nature of their localization sites. In type-II samples, deeply localized, isolated type-I states (Gamma quantum boxes) dominate the luminescence...

Theory of the corrugation instability of a piston-driven shock wave.

Science.gov (United States)

Bates, J W

2015-01-01

We analyze the two-dimensional stability of a shock wave driven by a steadily moving corrugated piston in an inviscid fluid with an arbitrary equation of state. For h≤-1 or h>h(c), where h is the D'yakov parameter and h(c) is the Kontorovich limit, we find that small perturbations on the shock front are unstable and grow--at first quadratically and later linearly--with time. Such instabilities are associated with nonequilibrium fluid states and imply a nonunique solution to the hydrodynamic equations. The above criteria are consistent with instability limits observed in shock-tube experiments involving ionizing and dissociating gases and may have important implications for driven shocks in laser-fusion, astrophysical, and/or detonation studies.

Hierarchical synthesis of corrugated photocatalytic TiO{sub 2} microsphere architectures on natural pollen surfaces

Energy Technology Data Exchange (ETDEWEB)

Erdogan, Deniz Altunoz; Ozensoy, Emrah, E-mail: ozensoy@fen.bilkent.edu.tr

2017-05-01

Highlights: • Biotemplate-based photocatalytic material was synthesized in the form of corrugated TiO{sub 2} microspheres. • Characterization of photocatalysts as a function of temperature. • Photocatalytic activities studied in the gas and solution phases. - Abstract: Biomaterials are challenging, yet vastly promising templates for engineering unusual inorganic materials with unprecedented surface and structural properties. In the current work, a novel biotemplate-based photocatalytic material was synthesized in the form of corrugated TiO{sub 2} microspheres by utilizing a sol-gel methodology where Ambrosia trifida (Ab, Giant ragweed) pollen was exploited as the initial biological support surface. Hierarchically synthesized TiO{sub 2} microspheres were structurally characterized in detail via SEM-EDX, Raman spectroscopy, XRD and BET techniques in order to shed light on the surface chemistry, crystal structure, chemical composition and morphology of these novel material architectures. Photocatalytic functionality of the synthesized materials was demonstrated both in gas phase as well as in liquid phase. Along these lines, air and water purification capabilities of the synthesized TiO{sub 2} microspheres were established by performing photocatalytic oxidative NOx(g) storage and Rhodamine B(aq) degradation experiments; respectively. The synthetic approach presented herein offers new opportunities to design and create sophisticated functional materials that can be used in micro reactor systems, adsorbents, drug delivery systems, catalytic processes, and sensor technologies.

Local study of flow and low Reynolds thermal-hydraulic performance of a corrugated plane duct: application to plate heat exchangers

International Nuclear Information System (INIS)

Hugonnot, Patrick

1989-01-01

This research thesis addresses the local study of a flow in a corrugated plane duct by using experimental and numerical approaches on the one hand, and the experimental determination of thermal-hydraulic performance at low Reynolds number of different plate heat exchanger ducts on the other hand. Experimental visualisations of the local flow allowed regime transitions in 2D and 3D geometries to be determined. As far as the 2D duct is concerned, a wave profile optimisation is proposed, and the numerical study performed by using the TRIO software is in good agreement with experimental results. The optimised duct configuration can thus be envisaged for an industrial development. The determination of the friction coefficient and of the global heat exchange coefficient of different corrugated ducts allows plate exchangers to be sized on a wide range of Reynolds numbers. The respective influences of natural convection and of fluid thermal dependency on heat exchange have been studied [fr

Parametric Study on the Thermal Performance and Optimal Design Elements of Solar Air Heater Enhanced with Jet Impingement on a Corrugated Absorber Plate

Directory of Open Access Journals (Sweden)

Alsanossi M. Aboghrara

2018-01-01

Full Text Available Previous works revealed that cross-corrugated absorber plate design and jet impingement on a flat absorber plate resulted in a significant increase in the performance of a solar air heater (SAH. Involving these two designs into one continuous design to improve the SAH performance remains absent in the literature. This study aimed to evaluate the achieved enhancement on performance parameters of a SAH with jet impingement on a corrugated absorber plate. An energy balance model was developed to compare the performance parameters of the proposed SAH with the other two SAHs. At a clear sky day and a mass flow rate of 0.04 kg/s, the hourly results revealed that the max fluid outlet temperatures for the proposed SAH, jet-to-flat plate SAH, and cross-corrugated plate SAH are 321, 317, and 313 K, respectively; the max absorber plate temperatures are 323.5, 326.5, and 328 K, respectively; the maximum temperature differences between the absorber plate and fluid outlet are ~3, 9, and 15 K, respectively; the max efficiencies are 65.7, 64.8, and 60%, respectively. Statistical t-test results confirmed significant differences between the mean efficiency of the proposed SAH and SAH with jet-to-flat plate. Hence, the proposed design is considered superior in improving the performance parameters of SAH compared to other designs.

Dynamical back-action at 5.5 GHz in a corrugated optomechanical beam

Energy Technology Data Exchange (ETDEWEB)

Navarro-Urrios, D., E-mail: daniel.navarrourrios@nano.cnr.it [Catalan Institute of Nanoscience and Nanotechnology, Campus UAB, Edifici ICN2, 08193 Bellaterra (Spain); NEST, Istituto Nanoscienze – CNR and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa, I-56127 (Italy); Gomis-Bresco, J.; Alzina, F. [Catalan Institute of Nanoscience and Nanotechnology, Campus UAB, Edifici ICN2, 08193 Bellaterra (Spain); El-Jallal, S. [IEMN, Universite de Lille 1, Villeneuve d’Ascq (France); PRILM, Université Moulay Ismail, Faculté des sciences, Meknès (Morocco); Oudich, M.; Pennec, Y.; Djafari-Rouhani, B. [IEMN, Universite de Lille 1, Villeneuve d’Ascq (France); Pitanti, A. [NEST, Istituto Nanoscienze – CNR and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa, I-56127 (Italy); Capuj, N. [Depto. Física, Universidad de la Laguna, 38206 (Spain); Tredicucci, A. [NEST, Istituto Nanoscienze – CNR and Scuola Normale Superiore, Piazza San Silvestro 12, Pisa, I-56127 (Italy); Dipartimento di Fisica, Universita di Pisa, Largo Pontecorvo 3, I-56127 Pisa (Italy); Griol, A.; Martínez, A. [Nanophotonics Technology Center, Universitat Politècnica de València, Valencia (Spain); Sotomayor Torres, C. M. [Catalan Institute of Nanoscience and Nanotechnology, Campus UAB, Edifici ICN2, 08193 Bellaterra (Spain); Catalan Institution for Research and Advanced Studies (ICREA), 08010 Barcelona (Spain)

2014-12-15

We report on the optomechanical properties of a breathing mechanical mode oscillating at 5.5 GHz in a 1D corrugated Si nanobeam. This mode has an experimental single-particle optomechanical coupling rate of |g{sub o,OM}| = 1.8 MHz (|g{sub o,OM}|/2π = 0.3 MHz) and shows strong dynamical back-action effects at room temperature. The geometrical flexibility of the unit-cell would lend itself to further engineering of the cavity region to localize the mode within the full phononic band-gap present at 4 GHz while keeping high g{sub o,OM} values. This would lead to longer lifetimes at cryogenic temperatures, due to the suppression of acoustic leakage.

ANALYSIS OF LOGISTICS AND SUPPLY CHAIN MANAGEMENT AGILITY IN CORRUGATED BOX INDUSTRY

Directory of Open Access Journals (Sweden)

Yosef Daryanto

2016-04-01

Full Text Available Several analyses were performed in this case study including the analysis of the business environments and the current supply chain system, which than followed by measurement and comparison of supply chain agility performance indicator. As corrugated box industry work in make/engineer to order system and by considering their competitive situation and uncertain business environment it was concluded that they need agility in their supply chain. The main problem was the unbalance power position with paper supplier that resulting low inbound inventory turns. Focusing on this weakness, two solutions were proposed; those are building higher collaboration with paper suppliers and performing better inventory management by set different inventory control and policy for each inventory class

Analytical and Numerical Study of Foam-Filled Corrugated Core Sandwich Panels under Low Velocity Impact

Directory of Open Access Journals (Sweden)

Mohammad Nouri Damghani

2016-05-01

Full Text Available Analytical and finite element simulations are used to predict the effect of core density on the energy absorption of composite sandwich panels under low-velocity impact. The composite sandwich panel contains two facesheets and a foam-filled corrugated core. Analytical model is defined as a two degree-of-freedom system based on equivalent mass, spring, and dashpot to predict the local and global deformation response of a simply supported panel. The results signify a good agreement between analytical and numerical predictions.

Optimization of a Conical Corrugated Antenna Using Multiobjective Heuristics for Radio-Astronomy Applications

Directory of Open Access Journals (Sweden)

S. López-Ruiz

2016-01-01

Full Text Available This paper presents the design of a tree sections corrugated horn antenna with a modified linear profile, using NURBS, suitable for radio-astronomy applications. The operating band ranges from 4.5 to 8.8 GHz. The aperture efficiency is higher than 84% and the return losses are greater than 20 dB in the whole bandwidth. The antenna optimization has been carried out with multiobjective versions of an evolutionary algorithm (EA and a particle swarm optimization (PSO algorithm. We show that both techniques provide good antenna design, but the experience carried out shows that the results of the evolutionary algorithm outperform the particle swarm results.

Long-Term Performance of Primary and Secondary Electroactive Biofilms Using Layered Corrugated Carbon Electrodes

International Nuclear Information System (INIS)

Baudler, André; Riedl, Sebastian; Schröder, Uwe

2014-01-01

The performance of primary and secondary electroactive biofilms grown on layered corrugated carbon (LCC) electrodes was studied over a period of several months. With an average projected current density of 6.7 mA cm −2 , the studied secondary electroactive biofilms outperformed the primary biofilms (3.0 mA cm −2 ) over the entire experimental period. At the same time, both, primary and secondary biofilms, exhibited a constant Coulomb efficiency of about 89%. The study further illustrates that three-dimensional electrodes such as LCC allow a sustained long-term performance without significant decrease in electrode performance.

Long-Term Performance of Primary and Secondary Electroactive Biofilms Using Layered Corrugated Carbon Electrodes

Energy Technology Data Exchange (ETDEWEB)

Baudler, André; Riedl, Sebastian; Schröder, Uwe, E-mail: uwe.schroeder@tu-bs.de [Institute of Environmental and Sustainable Chemistry, Technische Universität Braunschweig, Braunschweig (Germany)

2014-07-30

The performance of primary and secondary electroactive biofilms grown on layered corrugated carbon (LCC) electrodes was studied over a period of several months. With an average projected current density of 6.7 mA cm{sup −2}, the studied secondary electroactive biofilms outperformed the primary biofilms (3.0 mA cm{sup −2}) over the entire experimental period. At the same time, both, primary and secondary biofilms, exhibited a constant Coulomb efficiency of about 89%. The study further illustrates that three-dimensional electrodes such as LCC allow a sustained long-term performance without significant decrease in electrode performance.

Particular treatments in Eddy current technique. Application to the control of corrugated tubes

International Nuclear Information System (INIS)

1982-11-01

When the testing of a given product shows that, owing to a particular shape of this product or to its environment, disturbing effects can hide the presence of harmful defects, use must be made of testing artifices or particular treatments enabling an efficient examination to be made. On this score, many eddy current problems are solved by means of the following processes: - use of specific sensors adapted to the geometry of the product, - spectral analysis of the analog results of analyses, - combination of the results of analyses obtained simultaneously at different frequencies (multifrequency techniques). An example of an application is given for corrugated tubes achieved by hollow and helical milling of smooth tubes [fr

Numerical simulation study of gas-liquid reactive mass transfer along corrugated sheets with interface tracking

International Nuclear Information System (INIS)

Haroun, Y.

2008-11-01

This work is done within the framework of gas treatment and CO 2 capture process development. The main objective of the present work is to fill the gap between classical experiments and industrial conditions by the use of Computational Fluid Dynamics (CFD). The physical problem considered corresponds to the liquid film flow down a corrugate surface under gravity in present of a gas phase. The chemical species in the gas phase absorb in the liquid phase and react. Numerical calculations are carried out in order to determine the impact of physical and geometrical properties on reactive mass transfer in industrial operating conditions. (author)

New insights into the short pitch corrugation development enigma based on 3D-FE dynamic vehicle-track coupled modelling in frictional rolling contact

NARCIS (Netherlands)

Li, S.; Li, Z.; Nunez Vicencio, Alfredo; Dollevoet, R.P.B.J.

2017-01-01

A three-dimensional (3D) finite element (FE) dynamic frictional rolling contact model is presented for the study of short pitch corrugation that considers direct and instantaneous coupling between the contact mechanics and the structural dynamics in a vehicle-track system. In this study, we examine

Distributed feedback interband cascade lasers with top grating and corrugated sidewalls

Energy Technology Data Exchange (ETDEWEB)

Xie, Feng [Thorlabs Quantum Electronics, 10335 Guilford Rd, Jessup, Maryland 20794, USA; Stocker, Michael [Thorlabs Quantum Electronics, 10335 Guilford Rd, Jessup, Maryland 20794, USA; Pham, John [Thorlabs Quantum Electronics, 10335 Guilford Rd, Jessup, Maryland 20794, USA; Towner, Frederick [Thorlabs Quantum Electronics, 10335 Guilford Rd, Jessup, Maryland 20794, USA; Shen, Kun [Thorlabs Quantum Electronics, 10335 Guilford Rd, Jessup, Maryland 20794, USA; Wang, Jie [Center for Nanoscale Materials, Argonne National Laboratory, 9700 S. Cass Avenue, Lemont, Illinois 60439, USA; Lascola, Kevin [Thorlabs Quantum Electronics, 10335 Guilford Rd, Jessup, Maryland 20794, USA

2018-03-26

Distributed feedback (DFB) interband cascade lasers (ICLs) with a 1st order top surface grating were designed and fabricated. Partially corrugated sidewalls were implemented to suppress high order lateral modes. The DFB ICLs have 4 mm long and 4.5 mu m wide ridge waveguides and are mounted epi-up on AlN submounts. We demonstrated a continuous-wave (CW) DFB ICL, from a first wafer which has a large detuning of the gain peak from the DFB wavelength, with a side mode suppression ratio of 30 dB. With proper matching of grating feedback and the gain peak wavelength for the second wafer, a DFB ICL was demonstrated with a maximum CW output power and a maximum wall plug efficiency reaching 42 mW and 2%, respectively, at 25 degrees C. The lasing wavelengths of both lasers are around 3.3 mu m at 25 degrees C. Published by AIP Publishing.

Monotron and azimuthally corrugated: application to the high power microwaves generation; Monotron e cavidades azimutalmente corrugadas: aplicacao a geracao de microondas de alta potencia

Energy Technology Data Exchange (ETDEWEB)

Castro, Pedro Jose de

2003-07-01

The present document reports the activity of construction and initial operation of 6.7 GHz operation for high power microwave generation, the study on cylindrical resonators with azimuthally corrugated cross section, the determination of electrical conductivity of metallic materials and development of dielectric resonators for telecommunication applications.

Fabrication of 20 nm half-pitch gratings by corrugation-directed self-assembly

International Nuclear Information System (INIS)

Kim, Ho-Cheol; Rettner, Charles T; Sundstroem, Linnea

2008-01-01

The evolution of the scaling of modern semiconductor devices is governed by the ability to create scalable high-resolution patterns on substrates. Since it is becoming increasingly difficult and expensive to extend to smaller dimensions using optical lithography, there is a great deal of interest in alternative patterning methods. The self-assembly of block copolymers in thin films, which provides periodic patterns of 10-50 nm length scales, has been recognized as a promising candidate for such patterning. To be practical, however, this approach must provide control over the orientation and lateral placement of the microdomains. We report here our discovery of the controlled alignment of the lamellar microdomains of a block copolymer containing hybrid material using topographic pre-patterns on substrates. We find that this hybrid material forms lamellae with a half-pitch of approximately 20 nm perpendicular to the lines of a surface corrugation

Three dimensional corrugated organic photovoltaics for building integration; improving the efficiency, oblique angle and diffuse performance of solar cells

OpenAIRE

Kettle, Jeff; Bristow, Noel; Sweet, Tracy K. N.; Jenkins, Nick; Benatto, Gisele Alves dos Reis; Jørgensen, Mikkel; Krebs, Frederik C

2015-01-01

The lamination of OPV modules to corrugated roof cladding has been undertaken. The 3-dimensional form of the cladding provides three advantages for outdoor OPV deployment; firstly the ‘footprint’ of the solar cell is reduced, which leads to B10% improved power conversion (PCE) efficiency per unit area. Secondly, the oblique angle performance is enhanced, leading to increased output in the early morning and evening. Indoor characterisation showed a 9-fold enhancement in efficiency was obtainab...

Evaluation of Fatigue Strength Improvement by CFRP Laminates and Shot Peening onto the Tension Flanges Joining Corrugated SteelWebs

Directory of Open Access Journals (Sweden)

Zhi-Yu Wang

2015-08-01

Full Text Available Corrugated steel web with inherent high out-of-plane stiffness has a promising application in configuring large span highway bridge girders. Due to the irregularity of the configuration details, the local stress concentration poses a major fatigue problem for the welded flange plates of high strength low alloy structural steels. In this work, the methods of applying CFRP laminate and shot peening onto the surfaces of the tension flanges were employed with the purpose of improving the fatigue strength of such configuration details. The effectiveness of this method in the improvement of fatigue strength has been examined experimentally. Test results show that the shot peening significantly increases hardness and roughness in contrast to these without treatment. Also, it has beneficial effects on the fatigue strength enhancement when compared against the test data of the joints with CFRP strengthening. The stiffness degradation during the loading progress is compared with each treatment. Incorporating the stress acting on the constituent parts of the CFRP laminates, a discussion is made regarding the mechanism of the retrofit and related influencing factors such as corrosion and economic cost. This work could enhance the understanding of the CFRP and shot peening in repairing such welded details and shed light on the reinforcement design of welded joints between corrugated steel webs and flange plates.

Corrugated Quantum Well Infrared Photodetector Focal Plane Array Test Results

Science.gov (United States)

Goldberg, A.; Choi, K. K.; Das, N. C.; La, A.; Jhabvala, M.

1999-01-01

The corrugated quantum-well infrared photodetector (C-QWIP) uses total internal reflection to couple normal incident light into the optically active quantum wells. The coupling efficiency has been shown to be relatively independent of the pixel size and wavelength thus making the C-QWIP a candidate for detectors over the entire infrared spectrum. The broadband coupling efficiency of the C-QWIP makes it an ideal candidate for multiwavelength detectors. We fabricated and tested C-QWIP focal plane arrays (FPAs) with cutoff wavelengths of 11.2 and 16.2 micrometers. Each FPA has 256 x 256 pixels that are bump-bonded to a direct injection readout circuit. Both FPAs provided infrared imagery with good aesthetic attributes. For the 11.2-micrometers FPA, background-limited performance (BLIP) was observed at 60 K with f/3 optics. For the 16.2-micrometers FPA, BLIP was observed at 38 K. Besides the reduction of dark current in C-QWIP structures, the measured internal quantum efficiency (eta) remains to be high. The values for responsivity and quantum efficiency obtained from the FPA results agree well with those measured for single devices.

Reflection and refraction of elastic waves at a corrugated interface in a bi-material transversely isotropic full-space

International Nuclear Information System (INIS)

Shad-Manamen, N.; Eskandari-Ghadi, M.

2008-01-01

The existing theory for wave propagation through a soil layer are not compatible with the real soil layers because in the theory the layers are flat and the sub-layers are parallel, while in real the soil layers are not flat and they may not be parallel. Thus, wave propagations through a corrugated interface are so important. In this paper, a two dimensional SH-wave propagation through a corrugated interface between two linear transversely isotropic half-spaces is assessed. In order to do this, Lord Rayleigh's method is accepted to express the non-flat surface by a Fourier series. In this way, the amplitude of the reflected and transmitted waves is analytically determined in terms of the incident SH-wave amplitude. It is shown that except for the regular reflected and refracted waves, some irregular reflected and refracted waves are exist, and the amplitudes of these waves vary in terms of the angle and frequency of incident wave, equation of surface, and the material properties of the domains. The numerical computations for some cases of different amplitude/wave-length ratio of the interface are done. This work is an extension of Asano's paper (1960) for a more complicated interface, where more non-zero coefficients are considered in expressing the equation of surface in the form of Fourier series. The analytical results for some simpler case of isotropic domain are collapsed on Asano's results (1960). In addition, the numerical evaluation is in good agreement with Asano's.

Material selection for elastic energy absorption in origami-inspired compliant corrugations

International Nuclear Information System (INIS)

Tolman, Sean S; Delimont, Isaac L; Howell, Larry L; Fullwood, David T

2014-01-01

Elastic absorption of kinetic energy and distribution of impact forces are required in many applications. Recent attention to the potential for using origami in engineering may provide new methods for energy absorption and force distribution. A three-stage strategy is presented for selecting materials for such origami-inspired designs that can deform to achieve a desired motion without yielding, absorb elastic strain energy, and be lightweight or cost effective. Two material indices are derived to meet these requirements based on compliant mechanism theory. Finite element analysis is used to investigate the effects of the material stiffness in the Miura-ori tessellation on its energy absorption and force distribution characteristics compared with a triangular wave corrugation. An example is presented of how the method can be used to select a material for a general energy absorption application of the Miura-ori. Whereas the focus of this study is the Miura-ori tessellation, the methods developed can be applied to other tessellated patterns used in energy absorbing or force distribution applications. (paper)

Mitigation of biofilm formation on corrugated cardboard fresh produce packaging surfaces using a novel thiazolidinedione derivative integrated in acrylic emulsion polymers

OpenAIRE

Michael eBrandwein; Abed eAl-Quntar; Abed eAl-Quntar; Hila eGoldberg; Gregory eMosheyev; Moshe eGoffer; Fulgencio eMarin-Iniesta; Antonio eLopez-Gomez; Doron eSteinberg

2016-01-01

Various surfaces associated with the storage and packing of food are known to harbor distinct bacterial pathogens. Conspicuously absent among the plethora of studies implicating food packaging materials and machinery is the study of corrugated cardboard packaging, the worldwide medium for transporting fresh produce. In this study, we observed the microbial communities of three different store-bought fruits and vegetables, along with their analogue cardboard packaging using high throughput seq...

Mitigation of Biofilm Formation on Corrugated Cardboard Fresh Produce Packaging Surfaces Using a Novel Thiazolidinedione Derivative Integrated in Acrylic Emulsion Polymers

OpenAIRE

Brandwein, Michael; Al-Quntar, Abed; Goldberg, Hila; Mosheyev, Gregory; Goffer, Moshe; Marin-Iniesta, Fulgencio; L?pez-G?mez, Antonio; Steinberg, Doron

2016-01-01

Various surfaces associated with the storage and packing of food are known to harbor distinct bacterial pathogens. Conspicuously absent among the plethora of studies implicating food packaging materials and machinery is the study of corrugated cardboard packaging, the worldwide medium for transporting fresh produce. In this study, we observed the microbial communities of three different store-bought fruits and vegetables, along with their analog cardboard packaging using high throughput seque...

The peeling behaviour of a graphene sheet on a nano-scale corrugated surface

International Nuclear Information System (INIS)

Chen, Hao; Chen, Shaohua

2013-01-01

The peeling process and average peeling force of a graphene (GE) sheet on a corrugated surface are investigated using molecular dynamics simulation. It is found that the peeling behaviour varies with the substrate surface roughness and the peeling angle. Three kinds of typically peeling behaviours include (a) GE sheet directly passing the valley of the substrate roughness; (b) bouncing off from the substrate; and (c) continuously peeling off similarly to that on a flat substrate. As a result, the average peeling force is strongly dependent of the peeling behaviours. Furthermore, some interesting phenomena are caught, such as partial detaching and partial sliding of GE sheet in the valley of the substrate roughness, which are mainly due to the effects of pre-tension in GE sheet and the reduction of friction resistance. The results in this paper should be useful for the design of nano-film/substrate systems. (paper)

Post-Hartree-Fock studies of the He/Mg(0001) interaction: Anti-corrugation, screening, and pairwise additivity

Energy Technology Data Exchange (ETDEWEB)

Lara-Castells, María Pilar de, E-mail: Pilar.deLara.Castells@csic.es [Instituto de Física Fundamental (CSIC), Serrano 123, E-28006 Madrid (Spain); Fernández-Perea, Ricardo [Instituto de Estructura de la Materia (CSIC), Serrano 123, E-28006 Madrid (Spain); Madzharova, Fani; Voloshina, Elena, E-mail: elena.voloshina@hu-berlin.de [Humboldt-Universität zu Berlin, Institut für Chemie, Unter den Linden 6, 10099 Berlin (Germany)

2016-06-28

The adsorption of noble gases on metallic surfaces represents a paradigmatic case of van-der-Waals (vdW) interaction due to the role of screening effects on the corrugation of the interaction potential [J. L. F. Da Silva et al., Phys. Rev. Lett. 90, 066104 (2003)]. The extremely small adsorption energy of He atoms on the Mg(0001) surface (below 3 meV) and the delocalized nature and mobility of the surface electrons make the He/Mg(0001) system particularly challenging, even for state-of-the-art vdW-corrected density functional-based (vdW-DFT) approaches [M. P. de Lara-Castells et al., J. Chem. Phys. 143, 194701 (2015)]. In this work, we meet this challenge by applying two different procedures. First, the dispersion-corrected second-order Möller-Plesset perturbation theory (MP2C) approach is adopted, using bare metal clusters of increasing size. Second, the method of increments [H. Stoll, J. Chem. Phys. 97, 8449 (1992)] is applied at coupled cluster singles and doubles and perturbative triples level, using embedded cluster models of the metal surface. Both approaches provide clear evidences of the anti-corrugation of the interaction potential: the He atom prefers on-top sites, instead of the expected hollow sites. This is interpreted as a signature of the screening of the He atom by the metal for the on-top configuration. The strong screening in the metal is clearly reflected in the relative contribution of successively deeper surface layers to the main dispersion contribution. Aimed to assist future dynamical simulations, a pairwise potential model for the He/surface interaction as a sum of effective He–Mg pair potentials is also presented, as an improvement of the approximation using isolated He–Mg pairs.

Methods to introduce sub-micrometer, symmetry-breaking surface corrugation to silicon substrates to increase light trapping

Energy Technology Data Exchange (ETDEWEB)

Han, Sang Eon; Hoard, Brittany R.; Han, Sang M.; Ghosh, Swapnadip

2018-04-10

Provided is a method for fabricating a nanopatterned surface. The method includes forming a mask on a substrate, patterning the substrate to include a plurality of symmetry-breaking surface corrugations, and removing the mask. The mask includes a pattern defined by mask material portions that cover first surface portions of the substrate and a plurality of mask space portions that expose second surface portions of the substrate, wherein the plurality of mask space portions are arranged in a lattice arrangement having a row and column, and the row is not oriented parallel to a [110] direction of the substrate. The patterning the substrate includes anisotropically removing portions of the substrate exposed by the plurality of spaces.

Quasi-phase-matched acceleration of electrons in a corrugated plasma channel

Directory of Open Access Journals (Sweden)

S. J. Yoon

2012-08-01

Full Text Available A laser pulse propagating in a corrugated plasma channel is composed of spatial harmonics whose phase velocities can be subluminal. The phase velocity of a spatial harmonic can be matched to the speed of a relativistic electron resulting in direct acceleration by the guided laser field in a plasma waveguide and linear energy gain over the interaction length. Here we examine the fully self-consistent interaction of the laser pulse and electron beam using particle-in-cell (PIC simulations. For low electron beam densities, we find that the ponderomotive force of the laser pulse pushes plasma channel electrons towards the propagation axis, which deflects the beam electrons. When the beam density is high, the space charge force of the beam drives the channel electrons off axis, providing collimation of the beam. In addition, we consider a ramped density profile for lowering the threshold energy for trapping in a subluminal spatial harmonic. By using a density ramp, the trapping energy for a normalized vector potential of a_{0}=0.1 is reduced from a relativistic factor γ_{0}=170 to γ_{0}=20.

Broadband Amplification of Low-Terahertz Signals Using Axis-Encircling Electrons in a Helically Corrugated Interaction Region

Science.gov (United States)

He, W.; Donaldson, C. R.; Zhang, L.; Ronald, K.; Phelps, A. D. R.; Cross, A. W.

2017-11-01

Experimental results are presented of a broadband, high power, gyrotron traveling wave amplifier (gyro-TWA) operating in the (75-110)-GHz frequency band and based on a helically corrugated interaction region. The second harmonic cyclotron mode of a 55-keV, 1.5-A, axis-encircling electron beam is used to resonantly interact with a traveling TE21 -like eigenwave achieving broadband amplification. The gyro-TWA demonstrates a 3-dB gain bandwidth of at least 5.5 GHz in the experimental measurement with 9 GHz predicted for a wideband drive source with a measured unsaturated output power of 3.4 kW and gain of 36-38 dB. The approach may allow a gyro-TWA to operate at 1 THz.

Flows of Newtonian and Power-Law Fluids in Symmetrically Corrugated Cappilary Fissures and Tubes

Science.gov (United States)

Walicka, A.

2018-02-01

In this paper, an analytical method for deriving the relationships between the pressure drop and the volumetric flow rate in laminar flow regimes of Newtonian and power-law fluids through symmetrically corrugated capillary fissures and tubes is presented. This method, which is general with regard to fluid and capillary shape, can also be used as a foundation for different fluids, fissures and tubes. It can also be a good base for numerical integration when analytical expressions are hard to obtain due to mathematical complexities. Five converging-diverging or diverging-converging geometrics, viz. wedge and cone, parabolic, hyperbolic, hyperbolic cosine and cosine curve, are used as examples to illustrate the application of this method. For the wedge and cone geometry the present results for the power-law fluid were compared with the results obtained by another method; this comparison indicates a good compatibility between both the results.

Flows of Newtonian and Power-Law Fluids in Symmetrically Corrugated Cappilary Fissures and Tubes

Directory of Open Access Journals (Sweden)

Walicka A.

2018-02-01

Full Text Available In this paper, an analytical method for deriving the relationships between the pressure drop and the volumetric flow rate in laminar flow regimes of Newtonian and power-law fluids through symmetrically corrugated capillary fissures and tubes is presented. This method, which is general with regard to fluid and capillary shape, can also be used as a foundation for different fluids, fissures and tubes. It can also be a good base for numerical integration when analytical expressions are hard to obtain due to mathematical complexities. Five converging-diverging or diverging-converging geometrics, viz. wedge and cone, parabolic, hyperbolic, hyperbolic cosine and cosine curve, are used as examples to illustrate the application of this method. For the wedge and cone geometry the present results for the power-law fluid were compared with the results obtained by another method; this comparison indicates a good compatibility between both the results.

A Comparative Study of Dispersion Characteristics Determination of a Trapezoidally Corrugated Slow Wave Structure Using Different Techniques

International Nuclear Information System (INIS)

Saber, Md. Ghulam; Sagor, Rakibul Hasan; Amin, Md. Ruhul

2016-01-01

The linear dispersion relation of a trapezoidally corrugated slow wave structure (TCSWS) is analyzed and presented. The size parameters of the TCSWS are chosen in such a way that they operate in the x-band frequency range. The dispersion relation is solved by utilizing the Rayleigh–Fourier method by expressing the radial function in terms of the Fourier series. A highly accurate synthetic technique is also applied to determine the complete dispersion characteristics from experimentally measured resonances (cold test). Periodic structures resonate at specific frequencies when the terminals are shorted appropriately. The dispersion characteristics obtained from numerical calculation, synthetic technique and cold test are compared, and an excellent agreement is achieved. (paper)

The steady-state tangential contact problem for a falling drop type of contact area on corrugated rail by simplified theory of rolling contact

Science.gov (United States)

Piotrowski, Jerzy

1991-10-01

Investigation of contact mechanical nonlinearities of a mathematical model of corrugation revealed that the typical shape of contact patch resembles a falling drop of water. A contact patch of that shape was approximated with a figure composed of two parts of ellipses with different eccentricities. The contact pressure distribution was assumed as a smoothing ensemble of two paraboloidal distributions. The description of a general case of double half elliptical contact area was given but a special case of double half elliptical contact is more interesting as it possesses some Hertzian properties. It was shown how three geometrical parameters of double half elliptical contact can be chosen when actual, non-Hertzian contact is known. A linear theory was written which indicates that the lateral vibrations of the rail may be excited only due to shape variation on corrugation even if any other cause for these vibrations does not exist. For nonlinear theory a computer program, based on FASTSIM algorithm by Kalker, was written. The aim is to calculate the creep forces and frictional power density distribution over the contact area. Also, a graphic program visualizing the solution was written. Numerical results are not provided; unattended and unsolved problems relevant for this type of contact are listed.

High-power corrugates waveguide components for mm-wave fusion heating systems

International Nuclear Information System (INIS)

Olstad, R.A.; Doane, J.L.; Moeller, C.P.; O'Neill, R.C.; Di Martino, M.

1996-10-01

Considerable progress has been made over the last year in the U.S., Japan, Russia, and Europe in developing high power long pulse gyrotrons for fusion plasma heating and current drive. These advanced gyrotrons typically operate at a frequency in the range 82 GHz to 170 GHz at nearly megawatt power levels for pulse lengths up to 5 s. To take advantage of these new microwave sources for fusion research, new and improved transmission line components are needed to reliably transmit microwave power to plasmas with minimal losses. Over the last year, General Atomics and collaborating companies (Spinner GmbH in Europe and Toshiba Corporation in Japan) have developed a wide variety of new components which meet the demanding power, pulse length, frequency, and vacuum requirements for effective utilization of the new generation of gyrotrons. These components include low-loss straight corrugated waveguides, miter bends, miter bend polarizers, power monitors, waveguide bellows, de breaks, waveguide switches, dummy loads, and distributed windows. These components have been developed with several different waveguide diameters (32, 64, and 89 mm) and frequency ranges (82 GHz to 170 GHz). This paper describes the design requirements of selected components and their calculated and measured performance characteristics

SPREADING OF A FLUID JET ON THE CORRUGATED SURFACE OF THE STRUCTURED PACKING OF WET SCRUBBERS

Directory of Open Access Journals (Sweden)

Gorodilov A.A.

2014-08-01

Full Text Available The new packing for wet scrubbers for cooling exhaust gases of furnaces is presented. Spreading features of the fluid jet on the corrugated surface of the proposed packing have been studied. Flow rate of the liquid flowing through slits to the opposite side of the packing element was determined. Several regimes of a fluid flow on the surface of the proposed structured packing were determined. An optimal range of rational flow rates for more intense cooling of exhaust gases is proposed. It was discovered that the range of optimum flow rates may be extended if the surface of the packing element is pre-wetted. The way of increasing the rate of effective interfacial surface area for gas-liquid contact per unit volume of the packing of the scrubber is presented.

The Fluid-Solid Interaction Dynamics between Underwater Explosion Bubble and Corrugated Sandwich Plate

Directory of Open Access Journals (Sweden)

Hao Wang

2016-01-01

Full Text Available Lightweight sandwich structures with highly porous 2D cores or 3D (three-dimensional periodic cores can effectively withstand underwater explosion load. In most of the previous studies of sandwich structure antiblast dynamics, the underwater explosion (UNDEX bubble phase was neglected. As the UNDEX bubble load is one of the severest damage sources that may lead to structure large plastic deformation and crevasses failure, the failure mechanisms of sandwich structures might not be accurate if only shock wave is considered. In this paper, detailed 3D finite element (FE numerical models of UNDEX bubble-LCSP (lightweight corrugated sandwich plates interaction are developed by using MSC.Dytran. Upon the validated FE model, the bubble shape, impact pressure, and fluid field velocities for different stand-off distances are studied. Based on numerical results, the failure modes of LCSP and the whole damage process are obtained. It is demonstrated that the UNDEX bubble collapse jet local load plays a more significant role than the UNDEX shock wave load especially in near-field underwater explosion.

Effects on the structure of monolayer and submonolayer fluid nitrogen films by the corrugation in the holding potential of nitrogen molecules

DEFF Research Database (Denmark)

Hansen, Flemming Yssing

2001-01-01

of interactions were indicated by the comparison of the calculated and measured isosteric heats of adsorption in fluid films of nitrogen molecules on graphite. The melting temperatures were lowered by 7K and a region of liquid-gas coexistence was observed for films on the smooth graphite surface indicating......The effects of corrugation in the holding potential of nitrogen molecules on the structure of fluid monolayer and submonolayer films of the molecules on a solid substrate was studied using molecular dynamics simulation. Including McLachlan mediation of the intermolecular potential in a model...

Spontaneous acoustic emission of a corrugated shock wave in the presence of a reflecting surface

International Nuclear Information System (INIS)

Wouchuk, J.G.; Lopez Cavada, J.

2004-01-01

An analytic model to study perturbation evolution in the space between a corrugated shock and a piston surface is presented. The conditions for stable oscillation patterns are obtained by looking at the poles of the exact Laplace transform. It is seen that besides the standard D'yakov-Kontorovich (DK) mode of oscillation, the shock surface can exhibit an additional finite set of discrete frequencies, due to the interaction with the piston which reflects sound waves from behind. The additional eigenmodes are excited when the shock is launched at t=0 + . The first eigenmode (the DK mode) is always present, if the Hugoniot curve has the correct slope in the V-p plane. However, the additional frequencies could be excited for strong enough shocks. The predictions of the model are verified for particular cases by studying a van der Waals gas, as in the work of Bates and Montgomery [Phys. Fluids 11, 462 (1999); Phys. Rev. Lett. 84, 1180 (2000)]. Only acoustic emission modes are considered

Alkali reduction of graphene oxide in molten halide salts: production of corrugated graphene derivatives for high-performance supercapacitors.

Science.gov (United States)

Abdelkader, Amr M; Vallés, Cristina; Cooper, Adam J; Kinloch, Ian A; Dryfe, Robert A W

2014-11-25

Herein we present a green and facile approach to the successful reduction of graphene oxide (GO) materials using molten halide flux at 370 °C. GO materials have been synthesized using a modified Hummers method and subsequently reduced for periods of up to 8 h. Reduced GO (rGO) flakes have been characterized using X-ray-diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR), all indicating a significantly reduced amount of oxygen-containing functionalities on the rGO materials. Furthermore, impressive electrical conductivities and electrochemical capacitances have been measured for the rGO flakes, which, along with the morphology determined from scanning electron microscopy, highlight the role of surface corrugation in these rGO materials.

Natural Fiber Reinforced Composites: A Review on Potential for Corrugated Core of Sandwich Structures

Directory of Open Access Journals (Sweden)

Jusoh A.F.

2016-01-01

Full Text Available Natural fibers, characterized by sustainability, have gained a considerable attention in recent years, due to their advantages of environmental acceptability and commercial viability. In this paper, the characterization of natural fibers including the mechanical properties and alkalization of fibers is presented. Most recent study had gone through the mercerization process to improve the toughness of natural fibers; which is a well-known hydrophilic material. Traditional reinforcement method was commonly used to fabricate a natural fiber composite such as hand lay-up and mold press due to its convenience in terms of time and cost. Also, different kind of matrix material used in different kind of natural fibers gave high impact on the tensile and flexural test result. By selecting appropriate chemical treatment, matrix material and fabrication method, the tensile and flexural test gives different results and findings. As most researchers tend to use metals to create corrugated cores for sandwich structure, it is possible to develop this structure using natural fibers such as kenaf, wood dust, and other natural fibers.

Sound Transmission Loss Through a Corrugated-Core Sandwich Panel with Integrated Acoustic Resonators

Science.gov (United States)

Schiller, Noah H.; Allen, Albert R.; Zalewski, Bart F; Beck, Benjamin S.

2014-01-01

The goal of this study is to better understand the effect of structurally integrated resonators on the transmission loss of a sandwich panel. The sandwich panel has facesheets over a corrugated core, which creates long aligned chambers that run parallel to the facesheets. When ports are introduced through the facesheet, the long chambers within the core can be used as low-frequency acoustic resonators. By integrating the resonators within the structure they contribute to the static load bearing capability of the panel while also attenuating noise. An analytical model of a panel with embedded resonators is derived and compared with numerical simulations. Predictions show that acoustic resonators can significantly improve the transmission loss of the sandwich panel around the natural frequency of the resonators. In one configuration with 0.813 m long internal chambers, the diffuse field transmission loss is improved by more than 22 dB around 104 Hz. The benefit is achieved with no added mass or volume relative to the baseline structure. The embedded resonators are effective because they radiate sound out-of-phase with the structure. This results in destructive interference, which leads to less transmitted sound power.

