WorldWideScience

Sample records for two-layer falling films

  1. TWO-LAYER MODEL DESCRIPTION OF POLYMER THIN FILM DYNAMICS

    Institute of Scientific and Technical Information of China (English)

    Dong-dong Peng; Ran-xing Nancy Li; Chi-hang Lam; Ophelia K.C.Tsui

    2013-01-01

    Experiments in the past two decades have shown that the glass transition temperature of polymer films can become noticeably different from that of the bulk when the film thickness is decreased below ca.100 nm.It is broadly believed that these observations are caused by a nanometer interfacial layer with dynamics faster or slower than that of the bulk.In this paper,we examine how this idea may be realized by using a two-layer model assuming a hydrodynamic coupling between the interfacial layer and the remaining,bulk-like layer in the film.Illustrative examples will be given showing how the two-layer model is applied to the viscosity measurements of polystyrene and polymethylmethacrylate films supported by silicon oxide,where divergent thickness dependences are observed.

  2. Falling Liquid Films

    CERN Document Server

    Kalliadasis, S; Scheid, B

    2012-01-01

    This research monograph gives a detailed review of the state-of-the-art theoretical methodologies for the analysis of dissipative wave dynamics and pattern formation on the surface of a film falling down a planar, inclined substrate. This prototype is an open-flow hydrodynamic instability representing an excellent paradigm for the study of complexity in active nonlinear media with energy supply, dissipation and dispersion. Whenever possible, the link between theory and experiments is illustrated and the development of order-of-magnitude estimates and scaling arguments is used to facilitate the

  3. Dynamics of turbulent falling films

    Science.gov (United States)

    O'Naraigh, Lennon; Matar, Omar

    2012-11-01

    The dynamics of laminar falling films have received considerable attention over the past several decades. In contrast, turbulent falling films have been the subject of far fewer studies. We seek to redress this balance by studying the stability of falling films which have already undergone a transition from a laminar to a turbulent flow regime. We derive a uniform-film base-state for this flow by assuming the averaged turbulent velocity field to be steady and fully-developed, and by employing a modified version of mixing-length theory. The latter features an interpolation function for the eddy viscosity, and van Driest-type functions for turbulence-damping near the wall and interface regions. The predicted base-state streamwise velocity component is in good agreement with experimental data. A linear stability analysis of this base-state is then carried out by solving a modified version of the Orr-Sommerfeld equation. Our results suggest that the unstable mode is a long-wave one. This provides motivation for the derivation of long-wave equations for the nonlinear evolution of the film.

  4. [Two-layer adhesive film Diplen-denta C--a new compound containing polymer base and active component Solcoseryl].

    Science.gov (United States)

    Abakarova, D S

    2007-01-01

    Characteristics of the main components of a new effective long-lasting dosage form--biopolymer two-layer adhesive solcoseryl containing film Diplen-denta C--are presented. It has a potent wound-healing action on oral mucosa, retains therapeutic properties during long time, is self dissolving and can be easily fixed on oral mucous membrane.

  5. A two-layer structured PbI2 thin film for efficient planar perovskite solar cells

    Science.gov (United States)

    Ying, Chao; Shi, Chengwu; Wu, Ni; Zhang, Jincheng; Wang, Mao

    2015-07-01

    In this paper, a two-layer structured PbI2 thin film was constructed by the spin-coating procedure using a 0.80 M PbI2 solution in DMF and subsequent close-spaced vacuum thermal evaporation using PbI2 powder as a source. The bottom PbI2 thin film was compact with a sheet-like appearance, parallel to the FTO substrate, and can be easily converted to a compact perovskite thin film to suppress the charge recombination of the electrons of the TiO2 conduction band and the holes of the spiro-OMeTAD valence band. The top PbI2 thin film was porous with nano-sheet arrays, perpendicular to the FTO substrate, and can be easily converted to a porous perovskite thin film to improve the hole migration from the perovskite to spiro-OMeTAD and the charge separation at the perovskite/spiro-OMeTAD interface. The planar perovskite solar cells based on the two-layer structured PbI2 thin film exhibited a photoelectric conversion efficiency of 11.64%, along with an open-circuit voltage of 0.90 V, a short-circuit photocurrent density of 19.29 mA cm-2 and a fill factor of 0.67.

  6. Functional barrier in two-layer recycled PP films for food packaging applications

    Science.gov (United States)

    Scarfato, P.; Di Maio, L.; Milana, M. R.; Feliciani, R.; Denaro, M.; Incarnato, L.

    2014-05-01

    A preliminary study on bi-layer virgin/contaminated polypropylene co-extruded films was performed in order to evaluate the possibility to realize an effective functional barrier in PP-based multi-layer systems. In particular, the specific migration in 10% v/v aqueous ethanol of two surrogate contaminants (phenyl-cyclohexane and benzophenone) contained in the contaminated layer across the PP functional barrier was measured at different times and the results were compared with those obtained from a contaminated mono-layer polypropylene film. Moreover, the thermal and mechanical performances of the produced films were investigated.

  7. Thickness Determination for a Two-Layered Composite of a Film and a Plate by Low-Frequency Ultrasound

    Institute of Scientific and Technical Information of China (English)

    MAO Jie; LI Ming-Xuan; WANG Xiao-Min

    2007-01-01

    We present an ultrasonic method for determining the thickness of a composite consisting of a soft thin film attached to a hard plate substrate, by resonance spectra in the low frequency region. The interrogating waves can be incident only to the two-layered composite from the substrate side. The reflection spectra are obtained by FFT analysis of the compressive pulsed echoes from the composite, and the thicknesses of the film and the substrate are simultaneously inversed by the simulated annealing method from the resonant frequencies knowing other acoustical parameters in prior. The sensitivity of the method to individual thickness, its convergence and stability against experimental noises are studied. Experiment with interrogating wavelength 4 times larger than the film thickness in a sample of a polymer film (0.054 mm) on an aluminium plate (6.24 mm) verifies the validity of the method. The average relative errors in the measurement of the thicknesses of the film and the substrate are found to be -4.1% and -0.62%, respectively.

  8. Interfacial Evaporation of Falling Liquid Films with Wall Heating

    Institute of Scientific and Technical Information of China (English)

    张金涛; 王补宣; 彭晓峰

    2001-01-01

    The interfacial evaporation of falling water films with wall heating was experimentally studied andanalyzed. The results presented in this paper showed that the capillary-induced interfacial evaporation playedan important role in heat transfer of a falling liquid film. It would be independent of the wall heat flux andsomewhat lower than that without wall heating for impure fluids such as water-air system. The thermodynamicanalysis conducted gave a theoretical basis for the experimental observations. The effective capillary radiuswas correlated with the mass flow rate. The experimental results and analysis showed that the interfacialevaporation should be taken into account in the study of falling liquid film heat transfer.``

  9. Controlled Release of Antimicrobial ClO2 Gas from a Two-Layer Polymeric Film System.

    Science.gov (United States)

    Bai, Zhifeng; Cristancho, Diego E; Rachford, Aaron A; Reder, Amy L; Williamson, Alexander; Grzesiak, Adam L

    2016-11-16

    We report a two-component label system comprising a chlorite-containing polymer film and an acid-containing polymer film that can release antimicrobial ClO2 gas upon adhering the two films together to enable a reaction of the chlorite and acid under moisture exposure. The chlorite-containing film comprises a commercial acrylate-based pressure-sensitive adhesive polymer impregnated with sodium chlorite. The acid-containing film comprises a commercial poly(vinyl alcohol) polymer loaded with tartaric acid. Both of the films were prepared on low ClO2-absorbing substrate films from stable aqueous systems of the polymers with high reagent loading. Rapid and sustained releases of significant amounts of ClO2 gas from the label system were observed in an in situ quantification system using UV-vis spectroscopy. It was found that the ClO2 release is slower at a lower temperature and can be accelerated by moisture in the atmosphere and the films. Controlled release of ClO2 gas from the label system was demonstrated by tailoring film composition and thickness. A model was developed to extract release kinetics and revealed good conversions of the label system. This two-component system can potentially be applied as a two-part label without premature release for applications in food packaging.

  10. Assembly of 1D nanofibers into a 2D bi-layered composite nanofibrous film with different functionalities at the two layers via layer-by-layer electrospinning.

    Science.gov (United States)

    Wang, Zijiao; Ma, Qianli; Dong, Xiangting; Li, Dan; Xi, Xue; Yu, Wensheng; Wang, Jinxian; Liu, Guixia

    2016-12-21

    A two-dimensional (2D) bi-layered composite nanofibrous film assembled by one-dimensional (1D) nanofibers with trifunctionality of electrical conduction, magnetism and photoluminescence has been successfully fabricated by layer-by-layer electrospinning. The composite film consists of a polyaniline (PANI)/Fe3O4 nanoparticle (NP)/polyacrylonitrile (PAN) tuned electrical-magnetic bifunctional layer on one side and a Tb(TTA)3(TPPO)2/polyvinylpyrrolidone (PVP) photoluminescent layer on the other side, and the two layers are tightly combined face-to-face together into the novel bi-layered composite film of trifunctionality. The brand-new film has totally different characteristics at the double layers. The electrical conductivity and magnetism of the electrical-magnetic bifunctional layer can be, respectively, tunable via modulating the PANI and Fe3O4 NP contents, and the highest electrical conductivity can reach up to the order of 10(-2) S cm(-1), and predominant intense green emission at 545 nm is obviously observed in the photoluminescent layer under the excitation of 357 nm single-wavelength ultraviolet light. More importantly, the luminescence intensity of the photoluminescent layer remains almost unaffected by the electrical-magnetic bifunctional layer because the photoluminescent materials have been successfully isolated from dark-colored PANI and Fe3O4 NPs. By comparing with the counterpart single-layered composite nanofibrous film, it is found that the bi-layered composite nanofibrous film has better performance. The novel bi-layered composite nanofibrous film with trifunctionality has potential in the fields of nanodevices, molecular electronics and biomedicine. Furthermore, the design conception and fabrication technique for the bi-layered multifunctional film provide a new and facile strategy towards other films of multifunctionality.

  11. Falling liquid films with blowing and suction

    CERN Document Server

    Thompson, Alice B; Papageorgiou, Demetrios T

    2015-01-01

    Flow of a thin viscous film down a flat inclined plane becomes unstable to long wave interfacial fluctuations when the Reynolds number based on the mean film thickness becomes larger than a critical value (this value decreases as the angle of inclination with the horizontal increases, and in particular becomes zero when the plate is vertical). Control of these interfacial instabilities is relevant to a wide range of industrial applications including coating processes and heat or mass transfer systems. This study considers the effect of blowing and suction through the substrate in order to construct from first principles physically realistic models that can be used for detailed passive and active control studies of direct relevance to possible experiments. Two different long-wave, thin-film equations are derived to describe this system; these include the imposed blowing/suction as well as inertia, surface tension, gravity and viscosity. The case of spatially periodic blowing and suction is considered in detail...

  12. Secondary instabilities of linearly heated falling films

    Institute of Scientific and Technical Information of China (English)

    HU Jun; SUN Dejun; HU Guohui; YIN Xieyuan

    2005-01-01

    Secondary instabilities of linearly heated failing films are studied through three steps. Firstly, the analysis of the primary linear instability on Miladinova's long wave equation of the linearly heated film is performed. Secondly, the similar Landau equation is derived through weak nonlinear theory, and a two-dimensional nonlinear saturation solution of primary instability is obtained within the weak nonlinear domain. Thirdly, the secondary (three-dimensional) instability of the two-dimensional wave is studied by the Floquet theorem.Our secondary instability analysis shows that the Marangoni number has destabilization effect on the secondary instability.

  13. Flow Visualization and Pattern Formation in Vertically Falling Liquid Films

    Science.gov (United States)

    Balakotaiah, Vemuri; Malamataris, Nikolaos

    2008-11-01

    Analytical results of a low-dimensional two equation h-q model and results of a direct numerical simulation of the transient two-dimensional Navier Stokes equations are presented for vertically falling liquid films along a solid wall. The numerical study aims at the elucidation of the hydrodynamics of the falling film. The analytical study aims at the calculation of the parameter space where pattern formation occurs for this flow. It has been found that when the wave amplitude exceeds a certain magnitude, flow reversal occurs in the film underneath the minimum of the waves [1]. The instantaneous vortical structures possess two hyperbolic points on the vertical wall and an elliptic point in the film. As the wave amplitude increases further, the elliptic point reaches the free surface of the film and two more hyperbolic points are formed in the free surface that replace the elliptic point. Between the two hyperbolic points on the free surface, the streamwise component of velocity is negative and the film is divided into asymmetric patterns of up and down flows. Depending on the value of the Kapitza number, these patterns are either stationary or oscillatory. Physical reasons for the influence of the Kapitza number on pattern formation are given. Movies are shown where the pattern formation is demonstrated. [1] N.A.Malamataris and V.Balakotaiah (2008), AIChE J., 54(7), p. 1725-1740

  14. AGU Cinema: Festival of short science films at Fall Meeting

    Science.gov (United States)

    Harned, Douglas A.

    2012-11-01

    New technologies have revolutionized the use of video as a means of science communication and have made it easier to create, distribute, and view. With video having become omnipresent in our culture, it sometime supplements or even replaces writing in many science and education applications. An inaugural science film festival sponsored by AGU at the 2012 Fall Meeting in San Francisco, Calif., in December will showcase short videos—30 minutes or less in length—developed to disseminate scientific results to various audiences and to enhance learning in the classroom. AGU Cinema will feature professionally produced, big budget films alongside low-budget videos aimed at niche audiences and made by amateurs. The latter category includes videos made by governmental agency scientists, educators, communications specialists within scientific organizations, and Fall Meeting oral and poster presenters.

  15. Viscous falling film instability around a vertical moving cylinder

    Institute of Scientific and Technical Information of China (English)

    Kadry Zakaria; Yasser Gamiel

    2012-01-01

    The present work discusses both the linear and nonlinear stability conditions of a viscous falling film down the outer surface of a solid vertical cylinder which moves in the direction of its axis with a constant velocity.After studying the linear conditions,a generalized nonlinear kinematic model is then derived to present the physical system.Applying the boundary conditions,analytical solutions are obtained using the long-wave perturbation method.In the first step,the normal mode method is used to characterize the linear behaviors.In the second step,the nonlinear film flow model is solved by using the method of multiple scales,to obtain Ginzburg-Landau equation.The influence of some physical parameters is discussed in both linear and nonlinear steps of the problem,and the results are displayed in many plots showing the stability criteria in various parameter planes.

  16. Three-dimensional wave evolution on electrified falling films

    CERN Document Server

    Tomlin, R J; Pavliotis, G A

    2016-01-01

    We consider the full 3D dynamics of a thin falling liquid film on a flat plate inclined at some non-zero angle to the horizontal. In addition to gravitational effects, the flow is driven by an electric field, which is normal to the substrate far from the flow. We study both the cases of overlying and hanging films, where the liquid rests above and below the substrate respectively. Starting with the Navier-Stokes equations coupled with electrostatics, a fully nonlinear 2D Benney equation for the interfacial dynamics is derived valid for waves that are long compared to the film thickness. The weakly nonlinear evolution is governed by a Kuramoto-Sivashinsky equation with a non-local term due to the electric field effect. The electric field term is linearly destabilising and produces growth rates proportional to the cube of the size of the wavenumber vector of the perturbations. It is found that transverse gravitational instabilities are always present for hanging films and lead to unboundedness of solutions even...

  17. Progress in Polyimide Films for Two-Layer Type Flexible Copper Clad Laminate%二层型挠性覆铜板用聚酰亚胺的研究进展

    Institute of Scientific and Technical Information of China (English)

    刁恩晓; 李帆; 舒适; 肖炳瑞; 黄永发; 王平; 刘峰

    2015-01-01

    The fast development of electronic industry puts forward higher requirements for the property of flexible copper clad laminate (FCCL). The research progress of two-layer type FCCL, which using polyimide film as substract, was reviewed from improving the adhesive property, dielectric property and heat resistance, and the research directions of two-layer type FCCL were proposed.%电子行业的快速发展对二层型挠性覆铜板的性能提出了更高的要求,针对以聚酰亚胺薄膜为基底材料的二层型挠性覆铜板,分别从改善粘结性能、介电性能和耐热性能3个方面综述了二层型挠性覆铜板的研究进展,并展望了二层型挠性覆铜板的研究方向。

  18. Heat and Mass Transfer in a Falling Film Evaporator with Aqueous Lithium Bromide Solution

    Science.gov (United States)

    Olbricht, M.; Addy, J.; Luke, A.

    2016-09-01

    Horizontal tube bundles are often used as falling film evaporators in absorption chillers, especially for systems working at low pressure as H2O/LiBr. Experimental investigations are carried out in a falling film evaporator consisting of a horizontal tube bundle with eighty horizontal tubes installed in an absorption chiller because of a lack of consistent data for heat and mass transfer in the literature. The heat and mass transfer mechanisms and the flow pattern in the falling film are analysed and compared with correlations from literature. The deviations of the experimental data from those of the correlations are within a tolerance of 30%. These deviations may be explained by a change of the flow pattern at a lower Reynolds number than compared to the literature.

  19. The effect of interfacial evaporation on heat and mass transfer of falling liquid film

    Institute of Scientific and Technical Information of China (English)

    WANG; Buxuan; (

    2001-01-01

    [1]Wasden, F.K., Dukler, A.E., Insight into the hydrodynamics of free falling wavy films, AIChE J., 1989, 35(2): 187.[2]Jayanti, S., Hewitt, G.F., Hydrodynamics and heat transfer of wavy thin film flow, Int. J. Heat Mass Transfer, 1997, 40(10): 179.[3]Seban, R.A., Faghri, A., Evaporation and heating with turbulent falling liquid films, ASME J. Heat Transfer, 1976, 98C: 315.[4]Yang, W.M., Evaporation cooling of liquid film in turbulent mixed convection channel flows, Int. J. Heat Mass Transfer, 1998, 41(23): 3719.[5]Wang, B.X., Zhang, J.T., Peng, X.F., Experimental study on the dryout heat flux of falling liquid film, accepted by Int. J. Heat Mass Transfer as HMT# 2507.[6]Udell, K.S., Heat transfer in porous media heated from above with evaporation, condensation, and capillary effects, ASME J. Heat Transfer, 1983, 105: 485.[7]Carey, V.P., Liquid-Vapor Phase-Change Phenomena——An Introduction to the Thermophysics of Vaporization and Conduction Processes in Heat Transfer Equipment, Washington: Hemisphere Publishing Corporation, 1992, 112.[8]Eames, I.W., Marr, N.J., Sabir, H., The evaporation coefficient of water: a review, Int. J. Heat Mass Transfer, 1997, 40(12): 2963.[9]Israelachvili, J.N., Intermolecular and Surface Forces, San Diego: Academic Press, 1990, 16-30.[10]Holman, J.P., Heat Transfer, 5th ed., Tokyo: McGraw-Hill, Inc, 1981.[11]Zhang, J.T., Wang, B.X., Peng, X.F., Falling liquid film thickness measurement by optical-electronic method, Rev. Scientific Instruments, 2000, 71(4): [12]Zhang, J.T., Wang, B.X., Peng, X.F., Investigation on the interfacial evaporation of falling liquid film with wall heating, accepted by J. Tsinghua University.[13]Fujita, T., Ueda, T., Heat transfer to falling liquid films and film breakdown, Int. J. Heat Mass Transfer, 1978, 21: 97.[14]Bohn, M.S., Davis, S.H., Thermocapillary breakdown of falling liquid films at high Reynolds numbers, Int. J. Heat Masss Transfer, 1993, 36

  20. Evaporation of pure liquids with increased viscosity in a falling film evaporator

    Science.gov (United States)

    Weise, Felix; Scholl, Stephan

    2009-05-01

    The present study investigated fluid dynamics and heat transfer of viscous pure liquids in a falling film evaporator. This is of special benefit as it avoids mass transfer effects on the evaporation behaviour. Experiments at a single-tube glass falling film evaporator were conducted. It allowed a full-length optical film observation with a high-speed camera. Additionally the evaporator was equipped with a slotted weir distribution device. Test fluids provided viscosities ranging from μ = 0.3 to 41 mPa s. The Reynolds number was between 0.7 and 1,930. Surface evaporation and the transition to nucleate boiling were studied to gain information about the film stability at maximum wall superheat. A reliable database for laminar and laminar-wavy viscous single component films was created. The experimental results show a significant enhancement in the wave development due to the film distribution. A wavy flow with different wave velocities was superposed to the film in each liquid load configuration without causing a film breakdown or dry spots on the evaporator tube. It was found that nucleate boiling can be allowed without causing film instabilities over a significant range of wall superheat.

  1. Evaporation of pure liquids with increased viscosity in a falling film evaporator

    Energy Technology Data Exchange (ETDEWEB)

    Weise, Felix; Scholl, Stephan [Technical University of Braunschweig (DE). Institute for Chemical and Thermal Process Engineering (ICTV)

    2009-05-15

    The present study investigated fluid dynamics and heat transfer of viscous pure liquids in a falling film evaporator. This is of special benefit as it avoids mass transfer effects on the evaporation behaviour. Experiments at a single-tube glass falling film evaporator were conducted. It allowed a full-length optical film observation with a high-speed camera. Additionally the evaporator was equipped with a slotted weir distribution device. Test fluids provided viscosities ranging from {mu}=0.3 to 41 mPa s. The Reynolds number was between 0.7 and 1,930. Surface evaporation and the transition to nucleate boiling were studied to gain information about the film stability at maximum wall superheat. A reliable database for laminar and laminar-wavy viscous single component films was created. The experimental results show a significant enhancement in the wave development due to the film distribution. A wavy flow with different wave velocities was superposed to the film in each liquid load configuration without causing a film breakdown or dry spots on the evaporator tube. It was found that nucleate boiling can be allowed without causing film instabilities over a significant range of wall superheat. (orig.)

  2. New experimental technique for the measurement of the velocity field in thin films falling over obstacles

    Science.gov (United States)

    Landel, Julien R.; Daglis, Ana; McEvoy, Harry; Dalziel, Stuart B.

    2014-11-01

    We present a new experimental technique to measure the surface velocity of a thin falling film. Thin falling films are important in various processes such as cooling in heat exchangers or cleaning processes. For instance, in a household dishwasher cleaning depends on the ability of a thin draining film to remove material from a substrate. We are interested in the impact of obstacles attached to a substrate on the velocity field of a thin film flowing over them. Measuring the velocity field of thin falling films is a challenging experimental problem due to the small depth of the flow and the large velocity gradient across its depth. We propose a new technique based on PIV to measure the plane components of the velocity at the surface of the film over an arbitrarily large area and an arbitrarily large resolution, depending mostly on the image acquisition technique. We perform experiments with thin films of water flowing on a flat inclined surface, made of glass or stainless steel. The typical Reynolds number of the film is of the order of 100 to 1000, computed using the surface velocity, the film thickness and the kinematic viscosity of the film. We measure the modification to the flow field, from a viscous-gravity regime, caused by small solid obstacles, such as three-dimensional hemispherical obstacles and two-dimensional steps. We compare our results with past theoretical and numerical studies. This material is based upon work supported by the Defense Threat Reduction Agency under Contract No. HDTRA1-12-D-0003-0001.

  3. Mathematical simulation of lithium bromide solution laminar falling film evaporation in vertical tube

    Science.gov (United States)

    Shi, Chengming; Wang, Yang; Hu, Huili; Yang, Ying

    2010-06-01

    For utilization of the residual heat of flue gas to drive the absorption chillers, a lithium-bromide falling film in vertical tube type generator is presented. A mathematical model was developed to simulate the heat and mass coupled problem of laminar falling film evaporation in vertical tube. In the model, the factor of mass transfer was taken into account in heat transfer performance calculation. The temperature and concentration fields were calculated. Some tests were conducted for the factors such as Re number, heating flux, the inlet concentration and operating pressure which can affect the heat and mass transfer performance in laminar falling film evaporation. The heat transfer performance is enhanced with the increasing of heat flux. An increasing inlet concentration can weaken the heat transfer performance. The operating pressure hardly affects on heat and mass transfer. The bigger inlet Re number means weaker heat transfer effects and stronger mass transfer. The mass transfer obviously restrains the heat transfer in the falling film solution. The relation between dimensionless heat transfer coefficient and the inlet Re number is obtained.

  4. Aspects of sorption processes in thermosiphon and in falling film arrangements

    Energy Technology Data Exchange (ETDEWEB)

    Kockum, Henrik

    1998-09-01

    A study concerning closure relations pertinent to the design of sorption equipment of absorption heat pumps has been undertaken. Specifically, thermosiphon and vertical falling film arrangements were studied. For the thermosiphon, experimental data on the void fraction, the friction and orifice pressure drops, and the heat transfer coefficient at sub-atmospheric pressures were obtained for vaporizing water and vaporizing water-sugar mixtures. Empirical correlations were produced for all quantities. Furthermore, a semi-theoretical model for the void fraction was derived; this model compared favourably to existing correlations. Sample thermosiphon correlations using a two-field two-phase flow model, including a heating condensate film, were performed. For the falling film, a penetration-type of turbulence model was developed. Experimental data found in the open literature were used in the derivation. Absorption calculations then indicated that the model is appropriate for wavy-laminar flows, but not for turbulent flows. Falling film calculation results compared favourably to existing film thickness and heat transfer correlations 121 refs, 28 figs, 14 tabs

  5. Experimental and numerical analysis for optimal design parameters of a falling film evaporator

    Indian Academy of Sciences (India)

    RAJNEESH KAUSHAL; RAJ KUMAR; GAURAV VATS

    2016-06-01

    Present study exhibits an experimental examination of mass transfer coefficient and evaporative effectiveness of a falling film evaporator. Further, a statistical replica is extended in order to have optimal controlling parameters viz. non-dimensional enthalpy potential, film Reynolds number of cooling water, Reynolds number of air and relative humidity of up-streaming air. The models not only give an optimal solution but also help in establishing a correlation among controlling parameters. In this context, response surface methodology is employed by aid of design of experiment approach. Later, the response surface curves are studied using ANOVA. Finally, the relations established are confirmed experimentally to validate the models. The relations thus established are beneficent in furtherance of designing evaporators. Additionally, the presentstudy is among the first attempts to reveal the effect of humidity on the performance of falling film evaporator.

  6. Study on heat transfer for falling liquid film flow with consideration of interfacial evaporation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The interfacial evaporative heat transfer was included in the semi-empirical study of the heat transfer for the falling liquid film flow. The investigations showed that, the inclusion of the interfacial evaporative heat transfer in the turbulent model would lower the predicted convective heat transfer coefficient. Predictions of the new model resulted in a prominent deviation from that predictions of the normal model in the case of large mass flow rate and low wall heat flux. This deviation will be decreased with increasing wall heat flux, such that it will be asymptotic zero at very high wall heat flux. Predictions of the new model agreed well with the current experimental measurements. This study has verified that the Reynolds number is not the sole crucial parameter for heat transfer of falling liquid film flow, and wall heat flux will be another important independent parameter. This result is consistent with our previous studies.

  7. CFD and Experimental Analysis of a Falling Film outside Smooth and Helically Grooved Tubes

    Directory of Open Access Journals (Sweden)

    Cenk Onan

    2014-08-01

    Full Text Available Simultaneous heat and mass transfer are investigated in a falling film outside grooved and smooth tubes. A numerical analysis of the helically trapezoidal-grooved and reference smooth tube was performed in the computational fluid dynamics program “Ansys Fluent 14.” The three-dimensional model drawings in the x, y, and z coordinates are used, and the effects of the falling film outside the helically grooved tube on the surface temperature and surface heat transfer coefficient are determined. The average surface temperature, heat transfer coefficient, and Nu values are determined experimentally for a constant heat flux. An uncertainty analysis and Nu correlation for the grooved tube are also provided in this study. The Reynolds number varied between 50 and 350 for the falling film and between 1500 and 3500 for air. Using a computational fluid dynamics (CFD analysis for the reference smooth tube, the experimental results are validated within 2–12% difference. The experimental results are also within 6–13% of the grooved tubes.