Eficiência térmica de telhas onduladas de fibrocimento aplicadas em abrigos individuais para bezerros expostos ao sol e à sombra Thermal efficiency of fiber cement corrugated sheets applied to individual housing for calves exposed to sun and shade

Directory of Open Access Journals (Sweden)

Juliano Fiorelli

2012-01-01

Full Text Available Este trabalho apresenta um estudo da eficiência térmica de coberturas de bezerreiros individuais expostas ao sol e à sombra, por meio de termografia infravermelha, temperatura interna e índices de conforto térmico. Foram avaliados quatro bezerreiros, três expostos ao sol, a saber: (i cobertos com telhas de fibrocimento sem amianto - pintadas de branco, (ii sem pintura e (iii com sombrite posicionado internamente aos bezerreiros, à distância de 0,10m da face inferior da telha. O quarto bezerreiro foi instalado em área sombreada e coberto com telhas de fibrocimento sem pintura. As coletas de dados foram realizadas durante 21 dias, nos horários das 11h00min, 14h00min e 17h00min. Os resultados mostraram variações significativas na temperatura de superfície das coberturas e nos índices de conforto térmico, entre os tratamentos expostos ao sol e à sombra, para todos os horários avaliados. As imagens termográficas infravermelhas mostraram-se eficientes para melhor compreensão dos processos de transferência de calor da cobertura para o interior das instalações.This research presents a study of roof thermal efficiency in individual housing for calves exposed to sun and shade through infrared thermography, internal temperature and thermal comfort indexes. Four different individual housing for calves covered with asbestos-free fiber-cement corrugated sheets were evaluated. Three of them were directly exposed to the sun: (i corrugated sheets painted white in the external surface, (ii corrugated sheets without painting and (iii with screen shade fabric installed 0.10m under de internal surface of the corrugated sheet. The fourth individual housing was installed in the shade area and covered with unpainted corrugated fiber-cement sheets. The analysis was taken for 21 days at 11h00min, 14h00min and 17h00min. The results indicate significant variations in the roofing surface temperature and thermal comfort indexes among the treatments

Industrial fabrication of an optical security device for document protection using plasmon resonant transmission through a thin corrugated metallic film embedded on a plastic foil

Science.gov (United States)

Sauvage-Vincent, Jean; Jourlin, Yves; Tonchev, Svetlen; Veillas, Colette; Claude, Pedri; Parriaux, Olivier

2012-06-01

Known since a long time in polymer banknotes and presented in the few years in paper banknotes, the principle of windowed documents has been currently extended to ID documents. We present an innovative solution which combines resonant transmission and Zero Order Device technologies and which is dedicated to improve windows in terms of the overt security level. With this R&D program, Hologram Industries targeted to obtain an overt visual security device that should be readily checked in transmission in the same manner as the established paper watermark. The proposed solution is based on the propagation of resonant modes in a thin continuous corrugated metallic layer embedded (encapsulated) between two dielectric layers of near equal refractive index. The mode of most interest is the Long Range Plasmon Mode. The coupling condition to the Long Range Mode is principally related to the corrugation, the metal layer thickness and the index of the two dielectric layers. If the condition of the mode excitation through the grating is fulfilled, a predetermined wavelength will be coupled to the Long Range Plasmon Mode. This mode will propagate at each metal/dielectric interface with a low loss and will concentrate the electric field inside the metal layer. This effect of coupling enables the transmission of a peak at this wavelength through the metallic layer. It defines the so called "extraordinary resonant transmission".

Corrugated paraffin nanocomposite films as large stroke thermal actuators and self-activating thermal interfaces.

Science.gov (United States)

Copic, Davor; Hart, A John

2015-04-22

High performance active materials are of rapidly growing interest for applications including soft robotics, microfluidic systems, and morphing composites. In particular, paraffin wax has been used to actuate miniature pumps, solenoid valves, and composite fibers, yet its deployment is typically limited by the need for external volume constraint. We demonstrate that compact, high-performance paraffin actuators can be made by confining paraffin within vertically aligned carbon nanotube (CNT) films. This large-stroke vertical actuation is enabled by strong capillary interaction between paraffin and CNTs and by engineering the CNT morphology by mechanical compression before capillary-driven infiltration of the molten paraffin. The maximum actuation strain of the corrugated CNT-paraffin films (∼0.02-0.2) is comparable to natural muscle, yet the maximum stress is limited to ∼10 kPa by collapse of the CNT network. We also show how a CNT-paraffin film can serve as a self-activating thermal interface that closes a gap when it is heated. These new CNT-paraffin film actuators could be produced by large-area CNT growth, infiltration, and lamination methods, and are attractive for use in miniature systems due to their self-contained design.

Mechanisms of amplification of ultrashort electromagnetic pulses in gyrotron traveling wave tube with helically corrugated waveguide

International Nuclear Information System (INIS)

Ginzburg, N. S.; Zaslavsky, V. Yu.; Zotova, I. V.; Sergeev, A. S.; Zheleznov, I. V.; Samsonov, S. V.; Mishakin, S. V.

2015-01-01

A time-domain self consistent theory of a gyrotron traveling wave tube with a helically corrugated operating waveguide has been developed. Based on this model, the process of short pulse amplification was studied in regimes of grazing and intersection of the dispersion curves of the electromagnetic wave and the electron beam. In the first case, the possibility of amplification without pulse form distortion was demonstrated for the pulse spectrum width of the order of the gain bandwidth. In the second case, when the electrons' axial velocity was smaller than the wave's group velocity, it was shown that the slippage of the incident signal with respect to the electron beam provides feeding of the signal by “fresh” electrons without initial modulation. As a result, the amplitude of the output pulse can exceed the amplitude of its saturated value for the case of the grazing regime, and, for optimal parameters, the peak output power can be even larger than the kinetic power of the electron beam

Performance of a remote steering antenna for ECRH/ECCS applications using 4-wall corrugated square waveguide

International Nuclear Information System (INIS)

Kasparek, W.; Gantenbein, G.; Plaum, B.; Wacker, R.; Filipovic, E.; Chirkov, A.V.; Denisov, G.G.; Kuzikov, S.V.; Ohkubo, K.; Hollmann, F.; Wagner, D.

2003-01-01

For the upper ECW launcher on ITER, the use of a 'remote steering antenna' based on the imaging properties of rectangular waveguides is planned. To characterise launchers of this type, low-power experiments on a 4-side corrugated square waveguide with a scanning mirror at the input of the waveguide were performed in the frequency range of 140 to 160 GHz. It is shown, that elliptical polarisation needed for ECCD can be transmitted without depolarization. The usable steering range of the antenna is at least -10 angle < φ ≤ + 10 angle. Experiments with the scanning plane in the diagonal of the square waveguide led to a negligible increase the scanning range, and lobes in the upward and downward direction are detected at larger scanning angles. Mitre bends can be integrated into the waveguide without prohibitive extra loss, which is demonstrated by far-field measurements. Detailed calorimetric measurements for this set up confirm this statement for the polarisation perpendicular to the scanning plane, whereas extra loss is measured for the parallel polarisation. Results are discussed and are compared to theory. (authors)

Disinfection of corrugated tubing by ozone and ultrasound in mechanically ventilated tracheostomized patients.

Science.gov (United States)

Lopes, M S; Ferreira, J R F; da Silva, K B; de Oliveira Bacelar Simplício, I; de Lima, C J; Fernandes, A B

2015-08-01

Medical equipment coming into contact with non-intact skin or mucous membranes is classified as semi-critical material. This equipment requires at least high-level disinfection, as the major risk in all invasive procedures is the introduction of pathogenic microbes causing hospital-associated infections. To evaluate the capacity of ozone gas and ultrasound to disinfect semi-critical, thermally sensitive material. Used corrugated tubing from mechanically ventilated tracheostomized patients in the intensive care unit was obtained. Enzymatic detergent was applied for 15min before different disinfection techniques were evaluated as follows: Group A (0.2% peracetic acid); Group B (ultrasound for 60min); Group C (application of ozone gas at a concentration of 33mg/L for 15min); Group D (ultrasound for 30min and ozone for 15min); Group E (ultrasound for 60min and ozone for 15min). Application of ultrasound for 60min reduced the level of microbial contamination by 4 log10, whereas ozone alone and the other two combined techniques (ultrasound and ozone) and the peracetic acid reduced the level of microbial contamination by 5 log10. Ozone was the most advantageous technique taking into consideration processing time, ease of use, effectiveness, and cost. The use of ozone gas to disinfect semi-critical material proved to be technically feasible and extremely promising. Copyright © 2015 The Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Three dimensional corrugated organic photovoltaics for building integration; improving the efficiency, oblique angle and diffuse performance of solar cells

DEFF Research Database (Denmark)

Kettle, Jeff; Bristow, Noel; Sweet, Tracy K. N.

2015-01-01

The lamination of OPV modules to corrugated roof cladding has been undertaken. The 3-dimensional form of the cladding provides three advantages for outdoor OPV deployment; firstly the ‘footprint’ of the solar cell is reduced, which leads to B10% improved power conversion (PCE) efficiency per unit...... area. Secondly, the oblique angle performance is enhanced, leading to increased output in the early morning and evening. Indoor characterisation showed a 9-fold enhancement in efficiency was obtainable, when compared to a flat module. Thirdly, an improvement in performance under diffuse lighting...... conditions was measured, when compared to a flat module. The average daily yield of the 3D module was 17–29% higher than a flat module, with higher relative enhancements observed on cloudier days. Geographically, the 3D module appears to be well-suited to countries with a high latitude, due to the enhanced...

Investigation the Potential Replacement of the Old Corrugated Container (OCC) and Poplar Wood Flour Instead of Wheat Flour such as Urea-formaldehyde Adhesive Filler in the Plywood Industry

OpenAIRE

Kazem D.Hosseini; Meysam Mahdinia; Elham Farhid; Abdollah Elyasi

2012-01-01

Considering the value and importance of wheat flour in our country, replacement of a new type of filler instead of wheat flour in glue combination in plywood industry is necessary. In this study the possibility of using wood flour of poplar and OCC (old corrugated container) fiber as filler in the combination of urea formaldehyde glue has been studied. The plywood was manufactured from Poplar species (in core of plywood) and Hornbeam veneer (in back and face of plywood) on the basis of the st...

Quantitative Photochemical Immobilization of Biomolecules on Planar and Corrugated Substrates: A Versatile Strategy for Creating Functional Biointerfaces

Science.gov (United States)

Martin, Teresa A.; Herman, Christine T.; Limpoco, Francis T.; Michael, Madeline C.; Potts, Gregory K.; Bailey, Ryan C.

2014-01-01

Methods for the generation of substrates presenting biomolecules in a spatially controlled manner are enabling tools for applications in biosensor systems, microarray technologies, fundamental biological studies and biointerface science. We have implemented a method to create biomolecular patterns by using light to control the direct covalent immobilization of biomolecules onto benzophenone-modified glass substrates. We have generated substrates presenting up to three different biomolecules patterned in sequence, and demonstrate biomolecular photopatterning on corrugated substrates. The chemistry of the underlying monolayer was optimized to incorporate poly(ethylene glycol) to enable adhesive cell adhesion onto patterned extracellular matrix proteins. Substrates were characterized with contact angle goniometry, AFM, and immunofluorescence microscopy. Importantly, radioimmunoassays were performed to quantify the site density of immobilized biomolecules on photopatterned substrates. Retention of function of photopatterned proteins was demonstrated both by native ligand recognition and cell adhesion to photopatterned substrates, revealing that substrates generated with this method are suitable for probing specific cell receptor-ligand interactions. This molecularly general photochemical patterning method is an enabling tool that will allow the creation of substrates presenting both biochemical and topographical variation, which is an important feature of many native biointerfaces. PMID:21793535

An air-based corrugated cavity-receiver for solar parabolic trough concentrators

International Nuclear Information System (INIS)

Bader, Roman; Pedretti, Andrea; Barbato, Maurizio; Steinfeld, Aldo

2015-01-01

Highlights: • We analyze a novel tubular cavity-receiver for solar parabolic trough collectors. • Four-fold solar concentration ratio is reached compared to conventional receivers. • Efficient operation at up to 500 °C is possible. • The pumping power requirement is found to be acceptably low. - Abstract: A tubular cavity-receiver that uses air as the heat transfer fluid is evaluated numerically using a validated heat transfer model. The receiver is designed for use on a large-span (9 m net concentrator aperture width) solar parabolic trough concentrator. Through the combination of a parabolic primary concentrator with a nonimaging secondary concentrator, the collector reaches a solar concentration ratio of 97.5. Four different receiver configurations are considered, with smooth or V-corrugated absorber tube and single- or double-glazed aperture window. The collector’s performance is characterized by its optical efficiency and heat loss. The optical efficiency is determined with the Monte Carlo ray-tracing method. Radiative heat exchange inside the receiver is calculated with the net radiation method. The 2D steady-state energy equation, which couples conductive, convective, and radiative heat transfer, is solved for the solid domains of the receiver cross-section, using finite-volume techniques. Simulations for Sevilla/Spain at the summer solstice at solar noon (direct normal solar irradiance: 847 W m −2 , solar incidence angle: 13.9°) yield collector efficiencies between 60% and 65% at a heat transfer fluid temperature of 125 °C and between 37% and 42% at 500 °C, depending on the receiver configuration. The optical losses amount to more than 30% of the incident solar radiation and constitute the largest source of energy loss. For a 200 m long collector module operated between 300 and 500 °C, the isentropic pumping power required to pump the HTF through the receiver is between 11 and 17 kW

Theory of potentiostatic current transients for coupled catalytic reaction at random corrugated fractal electrode

International Nuclear Information System (INIS)

Jha, Shailendra K.; Kant, Rama

2010-01-01

We developed a mathematical model for the first order homogeneous catalytic chemical reaction coupled with an electron transfer (EC') on a rough working electrode. Results are obtained for the various roughness models of electrode corrugations, viz., (i) roughness as an exact periodic function, (ii) roughness as a random function with known statistical properties, and (iii) roughness as a random function with statistical self-affine fractality over a finite range of length scales. Method of Green's function is used in the formulation to obtain second-order perturbation (in roughness profile) expressions for the concentration, the local current density and the current transients. A general operator structure between these quantities and arbitrary roughness profile is emphasized. The statistically averaged (randomly rough) electrode response is obtained by an ensemble averaging over all possible surface configurations. An elegant mathematical formula between the average electrochemical current transient and surface structure factor or power-spectrum of roughness is obtained. This formula is used to obtain an explicit equation for the current on an approximately self-affine (or realistic) fractal electrode with a limited range of length scales of irregularities. This description of realistic fractal is obtained by cutoff power law power-spectrum of roughness. The realistic fractal power-spectrum consists of four physical characteristics, viz., the fractal dimension (D H ), lower (l) and upper (L) cutoff length scales of fractality and a proportionality factor (μ), which is related to the topothesy or strength of fractality. Numerical calculations are performed on final results to understand the effect of catalytic reaction and fractal morphological characteristics on potentiostatic current transients.

Moiré superlattice-level stick-slip instability originated from geometrically corrugated graphene on a strongly interacting substrate

Science.gov (United States)

Shi, Ruoyu; Gao, Lei; Lu, Hongliang; Li, Qunyang; Ma, Tian-Bao; Guo, Hui; Du, Shixuan; Feng, Xi-Qiao; Zhang, Shuai; Liu, Yanmin; Cheng, Peng; Hu, Yuan-Zhong; Gao, Hong-Jun; Luo, Jianbin

2017-06-01

Two dimensional (2D) materials often exhibit novel properties due to various coupling effects with their supporting substrates. Here, using friction force microscopy (FFM), we report an unusual moiré superlattice-level stick-slip instability on monolayer graphene epitaxially grown on Ru(0 0 0 1) substrate. Instead of smooth friction modulation, a significant long-range stick-slip sawtooth modulation emerges with a period coinciding with the moiré superlattice structure, which is robust against high external loads and leads to an additional channel of energy dissipation. In contrast, the long-range stick-slip instability reduces to smooth friction modulation on graphene/Ir(1 1 1) substrate. The moiré superlattice-level slip instability could be attributed to the large sliding energy barrier, which arises from the morphological corrugation of graphene on Ru(0 0 0 1) surface as indicated by density functional theory (DFT) calculations. The locally steep humps acting as obstacles opposing the tip sliding, originates from the strong interfacial electronic interaction between graphene and Ru(0 0 0 1). This study opens an avenue for modulating friction by tuning the interfacial atomic interaction between 2D materials and their substrates.

Performance of LiCl Impregnated Mesoporous Material Coating over Corrugated Heat Exchangers in a Solid Sorption Chiller

Directory of Open Access Journals (Sweden)

Hongzhi Liu

2018-06-01

Full Text Available The composite material made by impregnating 40 wt. % lithium chloride (LiCl into the mesopores of a kind of natural porous rock (Wakkanai Siliceous Shale: WSS micropowders (short for “WSS + 40 wt. % LiCl” had been developed previously, and can be regenerated below 100 °C with a cooling coefficient of performance (COP of approximately 0.3 when adopted as a sorbent in a sorption cooler. In this study, experiments have been carried out on an intermittent solid sorption chiller with the WSS + 40 wt. % LiCl coating over two aluminum corrugated heat exchangers. Based on the experimental condition (regeneration temperature of 80 °C, condensation temperature of 30 °C in the desorption process; sorption temperature of 30 °C and evaporation temperature of 12 °C in the sorption process, the water sorption amount changes from 20 wt. % to 70 wt. % in one sorption cooling cycle. Moreover, a specific cooling power (SCP of 86 W/kg, a volumetric specific cooling power (VSCP of 42 W/dm3, and a specific sorption power of 170 W/kg can be achieved with a total sorption and desorption time of 20 min. The obtained cooling COP is approximately 0.16.

EXPERIMENTAL INVESTIGATION OF THE CONVECTIVE HEAT TRANSFER IN A SPIRALLY COILED CORRUGATED TUBE WITH RADIANT HEATING

Directory of Open Access Journals (Sweden)

Milan Đorđević

2017-12-01

Full Text Available The Archimedean spiral coil made of a transversely corrugated tube was exposed to radiant heating in order to represent a heat absorber of the parabolic dish solar concentrator. The main advantage of the considered innovative design solution is a coupling effect of the two passive methods for heat transfer enhancement - coiling of the flow channel and changes in surface roughness. The curvature ratio of the spiral coil varies from 0.029 to 0.234, while water and a mixture of propylene glycol and water are used as heat transfer fluids. The unique focus of this study is on specific boundary conditions since the heat flux upon the tube external surfaces varies not only in the circumferential direction, but in the axial direction as well. Instrumentation of the laboratory model of the heat absorber mounted in the radiation field includes measurement of inlet fluid flow rate, pressure drop, inlet and outlet fluid temperature and 35 type K thermocouples welded to the coil surface. A thermal analysis of the experimentally obtained data implies taking into consideration the externally applied radiation field, convective and radiative heat losses, conduction through the tube wall and convection to the internal fluid. The experimental results have shown significant enhancement of the heat transfer rate compared to spirally coiled smooth tubes, up to 240% in the turbulent flow regime.

White-Light Emission and Structural Distortion in New Corrugated Two-Dimensional Lead Bromide Perovskites.

Science.gov (United States)

Mao, Lingling; Wu, Yilei; Stoumpos, Constantinos C; Wasielewski, Michael R; Kanatzidis, Mercouri G

2017-03-29

Hybrid inorganic-organic perovskites are developing rapidly as high performance semiconductors. Recently, two-dimensional (2D) perovskites were found to have white-light, broadband emission in the visible range that was attributed mainly to the role of self-trapped excitons (STEs). Here, we describe three new 2D lead bromide perovskites incorporating a series of bifunctional ammonium dications as templates which also emit white light: (1) α-(DMEN)PbBr 4 (DMEN = 2-(dimethylamino)ethylamine), which adopts a unique corrugated layered structure in space group Pbca with unit cell a = 18.901(4) Å, b = 11.782(2) Å, and c = 23.680(5) Å; (2) (DMAPA)PbBr 4 (DMAPA = 3-(dimethylamino)-1-propylamine), which crystallizes in P2 1 /c with a = 10.717(2) Å, b = 11.735(2) Å, c = 12.127(2) Å, and β = 111.53(3)°; and (3) (DMABA)PbBr 4 (DMABA = 4-dimethylaminobutylamine), which adopts Aba2 with a = 41.685(8) Å, b = 23.962(5) Å, and c = 12.000(2) Å. Photoluminescence (PL) studies show a correlation between the distortion of the "PbBr 6 " octahedron in the 2D layer and the broadening of PL emission, with the most distorted structure having the broadest emission (183 nm full width at half-maximum) and longest lifetime (τ avg = 1.39 ns). The most distorted member α-(DMEN)PbBr 4 exhibits white-light emission with a color rendering index (CRI) of 73 which is similar to a fluorescent light source and correlated color temperature (CCT) of 7863 K, producing "cold" white light.

An InP/Si heterojunction photodiode fabricated by self-aligned corrugated epitaxial lateral overgrowth

International Nuclear Information System (INIS)

Sun, Y. T.; Omanakuttan, G.; Lourdudoss, S.

2015-01-01

An n-InP/p-Si heterojunction photodiode fabricated by corrugated epitaxial lateral overgrowth (CELOG) method is presented. N-InP/p-Si heterojunction has been achieved from a suitable pattern containing circular shaped openings in a triangular lattice on the InP seed layer on p-Si substrate and subsequent CELOG of completely coalesced n-InP. To avoid current path through the seed layer in the final photodiode, semi-insulating InP:Fe was grown with adequate thickness prior to n-InP growth in a low pressure hydride vapor phase epitaxy reactor. The n-InP/p-Si heterointerface was analyzed by scanning electron microscopy and Raman spectroscopy. Room temperature cross-sectional photoluminescence (PL) mapping illustrates the defect reduction effect in InP grown on Si by CELOG method. The InP PL intensity measured above the InP/Si heterojunction is comparable to that of InP grown on a native planar substrate indicating low interface defect density of CELOG InP despite of 8% lattice mismatch with Si. The processed n-InP/p-Si heterojunction photodiodes show diode characteristics from the current-voltage (I-V) measurements with a dark current density of 0.324 mA/cm 2 at a reverse voltage of −1 V. Under the illumination of AM1.5 conditions, the InP/Si heterojunction photodiode exhibited photovoltaic effect with an open circuit voltage of 180 mV, a short circuit current density of 1.89 mA/cm 2 , an external quantum efficiency of 4.3%, and an internal quantum efficiency of 6.4%. This demonstration of epitaxially grown InP/Si heterojunction photodiode will open the door for low cost and high efficiency solar cells and photonic integration of III-Vs on silicon

An experimental study on the application of polyalcohol solid-solid phase change materials in solar drying with cross-corrugated solar air collectors

Science.gov (United States)

Gao, W. F.; Lin, W. X.; Liu, T.; Li, M.

2017-11-01

In this paper, two identical solar driers with the same cross-corrugated solar air collectors and drying chamber were developed, one with phase-change materials (PCMs) and the other without PCMs. These two solar drying systems were tested in typical sunny and cloudy days in Kunming and their thermal performances were analyzed. The experimental results show that the temperature changing is smoother in the collector with the PCMs, which is beneficial for the drying as the useful drying time was prolonged. The same trend was also found in the chamber with the PCMs. The PCMs in solar drying system was found to play a role in temperature regulating. There were several cycles of heat charging-discharging in a cloudy testing day while the temperatures on collectors and in chambers with the polyalcohol PCMs is higher than each phase-change temperature. Nevertheless, there was only one cycle of heat charging-discharging in a sunny testing day. The collector with PCMs has higher daily useful heat gain than the collector without PCMs.

Liquid Metal Droplet and Micro Corrugated Diaphragm RF-MEMS for reconfigurable RF filters

Science.gov (United States)

Irshad, Wasim

detail and have proved pivotal to this work. The second part of the dissertation focuses on the Liquid Metal Droplet RF-MEMS. A novel tunable RF MEMS resonator that is based upon electrostatic control over the morphology of a liquid metal droplet (LMD) is conceived. We demonstrate an LMD evanescent-mode cavity resonator that simultaneously achieves wide analog tuning from 12 to 18 GHz with a measured quality factor of 1400-1840. A droplet of 250-mum diameter is utilized and the applied bias is limited to 100 V. This device operates on a principle called Electro-Wetting On Dielectric (EWOD). The liquid metal employed is a non-toxic eutectic alloy of Gallium, Indium and Tin known as Galinstan. This device also exploits interfacial surface energy and viscous body forces that dominate at nanoliter scale. We then apply our Liquid Metal Droplet (LMD) RF-MEMS architecture to demonstrate a continuously tunable electrostatic Ku-Band Filter. A 2-pole bandpass filter with measured insertion loss of less than 0.4dB and 3dB FBW of 3.4% is achieved using a Galinstan droplet of 250mum diameter and bias limited to 100V. We demonstrate that the LMD is insensitive to gravity by performing inversion and tilt experiments. In addition, we study its thermal tolerance by subjecting the LMD up to 150° C. The third part of the dissertation is dedicated to the Micro-Corrugated Diaphragm (MCD) RF-MEMS. We present an evanescent-mode cavity bandpass filter with state-of-the-art RF performance metrics like 4:1 tuning ratio from 5 to 20 GHz with less than 2dB insertion loss and 2-6% 3dB bandwidth. Micro-Corrugated Diaphragm (MCD) is a novel electrostatic MEMS design specifically engineered to provide large-scale analog deflections necessary for such continuous and wide tunable filtering with very high quality factor. We demonstrate a 1.25mm radius and 2mum thick Gold MCD which provides 30mum total deflection with nearly 60% analog range. We also present a detailed and systematic MCD design

Study of turbulent flows loaded with particles. Application to the particulate fouling of corrugated plate heat exchangers

International Nuclear Information System (INIS)

Kouidri, Frederic

1997-01-01

This work is a numerical and experimental study of the behaviour of a turbulent flow loaded with solid particles. It involves the particulate fouling of plate heat exchangers used in industrial field. Visual observation and LDA measurements inside a mock-up show the presence of large coherent vortices and confirm the tight link between particulate deposition and flow field. The vortices participate to the creation of preferential areas where the particles are in contact with the wall, and they shape the deposit according to a precise mechanism. Two processes of deposit removal have also been shown. Hydraulic phenomena and particles behaviours pointed out in the experiment are compared to different typical samples in a bibliographic survey. The use of the a software for computational fluid dynamics (TRIO developed at the Commissariat a l'Energie Atomique) completed the experimental results by predicting the particles behaviour into the turbulent flow. The approach is based on a connection between a pseudo-direct simulation of the turbulent flow and a Lagrangian model for particles paths. The results show good agreements, qualitatively speaking, between numerical predictions and experimental measurement. The arrangement of the deposit onto the corrugated surface is globally well described by numerical simulation. The influence of some parameters on deposition process such as the flow (corresponding to Re=5000 or Re=10000), the horizontal or vertical position of the channel or the particles diameter (d p =100 μm or d p =25 μm) has been studied. (author) [fr

Effects of hot electron emission on a low-conductivity tetracyanoethylene polymer layer including studies of the corrugation of the film surface

International Nuclear Information System (INIS)

Lorenz, K.L.; Mousa, M.S.

2003-01-01

The effect of strong field electron emission (FEE) on a tetracyanoethylene (TCNE) polymer layer was studied by Field Ion Microscopy (FIM) using TCNE and Ne as the imaging gases. The TCNE polymer was formed on each tungsten tip by radical polymerisation before FEE. The FIM images show field emission spots all over the surface of the tip. The FEM images show a random distribution of several field emission areas at the onset of FEE. After sometime at a current of about 1 μA, there is a transition to higher currents at the same voltage, in which the electron emission pattern changes to have only one emitting area. After this transition, two different types of FIM images were observed, depending on the imaging gas that was used. Neon FIM images at low tip voltages show spots in the areas where the electron emission current was greatest, and at much higher voltages these images show emission from other areas with lower surface corrugation. However, the FIM images with TCNE as the imaging gas do not show any differences between the areas with and without electron emission. The FIM images remain as before FEE, which can be explained by the formation of a new polymer by the reaction of the surface layer with the imaging gas. It is assumed that chemically reactive fragments at the polymer/vacuum interface, which are needed for the polymerisation reaction, are formed by pyrolysis and sputtering processes during FEE

In search of loyalty: private label packaging solutions for the retail grocery industry

OpenAIRE

Bullen, Christine Angela Holly

2006-01-01

The U.S. corrugated packaging industry is highly concentrated, competitive and mature, facing only modest growth in the United States. The objective of this paper is to understand the opportunity that private label grocery products present to the corrugated packaging industry and how Weyerhaeuser Company might increase demand of corrugated boxes. Industry analyses of both the U.S. retail and corrugated packaging industry are provided in conjunction with summaries of major firms in the respect...

Investigation the Potential Replacement of the Old Corrugated Container (OCC and Poplar Wood Flour Instead of Wheat Flour such as Urea-formaldehyde Adhesive Filler in the Plywood Industry

Directory of Open Access Journals (Sweden)

Kazem D.Hosseini

2012-01-01

Full Text Available Considering the value and importance of wheat flour in our country, replacement of a new type of filler instead of wheat flour in glue combination in plywood industry is necessary. In this study the possibility of using wood flour of poplar and OCC (old corrugated container fiber as filler in the combination of urea formaldehyde glue has been studied. The plywood was manufactured from Poplar species (in core of plywood and Hornbeam veneer (in back and face of plywood on the basis of the standard 3210 of ISIRI (Institute of Standards and Industrial Researches of Iran and the physical and mechanical properties of experimental plywood were measured. The results of statistical analysis of variance and Least Significant Difference (LSD showed that Mechanical and physical properties of samples made with fine OCC were more than that of control samples (the Samples made with wheat flour filler. The results also showed physical and mechanical properties of plywood increase by adding 10 to 15 percent of OCC to adhesive

Flexible cryogenic conduit

International Nuclear Information System (INIS)

Brindza, P.D.; Wines, R.R.; Takacs, J.J.

1999-01-01

A flexible and relatively low cost cryogenic conduit is described. The flexible cryogenic conduit of the present invention comprises a first inner corrugated tube with single braided serving, a second outer corrugated tube with single braided serving concentric with the inner corrugated tube, and arranged outwardly about the periphery of the inner corrugated tube and between the inner and outer corrugated tubes: a superinsulation layer; a one half lap layer of polyester ribbon; a one half lap layer of copper ribbon; a spirally wound refrigeration tube; a second one half lap layer of copper ribbon; a second one half lap layer of polyester ribbon; a second superinsulation layer; a third one half lap layer of polyester ribbon; and a spirally wound stretchable and compressible filament

On the generation of electromagnetic waves in the terahertz frequency range

International Nuclear Information System (INIS)

Namiot, V.A.; Shchurova, L.Yu.

2011-01-01

It is shown that a thin dielectric plate, which can act as an open dielectric waveguide, it is possible to produce amplification and generation of electromagnetic waves with frequencies in the terahertz range. For this purpose, we propose using a dielectric plate with a corrugated surface, in which case the electric field of the transverse electromagnetic wave in the waveguide has a periodic spatial structure in the local area near to the corrugation. Terahertz electromagnetic waves are excited by a beam of electrons moving in vacuum along the dielectric plate at a small distance from its corrugated surface. Corrugation period is chosen in order to ensure the most effective interaction of the electron beam with the first harmonic of the electric field induced by the corrugation. Amplification and generation of electromagnetic waves propagating in a dielectric waveguide is realized as a result of deceleration of the electron beam by a wave electric field induced by a corrugated dielectric surface in the zone near the corrugation. We discuss possible ways to create electron beams with the desired characteristics. We offer a way to stabilize the beam position above the plate, avoiding the bombardment of the plate by electrons. It is shown that it is possible to significantly increase the efficiency of the device through the recovery of energy that remains in the electrons after their interaction with the wave. -- Highlights: → We propose a scheme of a generator of radio waves in the terahertz range. → This scheme includes a corrugated dielectric plate, which can act as an open waveguide. → A strip electron beam is in vacuum near the dielectric corrugated surface. → Generation is achieved by converting electrons' energy into electromagnetic energy. → The waveguide wave extends perpendicularly to electron motion.

A Multifrequency Notch Filter for Millimeter Wave Plasma Diagnostics based on Photonic Bandgaps in Corrugated Circular Waveguides

Directory of Open Access Journals (Sweden)

Wagner D.

2015-01-01

Full Text Available Sensitive millimeter wave diagnostics need often to be protected against unwanted radiation like, for example, stray radiation from high power Electron Cyclotron Heating applied in nuclear fusion plasmas. A notch filter based on a waveguide Bragg reflector (photonic band-gap may provide several stop bands of defined width within up to two standard waveguide frequency bands. A Bragg reflector that reflects an incident fundamental TE11 into a TM1n mode close to cutoff is combined with two waveguide tapers to fundamental waveguide diameter. Here the fundamental TE11 mode is the only propagating mode at both ends of the reflector. The incident TE11 mode couples through the taper and is converted to the high order TM1n mode by the Bragg structure at the specific Bragg resonances. The TM1n mode is trapped in the oversized waveguide section by the tapers. Once reflected at the input taper it will be converted back into the TE11 mode which then can pass through the taper. Therefore at higher order Bragg resonances, the filter acts as a reflector for the incoming TE11 mode. Outside of the Bragg resonances the TE11 mode can propagate through the oversized waveguide structure with only very small Ohmic attenuation compared to propagating in a fundamental waveguide. Coupling to other modes is negligible in the non-resonant case due to the small corrugation amplitude (typically 0.05·λ0, where λ0 is the free space wavelength. A Bragg reflector for 105 and 140 GHz was optimized by mode matching (scattering matrix simulations and manufactured by SWISSto12 SA, where the required mechanical accuracy of ± 5 μm could be achieved by stacking stainless steel rings, manufactured by micro-machining, in a high precision guiding pipe. The two smooth-wall tapers were fabricated by electroforming. Several measurements were performed using vector network analyzers from Agilent (E8362B, ABmm (MVNA 8-350 and Rohde&Schwarz (ZVA24 together with frequency multipliers. The

Scattering of atoms by solid surfaces: A CCGM theory of diffraction by a one-dimensional stationary periodic wall

International Nuclear Information System (INIS)

Goodman, F.O.; Scribani, L.

1981-01-01

The CCGM theory of elastic atom--surface scattering, proposed by Cabrera, Celli, Goodman, and Manson [Surf. Sci. 19, 67 (1970)], is applied to the now-popular corrugated wall model of the scattering. Instead of the original ''hard'' wall, a ''softer'' wall, with finite potential step height, is used. The CCGM soft-wall results are compared with corresponding exact hard-wall results, for corrugations of the sinusoidal type and of other types, for example those with nondifferentiable corrugation functions. It is concluded that the CCGM soft-wall results agree well with the exact hard-wall results provided that neither the dimensionless corrugation amplitude nor the dimensionless atom wave number is too large, although no explanation of the reason for this agreement is given. The results are important because a typical exact calculation may be far more time consuming than is a typical CCGM calculation, particularly for the ''nastier'' corrugation functions

Grid for a fuel element

International Nuclear Information System (INIS)

1975-01-01

An illustrative embodiment of the invention has one or more corrugations formed in the surface of a fuel element grid for a nuclear reactor. Not only does the corrugation enhance the strength of the grid plate in which it is formed, but it also provides a simple and convenient means for regulating the reactor coolant pressure drop through an appropriate choice of the corrugation depth

Spacing and enclosure assembly for a reflecting thermal isolation panel

International Nuclear Information System (INIS)

Murdock, B.R.

1979-01-01

This invention concerns the thermal insulation assemblies and in particular a metallic assembly of stays and enclosures for a reflecting type panel used for insulation in nuclear reactors. Great flexibility is achieved by a corrugated strip placed edgewise around all the first reflecting insulating sheet. A second reflecting insulating sheet is then superposed on this corrugated strip which acts as a thickness spacer along the periphery of both sheets and also hermetically closes the intermediate space. The corrugations of the edge strip allow both sheets to be curved lengthwise or crosswise without causing their spacing to vary. These corrugations simply open like the pleats of an accordeon or a fan to fit the curve of the greatest radius [fr

Theoretical and experimental studies on in-plane stiffness of integrated container structure

Directory of Open Access Journals (Sweden)

Xiaoxiong Zha

2016-03-01

Full Text Available This article presents analytical, numerical, and experimental studies on the in-plane stiffness of container buildings. First, based on diaphragm theory, parallel corrugated direction stiffness of corrugated sheet has been deduced, and based on energy method, shear modulus of two elastic principal directions of orthotropic plate has been deduced, and through stiffness conversion method, the stiffness relationship between parallel corrugated direction and vertical corrugated direction has been obtained. Combined with container frame, the container stiffness of loading end and non-loading end, as bottom side beam fixed, has been obtained. Second, through the software Abaqus, full-scale container model has been established. The loading–displacement curve of finite element model has been compared with theoretical analysis and has a good agreement. Third, through 20 and 40 ft container, corresponding experimental verification has been done, and by comparison of container stiffness, the theoretical analysis and finite element simulation have been verified. Finally, based on verified finite element model, parametric analysis of corrugated sheet size, corrugated sheeting cross section, elasticity modulus of top side beam, and every plate action for container stiffness have been given. Research result has made feasible in design and construction of container buildings and can provide some references to corresponding specification preparation.

Threshold and Lennard-Jones resonances and elastic lifetimes in the scattering of atoms from crystalline surfaces

International Nuclear Information System (INIS)

Garcia, N.

1978-01-01

The GR method for solving the scattering equations of atoms from a hard corrugated surface is applied on accelerated particles above a hard corrugated surface and a hard corrugated surface with an attractive well. The solutions are given for the Rayleigh hypothesis that under the range of corrugation presented in this paper leads to the exact ones. Threshold resonances are studied observing that the appearance and disappearance of beams must be for a general theory with vertical tangent. The structure of the Lennard-Jones resonances given for the model mentioned above. For the first time it is stressed that Lennard-Jones resonances are not observed in metal surfaces in general, and, accordingly, they are unobserved in compact metallic surfaces. This is correlated with the fact that diffraction has not been observed. Both facts are due to the very weak corrugation of the gas-metal interaction potential. According to our results, the Lennard-Jones resonances in metals present greater difficulties to be observed experimentally. It is also noted that the absence of diffraction in compact metal surfaces is because they are almost plane and not because of the Debye-Waller effect. Finally, the lifetimes of the atoms at the crystal surfaces are calculated. These are larger, the smaller the incident energy and the larger the corrugation. But the lifetimes are particularly large at resonance conditions (10 -11 s). (Auth.)

Core design for use with precision composite reflectors

Science.gov (United States)

Porter, Christopher C. (Inventor); Jacoy, Paul J. (Inventor); Schmitigal, Wesley P. (Inventor)

1992-01-01

A uniformly flexible core, and method for manufacturing the same, is disclosed for use between the face plates of a sandwich structure. The core is made of a plurality of thin corrugated strips, the corrugations being defined by a plurality of peaks and valleys connected to one another by a plurality of diagonal risers. The corrugated strips are orthogonally criss-crossed to form the core. The core is particularly suitable for use with high accuracy spherically curved sandwich structures because undesirable stresses in the curved face plates are minimized due to the uniform flexibility characteristics of the core in both the X and Y directions. The core is self venting because of the open geometry of the corrugations. The core can be made from any suitable composite, metal, or polymer. Thermal expansion problems in sandwich structures may be minimized by making the core from the same composite materials that are selected in the manufacture of the curved face plates because of their low coefficients of thermal expansion. Where the strips are made of a composite material, the core may be constructed by first cutting an already cured corrugated sheet into a plurality of corrugated strips and then secondarily bonding the strips to one another or, alternatively, by lying a plurality of uncured strips orthogonally over one another in a suitable jig and then curing and bonding the entire plurality of strips to one another in a single operation.

Magnetic anisotropy of cobalt nanoparticle 2D arrays grown on corrugated MnF{sub 2}(1 1 0) and CaF{sub 2}(1 1 0) surfaces

Energy Technology Data Exchange (ETDEWEB)

Baranov, D.A., E-mail: dbaranov@mail.ioffe.ru [Ioffe Physical-Technical Institute, Russian Academy of Sciences, 26 Polytechnicheskaya str., St. Petersburg 194021 (Russian Federation); Krichevtsov, B.B.; Gastev, S.V.; Banschikov, A.G.; Fedorov, V.V. [Ioffe Physical-Technical Institute, Russian Academy of Sciences, 26 Polytechnicheskaya str., St. Petersburg 194021 (Russian Federation); Koshmak, K.V. [Ioffe Physical-Technical Institute, Russian Academy of Sciences, 26 Polytechnicheskaya str., St. Petersburg 194021 (Russian Federation); Dipartimento di Ingegneria dei Materiali e dell’Ambiente, Università di Modena e Reggio Emilia, Via Vignolese 905, 41100 Modena (Italy); Suturin, S.M.; Sokolov, N.S. [Ioffe Physical-Technical Institute, Russian Academy of Sciences, 26 Polytechnicheskaya str., St. Petersburg 194021 (Russian Federation)

2013-02-15

Cobalt nanoparticle 2D arrays with different effective thicknesses of cobalt layer (2 nm < d{sub eff} < 10 nm) were grown by molecular beam epitaxy on CaF{sub 2}(1 1 0)/Si(0 0 1) and MnF{sub 2}(1 1 0)/CaF{sub 2}(1 1 0)/Si(0 0 1) substrates with corrugated morphology of the surface. Surface morphology analysis showed that for effective thickness of cobalt layer d{sub eff} = 5 nm the lateral dimensions of cobalt islands are about 5–10 nm and the distances between the islands differs in a half along and across the grooves. In both types of the heterostructures the shape of hysteresis loops measured by LMOKE depend on orientation of in-plane magnetic field relative to the direction of the grooves. The azimuthal dependence of coercive field H{sub c} in Co/CaF{sub 2}(1 1 0)/Si(0 0 1) structures corresponds to Stoner–Wohlfarth model's predictions, which takes into account the anisotropy of individual particles. In contrast to that, in Co/MnF{sub 2}(1 1 0)/CaF{sub 2}(1 1 0)/Si(0 0 1) structures these dependences are analogous to those predicted by the model based on account of magnetic–dipole interaction between particles which are placed in chains (chain-of-spheres-model). Possible explanations of the difference in magnetic anisotropy are suggested.

A FEW CONSIDERATIONS ABOUT TRADE FAIR STANDS DESIGN

Directory of Open Access Journals (Sweden)

NEIDONI Nadina

2017-05-01

Full Text Available The paper presents some aspects related to the design of a trade fair stand, advertising a company specialized in the fabrication of corrugated fibre board packaging. The first section reviews shortly the main features of the industrial design. The second section deals with the structural conception of successful trade shows. Further, the importance of the package in the marketing matters is addressed. In this context corrugated fibreboard, as secondary or tertiary material is essential. In the final section, a comparison between two trade fair stands, representing a corrugated fibreboard company are presented.

Numerical and experimental investigation of bump foil mechanical behaviour

DEFF Research Database (Denmark)

Larsen, Jon Steffen; Cerda Varela, Alejandro Javier; Santos, Ilmar

2014-01-01

Corrugated foils are utilized in air foil bearings to introduce compliance and damping thus accurate mathematical predictions are important. A corrugated foil behaviour is investigated experimentally as well as theoretically. The experimental investigation is performed by compressing the foil...

Storage frame for long fuel elements for nuclear reactors

International Nuclear Information System (INIS)

Ristow, U.; Krainer, F.; Heinz, G.

1986-01-01

Vertical shafts with a cross section suitable for the fuel element cross section and made of metal can have corrugations for spacing from one another. These corrugations are machined parallel to the wall surface of the shafts. One thus obtains great accuracy of distancing. (orig./HP) [de

Technology Applications Report.

Science.gov (United States)

1992-08-01

generators for SDI to power research supports the theory , a power microwaves could pro- directed energy weapons. The series of microwave generators that duce... UGTED -- permitting high fiber density and a POLL CORRUGATING POLLS uniform distribution of fibers in theS... V • . •-composite. CORRUGATED PANEL c-st

Using bamboo (Bambusa vulgaris) as a field drainage material in ...

African Journals Online (AJOL)

user

shaped ceramic tile, circular clay tile, concrete tile, bituminized fibre perforated pipe, perforated smooth plastic pipe to corrugated plastic pipe. Currently, corrugated pipes are frequently used, although clay and concrete pipes are still being used as well. The use of drainage pipes made of various assorted materials is.

Geologic continuous casting below continental and deep-sea detachment faults and at the striated extrusion of Sacsayhuaman, Peru

Science.gov (United States)

Spencer, J.E.

1999-01-01

In the common type of industrial continuous casting, partially molten metal is extruded from a vessel through a shaped orifice called a mold in which the metal assumes the cross-sectional form of the mold as it cools and solidifies. Continuous casting can be sustained as long as molten metal is supplied and thermal conditions are maintained. I propose that a similar process produced parallel sets of grooves in three geologic settings, as follows: (1) corrugated metamorphic core complexes where mylonized mid-crustal rocks were exhumed by movement along low-angle normal faults known as detachment faults; (2) corrugated submarine surfaces where ultramafic and mafic rocks were exhumed by normal faulting within oceanic spreading centers; and (3) striated magma extrusions exemplified by the famous grooved outcrops at the Inca fortress of Sacsayhuaman in Peru. In each case, rocks inferred to have overlain the corrugated surface during corrugation genesis molded and shaped a plastic to partially molten rock mass as it was extruded from a moderate- to high-temperature reservoir.

Inclement Weather Crater Repair Tool Kit

Science.gov (United States)

2017-11-30

9. Corrugated steel quadcons. ....................................................................................................... 14 Figure 10...Saw cutting around crater upheaval. ERDC/GSL TR-17-26 6 The excavation team is responsible for breaking up the damaged portland cement ...in the table located on Sheet 2 in Appendix A. The corrugated steel quadcons (Item 1) are equipped with double swing doors on both ends of the

Possible origin and significance of extension-parallel drainages in Arizona's metamophic core complexes

Science.gov (United States)

Spencer, J.E.

2000-01-01

The corrugated form of the Harcuvar, South Mountains, and Catalina metamorphic core complexes in Arizona reflects the shape of the middle Tertiary extensional detachment fault that projects over each complex. Corrugation axes are approximately parallel to the fault-displacement direction and to the footwall mylonitic lineation. The core complexes are locally incised by enigmatic, linear drainages that parallel corrugation axes and the inferred extension direction and are especially conspicuous on the crests of antiformal corrugations. These drainages have been attributed to erosional incision on a freshly denuded, planar, inclined fault ramp followed by folding that elevated and preserved some drainages on the crests of rising antiforms. According to this hypothesis, corrugations were produced by folding after subacrial exposure of detachment-fault foot-walls. An alternative hypothesis, proposed here, is as follows. In a setting where preexisting drainages cross an active normal fault, each fault-slip event will cut each drainage into two segments separated by a freshly denuded fault ramp. The upper and lower drainage segments will remain hydraulically linked after each fault-slip event if the drainage in the hanging-wall block is incised, even if the stream is on the flank of an antiformal corrugation and there is a large component of strike-slip fault movement. Maintenance of hydraulic linkage during sequential fault-slip events will guide the lengthening stream down the fault ramp as the ramp is uncovered, and stream incision will form a progressively lengthening, extension-parallel, linear drainage segment. This mechanism for linear drainage genesis is compatible with corrugations as original irregularities of the detachment fault, and does not require folding after early to middle Miocene footwall exhumations. This is desirable because many drainages are incised into nonmylonitic crystalline footwall rocks that were probably not folded under low

The Experimental Verification of Gaussian Beam Coupling for ECH Transmission Line at 400 GHz

Directory of Open Access Journals (Sweden)

Choe Mun Seok

2017-01-01

Full Text Available We design a quasi-optical transmission line system for a 400 GHz gyrotron beam. The 400GHz Gaussian beam is injected to a corrugated waveguide bounced from a quasi-optical mirror. From detailed 2D field patterns of the output beam emitted from the corrugated waveguide, we analyze the mode contents and the source of non-ideal beam expansion

Ultra-compact Higher-Order-Mode Pass Filter in a Silicon Waveguide

DEFF Research Database (Denmark)

Guan, Xiaowei; Frandsen, Lars Hagedorn; Ding, Yunhong

2015-01-01

An 3.7 μm long higher-order-mode pass filter with an extinction ratio larger than 20 dB is demonstrated in a 1D corrugated silicon multimode waveguide......An 3.7 μm long higher-order-mode pass filter with an extinction ratio larger than 20 dB is demonstrated in a 1D corrugated silicon multimode waveguide...

Photovoltaic effect in ferroelectric ceramics

Science.gov (United States)

Epstein, D. J.; Linz, A.; Jenssen, H. P.

1982-01-01

The ceramic structure was simulated in a form that is more tractable to correlation between experiment and theory. Single crystals (of barium titanate) were fabricated in a simple corrugated structure in which the pedestals of the corrugation simulated the grain while the intervening cuts could be filled with materials simulating the grain boundaries. The observed photovoltages were extremely small (100 mv).

Theoretical atomic-force-microscopy study of a stepped surface: Nonlocal effects in the probe

International Nuclear Information System (INIS)

Girard, C.

1991-01-01

The interaction force between a metallic tip and a nonplanar dielectric surface is derived from a nonlocal formalism. A general formulation is given for the case of a spherical tip of nanometer size and for surfaces of arbitrary shapes (stepped surfaces and single crystals adsorbed on a planar surface). The dispersion part of the attractive force is obtained from a nonlocal theory expressed in terms of generalized electric susceptibilities of the two constituents. Implications for atomic force microscopy in attractive modes are discussed. In this context, the present model indicates two different forms of corrugation: those due to the protuberance present on the tip leading to atomic corrugations; nanometer-sized corrugations detected in the attractive region by the spherical part of the tip

The effects of road crossings on prairie stream habitat and function

Science.gov (United States)

Bouska, Wesley W.; Keane, Timothy; Paukert, Craig P.

2010-01-01

Improperly designed stream crossing structures may alter the form and function of stream ecosystems and habitat and prohibit the movement of aquatic organisms. Stream sections adjoining five concrete box culverts, five low-water crossings (concrete slabs vented by one or multiple culverts), and two large, single corrugated culvert vehicle crossings in eastern Kansas streams were compared to reference reaches using a geomorphologic survey and stream classification. Stream reaches were also compared upstream and downstream of crossings, and crossing measurements were used to determine which crossing design best mimicked the natural dimensions of the adjoining stream. Four of five low-water crossings, three of five box culverts, and one of two large, single corrugated pipe culverts changed classification from upstream to downstream of the crossings. Mean riffle spacing upstream at low-water crossings (8.6 bankfull widths) was double that of downstream reaches (mean 4.4 bankfull widths) but was similar upstream and downstream of box and corrugated pipe culverts. There also appeared to be greater deposition of fine sediments directly upstream of these designs. Box and corrugated culverts were more similar to natural streams than low-water crossings at transporting water, sediments, and debris during bankfull flows.

Study on Transport Packages Used for Food Freshness Preservation based on ANSYS Thermal Analysis

Directory of Open Access Journals (Sweden)

Yu Ying

2016-12-01

Full Text Available In recent years, as the Chinese consumption level increases, the consumption quantity of high-value fruits, vegetables and seafood products have been increasing year by year. As a consequence, the traffic volume of refrigerated products also increases yearly and the popularization degree of the cold-chain transportation enhances. A low-temperature environment should be guaranteed during transportation, thus there is about 40% of diesel oil should be consumed by the refrigerating system and the cold-chain transportation becomes very costly. This study aimed to explore a method that could reduce the cost of transport packages of refrigerated products. On the basis of the heat transfer theory and the fluid mechanics theory, the heat exchange through corrugated cases during the operation of refrigerating system was analyzed, the heat transfer process of corrugated cases and refrigerator van was theoretically analyzed and the heat balance equation of corrugated cases was constructed. Besides, this study simulated the temperature field of the corrugated box during transportation. The temperature of the goods was changed through different cooling temperature to calculate the minimum energy consumption, so as to achieve the best refrigeration transport packaging program.

Efficient simulation of flow and heat transfer in arbitrarily shaped pipes

OpenAIRE

Rosen Esquivel, P.I.

2012-01-01

The transport of fluids through pipes is a very common application. Corrugated pipes have characteristics such as local stiffness and flexibility that makes them convenient in several application areas such as offshore LNG (Liquefied Natural Gas) transfer, cryogenic engineering, domestic appliances, etc. Nonetheless, the introduction of pipes with corrugated walls increases the difficulty of simulating flow and heat transfer in these type of pipes. The present thesis addresses the development...

Imploded test-chamber for an ISR intersection

CERN Multimedia

CERN PhotoLab

1977-01-01

At the ISR intersection points the vacuum chambers had to be as "transparent" as possible, for the p-p collision product particles to reach the detectors with minimum hindrance. This meant the choice of a light, yet very strong, metal; minimum thickness; and corrugation for mechanical strength. The test-chamber seen here was made of 0.6 mm thick corrugated titanium, obviously not strong enough to withstand the atmospheric pressure.

Modelos de otimização para o problema de corte nas indústrias de papel e papelão e de móveis Optimization models of the cutting stock problem in furniture and corrugated paper industries

Directory of Open Access Journals (Sweden)

Reinaldo Morábito

1994-04-01

Full Text Available Este trabalho examina alguns modelos de otimização conhecidos da literatura para o problema de corte, e reporta uma experiência real da aplicação destes modelos numa indústria de papel e papelão (problema unidimensional e numa indústria de móveis (problema bidimensional. Também são discutidas algumas modificações nos modelos originais para incorporar restrições práticas dos processos de corte, tais como, unidades de estoque com tamanhos e custos diferentes, tolerância na demanda de clientes, entre outras. Alguns resultados computacionais são apresentados para um exemplo real da indústria de móveis, utilizando-se um microcomputador.This work examines some well-known optimization models for the cutting stock problem and reports a real experience of their application to a corrugated paper industry (one- dimensional problem and to a furniture industry (two-dimensional problem. It is also discussed some modifications in the original models to incorporate practical constraints of the cutting processes, such as tolerance in the customer orders, among others. Some computational results from a real example of the furniture industry are presented utilizing a micro-computer.

Pinning of superconducting vortices in MoGe/Au Thin nano–squares

Energy Technology Data Exchange (ETDEWEB)

Serrier-Garcia, Lise, E-mail: serriergarcia.lise@fys.kuleuven.be; Timmermans, Matias; Van de Vondel, Joris; Moshchalkov, Victor V.

2017-02-15

Highlights: • A scanning tunneling spectroscopy study of vortex patterns in mesoscopic superconducting squares is reported. • The impact of defects and corrugations inherently present in nanofabricated structures is explored. • Hillocks at the edge can attract and repulse vortices. • The small surface corrugation creates metastable states. • Vortex rotations during dynamical vortex penetrations are visualized. - Abstract: In this work, we report a scanning tunneling spectroscopy study of vortex patterns in mesoscopic superconducting squares and explore the impact of defects and corrugations inherently present in nanofabricated structures. We find that a hillock at the edge can function as an attractive or repulsive pinning center for vortices deforming the, theoretically predicted, symmetry-induced vortex configurations. In addition, we exploit the inherently present imperfections, creating metastable states, to visualize the dynamics of vortex penetration during magnetic field sweeps.

Study on the bending behavior of preflex beam

Science.gov (United States)

Wan, Lijuan; Gao, Qilang

2017-08-01

Preflex beam with corrugated web is a new type of beam structure for bridge engineering which is composed by corrugated steel sheet and preflex beam. This kind of structure has advantages of high load bearing capacity, good endurance, small height-span ratio, light self-weight, long-span capacity and stiffener free. It has good economy and competitive ability for middle or small span bridges, such as Highway Bridge, overpass and Railway Bridge.

Numerical investigation of the energy performance of a guideless irregular heat and mass exchanger with corrugated heat transfer surface for dew point cooling

International Nuclear Information System (INIS)

Xu, Peng; Ma, Xiaoli; Diallo, Thierno M.O.; Zhao, Xudong; Fancey, Kevin; Li, Deying; Chen, Hongbing

2016-01-01

The paper presents an investigation into the energy performance of a novel irregular heat and mass exchanger for dew point cooling which, compared to the existing flat-plate heat exchangers, removed the use of the channel supporting guides and implemented the corrugated heat transfer surface, thus expecting to achieve the reduced air flow resistance, increased heat transfer area, and improved energy efficiency (i.e. Coefficient of Performance (COP)) of the air cooling process. CFD simulation was carried out to determine the flow resistance (K) factors of various elements within the dry and wet channels of the exchanger, while the ‘finite-element’ based ‘Newton-iteration’ numerical simulation was undertaken to investigate its cooling capacity, cooling effectiveness and COP at various geometrical and operational conditions. Compared to the existing flat-plate heat and mass exchangers with the same geometrical dimensions and operational conditions, the new irregular exchanger could achieve 32.9%–37% higher cooling capacity, dew-point and wet-bulb effectiveness, 29.7%–33.3% higher COP, and 55.8%–56.2% lower pressure drop. While undertaking dew point air cooling, the irregular heat and mass exchanger had the optimum air velocity of 1 m/s within the flow channels and working-to-intake air ratio of 0.3, which allowed the highest cooling capacity and COP to be achieved. In terms of the exchanger dimensions, the optimum height of the channel was 5 mm while its length was in the range 1–2 m. Overall, the proposed irregular heat and mass exchanger could lead to significant enhanced energy performance compared to the existing flat-plate dew point cooling heat exchanger of the same geometrical dimensions. To achieve the same amount cooling output, the irregular heat and mass exchanger had the reduced size and cost against the flat-plate ones. - Highlights: • Numerical investigation of an irregular heat and mass exchanger was undertaken. • A �

Method of making a low energy gamma ray collimator

International Nuclear Information System (INIS)

Muehllehner, Gerd.

1975-01-01

Described herein is a method for making a low energy gamma ray collimator which involves corrugating lead foil strips by passing them through pinion wire rollers and gluing corrugated strips between straight strips using an adhesive such as epoxy to build up a honeycomb-like structure. A thin aluminum sheet is glued to both edges of the strips to protect them and to provide a more rigid assembly which may be sawed to a desired shape. (Patent Office Record)

Study on transport packages used for food freshness preservation based on thermal analysis

Science.gov (United States)

Yu, Ying

2016-12-01

In recent time, as the Chinese consumption level increases, the consumption quantity of high-value fruits, vegetables and seafood products have been increasing year by year. As a consequence, the traffic volume of refrigerated products also increases yearly and the popularization degree of the cold-chain transportation enhances. A low-temperature environment should be guaranteed during transportation, thus there is about 40% of diesel oil should be consumed by the refrigerating system and the cold-chain transportation becomes very costly. This study aimed to explore methods that could reduce the cost of transport packages of refrigerated products. On the basis of the heat transfer theory and the fluid mechanics theory, the heat exchanging process of corrugated cases during the operation of refrigerating system was analyzed, the heat transfer process of corrugated cases and refrigerator van was theoretically analyzed and the heat balance equation of corrugated cases was constructed.

Extrinsic morphology of graphene

International Nuclear Information System (INIS)

Li, Teng

2011-01-01

Graphene is intrinsically non-flat and corrugates randomly. Since the corrugating physics of atomically thin graphene is strongly tied to its electronics properties, randomly corrugating morphology of graphene poses a significant challenge to its application in nanoelectronic devices for which precise (digital) control is the key. Recent studies revealed that the morphology of substrate-supported graphene is regulated by the graphene–substrate interaction, thus is distinct from the random intrinsic morphology of freestanding graphene. The regulated extrinsic morphology of graphene sheds light on new pathways to fine tune the properties of graphene. To guide further research to explore these fertile opportunities, this paper reviews recent progress on modeling and experimental studies of the extrinsic morphology of graphene under a wide range of external regulation, including two-dimensional and one-dimensional substrate surface features and one-dimensional and zero-dimensional nanoscale scaffolds (e.g. nanowires and nanoparticles)

An effective field study of the magnetic properties and critical behaviour at the surface Ising film

International Nuclear Information System (INIS)

Bengrine, M.; Benyoussef, A.; Ez-Zahraouy, H.; Mhirech, F.

1998-09-01

The influence of corrugation and disorder at the surface on the critical behaviour of a ferromagnetic spin-1/2 Ising film is investigated using mean-field theory and finite cluster approximation. It is found that the critical surface exponent β 1 follows closely the one of a perfect surface, in the two cases: corrugated surface and random equiprobable coupling surface. However, in the case of flat surface with random interactions the surface critical exponent β 1 depends on the concentration p of the strong interaction for p>p c =0,5, while for p≤p c , such critical exponent is independent on the value of p and is equal to the one of the perfect surface. Moreover, in the case of corrugated surface, the effective exponent for a layer z, β eff J(z,n), is calculated as a function of the number of steps at the surface. (author)

An experimental and theoretical study of decentralized gas fired liquid heating

Energy Technology Data Exchange (ETDEWEB)

Christensen, Rolf

1996-12-01

The effects on the energy situation in industry when gas fired liquid heaters replace steam have been determined by energy surveys performed in a brewery and a slaughterhouse, measurements of the performance and emissions from liquid heaters installed in these industries, and theoretical analyses of the potential energy. The theoretical study in the first part of the project provides information that allows assessment of the effects on the energy situation, of a part or complete conversion to decentralized heating, under the conditions prevailing in the industries concerned. The second part of the project focused on increasing the liquid heater efficiency and reducing emissions of carbon monoxide and hydrocarbons. Heat transfer and pressure drop for a corrugated tube was investigated experimentally. Empirical correlations for heat transfer and pressure drop for a corrugated tube were developed. These correlations were used in the design model that was developed within this project. The design model was validated against experimental data and data from an industrial application, where a section of the smooth heat exchanger tube was replaced with a corrugated tube. The results show that the design model predicts the outlet flue gas temperature and the heater efficiency quite accurately. The wall temperature at the first corrugation is also predicted with reasonable accuracy. These results make it possible to calculate the location where a corrugated tube can be inserted without causing subcooled boiling or severe fouling. It is shown that emissions of carbon monoxide and hydrocarbons can be held at low levels, even when conventional industrial burners are used. The use of nozzles that produce long soft flames increase the risk for large emissions of hydrocarbons and carbon monoxide. 125 refs, 89 figs, 16 tabs

Improvement activities to soil stabilization near Bolivia-Brazil gas pipeline crossing through an embankment over a corrugated drainage pipe, at Km 247 in Mato Grosso do Sul, Brazil; Melhorias para estabilidade do gasoduto Bolivia-Brasil em cruzamento de aterro sobre tubo de drenagem tipo ARMCO, no km 247 em Mato Grosso do Sul

Energy Technology Data Exchange (ETDEWEB)

Jorge, Kemal Vieira [TBG - Transportadora Brasileira Gasoduto Bolivia Brasil S.A., Rio de Janeiro, RJ (Brazil); Costa, Cesar Augusto [TBG - Transportadora Brasileira Gasoduto Bolivia Brasil S.A., Campo Grande, MS (Brazil). Gerencia Regional Centro Oeste (CRGO)

2005-07-01

A hundred and seventy kilometers from Campo Grande city, on Mato Grosso do Sul State, the Brasil-Bolivia Gas Pipeline crosses a 8,5 meters high landfill, over a drainage systems made of a 2,8 meters of diameter corrugated pipe. This drainage pipe was installed to allow the drainage of the valley, and the landfill above it was built so the Gas pipeline could cross easier the 80 meters deep and 30 degree vertices valley. This paper illustrates the work tasks and solutions taken to monitor and guarantee the integrity of the drainage and landfill structures, as well as the integrity of the Gas Pipeline. Some of the work tasks illustrated are the investigation of the support conditions of the Gas Pipeline, the analysis of a drainage system under the pipeline, on a rocky soil, the analysis of the stability of the landfill, the construction of a gravity retaining walls and the monitoring of the deformations on the drainage pipe. (author)

Asymmetric Response toward Molecular Fluorination in Binary Copper–Phthalocyanine/Pentacene Assemblies

DEFF Research Database (Denmark)

de Oteyza, D. G.; García Lastra, Juan Maria; Goiri, E.

2014-01-01

We report a didactic and simple example of the subtleness in the balance of intermolecular and molecule–substrate interactions and its effect on molecular self-assembly. The study is performed on two closely related molecular blends of copper phthalocyanines and pentacene, in each of which one of...... intermolecular interactions and a larger corrugation in the molecule–substrate interaction potential, results in a disordered layer. However, the difference between the two blend’s structures vanishes when substrates with less corrugated interaction potentials are used....

Experimental study of intense radiation in terahertz region based on cylindrical surface wave resonator

International Nuclear Information System (INIS)

Gong, Shaoyan; Ogura, Kazuo; Yambe, Kiyoyuki; Nomizu, Shintaro; Shirai, Akihiro; Yamazaki, Kosuke; Kawamura, Jun; Miura, Takuro; Takanashi, Sho; San, Min Thu

2015-01-01

Periodical corrugations structured on a cylindrical conductor have cylindrical surface waves (CSWs), which are reflected at the corrugation ends and form a CSW-resonator. In this paper, intense radiations in terahertz region based on the CSW-resonator are reported. The CSW-resonators with upper cut off frequencies in the modern IEEE G-band (110–300 GHz) are excited by a coaxially injected annular beam in a weakly relativistic region less than 100 kV. It is shown that there exists an oscillation starting energy for the CSW-resonator. Above the starting energy, very intense terahertz radiations on the order of kW are obtained. The operation frequencies in the range of 166–173 GHz and 182–200 GHz are obtained using two types of CSW-resonator with the different corrugation amplitude. Electromagnetic properties of the CSW-resonator can be controlled by the artificial structure and may play an important role in high-intensity terahertz generations and applications

Determining the in-plane Fermi surface topology in high Tc superconductors using angle-dependent magnetic quantum oscillations

International Nuclear Information System (INIS)

Harrison, N; McDonald, R D

2009-01-01

We propose a quantum oscillation experiment by which the rotation of an underdoped YBa 2 Cu 3 O 6+x sample about two different axes with respect to the orientation of the magnetic field can be used to infer the shape of the in-plane cross-section of corrugated Fermi surface cylinder(s). Deep corrugations in the Fermi surface are expected to give rise to nodes in the quantum oscillation amplitude that depend on the magnitude and orientation of the magnetic induction B. Because the symmetries of electron and hole cylinders within the Brillouin zone are expected to be very different, the topology can provide essential clues as to the broken symmetry responsible for the observed oscillations. The criterion for the applicability of this method to the cuprate superconductors (as well as other layered metals) is that the difference in quantum oscillation frequency 2ΔF between the maximum (belly) and minimum (neck) extremal cross-sections of the corrugated Fermi surface exceeds |B|. (fast track communication)

The Prandtl-Tomlinson model of friction with stochastic driving

Science.gov (United States)

Jagla, E. A.

2018-01-01

We consider the classical Prandtl-Tomlinson model of a particle moving on a corrugated potential, pulled by a spring. In the usual situation in which pulling acts at constant velocity \\dotγ , the model displays an average friction force σ that relates to \\dotγ (for small \\dotγ) as \\dotγ˜ (σ-σ_c){\\hspace{0pt}}^β , where σc is a critical friction force. The possible values of β are well known in terms of the analytical properties of the corrugated potential. We study here the situation in which the pulling has, in addition to the constant velocity term, a stochastic term of mechanical origin. We analytically show how this term modifies the force-velocity dependence close to the critical force, and give the value of β in terms of the analytical properties of the corrugation potential and the scaling properties of the stochastic driving, encoded in the value of its Hurst exponent.

Mode converters for generating the HE11 (gaussian-like) mode from TE01 in circular waveguide

International Nuclear Information System (INIS)

Doane, J.L.

1982-09-01

The HE11 mode in corrugated waveguide has a field distribution very close to that of an ideal gaussian mode. Its radiation pattern is symmetric about the waveguide axis and exhibits virtually no cross polarization. This work reports measurements on mode converters to transform the TE01 mode into HE11 for electron cyclotron heating (ECH) experiments. The first mode converter is a 28 degree bend in 1.094-inch I.D. circular waveguide which generates TM11 from TE01 with a measured efficiency of over 95% at 60 GHz. A second converter consists of a straight corrugated waveguide section of the same I.D. in which the corrugation depth increases gradually from zero to nominally a quarter wavelength. This section converts TM11 to HE11 with an efficiency of about 97%. The overall efficiency of conversion from TE01 to HE11 exceeds 91% over a measured range of 59.2 to 60.1 GHz

Localized Acoustic Surface Modes

KAUST Repository

Farhat, Mohamed

2015-08-04

We introduce the concept of localized acoustic surface modes (ASMs). We demonstrate that they are induced on a two-dimensional cylindrical rigid surface with subwavelength corrugations under excitation by an incident acoustic plane wave. Our results show that the corrugated rigid surface is acoustically equivalent to a cylindrical scatterer with uniform mass density that can be represented using a Drude-like model. This, indeed, suggests that plasmonic-like acoustic materials can be engineered with potential applications in various areas including sensing, imaging, and cloaking.

Changes in pectin methyl esterase activity with different packaging materials and stages of fruit harvesting during cold storage of pear cv. Punjab beauty

OpenAIRE

Kaur, Kirandeep; Dhillon, W. S.; Mahajan, B. V. C.

2012-01-01

Pear cv. Punjab Beauty has become quite popular in Punjab. Excessive softening during cold storage leading to low shelf life is the major factor limiting its wider adoption. Studies were, therefore, conducted to determine the firmness and pectin methyl esterase (PME) activity at 4 harvest dates (2nd, 3rd and 4th week of July, and 1st week of August). Various packaging materials i.e. corrugated fiber board boxes and crates with high and low density polyethylene liners, corrugated fiber board b...

Compensated electron and hole pockets in an underdoped high- Tc superconductor

Science.gov (United States)

Sebastian, Suchitra E.; Harrison, N.; Goddard, P. A.; Altarawneh, M. M.; Mielke, C. H.; Liang, Ruixing; Bonn, D. A.; Hardy, W. N.; Andersen, O. K.; Lonzarich, G. G.

2010-06-01

We report quantum oscillations in the underdoped high-temperature superconductor YBa2Cu3O6+x over a wide range in magnetic field 28≤μ0H≤85T corresponding to ≈12 oscillations, enabling the Fermi surface topology to be mapped to high resolution. As earlier reported by Sebastian [Nature (London) 454, 200 (2008)10.1038/nature07095], we find a Fermi surface comprising multiple pockets, as revealed by the additional distinct quantum oscillation frequencies and harmonics reported in this work. We find the originally reported broad low-frequency Fourier peak at ≈535T to be clearly resolved into three separate peaks at ≈460 , ≈532 , and ≈602T , in reasonable agreement with the reported frequencies of Audouard [Phys. Rev. Lett. 103, 157003 (2009)10.1103/PhysRevLett.103.157003]. However, our increased resolution and angle-resolved measurements identify these frequencies to originate from two similarly sized pockets with greatly contrasting degrees of interlayer corrugation. The spectrally dominant frequency originates from a pocket (denoted α ) that is almost ideally two-dimensional in form (exhibiting negligible interlayer corrugation). In contrast, the newly resolved weaker adjacent spectral features originate from a deeply corrugated pocket (denoted γ ). On comparison with band structure, the d -wave symmetry of the interlayer dispersion locates the minimally corrugated α pocket at the “nodal” point knodal=(π/2,π/2) , and the significantly corrugated γ pocket at the “antinodal” point kantinodal=(π,0) within the Brillouin zone. The differently corrugated pockets at different locations indicate creation by translational symmetry breaking—a spin-density wave has been suggested from the suppression of Zeeman splitting for the spectrally dominant pocket. In a broken-translational symmetry scenario, symmetry points to the nodal (α) pocket corresponding to holes, with the weaker antinodal (γ) pocket corresponding to electrons—likely responsible

Commissioning of inline ECE system within waveguide based ECRH transmission systems on ASDEX upgrade

Directory of Open Access Journals (Sweden)

Donné A.J.H.

2012-09-01

Full Text Available A CW capable inline electron cyclotron emission (ECE separation system for feedback control, featuring oversized corrugated waveguides, is commissioned on ASDEX upgrade (AUG. The system is based on a combination of a polarization independent, non-resonant, Mach-Zehnder diplexer equipped with dielectric plate beam splitters [2, 3] employed as corrugated oversized waveguide filter, and a resonant Fast Directional Switch, FADIS [4, 5, 6, 7] as ECE/ECCD separation system. This paper presents an overview of the system, the low power characterisation tests and first high power commissioning on AUG.

Electronically controllable spoof localized surface plasmons

Science.gov (United States)

Zhou, Yong Jin; Zhang, Chao; Yang, Liu; Xun Xiao, Qian

2017-10-01

Electronically controllable multipolar spoof localized surface plasmons (LSPs) are experimentally demonstrated in the microwave frequencies. It has been shown that half integer order LSPs modes exist on the corrugated ring loaded with a slit, which actually arise from the Fabry-Perot-like resonances. By mounting active components across the slit in the corrugated rings, electronic switchability and tunability of spoof LSPs modes have been accomplished. Both simulated and measured results demonstrate efficient dynamic control of the spoof LSPs. These elements may form the basis of highly integrated programmable plasmonic circuits in microwave and terahertz regimes.

Commissioning of inline ECE system within waveguide based ECRH transmission systems on ASDEX upgrade

Science.gov (United States)

Bongers, W. A.; Kasparek, W.; Doelman, N.; van den Braber, R.; van den Brand, H.; Meo, F.; de Baar, M. R.; Amerongen, F. J.; Donné, A. J. H.; Elzendoorn, B. S. Q.; Erckmann, V.; Goede, A. P. H.; Giannone, L.; Grünwald, G.; Hollman, F.; Kaas, G.; Krijger, B.; Michel, G.; Lubyako, L.; Monaco, F.; Noke, F.; Petelin, M.; Plaum, B.; Purps, F.; ten Pierik, J. G. W.; Schüller, C.; Slob, J. W.; Stober, J. K.; Schütz, H.; Wagner, D.; Westerhof, E.; Ronden, D. M. S.

2012-09-01

A CW capable inline electron cyclotron emission (ECE) separation system for feedback control, featuring oversized corrugated waveguides, is commissioned on ASDEX upgrade (AUG). The system is based on a combination of a polarization independent, non-resonant, Mach-Zehnder diplexer equipped with dielectric plate beam splitters [2, 3] employed as corrugated oversized waveguide filter, and a resonant Fast Directional Switch, FADIS [4, 5, 6, 7] as ECE/ECCD separation system. This paper presents an overview of the system, the low power characterisation tests and first high power commissioning on AUG.

Parameter study of simplified dragonfly airfoil geometry at Reynolds number of 6000.

Science.gov (United States)

Levy, David-Elie; Seifert, Avraham

2010-10-21

Aerodynamic study of a simplified Dragonfly airfoil in gliding flight at Reynolds numbers below 10,000 is motivated by both pure scientific interest and technological applications. At these Reynolds numbers, the natural insect flight could provide inspiration for technology development of Micro UAV's and more. Insect wings are typically characterized by corrugated airfoils. The present study follows a fundamental flow physics study (Levy and Seifert, 2009), that revealed the importance of flow separation from the first corrugation, the roll-up of the separated shear layer to discrete vortices and their role in promoting flow reattachment to the aft arc, as the leading mechanism enabling high-lift, low drag performance of the Dragonfly gliding flight. This paper describes the effect of systematic airfoil geometry variations on the aerodynamic properties of a simplified Dragonfly airfoil at Reynolds number of 6000. The parameter study includes a detailed analysis of small variations of the nominal geometry, such as corrugation placement or height, rear arc and trailing edge shape. Numerical simulations using the 2D laminar Navier-Stokes equations revealed that the flow accelerating over the first corrugation slope is followed by an unsteady pressure recovery, combined with vortex shedding. The latter allows the reattachment of the flow over the rear arc. Also, the drag values are directly linked to the vortices' magnitude. This parametric study shows that geometric variations which reduce the vortices' amplitude, as reduction of the rear cavity depth or the reduction of the rear arc and trailing edge curvature, will reduce the drag values. Other changes will extend the flow reattachment over the rear arc for a larger mean lift coefficients range; such as the negative deflection of the forward flat plate. These changes consequently reduce the drag values at higher mean lift coefficients. The detailed geometry study enabled the definition of a corrugated airfoil

Driver-witness electron beam acceleration in dielectric mm-scale capillaries

Science.gov (United States)

Lekomtsev, K.; Aryshev, A.; Tishchenko, A. A.; Shevelev, M.; Lyapin, A.; Boogert, S.; Karataev, P.; Terunuma, N.; Urakawa, J.

2018-05-01

We investigated a corrugated mm-scale capillary as a compact accelerating structure in the driver-witness acceleration scheme, and suggested a methodology to measure the acceleration of the witness bunch. The accelerating fields produced by the driver bunch and the energy spread of the witness bunch in a corrugated capillary and in a capillary with a constant inner radius were measured and simulated for both on-axis and off-axis beam propagation. Our simulations predicted a change in the accelerating field structure for the corrugated capillary. Also, an approximately twofold increase of the witness bunch energy gain on the first accelerating cycle was expected for both capillaries for the off-axis beam propagation. These results were confirmed in the experiment, and the maximum measured acceleration of 170 keV /m at 20 pC driver beam charge was achieved for off-axis beam propagation. The driver bunch showed an increase in energy spread of up to 11%, depending on the capillary geometry and beam propagation, with a suppression of the longitudinal energy spread in the witness bunch of up to 15%.

Report on the use of your contributions to the Pakistan earthquake relief effort

CERN Multimedia

2006-01-01

Thanks to your generosity, a total of 56 032.50 CHF was collected. On the advice of local physicists from the Qaid-i-Azam University and the National Centre for Physics in Islamabad, the money was given to the Eqbal Ahmad Foundation, where it has been used under their close supervision. The money has been used almost exclusively for building temporary shelters and, to a lesser extent, for providing emergency rations, blankets and tents. About 814 crude shelters had been constructed by 22 January. As seen in the pictures, they are wooden frames with corrugated iron sheets for the roofs and walls, with wood-board and chip-board for insulation. The wood is provided by the shelter owner, and each shelter costs about $300 for the corrugated iron sheets and the insulation. Crude as these shelters are, they are critical for saving families from freezing to death in the biting cold, rain and snow. CERN money was used to buy corrugated iron sheets for shelters, and trucks of the sheets were sent to areas in Chikar...

A hybrid nanoantenna for highly enhanced directional spontaneous emission

Energy Technology Data Exchange (ETDEWEB)

Chou, R. Yuanying; Lu, Guowei, E-mail: guowei.lu@pku.edu.cn; Shen, Hongming; He, Yingbo; Cheng, Yuqing [State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871 (China); Perriat, Pascal [MATEIS, UMR 5510 CNRS, INSA-Lyon, Université de Lyon, Villeurbanne Cedex 69621 (France); Martini, Matteo; Tillement, Olivier [ILM, UMR 5306 CNRS, Université de Lyon, Villeurbanne Cedex 69622 (France); Gong, Qihuang [State Key Laboratory for Mesoscopic Physics, Department of Physics, Peking University, Beijing 100871 (China); Collaborative Innovation Center of Quantum Matter, Beijing 100871 (China)

2014-06-28

Spontaneous emission modulated by a hybrid plasmonic nanoantenna has been investigated by employing finite-difference time-domain method. The hybrid nanoantenna configurations constituted by a gap hot-spot and of a plasmonic corrugated grating and a metal reflector sandwiching a SiO{sub 2} thin layer which appears promising for high spontaneous emission enhancement devices. Simulation assays show that the coupling between the gap-antenna and plasmonic corrugations reaches an ultra-high near-field enhancement factor in the excitation process. Moreover, concerning the emission process, the corrugations concentrate the far-field radiated power within a tiny angular volume, offering unprecedented collection efficiency. In the past decades, many kinds of optical antennas have been proposed and optimized to enhance single molecule detection. However, the excitation enhancement effect for single individual or dimmer plasmonic nanostructure is limited due to intrinsic nonradiative decay of the nanoparticle plasmon and quantum tunneling effect. The proposed hybrid configuration overwhelms the enhancement limit of single individual plasmonic structure. The findings provide an insight into spontaneous emission high enhancement through integrating the functions of different metallic nanostructures.

A hybrid nanoantenna for highly enhanced directional spontaneous emission

International Nuclear Information System (INIS)

Chou, R. Yuanying; Lu, Guowei; Shen, Hongming; He, Yingbo; Cheng, Yuqing; Perriat, Pascal; Martini, Matteo; Tillement, Olivier; Gong, Qihuang

2014-01-01

Spontaneous emission modulated by a hybrid plasmonic nanoantenna has been investigated by employing finite-difference time-domain method. The hybrid nanoantenna configurations constituted by a gap hot-spot and of a plasmonic corrugated grating and a metal reflector sandwiching a SiO 2 thin layer which appears promising for high spontaneous emission enhancement devices. Simulation assays show that the coupling between the gap-antenna and plasmonic corrugations reaches an ultra-high near-field enhancement factor in the excitation process. Moreover, concerning the emission process, the corrugations concentrate the far-field radiated power within a tiny angular volume, offering unprecedented collection efficiency. In the past decades, many kinds of optical antennas have been proposed and optimized to enhance single molecule detection. However, the excitation enhancement effect for single individual or dimmer plasmonic nanostructure is limited due to intrinsic nonradiative decay of the nanoparticle plasmon and quantum tunneling effect. The proposed hybrid configuration overwhelms the enhancement limit of single individual plasmonic structure. The findings provide an insight into spontaneous emission high enhancement through integrating the functions of different metallic nanostructures.