  8. Natural Convection Heat and Mass Transfer from Falling Films in Vertical Channels

    Science.gov (United States)

    Buck, Gregory Allen

    1990-01-01

    In the design of solar collector/regenerators for use in open cycle absorption refrigeration (OCAR) units, the problem of predicting evaporation rates and solution temperatures is of paramount importance in determining overall cycle performance. This transport of heat and mass is dominated by natural convection with buoyant forces primarily generated as a result of film heating by the solar flux, but aided by the evaporation of water (the lighter species) into the rising moist air stream. In order to better understand the mechanism of these combined buoyant interactions, the governing equations for natural convection flow in a vertical channel bounded by a heated falling film (simulating a glazed collector/regenerator) were solved using several different finite difference techniques. The numerical results were validated against existing experimental and numerical results for simplified boundary conditions. The appropriate nondimensionalization for the falling film boundary condition was established, ostensibly for the first time, and a parametric study for an air-water vapor mixture has been presented. Curve fits to the numerical results were determined for engineering design applications. To further confirm the validity of the numerical solutions, an experimental apparatus was constructed using electric resistance heat to simulate the constant heat flux of the solar source. Water was introduced at the top of this heated vertical surface at various flow rates and under various supplied heat fluxes, and a natural convection channel flow generated between the heated falling film and a parallel, plexiglass surface. Film temperatures and moist air velocity profiles were measured at various streamwise (vertical) locations for comparison with the numerical results. In general, measured film temperatures were 15 to 20 percent lower than the predicted values, but came to within 3 percent of the predictions when experimental uncertainty was incorporated into the numerical

  9. Gas Absorption by Wavy Falling Liquid Film Formed on Inner Surface of Vertical Tubes

    Institute of Scientific and Technical Information of China (English)

    Akio Miyara; Tomoki Yamamoto; Toru Iemura; Takashi Shimada

    2003-01-01

    An experimental study on gas absorption into falling liquid film formed on inner surface of vertical tubes has been carried out in order to clarify fundamental characteristics of the gas absorption and enhancement by surface waves. The water supplied into the test tubes is periodically disturbed by fluctuating a silicon tube before the test section with a speaker and the wavy films absorb the oxygen filled in the tubes. Imposing the periodic disturbance enhances the gas absorption and the enhancement has a maximum at around 20~30 Hz, where the gas absorption is 20~30% higher. Mass transfer coefficients obtained with five tubes agree well with those obtained with single tube. Two-dimensional numerical simulations have also been conducted for gas absorption by wavy film and the enhancement mechanism of the gas absorption is discussed.

  10. Effectiveness of non-volatile falling film absorbers with solution and coolant in counter-flow

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D.S. [Austrian Institute of Technology, Dept. Energy, Giefinggasse 2, 1210 Vienna (Austria); Infante Ferreira, C.A. [Delft University of Technology, Engineering Thermodynamics, Leeghwaterstraat 44, 2628 CA Delft (Netherlands)

    2010-01-15

    Effectiveness equations are developed for non-volatile falling film absorbers with solution and coolant in counter-flow. It is shown how mixture thermodynamics and film theory can be used to simplify the problem to give eigenvalue solutions for temperature and concentration profiles and how heat and mass transfer effectiveness equations can be derived from such solutions. The results indicate that the transfer process in an absorber is driven by two driving forces, i.e. the difference between bulk solution and cooling water temperatures and the initial deviation of bulk solution from its equilibrium state. Asymptotic effectiveness equations are derived for a few limiting cases to show that they approach their counterparts in single-phase heat transfer and isothermal absorption processes. (author)

  11. The effect of interfacial evaporation on heat and mass transfer of falling liquid film

    Institute of Scientific and Technical Information of China (English)

    王补宣; 张金涛; 彭晓峰

    2001-01-01

    Analysis of experimental data and estimation of the order of magnitude for interfacial mass diffusion have demonstrated that considerable excess evaporation exists on the free interface of falling liquid film, and that the capillary pressure caused by surface tension is the driving force of this excess interfacial evaporation, which we called the “capillarity-induced interfacial evaporation”. By correlating the experimental data, an empirical expression of the effective capillary radius, r\\-e, is obtained with which the evaporative rate formula we derived and reported previously has been modified to improve the prediction of the critical heat flux for film breakdown. Comparisons with the available predicting models show that our modified equation can predict the experimental results with much lower relative deviation.

  12. Detailed hydrodynamic characterization of harmonically excited falling-film flows: A combined experimental and computational study

    Science.gov (United States)

    Charogiannis, Alexandros; Denner, Fabian; van Wachem, Berend G. M.; Kalliadasis, Serafim; Markides, Christos N.

    2017-01-01

    We present results from the simultaneous application of planar laser-induced fluorescence (PLIF), particle image velocimetry (PIV) and particle tracking velocimetry (PTV), complemented by direct numerical simulations, aimed at the detailed hydrodynamic characterization of harmonically excited liquid-film flows falling under the action of gravity. The experimental campaign comprises four different aqueous-glycerol solutions corresponding to four Kapitza numbers (Ka=14 , 85, 350, 1800), spanning the Reynolds number range Re=2.3 -320 , and with forcing frequencies fw=7 and 10 Hz . PLIF was employed to generate spatiotemporally resolved film-height measurements, and PIV and PTV to generate two-dimensional velocity-vector maps of the flow field underneath the wavy film interface. The latter allows for instantaneous, highly localized velocity-profile, bulk-velocity, and flow-rate data to be retrieved, based on which the effect of local film topology on the flow field underneath the waves is studied in detail. Temporal sequences of instantaneous and local film height and bulk velocity are generated and combined into bulk flow-rate time series. The time-mean flow rates are then decomposed into steady and unsteady components, the former represented by the product of the mean film height and mean bulk velocity and the latter by the covariance of the film-height and bulk-velocity fluctuations. The steady terms are found to vary linearly with the flow Re, with the best-fit gradients approximated closely by the kinematic viscosities of the three examined liquids. The unsteady terms, typically amounting to 5 %-10 % of the mean and peaking at approximately 20 % , are found to scale linearly with the film-height variance. And, interestingly, the instantaneous flow rate is found to vary linearly with the instantaneous film height. Both experimental and numerical flow-rate data are closely approximated by a simple analytical relationship with only minor deviations. This relationship

  13. Heat transfer for falling film evaporation of industrially relevant fluids up to very high Prandtl numbers

    Science.gov (United States)

    Gourdon, Mathias; Karlsson, Erik; Innings, Fredrik; Jongsma, Alfred; Vamling, Lennart

    2016-02-01

    In many industrial applications, falling film evaporation is an attractive technique for solvent removal due to high heat transfer and low residence times. Examples are the powder production in the dairy industry and in kraft pulp production process to remove water from so called black liquor. Common for both applications is that the fluids exhibit high viscosities in industrial practice. In this paper, results from experimental studies on both black liquor and a dairy product are reported for Prandtl numbers up to 800. The results are compared with several existing correlation in literature, and the need for a modified correlation is recognized especially to cover higher Prandtl-numbers. The following correlation for the turbulent flow region with 3 literature data from one additional study on two other fluids (propylene glycol and cyclohexanol) with fairly high Prandtl-numbers, from 40 to 58 and from 45 to 155 respectively and the agreement was within ±40 %.

  14. Separation and PurificationHomologous Compounds byof Dodecanedioic Acid from Its Falling Film Crystallization

    Institute of Scientific and Technical Information of China (English)

    李裕; 刘有智; 齐雪琴

    2004-01-01

    Separation and purification of dodecanedioic acid (DDDA) from its homologous compounds were studied experimentally by falling film crystallization (FFC). The influences of various operation parameters, including crystallizing time, flow rate of melt and temperature of glycerine bath, on purity of DDDA and crystallizing rate were investigated. Over 99% (by mole) DDDA was obtained for a feed composition of 96% (by mole). The main factors affecting the separation efficiency are flow rate of melt and temperature of glycerine bath. The crystallizing layer of DDDA was further purified by sweating and blasting. A set of optimized operation data are provided for better understanding the mechanism of heat and mass transfer in FFC, and for further industrial application of DDDA purification process.

  15. Parallelised direct numerical simulation of three-dimensional wavy falling films

    Science.gov (United States)

    Juric, Damir; Chergui, Jalel; Kahouadji, Lyes; Matar, Omar; Shin, Seungwon

    2015-11-01

    We present a computational study of falling liquid films in a three-dimensional inclined rectangular domain using the new massively parallel code, BLUE. Calculations are carried out in order to obtain several wave patterns such as occasional solitary waves, which travel downstream at a constant velocity, or less coherent structures. BLUE uses parallelization algorithms based on MPI and algebraic domain decomposition. The velocity field is solved by a parallel GMRES method for the viscous terms and the pressure by a parallel multigrid method. The method for the treatment of the fluid interfaces and capillary forces uses a parallelized Front Tracking/Level Set technique which defines the interface both by a discontinuous density field as well as by a local triangular Lagrangian mesh. This structure allows the interface to undergo large deformations including the rupture and/or coalescence of fluid interfaces. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

  16. 降膜蒸发器的研究进展%Research Progress of Falling-film Evaporator

    Institute of Scientific and Technical Information of China (English)

    张猛; 周帼彦; 朱冬生

    2012-01-01

    A review of the prior research on falling film evaporator is presented, which is widely used in all field of modem industry. Optimal design and efficient application energy are of significance for saving and environment protection. This paper looks back on fundamental principles of falling film evaporators including flow characteristics, heat transfer performance, and the effects of parameters which provide some help for design and manufacture of falling film evaporators, and introduces Enhance Technology of Twisted Tube into the application of falling film evaporator. Finally, some suggestions for further research is described.%降膜蒸发器广泛应用在现代工业的各个领域,其优化设计和高效应用对于节能和环保具有重要意义.本文分析了降膜蒸发器基本原理及特点,综述了国内外降膜蒸发器流动与传热特性、布膜及强化传热的研究情况,在此基础上,将扭曲扁管强化传热技术引入降膜蒸发器,并对降膜蒸发器的进一步研究指出方向.

  17. THE PHOTOCATALYTIC OXIDATION OF LOW CONCENTRATION MTBE ON TITANIUM DIOXIDE FROM GROUNDWATER IN A FALLING FILM REACTOR

    Science.gov (United States)

    This study focuses on three objectives: 1) to determine the feasibility of using a falling-film slurry photocatalytic reactor for the degradation of MTBE in water, 2) to assess the feasibility of MTBE photo-oxidation on TiO2 at low initial MTBE concentrations (<10 mg/L), and 3) t...

  18. Two-Layer Quantum Key Distribution

    CERN Document Server

    Ramos, Rubens Viana

    2012-01-01

    Recently a new quantum key distribution protocol using coherent and thermal states was proposed. In this work this kind of two-layer QKD protocol is formalized and its security against the most common attacks, including external control and Trojan horse attacks, is discussed.

  19. Asymptotic Law of the Falling Liquid Film Form in Partial Wetting

    Directory of Open Access Journals (Sweden)

    A. R. Pоlyanskii

    2015-01-01

    Full Text Available The paper considers a problem of falling the partially wetting liquid across solid surface taking into account the disjoining pressure for liquid particles in its thin layers close to the three phase contact line. Within the frame of dropping liquid hydrodynamics it is easy to take into consideration the surface tension. On the other hand, with available surface tension, the attempts to fulfill Yung condition for a contact angle encounter truly insurmountable difficulties. Generally speaking, this problem has no solution within the limits of standard hydrodynamic theory of viscous liquid if the surface tension occurs and, at the same time, it is necessary to fulfill Yung condition for partial wetting. These problems can be solved if, instead of Yung condition, which is specified on the three phase contact line, the task is reformulated taking into account an additional chemical potential (or, in other words, the disjoining pressure of the liquid particles in thin liquid layers close to the three-phase contact line. This approach allows us to formulate the appropriate problem of mathematical physics in the consistent closed-form. The unique dependence of the disjoining pressure on the liquid film thickness and the decline angle of the free surface leads to degeneration of hydrodynamics equations on the three phase contact line, on the one hand, and to fulfilling the Yung condition, on the other one. The paper demonstrates application of the developed theory in the context of calculating liquid surface form at different movement velocities. The asymptotic relationships obtained from the results of numerical experiments allow us to describe the variation law of the apparent 'dynamic' contact angle versus rate of the falling liquid from the wetted surface in the way suitable for calculations.

  20. Decolorization of reactive textile dyes using water falling film dielectric barrier discharge.

    Science.gov (United States)

    Dojčinović, Biljana P; Roglić, Goran M; Obradović, Bratislav M; Kuraica, Milorad M; Kostić, Mirjana M; Nešić, Jelena; Manojlović, Dragan D

    2011-08-30

    Decolorization of reactive textile dyes Reactive Black 5, Reactive Blue 52, Reactive Yellow 125 and Reactive Green 15 was studied using advanced oxidation processes (AOPs) in a non-thermal plasma reactor, based on coaxial water falling film dielectric barrier discharge (DBD). Used initial dye concentrations in the solution were 40.0 and 80.0mg/L. The effects of different initial pH of dye solutions, and addition of homogeneous catalysts (H(2)O(2), Fe(2+) and Cu(2+)) on the decolorization during subsequent recirculation of dye solution through the DBD reactor, i.e. applied energy density (45-315kJ/L) were studied. Influence of residence time was investigated over a period of 24h. Change of pH values and effect of pH adjustments of dye solution after each recirculation on the decolorization was also tested. It was found that the initial pH of dye solutions and pH adjustments of dye solution after each recirculation did not influence the decolorization. The most effective decolorization of 97% was obtained with addition of 10mM H(2)O(2) in a system of 80.0mg/L Reactive Black 5 with applied energy density of 45kJ/L, after residence time of 24h from plasma treatment. Toxicity was evaluated using the brine shrimp Artemia salina as a test organism.

  1. Numerical Anaysis on Heat Transfer Enhancement by Waves on Falling Liquid Film

    Institute of Scientific and Technical Information of China (English)

    AkioMiyara

    2000-01-01

    Numerical simulations have been carried out for two dimensional wavy falling liquid films on a vertical wall.The algorithm of the simulation is based on MAC method and schemes for interfacial boundary conditions are modifed.Small artificial perturbations given at the inflow boundary grow rapidly and then the amplitude of the waves approaches to developed waves.Effects of the disturbance frequency on the wave development behavior and heat transfer characteristics are especially investigated.For low frequency,a disturbance wave develops to a solitary wave consisted of a large amplitude roll wave and small amplitude capillary waves,Increasing the frequency,the wave amplitude decreases and the capillary wave disappears.For further high frequency,the disturbance amplitude reduces along down stream.The heat transfer coefficient is enhanced by the surface wave and has a maximum at a certain frequency,The streamlines and the temperature comtoure contours are shown for various frequency waves and the heat transfer enhancement mechanism is clarified.