C2H6 scattering from LiF(0 0 1): Influence of the molecular anisotropy on rainbow scattering in both intensity and speed distributions

International Nuclear Information System (INIS)

Kondo, Takahiro; Tomii, Takashi; Yamamoto, Shigehiko

2006-01-01

We have measured the angle-resolved intensity and speed distributions of C 2 H 6 scattered from LiF(0 0 1) along the [1 0 0] azimuthal direction, the largest structural corrugation direction, to investigate the effect of the molecular anisotropy on the gas-surface interaction at the corrugated surface. While clear rainbow feature is observed in the mean energy angular distribution, no rainbow feature is detected in the intensity angular distribution. From the comparisons of the obtained results to the calculated predictions based on the simple classical theory of the ellipsoid-washboard model, the effect of the molecular anisotropy is found to play a crucial role in the rainbow feature. With an increase in the extent of the molecular anisotropy such as that of C 2 H 6 as compared with rare gas atoms, the integration of the intensity angular distributions for various molecular orientations results in the smearing of the rainbow feature on the corrugated surface. The rainbow scattering in the mean energy angular distribution, however, is not completely smeared out

Modeling and characterization of electret based vibration energy harvesters in slot-effect configuration

International Nuclear Information System (INIS)

Renaud, M; Altena, G; Elfrink, R; Goedbloed, M; De Nooijer, C; Van Schaijk, R

2015-01-01

The purpose of this article is to elaborate a model and the optimization guidelines for electret based harvesters with a specific electret/electrodes configuration, namely the slot-effect configuration. Slot-effect configured harvesters have been investigated experimentally by several research groups. A model describing their dynamic behavior has also been recently proposed in the literature. However, the simplifications used in the existing model can lead to inaccuracies and a refined analysis is elaborated in the present article. The model is compared with experimental measurements on MEMS fabricated devices with a corrugated electret. The electrodes dimensioning in the MEMS device are chosen so that the harvester behaves in a quasi-linear manner over its full range of displacement. This quasi-linearity simplifies greatly the device optimization. Indeed, the behavior of the developed electrostatic harvester is shown to be very comparable to that of piezoelectric harvesters, which are very well understood and documented. The influence of several design parameters on output power performance is investigated. As long as pull-in and breakdown voltage effects can be avoided, the electret surface potential should be maximized and the air gap minimized. We also investigate theoretically the influence of three types of electret on the generated power: planar, corrugated with partial charge coverage, and corrugated with full charge coverage. With the dimensions corresponding to our MEMS devices, the output power characteristics for the three types of electret are similar. However, it is shown that this is not always true. In some conditions, corrugated electrets with full charge coverage are detrimental for the generated power. (paper)

Preliminary simulation study of doppler reflectometry

International Nuclear Information System (INIS)

Ishii, Yuta; Hojo, Hitoshi; Yoshikawa, Masashi; Ichimura, Makoto; Haraguchi, Yusuke; Imai, Tsuyoshi; Mase, Atsushi

2010-01-01

A preliminary simulation study of Doppler reflectometry is performed. The simulations solve Maxwell's equations by a finite difference time domain (FDTD) code method in two dimensions. A moving corrugated metal target is used as a plasma cutoff layer to study the basic features of Doppler reflectometry. We examined the effects of the full width at half maximum (FWHM) of the electromagnetic waves and the corrugation depth of the metal target. Furthermore, the effect of a nonuniform plasma is studied using this FDTD analysis. The Doppler shift and velocity are compared with those obtained from FDTD analysis of a uniform plasma. (author)

Lifetime of Nano-Structured Black Silicon for Photovoltaic Applications

DEFF Research Database (Denmark)

Plakhotnyuk, Maksym; Davidsen, Rasmus Schmidt; Schmidt, Michael Stenbæk

2016-01-01

In this work, we present recent results of lifetime optimization for nano-structured black silicon and its photovoltaic applications. Black silicon nano-structures provide significant reduction of silicon surface reflection due to highly corrugated nanostructures with excellent light trapping pro......, respectively. This is promising for use of black silicon RIE nano-structuring in a solar cell process flow......In this work, we present recent results of lifetime optimization for nano-structured black silicon and its photovoltaic applications. Black silicon nano-structures provide significant reduction of silicon surface reflection due to highly corrugated nanostructures with excellent light trapping...

Spot Welding of Honeycomb Structures

Science.gov (United States)

Cohal, V.

2017-08-01

Honeycomb structures are used to prepare meals water jet cutting machines for textile. These honeycomb structures are made of stainless steel sheet thickness of 0.1-0.2 mm. Corrugated sheet metal strips are between two gears with special tooth profile. Hexagonal cells for obtaining these strips are welded points between them. Spot welding device is three electrodes in the upper part, which carries three welding points across the width of the strip of corrugated sheet metal. Spot welding device filled with press and advance mechanisms. The paper presents the values of the regime for spot welding.

Extinction of corrugated hydrogen/air flames

International Nuclear Information System (INIS)

Mizomoto, M.; Asaka, Y.; Ikai, S.; Law, C.K.

1982-01-01

Recent studies on flammability limits reveal the importance of flow nonuniformity, flame curvature, and molecular and thermal diffusivities in determining the extinguishability and the associated limits of premixed fuel/air flames. In particular, it is found that conditions which favor extinction of a lean flame may cause intensification of a rich flame. In the present study the authors have experimentally determined the extinction characteristics and limits of highly curved hydrogen/air flames as represented by the opening of bunsen flame tips. Results show that the tip opens at a constant fuel equivalence ratio of phi = 1.15, regardless of the velocity and uniformity of the upstream flow. This critical mixture concentration, while being rich, is still on the lean side of that corresponding to the maximum burning velocity (phi = 1.8), implying that for highly diffusive systems, the relevant reference concentration is that for maximum burning velocity instead of stoichiometry

Three dimensional classical theory of rainbow scattering of atoms from surfaces

International Nuclear Information System (INIS)

Pollak, Eli; Miret-Artes, Salvador

2010-01-01

Graphical abstract: In this work, we extend to three dimensions our previous stochastic classical theory on surface rainbow scattering. The stochastic phonon bath is modeled in terms of linear coupling of the phonon modes to the motion of the scattered particle. We take into account the three polarizations of the phonons. Closed formulae are derived for the angular and energy loss distributions. They are readily implemented when assuming that the vertical interaction with the surface is described by a Morse potential. The hard wall limit of the theory is derived and applied to some model corrugated potentials. We find that rainbow structure of the scattered angular distribution reflects the underlying symmetries of the surface. We also distinguish between 'normal rainbows' and 'super rainbows'. The latter occur when the two eigenvalues of the Hessian of the corrugation function vanish simultaneously. - Abstract: In this work, we extend to three dimensions our previous stochastic classical theory on surface rainbow scattering. The stochastic phonon bath is modeled in terms of linear coupling of the phonon modes to the motion of the scattered particle. We take into account the three polarizations of the phonons. Closed formulae are derived for the angular and energy loss distributions. They are readily implemented when assuming that the vertical interaction with the surface is described by a Morse potential. The hard wall limit of the theory is derived and applied to some model corrugated potentials. We find that rainbow structure of the scattered angular distribution reflects the underlying symmetries of the surface. We also distinguish between 'normal rainbows' and 'super rainbows'. The latter occur when the two eigenvalues of the Hessian of the corrugation function vanish simultaneously.

Experimental and Numerical Assessment of a New Alternative of RBS Moment Connection

International Nuclear Information System (INIS)

Mirghaderi, Rasoul; Imanpour, Ali; Keshavarzi, Farhad; Torabian, Shahab

2008-01-01

Reduced beam section (RBS) connection has been known as a famous connection for steel moment-resisting seismic frames in high-rise buildings, because of their economical advantages and seismic ductility. In the ordinary RBS connection, often portions of the beam flanges are selectively trimmed in the region adjacent to the beam-to-column connection, and beam section is weakened in the plastic hinge region; section weakening concept in the plastic hinge region of beam cause to reduction of beam plastic section modulus in this region, and force plastic hinge to occur within the reduced section.This paper presents a new alternative of RBS connection that has been used aforesaid weakening concept in it, with this difference that corrugated steel plate webs instead of beam flange cutting has been used in limited specific length near the column face. Corrugated steel plates because of their accordion effect don't have bending rigidity, then using of these plates in plastic hinge region reduces the beam plastic section modulus and plastic hinge is formed in corrugated region. For investigating the seismic behavior and performance of new RBS moment connection, experimental specimen of new RBS connection were subjected to cyclic load, and finite element analysis were executed. The result of cyclic test and numerical analysis specified that the corrugated webs improved the plastic stability and provided capability of large plastic rotation at the plastic hinge location without any appreciable buckling and brittle fractures in this region. The test observations also showed that the specimens' plastic rotations exceeded 0.04 rad without any local and global buckling. All of the analytical results for proposed connection are generally in good agreement with the test observations

Changes in pectin methyl esterase activity with different packaging materials and stages of fruit harvesting during cold storage of pear cv. Punjab beauty.

Science.gov (United States)

Kaur, Kirandeep; Dhillon, W S; Mahajan, B V C

2014-10-01

Pear cv. Punjab Beauty has become quite popular in Punjab. Excessive softening during cold storage leading to low shelf life is the major factor limiting its wider adoption. Studies were, therefore, conducted to determine the firmness and pectin methyl esterase (PME) activity at 4 harvest dates (2nd, 3rd and 4th week of July, and 1st week of August). Various packaging materials i.e. corrugated fiber board boxes and crates with high and low density polyethylene liners, corrugated fiber board boxes, crates and wooden boxes were also evaluated for their role in extending the shelf life of fruits. The enzyme activity and fruit firmness was evaluated periodically after 30, 45, 60 and 75 days of storage at 0-1 °C and 90-95 % RH. The firmness of the fruits decreased with the increase in storage intervals but the enzyme activity increased with the storage period up to 60 days and declined thereafter. Ripening-related changes in all the harvests were characterized mainly by an increase in the solubilization of pectin with a concomitant decrease in the degree of firmness. There was a continuous increase in enzyme activity with the advancement in harvesting dates and then fell sharply in the advanced ripening stages. Highest pectin methyl esterase activity was in fruits packed in crates followed by wooden boxes and corrugated fiber board boxes while the lowest was recorded in fruits packed in corrugated fiber board boxes with high density polyethylene liners. Therefore, high density polyethylene lined CFB boxes proved to be most effective in preventing the loss in firmness.

Emotion in Stories: Facial EMG Evidence for Both Mental Simulation and Moral Evaluation

Directory of Open Access Journals (Sweden)

Björn 't Hart

2018-04-01

Full Text Available Facial electromyography research shows that corrugator supercilii (“frowning muscle” activity tracks the emotional valence of linguistic stimuli. Grounded or embodied accounts of language processing take such activity to reflect the simulation or “reenactment” of emotion, as part of the retrieval of word meaning (e.g., of “furious” and/or of building a situation model (e.g., for “Mark is furious”. However, the same muscle also expresses our primary emotional evaluation of things we encounter. Language-driven affective simulation can easily be at odds with the reader's affective evaluation of what language describes (e.g., when we like Mark being furious. To examine what happens in such cases, we independently manipulated simulation valence and moral evaluative valence in short narratives. Participants first read about characters behaving in a morally laudable or objectionable fashion: this immediately led to corrugator activity reflecting positive or negative affect. Next, and critically, a positive or negative event befell these same characters. Here, the corrugator response did not track the valence of the event, but reflected both simulation and moral evaluation. This highlights the importance of unpacking coarse notions of affective meaning in language processing research into components that reflect simulation and evaluation. Our results also call for a re-evaluation of the interpretation of corrugator EMG, as well as other affect-related facial muscles and other peripheral physiological measures, as unequivocal indicators of simulation. Research should explore how such measures behave in richer and more ecologically valid language processing, such as narrative; refining our understanding of simulation within a framework of grounded language comprehension.

Radiation loss of planar surface plasmon polaritons transmission lines at microwave frequencies.

Science.gov (United States)

Xu, Zhixia; Li, Shunli; Yin, Xiaoxing; Zhao, Hongxin; Liu, Leilei

2017-07-21

Radiation loss of a typical spoof surface plasmon polaritons (SSPPs) transmission line (TL) is investigated in this paper. A 325 mm-long SSPPs TL is designed and fabricated. Simulated results show that radiation loss contributes more to transmission loss than dielectric loss and conductor loss from 2 GHz to 10 GHz. Radiation loss of the SSPPs TL could be divided into two parts, one is caused by the input mode converter, and the other is caused by the corrugated metallic strip. This paper explains mechanisms of radiation loss from different parts, designs a loaded SSPPs TL with a series of resistors to absorb electromagnetic energy on corrugated metallic strip, and then discriminates radiation loss from the input mode converter, proposes the concept of average radiation length (ARL) to evaluate radiation loss from SSPPs of finite length, and concludes that radiation loss is mainly caused by corrugated structure of finite length at low frequency band and by the input mode converter at high frequency band. To suppress radiation loss, a mixed slow wave TL based on the combination of coplanar waveguides (CPWs) and SSPPs is presented. The designed structure, sample fabrication and experimental verification are discussed.

Pool boiling performance of lithium bromide solution on enhanced tubes

International Nuclear Information System (INIS)

Sim, Yong Sub; Kim, Nae Hyun

2015-01-01

In the present study, pool boiling heat transfer coefficients of LiBr solution were obtained for smooth, corrugated, floral and low fin tubes. Test range covered saturation pressure from 7.38 kPa to 101.3 kPa, LiBr concentration from 0% to 50%. Low fin tube yielded the highest heat transfer coefficient followed by floral, corrugated and smooth tube. The sequence was the same independent of saturation pressure or LiBr concentration. For the low fin tube, the heat transfer enhancement ratio ranged from 1.34 to 2.37. Those of floral tube are 1.16 to 1.64 and those of corrugated tube are 0.90 to 1.43. The enhancement ratio decreased as LiBr concentration increased. No general trend is observed for the effect of saturation pressure. Exceptionally high heat transfer coefficient was obtained for the low fin tube in pure water. The reason may be attributed to many small bubbles at high frequency due to the existence of low fins. Boiling heat transfer correlations were developed which are applicable for saturation pressure from 7.38 kPa to 101.3 kPa and LiBr concentration from 0% to 50%.

Guiding spoof surface plasmon polaritons by infinitely thin grooved metal strip

Directory of Open Access Journals (Sweden)

Xiang Wan

2014-04-01

Full Text Available In this paper, the propagation characteristics of spoof surface plasmon polaritons (SPPs on infinitely thin corrugated metal strips are theoretically analyzed. Compared with the situations of infinitely thick lateral thickness, the infinitely thin lateral thickness leads to lower plasma frequency according to the analyses. The propagation lengths and the binding capacity of the spoof SPPs are evaluated based on the derived dispersion equation. The effects of different lateral thicknesses are also investigated. At the end, a surface wave splitter is presented using infinitely thin corrugated metal strip. Other functional planar or flexible devices can also be designed using these metal strips in microwave or terahertz regimes.

Terahertz near-field imaging using subwavelength plasmonic apertures and a quantum cascade laser source.

Science.gov (United States)

Baragwanath, Adam J; Freeman, Joshua R; Gallant, Andrew J; Zeitler, J Axel; Beere, Harvey E; Ritchie, David A; Chamberlain, J Martyn

2011-07-01

The first demonstration, to our knowledge, of near-field imaging using subwavelength plasmonic apertures with a terahertz quantum cascade laser source is presented. "Bull's-eye" apertures, featuring subwavelength circular apertures flanked by periodic annular corrugations were created using a novel fabrication method. A fivefold increase in intensity was observed for plasmonic apertures over plain apertures of the same diameter. Detailed studies of the transmitted beam profiles were undertaken for apertures with both planarized and corrugated exit facets, with the former producing spatially uniform intensity profiles and subwavelength spatial resolution. Finally, a proof-of-concept imaging experiment is presented, where an inhomogeneous pharmaceutical drug coating is investigated.

Novel types of surface acoustic wave microreflectors - Performance analysis and simulations

Science.gov (United States)

Golan, G.; Griffel, G.; Seidman, A.; Croitoru, N.

1990-06-01

Surface acoustic waves for micrograting reflectors have been characterized. Based on the perturbation theory, eight different types of structures on an acoustic waveguide were analyzed. Results of simulations of all eight types of corrugation structures were evaluated in order to find the least leaky waveguide, the most efficient reflector (with minimum necessary perturbations), and the optimal mode shape for improved performances. General design curves are presented in order to illustrate the behavior of the incident and reflected waves under a variety of structural conditions. Analytic expressions for the calculations of the mode amplitude and mode shape, and for general acoustic corrugations are derived and then the simulations results are presented.

Noncontact rack-pinion-rack device as a differential vibration sensor.

Science.gov (United States)

Miri, MirFaez; Nasiri, Mojtaba

2010-07-01

We study a nanoscale system composed of one corrugated cylinder (pinion) placed between two corrugated plates (racks). The pinion and racks have no mechanical contact, but are coupled via the lateral Casimir force-one of the most spectacular consequences of quantum fluctuations of the electromagnetic field. The noncontact design of the device could help with the noteworthy wear problem in nanoscale mechanical systems. We consider the case where both racks undergo harmonic lateral motion. We assume that the amplitude, frequency, and phase of one of the racks are known. We show that probing the pinion motion, one can determine the vibration characteristics of the other rack.

Compensation systems for low temperature applications

CERN Document Server

Skoczen, Balzej T

2004-01-01

The book is dedicated to the behaviour of ductile materials at cryogenic temperatures, structural stability issues and reliability oriented parametric optimisation of compensation systems containing the corrugated bellows. The problems of local and global stability of systems containing bellows, coupling between the low-cycle fatigue and stability as well as evolution of plastic strain fields, micro-damage and strain induced phase transformation in the corrugated shells at cryogenic temperatures are presented. As a special feature reliability oriented optimum design of compensation systems under strength, stability, fatigue and geometrical constraints is discussed. The relevant applications in the particle accelerators and cryogenic transfer lines are shown.

Improving the performance of ultrasonic horn reactor for deactivating microorganisms in water

International Nuclear Information System (INIS)

Al-juboori, R A; Yusaf, T F

2012-01-01

The research on enhancing the performance of ultrasonic reactor for the purpose of microorganisms' inactivation is still ongoing. In this work, covering the cavitation chamber bottom with a corrugated surface as a source for heterogeneous cavities has been proposed as a simple modification to improve ultrasonic deactivation for ultrasonic horn reactor. Escherichia coli ATCC 25922 was used as a model microorganism in this study. Before using the corrugated surface, the configuration of the cavitation chamber was optimized experimentally in regards to cavitation chamber diameter and the depth of ultrasonic probe tip in the suspension. The optimization of the aforementioned factors was conducted on a basis of using constant suspension volume of 50ml. The depth of the ultrasonic probe tip in the suspension was changed from 2-10mm with a step of 2mm in overall depth of the suspension of 2cm, while the diameter of the chamber was changed using five Pyrex beakers with different diameters. The study was carried out using three level of ultrasonic intensity; low (17.56), intermediate (21.49) and high (24.17) W/cm 2 . The results of the optimization showed that increasing the diameter of cavitation chamber can decrease the log reduction of E.coli significantly. However, changing the depth of ultrasound probe in the suspension within the studied range was found to have only slight effect on the log reduction of E.coli in the order of approximately 0.5-log 10 . When using the corrugated surface with optimum chamber design, the results revealed that the corrugated surface can increase the log reduction of E.coli for the applied ultrasonic intensities. This effect was more discernable with low ultrasonic intensity than intermediate and high intensities.

Heat transfer performance of condenser tubes in an MSF desalination system

International Nuclear Information System (INIS)

Galal, T.; Kalendar, A.; Al Saftawi, A.; Zedan, M.

2010-01-01

The present research examines the amount of condensed fresh water off the outer-side surface of heat exchangers in an MSF system. The quantitative modeling of condensed water on the outer surface of comparable tubes, enhanced and plain, in a simulated MSF technique is investigated. An adapted simulation design on a test-rig facility, accounting for the condenser tubing in actual industrial desalination plate-form, is used with corrugated and smooth aluminum-brass material tubes 1100mm long and 23mm bore. A single phase flow of authentic brine water that typifies real fouling is utilized to simulate the actual environmental life of a multi-stage flashing desalination system, with coolant flow velocity 0.1 m/s in the two delineated types of condenser tubing. It is demonstrated that the condensate water amount from the specified enhanced tube is about 1.22 times the condensate water amount from the smooth tube, adaptive for 140 running hours under deliberated constrains. The topic covers a comparative analysis of thermal performance. Comparing results with fresh water confirm the effect of fouling on significantly lowering the value of the overall heat transfer coefficient versus time. Fouling resistance R f is reported with the critical coolant flow speed of 0.1 m/s. Comparison between the fouling resistance for both smooth and corrugated tubes versus time is performed. The fouling thermal resistance of the corrugated tube is 0.56 of the fouling thermal resistance of the smooth tube after140 running hours of the experiment are concluded. Overall, in the case of real brine, results prove that heat performance for the corrugated tube is superior to the plain tube over the studied time period (140 hrs) for the chosen range of flow speeds

Three dimensional classical theory of rainbow scattering of atoms from surfaces

Energy Technology Data Exchange (ETDEWEB)

Pollak, Eli, E-mail: eli.pollak@weizmann.ac.il [Chemical Physics Department, Weizmann Institute of Science, 76100 Rehovoth (Israel); Miret-Artes, Salvador [Instituto de Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 123, 28006 Madrid (Spain)

2010-10-05

Graphical abstract: In this work, we extend to three dimensions our previous stochastic classical theory on surface rainbow scattering. The stochastic phonon bath is modeled in terms of linear coupling of the phonon modes to the motion of the scattered particle. We take into account the three polarizations of the phonons. Closed formulae are derived for the angular and energy loss distributions. They are readily implemented when assuming that the vertical interaction with the surface is described by a Morse potential. The hard wall limit of the theory is derived and applied to some model corrugated potentials. We find that rainbow structure of the scattered angular distribution reflects the underlying symmetries of the surface. We also distinguish between 'normal rainbows' and 'super rainbows'. The latter occur when the two eigenvalues of the Hessian of the corrugation function vanish simultaneously. - Abstract: In this work, we extend to three dimensions our previous stochastic classical theory on surface rainbow scattering. The stochastic phonon bath is modeled in terms of linear coupling of the phonon modes to the motion of the scattered particle. We take into account the three polarizations of the phonons. Closed formulae are derived for the angular and energy loss distributions. They are readily implemented when assuming that the vertical interaction with the surface is described by a Morse potential. The hard wall limit of the theory is derived and applied to some model corrugated potentials. We find that rainbow structure of the scattered angular distribution reflects the underlying symmetries of the surface. We also distinguish between 'normal rainbows' and 'super rainbows'. The latter occur when the two eigenvalues of the Hessian of the corrugation function vanish simultaneously.

Propagation and radiation characteristics of the circular electric, circular magnetic and hybrid waveguide modes

International Nuclear Information System (INIS)

Crenn, J.P.

1996-06-01

The field distributions and propagation constants of the circular electric, circular magnetic and hybrid modes of oversized waveguides are expressed, taking the effects of walls into account. The near and far field patterns are derived in the case of real wall functions. It is shown that, for very oversized waveguides, the terms containing wall functions can be ignored in the calculations, and it results that the expressions of fields and propagation constants become independent of the types of waveguides. An application to corrugated waveguides for Electron Cyclotron Resonance Heating experiments shows the variations of the radiation characteristics versus geometric parameters of the corrugations and determines the ranges of interest for these parameters. (author)

Corruption analysis and life span forecast research on sylphon bellows of nuclear-powered steam system of ship

International Nuclear Information System (INIS)

Song Chao; Chen Lisheng; Song Meicun; Wang Wei

2012-01-01

The fracture of the corrugated pipe has a dad effect to the operation of reactor which can cause the small-break LOCA. The corrosion is the key reason of the fracture. On the base of the analysis on corruption reason of the sylphon bellows and combine the characteristic of the limited sample point of it, the Grey theory was used in the assessment of corrosion life span of corrugated pipe in nuclear steam system. Through applying the GM (1, 1) model in inferring the discipline of corrosion quantity and combining traditional statistical method, the corrosion life of steam pipe was evaluated. It indicates that the model is precise, simple and the result is reliable. (authors)

Second order classical perturbation theory for atom surface scattering: Analysis of asymmetry in the angular distribution

Energy Technology Data Exchange (ETDEWEB)

Zhou, Yun, E-mail: zhou.yun.x@gmail.com; Pollak, Eli, E-mail: eli.pollak@weizmann.ac.il [Chemical Physics Department, Weizmann Institute of Science, 76100 Rehovot (Israel); Miret-Artés, Salvador, E-mail: s.miret@iff.csic.es [Instituto de Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 123, 28006 Madrid (Spain)

2014-01-14

A second order classical perturbation theory is developed and applied to elastic atom corrugated surface scattering. The resulting theory accounts for experimentally observed asymmetry in the final angular distributions. These include qualitative features, such as reduction of the asymmetry in the intensity of the rainbow peaks with increased incidence energy as well as the asymmetry in the location of the rainbow peaks with respect to the specular scattering angle. The theory is especially applicable to “soft” corrugated potentials. Expressions for the angular distribution are derived for the exponential repulsive and Morse potential models. The theory is implemented numerically to a simplified model of the scattering of an Ar atom from a LiF(100) surface.

Second order classical perturbation theory for atom surface scattering: analysis of asymmetry in the angular distribution.

Science.gov (United States)

Zhou, Yun; Pollak, Eli; Miret-Artés, Salvador

2014-01-14

A second order classical perturbation theory is developed and applied to elastic atom corrugated surface scattering. The resulting theory accounts for experimentally observed asymmetry in the final angular distributions. These include qualitative features, such as reduction of the asymmetry in the intensity of the rainbow peaks with increased incidence energy as well as the asymmetry in the location of the rainbow peaks with respect to the specular scattering angle. The theory is especially applicable to "soft" corrugated potentials. Expressions for the angular distribution are derived for the exponential repulsive and Morse potential models. The theory is implemented numerically to a simplified model of the scattering of an Ar atom from a LiF(100) surface.

Ferromagnetic and twin domains in LCMO manganites

International Nuclear Information System (INIS)

Jung, G.; Markovich, V.; Mogilyanski, D.; Beek, C. van der; Mukovskii, Y.M.

2005-01-01

Ferromagnetic and twin domains in lightly Ca-doped La 1-x Ca x MnO 3 single crystals have been visualized and investigated by means of the magneto-optical technique. Both types of domains became visible below the Curie temperature. The dominant structures seen in applied magnetic field are associated with magneto-crystalline anisotropy and twin domains. In a marked difference to the twin domains which appear only in applied magnetic field, ferromagnetic domains show up in zero applied field and are characterized by oppositely oriented spontaneous magnetization in adjacent domains. Ferromagnetic domains take form of almost periodic, corrugated strip-like structures. The corrugation of the ferromagnetic domain pattern is enforced by the underlying twin domains

Aerodynamic Improvements to Cargo Carrying Rail Cars due to Roof Modifications

Science.gov (United States)

Condie, Robert; Maynes, Daniel

2012-11-01

The aerodynamic drag associated with the transport of commodities by rail is becoming increasingly important as the cost of diesel fuel increases. We provide an assessment of the influence of the roof structure on aerodynamic performance of two dissimilar rail cars, namely automobile carrying cars and coal carrying cars. Currently, the roof material for automobile carrying rail cars is corrugated steel, with the corrugation aligned perpendicular to the direction of travel. Coal cars are currently left uncovered for loading convenience and on the return leg from the power plant are empty. Aerodynamic drag data have been obtained through wind tunnel testing on 1/29 scale models to understand the savings that may be realized by judicious modification to the tops of both these car types. For the automobile-carrying cars, testing is performed for the corrugated and smooth roof configurations. This modification alone has the potential of reducing the car drag coefficient by nominally 25%. A broader study is performed for the coal cars, with data being acquired for coal filled models, empty models, and several cover prototype configurations. The results reveal that implementation of a cover may yield reductions in the aerodynamic drag for both coal filled (nominally 7%) and empty coal cars (nominally 30%).

Interpretive Structural Modeling Of Implementation Enablers For Just In Time In ICPI

Directory of Open Access Journals (Sweden)

Nitin Upadhye

2014-12-01

Full Text Available Indian Corrugated Packaging Industries (ICPI have built up tough competition among the industries in terms of product cost, quality, product delivery, flexibility, and finally customer’s demand. As their customers, mostly OEMs are asking Just in Time deliveries, ICPI must implement JIT in their system. The term "JIT” as, it denotes a system that utilizes less, in terms of all inputs, to create the same outputs as those created by a traditional mass production system, while contributing increased varieties for the end customer. (Womack et al. 1990 "JIT" focuses on abolishing or reducing Muda (“Muda", the Japanese word for waste and on maximizing or fully utilizing activities that add value from the customer's perspective. There is lack of awareness in identifying the right enablers of JIT implementation. Therefore, this study has tried to find out the enablers from the literature review and expert’s opinions from corrugated packaging industries and developed the relationship matrix to see the driving power and dependence between them. In this study, modeling has been done in order to know the interrelationships between the enablers with the help of Interpretive Structural Modeling and Cross Impact Matrix Multiplication Applied to Classification (MICMAC analysis for the performance of Indian corrugated packaging industries.

Experimental investigation on flow patterns of RP-3 kerosene under sub-critical and supercritical pressures

Science.gov (United States)

Wang, Ning; Zhou, Jin; Pan, Yu; Wang, Hui

2014-02-01

Active cooling with endothermic hydrocarbon fuel is proved to be one of the most promising approaches to solve the thermal problem for hypersonic aircraft such as scramjet. The flow patterns of two-phase flow inside the cooling channels have a great influence on the heat transfer characteristics. In this study, phase transition processes of RP-3 kerosene flowing inside a square quartz-glass tube were experimentally investigated. Three distinct phase transition phenomena (liquid-gas two phase flow under sub-critical pressures, critical opalescence under critical pressure, and corrugation under supercritical pressures) were identified. The conventional flow patterns of liquid-gas two phase flow, namely bubble flow, slug flow, churn flow and annular flow are observed under sub-critical pressures. Dense bubble flow and dispersed flow are recognized when pressure is increased towards the critical pressure whilst slug flow, churn flow and annular flow disappear. Under critical pressure, the opalescence phenomenon is observed. Under supercritical pressures, no conventional phase transition characteristics, such as bubbles are observed. But some kind of corrugation appears when RP-3 transfers from liquid to supercritical. The refraction index variation caused by sharp density gradient near the critical temperature is thought to be responsible for this corrugation.

The not-so-bitter pill: Effects of combined oral contraceptives on peripheral physiological indicators of emotional reactivity.

Science.gov (United States)

Armbruster, Diana; Kirschbaum, Clemens; Strobel, Alexander

2017-08-01

Combined oral contraceptives (COC) are used by millions of women worldwide. Although findings are not entirely consistent, COC have been found to impact on brain function and, thus, to modulate affective processes. Here, we investigated electro-physiological responses to emotional stimuli in free cycling women in both the early follicular and late luteal phase as well as in COC users. Skin conductance response (SCR), startle reflex, corrugator and zygomaticus activity were assessed. COC users showed reduced overall startle magnitude and SCR amplitude, but heightened overall zygomaticus activity, although effect sizes were small. Thus, COC users displayed reduced physiological reactions indicating negative affect and enhanced physiological responses signifying positive affect. In free cycling women, endogenous 17β-estradiol levels were associated with fear potentiated startle in both cycle phases as well as with SCR and zygomaticus activity during the follicular phase. Testosterone was associated with corrugator and zygomaticus activity during the luteal phase, while progesterone levels correlated with corrugator activity in the follicular phase. To the contrary, in COC users, endogenous hormones were not associated with electro-physiological measures. The results further underscore the importance of considering COC use in psychophysiological studies on emotional processing. Copyright © 2017 Elsevier Inc. All rights reserved.

CFD Analysis on the Periodic Element of a Printed Circuit Heat Exchanger

International Nuclear Information System (INIS)

Tak, Nam-il; Kim, Min-Hwan; Lee, Won-Jae

2007-01-01

A typical printed circuit heat exchanger (PCHE) is composed of a large number of flow channels with lateral corrugations. In an effort to investigate fundamental thermo-fluid characteristics of a PCHE with corrugated channels, computational fluid dynamics (CFD) analyses were previously made in. One pair of flow channels (i.e., cold and hot channels) with the entire flow path was considered for the computational domain in the previous studies. Although only one pair of flow channels with coarse meshes was used, computational loads were found to be very high to simulate the entire flow path of the PCHE. Fortunately a recent study has shown that a simplified CFD methodology with a stream wise periodic assumption (called periodic CFD analysis) is feasible for a CFD evaluation of the thermo-fluid performance of compact heat exchangers. Since the periodic CFD analysis focuses on the periodic element of a flow channel, the required computing resources are dramatically reduced. In the present paper, the periodic CFD analysis has been applied to the periodic element of the PCHE. The results are compared with those of the full elements which have an entire flow path. Based on the periodic approach the effects of the corrugation parameters on the thermo-fluid performance of the PCHE are investigated

New receiving line for the remote-steering antenna of the 140 GHz CTS diagnostics in the FTU Tokamak

Science.gov (United States)

D'Arcangelo, O.; Bin, W.; Bruschi, A.; Cappelli, M.; Fanale, F.; Gittini, G.; Pallotta, F.; Rocchi, G.; Tudisco, O.; Garavaglia, S.; Granucci, G.; Moro, A.; Tuccillo, A. A.

2018-01-01

A new receiving antenna for collecting signals of the Collective Thomson Scattering (CTS) diagnostics in FTU Tokamak has been recently installed. The squared corrugated section and the precisely defined length make it possible to receive from different directions by remotely steering the receiving mirrors. This type of Remote-Steering (RS) antennas, being studied on FTU for the DEMO Electron Cyclotron Heating (ECH) system launch, is already installed on the W7- X stellarator and will be tested in the next campaign. The transmission of the signal from the antenna in the tokamak hall to the CTS diagnostics hall will be mainly realized by means of oversized circular corrugated waveguides carrying the hybrid HE11 (quasi-gaussian) waveguide mode, with inclusion of a special smooth-waveguide section and a short run of reduced-size square-corrugated waveguide through the tokamak bio-shield. The coupling between different waveguide types is made with ellipsoidal focusing mirrors, using quasi-optical matching formulas between the gaussian-shaped beams in input and output to the waveguides. In this work, after a complete study of feasibility of the overall line, a design for the receiving line will be proposed, in order to realize an executive layout to be used as a guideline for the commissioning phase.

Determination of electromagnetic modes in oversized corrugated waveguides on the electron cyclotron resonance heating installation at the tokamak Tore Supra; Determination de modes electromagnetiques de guides d'ondes corrugues surdimensionnes sur l'installation de chauffage des electrons de tokamak Tore Supra

Energy Technology Data Exchange (ETDEWEB)

Courtois, L

2001-03-09

Electron cyclotron resonance heating (ECRH) in the Tore Supra tokamak constitutes an important step in the research aimed at obtaining thermonuclear fusion reactions. Electron heating is achieved by transmitting an electromagnetic wave from the oscillators (gyrotrons) to the plasma via the fundamental mode, propagating in oversized corrugated waveguides. Maximizing the proportion of the gyrotron power coupled to the fundamental waveguide mode is essential for the good functioning of the transmission line and for maximizing the effect on the plasma. This thesis gives all necessary tools for finding the proportion of the fundamental mode and all other modes present in passive components and at the output of the gyrotron as installed in the Tore Supra ECRH plant. This characterisation is based on obtaining amplitude and phase diagrams of the electric field on a plane transverse to the propagation axis. The most difficult part of obtaining these diagrams is measuring the phase which, despite the very short wavelength, is measured directly at low power levels. At high power levels the phase is numerically reconstructed from amplitude measurements for gyrotron characterisation. A complete theoretical study of the phase reconstruction code is given including its validation with theoretical diagrams. This study allows the realisation of a modal characterisation unit electromagnetic for measurement of radiated beams and usable in each part of the ECRH installation. At the end, the complete modal characterisation is given at low level for a mode converter and also at high level for the first series gyrotron installed at TORE SUPRA. (author)

Flattening and manipulation of the electronic structure of h-BN/Rh(111) nanomesh upon Sn intercalation

Science.gov (United States)

Sugiyama, Yuya; Bernard, Carlo; Okuyama, Yuma; Ideta, Shin-ichiro; Tanaka, Kiyohisa; Greber, Thomas; Hirahara, Toru

2018-06-01

We have deposited Sn on corrugated hexagonal boron nitride (h-BN) nanomeshs formed on Rh(111) and found that Sn atoms are intercalated between h-BN and Rh, flattening the h-BN. Our reflection high-energy electron diffraction (RHEED) analysis showed that the average in-plane lattice constant of h-BN increases due to the loss of the corrugation. Furthermore, electronic structure measurements based on angle-resolved photoemission spectroscopy (ARPES) showed that the h-BN π band width increases significantly while the σ band width does not change as much. These behaviors were partly different from previous reports on the intercalation of h-BN/Rh system. Our results offer a novel, simple method to control the electronic structure of h-BN.

Kualitas udara disektor industri karung plastik

Directory of Open Access Journals (Sweden)

Arum Yuniari

1998-06-01

Full Text Available Air pollution is generated by air pollutant in production. Raw materials used in the production of plastic corrugated sack are Polyethylene and Polypropylene. Polyethylene and Polypropylene yars are knitted to be various plastic knits such as plastic corrugated sacks. The result of this study shows that concentration of dust particles in processing area is 30 – 34 ugr/m3, and in finishing area is 38,6- 972 ugr/m3. The other gases such as Ox, SO2, H2S and NH3 are still low. The overage concentration of dust particle in ambient air is about 38,6 – 380 ugr/m3. However for parameter of Ox, SO2, H2S and NH3 seems stile low

High-power microwave transmission and mode conversion program. Progress report, June 15, 1993--June 15, 1994

International Nuclear Information System (INIS)

Vernon, R.J.; Lorbeck, J.A.

1994-06-01

This report briefly discusses the following topics: (1) Quasi-optical converter design for Varian gyrotron SN 4.1; (2) Quasi-optical converter cold-test measurement; (3) Modification of geometrical-optics synthesized surfaces; (4)Diffraction synthesis; (5) Tapered dimpled launcher; (6) Work on Vlasov converter system for Varian gyrotron SN 4.1R; (7) Analysis of gyrotron spurious modes; (8) MIT code benchmarking; (9) Development of low-power efficiency test for Vlasov converters; (10) Investigation of optimal beam waist size and mode content for injection into a circular and rectangular corrugated waveguides; (11) The effect of corrugations on reduction of the fields at the wall of waveguides; (12) Shipping of a microwave scanner to Varian and further microwave scanner development; and (13) Code transferred to Varian

Observation of seasonal effects in traveling ionospheric disturbances by the directional deviation technique

International Nuclear Information System (INIS)

Walton, E.K.; Bailey, A.D.

1976-01-01

An experiment was performed during the years 1962 through 1964 in which direction of arrival data were collected on pulse signals received over a 450 km east-west path. In order to determine the effect that traveling ionospheric disturbances (TIDs) had on these data, a ''corrugation'' model was proposed. The corrugation model assumes that TIDs can be treated as if they were moving cylindrical sinusoidal perturbations on the ionospheric reflecting surface. Lateral deviations in the experimental data of the type predicted by this model were found to be quite common. Variations in the detected TIDs as a function of time of year were found to be consistent with the ''seasonal effect'' studied by Munro in 1958, Jones 1969, and Davies and Jones in 1971

Treatment Outcomes of Auricular Hematoma Using Corrugated ...

African Journals Online (AJOL)

It poses a challenge to the otolaryngologist in the developing world due to its high rate of recurrence, and lack of appropriate materials for use as stitch dressing. The diagnosis of auricular hematoma is generally straightforward. The collected blood or serum causes a loss of normal contour on the lateral surface of the auricle ...

Corrugated grating on organic multilayer Bragg reflector

Science.gov (United States)

Jaquet, Sylvain; Scharf, Toralf; Herzig, Hans Peter

2007-08-01

Polymeric multilayer Bragg structures are combined with diffractive gratings to produce artificial visual color effects. A particular effect is expected due to the angular reflection dependence of the multilayer Bragg structure and the dispersion caused by the grating. The combined effects can also be used to design particular filter functions and various resonant structures. The multilayer Bragg structure is fabricated by spin-coating of two different low-cost polymer materials in solution on a cleaned glass substrate. These polymers have a refractive index difference of about 0.15 and permit multilayer coatings without interlayer problems. Master gratings of different periods are realized by laser beam interference and replicated gratings are superimposed on the multilayer structure by soft embossing in a UV curing glue. The fabrication process requires only polymer materials. The obtained devices are stable and robust. Angular dependent reflection spectrums for the visible are measured. These results show that it is possible to obtain unexpected reflection effects. A rich variety of color spectra can be generated, which is not possible with a single grating. This can be explained by the coupling of transmission of grating orders and the Bragg reflection band. A simple model permits to explain some of the spectral vs angular dependence of reflected light.

Hyperbolic Metamaterials with Complex Geometry

DEFF Research Database (Denmark)

Lavrinenko, Andrei; Andryieuski, Andrei; Zhukovsky, Sergei

2016-01-01

We investigate new geometries of hyperbolic metamaterialssuch as highly corrugated structures, nanoparticle monolayer assemblies, super-structured or vertically arranged multilayersand nanopillars. All structures retain basic propertiesof hyperbolic metamaterials, but have functionality improved...

Journal of Chemical Sciences | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Chemical Sciences; Volume 121; Issue 5 ... self-affine fractals: Comparative study of statistically corrugated and isotropic roughness ... Theory of coherent molecule to surface electron injection: An analytical model.

Non-Planar Nanotube and Wavy Architecture Based Ultra-High Performance Field Effect Transistors

KAUST Repository

Hanna, Amir

2016-01-01

This dissertation also introduces a novel thin-film-transistors architecture that is named the Wavy Channel (WC) architecture, which allows for extending device width by integrating vertical fin-like substrate corrugations giving

Meshed doped silicon photonic crystals for manipulating near-field thermal radiation

Science.gov (United States)

Elzouka, Mahmoud; Ndao, Sidy

2018-01-01

The ability to control and manipulate heat flow is of great interest to thermal management and thermal logic and memory devices. Particularly, near-field thermal radiation presents a unique opportunity to enhance heat transfer while being able to tailor its characteristics (e.g., spectral selectivity). However, achieving nanometric gaps, necessary for near-field, has been and remains a formidable challenge. Here, we demonstrate significant enhancement of the near-field heat transfer through meshed photonic crystals with separation gaps above 0.5 μm. Using a first-principle method, we investigate the meshed photonic structures numerically via finite-difference time-domain technique (FDTD) along with the Langevin approach. Results for doped-silicon meshed structures show significant enhancement in heat transfer; 26 times over the non-meshed corrugated structures. This is especially important for thermal management and thermal rectification applications. The results also support the premise that thermal radiation at micro scale is a bulk (rather than a surface) phenomenon; the increase in heat transfer between two meshed-corrugated surfaces compared to the flat surface (8.2) wasn't proportional to the increase in the surface area due to the corrugations (9). Results were further validated through good agreements between the resonant modes predicted from the dispersion relation (calculated using a finite-element method), and transmission factors (calculated from FDTD).

Components for transmission of very high power mm-waves (200 kW at 28, 70 and 140 GHz) in overmoded circular waveguides

International Nuclear Information System (INIS)

Thumm, M.; Erckmann, V.; Kasparek, W.; Kumric, H.; Mueller, G.A.; Schueller, P.G.; Wilhelm, R.

1986-03-01

Optimized overmoded circular waveguide components of transmission lines developed for high-power (200 kW) millimeter wave applications at 28, 70 and 140 GHz, as e.g. electron cyclotron resonance heating (ECRH) of plasmas for thermonuclear fusion research with gyrotrons, are described. Axisymmetric, narrow, pencil-like beams with well-defined polarization (HE11 hybrid mode) are used at open-ended corrugated waveguide antennas. The HE11 mode is generated from TEsub(On) gyrotron modes by the two multi-step mode conversion processes: (1) TEsub(On)->TE 01 ->TE 11 ->HE 11 or (2) TEsub(On)->TE 01 ->TM 11 ->HE 11 . This paper reports computer-aided analyses and measurements on mode transducer systems of the first type at 28 and 70 GHz and of the second type at 140 GHz. In all cases the overall efficiency of the complete mode conversion sequence in the desired mode is approximately (92-95)%. The mode purity in the transmission lines is conserved by using corrugated gradual waveguide bends with optimized curvature distribution and diameter tapers with non-linear contours. Highly efficient corrugated-wall mode selective filters decouple the different waveguide sections. Mode content and reflected power are determined by a novel device (k-spectrometer). Absolute power calibration is done with newly developed calorimetric loads using an organic absorbing fluid. (orig.) [de

Establishing a design procedure for buried steel-reinforced high-density polyethylene pipes : a field study, [technical summary].

Science.gov (United States)

2015-11-01

Several national standards and specification have been developed for design, installation, : and materials for precast concrete pipe, corrugated metal pipe, and HDPE pipes. However, : no national accepted installation standard or design method is ava...

Localized surface plate modes via flexural Mie resonances

KAUST Repository

Farhat, M.

2017-05-11

Surface-plasmon polaritons are naturally generated upon excitation of metals with high-frequency electromagnetic waves. However, the concept of spoof plasmons has made it possible to generate plasmoniclike effects in microwave electrodynamics, magnetics, and even acoustics. Similarly, in this paper, the concept of localized surface plate modes (SPMs) is introduced. It is demonstrated that SPMs can be generated on a two-dimensional (clamped or stress-free) cylindrical surface with subwavelength corrugations, which resides on a thin elastic plate, under excitation by an incident flexural plane wave. Numerical characterization of this corrugated rigid structure shows that it is elastically equivalent to a cylindrical scatterer with dispersive but uniformly negative flexural rigidity. This, indeed, suggests that plasmoniclike elastic materials can be engineered with potential applications in various areas including earthquake sensing and elastic imaging and cloaking.

Localized surface plate modes via flexural Mie resonances

KAUST Repository

Farhat, M.; Chen, P. -Y.; Guenneau, S.; Salama, Khaled N.; Bagci, Hakan

2017-01-01

Surface-plasmon polaritons are naturally generated upon excitation of metals with high-frequency electromagnetic waves. However, the concept of spoof plasmons has made it possible to generate plasmoniclike effects in microwave electrodynamics, magnetics, and even acoustics. Similarly, in this paper, the concept of localized surface plate modes (SPMs) is introduced. It is demonstrated that SPMs can be generated on a two-dimensional (clamped or stress-free) cylindrical surface with subwavelength corrugations, which resides on a thin elastic plate, under excitation by an incident flexural plane wave. Numerical characterization of this corrugated rigid structure shows that it is elastically equivalent to a cylindrical scatterer with dispersive but uniformly negative flexural rigidity. This, indeed, suggests that plasmoniclike elastic materials can be engineered with potential applications in various areas including earthquake sensing and elastic imaging and cloaking.

Efficient modeling of metallic interconnects for thermo-mechanical simulation of SOFC stacks: homogenized behaviors and effect of contact

DEFF Research Database (Denmark)

Tadesse Molla, Tesfaye; Kwok, Kawai; Frandsen, Henrik Lund

2016-01-01

temperature, deformations involving the elastic, creep as well as effect of changes in the geometry due to contact should be accounted for. The constitutive law can be applied using 3D modeling, but for simple presentation of the theory, 2D plane strain formulation is used to model the corrugated metallic......Currently thermo-mechanical analysis of the entire solid oxide fuel cell (SOFC) stack at operational conditions is computationally challenging if the geometry of metallic interconnects is considered explicitly. This is particularly the case when creep deformations in the interconnect are considered...... model to calculate the homogenized mechanical response of corrugated metallic interconnects at high temperatures.Thereafter, a constitutive law for the homogenized structure (effective material law) is developed. In order to properly describe the mechanical behavior of the interconnect at high...

Effect of cellulase treatment of long fiber fraction on strength ...

African Journals Online (AJOL)

fiber and unbeaten short-fiber fractions. The obtained test results have indicate that the application of enzyme on appropriate fiber fraction have positive effects on the strength properties of the corrugated medium. The short span compression ...

Analysis of Hydrogen/Air Turbulent Premixed Flames at Different Karlovitz Numbers Using Computational Singular Perturbation

KAUST Repository

Manias, Dimitrios; Tingas, Alexandros-Efstathios; Hernandez Perez, Francisco E.; Im, Hong G.; Galassi, Riccardo Malpica; Ciottoli, Pietro Paolo; Valorani, Mauro

2018-01-01

The dynamics and structure of two turbulent H2/air premixed flames, representative of the corrugated flamelet (Case 1) and thin reaction zone (Case 2) regimes, are analyzed and compared, using the computational singular perturbation (CSP) tools

Physical origin of photonic energy gaps in the propagation of surface plasmons on gratings

International Nuclear Information System (INIS)

Barnes, W.L.; Preist, T.W.; Kitson, S.C.; Sambles, J.R.

1996-01-01

We present an analytic model to describe the existence of photonic energy gaps in the propagation of surface plasmon polaritons on corrugated surfaces. We concentrate on elucidating the physical origin of the band gap, and accordingly we place strong emphasis on the physical reasoning and assumptions that we use. Our model is designed to give direct access to expressions for the electromagnetic field and surface charge distributions associated with modes at the band edges, thus allowing their physical character to be easily appreciated. Having established why a band gap occurs we then find expressions for the central position and width of the gap. We compare the results of our model for the gap width with those already in the literature, and find excellent agreement. Our results for the central position of the gap, notably the prediction that it should fall as the corrugation amplitude rises, contradicts one prediction made in the literature. We also reexamine the comparisons made in the literature between experiment and theory for the gap width, and find them inadequate because the theories have been compared to inappropriate experimental data. Consequently we present our own recent experimental data, enabling us to validate our theoretical results, in particular confirming our prediction that the central position of the gap falls as the corrugation amplitude is increased. The limitations of our model are discussed, as well as possible extensions and areas for future research. copyright 1996 The American Physical Society

Corrosion of Spiral Rib Aluminized Pipe : [Summary

Science.gov (United States)

2012-01-01

Large diameter, corrugated steel pipes are a common sight in the culverts that run alongside many Florida roads. Spiral-ribbed aluminized pipe (SRAP) has been widely specified by the Florida Department of Transportation (FDOT) for runoff drainage. Th...

Corrosion of Spiral Rib Aluminized Pipe

Science.gov (United States)

2012-08-01

Large diameter, corrugated steel pipes are a common sight in the culverts that run alongside many Florida roads. Spiral-ribbed aluminized pipe (SRAP) has been widely specified by the Florida Department of Transportation (FDOT) for runoff drainage. Th...

Experimental results for an experimental condensation heat exchanger with a spiral minichanel tube. Comparison to numerical imulations

Directory of Open Access Journals (Sweden)

Hrubý J.

2013-04-01

Full Text Available The paper describes new results for an experimental heat exchanger equipped with a single corrugated capillary tube, basic information about the measurements and the experimental setup. Some of the results were compared with numerical simulations.

Safety grade pressurizer heater power supply connector assembly

International Nuclear Information System (INIS)

Burnett, J.M.; Daftari, R.M.; Reyns, R.M.

1987-01-01

This patent describes a pressurizer heater power supply connector assembly for attaching a power cable to an electric heater within a pressurizer of a pressurized water nuclear reactor system, the electric heater having pin contacts. The assembly comprises: a pin-socket type connector including a tubular body having a first open end carrying a pin-socket contact member and an insert intermediate a shell and the pin-socket contact member, the contact member having socket means for electrically receiving and contacting the pin contacts, and a second open end; a flexible sealed conduit including a flexible corrugated tube having one end connected to the second open end of the pin-socket type connector, and another end; and a shop splice assembly including a header adapter and a hose clamp interconnected between the header adapter and another end of the flexible corrugated tube

Optimization of charge-carrier generation in amorphous-silicon thin-film tandem solar cell backed by two-dimensional metallic surface-relief grating

Science.gov (United States)

Civiletti, Benjamin J.; Anderson, Tom H.; Ahmad, Faiz; Monk, Peter B.; Lakhtakia, Akhlesh

2017-08-01

The rigorous coupled-wave approach was implemented in a three-dimensional setting to calculate the chargecarrier-generation rate in a thin-film solar cell with multiple amorphous-silicon p-i-n junctions. The solar cell comprised a front antireflection window; three electrically isolated p-i-n junctions in tandem; and a periodically corrugated silver back-reflector with hillock-shaped corrugations arranged on a hexagonal lattice. The differential evolution algorithm (DEA) was used to maximize the charge-carrier-generation rate over a set of selected optical and electrical parameters. This optimization exercise minimized the bandgap of the topmost i-layer but all other parameters turned out to be uninfluential. More importantly, the exercise led to a configuration that would very likely render the solar cell inefficient. Therefore, another optimization exercise was conducted to maximize power density. The resulting configuration was optimal over all parameters.

Modeling the thermal behavior of fluid flow inside channels using an artificial locally linear neuro-fuzzy approach

Directory of Open Access Journals (Sweden)

Azadeh Hashemian

2008-06-01

Full Text Available Enhanced surface heat exchangers are commonly used all worldwide. If applicable, due to their complicated geometry, simulating corrugated plate heat exchangers is a time-consuming process. In the present study, first we simulate the heat transfer in a sharp V-shape corrugation cell with constant temperature walls; then, we use a Locally Linear Neuro-Fuzzy method based on a radial basis function (RBFs to model the temperature field in the whole channel. New approach is developed to deal with fast computational and low memory resources that can be used with the largest available data sets. The purpose of the research is to reveal the advantages of proposed Neuro-Fuzzy model as a powerful modeling system designed for predicting and to make a fair comparison between it and the successful FLUENT simulated approaches in its best structures.

Remote Control System of the TJ-II Microwave Transmission Lines Mirrors

International Nuclear Information System (INIS)

Lopez Sanchez, A.; Fernandez, A.; Cappa, A.; Gama, J. de la; Olivares, J.; Garcia, R.; Chamorro, M.

2007-01-01

The ECRH system of the TJ-II stellarator has two gyrotrons, which deliver a maximum power of 300 kW each at a frequency of 53.2 GHz. Another 28 GHz gyrotron will be used to heat the plasma by electron Bernstein waves (EBWH). The microwave power is transmitted from the gyrotrons to the vacuum chamber by two quasi-optical transmission lines for ECRH and a corrugated waveguide for EBWH. All transmission lines have an internal movable mirror inside the vacuum chamber to focus the beam and to be able to change the launching angle. The control of the beam polarization is very important and the lines have two corrugated mirrors, which actuate as polarizers. In this report the control system of the position of these three internal mirrors and the polarizers of the EBWH transmission line is described. (Author) 20 refs

Remote Control System of the TJ-II Microwave Transmission Lines Mirrors; Sistema de Control Remoto de los Espejos de las Lineas de Transmision de Microondas del TJ-II

Energy Technology Data Exchange (ETDEWEB)

Lopez Sanchez, A.; Fernandez, A.; Cappa, A.; Gama, J. de la; Olivares, J.; Garcia, R.; Chamorro, M.

2007-09-27

The ECRH system of the TJ-II stellarator has two gyrotrons, which deliver a maximum power of 300 kW each at a frequency of 53.2 GHz. Another 28 GHz gyrotron will be used to heat the plasma by electron Bernstein waves (EBWH). The microwave power is transmitted from the gyrotrons to the vacuum chamber by two quasi-optical transmission lines for ECRH and a corrugated waveguide for EBWH. All transmission lines have an internal movable mirror inside the vacuum chamber to focus the beam and to be able to change the launching angle. The control of the beam polarization is very important and the lines have two corrugated mirrors, which actuate as polarizers. In this report the control system of the position of these three internal mirrors and the polarizers of the EBWH transmission line is described. (Author) 20 refs.

Millimeter-wave FEL-oscillator with a new type Bragg resonator: advantages in efficiency and selectivity

CERN Document Server

Ginzburg, N S; Kaminsky, A K; Peskov, N Yu; Sedykh, S N; Sergeev, A P

2000-01-01

An FEL-oscillator with a new type of Bragg resonator was realized on the basis of linac LIU-3000 (JINR, Dubna) (0.8 MeV/200 A/200 ns). This resonator consists of two corrugated waveguide sections having a step of phase pi between the corrugations at the point of connection. The selective properties of a resonator of this type are significantly improved in comparison with a traditional two-mirror Bragg resonator. The output power was about 50 MW at a frequency of 30.7 GHz with the optimal parameters of the resonator, which corresponds to the efficiency of 35%, which is the highest for millimeter wavelength FEL. Radiation at the fundamental mode and the two side modes with the frequencies coincided to the 'cold' microwave testing was separately observed depending on the magnetic fields of the wiggler and solenoid.

Thermal-hydraulic performance of the finned surface of a compact heat exchanger

International Nuclear Information System (INIS)

Errasti Cabrera, Michel

2015-01-01

In this work the thermal-hydraulic behavior of the finned surface of a compact heat exchanger is obtained in tube-fin configuration corrugated (wavy). Through numerical simulation are determined average values ​​of intensification of heat transfer and pressure loss in the inter-channel finned. The objective is to characterize the surface to use as a reference, to make comparisons with other heat exchange surfaces enhanced using traditional techniques combined with more current, such as vortex generators. The study is conducted in laminar flow, with Reynolds numbers below 1000. In the working model compact exchanger tubes and corrugated fins (wavy) heat is described, and the results of the coefficient of overall heat transfer and the pressure drop are explained from the local characteristics of the velocity field and temperature inside the heat exchanger. (Full text)

Simulation of photonic waveguides with deterministic aperiodic nanostructures for biosensing

DEFF Research Database (Denmark)

Neustock, Lars Thorben; Paulsen, Moritz; Jahns, Sabrina

2016-01-01

Photonic waveguides with deterministic aperiodic corrugations offer rich spectral characteristics under surface-normal illumination. The finite-element method (FEM), the finite-difference time-domain (FDTD) method and a rigorous coupled wave algorithm (RCWA) are compared for computing the near...

Efficient simulation of flow and heat transfer in arbitrarily shaped pipes

NARCIS (Netherlands)

Rosen Esquivel, P.I.

2012-01-01

The transport of fluids through pipes is a very common application. Corrugated pipes have characteristics such as local stiffness and flexibility that makes them convenient in several application areas such as offshore LNG (Liquefied Natural Gas) transfer, cryogenic engineering, domestic appliances,

A prospective, controlled study of prophylactic drainage after colonic anastomoses

DEFF Research Database (Denmark)

Hoffmann, J.; Shokouh-Amiri, M H; Damm, P

1987-01-01

A prospective, randomized, controlled trial was designed to study the influence of a corrugated latex drain on anastomotic integrity, wound infection, and respiratory complications after elective colonic resections above the pelvic peritoneum. Sixty patients entered the trial; 28 were drained...

Lifetime of ALD Al₂O₃ Passivated Black Silicon Nanostructured for Photovoltaic Applications

DEFF Research Database (Denmark)

Plakhotnyuk, Maksym; Davidsen, Rasmus Schmidt; Schmidt, Michael Stenbæk

Black silicon nano-structures provide significant reduction of silicon surface reflection due to highly corrugated nano-structures with excellent light trapping properties. However, most recent RIE techniques for black silicon nano-structuring have one very important limitation for PV applications...

Commissioning of inline ECE system within waveguide based ECRH transmission systems on ASDEX upgrade

NARCIS (Netherlands)

Bongers, W.A.; Kasparek, W.; Doelman, N. J.; Braber, R. van den; Brand, H. van den; Meo, F.; Baar, M.R. de; Amerongen, F.J.; Donné, A.J.H.; Elzendoorn, B.S.Q.; Erckmann, V.; Goede, A.P.H.; Giannone, L.; Grünwald, G.; Hollman, F.; Kaas, G.; Krijger, B.; Michel, G.; Lubyako, L.; Monaco, F.; Noke, F.; Petelin, M.; Plaum, B.; Purps, F.; Pierik, J.G.W. ten; Schüller, C.; Slob, J.W.; Stober, J.K.; Schütz, H.; Wagner, D.; Westerhof, E.; Ronden, D.M.S.

2012-01-01

A CW capable inline electron cyclotron emission (ECE) separation system for feedback control, featuring oversized corrugated waveguides, is commissioned on ASDEX upgrade (AUG). The system is based on a combination of a polarization independent, non-resonant, Mach-Zehnder diplexer equipped with

Simulations of water nano-confined between corrugated planes

Science.gov (United States)

Zubeltzu, Jon; Artacho, Emilio

2017-11-01

Water confined to nanoscale widths in two dimensions between ideal planar walls has been the subject of ample study, aiming at understanding the intrinsic response of water to confinement, avoiding the consideration of the chemistry of actual confining materials. In this work, we study the response of such nanoconfined water to the imposition of a periodicity in the confinement by means of computer simulations, both using empirical potentials and from first-principles. For that we propose a periodic confining potential emulating the atomistic oscillation of the confining walls, which allows varying the lattice parameter and amplitude of the oscillation. We do it for a triangular lattice, with several values of the lattice parameter: one which is ideal for commensuration with layers of Ih ice and other values that would correspond to more realistic substrates. For the former, the phase diagram shows an overall rise of the melting temperature. The liquid maintains a bi-layer triangular structure, however, despite the fact that it is not favoured by the external periodicity. The first-principles liquid is significantly affected by the modulation in its layering and stacking even at relatively small amplitudes of the confinement modulation. Beyond some critical modulation amplitude, the hexatic phase present in flat confinement is replaced by a trilayer crystalline phase unlike any of the phases encountered for flat confinement. For more realistic lattice parameters, the liquid does not display higher tendency to freeze, but it clearly shows inhomogeneous behaviour as the strength of the rugosity increases. In spite of this expected inhomogeneity, the structural and dynamical response of the liquid is surprisingly insensitive to the external modulation. Although the first-principles calculations give a more triangular liquid than the one observed with empirical potentials (TIP4P/2005), both agree remarkably well for the main conclusions of the study.

Commissioning of inline ECE system within waveguide based ECRH transmission systems on ASDEX upgrade

DEFF Research Database (Denmark)

Bongers, W. A.; Kasparek, W.; Doelman, N.

2012-01-01

A CW capable inline electron cyclotron emission (ECE) separation system for feedback control, featuring oversized corrugated waveguides, is commissioned on ASDEX upgrade (AUG). The system is based on a combination of a polarization independent, non-resonant, Mach-Zehnder diplexer equipped with di...

Microstructured hollow fibers for ultrafiltration

NARCIS (Netherlands)

Culfaz, Pmar Zeynep; Culfaz, P.Z.; Rolevink, Hendrikus H.M.; van Rijn, C.J.M.; Lammertink, Rob G.H.; Wessling, Matthias

2010-01-01

Hollow fiber ultrafiltration membranes with a corrugated outer microstructure were prepared from a PES/PVP blend. The effect of spinning parameters such as air gap, take-up speed, polymer dope viscosity and coagulation value on the microstructure and membrane characteristics was investigated. Fibers

What makes an art expert? Emotion and evaluation in art appreciation.

Science.gov (United States)

Leder, Helmut; Gerger, Gernot; Brieber, David; Schwarz, Norbert

2014-01-01

Why do some people like negative, or even disgusting and provocative artworks? Art expertise, believed to influence the interplay among cognitive and emotional processing underlying aesthetic experience, could be the answer. We studied how art expertise modulates the effect of positive-and negative-valenced artworks on aesthetic and emotional responses, measured with self-reports and facial electromyography (EMG). Unsurprisingly, emotionally-valenced art evoked coherent valence as well as corrugator supercilii and zygamoticus major activations. However, compared to non-experts, experts showed attenuated reactions, with less extreme valence ratings and corrugator supercilii activations and they liked negative art more. This pattern was also observed for a control set of International Affective Picture System (IAPS) pictures suggesting that art experts show general processing differences for visual stimuli. Thus, much in line with the Kantian notion that an aesthetic stance is emotionally distanced, art experts exhibited a distinct pattern of attenuated emotional responses.

Measurement and analysis of active synchrotron mirrors under operating conditions

Science.gov (United States)

Sutter, John P.; Alcock, Simon G.; Sawhney, Kawal

2013-05-01

At the Diamond Light Source, in situ slope error measurements using the pencil-beam method have enabled X-ray mirror surfaces to be examined in their beamline environment. A surface corrugation common to several bimorph mirrors and the removal of that corrugation by repolishing were both confirmed using this method. In the same way, mirrors curved in a controlled way with bending actuators and sag compensators could also be optimized. Fits to the elastic bending of ideal beams using the Euler-Bernoulli model have been performed on the slope errors of a mechanically bent mirror in order to distinguish bender curvatures from gravitational distortion and to calculate the compensating force that most reduces the latter effect. A successful improvement of the sag compensation mechanism of a vertically focusing mirror was also achieved, aided by a previously tested method for optimizing the settings of a mirror's actuators using pencil-beam scans.

Measurement and analysis of active synchrotron mirrors under operating conditions

International Nuclear Information System (INIS)

Sutter, John P.; Alcock, Simon G.; Sawhney, Kawal

2013-01-01

At the Diamond Light Source, in situ slope error measurements using the pencil-beam method have enabled X-ray mirror surfaces to be examined in their beamline environment. A surface corrugation common to several bimorph mirrors and the removal of that corrugation by repolishing were both confirmed using this method. In the same way, mirrors curved in a controlled way with bending actuators and sag compensators could also be optimized. Fits to the elastic bending of ideal beams using the Euler–Bernoulli model have been performed on the slope errors of a mechanically bent mirror in order to distinguish bender curvatures from gravitational distortion and to calculate the compensating force that most reduces the latter effect. A successful improvement of the sag compensation mechanism of a vertically focusing mirror was also achieved, aided by a previously tested method for optimizing the settings of a mirror's actuators using pencil-beam scans

Importance of non-parabolic band effects in the thermoelectric properties of semiconductors

Science.gov (United States)

Chen, Xin; Parker, David; Singh, David J.

2013-01-01

We present an analysis of the thermoelectric properties of of n-type GeTe and SnTe in relation to the lead chalcogenides PbTe and PbSe. We find that the singly degenerate conduction bands of semiconducting GeTe and SnTe are highly non-ellipsoidal, even very close to the band edges. This leads to isoenergy surfaces with a strongly corrugated shape that is clearly evident at carrier concentrations well below 0.005 e per formula unit (7–9 × 1019 cm−3 depending on material). Analysis within Boltzmann theory suggests that this corrugation may be favorable for the thermoelectric transport. Our calculations also indicate that values of the power factor for these two materials may well exceed those of PbTe and PbSe. As a result these materials may exhibit n-type performance exceeding that of the lead chalcogenides. PMID:24196778

Silicene on metal substrates: A first-principles study on the emergence of a hierarchy of honeycomb structures

International Nuclear Information System (INIS)

Kaltsas, D.; Tsetseris, L.; Dimoulas, A.

2014-01-01

Experimental studies have reported several types of Si monolayer structures that are formed on metal surfaces. These structures typically show the topology of a honeycomb bonding network, but differ in terms of corrugation and surface coverage. Using first-principles calculations, we identify atomic-scale mechanisms that underlie the appearance of different configurations as coverage increases during Si deposition on silver. The key point is that any extra Si adatoms that land on preformed silicene films can be incorporated in the honeycomb network and form bonds with underlying Ag atoms. As a result, the corrugation profile changes, giving rise to varying overlayer geometries. We also show that the same set of mechanisms control the appearance of silicene films on an iridium substrate. The results address available experimental data, but also probe the stability and properties of silicene wetting films that have not been observed yet.

Advanced Output Coupling for High Power Gyrotrons

Energy Technology Data Exchange (ETDEWEB)

Read, Michael [Calabazas Creek Research, Inc., San Mateo, CA (United States); Ives, Robert Lawrence [Calabazas Creek Research, Inc., San Mateo, CA (United States); Marsden, David [Calabazas Creek Research, Inc., San Mateo, CA (United States); Collins, George [Calabazas Creek Research, Inc., San Mateo, CA (United States); Temkin, Richard [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Guss, William [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Lohr, John [General Atomics, La Jolla, CA (United States); Neilson, Jeffrey [Lexam Research, Redwood City, CA (United States); Bui, Thuc [Calabazas Creek Research, Inc., San Mateo, CA (United States)

2016-11-28

The Phase II program developed an internal RF coupler that transforms the whispering gallery RF mode produced in gyrotron cavities to an HE11 waveguide mode propagating in corrugated waveguide. This power is extracted from the vacuum using a broadband, chemical vapor deposited (CVD) diamond, Brewster angle window capable of transmitting more than 1.5 MW CW of RF power over a broad range of frequencies. This coupling system eliminates the Mirror Optical Units now required to externally couple Gaussian output power into corrugated waveguide, significantly reducing system cost and increasing efficiency. The program simulated the performance using a broad range of advanced computer codes to optimize the design. Both a direct coupler and Brewster angle window were built and tested at low and high power. Test results confirmed the performance of both devices and demonstrated they are capable of achieving the required performance for scientific, defense, industrial, and medical applications.

He atom scattering from ZnO surfaces: calculation of diffraction peak intensities using the close-coupling approach

Energy Technology Data Exchange (ETDEWEB)

MartInez-Casado, R [Department of Chemistry, Imperial College London, South Kensington, London SW7 2AZ (United Kingdom); Miret-Artes, S [Instituto de Fisica Fundamental, Consejo Superior de Investigaciones CientIficas, Serrano 123, 28006 Madrid (Spain); Meyer, B [Interdisziplinaeres Zentrum fuer Molekulare Materialien ICMM and Computer-Chemie-Centrum CCC, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Naegelsbachstrasse 25, 91052 Erlangen (Germany); Traeger, F [Lehrstuhl fuer Physikalische Chemie I, Ruhr-Universitaet Bochum, 44801 Bochum (Germany); Woell, Ch, E-mail: r.martinezcasado@imperial.ac.u [Institut fuer Funktionelle Grenzflaechen, Karlsruher Institut fuer Technologie KIT, Kaiserstrasse 12, 76131 Karlsruhe (Germany)

2010-08-04

Diffraction intensities of a molecular He beam scattered off the clean and water-covered ZnO(101-bar0) surface have been simulated using a new potential model in conjunction with the close-coupling formalism. The effective corrugation functions for the systems He-ZnO(101-bar0) and He-H{sub 2}O/ZnO(101-bar0) have been obtained from density functional theory calculations within the Esbjerg-Noerskov approximation. Using these data a potential model is constructed consisting of a corrugated Morse potential at small He-surface distances and a semiempiric attractive part at larger distances. The diffraction patterns obtained from close-coupling calculations agree with the experimental data within about 10%, which opens the possibility to simulate He diffraction from surfaces of any structural complexity and to verify surface and adsorbate structures proposed theoretically by employing this kind of analysis.

Evaluation of muscle hyperactivity of the grimacing muscles by unilateral tight eyelid closure and stapedius muscle tone.

Science.gov (United States)

Shiba, Masato; Matsuo, Kiyoshi; Ban, Ryokuya; Nagai, Fumio

2012-10-01

Muscle hyperactivity of grimacing muscles, including the orbicularis oculi and corrugator supercilii muscles that cause crow's feet and a glabellar frown line with ageing, cannot be accurately evaluated by surface observation. In 71 subjects, this study investigated the extent to which grimacing muscles are innervated by the bilateral motor cortices, whether the corticofacial projection to the grimacing muscles affects the facially innervated stapedius muscle tone by measuring static compliance of the tympanic membrane, and whether unilateral tight eyelid closure with contraction of the grimacing muscles changes static compliance. Unilateral tight eyelid closure and its subsequent change in the contralateral vertical medial eyebrow position revealed that motor neurons of the orbicularis oculi and corrugator supercilii muscles were innervated by the bilateral motor cortices with weak-to-strong contralateral dominance. The orbicularis oculi, corrugator supercilii, and stapedius muscles innervated by the bilateral motor cortices had increased muscle hyperactivity, which lowered the vertical medial eyebrow position and decreased the static compliance of the tympanic membrane more than those innervated by the unilateral motor cortex. Unilateral enhanced tight eyelid closure with contraction of the grimacing muscles in certain subjects ipsilaterally decreased the static compliance with increased contraction of the stapedius muscle, which probably occurs to immobilise the tympanic membrane and protect the inner ear from loud sound. Evaluation of unilateral tight eyelid closure and the subsequent change in the contralateral vertical medial eyebrow position as well as a measurement of the static compliance for the stapedius muscle tone has revealed muscle hyperactivity of grimacing muscles.

Evaluation of low-frequency operational limit of proposed ITER low-field-side reflectometer waveguide run including miter bends

Energy Technology Data Exchange (ETDEWEB)

Wang, Guiding [Univ. of California, Los Angeles, CA (United States). Dept. of Physics and Astronomy and Plasma Science and Technology Inst. (PSTI); Peebles, W. A. [Univ. of California, Los Angeles, CA (United States). Dept. of Physics and Astronomy and Plasma Science and Technology Inst. (PSTI); Doyle, E. J. [Univ. of California, Los Angeles, CA (United States). Dept. of Physics and Astronomy and Plasma Science and Technology Inst. (PSTI); Crocker, N. A. [Univ. of California, Los Angeles, CA (United States). Dept. of Physics and Astronomy and Plasma Science and Technology Inst. (PSTI); Wannberg, C. [Univ. of California, Los Angeles, CA (United States). Dept. of Physics and Astronomy and Plasma Science and Technology Inst. (PSTI); Lau, Cornwall H. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hanson, Gregory R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Doane, John L. [General Atomics, San Diego, CA (United States)

2017-10-19

The present design concept for the ITER low-field-side reflectometer transmission line (TL) consists of an ~40 m long, 6.35 cm diameter helically corrugated waveguide (WG) together with ten 90° miter bends. This paper presents an evaluation of the TL performance at low frequencies (33-50 GHz) where the predicted HE11 mode ohmic and mode conversion losses start to increase significantly. Quasi-optical techniques were used to form a near Gaussian beam to efficiently couple radiation in this frequency range into the WG. We observed that the output beams from the guide remained linearly polarized with cross-polarization power levels of ~1.5%-3%. The polarization rotation due to the helical corrugations was in the range ~1°-3°. The radiated beam power profiles typically show excellent Gaussian propagation characteristics at distances >20 cm from the final exit aperture. The round trip propagation loss was found to be ~2.5 dB at 50 GHz and ~6.5 dB at 35 GHz, showing an inverse increase with frequency. This was consistent with updated calculations of miter bend and ohmic losses. At low frequencies (33-50 GHz), the mode purity remained very good at the exit of the waveguide, and the losses are perfectly acceptable for operation in ITER. Finally, the primary challenge may come from the future addition of a Gaussian telescope and other filter components within the corrugated guide, which will likely introduce additional perturbations to the beam profile and an increase in mode-conversion loss.

Towards understanding edge localised mode mitigation by resonant magnetic perturbations in MAST

Energy Technology Data Exchange (ETDEWEB)

Chapman, I. T.; Kirk, A.; Ham, C. J.; Harrison, J. R.; Liu, Y. Q.; Saarelma, S.; Scannell, R.; Thornton, A. J.; Team, MAST [EURATOM/CCFE Fusion Association, Culham Science Centre, Abingdon, Oxfordshire OX14 3DB (United Kingdom); Becoulet, M.; Orain, F. [Association Euratom/CEA, CEA Cadarache, IRFM, F-13108, St. Paul-lez-Durance (France); Cooper, W. A. [CRPP, Association EURATOM/Confédération Suisse, EPFL, 1015 Lausanne (Switzerland); Pamela, S. [IIFS-PIIM. Aix Marseille Université—CNRS, 13397 Marseille Cedex 20 (France)

2013-05-15

Type-I Edge Localised Modes (ELMs) have been mitigated in MAST through the application of n=3,4, and 6 resonant magnetic perturbations. For each toroidal mode number of the non-axisymmetric applied fields, the frequency of the ELMs has been increased significantly, and the peak heat flux on the divertor plates reduced commensurately. This increase in ELM frequency occurs despite a significant drop in the edge pressure gradient, which would be expected to stabilise the peeling-ballooning modes thought to be responsible for type-I ELMs. Various mechanisms which could cause a destabilisation of the peeling-ballooning modes are presented, including pedestal widening, plasma rotation braking, three dimensional corrugation of the plasma boundary, and the existence of radially extended lobe structures near to the X-point. This leads to a model aimed at resolving the apparent dichotomy of ELM control, which is to say ELM suppression occurring due to the pedestal pressure reduction below the peeling-ballooning stability boundary, whilst the reduction in pressure can also lead to ELM mitigation, which is ostensibly a destabilisation of peeling-ballooning modes. In the case of ELM mitigation, the pedestal broadening, 3d corrugation, or lobes near the X-point degrade ballooning stability so much that the pedestal recovers rapidly to cross the new stability boundary at lower pressure more frequently, whilst in the case of suppression, the plasma parameters are such that the particle transport reduces the edge pressure below the stability boundary, which is only mildly affected by negligible rotation braking, small edge corrugation or short, broad lobe structures.

Engagement and EMG in serious gaming : Experimenting with sound and dynamics in the levee patroller training game

NARCIS (Netherlands)

Schuurink, E.L.; Houtkamp, J.; Toet, A.

2008-01-01

We measured the effects of sound and visual dynamic elements on user experience of a serious game, with special interest in engagement and arousal. Engagement was measured through questionnaires and arousal through the SAM and electromyography (EMG). We adopted the EMG of the corrugator (frown

Structural Analysis of a Dragonfly Wing

NARCIS (Netherlands)

Jongerius, S.R.; Lentink, D.

2010-01-01

Dragonfly wings are highly corrugated, which increases the stiffness and strength of the wing significantly, and results in a lightweight structure with good aerodynamic performance. How insect wings carry aerodynamic and inertial loads, and how the resonant frequency of the flapping wings is tuned

A roadmap to high quality chemically prepared graphene

NARCIS (Netherlands)

Gengler, Regis Y. N.; Spyrou, Konstantinos; Rudolf, Petra

2010-01-01

Graphene was discovered half a decade ago and proved the existence of a two-dimensional system which becomes stable as a result of 3D corrugation. It appeared very quickly that this exceptional material had truly outstanding electronic, mechanical, thermal and optical properties. Consequently a

Disposal and Reuse of Eaker Air Force Base, Arkansas. Final Environmental Impact Statement

Science.gov (United States)

1992-11-01

stating what property is excess and surplus, and the terms and conditions under which the dispositions will be madr . These decisions may affect the...variety of materials including corrugated metal, brick, shingles, metal and wood siding, and stutco. Taller structures include one 3-story building

Cavitation Inception on Microparticles: A Self-Propelled Particle Accelerator

DEFF Research Database (Denmark)

Arora, M.; Ohl, C.-D.; Mørch, Knud Aage

2004-01-01

Corrugated, hydrophilic particles with diameters between 30 and 150 mum are found to cause cavitation inception at their surfaces when they are exposed to a short, intensive tensile stress wave. The growing cavity accelerates the particle into translatory motion until the tensile stress decreases...

77 FR 10560 - United States v. International Paper Company et al.; Proposed Final Judgment and Competitive...

Science.gov (United States)

2012-02-22

..., Antitrust Division, Antitrust Documents Group, 450 Fifth Street NW., Suite 1010, Washington, DC 20530... Packaging Group, which produces containerboard and corrugated products, accounting for $8.4 billion. 10... linerboards in a wavy, fluted pattern. Linerboard is made from virgin wood fiber, recycled fiber (usually...

How to build a small ferro-cement water tank: technical guide

CSIR Research Space (South Africa)

Sadzik, P

1988-05-01

Full Text Available This guide will assist on how to build a small water tank which can be used to store spring water, rainwater or water pumped from a stream or dam. Small water tanks can be constructed from many different materials such as corrugated iron, bricks...

Multidimensional Potential Energy Surface for H2 Dissociation over Cu(111)

DEFF Research Database (Denmark)

Hammer, Bjørk; Scheffler, Matthias; Jacobsen, Karsten Wedel

1994-01-01

We present ab initio density functional calculations within the generalized gradient approximation for H-2 dissociating over Cu(111). The minimum barrier for dissociation is 0.5 eV and shows large corrugation within the unit cell and a strong dependence on the molecular orientation. Dissociation...

Generalized Warburg impedance on realistic self-affine fractals ...

Indian Academy of Sciences (India)

2016-08-26

Aug 26, 2016 ... We analyse the problem of impedance for a diffusion controlled charge transfer process across an irregular interface. These interfacial irregularities are characterized as two class of random fractals: (i) a statistically isotropic self-affine fractals and (ii) a statistically corrugated self-affine fractals.

USSR Report, Translations from Kommunist, No. 12, August 1983.