  2. Decolorization of reactive textile dyes using water falling film dielectric barrier discharge

    Energy Technology Data Exchange (ETDEWEB)

    Dojcinovic, Biljana P. [Institute of Chemistry, Technology and Metallurgy, Center of Chemistry, Studentski trg 12-16, 11000 Belgrade (Serbia); Roglic, Goran M. [Faculty of Chemistry, University of Belgrade, P.O. Box 158, 11000 Belgrade (Serbia); Obradovic, Bratislav M., E-mail: obrat@ff.bg.ac.rs [Faculty of Physics, University of Belgrade, P.O. Box 368, 11000 Belgrade (Serbia); Kuraica, Milorad M. [Faculty of Physics, University of Belgrade, P.O. Box 368, 11000 Belgrade (Serbia); Kostic, Mirjana M. [Faculty of Technology and Metallurgy, Department of Textile Engineering, Karnegijeva 4, 11000 Belgrade (Serbia); Nesic, Jelena; Manojlovic, Dragan D. [Faculty of Chemistry, University of Belgrade, P.O. Box 158, 11000 Belgrade (Serbia)

    2011-08-30

    Highlights: {yields} Decolorization of four reactive textile dyes using non-thermal plasma reactor. {yields} Influence of applied energy on decolorization. {yields} Effects of initial pH and addition of homogeneous catalysts. {yields} Toxicity evaluation using the brine shrimp as a test organism. - Abstract: Decolorization of reactive textile dyes Reactive Black 5, Reactive Blue 52, Reactive Yellow 125 and Reactive Green 15 was studied using advanced oxidation processes (AOPs) in a non-thermal plasma reactor, based on coaxial water falling film dielectric barrier discharge (DBD). Used initial dye concentrations in the solution were 40.0 and 80.0 mg/L. The effects of different initial pH of dye solutions, and addition of homogeneous catalysts (H{sub 2}O{sub 2}, Fe{sup 2+} and Cu{sup 2+}) on the decolorization during subsequent recirculation of dye solution through the DBD reactor, i.e. applied energy density (45-315 kJ/L) were studied. Influence of residence time was investigated over a period of 24 h. Change of pH values and effect of pH adjustments of dye solution after each recirculation on the decolorization was also tested. It was found that the initial pH of dye solutions and pH adjustments of dye solution after each recirculation did not influence the decolorization. The most effective decolorization of 97% was obtained with addition of 10 mM H{sub 2}O{sub 2} in a system of 80.0 mg/L Reactive Black 5 with applied energy density of 45 kJ/L, after residence time of 24 h from plasma treatment. Toxicity was evaluated using the brine shrimp Artemia salina as a test organism.

  3. Convective mass transfer from a submerged drop in a thin falling film

    CERN Document Server

    Landel, Julien R; McEvoy, H; Dalziel, Stuart B

    2015-01-01

    We study the fluid mechanics of removing a passive tracer contained in small, viscous drops attached to a flat inclined substrate using thin gravity-driven film flows. A convective mass transfer establishes across the drop-film interface and the tracer in the drop diffuses into the film flow. The Peclet number for the tracer in the film is large. The Peclet number Pe_d in the drop varies from 0.01 to 1. The characteristic transport time in the drop is much larger than in the film. We model the mass transfer of the tracer from the drop bulk into the film using an empirical model based on Newton's law of cooling. This model is supported by a theoretical model solving the quasi-steady 2D advection-diffusion equation in the film coupled with a time-dependent 1D diffusion equation in the drop. We find excellent agreement between our experimental data and the 2 models, which predict an exponential decrease in time of the tracer concentration in the drop. The results are valid for all drop and film Peclet numbers st...

  4. The Generalized Energy Equation and Instability in the Two-layer Barotropic Vortex

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The linear two-layer barotropic primitive equations in cylindrical coordinates are used to derive a generalized energy equation, which is subsequently applied to explain the instability of the spiral wave in the model. In the two-layer model, there are not only the generalized barotropic instability and the super highspeed instability, but also some other new instabilities, which fall into the range of the Kelvin-Helmholtz instability and the generalized baroclinic instability, when the upper and lower basic flows are different.They are perhaps the mechanisms of the generation of spiral cloud bands in tropical cyclones as well.

  5. Impact of internal transport on the convective mass transfer from a droplet into a submerging falling film

    Science.gov (United States)

    Landel, Julien R.; Thomas, Amalia; McEvoy, Harry; Dalziel, Stuart B.

    2015-11-01

    We investigate the convective mass transfer of dilute passive tracers contained in small viscous drops into a submerging falling film. This problem has applications in industrial cleaning, domestic dishwashers, and decontamination of hazardous material. The film Peclet number is very high, whereas the drop Peclet number varies from 0.1 to 1. The characteristic transport time in the drop is much larger than in the film. We model the mass transfer using an analogy with Newton's law of cooling. This empirical model is supported by an analytical model solving the quasi-steady two-dimensional advection-diffusion equation in the film that is coupled with a time-dependent one-dimensional diffusion equation in the drop. We find excellent agreement between our experimental data and the two models, which predict an exponential decrease in time of the drop concentration. The transport characteristic time is related to the drop diffusion time scale, as diffusion within the drop is the limiting process. Our theoretical model not only predicts the well-known relationship between the Sherwood number and the external Reynolds number in the case of a well-mixed drop Sh ~ Re1/3, it also predicts a correction in the case of a non-uniform drop concentration. The correction depends on Re, the film Schmidt number, the drop aspect ratio and the diffusivity ratio between the two phases. This prediction is in good agreement with experimental data. This material is based upon work supported by the Defense Threat Reduction Agency under Contract No. HDTRA1-12-D-0003-0001.

  6. The effect of superficial gas velocity on wavy films and its use in enhancing the performance of falling film reactors

    Energy Technology Data Exchange (ETDEWEB)

    Talens-Alesson, F.I. [TALENCO Chemical Engineering Consulting, Hospitalet de Llobregat (Spain)

    2000-07-01

    Mass transfer in co-current downward annular flow depends on the amount of liquid carried by the waves. The thickness of the wavy portion of the liquid film increases with the superficial gas velocity. By calculating superficial friction factors from simple pressure drop experiments, an estimate of the velocity at which the maximum development of waviness is achieved can be obtained, and optimized performance conditions can be found. (orig.)

  7. Film at Fall Meeting: Do-it-yourself flicks, Richard Alley preview

    Science.gov (United States)

    Adams, Mary Catherine

    2011-11-01

    Have you ever wished science had Hollywood star power? On Tuesday evening, 6 December, watch short science films and hear Hollywood filmmakers give advice to AGU scientists about these short films. Oceanographer-turned-filmmaker Randy Olson will host AGU's "The S Factor" video workshop along with screenwriter Sean Hood, cowriter of Halloween: Resurrection and the 2011 remake ofConan the Barbarian, and Jason Ensler, co-producer-director of TNT's Franklin & Bash. Olson is writer-director of the documentaries Flock of Dodos and Sizzle: A Global Warming Comedy and author of Don't Be Such a Scientist: Talking Substance in an Age of Style. The workshop starts at 7:00 P.M. in Moscone South, Room 300.

  8. Hydrodynamic Characterization of Harmonically Excited Falling-Films: A Detailed Experimental and Computational Study

    Science.gov (United States)

    Charogiannis, Alexandros; Denner, Fabian; van Wachem, Berend; Pradas, Marc; Kalliadasis, Serafim; Markides, Christos

    2016-11-01

    We investigate the hydrodynamic characteristics of harmonically excited liquid-films flowing down a 20circ; incline by simultaneous application of Particle Tracking Velocimetry and Planar Laser-Induced Fluorescence (PLIF) imaging, complemented by Direct Numerical Simulations. By simultaneously implementing the above two optical techniques, instantaneous and highly localised flow-rate data were also retrieved, based on which the effect of local film topology on the flow-field underneath the wavy interface is studied in detail. Our main result is that the instantaneous flow rate varies linearly with the instantaneous film-height, as confirmed by both experiments and simulations. Furthermore, both experimental and numerical flow-rate data are closely approximated by a simple analytical relationship, which is reported here for the first time, with only minor deviations. This relationship includes the wave speed c and mean flow-rate Q , both of which can be obtained by simple and inexpensive measurement techniques, thus allowing for spatiotemporally resolved flow-rate predictions to be made without requiring any knowledge of the full flow-field from below the wavy interface.

  9. Interfacial Stability in a Two-Layer Benard Problem.

    Science.gov (United States)

    1985-04-01

    STABILITY IN A TWO-LAYER BENARD PROBLEM Yuriko Renardy Technical Summary Report #2814 April 1985 I cti- Work Unit Number 2 - Physical Mathematics...34•"• -••’-’• ^ ••’••• VI , •• W -•- • •- ’•"• INTERFACIAL STABILITY IN A TWO-LAYER BENARD PROBLEM Yuriko Renardy I. INTRODUCTION Two layers of fluids are...Subtltl») INTERFACIAL STABILITY IN A TWO-LAYER BENARD PROBLEM 7. AUTMORf.; Yuriko Renardy »• PERFORMING ORGANIZATION NAME AND ADDRESS

  10. Modeling and Optimizing of Producing Recycled PET from Fabrics Waste via Falling Film-Rotating Disk Combined Reactor

    Directory of Open Access Journals (Sweden)

    Dan Qin

    2017-01-01

    Full Text Available Recycling and reusing of poly (ethylene terephthalate (PET fabrics waste are essential for reducing serious waste of resources and environmental pollution caused by low utilization rate. The liquid-phase polymerization method has advantages of short process flow, low energy consumption, and low production cost. However, unlike prepolymer, the material characteristics of PET fabrics waste (complex composition, high intrinsic viscosity, and large quality fluctuations make its recycling a technique challenge. In this study, the falling film-rotating disk combined reactor is proposed, and the continuous liquid-phase polymerization is modeled by optimizing and correcting existing models for the final stage of PET polymerization to improve the product quality in plant production. Through modeling and simulation, the weight analysis of indexes closely related to the product quality (intrinsic viscosity, carboxyl end group concentration, and diethylene glycol content was investigated to optimize the production process in order to obtain the desired polymer properties and meet specific product material characteristics. The model could be applied to other PET wastes (e.g., bottles and films and extended to investigate different aspects of the recycling process.

  11. Asymptotic Modelling of Crystallisation in Two Layers Systems. Application to Methane Hydrate Formation in Batch Reactor.

    OpenAIRE

    Cournil, Michel; Herri, Jean-Michel

    2002-01-01

    6 pages; This paper proposes to re-visit the problem of gas-liquid crystallization in the framework of a two-layer model and with the help of data coming from experiments on methane hydrate crystallization in a semi-batch reactor. Preliminary quantitative discussion of the order of magnitude of different effects makes possible realistic simplifications in the theoretical models. In particular, the role of the interfacial film is clearly defined. As previous authors did, we use a formulation i...

  12. 氨水溶液降膜蒸发实验%Experiment of ammonia water falling film evaporation

    Institute of Scientific and Technical Information of China (English)

    骆超; 龚宇烈; 马伟斌

    2011-01-01

    An experimental investigation of vertical out-tube falling film heat transfer with different inlet spray densities of ammonia water mixture and inlet hot water temperatures was conducted.The falling film evaporator had a total height of 6000mm and the cycling working fluids were high concentration 60% and 50% ammonia water.We mainly studied the influence of spray density and inlet temperature of hot water on heat transfer coefficient,ammonia vapor amount and evaporation pressure.The experiment showed that heat transfer coefficient and ammonia vapor amount increased first and then decreased with increasing inlet spray density.The higher the hot water temperature,the higher the evaporation pressure.Heat transfer coefficient increased lineany with increasing hot water temperature.The experimental heat transfer coefficient of ammonia water solution was significantly higher than that of water reported in literature.For 50% water,optimum spray density was between 0.2200 and 0.2500 kg/(m·s);for 60% ammonia water,optimum spray density was between 0.2600 and 0.2900 kg/(m·s).In this experiment,heat transfer performance of 60% ammonia water was better than 50% ammonia water.%发生器和吸收器的传热性能是影响制冷机组和双工质发电机组做功效率的关键因素,为了提高中低温地热(余热)在热泵机组和地热双工质发电系统中的利用效率,本文选用50%和60%的氨水溶液作为循环工质,对约6 m长的竖管降膜蒸发器的传热特性进行实验研究,分别讨论喷淋密度和热水温度对垂直降膜蒸发器的传热系数、氨蒸气量和蒸发压力的影响。结果表明,降膜蒸发器的传热系数和氨蒸气量随喷淋密度的增加先增大后减小,传热系数和蒸发压力随着热源温度的增大而增加;50%和60%的氨水溶液喷淋密度最佳值分别在0.2200~0.2500 k

  13. Theoretical Permeability of Two-layered Nonwoven Geotextiles

    Institute of Scientific and Technical Information of China (English)

    LIU Li-fang; CHU Cai-yuan

    2006-01-01

    The two-layered nonwoven geotextile, which consists of a layer constructed with fine fibers for providing optimal filtration characteristics and another layer constructed with coarse fibers for providing the required mechanical properties, is desirable for drainage and filtration system.Based on Darcy's law and drag force theory, a mathematical model on vertical permeability coefficient of two-layered nonwoven geotextile is estabilished. Comparison with experimental results shows that the present model possesses 83.6% accuracy for needle-punched two-layered nonwoven geotextiles. And experimental results also show that with the increasing of needle density the vertical permeability coefficient of two-layered nonwoven geotextiless firstly decreases and then increases, reaching the smallest value at 470 p/cm2.

  14. Prediction of Heat Transfer Characteristics of Binary Refrigerant Mixtures in a Falling Film Type Plate-fin Evaporator

    Science.gov (United States)

    Yara, Tomoyasu; Koyama, Shigeru

    This paper deals with the characteristics of heat transfer and pressure drop of R 22, R 134a pure refrigerant and R 134a/R123 refrigerant mixtures in a falling film type plate-fin evaporator. The refrigerants have been tested in the ranges of heat flux from 3 to 20 kW/m2 and mass velocity from 50 to 100 kg/m2s. It is clarified that heat transfer characteristics of evaporation in the present experimental range are not affected by shear stress. Taking the fin efficiency into consideration, a correlation equation of heat transfer coefficient is proposed. The characteristic of pressure drop is also proposed by modifying friction factor of Soliman's equation. Furthermore, a prediction model for evaporation of mixtures in a plate fin heat exchanger is developed based on the assumption that the phase equilibrium in a cross-section of the refrigerant path is established. The prediction results are in good agreement with the experimental data.