Science.gov (United States)

1983-11-10

consequences of errors which have not been corrected on time, most firmly and unhesitatingly, not through meaningless statements and trivia but through real...manufacturing of containers made of paper and corrugated and flat glued cardboard and the recycling of wooden containers unsuitable for reuse. The USSR

Quasi-optical assessment of the ALMA band 9 front-end

NARCIS (Netherlands)

Candotti, Massimo; Baryshev, Andrey M.; Trappe, Neil

The ALMA band 9 (600-720 GHz) receiver is a dual channel heterodyne system which is capable of detecting orthogonally polarised signals utilising a wire grid beam splitter. Two Superconductor-Insulator-Superconductor (SIS) mixers mounted behind hybrid mode corrugated horns are coupled to the 12 m

Measurement of AC losses in different former materials

DEFF Research Database (Denmark)

Olsen, Søren Krüger; Træholt, Chresten; Kühle, Anders Van Der Aa

1998-01-01

candidates separately; for example copper tubes, stainless steel braid, copper braid, corrugated stainless steel tubes, etc. The measured data are compared with the predictions of a theoretical model. Our results show that in most cases, the losses induced by eddy currents in the former are negligible...

Survival tactics within thermally-challenging roosts: heat tolerance ...

African Journals Online (AJOL)

This roost was located in a 10 em deep cavity between a pitched (13°) corrugated .... of differences in the spatio-temporal profiles of roosts was tested using either ..... least two hours, indicating that they had entered a shallow tor-. pOL All of the ...

Embodied simulation as part of affective evaluation processes: task dependence of valence concordant EMG activity.

Science.gov (United States)

Weinreich, André; Funcke, Jakob Maria

2014-01-01

Drawing on recent findings, this study examines whether valence concordant electromyography (EMG) responses can be explained as an unconditional effect of mere stimulus processing or as somatosensory simulation driven by task-dependent processing strategies. While facial EMG over the Corrugator supercilii and the Zygomaticus major was measured, each participant performed two tasks with pictures of album covers. One task was an affective evaluation task and the other was to attribute the album covers to one of five decades. The Embodied Emotion Account predicts that valence concordant EMG is more likely to occur if the task necessitates a somatosensory simulation of the evaluative meaning of stimuli. Results support this prediction with regard to Corrugator supercilii in that valence concordant EMG activity was only present in the affective evaluation task but not in the non-evaluative task. Results for the Zygomaticus major were ambiguous. Our findings are in line with the view that EMG activity is an embodied part of the evaluation process and not a mere physical outcome.

Subnanometer Resolution and Enhanced Friction Contrast at the Surface of Perylene Diimide PDI8-CN2 Thin Films in Ambient Conditions.

Science.gov (United States)

Buzio, Renato; Gerbi, Andrea; Barra, Mario; Chiarella, Fabio; Gnecco, Enrico; Cassinese, Antonio

2018-03-13

We report high-resolution surface morphology and friction force maps of polycrystalline organic thin films derived by deposition of the n-type perylene diimide semiconductor PDI8-CN 2 . We show that the in-plane molecular arrangement into ordered, cofacial slip-stacked rows results in a largely anisotropic surface structure, with a characteristic sawtooth corrugation of a few Ångstroms wavelength and height. Load-controlled experiments reveal different types of friction contrast between the alternating sloped and stepped regions, with transitions from atomic-scale dissipative stick-slip to smooth sliding with ultralow friction within the surface unit cell. Notably, such a rich phenomenology is captured under ambient conditions. We demonstrate that friction contrast is well reproduced by numerical simulations assuming a reduced corrugation of the tip-molecule potential nearby the step edges. We propose that the side alkyl chains pack into a compact low-surface-energy overlayer, and friction modulation reflects periodic heterogeneity of chains bending properties and subsurface anchoring to the perylene cores.

Paper sludge (PS) to bioethanol: Evaluation of virgin and recycle mill sludge for low enzyme, high-solids fermentation.

Science.gov (United States)

Boshoff, Sonja; Gottumukkala, Lalitha Devi; van Rensburg, Eugéne; Görgens, Johann

2016-03-01

Paper sludge (PS) from the paper and pulp industry consists primarily of cellulose and ash and has significant potential for ethanol production. Thirty-seven PS samples from 11 South African paper and pulp mills exhibited large variation in chemical composition and resulting ethanol production. Simultaneous saccharification and fermentation (SSF) of PS in fed-batch culture was investigated at high solid loadings and low enzyme dosages. Water holding capacity and viscosity of the PS influenced ethanol production at elevated solid loadings of PS. High viscosity of PS from virgin pulp mills restricted the solid loading to 18% (w/w) at an enzyme dosage of 20 FPU/gram dry PS (gdPS), whereas an optimal solid loading of 27% (w/w) was achieved with corrugated recycle mill PS at 11 FPU/gdPS. Ethanol concentration and yield of virgin pulp and corrugated recycle PS were 34.2g/L at 66.9% and 45.5 g/L at 78.2%, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

Factors influencing the temporal growth rate of the high order TM{sub 0n} modes in the Ka-band overmoded Cherenkov oscillator

Energy Technology Data Exchange (ETDEWEB)

Wu, Dapeng, E-mail: vipbenjamin@163.com; Shu, Ting; Ju, Jinchuan [College of Photoelectric Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

2015-06-15

When the wavelength of overmoded Cherenkov oscillator goes into Ka-band, power handling capacity becomes an essential issue. Using the TM{sub 02} mode or higher order TM{sub 0n} modes as the operating mode is a potential solution. This paper is aimed to find some proper parameters to make the temporal growth rate of the TM{sub 02} mode higher in our previously studied Gigawatt (GW)-class Ka band oscillator. An accurate and fast calculation method of the “hot” dispersion equation is derived for rectangular corrugated SWSs, which are widely used in the high frequency Cherenkov devices. Then, factors that affect the temporal growth rate of the high order TM{sub 0n} modes are analyzed, including the depth of corrugation, the radius of drift tube, and the diode voltage. Results show that, when parameters are chosen properly, the temporal growth rate of the TM{sub 02} mode can be as high as 0.3 ns{sup −1}.

Solar energy operated still

Energy Technology Data Exchange (ETDEWEB)

Smith, F A

1977-03-31

A silicon membrane that is permeable to the vapour of a liquid to be distilled, is seeded with a light-absorbing pigment, and used in conjunction with a light-transparent material in one of three configurations as a solar powered still. In the first configuration, the membrane is in the form of a corrugated surface welded to the transparent material along the corrugations, forming a series of channel-like air chambers. This assembly floats on the liquid, the transparent side being on top and exposed to the sun. Vapour condensing in the channels is collected. In the second configuration, the liquid is contained between a sheet of transparent material on top, and a sheet of membrane material underneath. Vapour condenses in a chamber beneath. In the third configuration, membrane material is in the form of a pipe containing the liquid. A second concentral pipe of transparent material surrounds it and ensures collection of the condensate.

Saturation mechanism of decaying ion temperature gradient driven turbulence with kinetic electrons

International Nuclear Information System (INIS)

Idomura, Yasuhiro

2016-01-01

We present full-f gyrokinetic simulations of the ion temperature gradient driven (ITG) turbulence including kinetic electrons. By comparing decaying ITG turbulence simulations with adiabatic and kinetic electron models, an impact of kinetic electrons on the ITG turbulence is investigated. It is found that significant electron transport occurs even in the ITG turbulence, and both ion and electron temperature profiles are relaxed. In steady states, both cases show upshifts of nonlinear critical ion temperature gradients from linear ones, while their saturation mechanisms are qualitatively different. In the adiabatic electron case, the ITG mode is stabilized by turbulence driven zonal flows. On the other hand, in the kinetic electron case, passing electrons transport shows fine resonant structures at mode rational surfaces, which generate corrugated density profiles. Such corrugated density profiles lead to fine radial electric fields following the neoclassical force balance relation. The resulting E × B shearing rate greatly exceeds the linear growth rate of the ITG mode. (author)

Facial electromyogram and heart-rate correlates of a paradoxical attitude change to antinuclear war information

International Nuclear Information System (INIS)

Vigne, J.J.; Dale, J.A.; Klions, H.L.

1988-01-01

The effects of film images versus film descriptions of the effects of nuclear explosions (versus a no-film control) on corrugator muscle tension, heart rate, attitude and mood were investigated. The last 5 min. of the images were associated with more corrugator tension for that condition when compared to the last 5 min. of the description condition. The groups did not differ in heart rate but women in both groups showed an increase in heart rate whereas men in both groups showed a decrease in heart rate. Film groups did not differ in their significant increases in anxiety, hostility, and depression on the Multiple Adjective Affect Checklist. On the pretest there was no significant correlation between scores on Betts' Questionnaire Upon Mental Imagery and scores on Goldenring and Doctor's index of concern for nuclear war. The vivid-image film group showed a decrease in concern for nuclear war when compared to the descriptive film group and the no-film control

The wrinkled patellar tendon: An indication of abnormality in the extensor mechanism of the knee

International Nuclear Information System (INIS)

Berlin, R.C.; Levinsohn, E.M.; Chrisman, H.

1991-01-01

Rupture of the quadriceps tendon is an uncommon condition which requires early diagnosis and treatment to avert prolonged disability. In four patients who had surgically confirmed quadriceps tendon rupture, lateral radiographs of the knee and/or sagittal magnetic resonance (MR) images demonstrated a corrugated appearance to the patellar tendon. Sagittal MR images of the knee following patellectomy in one patient and radiographs of a transverse fracture of the patella in another also demonstrated this appearance. MRI has superb contrast resolution which provides optimal visualization of the contour of the patellar tendon on sagittal images. A retrospective review of 50 consecutive knee MRI examinations was carried out to evaluate the appearance of the normal patellar tendon. In 49 of 50 patients, the sagittal images demonstrated a straight or nearly straight patellar tendon. A corrugated appearance of the patellar tendon on sagittal images indicates a reduction in the normal tensile force applied to it and indicates the need for careful evaluation of the patella and quadriceps tendon mechanism. (orig.)

Bending sound in graphene: Origin and manifestation

Energy Technology Data Exchange (ETDEWEB)

Adamyan, V.M., E-mail: vadamyan@onu.edu.ua [Department of Theoretical Physics, Odessa I.I. Mechnikov National University, 2 Dvoryanska St., Odessa 65026 (Ukraine); Bondarev, V.N., E-mail: bondvic@onu.edu.ua [Department of Theoretical Physics, Odessa I.I. Mechnikov National University, 2 Dvoryanska St., Odessa 65026 (Ukraine); Zavalniuk, V.V., E-mail: vzavalnyuk@onu.edu.ua [Department of Theoretical Physics, Odessa I.I. Mechnikov National University, 2 Dvoryanska St., Odessa 65026 (Ukraine); Department of Fundamental Sciences, Odessa Military Academy, 10 Fontanska Road, Odessa 65009 (Ukraine)

2016-11-11

Highlights: • The origin of sound-like dispersion of graphene bending mode is disclosed. • The speed of graphene bending sound is determined. • The renormalized graphene bending rigidity is derived. • The intrinsic corrugations of graphene are estimated. - Abstract: It is proved that the acoustic-type dispersion of bending mode in graphene is generated by the fluctuation interaction between in-plane and out-of-plane terms in the free energy arising with account of non-linear components in the graphene strain tensor. In doing so we use an original adiabatic approximation based on the alleged (confirmed a posteriori) significant difference of sound speeds for in-plane and bending modes. The explicit expression for the bending sound speed depending only on the graphene mass density, in-plane elastic constants and temperature is deduced as well as the characteristics of the microscopic corrugations of graphene. The obtained results are in good quantitative agreement with the data of real experiments and computer simulations.

Bending sound in graphene: Origin and manifestation

International Nuclear Information System (INIS)

Adamyan, V.M.; Bondarev, V.N.; Zavalniuk, V.V.

2016-01-01

Highlights: • The origin of sound-like dispersion of graphene bending mode is disclosed. • The speed of graphene bending sound is determined. • The renormalized graphene bending rigidity is derived. • The intrinsic corrugations of graphene are estimated. - Abstract: It is proved that the acoustic-type dispersion of bending mode in graphene is generated by the fluctuation interaction between in-plane and out-of-plane terms in the free energy arising with account of non-linear components in the graphene strain tensor. In doing so we use an original adiabatic approximation based on the alleged (confirmed a posteriori) significant difference of sound speeds for in-plane and bending modes. The explicit expression for the bending sound speed depending only on the graphene mass density, in-plane elastic constants and temperature is deduced as well as the characteristics of the microscopic corrugations of graphene. The obtained results are in good quantitative agreement with the data of real experiments and computer simulations.

Theoretical investigation of the Fermi surfaces of La2-xSrxCuO4 and YBa2Cu3O7

International Nuclear Information System (INIS)

Antonov, V.N.; Antonov, Vl.N.; Bar'yakhtar, V.G.; Baglyuk, A.I.; Maksimov, E.G.; Nemoshkalenko, V.V.; Perlov, A.Ya.; Savrasov, S.Yu.; Uspenskii, Yu.A.

1989-01-01

A theoretical investigation is made of the shape of the Fermi surface and of the constant-energy surfaces near the Fermi energy of the La 2-x Sr x CuO 4 and YBa 2 Cu 3 O 7 oxides by a self-consistent linear muffin-tin orbital method in the atomic sphere approximation (OMTO-ASA). It is shown that the Fermi surfaces of these compounds are strongly two-dimensional. The Fermi surface of La 2-x Sr x CuO 4 is a corrugated rounded box centered at the point Λ. The Fermi surface of YBa 2 Cu 3 O 7 consists of four sheets: an electron cushion at the point Λ and three nested hole surfaces centered at the point S. The electron cushion and one of the hole surfaces are strongly corrugated along the z direction. The theoretically calculated Fermi surfaces of La 2 CuO 4 and YBa 2 Cu 3 O 7 are compared with the experimental data on electron-positron annihilation

Cavitation inception on microparticles: a self-propelled particle accelerator

NARCIS (Netherlands)

Arora, M.; Ohl, C.D.; Morch, Knud Aage

2004-01-01

Corrugated, hydrophilic particles with diameters between 30 and 150   μm are found to cause cavitation inception at their surfaces when they are exposed to a short, intensive tensile stress wave. The growing cavity accelerates the particle into translatory motion until the tensile stress decreases,

Qualification of new design of flexible pipe against singing: testing at multiple scales

NARCIS (Netherlands)

Golliard, J.; Lunde, K.; Vijlbrief, O.

2016-01-01

Flexible pipes for production of oil and gas typically present a corrugated inner surface. This has been identified as the cause of "singing risers": Flow-Induced Pulsations due to the interaction of sound waves with the shear layers at the small cavities present at each of the multiple

Generalized Warburg impedance on realistic self-affine fractals

Indian Academy of Sciences (India)

We analyse the problem of impedance for a diffusion controlled charge transfer process across an irregular interface. These interfacial irregularities are characterized as two class of random fractals: (i) a statistically isotropic self-affine fractals and (ii) a statistically corrugated self-affine fractals. The information about the ...

Light scattering by soap films

NARCIS (Netherlands)

Vrij, A.

A theory is constructed describing the scattering from a liquid film (e.g., a soap film) of a light beam polarized normal to the plane of incidence. This scattering is due to the small irregular corrugations caused by thermal motion. The interference of the reflected incident beam with its multiple

Cavitation inception on micro-particles: a self propelled particle accelerator

NARCIS (Netherlands)

Arora, M.; Ohl, C.D.; Morch, Knud Aage; Gutkowski, Witold; Kowalewski, Tomasz A.

2004-01-01

Corrugated, hydrophilic particles with diameters between 30 �m and 150 �m are found to cause cavitation inception at their surfaces when they are exposed to a short, intensive tensile stress wave. The growth of cavity and its interaction with the original nucleating particle is recorded by means of

Financial Management of Hazardous Waste Compliance and Mitigation Costs: Constraints and Implications

Science.gov (United States)

1991-12-01

materials. TABLE I DRMO Market Price Paper $ 45 / ton Canvas $ 0.024 / lb Aluminum $ 0.26/1b Tires * $ 0.02 / lb Corrugated $ 63 /ton Silver Reclaimed...quality control check in accordance with their permit requirements. They pull samples and do a fingerprint analysis. If during that analysis they find that

Power-law load dependence of atomic friction

NARCIS (Netherlands)

Fusco, C.; Fasolino, A.

2004-01-01

We present a theoretical study of the dynamics of a tip scanning a graphite surface as a function of the applied load. From the analysis of the lateral forces, we extract the friction force and the corrugation of the effective tip-surface interaction potential. We find both the friction force and

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

The absolute temperature of the cosmic microwave back-ground (CMB) has been measured at a frequency of 1280 MHz. The observation was made with a modified version of the L-band receiver used in the Giant Metre wavelength Radio Telescope (GMRT): the feed horn was replaced by a corrugated plate and the ...

Evaluation of five sampling methods for Liposcelis entomophila (Enderlein) and L. decolor (Pearman) (Psocoptera: Liposcelididae) in steel bins containing wheat

Science.gov (United States)

An evaluation of five sampling methods for studying psocid population levels was conducted in two steel bins containing 32.6 metric tonnes of wheat in Manhattan, KS. Psocids were sampled using a 1.2-m open-ended trier, corrugated cardboard refuges placed on the underside of the bin hatch or the surf...

The effect of surface roughness on the adhesion of solid surfaces for systems with and without liquid lubricant

DEFF Research Database (Denmark)

Samoilov, V. N.; Sivebæk, Ion Marius; Persson, B. N. J.

2004-01-01

We present molecular dynamics results for the interaction between two solid elastic walls during pull-off for systems with and without octane (C8H18) lubricant. We used two types of substrate-flat and corrugated-and varied the lubricant coverage from similar to1/8 to similar to4 ML (monolayers...

Proceedings, sixth international symposium : moisture and creep effects on paper, board and containers: Madison, Wisconsin, USA, 14-15 July 2009

Science.gov (United States)

John M. Considine; Sally A. Ralph

2011-01-01

The USDA Forest Products Laboratory sponsored the 6th International Symposium: Moisture and Creep Effects on Paper, Board and Containers at the Monona Terrace Convention Center, Madison, WI, USA on 14-15 July 2009. Attendees heard 20 technical presentations; presenters were from seven different countries and three continents. Session topics included Corrugated...

Analisa Performansi Destilasi Air Laut Tenaga Surya Menggunakan Penyerap Radiasi Surya Tipe Bergelombang Berbahan Dasar Beton

Directory of Open Access Journals (Sweden)

Ketut Astawa

2012-11-01

Full Text Available In principle, the distillation is a way to get clean water through desalination process dirty. In the refining processthere is a process of heat transfer, evaporation, and condensation. Heat transfer occurs from the heat source to the dirtywater. If water continues - it will happen again heated evaporation process. This steam on contact with cold surfaces it willbe a process of condensation on cold surfaces. In the distillation process condensate water is captured, germs and bacteriawill die by the heating process, and dirt will settle to the bottom basin One can use the sun's energy.In the system of solar distillation of sea water, absorber plate very important role because it serves as an absorberof solar radiation and convert light into heat energy that will heat the sea water above it. Based on the initial hypothesis ofthe authors that the type of flat-plate absorber is less than optimal, I will attempt to create a design and compare theperformance of sea water distillation appliance that uses a flat type absorber, absorber types of wavy, and wavy-coatedabsorbent type gravel. On the premise that type absorber has a broad corrugated heat absorption field is greater than theflat type absorber.Tests conducted from 09:00 am until 17:00 pm. The volume of sea water in the test as much as 30 liters. Testresults show the type of radiation absorber coated corrugated gravel produces more condensate is equal to 1295 grams withan average efficiency reaches 12.33%, and the type of radiation absorbent corrugated produce condensate for 1250 gramswith an average efficiency reaches 12.84% . While the radiation absorber can only produce a flat type of 795 ml with anaverage efficiency reaches 8.48%.

Less Empathic and More Reactive: The Different Impact of Childhood Maltreatment on Facial Mimicry and Vagal Regulation.

Directory of Open Access Journals (Sweden)

Martina Ardizzi

Full Text Available Facial mimicry and vagal regulation represent two crucial physiological responses to others' facial expressions of emotions. Facial mimicry, defined as the automatic, rapid and congruent electromyographic activation to others' facial expressions, is implicated in empathy, emotional reciprocity and emotions recognition. Vagal regulation, quantified by the computation of Respiratory Sinus Arrhythmia (RSA, exemplifies the autonomic adaptation to contingent social cues. Although it has been demonstrated that childhood maltreatment induces alterations in the processing of the facial expression of emotions, both at an explicit and implicit level, the effects of maltreatment on children's facial mimicry and vagal regulation in response to facial expressions of emotions remain unknown. The purpose of the present study was to fill this gap, involving 24 street-children (maltreated group and 20 age-matched controls (control group. We recorded their spontaneous facial electromyographic activations of corrugator and zygomaticus muscles and RSA responses during the visualization of the facial expressions of anger, fear, joy and sadness. Results demonstrated a different impact of childhood maltreatment on facial mimicry and vagal regulation. Maltreated children did not show the typical positive-negative modulation of corrugator mimicry. Furthermore, when only negative facial expressions were considered, maltreated children demonstrated lower corrugator mimicry than controls. With respect to vagal regulation, whereas maltreated children manifested the expected and functional inverse correlation between RSA value at rest and RSA response to angry facial expressions, controls did not. These results describe an early and divergent functional adaptation to hostile environment of the two investigated physiological mechanisms. On the one side, maltreatment leads to the suppression of the spontaneous facial mimicry normally concurring to empathic understanding of

Appraisals Generate Specific Configurations of Facial Muscle Movements in a Gambling Task: Evidence for the Component Process Model of Emotion.

Science.gov (United States)

Gentsch, Kornelia; Grandjean, Didier; Scherer, Klaus R

2015-01-01

Scherer's Component Process Model provides a theoretical framework for research on the production mechanism of emotion and facial emotional expression. The model predicts that appraisal results drive facial expressions, which unfold sequentially and cumulatively over time. In two experiments, we examined facial muscle activity changes (via facial electromyography recordings over the corrugator, cheek, and frontalis regions) in response to events in a gambling task. These events were experimentally manipulated feedback stimuli which presented simultaneous information directly affecting goal conduciveness (gambling outcome: win, loss, or break-even) and power appraisals (Experiment 1 and 2), as well as control appraisal (Experiment 2). We repeatedly found main effects of goal conduciveness (starting ~600 ms), and power appraisals (starting ~800 ms after feedback onset). Control appraisal main effects were inconclusive. Interaction effects of goal conduciveness and power appraisals were obtained in both experiments (Experiment 1: over the corrugator and cheek regions; Experiment 2: over the frontalis region) suggesting amplified goal conduciveness effects when power was high in contrast to invariant goal conduciveness effects when power was low. Also an interaction of goal conduciveness and control appraisals was found over the cheek region, showing differential goal conduciveness effects when control was high and invariant effects when control was low. These interaction effects suggest that the appraisal of having sufficient control or power affects facial responses towards gambling outcomes. The result pattern suggests that corrugator and frontalis regions are primarily related to cognitive operations that process motivational pertinence, whereas the cheek region would be more influenced by coping implications. Our results provide first evidence demonstrating that cognitive-evaluative mechanisms related to goal conduciveness, control, and power appraisals affect

Theoretical study of noble gases diffraction from Ru(0001) using van der Waals DFT-based potentials

International Nuclear Information System (INIS)

Del Cueto, M; Muzas, A S; Martín, F; Díaz, C

2015-01-01

This study aims to analyze the role of van der Waals forces in the diffraction process of noble gases from a metal surface. We made use of different vdW implementations to rationalize the effect of dispersion forces on the corrugation of the system, the resulting scattering patterns and on the eventual diffraction results. (paper)

Supplementary Material

Indian Academy of Sciences (India)

mraga

1. Supplementary Material. A soluble-lead Redox Flow Battery with corrugated graphite sheet and reticulated vitreous carbon as positive and negative current collectors by A Banerjee et al (pp 163-. 170). Figure S1. SEM images for bare substrates: (a) graphite sheet, (b) 20 ppi RVC, (c) 30 ppi. RVC and (d) 45 ppi RVC.

Highly Conformal Ni Micromesh as a Current Collecting Front Electrode for Reduced Cost Si Solar Cell

DEFF Research Database (Denmark)

Gupta, Nikita; Rao, K. D. M.; Gupta, Ritu

2017-01-01

deposition of Ni wire network on corrugated solar cell, a short circuit current of 33.28 mA/cm2 was obtained in comparison to 20.53 mA/cm2 without the network electrode. On comparing the efficiency with the conventional cells with screen printed electrodes, a 20% increment in efficiency has been observed...

Molecular-beam epitaxy on shallow mesa gratings patterned on GaAs(311)A and (100) substrates

NARCIS (Netherlands)

Gong, Q.; Nötzel, R.; Schönherr, H.-P.; Ploog, K.H.

2002-01-01

We report on the morphology and properties of the surface formed by molecular-beam epitaxy on shallow mesa gratings on patterned GaAs(311)A and GaAs(100). On GaAs(311)A substrates, the corrugated surface formed after GaAs growth on shallow mesa gratings along [011] is composed of monolayer high

Generalized Warburg impedance on realistic self-affine fractals ...

Indian Academy of Sciences (India)

Administrator

Generalized Warburg impedance on realistic self-affine fractals: Comparative study of statistically corrugated and isotropic roughness. RAJESH KUMAR and RAMA KANT. Journal of Chemical Sciences, Vol. 121, No. 5, September 2009, pp. 579–588. 1. ( ) c. L. R ω on page 582, column 2, para 2, after eq (8) should read as ...

Combined nanoimprint and photolithography of integrated polymer optics

DEFF Research Database (Denmark)

Christiansen, Mads Brøkner; Schøler, Mikkel; Gersborg-Hansen, Morten

2007-01-01

are defined in SU-8 resist, doped with Rhodamine 6G laser dye, shaped as planar slab waveguides on a Fused Silica buffer substrate, and with a lst-order DFB surface corrugation forming the laser resonator. When optically pumped at 532 nm, lasing is obtained in the wavelength range 560 nm -600 nm, determined...

Benchmark Testing of the Largest Titanium Aluminide Sheet Subelement Conducted

Science.gov (United States)

Bartolotta, Paul A.; Krause, David L.

2000-01-01

To evaluate wrought titanium aluminide (gamma TiAl) as a viable candidate material for the High-Speed Civil Transport (HSCT) exhaust nozzle, an international team led by the NASA Glenn Research Center at Lewis Field successfully fabricated and tested the largest gamma TiAl sheet structure ever manufactured. The gamma TiAl sheet structure, a 56-percent subscale divergent flap subelement, was fabricated for benchmark testing in three-point bending. Overall, the subelement was 84-cm (33-in.) long by 13-cm (5-in.) wide by 8-cm (3-in.) deep. Incorporated into the subelement were features that might be used in the fabrication of a full-scale divergent flap. These features include the use of: (1) gamma TiAl shear clips to join together sections of corrugations, (2) multiple gamma TiAl face sheets, (3) double hot-formed gamma TiAl corrugations, and (4) brazed joints. The structural integrity of the gamma TiAl sheet subelement was evaluated by conducting a room-temperature three-point static bend test.

Computer program for calculating the resonant frequency, shunt impedance and quality factor of a pill-box cavity in a storage ring

International Nuclear Information System (INIS)

Aguero, V.M.; Ng, K.Y.

1983-10-01

Keil and Zotter have analyzed the electromagnetic fields excited by the longitudinal density fluctuations of an unbunched relativistic particle beam drifting in a corrugated vacuum chamber of circular cross section. At higher frequencies, these corrugations become resonant cavities. Zotter has written a computer program known as KN7C to compute the resonant frequencies. However, in the actual use of KN7C, some difficulties are encountered. To surmount these difficulties, the program known as CAVITY was written to analyze this pill-box shaped resonant cavity. Although there are many input variables to this program, only two are essential and need to be specified. They are BD = b/d = the ratio of the circular beampipe radius to that of the pill-box cavity and GD = g/d where g is the length of the cavity. When they are specified, CAVITY will print out the dimensionless normalized fundamental resonant frequency FD, shunt impedance Z and figure of merit Q. From these, the actual resonant frequency, shunt impedance and figure of merit can be deduced. The program is described and a listing is provided

Using the graphene Moiré pattern for the trapping of C60 and homoepitaxy of graphene.

Science.gov (United States)

Lu, Jiong; Yeo, Pei Shan Emmeline; Zheng, Yi; Yang, Zhiyong; Bao, Qiaoliang; Gan, Chee Kwan; Loh, Kian Ping

2012-01-24

The graphene Moiré superstructure offers a complex landscape of humps and valleys to molecules adsorbing and diffusing on it. Using C(60) molecules as the classic hard sphere analogue, we examine its assembly and layered growth on this corrugated landscape. At the monolayer level, the cohesive interactions of C(60) molecules adsorbing on the Moiré lattice freeze the molecular rotation of C(60) trapped in the valley sites, resulting in molecular alignment of all similarly trapped C(60) molecules at room temperature. The hierarchy of adsorption potential well on the Moiré lattice causes diffusion-limited dendritic growth of C(60) films, as opposed to isotropic growth observed on a smooth surface like graphite. Due to the strong binding energy of the C(60) film, part of the dentritic C(60) films polymerize at 850 K and act as solid carbon sources for graphene homoepitaxy. Our findings point to the possibility of using periodically corrugated graphene in molecular spintronics due to its ability to trap and align organic molecules at room temperature. © 2011 American Chemical Society

Morphological effect of a scallop shell on a flapping-type tidal stream generator

International Nuclear Information System (INIS)

Le, Tuyen Quang; Ko, Jin Hwan; Byun, Doyoung

2013-01-01

Inspired by nature, flapping-type tidal stream generators have been introduced in recent years. The improvement in their power generation ability is known to be a critical factor in the success of these generators. So far, corrugation and camber observed in flying insects and swimming animals are known to enhance the performance of a flapping-type propulsive system. In this study, we explore the effect of corrugation and camber in a system that mimics a scallop shell in terms of its ability to extract flow energy through a two-dimensional Navier–Stokes simulation. The simulations show that the size and the activity of the leading edge vortex are strongly affected by the morphological factors of the mimicked foils, the effects of which are then advantageous in terms of the power efficiency of the flapping-type tidal stream generator. Eventually, an optimal mimicked foil, as suggested based on the morphological effects, would be a good alternative type of foil with a typical section with regard to the hydrodynamic performance and structural properties of tidal stream generators. (paper)

Compound La[B5O8(OH)2] with a new type of pentaborate layer based on the 5[3T + 2Δ] block: Topology-symmetry analysis and the position in the structural system

International Nuclear Information System (INIS)

Ivanova, A. G.; Belokoneva, E. L.; Dimitrova, O. V.; Mochenova, N. N.

2006-01-01

Crystals of a new rare-earth borate, LaB 5 O 8 (OH) 2 (space group P2 1 /n), are synthesized under hydrothermal conditions. The crystal structure is determined by the heavy-atom method without prior knowledge of the chemical formula. The radical anion is a layer composed of pentaborate blocks 5[3T + 2Δ]. The topological and symmetric patterns of their condensation differ from those observed in all known layered pentaborates containing the same block. The building blocks are shared by vertices of tetrahedra to form chains. These chains are joined into a corrugated layer in such a way that one of the BO 3 triangles of the building block is terminal and the layer itself is denser than those previously revealed in all other borates. In contrast to the majority of layer borates, the new La borate does not contain water molecules, because it crystallizes from more concentrated solutions. The La atoms are located inside the walls of the hollows of corrugated layers, thus centering the holes of the layers

Experimental Study of Single Phase Flow in a Closed-Loop Cooling System with Integrated Mini-Channel Heat Sink

Directory of Open Access Journals (Sweden)

Lei Ma

2016-06-01

Full Text Available The flow and heat transfer characteristics of a closed-loop cooling system with a mini-channel heat sink for thermal management of electronics is studied experimentally. The heat sink is designed with corrugated fins to improve its heat dissipation capability. The experiments are performed using variable coolant volumetric flow rates and input heating powers. The experimental results show a high and reliable thermal performance using the heat sink with corrugated fins. The heat transfer capability is improved up to 30 W/cm2 when the base temperature is kept at a stable and acceptable level. Besides the heat transfer capability enhancement, the capability of the system to transfer heat for a long distance is also studied and a fast thermal response time to reach steady state is observed once the input heating power or the volume flow rate are varied. Under different input heat source powers and volumetric flow rates, our results suggest potential applications of the designed mini-channel heat sink in cooling microelectronics.

Mode splitting effect in FEMs with oversized Bragg resonators

Energy Technology Data Exchange (ETDEWEB)

Peskov, N. Yu.; Sergeev, A. S. [Institute of Applied Physics Russian Academy of Sciences, Nizhny Novgorod (Russian Federation); Kaminsky, A. K.; Perelstein, E. A.; Sedykh, S. N. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Kuzikov, S. V. [Institute of Applied Physics Russian Academy of Sciences, Nizhny Novgorod (Russian Federation); Nizhegorodsky State University, Nizhny Novgorod (Russian Federation)

2016-07-15

Splitting of the fundamental mode in an oversized Bragg resonator with a step of the corrugation phase, which operates over the feedback loop involving the waveguide waves of different transverse structures, was found to be the result of mutual influence of the neighboring zones of the Bragg scattering. Theoretical description of this effect was developed within the framework of the advanced (four-wave) coupled-wave approach. It is shown that mode splitting reduces the selective properties, restricts the output power, and decreases the stability of the narrow-band operating regime in the free-electron maser (FEM) oscillators based on such resonators. The results of the theoretical analysis were confirmed by 3D simulations and “cold” microwave tests. Experimental data on Bragg resonators with different parameters in a 30-GHz FEM are presented. The possibility of reducing the mode splitting by profiling the corrugation parameters is shown. The use of the mode splitting effect for the output power enhancement by passive compression of the double-frequency pulse generated in the FEM with such a resonator is discussed.

Emotional Reactivity and Appraisal of Food in Relation to Eating Disorder Cognitions and Behaviours: Evidence to Support the Motivational Conflict Hypothesis.

Science.gov (United States)

Racine, Sarah E; Hebert, Karen R; Benning, Stephen D

2018-01-01

Eating disorders are associated with both negative and positive emotional reactions towards food. Individual eating disorder symptoms may relate to distinct emotional responses to food, which could necessitate tailored treatments based on symptom presentation. We examined associations between eating disorder symptoms and psychophysiological responses to food versus neutral images in 87 college students [mean (SD) age = 19.70 (2.09); mean (SD) body mass index = 23.25(2.77)]. Reflexive and facial electromyography measures tapping negative emotional reactivity (startle blink reflex) and appraisal (corrugator muscle response) as well as positive emotional reactivity (postauricular reflex) and appraisal (zygomaticus muscle response) were collected. Eating disorder cognitions correlated with more corrugator activity to food versus neutral images, indicating negative appraisals of food. Binge eating was associated with increased postauricular reflex reactivity to food versus neutral images, suggesting enhanced appetitive motivation to food. The combination of cognitive eating disorder symptoms and binge eating may result in motivational conflict towards food. Copyright © 2017 John Wiley & Sons, Ltd and Eating Disorders Association. Copyright © 2017 John Wiley & Sons, Ltd and Eating Disorders Association.

Manipulating affective state using extended picture presentations.

Science.gov (United States)

Sutton, S K; Davidson, R J; Donzella, B; Irwin, W; Dottl, D A

1997-03-01

Separate, extended series of positive, negative, and neutral pictures were presented to 24 (12 men, 12 women) undergraduates. Each series was presented on a different day, with full counterbalancing of presentation orders. Affective state was measured using (a) orbicularis oculi activity in response to acoustic startle probes during picture presentation, (b) corrugator supercilii activity between and during picture presentation, and (c) changes in self-reports of positive and negative affect. Participants exhibited larger eyeblink reflex magnitudes when viewing negative than when viewing positive pictures. Corrugator activity was also greater during the negative than during the positive picture set, during both picture presentation and the period between pictures. Self-reports of negative affect increased in response to the negative picture set, and self-reports of positive affect were greatest following the positive picture set. These findings suggest that extended picture presentation is an effective method of manipulating affective state and further highlight the utility of startle probe and facial electromyographic measures in providing on-line readouts of affective state.

Diffractive scattering of H atoms from the (001) surface of LiF at 78 K

International Nuclear Information System (INIS)

Caracciolo, G.; Iannotta, S.; Scoles, G.; Valbusa, U.

1980-01-01

We have built an apparatus for the measurement of high resolution diffractive scattering of hydrogen atoms from crystal surfaces. The apparatus comprises a hydrogen atom beam source, a hexapolar magnetic field velocity selector, a variable temperature UHV crystal manipulator, and a rotatable bolometer detector. The diffraction pattern of a beam of hydrogen atoms scattered by a (001) LiF surface at 78 K has been obtained for different angles of incidence and different orientations of the crystal. The Debye--Waller factor has been measured leading to a surface Debye temperature theta/sub S/=550 +- 38 K. The corrugated-hard-wall-with-a-well model of Garibaldi et al. [Surf. Sci. 48, 649 (1975)] has been used for the interpretation of the intensities of the diffracted peaks. By means of a best fit procedure we obtain a main ''corrugation'' parameter xi 0 =0.095 A. By comparison of the data with the theory of Cabrera et al. [Surf. Sci. 19, 70 (1967] at the first order, the strength parameters of a periodic Morse potential have been determined

Evaluation of the imaging properties of Microwave Imaging Reflectometry

International Nuclear Information System (INIS)

Hong, I; Lee, W; Leem, J; Nam, Y; Kim, M; Yun, G S; Park, H K; Domier, C W; Jr, N C Luhmann

2012-01-01

Microwave Imaging Reflectometry (MIR) has been developed for unambiguous measurement of electron density fluctuations in fusion plasmas. The loss of phase information limiting the use of conventional reflectometry can be minimized by a large aperture imaging optics and an array of detectors in the MIR embodiment. The evaluation of the optical system is critical for precise reconstruction of the fluctuations. The optical systems of the prototype TEXTOR MIR [2] and newly-designed KSTAR MIR [5] systems have been tested with a corrugated target simulating density fluctuations at the cut-off surface. The reconstructed phase from the MIR system has been compared to the directly measured phase of corrugations taking into account the rotational speed of the target. The effects of optical aberrations and interference between lenses on the phase reconstruction have been investigated by the 2D amplitude measurement of the reflected waves and the diffraction-based optical simulations. (CODE V) A preliminary design of the KSTAR MIR optics has been suggested which can minimize the aberration and interference effects.

Effect for hydrogen, nitrogen, phosphorous, and argon ions irradiation on ZnO NWs

International Nuclear Information System (INIS)

Ishaq, A.; Usman, M.; Dee, C. F.; Khurram, A. A.; Yan, L.; Zhou, X. T.; Nadeem, A.; Naseem, S.; Rafique, H. M.; Majlis, B. Y.

2013-01-01

Zinc oxide (ZnO) nanowires (NWs) are exposed to energetic proton (H + ), nitrogen (N + ), phosphorus (P + ), and argon (Ar + ) ions to understand the radiation hardness and structural changes induced by these irradiations. High-resolution transmission electron microscopy is utilized to see the irradiation effects in NWs. Multiple doses and energies of radiation at different temperatures are used for different set of samples. The study reveals that wurtzite (crystalline)-structured ZnO NWs experience amorphization, degradation, and morphological changes after the irradiation. At room temperature, deterioration of the crystalline structure is observed under high fluence of H + , N + , and P + ions. While for ZnO NWs, bombarded by Ar + and P + ions, nano-holes are produced. The ZnO NWs surfaces also show corrugated morphology full of nano-humps when irradiated by Ar + ions at 400 °C. The corrugated surface could serve as tight-holding interface when interconnecting it with other NWs/nanotubes. These nano-humps may have the function of increasing the surface for surface-oriented sensing applications in the future.

Effect for hydrogen, nitrogen, phosphorous, and argon ions irradiation on ZnO NWs

Energy Technology Data Exchange (ETDEWEB)

Ishaq, A., E-mail: ishaq_ah@yahoo.com; Usman, M. [National Centre for Physics, Quaid-i-Azam University, Experimental Physics Labs (Pakistan); Dee, C. F. [Universiti Kebangsaan Malaysia (UKM), Institute of Microengineering and Nanoelectronics (IMEN) (Malaysia); Khurram, A. A. [National Centre for Physics, Quaid-i-Azam University, Experimental Physics Labs (Pakistan); Yan, L., E-mail: yanlong@sinap.ac.cn; Zhou, X. T. [Chinese Academy of Sciences, Shanghai Institute of Applied Physics (China); Nadeem, A.; Naseem, S. [University of the Punjab, Centre of Excellence in Solid State Physics (Pakistan); Rafique, H. M. [University of the Punjab, Department of Physics (Pakistan); Majlis, B. Y. [Universiti Kebangsaan Malaysia (UKM), Institute of Microengineering and Nanoelectronics (IMEN) (Malaysia)

2013-04-15

Zinc oxide (ZnO) nanowires (NWs) are exposed to energetic proton (H{sup +}), nitrogen (N{sup +}), phosphorus (P{sup +}), and argon (Ar{sup +}) ions to understand the radiation hardness and structural changes induced by these irradiations. High-resolution transmission electron microscopy is utilized to see the irradiation effects in NWs. Multiple doses and energies of radiation at different temperatures are used for different set of samples. The study reveals that wurtzite (crystalline)-structured ZnO NWs experience amorphization, degradation, and morphological changes after the irradiation. At room temperature, deterioration of the crystalline structure is observed under high fluence of H{sup +}, N{sup +}, and P{sup +} ions. While for ZnO NWs, bombarded by Ar{sup +} and P{sup +} ions, nano-holes are produced. The ZnO NWs surfaces also show corrugated morphology full of nano-humps when irradiated by Ar{sup +} ions at 400 Degree-Sign C. The corrugated surface could serve as tight-holding interface when interconnecting it with other NWs/nanotubes. These nano-humps may have the function of increasing the surface for surface-oriented sensing applications in the future.

What do facial expressions of emotion express in young children? The relationship between facial display and EMG measures

Directory of Open Access Journals (Sweden)

Michela Balconi

2014-04-01

Full Text Available The present paper explored the relationship between emotional facial response and electromyographic modulation in children when they observe facial expression of emotions. Facial responsiveness (evaluated by arousal and valence ratings and psychophysiological correlates (facial electromyography, EMG were analyzed when children looked at six facial expressions of emotions (happiness, anger, fear, sadness, surprise and disgust. About EMG measure, corrugator and zygomatic muscle activity was monitored in response to different emotional types. ANOVAs showed differences for both EMG and facial response across the subjects, as a function of different emotions. Specifically, some emotions were well expressed by all the subjects (such as happiness, anger and fear in terms of high arousal, whereas some others were less level arousal (such as sadness. Zygomatic activity was increased mainly for happiness, from one hand, corrugator activity was increased mainly for anger, fear and surprise, from the other hand. More generally, EMG and facial behavior were highly correlated each other, showing a “mirror” effect with respect of the observed faces.

On metallic gratings coated conformally with isotropic negative-phase-velocity materials

International Nuclear Information System (INIS)

Inchaussandague, Marina E.; Lakhtakia, Akhlesh; Depine, Ricardo A.

2008-01-01

Application of the differential method (also called the C method) to plane-wave diffraction by a perfectly conducting, sinusoidally corrugated metallic grating coated with a linear, homogeneous, isotropic, lossless dielectric-magnetic material shows that coating materials with negative index of refraction may deliver enhanced maximum nonspecular reflection efficiencies in comparison to coating materials with positive index of refraction

On metallic gratings coated conformally with isotropic negative-phase-velocity materials

Energy Technology Data Exchange (ETDEWEB)

Inchaussandague, Marina E. [GEA-Grupo de Electromagnetismo Aplicado, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires (Argentina); CONICET-Consejo Nacional de Investigaciones Cientificas y Tecnicas, Rivadavia 1917, Buenos Aires (Argentina)], E-mail: mei@df.uba.ar; Lakhtakia, Akhlesh [CATMAS-Computational and Theoretical Materials Sciences Group, Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, PA 16802-6812 (United States)], E-mail: akhlesh@psu.edu; Depine, Ricardo A. [GEA-Grupo de Electromagnetismo Aplicado, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires (Argentina); CONICET-Consejo Nacional de Investigaciones Cientificas y Tecnicas, Rivadavia 1917, Buenos Aires (Argentina)], E-mail: rdep@df.uba.ar

2008-03-31

Application of the differential method (also called the C method) to plane-wave diffraction by a perfectly conducting, sinusoidally corrugated metallic grating coated with a linear, homogeneous, isotropic, lossless dielectric-magnetic material shows that coating materials with negative index of refraction may deliver enhanced maximum nonspecular reflection efficiencies in comparison to coating materials with positive index of refraction.

2,6-Bis(2-hydroxyethyl-8b,8c-diphenylperhydro-2,3a,4a,6,7a,8a-hexaazacyclopenta[def]fluorene-4,8-dithione

Directory of Open Access Journals (Sweden)

Zihua Wang

2009-06-01

Full Text Available In the title molecule, C24H28N6O2S2, the dihedral angle between the aromatic ring planes is 42.2 (1°. In the crystal structure, the hydroxy groups are involved in O—H...S hydrogen bonding, which links the molecules into corrugated layers propagating parallel to the bc plane.

Plate forming and break down pizza box

Science.gov (United States)

Pantisano, Frank; Devine, Scott M.

1992-01-01

A standard corrugated paper pizza box is provided with slit cuts cut through the top panel of the pizza box in a shape to form four circular serving plates with a beveled raised edge and cross slit cuts through the bottom panel of the pizza box separating the box into four essentially equal portions for easy disposal.

Method to manufacture superconducting layers on a tubular conductor

International Nuclear Information System (INIS)

Schatz, F.; Marx, K.H.; Rohner, P.

1987-01-01

A coated tape of Cu and Nb is first made. It is already corrugated and coiled. It is then immersed in Sn, where the intermetallic compound Nb 3 Sn is formed by diffusion in the annealing furnace, and is then rashly cooled with a protective gas. The thus manufactured stabilized superconductor can be economically produced in great length. (orig./MM) [de

Rural-Urban Interdependence in Food Systems in Nsukka Local ...

African Journals Online (AJOL)

USER

by influencing the decision to migrate, remain in the rural area, or provide urban services in ..... (dried cassava) processing machines, vehicles, corrugated iron houses. A final .... It can also influence learning and adoption rates of new ..... 18.3. 8 . Palm tree. Small. 46.7. 73.3. Medium. 51.7. 3.3. Large. 1.7. None. 0.0. 23.3 ...

Nonlinear evolution of single spike in Richtmyer-Meshkov instability

International Nuclear Information System (INIS)

Fukuda, Y.; Nishihara, K.; Wouchuk, J.G.

2000-01-01

Nonlinear evolution of single spike structure and vortex in the Richtmyer-Meshkov instability is investigated with the use of a two-dimensional hydrodynamic code. It is shown that singularity appears in the vorticity left by transmitted and reflected shocks at a corrugated interface. This singularity results in opposite sign of vorticity along the interface that causes double spiral structure of the spike. (authors)

Corrugated Two-dimensional Material Enabled Flexoelectricity for Cryogenic Actuator Technology

Data.gov (United States)

National Aeronautics and Space Administration — Next generation cryogenic actuator technology (CAT) calls for a wide range of operating temperatures from -296 °C (liquid He) to 116 °C (max on moon surface)....

Numerical simulation of heat exchangers elliptical tubes and corrugated fins

International Nuclear Information System (INIS)

Borrajo Pérez, Rubén; González Bayón, Juan José; Menéndez Pérez, Alberto

2015-01-01

The intensified heat exchangers fins are widely used in the automotive and domestic industry. The low heat transfer coefficients on the air side are the main reason why these fins of heat exchangers need to be intensified. In this paper, the numerical simulation of a wavy fin type is made with elliptical tubes. The dimensions of the fin is in the range of those used in air conditioning equipment. The friction factor and the mass transfer coefficient as a function of the Reynolds number for this type of fin, always within the laminar regime is determined. The numerical model against experimental results published in the literature is validated. In addition the mechanisms that produce intensified heat transfer fin in such occur. (full text)

Facial EMG responses to emotional expressions are related to emotion perception ability.

Science.gov (United States)

Künecke, Janina; Hildebrandt, Andrea; Recio, Guillermo; Sommer, Werner; Wilhelm, Oliver

2014-01-01

Although most people can identify facial expressions of emotions well, they still differ in this ability. According to embodied simulation theories understanding emotions of others is fostered by involuntarily mimicking the perceived expressions, causing a "reactivation" of the corresponding mental state. Some studies suggest automatic facial mimicry during expression viewing; however, findings on the relationship between mimicry and emotion perception abilities are equivocal. The present study investigated individual differences in emotion perception and its relationship to facial muscle responses - recorded with electromyogram (EMG)--in response to emotional facial expressions. N° = °269 participants completed multiple tasks measuring face and emotion perception. EMG recordings were taken from a subsample (N° = °110) in an independent emotion classification task of short videos displaying six emotions. Confirmatory factor analyses of the m. corrugator supercilii in response to angry, happy, sad, and neutral expressions showed that individual differences in corrugator activity can be separated into a general response to all faces and an emotion-related response. Structural equation modeling revealed a substantial relationship between the emotion-related response and emotion perception ability, providing evidence for the role of facial muscle activation in emotion perception from an individual differences perspective.

Modulation of the startle reflex by pleasant and unpleasant music.

Science.gov (United States)

Roy, Mathieu; Mailhot, Jean-Philippe; Gosselin, Nathalie; Paquette, Sébastien; Peretz, Isabelle

2009-01-01

The issue of emotional feelings to music is the object of a classic debate in music psychology. Emotivists argue that emotions are really felt in response to music, whereas cognitivists believe that music is only representative of emotions. Psychophysiological recordings of emotional feelings to music might help to resolve the debate, but past studies have failed to show clear and consistent differences between musical excerpts of different emotional valence. Here, we compared the effects of pleasant and unpleasant musical excerpts on the startle eye blink reflex and associated body markers (such as the corrugator and zygomatic activity, skin conductance level and heart rate). The startle eye blink amplitude was larger and its latency was shorter during unpleasant compared with pleasant music, suggesting that the defensive emotional system was indeed modulated by music. Corrugator activity was also enhanced during unpleasant music, whereas skin conductance level was higher for pleasant excerpts. The startle reflex was the response that contributed the most in distinguishing pleasant and unpleasant music. Taken together, these results provide strong evidence that emotions were felt in response to music, supporting the emotivist stance.

CFD SIMULATION OF THE HEAT TRANSFER PROCESS IN A CHEVRON PLATE HEAT EXCHANGER USING THE SST TURBULENCE MODEL

Directory of Open Access Journals (Sweden)

Jan Skočilas

2015-08-01

Full Text Available This paper deals with a computational fluid dynamics (CFD simulation of the heat transfer process during turbulent hot water flow between two chevron plates in a plate heat exchanger. A three-dimensional model with the simplified geometry of two cross-corrugated channels provided by chevron plates, taking into account the inlet and outlet ports, has been designed for the numerical study. The numerical model was based on the shear-stress transport (SST k-! model. The basic characteristics of the heat exchanger, as values of heat transfer coefficient and pressure drop, have been investigated. A comparative analysis of analytical calculation results, based on experimental data obtained from literature, and of the results obtained by numerical simulation, has been carried out. The coefficients and the exponents in the design equations for the considered plates have been arranged by using simulation results. The influence on the main flow parameters of the corrugation inclination angle relative to the flow direction has been taken into account. An analysis of the temperature distribution across the plates has been carried out, and it has shown the presence of zones with higher heat losses and low fluid flow intensity.

Nonlinear effects contributing to hand-stopping tones in a horn.

Science.gov (United States)

Ebihara, Takayasu; Yoshikawa, Shigeru

2013-05-01

Hand stopping is a technique for playing the French horn while closing the bell relatively tightly using the right hand. The resulting timbre is called "penetrating" and "metallic." The effect of hand stopping on the horn input impedance has been studied, but the tone quality has hardly ever been considered. In the present paper, the dominant physical cause of the stopped-tone quality is discussed in detail. Numerical calculations of the transmission function of the stopped-horn model and the measurements of both sound pressure and wall vibration in hand stopping are carried out. They strongly suggest that the metallicness of the stopped tone is characterized by the generation of higher harmonics extending over 10 kHz due to the rapidly corrugating waveform and that the associated wall vibration on the bell may be responsible for this higher harmonic generation. However, excitation experiments and immobilization experiments performed to elucidate the relationship between sound radiation and wall vibration deny their correlation. Instead, the measurement result of the mouthpiece pressure in hand stopping suggests that minute wave corrugations peculiar to the metallic stopped tones are probably formed by nonlinear sound propagation along the bore.

Current status of ITER EC design

International Nuclear Information System (INIS)

Bosia, G.

2003-01-01

The ITER-FEAT Electron Cyclotron System employs one equatorial launcher and three upper port launchers to inject 20 + 20 MW of mm-wave power at 170 GHz through slots in the plasma-facing neutron and radiation shield. The equatorial launcher includes 3 sets of toroidally steer-able mirrors, each collecting 8 RF beams from 24 circular cross-section corrugated wave-guides. In the upper-port launcher, eight beams, reflected in pairs by four toroidally angled (∼30 angle) and poloidally steer-able (∼ 10 angle) mirrors focus of the RF power on the plasma m = 2 and m = 3/2 plasma flux rational surfaces, for neo-classical tearing mode(s) (NTM) control. Conceptual studies of remote steering that would possibly allow removing the beam- steering equipment from the vacuum vessel and locating them in more protected positions have been carried out. All EC wave transmission is based on low losses circular cross section corrugated and evacuated wave guides each connected to a 170 GHz, 1 MW CW Gyrotron tube oscillator featuring an overall efficiency of ∼ 50%, obtained by depressed-collector energy recovery. In the paper, requirements, issues and the current status of the design is reviewed. (authors)

Theory and simulation of epitaxial rotation. Light particles adsorbed on graphite

DEFF Research Database (Denmark)

Vives, E.; Lindgård, P.-A.

1993-01-01

We present a theory and Monte Carlo simulations of adsorbed particles on a corrugated substrate. We have focused on the case of rare gases and light molecules, H-2 and D2, adsorbed on graphite. The competition between the particle-particle and particle-substrate interactions gives rise to frustra...... found a modulated 4 x 4 structure. Energy, structure-factor intensities, peak positions, and epitaxial rotation angles as a function of temperature and coverage have been determined from the simulations. Good agreement with theory and experimental data is found.......We present a theory and Monte Carlo simulations of adsorbed particles on a corrugated substrate. We have focused on the case of rare gases and light molecules, H-2 and D2, adsorbed on graphite. The competition between the particle-particle and particle-substrate interactions gives rise...... between the commensurate and incommensurate phase for the adsorbed systems. From our simulations and our theory, we are, able to understand the gamma phase of D2 as an ordered phase stabilized by disorder. It can be described as a 2q-modulated structure. In agreement with the experiments, we have also...

Theoretical investigation of the Fermi surface of La2-xSrxCuO4 and YBa2Cu3O7

International Nuclear Information System (INIS)

Antonov, V.N.; Antonov, V.N.; Bar'yakhtar, V.G.

1989-01-01

The theoretical investigation of both the Fermi surface (FS) form and isoenergetic surfaces near the Fermi energy of La 2-x Sr x CuO 4 and YBa 2 Cu 3 O 7 is carried out by selfconsistent LMTO/method in an atomic sphere approximation. The FS of these compounds is established to have an essential two-dimensional character. The FS La 2 CuO 4 is a corrugated rounded box centered in Γ point. The FS YBa 2 Cu 3 O 7 consists of four plates: an electron ''cushion'' in Γ point and three embeded hole surfaces centered in S point. In this case the ''cushion'' and one of the hole surfaces are vigorously corrugated along the z-direction. A comparison between both the FS calculated theoretically of La 2 CuO 4 and YBa 2 Cu 3 O 7 and experimental data on electron-positron annihilation is carried out. The electron-rate maps and numerical results of various characteristics, i.e., plate areas, mean rates, mean squares of the rates, partial densities of states for each plate of the FS YBa 2 Cu 3 O 7 are given

Evaluations of sampling methods for darkling beetles (Alphitobius diaperinus) in the litter of turkey and broiler houses.

Science.gov (United States)

Safrit, R D; Axtell, R C

1984-12-01

Materials placed on the litter in turkey and broiler houses were evaluated as sampling devices for the larvae and adults of Alphitobius diaperinus (lesser mealworm or darkling beetle). Insects harbored in, on, and between pieces of the materials were counted after 1-week exposure. Pan traps consisting of two stacked pieces of 1.3-cm thick foil-covered polyisocyanurate insulation (Celotex) placed under a protective metal pan staked to the litter surface was a more effective sampling device than pan traps using thicker (5 cm) Celotex, 3.8 cm thick polystyrene (Styrofoam), or two stacked pieces of wood. A tube trap consisting of rolled fluted corrugated cardboard inserted in a section of polyvinyl chloride pipe was as effective a sampling device as the two pieces of Celotex in a pan trap and was more convenient to use. Six pieces of corrugated cardboard stacked under a pan caught larger numbers of beetle larvae and adults but was awkward to handle and impractical. Placement of sampling devices in the major subhabitats (open center, near walls, near feeders, and near waterers) in turkey and broiler houses affected catches of beetle larvae and adults. The open center area was satisfactory and most convenient.

An unexplained three-dimensional percept emerging from a bundle of lines.

Science.gov (United States)

Altschuler, Eric L; Huang, Abigail E; Kim, Hee J; Battaglini, Luca; Roncato, Sergio

2017-10-01

Perceptual grouping has been extensively studied, but some areas are still unexplored-in particular, the figural organizations that emerge when bundles of intersecting lines are drawn. Here, we will describe some figural organizations that emerge after the superimposition of bundles of lines forming the profile of regular triangular waves. By manipulating the lines' jaggedness and junction geometry (regular or irregular X junction) we could generate the following organizations: (a) a grid, or a figural configuration in which both the lines and closed contours are perceived, (b) a figure-ground organization composed of figures separated by portions of the background, and (c) a corrugated surface appearing as a multifaceted polyhedral shell crossed by ridges and valleys. An experiment was conducted with the aim at testing the role of the good-continuation and closure Gestalt factors. Good continuation prevails when the lines are straight or close to straightness, but its role is questionable in the appearance of a corrugated surface. This perceptual organization occurs despite the violation of the good-continuation rule and consists of a structure of such complexity so as to challenge algorithms of computer vision and stimulate a deeper understanding of the perceptual interpretation of groups of lines.

Vacuum Chamber for the Booster Bending Magnets

CERN Multimedia

CERN PhotoLab

1974-01-01

To minimize eddy currents, induced by the rising magnetic field, the chamber was made from thin stainless steel of high specific electric resistance. For mechanical stength, it was corrugated in a hydro-forming process. The chamber is curved, to follow the beam's orbital path. Under vacuum, the chamber tends to staighten, the ceramic spacer along half of its length keeps it in place (see also 7402458).

Vacuum Chamber for the Booster Bending Magnets

CERN Multimedia

CERN PhotoLab

1974-01-01

To minimise eddy currents, induced by the rising magnetic field, the chamber was made from thin stainless steel of high specific electric resistance. For mechanical strength, it was corrugated in a hydro-forming process. The cross-section was designed for maximum strength and maximum aperture. To accept particles with simultaneous large amplitudes in both planes, the cross-section approaches a rectangular shape (see also 7402463).

Spherical fusion plasma-confinement field of Surmac type

Energy Technology Data Exchange (ETDEWEB)

Wipf, S.L.

1981-01-01

The concept of a Surmac confinement field that can be completely closed is presented. The internal conductor is magnetically suspended inside large corrugations of a superconducting spherical shell structure that carries the return current. Presently available superconductor technology using superfluid helium cooling allows fields above 1.5T throughout the wall region. Such a Surmac has potential for the study of advanced fuel cycles.

Using Indigenous Materials for Construction

Science.gov (United States)

2015-07-01

block, lime, gypsum, natural pozzolans, biomass ash, vegetable fibers (and their fabrics/ropes), straw, bamboo, tree trunks/stems/leaves, corrugated...overcome the size limitation and numerical convergence, the finite element model was developed using multi-layered shell elements (unlike the...elements was used in finite element modeling of the sandwich composite panel. Shell elements were used in the case of the building system in order to

(Invited) Wavy Channel TFT Architecture for High Performance Oxide Based Displays

KAUST Repository

Hanna, Amir; Hussain, Aftab M.; Hussain, Aftab M.; Ghoneim, Mohamed T.; Rojas, Jhonathan Prieto; Sevilla, Galo T.; Hussain, Muhammad Mustafa

2015-01-01

We show the effectiveness of wavy channel architecture for thin film transistor application for increased output current. This specific architecture allows increased width of the device by adopting a corrugated shape of the substrate without any further real estate penalty. The performance improvement is attributed not only to the increased transistor width, but also to enhanced applied electric field in the channel due to the wavy architecture.

(Invited) Wavy Channel TFT Architecture for High Performance Oxide Based Displays

KAUST Repository

Hanna, Amir

2015-05-22

We show the effectiveness of wavy channel architecture for thin film transistor application for increased output current. This specific architecture allows increased width of the device by adopting a corrugated shape of the substrate without any further real estate penalty. The performance improvement is attributed not only to the increased transistor width, but also to enhanced applied electric field in the channel due to the wavy architecture.

The progress of test and study for steam dryer in vertical steam generator

International Nuclear Information System (INIS)

Ding Xunshen

1993-01-01

Constructions, tests and test results are reviewed for three types of steam generator dryer that are concentric vertical corrugated separator, centrifugal conic separator and chevron separator. The last type is considered as the best one in comparison, which has been applied to Qinshan 300 MW steam generator. A number of pertinent remarks to draining scheme, hydraulic loss reduction, and conduct of test are given based on experiences

Investigation of the surface terminations of icosahedral AlPdMn quasicrystal based on a modified non-spherical model

International Nuclear Information System (INIS)

Yu Fengmei; Zou Huamin; Wang Jianbo; Wang Renhui

2004-01-01

The atomic positions are obtained from a modified non-spherical model of icosahedral AlPdMn quasicrystal (Fang et al 2003 J. Phys.: Condens. Matter 15 4947) by the cut method. The four-shell pseudo-Mackay clusters (PMCs) were searched for in a box of 400 A x 400 A x 400 A. The results show that the number of atoms in the fourth shell, an icosidodecahedron, of the pseudo-Mackay cluster can vary from 15 to 30 because of the cluster overlap, and about 99.96% of the total atoms are included in such incomplete pseudo-Mackay clusters. The characteristics of the atom distribution in the planes perpendicular to a fivefold axis indicate that the planes, which are 1.56 A apart from their neighbouring planes, are expected to be the terminal surfaces. If one such a plane and its closest neighbouring plane, between which the spacing is 0.48 A, are considered as a thin layer or a corrugated surface, these layers are also the layers with the maximum density. The pair of corrugated surfaces that are 1.56 A apart have almost identical chemical composition. These planes form terraces that follow the rule of the Fibonacci sequence with two step heights, 6.60 and 4.08 A. On the corrugated surfaces perpendicular to a fivefold axis the pentagonal holes arise from the interspaces of adjacent incomplete PMCs. For the atomic planes normal to a twofold axis, the planes with spacing of 1.48 A from their adjacent planes might be expected to be the terminal surfaces, which form terraces with step heights of 6.28 and 3.88 A following the rule of the Fibonacci sequence. For the atomic planes normal to a threefold axis, the planes with spacing of 0.86 A from their adjacent planes might be expected to be the terminal surfaces. No similar results were found for the atomic layers perpendicular to a pseudo-twofold axis

Linear analysis of an X-band backward wave oscillator with a circular-edge disk-loaded cylindrical waveguide driven by an annular electron beam

Science.gov (United States)

Hasan Sagor, Rakibul; Ruhul Amin, Md.

2017-10-01

An X-band backward wave oscillator (BWO) with a circular-edge disk-loaded periodic metallic slow wave structure (CDSWS) is proposed and studied numerically. The structure is the modified version of our previously modeled semi-circularly corrugated slow wave structure (SCCSWS). The CDSWS is energized by an intense relativistic electron beam (IREB) which is directed by a strong magnetic field. The electromagnetic (EM) wave of the slow wave structure (SWS) merges with the space charge wave of the beam under the guidance of the strong axial magnetic field. The inner wall contour of CDSWS is modeled by a finite Fourier series and the dispersion characteristics of different TM modes are solved by utilizing the linear Rayleigh-Fourier (R-F) technique, which is verified by a commercial EM solver. To study the temporal growth rate (TGR) for the fundamental TM01 mode, the dispersion equation is solved for the beam current of 0.1-1.0kA and the beam energy of 205-665kV. For the TM01 mode, the TGR that occurs at the unstable region, which provides a qualitative index of the strength of the microwave generation, is compared with those of the BWOs with sinusoidally corrugated SWS (SCSWS), disk-loaded SWS (DLSWS) and triangularly corrugated SWS (TrCSWS) for different beam parameters. The dimension of the CDSWS is determined by comparing the dispersion characteristics of fundamental TM01 mode with DLSWS and SCSWS. For the same set of beam parameters, an average of 3.5%, 7%, 1.5% and more than 50% higher TGR have been obtained with the proposed CDSWS than that of SCSWS, DLSWS, TrCSWS and SCCSWS respectively. Moreover, the presented structure also provides an advantage in the fabrication process and is less prone to RF breakdown since it has no sharp edges in the inner wall where the electric field intensity can be infinitely high.

Design and application of environmentally effective concrete with usage of chrysotile-cement waste

OpenAIRE

Egorova Lada; Semenov Vyacheslav; Pligina Anna; Askhadullin Aizat

2016-01-01

Construction is resource-demanding industry, characterized by a large volume of waste. Particularly chrysotile cement waste obtained both in production and in dismantling over age chrysotile-cement products: corrugated asbestos boards and flat sheets, chrysotile-cement tubes. We propose to use dry chrysotile-cement waste as recycled aggregate for concrete. Based on developed compositions and identified properties of heavy concrete with chrysotile-cement waste introduce this technology to the ...

Quantum theory of atom-surface scattering: exact solutions and evaluation of approximations

International Nuclear Information System (INIS)

Chiroli, C.; Levi, A.C.

1976-01-01

In a recent article a hard corrugated surface was proposed as a simple model for atom-surface scattering. The problem was not solved exactly, however, but several alternative approximations were considered. Since these three similar, but inequivalent, approximations were proposed, the problem arose to evaluate these approximations in order to choose between them. In the present letter some exact calculations are presented which make this choice rationally possible. (Auth.)

Preliminary study of ECE imaging concept for W7-X, using the Talbot effect in rectangular waveguides

Energy Technology Data Exchange (ETDEWEB)

Iglesias, Daniel; Plaum, Burkhard; Kasparek, Walter; Hirth, Thomas [IGVP, Universitaet Stuttgart (Germany); Hirsch, Matthias [Max-Planck Institut fuer Plasmaphysik, Greifswald (Germany)

2016-07-01

For spatially resolved measurements of Electron Cyclotron Emission (ECE) in W7-X, an imaging antenna based on a corrugated rectangular waveguide can be used. The imaging characteristics of the antenna allow a simultaneous operation at multiple angles and frequencies. As a result it is possible to localize a set of points inside the plasma, where the ECE can be measured without the need of mobile components facing the plasma.

Nanoelectronics, Nanophotonics, and Nanomagnetics: Report of the National Nanotechnology Initiative Workshop February 11-13, 2004

Science.gov (United States)

2004-02-01

of Intel. Magnetic cobalt nanoparticles self-assembled into bracelet-like “ nanorings ,” courtesy of Alexander Wei and Purdue University News Service...corrugation. The concentric ring pattern was milled into a sapphire substrate, which was then overcoated with 300 nm of silver . As a final step, a...Malicka, I. Gryczynski, Z. Gryczynski, J. R. Lakowicz, Effects of fluorophore-to- silver distance on the emission of cyanine-dye-labeled

Mode converter for electron cyclotron resonance heating of toroidal plasmas

International Nuclear Information System (INIS)

Motley, R.W.; Hsuan, H.; Glanz, J.

1980-09-01

A method is proposed for improving the efficiency of cyclotron resonance heating of a toroidal plasma by ordinary mode radiation from the outside of the torus. Radiation not absorbed in the first pass is reflected from the inside of the torus by a corrugated surface which rotates the polarization by 90 0 , so that a secondary source of extraordinary waves is created in the high field, accessible region of the plasma

Environmental Assessment: Demolition of McGuire Central Heat Plant at Joint Base McGuire-Dix-Lakehurst, New Jersey

Science.gov (United States)

2012-06-01

insulation, boiler, holding tank and duct coverings, floor tiles , window caulking/glazing, and corrugated building siding. The asbestos insulation and...facility, with the Bulk Fuel Storage area and the golf course located between them. BOMARC is located several miles from the proposed solar sites...Architectural Resources The Central Heat Plant was constructed in 1956. It is a flat- roofed building originally rectangular in form, and is now L-shaped. The

Analysis of physiological responses associated with emotional changes induced by viewing video images of dental treatments.

Science.gov (United States)

Sekiya, Taki; Miwa, Zenzo; Tsuchihashi, Natsumi; Uehara, Naoko; Sugimoto, Kumiko

2015-03-30

Since the understanding of emotional changes induced by dental treatments is important for dentists to provide a safe and comfortable dental treatment, we analyzed physiological responses during watching video images of dental treatments to search for the appropriate objective indices reflecting emotional changes. Fifteen healthy young adult subjects voluntarily participated in the present study. Electrocardiogram (ECG), electroencephalogram (EEG) and corrugator muscle electromyogram (EMG) were recorded and changes of them by viewing videos of dental treatments were analyzed. The subjective discomfort level was acquired by Visual Analog Scale method. Analyses of autonomic nervous activities from ECG and four emotional factors (anger/stress, joy/satisfaction, sadness/depression and relaxation) from EEG demonstrated that increases in sympathetic nervous activity reflecting stress increase and decreases in relaxation level were induced by the videos of infiltration anesthesia and cavity excavation, but not intraoral examination. The corrugator muscle activity was increased by all three images regardless of video contents. The subjective discomfort during watching infiltration anesthesia and cavity excavation was higher than intraoral examination, showing that sympathetic activities and relaxation factor of emotion changed in a manner consistent with subjective emotional changes. These results suggest that measurement of autonomic nervous activities estimated from ECG and emotional factors analyzed from EEG is useful for objective evaluation of subjective emotion.

Fiscal 1999 achievement report on the venture business assisting type regional consortium - Minor business creation base type. Development of environmental protection oriented technology for effectively utilizing waste paper; 1999 nendo chiiki consortium kenkyu kaihatsu jigyo seika hokokusho. Kankyo hozengata no koshi no yuko riyo gijutsu no kaihatsu

Energy Technology Data Exchange (ETDEWEB)

NONE

2001-03-01

The effort aims to use low grade waste paper out of various grades of waste paper, whose recovery does not make good progress, as a raw material for the development of value-added, commercially competitive products and to contribute to the enhancement of waste paper recovery. A dry pulverization method less polluting the environment and not requiring a drying process is established, and types of waste paper and optimum conditions for their pulverization are made clear. A molding system using a steam injection method capable of atmospheric pressure control is established, and this enables the molding of pulverized waste paper not only into flat boards but also into corrugated boards. It is found that water contained in the waste paper alone produces a result similar to that expected from steam injection. A partitioning board is produced from waste paper, and it is found to be near the conventional product in terms of noise absorption. Old newspaper and corrugated cardboard are pulverized and an air filter is developed, which is similar to the conventional product in terms of operating efficiency and life. Waste paper is carbonized, and then charcoal with more pores than the conventional charcoal is produced. The porous charcoal is found to be usable in vegetable beds. (NEDO)

A Preliminary Experimental Study on Vibration Responses of Foamed Concrete Composite Slabs

Science.gov (United States)

Rum, R. H. M.; Jaini, Z. M.; Ghaffar, N. H. Abd; Rahman, N. Abd

2017-11-01

In recent years, composite slab has received utmost demand as a floor system in the construction industry. The composite slab is an economical type of structure and able to accelerate the construction process. Basically, the composite slab can be casting by using a combination of corrugated steel deck and normal concrete in which selfweight represents a very large proportion of the total action. Therefore, foamed concrete become an attractive alternative to be utilized as a replacement of normal concrete. However, foamed concrete has high flexibility due to the presence of large amount of air-void and low modulus elasticity. It may result in vibration responses being greater. Hence, this experimental study investigates the vibration responses of composite slab made of corrugated steel deck and foamed concrete. The specimens were prepared with dimension of 750mm width, 1600mm length and 125mm thickness. The hammer-impact test was conducted to obtain the acceleration-time history. The analysis revealed that the first natural frequency is around 27.97 Hz to 40.94 Hz, while the maximum acceleration reaches 1.31 m/s2 to 1.88 m/s2. The first mode shape depicts normal pattern and favourable agreement of deformation.

Numerical Study on the Projectile Impact Resistance of Multi-Layer Sandwich Panels with Cellular Cores

Directory of Open Access Journals (Sweden)

Liming Chen

Full Text Available Abstract The projectile impact resistance of sandwich panels with cellular cores with different layer numbers has been numerically investigated by perpendicular impact of rigid blunt projectile in ABAQUS/Explicit. These panels with corrugation, hexagonal honeycomb and pyramidal truss cores are impacted at velocities between 50 m/s and 202 m/s while the relative density ranges from 0.001 to 0.15 The effects of core configuration and layer number on projectile impact resistance of sandwich panels with cellular cores are studied. At low impact velocity, sandwich panels with cellular cores outperform the corresponding solid ones and non-montonicity between relative density and projectile resistance of sandwich panels is found and analyzed. Multiplying layer can reduce the maximum central deflection of back face sheet of the above three sandwich panels except pyramidal truss ones in high relative density. Hexagonal honeycomb sandwich panel is beneficial to increasing layer numbers in lowering the contact force and prolonging the interaction time. At high impact velocity, though corrugation and honeycomb sandwich panels are inferior to the equal-weighted solid panels, pyramidal truss ones with high relative density outperform the corresponding solid panels. Multiplying layer is not the desirable way to improve high-velocity projectile resistance.

Integral Design Methodology of Photocatalytic Reactors for Air Pollution Remediation

Directory of Open Access Journals (Sweden)

Claudio Passalía

2017-06-01

Full Text Available An integral reactor design methodology was developed to address the optimal design of photocatalytic wall reactors to be used in air pollution control. For a target pollutant to be eliminated from an air stream, the proposed methodology is initiated with a mechanistic derived reaction rate. The determination of intrinsic kinetic parameters is associated with the use of a simple geometry laboratory scale reactor, operation under kinetic control and a uniform incident radiation flux, which allows computing the local superficial rate of photon absorption. Thus, a simple model can describe the mass balance and a solution may be obtained. The kinetic parameters may be estimated by the combination of the mathematical model and the experimental results. The validated intrinsic kinetics obtained may be directly used in the scaling-up of any reactor configuration and size. The bench scale reactor may require the use of complex computational software to obtain the fields of velocity, radiation absorption and species concentration. The complete methodology was successfully applied to the elimination of airborne formaldehyde. The kinetic parameters were determined in a flat plate reactor, whilst a bench scale corrugated wall reactor was used to illustrate the scaling-up methodology. In addition, an optimal folding angle of the corrugated reactor was found using computational fluid dynamics tools.

Abnormal flow behavior and necklace microstructure of powder metallurgy superalloys with previous particle boundaries (PPBs)

Energy Technology Data Exchange (ETDEWEB)

Ning, Yongquan, E-mail: luckyning@nwpu.edu.cn [School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072 (China); Zhou, Cong; Liang, Houquan [School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072 (China); Fu, M.W., E-mail: mmmwfu@polyu.edu.hk [Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong (China)

2016-01-15

Powder metallurgy (P/M) has been introduced as an innovative process to manufacture high performance components with fine, homogenous and segregation-free microstructure. Unfortunately, previous particle boundary (PPB) precipitated during the powder metallurgy process. Since undesirable PPB is detrimental to mechanical properties, hot extrusion or/and isothermal forging are needed. In present research, isothermal compression tests were conducted on P/M FGH4096 superalloys with typical PPBs. Abnormal flow behavior during high-speed deformation has been quantitatively investigated. Caused by the competition mechanism between work-hardening and dynamic-softening, abnormal flow behaves typical four stages (viz., work-hardening, stable, softening and steady). Microstructure observation for hardening or/and softening mechanism has been investigated. Meanwhile, necklace microstructure was observed by scanning electron microscope, and the grain fraction analysis was performed by using electron backscatter diffraction. Transmission electron microscopy was used for characterizing the boundary structure. Necklace microstructural mechanism for processing P/M superalloys has been developed, and the dynamic recrystallization model has also been conducted. Bulge–corrugation model is the primary nucleation mechanism for P/M superalloys with PPBs. When PPB is entirely covered with new grains, necklace microstructure has formed. Bulge–corrugation mechanism can repeatedly take place in the following necklace DRX.

Design of a remote steering antenna for ECRH heating in the stellarator Wendelstein 7-X

Energy Technology Data Exchange (ETDEWEB)

Plaum, B., E-mail: plaum@igvp.uni-stuttgart.de [Institut für Grenzflächenverfahrenstechnik und Plasmatechnologie (IGVP), Univ. Stuttgart, Pfaffenwaldring 31, D-70569 Stuttgart (Germany); Lechte, C.; Kasparek, W.; Gaiser, S.; Zeitler, A. [Institut für Grenzflächenverfahrenstechnik und Plasmatechnologie (IGVP), Univ. Stuttgart, Pfaffenwaldring 31, D-70569 Stuttgart (Germany); Erckmann, V. [Max-Planck-Institut für Plasmaphysik, EURATOM-IPP, D-17491 Greifswald (Germany); Weißgerber, M. [Max-Planck-Institut für Plasmaphysik, EURATOM-IPP, D-85748 Garching (Germany); Bechtold, A. [NTG Neue Technologie GmbH & Co KG, D-63571 Gelnhausen (Germany); Busch, M.; Szcepaniak, B. [Galvano-T electroplating-electroforming GmbH, D-51570 Windeck-Rosbach (Germany)

2015-10-15

Highlights: • We report about the design activities for the remote steering antennas for the stellarator W7-X. • The integration into the W7-X system and the manufacturing procedure are described. • Simulations and loss measurements for the waveguide walls were done and are in good agreement. • A method for extending the steering range is presented. • A mechanical deformation analysis showed that the deformation is not critical for the beam quality. - Abstract: For the ECRH heating system of the stellarator Wendelstein 7-X, two remote steering antennas are developed and manufactured. The principle of remote steering antennas is based on the imaging characteristics of corrugated rectangular waveguides, which is well understood and can accurately be simulated. Several details, however, require deeper investigation. The antenna needs a miter-bend and a 24 mm gap. The positions of these elements need to be chosen carefully to reduce losses and stray radiation. The antennas are manufactured from copper by electroforming. This allows to integrate all components, including the corrugated inner walls and the cooling channels, in one vacuum-tight piece. This paper reviews the design process of the remote steering antennas for W7-X as well as technological issues and experimental results from test pieces.

Spectrophotometric Method for the Determination of Atmospheric Cr Pollution as a Factor to Accelerated Corrosion

Directory of Open Access Journals (Sweden)

Dereje Homa

2017-01-01

Full Text Available The effect of Cr(VI pollution on the corrosion rate of corrugated iron roof samples collected from tanning industry areas was investigated through simulated laboratory exposure and spectrophotometric detection of Cr(III deposit as a product of the reaction. The total level of Cr detected in the samples ranged from 113.892 ± 0.17 ppm to 53.05 ± 0.243 ppm and showed increasing trend as sampling sites get closer to the tannery and in the direction of tannery effluent stream. The laboratory exposure of a newly manufactured material to a simulated condition showed a relatively faster corrosion rate in the presence of Cr(VI with concomitant deposition of Cr(III under pH control. A significant (P = 0.05 increase in the corrosion rate was also recorded when exposing scratched or stress cracked samples. A coupled redox process where Cr(VI is reduced to a stable, immobile, and insoluble Cr(III accompanying corrosion of the iron is proposed as a possible mechanism leading to the elevated deposition of the latter on the materials. In conclusion, the increased deposits of Cr detected in the corrugated iron roof samples collected from tanning industry zones suggested possible atmospheric Cr pollution as a factor to the accelerated corrosion of the materials.

Facial reactions to violent and comedy films: Association with callous-unemotional traits and impulsive aggression.

Science.gov (United States)

Fanti, Kostas A; Kyranides, Melina Nicole; Panayiotou, Georgia

2017-02-01

The current study adds to prior research by investigating specific (happiness, sadness, surprise, disgust, anger and fear) and general (corrugator and zygomatic muscle activity) facial reactions to violent and comedy films among individuals with varying levels of callous-unemotional (CU) traits and impulsive aggression (IA). Participants at differential risk of CU traits and IA were selected from a sample of 1225 young adults. In Experiment 1, participants (N = 82) facial expressions were recorded while they watched violent and comedy films. Video footage of participants' facial expressions was analysed using FaceReader, a facial coding software that classifies facial reactions. Findings suggested that individuals with elevated CU traits showed reduced facial reactions of sadness and disgust to violent films, indicating low empathic concern in response to victims' distress. In contrast, impulsive aggressors produced specifically more angry facial expressions when viewing violent and comedy films. In Experiment 2 (N = 86), facial reactions were measured by monitoring facial electromyography activity. FaceReader findings were verified by the reduced facial electromyography at the corrugator, but not the zygomatic, muscle in response to violent films shown by individuals high in CU traits. Additional analysis suggested that sympathy to victims explained the association between CU traits and reduced facial reactions to violent films.