  15. Two-layer sheet of gelatin: A new topical hemostatic agent.

    Science.gov (United States)

    Takagi, Toshitaka; Tsujimoto, Hiroyuki; Torii, Hiroko; Ozamoto, Yuki; Hagiwara, Akeo

    2016-11-02

    Uncontrolled surgical bleeding is associated with increased morbidity, mortality, and hospital cost. Topical hemostatic agents available today have problems controlling hemostatic effects; furthermore, their handling is difficult and they are unsafe. We devised a new hemostatic agent comprising gelatin sponge and film designed to be applied to the bleeding site, thereby creating a topical hemostatic agent made of gelatin alone. The gelatin was prepared by alkali treatment to eliminate viral activity. Hemostatic effects, surgical handling, and tissue reactions of the materials, namely a two-layer sheet of gelatin, TachoSil, and gelatin sponge, were evaluated using 21 dogs' spleens. The two-layer gelatin sheet and gelatin sponge exhibited superior hemostatic effects (100% hemostasis completed) compared with TachoSil (0-17% hemostasis). The gelatin matrix immediately absorbed blood flowing from wounds and activated the autologous components in the absorbed blood that promoted coagulation at the bleeding site. The two-layer gelatin sheet had the best surgical handling among the evaluated materials. Materials made of gelatin were associated with fewer inflammatory reactions compared with materials of TachoSil. The two-layer sheet of gelatin is a useful topical agent because of its superior hemostatic effects and usability, and is associated with a lower risk of transmitting diseases and inflammatory reactions. Copyright © 2016. Published by Elsevier Taiwan.

  16. Improved efficient routing strategy on two-layer complex networks

    Science.gov (United States)

    Ma, Jinlong; Han, Weizhan; Guo, Qing; Zhang, Shuai; Wang, Junfang; Wang, Zhihao

    2016-10-01

    The traffic dynamics of multi-layer networks has become a hot research topic since many networks are comprised of two or more layers of subnetworks. Due to its low traffic capacity, the traditional shortest path routing (SPR) protocol is susceptible to congestion on two-layer complex networks. In this paper, we propose an efficient routing strategy named improved global awareness routing (IGAR) strategy which is based on the betweenness centrality of nodes in the two layers. With the proposed strategy, the routing paths can bypass hub nodes of both layers to enhance the transport efficiency. Simulation results show that the IGAR strategy can bring much better traffic capacity than the SPR and the global awareness routing (GAR) strategies. Because of the significantly improved traffic performance, this study is helpful to alleviate congestion of the two-layer complex networks.

  17. Synchronization of Stochastic Two-Layer Geophysical Flows

    Institute of Scientific and Technical Information of China (English)

    HAN Yongqian

    2011-01-01

    In this paper, the two-layer quasigeostrophic flow model under stochastic wind forcing is considered. It is shown that when the layer depth or density difference across the layers tends to zero, the dynamics on both layers synchronizes to an averaged geophysical flow model.

  18. Linear waves in two-layer fluids over periodic bottoms

    NARCIS (Netherlands)

    Yu, J.; Maas, L.R.M.

    2016-01-01

    A new, exact Floquet theory is presented for linear waves in two-layer fluidsover a periodic bottom of arbitrary shape and amplitude. A method of conformaltransformation is adapted. The solutions are given, in essentially analytical form, forthe dispersion relation between wave frequency and general

  19. Linear waves in two-layer fluids over periodic bottoms

    NARCIS (Netherlands)

    Yu, Jie; Maas, L.R.M.

    2016-01-01

    A new, exact Floquet theory is presented for linear waves in two-layer fluids over a periodic bottom of arbitrary shape and amplitude. A method of conformal transformation is adapted. The solutions are given, in essentially analytical form, for the dispersion relation between wave frequency and gene

  20. Pattern Synchronization in a Two-Layer Neuronal Network

    Institute of Scientific and Technical Information of China (English)

    SUN Xiao-Juan; LU Qi-Shao

    2009-01-01

    Pattern synchronization in a two-layer neuronal network is studied.For a single-layer network of Rulkov map neurons,there are three kinds of patterns induced by noise.Additive noise can induce ordered patterns at some intermediate noise intensities in a resonant way;however,for small and large noise intensities there exist excitable patterns and disordered patterns,respectively.For a neuronal network coupled by two single-layer networks with noise intensity differences between layers,we find that the two-layer network can achieve synchrony as the interlayer coupling strength increases.The synchronous states strongly depend on the interlayer coupling strength and the noise intensity difference between layers.

  1. Training two-layered feedforward networks with variable projection method.

    Science.gov (United States)

    Kim, C T; Lee, J J

    2008-02-01

    The variable projection (VP) method for separable nonlinear least squares (SNLLS) is presented and incorporated into the Levenberg-Marquardt optimization algorithm for training two-layered feedforward neural networks. It is shown that the Jacobian of variable projected networks can be computed by simple modification of the backpropagation algorithm. The suggested algorithm is efficient compared to conventional techniques such as conventional Levenberg-Marquardt algorithm (LMA), hybrid gradient algorithm (HGA), and extreme learning machine (ELM).

  2. Electromagnetic Scattering in a Two-layered Medium

    Institute of Scientific and Technical Information of China (English)

    FENG LI-XIN; LI YUAN; Ma Fu-ming

    2011-01-01

    The object of this paper is to investigate the three-dimensional electro-magnetic scattering problems in a two-layered background medium.These problems have an important application in today's technology,such as to detect objects that are buried in soil.Here,we model both the exterior impedance problem and the inhomogeneous medium problem in R3.We establish uniqueness and existence for the solution of the two scattering problems,respectively.

  3. Two-Layer Feedback Neural Networks with Associative Memories

    Institute of Scientific and Technical Information of China (English)

    WU Gui-Kun; ZHAO Hong

    2008-01-01

    We construct a two-layer feedback neural network by a Monte Carlo based algorithm to store memories as fixed-point attractors or as limit-cycle attractors. Special attention is focused on comparing the dynamics of the network with limit-cycle attractors and with fixed-point attractors. It is found that the former has better retrieval property than the latter. Particularly, spurious memories may be suppressed completely when the memories are stored as a long-limit cycle. Potential application of limit-cycle-attractor networks is discussed briefly.

  4. Tidal modulation of two-layer hydraulic exchange flows

    Directory of Open Access Journals (Sweden)

    L. M. Frankcombe

    2006-11-01

    Full Text Available Time-dependent, two layer hydraulic exchange flow is studied using an idealised shallow water model. It is found that barotropic time-dependent perturbations, representing tidal forcing, increase the baroclinic exchange flux above the steady hydraulic limit, with flux increasing monotonically with tidal amplitude (measured either by height or flux amplitude over a tidal period. Exchange flux also depends on the non-dimensional tidal period, γ, which was introduced by Helfrich (1995. Resonance complicates the relationship between exchange flux and height amplitude, but, when tidal strength is characterised by flux amplitude, exchange flux is a monotonic function of γ.

  5. Baroclinic instability in the two-layer model. Interpretations

    Energy Technology Data Exchange (ETDEWEB)

    Egger, Joseph [Meteorological Inst., Univ. of Munich (Germany)

    2009-10-15

    Two new interpretations of the wellknown instability criterion of the two-layer model of baroclinic instability are given whereby also a slight generalization of this model is introduced by admitting an interface on top with a reduced gravity g. It is found that instability sets in when the horizontal potential temperature advection by the barotropic mode becomes more important than the vertical temperature advection due to this mode. The second interpretation is based on potential vorticity (PV) thinking. Instability implies a dominance of the vertical PV coupling coefficient compared to horizontal mean state PV advection generated at the same level. The interface damps with decreasing g. (orig.)

  6. Interference testing of a two-layer commingled reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Onur, M.; Reynolds, A.C. (Tulsa Univ., OK (USA))

    1989-12-01

    A two-well system in an infinite-acting, commingled, two-layer reservoir is considered. One well, the active well, is produced at a constant total rate, and the second well, the observation well, is shut in at all times. An analytical solution in Laplace space is presented, and the parametric groups that uniquely determine the pressure and rate solutions are identified. Results regarding crossflow through the observation well are presented. Conditions under which the line-source solution can be used to analyze observations-well pressure data are delineated.

  7. Investigations of Two-Layer Earth Parameters at Low Voltage: Measurements and Calculations

    Directory of Open Access Journals (Sweden)

    E. Ramdan

    2009-01-01

    Full Text Available Problem statement: The two-layer soil model at low magnitude voltage is assumed to be accurate for the measurement and calculation of the earth resistance of a combined grid-multiple rods electrode. The aim of this study is to measure and calculate the earth resistance of a combined grid-multiple rods electrode buried in a two-layer soil and to confirm the simplicity and accuracy of the used formula. Approach: Soil resistivity was measured using Wenner four point method. Advanced earth resistivity measurement interpretation techniques which include graphical curve matching based on master curves and an advanced computer program based on a genetic algorithm are used in this study. Results: Based on the resistivity data, the earth resistance value was calculated using the formulas obtained from the literature. Measurements of the earth resistance of the earthing system were also conducted using the fall of potential method. Conclusion/Recommendations: A very good agreement was obtained between the measured and calculated earth resistance values. This research is the first time ever conducted where the measured earth resistance values are compared directly with the calculated earth values.

  8. Spatial frequency domain spectroscopy of two layer media

    Science.gov (United States)

    Yudovsky, Dmitry; Durkin, Anthony J.

    2011-10-01

    Monitoring of tissue blood volume and oxygen saturation using biomedical optics techniques has the potential to inform the assessment of tissue health, healing, and dysfunction. These quantities are typically estimated from the contribution of oxyhemoglobin and deoxyhemoglobin to the absorption spectrum of the dermis. However, estimation of blood related absorption in superficial tissue such as the skin can be confounded by the strong absorption of melanin in the epidermis. Furthermore, epidermal thickness and pigmentation varies with anatomic location, race, gender, and degree of disease progression. This study describes a technique for decoupling the effect of melanin absorption in the epidermis from blood absorption in the dermis for a large range of skin types and thicknesses. An artificial neural network was used to map input optical properties to spatial frequency domain diffuse reflectance of two layer media. Then, iterative fitting was used to determine the optical properties from simulated spatial frequency domain diffuse reflectance. Additionally, an artificial neural network was trained to directly map spatial frequency domain reflectance to sets of optical properties of a two layer medium, thus bypassing the need for iteration. In both cases, the optical thickness of the epidermis and absorption and reduced scattering coefficients of the dermis were determined independently. The accuracy and efficiency of the iterative fitting approach was compared with the direct neural network inversion.

  9. Nonlinear topographic effects in two-layer flows

    Directory of Open Access Journals (Sweden)

    Peter George Baines

    2016-02-01

    Full Text Available We consider the nature of non-linear flow of a two-layer fluid with a rigid lid over a long obstacle, such that the flow may be assumed to be hydrostatic. Such flows can generate hydraulic jumps upstream, and the model uses a new model of internal hydraulic jumps, which results in corrections to flows that have been computed using earlier models of jumps that are now known to be incorrect. The model covers the whole range of ratios of the densities of the two fluids, and is not restricted to the Boussinesq limit. The results are presented in terms of flow types in various regions of a Froude number-obstacle height (F0 – Hm diagram, in which the Froude number F0 is based on the initial flow conditions. When compared with single-layer flow, and some previous results with two layers, some surprising and novel patterns emerge on these diagrams. Specifically, in parts of the diagram where the flow may be supercritical (F0 > 1, there are regions where hysteresis may occur, implying that the flow may have two and sometimes three multiple flow states for the same conditions (i.e. values of F0 and Hm.

  10. Two-Layer Elastographic 3-D Traction Force Microscopy

    Science.gov (United States)

    Álvarez-González, Begoña; Zhang, Shun; Gómez-González, Manuel; Meili, Ruedi; Firtel, Richard A.; Lasheras, Juan C.; Del Álamo, Juan C.

    2017-01-01

    Cellular traction force microscopy (TFM) requires knowledge of the mechanical properties of the substratum where the cells adhere to calculate cell-generated forces from measurements of substratum deformation. Polymer-based hydrogels are broadly used for TFM due to their linearly elastic behavior in the range of measured deformations. However, the calculated stresses, particularly their spatial patterns, can be highly sensitive to the substratum’s Poisson’s ratio. We present two-layer elastographic TFM (2LETFM), a method that allows for simultaneously measuring the Poisson’s ratio of the substratum while also determining the cell-generated forces. The new method exploits the analytical solution of the elastostatic equation and deformation measurements from two layers of the substratum. We perform an in silico analysis of 2LETFM concluding that this technique is robust with respect to TFM experimental parameters, and remains accurate even for noisy measurement data. We also provide experimental proof of principle of 2LETFM by simultaneously measuring the stresses exerted by migrating Physarum amoeboae on the surface of polyacrylamide substrata, and the Poisson’s ratio of the substrata. The 2LETFM method could be generalized to concurrently determine the mechanical properties and cell-generated forces in more physiologically relevant extracellular environments, opening new possibilities to study cell-matrix interactions.

  11. Design and analysis of two-layer anonymous communication system

    Institute of Scientific and Technical Information of China (English)

    WANG Wei-ping; WANG Jian-xin

    2007-01-01

    A new architecture for scalable anonymous communication system(SACS) was proposed. The users were divided into several subgroups managed by different sub-blenders, and all sub-blenders were managed by the main-blender using two layers management scheme. The identity information of members are distributed on different sub-blenders, which makes each member keep much less information and network overload greatly reduce. The anonymity and the overhead of the new scheme were analyzed and compared with that of Crowds, which shows the cost of storage and network overhead for the new scheme largely decreases while the anonymity is little degraded. The experiment results also show that the new system architecture is well scalable. The ratio of management cost of SACS to that of Crowds is about 1:25 while the value of P(I|H1+) only increases by 0.001-0.020, which shows that SACS keeps almost the same anonymity with Crowds.

  12. A simple physical model for steam absorption into a falling film of aqueous lithium bromide solution on a horizontal tube

    Science.gov (United States)

    Auracher, Hein; Wohlfeil, Arnold; Ziegler, Felix

    2008-03-01

    For one horizontal tube in an absorber the Nusselt solution for film thickness and velocity distribution was applied, assuming steady state in heat transfer and a semi-infinite body’s concentration profile with unsteady state mass transfer. The model was applied to the absorption of steam into aqueous lithium bromide in absorption chillers. The results are compared to published experimental values and show fair agreement.

  13. In vivo spatial frequency domain spectroscopy of two layer media

    Science.gov (United States)

    Yudovsky, Dmitry; Nguyen, John Quan M.; Durkin, Anthony J.

    2012-10-01

    Monitoring of tissue blood volume and local oxygen saturation can inform the assessment of tissue health, healing, and dysfunction. These quantities can be estimated from the contribution of oxyhemoglobin and deoxyhemoglobin to the absorption spectrum of the dermis. However, estimation of blood related absorption in skin can be confounded by the strong absorption of melanin in the epidermis and epidermal thickness and pigmentation varies with anatomic location, race, gender, and degree of disease progression. Therefore, a method is desired that decouples the effect of melanin absorption in the epidermis from blood absorption in the dermis for a large range of skin types and thicknesses. A previously developed inverse method based on a neural network forward model was applied to simulated spatial frequency domain reflectance of skin for multiple wavelengths in the near infrared. It is demonstrated that the optical thickness of the epidermis and absorption and reduced scattering coefficients of the dermis can be determined independently and with minimal coupling. Then, the same inverse method was applied to reflectance measurements from a tissue simulating phantom and in vivo human skin. Oxygen saturation and total hemoglobin concentrations were estimated from the volar forearms of weakly and strongly pigmented subjects using a standard homogeneous model and the present two layer model.

  14. Numerical Simulation Using Boundary Element Method of the Mechanism to Enhance Heat Transport by Solitary Wave on Falling Thin Liquid Films

    Institute of Scientific and Technical Information of China (English)

    Wen-QingLu

    1993-01-01

    A boundary element method has been developed for analysing heat transport phenomena in solitary wave on falling thin liquid films at high Reynolds numbers.The divergence theorem is applied to the non-linear convective volume integral of the boundary element formulation with the pressure penalty function.Consequently,velocity and temperature gradients are dliminated.and the complete formulation is written in terms of velocity and temperature,This provides considerable reduction is storage and computational requirements while improving accuracy.The non-linear equation systems of boundary element discretization are solved by the quasi-Nweton iterative scheme with Broyden's update.The streamline maps and the temperature distributions in solitary wave and wavy film flow have been obtained,and the variations of Nusselt numbers along the wall-liquid interface are also given.There are large cross-flow velocities and S-shape temperature distributions in the recirculating region of solitary wave.This special flow and thermal process can be a mechanism to enhance heat transport.

  15. High Performance Graphite Falling Film Absorber%高性能石墨降膜吸收器

    Institute of Scientific and Technical Information of China (English)

    姚松年

    2016-01-01

    A brief introduction to which is considered as further innovation and development of a industrial production technological revolution of graphite falling iflm absorber, performance and e'cacy of domestic tubular, graphite block heat absorber has been further improved, reached the international advanced level.%简要介绍对曾被誉为是盐酸工业生产的一次技术革命的石墨降膜吸收器的进一步创新开发,使国产列管式、圆块式石墨降膜吸收器的性能与功效得到进一步提高,达国际先进水平。

  16. Development of a fully integrated falling film microreactor for gas-liquid-solid biotransformation with surface immobilized O2 -dependent enzyme.

    Science.gov (United States)

    Bolivar, Juan M; Krämer, Christina E M; Ungerböck, Birgit; Mayr, Torsten; Nidetzky, Bernd

    2016-09-01

    Microstructured flow reactors are powerful tools for the development of multiphase biocatalytic transformations. To expand their current application also to O2 -dependent enzymatic conversions, we have implemented a fully integrated falling film microreactor that provides controllable countercurrent gas-liquid phase contacting in a multi-channel microstructured reaction plate. Advanced non-invasive optical sensing is applied to measure liquid-phase oxygen concentrations in both in- and out-flow as well as directly in the microchannels (width: 600 μm; depth: 200 μm). Protein-surface interactions are designed for direct immobilization of catalyst on microchannel walls. Target enzyme (here: d-amino acid oxidase) is fused to the positively charged mini-protein Zbasic2 and the channel surface contains a negatively charged γ-Al2 O3 wash-coat layer. Non-covalent wall attachment of the chimeric Zbasic2 _oxidase resulted in fully reversible enzyme immobilization with fairly uniform surface coverage and near complete retention of biological activity. The falling film at different gas and liquid flow rates as well as reactor inclination angles was shown to be mostly wavy laminar. The calculated film thickness was in the range 0.5-1.3 × 10(-4)  m. Direct O2 concentration measurements at the channel surface demonstrated that the liquid side mass transfer coefficient (KL ) for O2 governed the overall gas/liquid/solid mass transfer and that the O2 transfer rate (≥0.75 mM · s(-1) ) vastly exceeded the maximum enzymatic reaction rate in a wide range of conditions. A value of 7.5 (±0.5) s(-1) was determined for the overall mass transfer coefficient KL a, comprising a KL of about 7 × 10(-5)  m · s(-1) and a specific surface area of up to 10(5)  m(-1) . Biotechnol. Bioeng. 2016;113: 1862-1872. © 2016 Wiley Periodicals, Inc.

  17. Designing Two-Layer Optical Networks with Statistical Multiplexing

    Science.gov (United States)

    Addis, B.; Capone, A.; Carello, G.; Malucelli, F.; Fumagalli, M.; Pedrin Elli, E.

    The possibility of adding multi-protocol label switching (MPLS) support to transport networks is considered an important opportunity by telecom carriers that want to add packet services and applications to their networks. However, the question that arises is whether it is suitable to have MPLS nodes just at the edge of the network to collect packet traffic from users, or also to introduce MPLS facilities on a subset of the core nodes in order to exploit packet switching flexibility and multiplexing, thus providing induction of a better bandwidth allocation. In this article, we address this complex decisional problem with the support of a mathematical programming approach. We consider two-layer networks where MPLS is overlaid on top of transport networks-synchronous digital hierarchy (SDH) or wavelength division multiplexing (WDM)-depending on the required link speed. The discussions' decisions take into account the trade-off between the cost of adding MPLS support in the core nodes and the savings in the link bandwidth allocation due to the statistical multiplexing and the traffic grooming effects induced by MPLS nodes. The traffic matrix specifies for each point-to-point request a pair of values: a mean traffic value and an additional one. Using this traffic model, the effect of statistical multiplexing on a link allows the allocation of a capacity equal to the sum of all the mean values of the traffic demands routed on the link and only the highest additional one. The proposed approach is suitable to solve real instances in reasonable time.

  18. Falling chains

    Science.gov (United States)

    Wong, Chun Wa; Yasui, Kosuke

    2006-06-01

    The one-dimensional fall of a folded chain with one end suspended from a rigid support and a chain falling from a resting heap on a table is studied. Because their Lagrangians contain no explicit time dependence, the falling chains are conservative systems. Their equations of motion are shown to contain a term that enforces energy conservation when masses are transferred between subchains. We show that Cayley's 1857 energy nonconserving solution for a chain falling from a resting heap is incorrect because it neglects the energy gained when a link leaves a subchain. The maximum chain tension measured by Calkin and March for the falling folded chain is given a simple if rough interpretation. Other aspects of the falling folded chain are briefly discussed.

  19. PENGARUH SUHU DAN LAMA PROSES SULFONASI DALAM PROSES PRODUKSI METHYL ESTER SULFONIC ACID (MESA MENGGUNAKAN SINGLE TUBE FALLING FILM REACTOR (STFR

    Directory of Open Access Journals (Sweden)

    Siti Mujdalipah

    2013-03-01

    Full Text Available Effects of Temperature and Sulfonation Time on Methyl Ester Sulfonic Acid (MESA Production Process usingSingle Tube Falling Film Reactor (STFR Siti Mujdalipah, Erliza Hambali, Ani Suryani, Edi Zulchaidir ABSTRAK Methyl Ester Sulfonic Acid (MESA merupakan produk antara dari surfaktan Metil Ester Sulfonat (MES. MESmemiliki beragam aplikasi dalam produk personal care, pencuci dan pembersih, dan untuk Enhanced Oil Recovery(EOR. Proses produksi MESA menggunakan gas SO3 dalam Single Tube Falling Film Reactor (STFR merupakanteknologi yang umum digunakan. Kajian ini bertujuan untuk mendapatkan kondisi proses sulfonasi metil ester oleinterbaik menggunakan gas SO3 dalam STFR. Kajian dilakukan dalam tiga tahap, yaitu tahap penelitian, tahap analisis,dan tahap pengolahan data. Tahap produksi MESA terdiri dari pembuatan metil ester (ME dari olein minyak sawit dankajian pengaruh suhu dan lama proses sulfonasi. Tahap analisis meliputi analisis sifat Þ siko kimia olein minyak sawit,analisa sifat Þ siko kimia ME olein sawit, dan analisis sifat Þ siko kimia MESA olein sawit. Kajian pengaruh suhu danlama proses sulfonasi terhadap proses sulfonasi metil ester olein terdiri dari suhu 70, 90, dan 110 oC dan lama prosessulfonasi 30, 60, dan 90 menit. Analisis varian pada !=0,01 menunjukan bahwa lama proses sulfonasi berpengaruh nyataterhadap kadar bahan aktif. Analisis varian pada !=0,01 juga menunjukan bahwa lama proses sulfonasi berpengaruhnyata terhadap nilai pH, bilangan asam, bilangan iod, dan kemampuan MESA dalam menurunkan tegangan antarmuka(IFT, Interfacial Tension antara air formasi dan minyak bumi. Proses sulfonasi terbaik dicapai pada suhu sulfonasi 90oCdan lama proses sulfonasi 90 menit. Kondisi proses sulfonasi terbaik dapat menghasilkan MESA dengan karakteristikkadar bahan aktif 31,44%, pH 2,66, bilangan asam 24,88 ml NaOH/g sampel, bilangan iod 11,95 mg I/g sampel, danmemiliki kemampuan menurunkan IFT antara air formasi dan minyak bumi dari 30 dyne

  20. Ultraefficient reduced model for countercurrent two-layer flows

    Science.gov (United States)

    Lavalle, Gianluca; Vila, Jean-Paul; Lucquiaud, Mathieu; Valluri, Prashant

    2017-01-01

    We investigate the dynamics of two superposed layers with density contrast flowing countercurrent inside a channel, when the lower layer is much thinner than the wavelength of interfacial waves. We apply a low-dimensional film model to the bottom (heavier) layer and introduce a fast and efficient method to predict the onset of flow reversal in this phase. We study three vertical scenarios with different applied pressure gradients and compare the temporal growth rates of linear and weakly nonlinear waves to the Orr-Sommerfeld problem and to the weakly nonlinear theory, respectively. At the loading point, i.e., when a large wave hump stands at the interface, our spatiotemporal analysis shows that the system is absolutely unstable. We then present profiles of nonlinear saturated waves, pressure field, and streamline distribution in agreement with direct numerical simulation. The reduced model presented here allows us to explore the effect of the upper-layer speed on the wave pattern, showing that the wave profile is very sensitive when the mean film thickness, rather than the liquid flow rate, is maintained constant in the simulation. In addition, we show the strong effect of surface tension on both the maximum wave hump and the crest steepness before the loading point. Finally, we reveal how the nonlinear wave speed affects the vortex distribution within the lower layer by analyzing the stream function under different scenarios.

  1. Photo-Fenton degradation of phenol, 2,4-dichlorophenoxyacetic acid and 2,4-dichlorophenol mixture in saline solution using a falling-film solar reactor.

    Science.gov (United States)

    Luna, Airton J; Nascimento, Cláudio A O; Foletto, Edson Luiz; Moraes, José E F; Chiavone-Filhoe, Osvaldo

    2014-01-01

    In this work, a saline aqueous solution of phenol, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenol (2,4-DCP) was treated by the photo-Fenton process in a falling-film solar reactor. The influence of the parameters such as initial pH (5-7), initial concentration of Fe2+ (1-2.5mM) and rate of H202 addition (1.87-3.74mmol min-1) was investigated. The efficiency of photodegradation was determined from the removal of dissolved organic carbon (DOC), described by the species degradation of phenol, 2,4-D and 2,4-DCP. Response surface methodology was employed to assess the effects of the variables investigated, i.e. [Fe2+], [H202] and pH, in the photo-Fenton process with solar irradiation. The results reveal that the variables' initial concentration of Fe2+ and H202 presents predominant effect on pollutants' degradation in terms of DOC removal, while pH showed no influence. Under the most adequate experimental conditions, about 85% DOC removal was obtained in 180 min by using a reaction system employed here, and total removal of phenol, 2,4- and 2,4-DCP mixture in about 30min.

  2. Palladium Electrodeposition onto Pt(100): Two-Layer Underpotential Deposition.

    Science.gov (United States)

    Previdello, Bruno A F; Sibert, Eric; Maret, Mireille; Soldo-Olivier, Yvonne

    2017-03-07

    Electrodeposition of the first Pd layers onto Pt(100) was investigated using cyclic voltammetry at a low scan rate (0.1 mV·s(-1)). Ultrathin films were characterized by cyclic voltammetry in 0.1 M H2SO4 solution and with ex situ AFM (atomic force microscopy). For the first time, we evidenced the underpotential character of the deposition of the first two Pd layers, characterized by a two-step mechanism, each step corresponding to the deposition of a complete Pd atomic layer. For thicker deposits, especially above 10 monolayers as equivalent thickness, the electrochemical characterization displays a strong irreversibility and a broadening of the adsorption/desorption peaks, associated with a reduction of long-range ordered flat areas. Ex situ AFM images are in agreement with this description. They show rough thick deposits and the growth of (100)-oriented rectangular shaped islands with their sides aligned with the two [011] and [0-11] perpendicular directions of the (100) Pt surface.

  3. Falling chains

    CERN Document Server

    Wong, C W; Wong, Chun Wa; Yasui, Kosuke

    2006-01-01

    The one-dimensional falling motion of a bungee chain suspended from a rigid support and of a chain falling from a resting heap on a table is studied. Their Lagrangians are found to contain no explicit time dependence. As a result, these falling chains are conservative systems. Each of their Lagrange's equations of motion is shown to contain a term that enforces energy conservation when masses are transferred between subchains. We show in particular that Cayley's 1857 energy nonconserving solution for a chain falling from a resting heap is incorrect because it neglects the energy gained when the transferred link is emitted by the emitting subchain. The maximum chain tension measured by Calkin and March for the falling bungee chain is given a simple if rough interpretation. In the simplified one-dimensional treatment, the kinetic energy of the center of mass of the falling bungee chain is found to be converted by the chain tension at the rigid support into the internal kinetic energy of the chain. However, as t...