Optical analysis and performance evaluation of a solar parabolic dish concentrator

Directory of Open Access Journals (Sweden)

Pavlović Saša R.

2016-01-01

Full Text Available In this study, the optical design of a solar parabolic dish concentrator is presented. The parabolic dish concentrator consists from 11 curvilinear trapezoidal reflective petals made of polymethyl methacrylate with special reflective coating. The dish diameter is equal to 3.8 m and the theoretical focal point distance is 2.26 m. Numerical simulations are made with the commercial software TracePro from Lambda Research, USA, and the final optimum position between absorber and reflector was calculated to 2.075 m; lower than focus distance. This paper presents results for the optimum position and the optimum diameter of the receiver. The decision for selecting these parameters is based on the calculation of the total flux over the flat and corrugated pipe receiver surface; in its central region and in the peripheral region. The simulation results could be useful reference for designing and optimizing of solar parabolic dish concentrators as for as for CFD analysis, heat transfer and fluid flow analysis in corrugated spiral heat absorbers. [Projekat Ministarstva nauke Republike Srbije, br. III42006: Research and development of energy and environmentally highly effective polygeneration systems based on renewable energy resources i br. III45016: Fabrication and characterization of nanophotonic functional structures in biomedicine and informatics

MHD STABILITY OF INTERSTELLAR MEDIUM PHASE TRANSITION LAYERS. I. MAGNETIC FIELD ORTHOGONAL TO FRONT

International Nuclear Information System (INIS)

Stone, Jennifer M.; Zweibel, Ellen G.

2009-01-01

We consider the scenario of a magnetic field orthogonal to a front separating two media of different temperatures and densities, such as cold and warm neutral interstellar gas, in a two-dimensional plane-parallel geometry. A linear stability analysis is performed to assess the behavior of both evaporation and condensation fronts when subject to incompressible, corrugational perturbations with wavelengths larger than the thickness of the front. We discuss the behavior of fronts in both super-Alfvenic and sub-Alfvenic flows. Since the propagation speed of fronts is slow in the interstellar medium (ISM), it is the sub-Alfvenic regime that is relevant, and magnetic fields are a significant influence on front dynamics. In this case, we find that evaporation fronts, which are unstable in the hydrodynamic regime, are stabilized. Condensation fronts are unstable, but for parameters typical of the neutral ISM the growth rates are so slow that steady-state fronts are effectively stable. However, the instability may become important if condensation proceeds at a sufficiently fast rate. This paper is the first in a series exploring the linear and nonlinear effects of magnetic field strength and orientation on the corrugational instability, with the ultimate goal of addressing outstanding questions about small-scale ISM structure.

A low-angle detachment fault revealed: Three-dimensional images of the S-reflector fault zone along the Galicia passive margin

Science.gov (United States)

Schuba, C. Nur; Gray, Gary G.; Morgan, Julia K.; Sawyer, Dale S.; Shillington, Donna J.; Reston, Tim J.; Bull, Jonathan M.; Jordan, Brian E.

2018-06-01

A new 3-D seismic reflection volume over the Galicia margin continent-ocean transition zone provides an unprecedented view of the prominent S-reflector detachment fault that underlies the outer part of the margin. This volume images the fault's structure from breakaway to termination. The filtered time-structure map of the S-reflector shows coherent corrugations parallel to the expected paleo-extension directions with an average azimuth of 107°. These corrugations maintain their orientations, wavelengths and amplitudes where overlying faults sole into the S-reflector, suggesting that the parts of the detachment fault containing multiple crustal blocks may have slipped as discrete units during its late stages. Another interface above the S-reflector, here named S‧, is identified and interpreted as the upper boundary of the fault zone associated with the detachment fault. This layer, named the S-interval, thickens by tens of meters from SE to NW in the direction of transport. Localized thick accumulations also occur near overlying fault intersections, suggesting either non-uniform fault rock production, or redistribution of fault rock during slip. These observations have important implications for understanding how detachment faults form and evolve over time. 3-D seismic reflection imaging has enabled unique insights into fault slip history, fault rock production and redistribution.

Facial EMG responses to emotional expressions are related to emotion perception ability.

Directory of Open Access Journals (Sweden)

Janina Künecke

Full Text Available Although most people can identify facial expressions of emotions well, they still differ in this ability. According to embodied simulation theories understanding emotions of others is fostered by involuntarily mimicking the perceived expressions, causing a "reactivation" of the corresponding mental state. Some studies suggest automatic facial mimicry during expression viewing; however, findings on the relationship between mimicry and emotion perception abilities are equivocal. The present study investigated individual differences in emotion perception and its relationship to facial muscle responses - recorded with electromyogram (EMG--in response to emotional facial expressions. N° = °269 participants completed multiple tasks measuring face and emotion perception. EMG recordings were taken from a subsample (N° = °110 in an independent emotion classification task of short videos displaying six emotions. Confirmatory factor analyses of the m. corrugator supercilii in response to angry, happy, sad, and neutral expressions showed that individual differences in corrugator activity can be separated into a general response to all faces and an emotion-related response. Structural equation modeling revealed a substantial relationship between the emotion-related response and emotion perception ability, providing evidence for the role of facial muscle activation in emotion perception from an individual differences perspective.

Predicting Pulsar Scintillation from Refractive Plasma Sheets

Science.gov (United States)

Simard, Dana; Pen, Ue-Li

2018-05-01

The dynamic and secondary spectra of many pulsars show evidence for long-lived, aligned images of the pulsar that are stationary on a thin scattering sheet. One explanation for this phenomenon considers the effects of wave crests along sheets in the ionized interstellar medium, such as those due to Alfvén waves propagating along current sheets. If these sheets are closely aligned to our line-of-sight to the pulsar, high bending angles arise at the wave crests and a selection effect causes alignment of images produced at different crests, similar to grazing reflection off of a lake. Using geometric optics, we develop a simple parameterized model of these corrugated sheets that can be constrained with a single observation and that makes observable predictions for variations in the scintillation of the pulsar over time and frequency. This model reveals qualitative differences between lensing from overdense and underdense corrugated sheets: Only if the sheet is overdense compared to the surrounding interstellar medium can the lensed images be brighter than the line-of-sight image to the pulsar, and the faint lensed images are closer to the pulsar at higher frequencies if the sheet is underdense, but at lower frequencies if the sheet is overdense.

Diffusive charge transport in graphene on SiO 2

Science.gov (United States)

Chen, J.-H.; Jang, C.; Ishigami, M.; Xiao, S.; Cullen, W. G.; Williams, E. D.; Fuhrer, M. S.

2009-07-01

We review our recent work on the physical mechanisms limiting the mobility of graphene on SiO 2. We have used intentional addition of charged scattering impurities and systematic variation of the dielectric environment to differentiate the effects of charged impurities and short-range scatterers. The results show that charged impurities indeed lead to a conductivity linear in density ( σ(n)∝n) in graphene, with a scattering magnitude that agrees quantitatively with theoretical estimates; increased dielectric screening reduces the scattering from charged impurities, but increases the scattering from short-range scatterers. We evaluate the effects of the corrugations (ripples) of graphene on SiO 2 on transport by measuring the height-height correlation function. The results show that the corrugations cannot mimic long-range (charged impurity) scattering effects, and have too small an amplitude-to-wavelength ratio to significantly affect the observed mobility via short-range scattering. Temperature-dependent measurements show that longitudinal acoustic phonons in graphene produce a resistivity that is linear in temperature and independent of carrier density; at higher temperatures, polar optical phonons of the SiO 2 substrate give rise to an activated, carrier density-dependent resistivity. Together the results paint a complete picture of charge carrier transport in graphene on SiO 2 in the diffusive regime.

Joint seal in tank

International Nuclear Information System (INIS)

Colquhoun, J.; White, G.V.

1981-01-01

A seal for a joint or gap between edges of adjacent wall sections (e.g. of concrete) of a liquid-containing vessel, such as a nuclear reactor cooling pond, comprises a sheet metal strip having longitudinally-extending edge parts, secured to the respective vessel-section edges, and a central part which is longitudinally corrugated to provide sufficient flexibility to accommodate slight relative movements between the vessel-section edges (e.g. due to thermal expansions). The edges of the sheet metal of the strip are turned in so that the edge parts of the strip are formed as generally U-section channels. These accommodate longitudinally extending securing bars which are bolted to the vessel wall sections by bolts which pass through the bars, through the free-edged wall of the channel section and through a longitudinally extending resilient seal pad compressed between that wall of the channel section and the vessel wall section to which it is secured. The other wall of the channel section (integral with the corrugated central part of the strip) has access windows through which the bolts are inserted and tightened, the windows being then closed off in liquid-tight manner by welding closure caps over them. (author)

Thin-walled composite tubes using fillers subjected to quasistatic axial compression

International Nuclear Information System (INIS)

AL-Qrimli, Haidar F; Mahdi, Fadhil A; Ismail, Firas B; Alzorqi, Ibrahim S

2015-01-01

It has been demonstrated that composites are lightweight, fatigue resistant and easily melded, a seemingly attractive alternative to metals. However, there has been no widespread switch from metals to composites in the automotive sector. This is because there are a number of technical issues relating to the use of composite materials that still need to be resolved including accurate material characterization, manufacturing and joining process. The total of 36 specimens have been fabricated using the fibre-glass and resin (epoxy) with a two different geometries (circular and corrugated) each one will be filled with five types of filler (Rice Husk, Wood Chips, Aluminium Chips, Coconut Fibre, Palm Oil Fibre) all these type will be compared with empty Tubes for circular and corrugated in order to comprehend the crashworthiness parameters (initial failure load, average load, maximum crushing load, load ratio, energy absorption, specific energy absorption, volumetric energy absorption, crushing force efficiency and crush strain relation) which are considered very sufficient parameters in the design of automotive industry parts. All the tests have been done using the “INSTRON Universal machine” which is computerized in order to simply give a high precision to the collection of the results, along with the use of quasi-static load to test and observe the behaviour of the fabricated specimens. (paper)

Thin-walled composite tubes using fillers subjected to quasistatic axial compression

Science.gov (United States)

AL-Qrimli, Haidar F.; Mahdi, Fadhil A.; Ismail, Firas B.; Alzorqi, Ibrahim S.

2015-04-01

It has been demonstrated that composites are lightweight, fatigue resistant and easily melded, a seemingly attractive alternative to metals. However, there has been no widespread switch from metals to composites in the automotive sector. This is because there are a number of technical issues relating to the use of composite materials that still need to be resolved including accurate material characterization, manufacturing and joining process. The total of 36 specimens have been fabricated using the fibre-glass and resin (epoxy) with a two different geometries (circular and corrugated) each one will be filled with five types of filler (Rice Husk, Wood Chips, Aluminium Chips, Coconut Fibre, Palm Oil Fibre) all these type will be compared with empty Tubes for circular and corrugated in order to comprehend the crashworthiness parameters (initial failure load, average load, maximum crushing load, load ratio, energy absorption, specific energy absorption, volumetric energy absorption, crushing force efficiency and crush strain relation) which are considered very sufficient parameters in the design of automotive industry parts. All the tests have been done using the “INSTRON Universal machine” which is computerized in order to simply give a high precision to the collection of the results, along with the use of quasi-static load to test and observe the behaviour of the fabricated specimens.

Spectrophotometric Method for the Determination of Atmospheric Cr Pollution as a Factor to Accelerated Corrosion.

Science.gov (United States)

Homa, Dereje; Haile, Ermias; Washe, Alemayehu P

2017-01-01

The effect of Cr(VI) pollution on the corrosion rate of corrugated iron roof samples collected from tanning industry areas was investigated through simulated laboratory exposure and spectrophotometric detection of Cr(III) deposit as a product of the reaction. The total level of Cr detected in the samples ranged from 113.892 ± 0.17 ppm to 53.05 ± 0.243 ppm and showed increasing trend as sampling sites get closer to the tannery and in the direction of tannery effluent stream. The laboratory exposure of a newly manufactured material to a simulated condition showed a relatively faster corrosion rate in the presence of Cr(VI) with concomitant deposition of Cr(III) under pH control. A significant ( P = 0.05) increase in the corrosion rate was also recorded when exposing scratched or stress cracked samples. A coupled redox process where Cr(VI) is reduced to a stable, immobile, and insoluble Cr(III) accompanying corrosion of the iron is proposed as a possible mechanism leading to the elevated deposition of the latter on the materials. In conclusion, the increased deposits of Cr detected in the corrugated iron roof samples collected from tanning industry zones suggested possible atmospheric Cr pollution as a factor to the accelerated corrosion of the materials.

SOUDAN 2 nuclear decay experiment. Progress report

International Nuclear Information System (INIS)

Minnesota; Argonne; Oxford; Rutherford; Tufts Collaboration.

1984-01-01

Construction of the experiment cavern on the 27th level of the SOUDAN iron mine in northern Minnesota began early this year and will be complete early in 1985. The first 1200 tons of the detector itself is also under construction in the US and UK; installation will begin in mid 1985. Physics exploitation will begin early in 1986 and the first 1200 ton module will be complete early in 1987. The detector may be expanded to between 3 and 5 such modules in the cavern. The detector is an iron tracking calorimeter (rho = 2) consisting of stacks of corrugated steel sheets each 1.2 mm thick. The corrugations form hexagonal channels 1 m long and 16 mm in diameter. A uniform electric field along these channels is provided by the voltage grading arising from the constant standing current in the Hytrel tubes (rho = 2 x 10 12 Ω cm) that line each channel. The tubes are insulated from the steel by sheets of mylar. Ionization in the gas in the tubes drifts in the uniform field to the end of the tube where it is amplified linearly and detected by a matrix of anode wires and cathode strips. The electronics registers both the drift time and the pulse height of all signals

N,N-Diethyl-4-[(E-(pyridin-3-yldiazenyl]aniline

Directory of Open Access Journals (Sweden)

Tatiana V. Timofeeva

2013-08-01

Full Text Available The molecule of the title compound, C15H18N4, adopts a trans conformation with respect to the diazo N=N bond. The dihedral angle between the benzene and pyridine rings in the molecule is 8.03 (5°. In the crystal, a weak C—H...π interaction arranges the molecules into a corrugated ribbon, with an antiparallel orientation of neighboring molecules propagating in the [100] direction.

Crystal structure of 3-methyl-1-phenyl-5-(1H-pyrrol-1-yl-1H-pyrazole-4-carbaldehyde

Directory of Open Access Journals (Sweden)

Joel T. Mague

2014-10-01

Full Text Available In the title compound, C15H13N3O, the pyrrolyl and phenyl rings make dihedral angles of 58.99 (5 and 34.95 (5°, respectively, with the central pyrazole ring. In the crystal, weak, pairwise C—H...O interactions across centers of symmetry form dimers, which are further associated into corrugated sheets running approximately parallel to (100 via weak C—H...N interactions.

Packaging Printing Today

OpenAIRE

Stanislav Bolanča; Igor Majnarić; Kristijan Golubović

2015-01-01

Printing packaging covers today about 50% of all the printing products. Among the printing products there are printing on labels, printing on flexible packaging, printing on folding boxes, printing on the boxes of corrugated board, printing on glass packaging, synthetic and metal ones. The mentioned packaging are printed in flexo printing technique, offset printing technique, intaglio halftone process, silk – screen printing, ink ball printing, digital printing and hybrid printing process. T...

Metasurface Waveguides Applied to Matched Feeds for Reflector Antennas

DEFF Research Database (Denmark)

Palvig, Michael Forum; Jorgensen, Erik; Meincke, Peter

2017-01-01

at different speeds than the fundamental mode in conventional waveguides, it is challenging to meet phase relationship requirements over a large band. We have found that traditional corrugated waveguides are poorly suited for matched feed applications. However, other surfaces that satisfy the balanced hybrid...... condition, but have a small capacitive longitudinal reactance and large inductive azimuthal reactance show very promising properties: In a large band, HE11 and HE21 have similar propagation characteristics....

Morphological and Structural Aspects of the Extremely Halophilic Archaeon Haloquadratum walsbyi

OpenAIRE

Sublimi Saponetti, Matilde; Bobba, Fabrizio; Salerno, Grazia; Scarfato, Alessandro; Corcelli, Angela; Cucolo, Annamaria

2011-01-01

Ultrathin square cell Haloquadratum walsbyi from the Archaea domain are the most abundant microorganisms in the hypersaline water of coastal salterns and continental salt lakes. In this work, we explore the cell surface of these microorganisms using amplitude-modulation atomic-force microscopy in nearly physiological conditions. We demonstrate the presence of a regular corrugation with a periodicity of 16-20 nm attributed to the surface layer (S-layer) protein lattice, striped domains asymmet...

Kinetic energy absorbing pad

International Nuclear Information System (INIS)

Bricmont, R.J.; Hamilton, P.A.; Ming Long Ting, R.

1981-01-01

Reactors, fuel processing plants etc incorporate pipes and conduits for fluids under high pressure. Fractures, particularly adjacent to conduit elbows, produce a jet of liquid which whips the broken conduit at an extremely high velocity. An enormous impact load would be applied to any stationary object in the conduit's path. The design of cellular, corrugated metal impact pads to absorb the kinetic energy of the high velocity conduits is given. (U.K.)

Design Criteria for Process Wastewater Pretreatment Facilities

Science.gov (United States)

1988-05-01

Stripping Column H13 ’Re Purpose: The purpose of this report, is to provide design criteria for pretreatment needs for ’ I. INTRODUCTION ’". discharge of...which a portion of the vessel is filled with packing. Packing materials vary from corrugated steel to bundles of fibers (Langdon et al., 1972) to beds...concentration(s) using Table 20. Wastewater treatability studies should be considered as a process-screening tool for all wastewater streams for

Atomic-scale Studies of Uranium Oxidation and Corrosion by Water Vapour

OpenAIRE

T. L. Martin; C. Coe; P. A. J. Bagot; P. Morrall; G. D. W Smith; T. Scott; M. P. Moody

2016-01-01

Understanding the corrosion of uranium is important for its safe, long-term storage. Uranium metal corrodes rapidly in air, but the exact mechanism remains subject to debate. Atom Probe Tomography was used to investigate the surface microstructure of metallic depleted uranium specimens following polishing and exposure to moist air. A complex, corrugated metal-oxide interface was observed, with approximately 60 at.% oxygen content within the oxide. Interestingly, a very thin (∼5 nm) interfacia...

Long-drift calorimeter modules for the Soudan 2 nucleon decay detector

International Nuclear Information System (INIS)

Hoftiezer, J.

1985-01-01

The first full size 5-ton detector modules for the Soudan 2 nucleon decay experiment have been assembled and operated. Modules consist of a hexagonal array of drift tubes and corrugated steel, instrumented to read out three-dimensional track positions and pulse height. These will be assembled to form an isotropic, continuously sensitive, self-triggering detector. Details of the design, construction, operation and performance of the modules are discussed. 7 refs., 10 figs

Distributed feedback laser amplifiers combining the functions of amplifiers and channel filters

DEFF Research Database (Denmark)

Wang, Z.; Durhuus, T.; Mikkelsen, Benny

1994-01-01

A dynamic model for distributed feedback amplifiers, including the mode coupled equations and the carrier rate equation, is established. The presented mode coupled equations have taken into account the interaction between fast changing optical signal and the waveguide with corrugations. By showin...... the possibility of amplifying 100 ps pulses without pulse broadening, we anticipate that a distributed feedback amplifier can be used as a combined amplifier and channel filter in high bit rate transmission systems....

Pressure measurements in harsh environments

International Nuclear Information System (INIS)

Cook, C.W.; Ames, E.S.

1979-01-01

A fluid coupled plate (FCP) gage was designed which allows pressure measurements to be made in harsh environments (including debris) using conventional pressure transducers. The pressure transducer is isolated by means of a rigid force plate which is supported by a bellows having one corrugation. This portion of the gage is machined from a single piece of material. The interior of the gage is filled with a phenol fluid which has a low compressibility

EVALUATION OF LINERBOARD PROPERTIES FROM MALAYSIAN CULTIVATED KENAF SODA-ANTHRAQUINONE PULPS VERSUS COMMERCIAL PULPS

OpenAIRE

Ahmad Azizi Mossello; Jalaluddin Harun; Rushdan Ibrahim; Hossien Resalati; Seyed Rashid Fallah Shamsi; Paridah Md Tahir; Mohd Nor Mohad Yusoff

2010-01-01

Malaysian cultivated kenaf has been identified as a suitable raw material for linerboard production. This study examines the soda-antraquinone (soda-AQ) pulp of kenaf fibers versus old corrugated container (OCC) and unbleached softwood kraft pulps as the main sources for linerboard production. The results showed significant differences among the pulp properties. The unbleached kraft pulp with very high freeness required high beating to reach an optimized freeness and produced paper with the h...

Contact-angle hysteresis on periodic microtextured surfaces: Strongly corrugated liquid interfaces.

Science.gov (United States)

Iliev, Stanimir; Pesheva, Nina

2016-06-01

We study numerically the shapes of a liquid meniscus in contact with ultrahydrophobic pillar surfaces in Cassie's wetting regime, when the surface is covered with identical and periodically distributed micropillars. Using the full capillary model we obtain the advancing and the receding equilibrium meniscus shapes when the cross-sections of the pillars are both of square and circular shapes, for a broad interval of pillar concentrations. The bending of the liquid interface in the area between the pillars is studied in the framework of the full capillary model and compared to the results of the heterogeneous approximation model. The contact angle hysteresis is obtained when the three-phase contact line is located on one row (block case) or several rows (kink case) of pillars. It is found that the contact angle hysteresis is proportional to the line fraction of the contact line on pillars tops in the block case and to the surface fraction for pillar concentrations 0.1-0.5 in the kink case. The contact angle hysteresis does not depend on the shape (circular or square) of the pillars cross-section. The expression for the proportionality of the receding contact angle to the line fraction [Raj et al., Langmuir 28, 15777 (2012)LANGD50743-746310.1021/la303070s] in the case of block depinning is theoretically substantiated through the capillary force, acting on the solid plate at the meniscus contact line.

Excitation of a double corrugation slow-wave structure in terahertz range

DEFF Research Database (Denmark)

Zhurbenko, Vitaliy; Krozer, Viktor; Kotiranta, Mikko

2011-01-01

In spite of the fact that the technology is constantly advancing, the realization of terahertz components is still heavily constrained by problems arising from technological limitations. As a result, the design of terahertz components still remains a challenging problem. In this work, an excitati...

Self-assembly of Ge quantum dots on periodically corrugated Si surfaces

International Nuclear Information System (INIS)

Buljan, M.; Jerčinović, M.; Radić, N.; Facsko, S.; Baehtz, C.; Muecklich, A.; Grenzer, J.; Delač Marion, I.; Mikšić Trontl, V.; Kralj, M.; Holý, V.

2015-01-01

The fabrication of regularly ordered Ge quantum dot arrays on Si surfaces usually requires extensive preparation processing, ensuring clean and atomically ordered substrates, while the ordering parameters are quite limited by the surface properties of the substrate. Here, we demonstrate a simple method for fabrication of ordered Ge quantum dots with highly tunable ordering parameters on rippled Si surfaces. The ordering is achieved by magnetron sputter deposition, followed by an annealing in high vacuum. We show that the type of ordering and lattice vector parameters of the formed Ge quantum dot lattice are determined by the crystallographic properties of the ripples, i.e., by their shape and orientation. Moreover, the ordering is achieved regardless the initial amorphisation of the ripples surface and the presence of a thin oxide layer

On the theory of turbulent flame velocity

OpenAIRE

Bychkov, Vitaly; Akkerman, Vyacheslav; Petchenko, Arkady

2012-01-01

The renormalization ideas of self-similar dynamics of a strongly turbulent flame front are applied to the case of a flame with realistically large thermal expansion of the burning matter. In that case a flame front is corrugated both by external turbulence and the intrinsic flame instability. The analytical formulas for the velocity of flame propagation are obtained. It is demonstrated that the flame instability is of principal importance when the integral turbulent length scale is much large...

Crystal structure of N-[(E-(1,3-benzodioxol-5-ylmethylidene]-4-chloroaniline

Directory of Open Access Journals (Sweden)

J. Pablo García-Merinos

2014-11-01

Full Text Available In the title compound, C14H10ClNO2, obtained by the condensation of 4-chloroaniline and piperonal, the five-membered ring is almost planar (r.m.s. deviation = 0.023 Å and the dihedral angle between the aromatic rings is 43.22 (14°. In the crystal, a short O...Cl contact of 3.173 (2 Å is observed. The molecules are arranged into corrugated (010 layers.

International Semiconductor Laser Conference. Held in Boston, Massachusetts on August 29 - September 1, 1988

Science.gov (United States)

1988-11-01

gastronomically rewarding. Excellent restaurants serving seafood, "natural-foods’, and European and Asian dishes are everywhere. A baseball game at nearby...Laboratories, Holmdel, NJ, USA .......... 6-7 A:4 9:00 am DFB Lasers with a Crescent-Shaped Active Layer on a Corrugated p-type Substrate Y Ogawa, H. Horikawa...Berkeley, CA, USA ; W.M. Clark Jr., E.H. Stevens and MW Utlaut, Hughes Research Laboratories, Malibu, CA, USA .. 12-13 A:7 9:45 am Nanosecond Wavelength

Numerical computations of the Lennard-Jones resonances and ''relative displacements'' of the scattered atomic beams from the system He/LiF(001)

International Nuclear Information System (INIS)

Garcia, N.

1976-01-01

This paper considers the effect of the attractive part of the interaction potential on the scattering of He atoms from a LiF(001) surface. We calculate, in particular, the Lennard-Jones resonances on the intensities and the phases of the scattered amplitudes, using a square well in the front of a hard corrugated surface model. We show that the amplitudes for incident energies smaller than the depth of the well are dominated by the resonances

Work on the high voltage platform of the pre-injector of PS Linac 1

CERN Multimedia

1974-01-01

Henry Charmot adjusting the electronics of the ion source on a platform which, during operation, was at 520 kV to ground. The cage containing the electronics is opened by hydraulic jacks. Visible on the left is the ion source (pill box structure) attached to the corrugated acceleration column, where the protons pass from 520 kV to ground potential. See 7403120 and for more details on the pre-injector see 7403064X and 7403066X.

Simulation of leakage through mechanical sealing device

Science.gov (United States)

Tikhomorov, V. P.; Gorlenko, O. A.; Izmerov, M. A.

2018-03-01

The procedure of mathematical modeling of leakage through the mechanical seal taking into account waviness and roughness is considered. The percolation process is represented as the sum of leakages through a gap between wavy surfaces and percolation through gaps formed by fractal roughness, i.e. the total leakage is determined by the slot model and filtration leakage. Dependences of leaks on the contact pressure of corrugated and rough surfaces of the mechanical seal elements are presented.

Coupled Acoustic-Mechanical Bandgaps

DEFF Research Database (Denmark)

Jensen, Jakob Søndergaard; Kook, Junghwan

2016-01-01

medium and the presence of acoustic resonances. It is demonstrated that corrugation of the plate structure can introduce bending wave bandgaps and bandgaps in the acoustic domain in overlapping and audible frequency ranges. This effect is preserved also when taking the physical coupling between the two...... domains into account. Additionally, the coupling is shown to introduce extra gaps in the band structure due to modal interaction and the appearance of a cut-on frequency for the fundamental acoustic mode....

Energy Globe 2004 - Plastic bottles for a human life; Plastikflaschen fuer ein Menschenleben

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-07-01

This short article takes a look at how the Swiss Aquatic Research Centre EAWAG won a special prize for its simple method of providing people suffering from lack of clean drinking water in the aftermath of the tsunami catastrophe in south-east Asia. The method involves filling PET-bottles with water and placing them for a period of six hours in the sun, preferably on hot corrugated iron. In this way, contaminated water can be made potable.

Synthesis, structure and photoluminescence properties of amine-templated open-framework bismuth sulfates

International Nuclear Information System (INIS)

Marri, Subba R.; Behera, J.N.

2014-01-01

Two organically-templated bismuth sulfates of the compositions, [C 6 N 2 H 14 ] [Bi(SO 4 ) 2 (NO 3 )], (1) and [C 4 N 2 H 12 ] 4 [Bi 4 (SO 4 ) 10 (H 2 O) 4 ], (2), with open architecture have been synthesized and their structures determined by single crystal X-ray diffraction. 1 has a corrugated layered structure with 8-membered aperture wherein the SO 4 tetrahedra and the BiO 8 polyhedra join together to form (4, 4) net sheets of the metal centers while 2 has a three-dimensional structure possessing 8- and 12-membered channels. Both the compounds show good fluorescence properties exhibiting blue luminescence. Time-resolved fluorescence behavior of 1 and 2 shows mean fluorescence life time of 0.9 and 1.0 ns, respectively. - Graphical abstract: Two open-framework bismuth sulfates with the layered and three-dimensional structures have been synthesized and characterized. Both the compounds show good fluorescence properties exhibiting blue luminescence. Display Omitted - Highlights: • Two organically-templated bismuth sulfates with open architecture have been synthesized and characterized. • One has a corrugated layered structure while the other one has a three-dimensional structure possessing channels. • They are novel in that open-framework three-dimensional main group metal sulfates are first to be reported. • They show good fluorescence properties exhibiting blue luminescence

Mixed waste paper as a fuel

International Nuclear Information System (INIS)

Kersletter, J.D.; Lyons, J.K.

1991-01-01

A successful recycling program requires several components: education and promotion, convenient collection service, and most importantly, a market for collected materials. In Washington state, domestic markets currently have, or are building, the capacity to use most of the glass, newsprint, aluminum, tin cans, and corrugated materials that are collected. Unfortunately, markets for mixed waste paper (MWP), a major component of the state's solid waste stream, have been slow to develop and are unable to absorb the tremendous volumes of material generated. The American Paper Stock Institute classifies MWP as low grade paper such as magazines, books, scrap paper, non-corrugated cardboard (boxboard/chipboard), and construction paper. When viewed as part of a curbside collection program MWP consists primarily of catalogs, binder paper, magazines, brochures, junk mail, cereal boxes, and other household packaging items. A comprehensive analysis of Washington State's solid waste stream showed that during 1988, Washington citizens generated approximately 460,000 tons of mixed waste paper. No small amount, this is equivalent to more than 10% of the total solid waste generated in the state, and is expected to increase. Current projections of MWP generation rates indicated that Washington citizens could discard as much as 960,000 tons of MWP by the year 2010 making it one of the single largest components of the state's solid waste stream. This paper reports on the use of MWP as fuel source

Neuroticism modifies psychophysiological responses to fearful films.

Directory of Open Access Journals (Sweden)

Emmanuelle Reynaud

Full Text Available BACKGROUND: Neuroticism is a personality component frequently found in anxious and depressive psychiatric disorders. The influence of neuroticism on negative emotions could be due to its action on stimuli related to fear and sadness, but this remains debated. Our goal was thus to better understand the impact of neuroticism through verbal and physiological assessment in response to stimuli inducing fear and sadness as compared to another negative emotion (disgust. METHODS: Fifteen low neurotic and 18 high neurotic subjects were assessed on an emotional attending task by using film excerpts inducing fear, disgust, and sadness. We recorded skin conductance response (SCR and corrugator muscle activity (frowning as indices of emotional expression. RESULTS: SCR was larger in high neurotic subjects than in low neurotics for fear relative to sadness and disgust. Moreover, corrugator activity and SCR were larger in high than in low neurotic subjects when fear was induced. CONCLUSION: After decades of evidence that individuals higher in neuroticism experience more intense emotional reactions to even minor stressors, our results indicate that they show greater SCR and expressive reactivity specifically to stimuli evoking fear rather than to those inducing sadness or disgust. Fear processing seems mainly under the influence of neuroticism. This modulation of autonomic activity by neurotics in response to threat/fear may explain their increased vulnerability to anxious psychopathologies such as PTSD (post traumatic stress disorder.

Structure formation in bis(terpyridine) derivative adlayers: molecule-substrate versus molecule-molecule interactions.

Science.gov (United States)

Hoster, Harry E; Roos, Matthias; Breitruck, Achim; Meier, Christoph; Tonigold, Katrin; Waldmann, Thomas; Ziener, Ulrich; Landfester, Katharina; Behm, R Jürgen

2007-11-06

The influence of the substrate and the deposition conditions-vapor deposition versus deposition from solution-on the structures formed upon self-assembly of deposited bis(terpyridine) derivative (2,4'-BTP) monolayers on different hexagonal substrates, including highly oriented pyrolytic graphite (HOPG), Au(111), and (111)-oriented Ag thin films, was investigated by high-resolution scanning tunneling microscopy and by model calculations of the intermolecular energies and the lateral corrugation of the substrate-adsorbate interaction. Similar quasi-quadratic network structures with almost the same lattice constants obtained on all substrates are essentially identical to the optimum configuration expected from an optimization of the adlayer structure with C-H...N-type bridging bonds as a structure-determining factor, which underlines a key role of the intermolecular interactions in adlayer order. Slight distortions from the optimum values to form commensurate adlayer structures on the metal substrates and the preferential orientation of the adlayer with respect to the substrate are attributed to the substrate-adsorbate interactions, specifically, the lateral corrugation in the substrate-adsorbate interaction upon lateral displacement and rotation of the adsorbed BTP molecules. The fact that similar adlayer structures are obtained on HOPG under ultrahigh vacuum conditions (solid|gas interface) and on HOPG in trichlorobenzene (solid|liquid interface) indicates that the intermolecular interactions are not severely affected by the solvent.

Quantifying the Hierarchical Order in Self-Aligned Carbon Nanotubes from Atomic to Micrometer Scale.

Science.gov (United States)

Meshot, Eric R; Zwissler, Darwin W; Bui, Ngoc; Kuykendall, Tevye R; Wang, Cheng; Hexemer, Alexander; Wu, Kuang Jen J; Fornasiero, Francesco

2017-06-27

Fundamental understanding of structure-property relationships in hierarchically organized nanostructures is crucial for the development of new functionality, yet quantifying structure across multiple length scales is challenging. In this work, we used nondestructive X-ray scattering to quantitatively map the multiscale structure of hierarchically self-organized carbon nanotube (CNT) "forests" across 4 orders of magnitude in length scale, from 2.0 Å to 1.5 μm. Fully resolved structural features include the graphitic honeycomb lattice and interlayer walls (atomic), CNT diameter (nano), as well as the greater CNT ensemble (meso) and large corrugations (micro). Correlating orientational order across hierarchical levels revealed a cascading decrease as we probed finer structural feature sizes with enhanced sensitivity to small-scale disorder. Furthermore, we established qualitative relationships for single-, few-, and multiwall CNT forest characteristics, showing that multiscale orientational order is directly correlated with number density spanning 10 9 -10 12 cm -2 , yet order is inversely proportional to CNT diameter, number of walls, and atomic defects. Lastly, we captured and quantified ultralow-q meridional scattering features and built a phenomenological model of the large-scale CNT forest morphology, which predicted and confirmed that these features arise due to microscale corrugations along the vertical forest direction. Providing detailed structural information at multiple length scales is important for design and synthesis of CNT materials as well as other hierarchically organized nanostructures.

Displacive phase transition at the 5/3 monolayer of Pb on Ge(001)

Science.gov (United States)

Cvetko, D.; Ratto, F.; Cossaro, A.; Bavdek, G.; Morgante, A.; Floreano, L.

2005-07-01

At a coverage of 5/3 monolayer (ML), Pb adsorbed on Ge(001) forms a ground phase displaying a ((21)/(06)) symmetry. This phase undergoes two reversible phase transitions ((21)/(06))↔((21)/(03))↔(2×1) at the critical temperatures Tc1˜178K and Tc2˜375K , respectively. We investigated the behavior of the relevant order parameters at the critical temperatures by means of He and in-plane x-ray diffraction (HAS and XRD, respectively). Both phase transitions at the critical temperature put in evidence a clear order-disorder behavior, in agreement with the universality class expected for the corresponding symmetry group transformation. The low-temperature transition yields the critical exponent of the two-dimensional (2-D) Ising universality class, whereas the three-state Potts’ critical exponents are found for the high-temperature transition. By out-of-plane XRD measurements, the low-temperature phase transition is observed to be accompanied by a static surface distortion at room temperature. A complementary HAS study of the temperature evolution of the surface charge corrugation reveals that the complete ((21)/(06))↔((21)/(03)) transition is of the displacive type. On the contrary, the high-temperature phase transition does not show any change of the surface corrugation up to its irreversible decomposition, thus pointing to a pure order-disorder character.

Using memory-efficient algorithm for large-scale time-domain modeling of surface plasmon polaritons propagation in organic light emitting diodes

Science.gov (United States)

Zakirov, Andrey; Belousov, Sergei; Valuev, Ilya; Levchenko, Vadim; Perepelkina, Anastasia; Zempo, Yasunari

2017-10-01

We demonstrate an efficient approach to numerical modeling of optical properties of large-scale structures with typical dimensions much greater than the wavelength of light. For this purpose, we use the finite-difference time-domain (FDTD) method enhanced with a memory efficient Locally Recursive non-Locally Asynchronous (LRnLA) algorithm called DiamondTorre and implemented for General Purpose Graphical Processing Units (GPGPU) architecture. We apply our approach to simulation of optical properties of organic light emitting diodes (OLEDs), which is an essential step in the process of designing OLEDs with improved efficiency. Specifically, we consider a problem of excitation and propagation of surface plasmon polaritons (SPPs) in a typical OLED, which is a challenging task given that SPP decay length can be about two orders of magnitude greater than the wavelength of excitation. We show that with our approach it is possible to extend the simulated volume size sufficiently so that SPP decay dynamics is accounted for. We further consider an OLED with periodically corrugated metallic cathode and show how the SPP decay length can be greatly reduced due to scattering off the corrugation. Ultimately, we compare the performance of our algorithm to the conventional FDTD and demonstrate that our approach can efficiently be used for large-scale FDTD simulations with the use of only a single GPGPU-powered workstation, which is not practically feasible with the conventional FDTD.

Metal processing with ultrashort laser pulses

Science.gov (United States)

Banks, Paul S.; Felt, M. D.; Komashko, Aleksey M.; Perry, Michael D.; Rubenchik, Alexander M.; Stuart, Brent C.

2000-08-01

Femtosecond laser ablation has been shown to produce well-defined cuts and holes in metals with minimal heat effect to the remaining material. Ultrashort laser pulse processing shows promise as an important technique for materials processing. We will discuss the physical effects associated with processing based experimental and modeling results. Intense ultra-short laser pulse (USLP) generates high pressures and temperatures in a subsurface layer during the pulse, which can strongly modify the absorption. We carried out simulations of USLP absorption versus material and pulse parameters. The ablation rate as function of the laser parameters has been estimated. Since every laser pulse removes only a small amount of material, a practical laser processing system must have high repetition rate. We will demonstrate that planar ablation is unstable and the initially smooth crater bottom develops a corrugated pattern after many tens of shots. The corrugation growth rate, angle of incidence and the polarization of laser electric field dependence will be discussed. In the nonlinear stage, the formation of coherent structures with scales much larger than the laser wavelength was observed. Also, there appears to be a threshold fluence above which a narrow, nearly perfectly circular channel forms after a few hundred shots. Subsequent shots deepen this channel without significantly increasing its diameter. The role of light absorption in the hole walls will be discussed.

Superhard Rhenium/Tungsten Diboride Solid Solutions.

Science.gov (United States)

Lech, Andrew T; Turner, Christopher L; Lei, Jialin; Mohammadi, Reza; Tolbert, Sarah H; Kaner, Richard B

2016-11-02

Rhenium diboride (ReB 2 ), containing corrugated layers of covalently bonded boron, is a superhard metallic compound with a microhardness reaching as high as 40.5 GPa (under an applied load of 0.49 N). Tungsten diboride (WB 2 ), which takes a structural hybrid between that of ReB 2 and AlB 2 , where half of the boron layers are planar (as in AlB 2 ) and half are corrugated (as in ReB 2 ), has been shown not to be superhard. Here, we demonstrate that the ReB 2 -type structure can be maintained for solid solutions of tungsten in ReB 2 with tungsten content up to a surprisingly large limit of nearly 50 atom %. The lattice parameters for the solid solutions linearly increase along both the a- and c-axes with increasing tungsten content, as evaluated by powder X-ray and neutron diffraction. From micro- and nanoindentation hardness testing, all of the compositions within the range of 0-48 atom % W are superhard, and the bulk modulus of the 48 atom % solid solution is nearly identical to that of pure ReB 2 . These results further indicate that ReB 2 -structured compounds are superhard, as has been predicted from first-principles calculations, and may warrant further studies into additional solid solutions or ternary compounds taking this structure type.