  4. 垂直管氨水降膜吸收传质研究%Mass Transfer Study of Ammonia-water Falling-film Absorption in Vertical Tube

    Institute of Scientific and Technical Information of China (English)

    徐振中; 夏再忠; 林芃; 郭沛民; 王如竹

    2012-01-01

    Absorber is the key component of Ammonia-water absorption refrigeration. This study simulate the falling film adiabatic absorption to analyse the characteristics of mass absorption and compare the simulated result with the experiment result. The error of the simulated value of mass transfer rate comparing to the experiment value is less than 20%.Besides the experiment shows that subcooling of weak solution before absorption can promote the mass absorption. In experiment, cooled absorption with subcooling improve the mass absorptive rate by 132%.%吸收器是影响氨水吸收式制冷系统的关键部件.对常用的垂直管氨水降膜吸收器进行绝热吸收模拟分析,并将模拟分析结果与实验结果进行了对比.在此基础上,通过实验进一步研究了稀溶液进口过冷和外部吸收冷却对吸收传质的影响,得到稀溶液进口过冷能够促进吸收传质的结论.结果表明:氨水吸收式制冷传质率的模拟结果与实验结果的偏差在20%以内,在冷却吸收和进口过冷的实验测试工况下,吸收传质率提高了132%.

  5. [Accidental falls].

    Science.gov (United States)

    Inokuchi, Koichi

    2013-06-01

    Falls are common cause of injuries among elderly people, and fractures are the most serious consequence of falls. For seniors, hip fractures are the second major cause of bedridden. The feature and acute care of head injury, spinal cord injury, vertebrae fracture, and hip fracture are described. Just had fracture fixation, the patient can not go back to the original ADL. In order not to become bedridden, both medication and physical examination are important based on the new disease concept of locomotive syndrome. To do so, requires hospital and clinic cooperation. Sufficient cooperation is not currently possible, and spread of liaison service is essential.

  6. Reflected light intensity profile of two-layer tissues: phantom experiments.

    Science.gov (United States)

    Ankri, Rinat; Taitelbaum, Haim; Fixler, Dror

    2011-08-01

    Experimental measurements of the reflected light intensity from two-layer phantoms are presented. We report, for the first time, an experimental observation of a typical reflected light intensity behavior for the two-layer structure characterized by two different slopes in the reflected light profile of the irradiated tissue. The point in which the first slope changes to the second slope, named as the crossover point, depends on the upper layer thickness as well as on the ratio between the absorption coefficients of the two layers. Since similar experiments from one-layer phantoms present a monotonic decay behavior, the existence and the location of the crossover point can be used as a diagnostic fingerprint for two-layer tissue structures. This pertains to two layers with greater absorptivity in the upper layer, which is the typical biological case in tissues like skin.

  7. 制冷用水平管降膜蒸发器管束换热特性数值模拟%Numerical Simulation of the Heat Transfer Performance of Horizontal Falling Film Evaporator in the Large Refrigeration Systems

    Institute of Scientific and Technical Information of China (English)

    杨培志; 张营; 李晓

    2015-01-01

    A theoretical thermodynamic model with distributed parameters was developed for simulating the falling film heat transfer performance,and in this model the effect of film breakdown (or dry patch)is considered.In this simulation ,the distribu-tion of dry patch,average falling film factor is obtained,and the effect of the tube bundle layout,refrigerant mass flow rate,tube pitch,the flooded tube row amount is also analyzed.This study is a contribution for the design of horizontal falling film evaporators and promote their application in the field of refrigeration and air conditioning.%采用分布参数法建立水平管降膜蒸发器管束换热模型,模拟计算了水平管降膜蒸发器不同管程布置下换热管干斑分布和平均降膜因子,并进行比较分析;并在下进上出的管程布置形式下研究了制冷剂流量、管间距、满液区排管数对蒸发器换热性能的影响。本文的研究为水平管降膜蒸发器的设计提供理论指导,促进其在制冷空调领域的推广应用。

  8. 倾斜降膜蒸发特性实验研究%Experimental Study on Evaporation Characteristics of Inclined Falling Film

    Institute of Scientific and Technical Information of China (English)

    倪明江; 王菲; 肖刚; 朱伟军; 王锡辉; 岑可法

    2013-01-01

    以电加热作为供热热源来模拟太阳能,研究了不同工况下倾斜降膜蒸发特性,通过对蒸馏器吸热面和冷凝面划分等间距小区段,根据液膜和冷凝面的温度分布,利用Dunkle模型预测了蒸馏器的产水速率.结果表明:热流密度、单位长度给水质量流量、倾斜角度和单位长度冷却水质量流量是影响蒸馏器产水速率的主要因素;产水速率随着热流密度的增大呈线性增加;在单位长度给水质量流量为5.5~10.0 kg/(h·m)时,产水速率随着单位长度给水质量流量的减小呈线性增大,单位长度给水质量流量为0.7~5.5 kg/(h·m)时,产水速率波动较小;在倾斜角度为15°~60°时,产水速率随着倾斜角度的增大而增大;冷却水均匀地流过冷凝面上表面有助于增大蒸馏器的产水速率;蒸馏器吸热面和冷凝面划分的区段越多,模型预测值与实验值吻合越好.%Evaporation characteristics of inclined falling film were studied under various working conditions by adopting electric heat instead of solar energy,while the still's distillate production rate predicted using Dunkle model based on temperature distribution of the liquid film and condensing surface by dividing both the heat-absorbing and the condensing surface into evenly-spaced segments.Results show that the heat flux density,feed water flow,inclination angle,and cooling water flow are the main factors affecting the distillate production rate,which increases linearly with the rise of heat flux density; when the feed water flow is within 5.5-10.0 kg/(h · m),the distillate production rate increases linearly with the decrease of feed water flow,whereas when the feed water flow is within 0.7-5.5 kg/(h · m),the distillate production rate basically remains unchanged; In the range of inclination angle varying from 15° to 60°,the distillate production rate increases as the inclination angle increases; The still's distillate production rate

  9. Determination of the velocity profile of mixture flow in a falling film evaporator with rating blades; Determinacao do perfil de velocidade no escoamento de uma mistura em um evaporador de pelicula cadente com pas rotativas

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Ricardo Reis; Silva, Maria Eugenia Vieira da; Carioca, Jose Oswaldo Beserra; Hiluy Filho, Joao Jose [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil)

    2004-07-01

    The Falling Film Evaporator (FFE) is an industrial equipment that processes high viscosity, high heating sensitive and polymerizing capacity compounds. This equipment can be used in processing Cashew Nut Shell Liquid (CNSL), in the distillation of Cardanol, which is a component used to produce additives. The FFE has a cylindrical form with rotating internal blades. In the gap between the blades and the internal cylinder surface, liquid CNSL flows by gravity after being injected on the top of the cylinder. The blades rotate touching the film, transferring turbulence at the interface and increasing the convective heat and mass transfer process. This paper presents the conservation equations of momentum in the CNSL falling film and the necessary boundary conditions to solve the problem. A numerical procedure was used to numerically solve these equations using a finite difference scheme. The results show the axial and radial velocity profiles, which are needed in the solutions of the temperature and the concentration problems. These results are useful in the optimization of the separation processes that uses a FFE, such as in the CNSL process. (author)

  10. Investigations of Two-Layer Earth Parameters at Low Voltage: Measurements and Calculations

    National Research Council Canada - National Science Library

    E. Ramdan; N. M. Nor; K. Ramar

    2009-01-01

    Problem statement: The two-layer soil model at low magnitude voltage is assumed to be accurate for the measurement and calculation of the earth resistance of a combined grid-multiple rods electrode...

  11. Heat and mass transfer of heated falling film under gas-liquid cross-flow condition%气液叉流下受热液膜的热质传递特性

    Institute of Scientific and Technical Information of China (English)

    蒋斌; 王子云; 付祥钊; 王勇

    2011-01-01

    采用VOF两相流模型研究了气液叉流条件下受热液膜热质传递特性,在模型中添加了表面张力源项和气液相间传质源项.为了验证所建立模型的可靠性,采用非接触式红外热成像测温方法,进行了相应的气液叉流试验.对叉流条件下受热液膜热质传递过程进行了试验和模拟计算,结果显示无量纲壁面温度计算结果与试验结果吻合很好.应用所建立的模型,模拟计算并分析了表面张力、固液接触角、液膜流量等因素对液膜流动侧形和热质传递性能的影响,结果表明:在其他参数保持不变的情况下,表面张力从0.014 N/m增大到0.072 N/m的过程中,液膜覆盖面积由82.7%减小到73.2%;固液接触角从30°增大到60°的过程中,液膜覆盖面积由80.6%减小到69.4%;液膜流量越小,液膜厚度越小,越有利于液膜的蒸发;相反,较高的液膜流量会使液膜厚度增大,阻碍了液膜蒸发,从而使外掠过液膜的单位体积空气含湿量减小.%Based on volume of fluid(VOF) method,heat and mass transfer of heated falling film under gas-liquid cross-flow condition was investigated. Surface tension and species transport were taken into account. In order to verify reliability of the model,the experiment was performed by non-contact infrared thermal imaging technology under gas-liquid cross-flow condition. Heat and mass transfer of heated falling film under gas-liquid cross-flow condition was investigated experimentally and theoretically. The results show that the simulated dimensionless wall temperature is in good agreement with the experimental data. Based on the model, the influence of surface tension coefficient, solid-liquid contact angle and liquid film flow rate on heat transfer of liquid film was simulated. It is found that, remaining constant of other parameters, liquid film interfacial area decreases from 82. 7% to 73. 2% in corresponding with surface tension coefficient increases

  12. Modeling a falling slinky

    CERN Document Server

    Cross, R C

    2012-01-01

    A slinky is an example of a tension spring: in an unstretched state a slinky is collapsed, with turns touching, and a finite tension is required to separate the turns from this state. If a slinky is suspended from its top and stretched under gravity and then released, the bottom of the slinky does not begin to fall until the top section of the slinky, which collapses turn by turn from the top, collides with the bottom. The total collapse time t_c (typically ~0.3 s for real slinkies) corresponds to the time required for a wave front to propagate down the slinky to communicate the release of the top end. We present a modification to an existing model for a falling tension spring (Calkin 1993) and apply it to data from filmed drops of two real slinkies. The modification of the model is the inclusion of a finite time for collapse of the turns of the slinky behind the collapse front propagating down the slinky during the fall. The new finite-collapse time model achieves a good qualitative fit to the observed posit...

  13. Modeling a falling slinky

    Science.gov (United States)

    Cross, R. C.; Wheatland, M. S.

    2012-12-01

    A slinky is an example of a tension spring: in an unstretched state a slinky is collapsed, with turns touching, and a finite tension is required to separate the turns from this state. If a slinky is suspended from its top and stretched under gravity and then released, the bottom of the slinky does not begin to fall until the top section of the slinky, which collapses turn by turn from the top, collides with the bottom. The total collapse time tc (typically ˜0.3 s for real slinkies) corresponds to the time required for a wave front to propagate down the slinky to communicate the release of the top end. We present a modification to an existing model for a falling tension spring [Calkin, Am. J. Phys. 61, 261-264 (1993)] and apply it to data from filmed drops of two real slinkies. The modification of the model is the inclusion of a finite time for collapse of the turns of the slinky behind the collapse front propagating down the slinky during the fall. The new finite-collapse time model achieves a good qualitative fit to the observed positions of the top of the real slinkies during the measured drops. The spring constant k for each slinky is taken to be a free parameter in the model. The best-fit model values for k for each slinky are approximately consistent with values obtained from measured periods of oscillation of the slinkies.

  14. LD苹果酸降膜蒸发器内流体的传热性能模拟%Simulation of heat transfer performance for falling-film evaporator of LD malic acid

    Institute of Scientific and Technical Information of China (English)

    朱永峰; 李庆生; 柳杰; 马勇

    2013-01-01

    采用降膜蒸发器对LD苹果酸溶液蒸发浓缩时,蒸发器的性能对产品质量有着重要的影响.采用湍流模型对蒸发器内流体的二维两相流场进行数值模拟,探讨物料初始温度和进料量对蒸发器传热性能的影响,结果表明:进料量对蒸发器的传热性能影响较大,而物料初始温度对蒸发器的传热性能影响较小,研究结果可为降膜蒸发器优化设计提供依据.%The performance of falling-film evaporator has important influence on the products,when it's used to evaporate and concentrate the solution of LD malic acid.The turbulence model was applied to simulate the 2-D two-phase flow in the evaporator,the influence of material initial temperature and feed rate on the evaporation heat transfer performance was also discussed,the result showed that feed rate had a great influence on the evaporation heat transfer performance,while material initial temperature had less influence on the evaporation heat transfer performance,which provided the basis for optimization design of falling-film evaporator.

  15. Process analysis of two-layered tube hydroforming with analytical and experimental verification

    Energy Technology Data Exchange (ETDEWEB)

    Seyedkashi, S. M. Hossein [The University of Birjand, Birjand (Iran, Islamic Republic of); Panahizadeh R, Valiollah [Shahid Rajaee Teacher Training University, Tehran (Iran, Islamic Republic of); Xu, Haibin; Kim, Sang Yun; Moon, Young Hoon [Pusan National University, Busan (Korea, Republic of)

    2013-01-15

    Two-layered tubular joints are suitable for special applications. Designing and manufacturing of two layered components require enough knowledge about the tube material behavior during the hydroforming process. In this paper, hydroforming of two-layered tubes is investigated analytically, and the results are verified experimentally. The aim of this study is to derive an analytical model which can be used in the process design. Fundamental equations are written for both of the outer and inner tubes, and the total forming pressure is obtained from these equations. Hydroforming experiments are carried out on two different combinations of materials for inner and outer tubes; case 1: copper/aluminum and case 2: carbon steel/stainless steel. It is observed that experimental results are in good agreement with the theoretical model obtained for estimation of forming pressure able to avoid wrinkling.

  16. Lie symmetry analysis and exact solutions of the quasigeostrophic two-layer problem

    Science.gov (United States)

    Bihlo, Alexander; Popovych, Roman O.

    2011-03-01

    The quasigeostrophic two-layer model is of superior interest in dynamic meteorology since it is one of the easiest ways to study baroclinic processes in geophysical fluid dynamics. The complete set of point symmetries of the two-layer equations is determined. An optimal set of one- and two-dimensional inequivalent subalgebras of the maximal Lie invariance algebra is constructed. On the basis of these subalgebras, we exhaustively carry out group-invariant reduction and compute various classes of exact solutions. Wherever possible, reference to the physical meaning of the exact solutions is given. In particular, the well-known baroclinic Rossby wave solutions in the two-layer model are rediscovered.

  17. On stratification, barotropic tides, and secular changes in surface tidal elevations: Two-layer analytical models

    CERN Document Server

    Wetzel, Alfredo N; Cerovecki, Ivana; Hendershott, Myrl C; Karsten, Richard H; Miller, Peter D

    2013-01-01

    In this study the influence of stratification on surface tidal elevations in a two-layer analytical model is examined. The model assumes linearized, non-rotating, shallow-water dynamics in one dimension with astronomical forcing and allows for arbitrary topography. Both large scale (barotropic) and small scale (baroclinic) components of the surface tidal elevation are shown to be affected by stratification. It is also shown that the topography and basin boundaries affect the sensitivity of the barotropic surface tide to stratification significantly. In a companion paper it is shown that the barotropic tide in two-layer numerical models run in realistic global domains differs from its value in one-layer numerical models by amounts qualitatively consistent with analytic predictions from this paper. The analytical model also roughly predicts the sensitivity to perturbations in stratification in the two-layer domain model. Taken together, this paper and the companion paper therefore provide a framework to underst...

  18. Wave scattering by undulating bed topography in a two-layer ocean

    Institute of Scientific and Technical Information of China (English)

    P. MAITI; B. N. MANDAL; U. BASU

    2009-01-01

    The problem of wave scattering by undulating bed topography in a two-layer ocean is investigated on the basis of linear theory. In a two-layer fluid with the upper layer having a free surface, there exist two modes of waves propagating at both the free surface of the upper layer and the interface between the two layers. Due to a wave train of a particular mode incident on an obstacle which is bottom-standing on the lower layer, reflected and transmitted waves of both modes are created by the obstacle. For small undulations on the bottom of the lower layer, a perturbation method is employed to obtain first-order reflection and transmission coefficients of both modes for incident wave trains of again both modes in terms of integrals involving the bed-shape function. For sinusoidal undulations, numerical results are presented graphically to illustrate the energy transfer between the waves of different modes by the undulating bed.

  19. THE WAVE-MAKING CHARACTERISTICS OF A MOVING BODY IN A TWO-LAYER FLUID

    Institute of Scientific and Technical Information of China (English)

    ZHU Wei

    2005-01-01

    The Wave-making characteristics of a moving body in a two-layer fluid with free surface is investigated numerically and experimentally. The numerical analysis is based on the modified layered boundary integral equation system. The wave characteristics on the free surface and interface generated by a moving sphere and an ellipsoid is numerically simulated in both finite depth and infinite depth of lower layer model. The numerical results of the sphere are compared with the analytical results for a dipole with the same velocity in a two-layer fluid of finite depth. The dependence of the wave systems and structures on the characteristic quantities is discussed. Three kinds of measurement techniques are used in model experiments on the internal waves generated by a sphere advancing in a two-layer fluid. The effects of the varying velocity and stratification on the wavelength, wave amplitudes and the maximum half angles of internal waves are analyzed qualitatively.

  20. Band splitting and relative spin alignment in two-layer systems

    CERN Document Server

    Ovchinnikov, A A

    2002-01-01

    It is shown that the single-particle spectra of the low Hubbard zone in the two-layer correlated 2D-systems sharply differ in the case of different relative alignment of the layers spin systems. The behavior of the two-layer splitting in the Bi sub 2 Sr sub 2 CaCu sub 2 O sub 8 sub + subdelta gives all reasons for the hypothesis on the possible rearrangement of the F sub z -> AF sub z alignment configuration, occurring simultaneously with the superconducting transition. The effects of the spin alignment on the magnetic excitations spectrum, as the way for studying the spin structure of the two-layer systems, are discussed by the example of homogenous solutions for the effective spin models

  1. Ultrasound evaluation of the cesarean scar: comparison between one- and two layer uterotomy closure

    DEFF Research Database (Denmark)

    Glavind, Julie; Madsen, Lene Duch; Uldbjerg, Niels

    Objectives: To compare the residual myometrial thickness and the size of the cesarean scar defect after one- and two layer uterotomy closure. Methods: From July 2010 a continuous two-layer uterotomy closure technique replaced a continuous one-layer technique after cesarean delivery...... at the Department of Obstetrics and Gynecology at Aarhus University Hospital. A total of 149 consecutively invited women (68 women with one-layer and 81 women with two-layer closure) had their cesarean scar examined with 2D transvaginal sonography (TVS) 6-16 months post partum. Inclusion criteria were non......-pregnant women with one previous elective cesarean, no post-partum uterine infection or uterine re-operation, and no type 1 diabetes. Scar defect width, depth, and residual myometrial thickness were measured on the sagittal plane, and scar defect length was measured on the transverse plane. Results: The median...

  2. Design of two-layer switching rule for stabilization of switched linear systems with mismatched switching

    Institute of Scientific and Technical Information of China (English)

    Dan MA

    2014-01-01

    A two-layer switching architecture and a two-layer switching rule for stabilization of switched linear control systems are proposed, under which the mismatched switching between switched systems and their candidate hybrid controllers can be allowed. In the low layer, a state-dependent switching rule with a dwell time constraint to exponentially stabilize switched linear systems is given;in the high layer, supervisory conditions on the mismatched switching frequency and the mismatched switching ratio are presented, under which the closed-loop switched system is still exponentially stable in case of the candidate controller switches delay with respect to the subsystems. Different from the traditional switching rule, the two-layer switching architecture and switching rule have robustness, which in some extend permit mismatched switching between switched subsystems and their candidate controllers.

  3. Random Boundary Simulation of Pumping Groundwater on Two-layer Soft Soil Structure with Porous Media

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Based on random theory,fluid dynamics,porous media and soil mechanics,the porosity and random characteristic of the two-layer soft soil in Wuhan region were studied in this paper.The random seepage coefficient on the two-layer soft soil was analyzed,and the seepage model and its random distribution function were given.The groundwater flow differential equations related to the two layer soft soil structure were also established.The evaluation procedure of effect boundary on the pumping water in deep foundation pit was put forward.Moreover,with an engineering example,the probability distribution on random boundary prediction for pumping water of foundation pit was computed.

  4. Lie symmetry analysis and exact solutions of the quasi-geostrophic two-layer problem

    CERN Document Server

    Bihlo, Alexander

    2010-01-01

    The quasi-geostrophic two-layer model is of superior interest in dynamic meteorology since it is one of the easiest ways to study baroclinic processes in geophysical fluid dynamics. The complete set of point symmetries of the two-layer equations is determined. An optimal set of one- and two-dimensional inequivalent subalgebras of the maximum Lie invariance algebra is constructed. On the basis of these subalgebras we exhaustively carry out group-invariant reduction and compute various classes of exact solutions. Where possible, reference to the physical meaning of the exact solutions is given.

  5. Free surface simulation of a two-layer fluid by boundary element method

    Directory of Open Access Journals (Sweden)

    Weoncheol Koo

    2010-09-01

    Full Text Available A two-layer fluid with free surface is simulated in the time domain by a two-dimensional potential-based Numerical Wave Tank (NWT. The developed NWT is based on the boundary element method and a leap-frog time integration scheme. A whole domain scheme including interaction terms between two layers is applied to solve the boundary integral equation. The time histories of surface elevations on both fluid layers in the respective wave modes are verified with analytic results. The amplitude ratios of upper to lower elevation for various density ratios and water depths are also compared.

  6. Fall Protection Introduction, #33462

    Energy Technology Data Exchange (ETDEWEB)

    Chochoms, Michael [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-23

    The proper use of fall prevention and fall protection controls can reduce the risk of deaths and injuries caused by falls. This course, Fall Protection Introduction (#33462), is designed as an introduction to various types of recognized fall prevention and fall protection systems at Los Alamos National Laboratory (LANL), including guardrail systems, safety net systems, fall restraint systems, and fall arrest systems. Special emphasis is given to the components, inspection, care, and storage of personal fall arrest systems (PFASs). This course also presents controls for falling object hazards and emergency planning considerations for persons who have fallen.

  7. A two-layered approach to recognize high-level human activities

    NARCIS (Netherlands)

    N. Hu; G. Englebienne; B. Kröse

    2014-01-01

    Automated human activity recognition is an essential task for Human Robot Interaction (HRI). A successful activity recognition system enables an assistant robot to provide precise services. In this paper, we present a two-layered approach that can recognize sub-level activities and high-level activi

  8. Novel procedure to compute a contact zone magnitude of vibrations of two-layered uncoupled plates

    Directory of Open Access Journals (Sweden)

    Awrejcewicz J.

    2005-01-01

    Full Text Available A novel iteration procedure for dynamical problems, where in each time step, a contacting plates' zone is improved, is proposed. Therefore, a zone and magnitude of a contact load are also improved. Investigations of boundary conditions' influence on externally driven vibrations of uncoupled two-layer plates, where for each of the layers, the Kirchhoff hypothesis holds, are carried out.

  9. Learning behavior and temporary minima of two-layer neural networks

    NARCIS (Netherlands)

    Annema, Anne J.; Hoen, Klaas; Hoen, Klaas; Wallinga, Hans

    1994-01-01

    This paper presents a mathematical analysis of the occurrence of temporary minima during training of a single-output, two-layer neural network, with learning according to the back-propagation algorithm. A new vector decomposition method is introduced, which simplifies the mathematical analysis of

  10. Bilateral telemanipulation With time delays: a two-layer approach combining passivity and transparency

    NARCIS (Netherlands)

    Franken, Michel; Stramigioli, Stefano; Misra, Sarthak; Secchi, Cristian; Macchelli, Alessandro

    2011-01-01

    In this paper, a two-layer approach is presented to guarantee the stable behavior of bilateral telemanipulation sys- tems in the presence of time-varying destabilizing factors such as hard contacts, relaxed user grasps, stiff control settings, and/or communication delays. The approach splits the con

  11. Coupling of Flexural and Longitudinal Damped Vibration in a Two-Layered Beam

    Directory of Open Access Journals (Sweden)

    F. Pourroy

    1998-01-01

    Full Text Available In dynamics, the effect of varying the constitutive materials’ thickness of a two-layered beam is investigated. Resonance frequencies and damping variations are determined. It is shown that for specific thicknesses the coupling of longitudinal and flexural vibrations influences the global modal damping ratio significantly.

  12. Evaluation Method and Experimental Performance of Inner Vertical Adiabatic Falling Film Absorption%管内垂直降膜绝热吸收评估方法与实验分析

    Institute of Scientific and Technical Information of China (English)

    林芃; 王如竹; 徐振中; 邵飞; 王吉

    2013-01-01

    The performance of NH3-H2O inner vertical adiabatic falling film absorption was studied based on the experimental set-up.The potential of absorption was just given by the inlet sub-cooling of the weak solution.Variable working conditions were performed and tested.A novel evaluation method related to Sherwood number was derived from the conservation and transfer equations,which was used to evaluate the experimental data.The experimental results show that transfer rates and Sherwood numbers increase with the growing of Reynolds numbers.The mass transfer process is enhanced by increasing absorption pressure or inlet sub-cooling.The mass transfer performance of coupled heat and mass transfer combined with inlet sub-cooling is higher than inlet sub-cooling or coupled heat and mass transfer only.Sherwood correlation has been fitted based on the experimental data to evaluate the adiabatic falling film absorption.It could be used in designing falling film absorber whose heat and mass transfer are independent of each other.%构建了氨水降膜吸收实验设备,研究垂直管内降膜绝热吸收性能.通过套管换热器调节稀溶液入口过冷度,给予溶液吸收潜力,进行变工况降膜吸收实验.基于传质微分方程推导一种新的舍伍德数计算方法,用于传质性能评估.实验表明,传质速率以及舍伍德数随着雷诺数的增大而增大.增加吸收压力,稀溶液入口过冷度均能强化传质效果.具有过冷度的耦合传热传质过程传质速率及舍伍德数大于单独的过冷绝热吸收或者耦合传热传质吸收.利用实验结果拟合绝热吸收传质舍伍德数方程,可应用于传热传质分离的降膜吸收器热设计.

  13. Single-layer versus two-layer stamps for reduced pressure thermal nanoimprint

    Science.gov (United States)

    Papenheim, Marc; Dhima, Khalid; Wang, Si; Steinberg, Christian; Scheer, Hella-Christin

    2015-11-01

    Low-pressure imprint is interesting to avoid stamp deformation, stamp failure as well as polymer recovery. When large-area stamps are prepared with a stepping procedure, low pressure is required to optimize the stitching. However, with low-pressure imprint, conformal contact between stamp and substrate is critical. Admittedly, the imprint pressure required for conformal contact depends on the stamp material and its thickness. To get an idea to which extent the imprint pressure can be reduced with a flexible stamp, we compared different stamp materials and stamp architectures, single-layer stamps and two-layer stamps. The two-layer stamps are replica stamps, where the structures were replicated in a thin layer of OrmoStamp, fixed by a backplane. On the background of plate theory, we deduce the pressure reduction compared to a Si stamp by calculating the respective pressure ratio, independent from geometries. In addition, temperature-induced issues are addressed which are of relevance for a thermal imprint process. These issues are related to the mismatch between the thermal expansion coefficients of the stamp and the substrate, and in case of a two-layer stamp, to the mismatch between the backplane material and the top layer. The latter results in temperature-induced stamp bending. On the basis of simple analytical calculations, the potential of single-layer stamps and two-layer stamps with respect to thermal imprint at reduced pressure is discussed and guidelines are provided to assess the imprint situation when replica stamps are used for imprint. The results demonstrate the attractiveness of two-layer stamps for reduced pressure nanoimprint, even in a temperature-based process.

  14. Separation and purification of dodecanedioic acid from its homologous compounds by falling film crystallization%应用降膜结晶法将十二烷二酸从同系物中分离及精制

    Institute of Scientific and Technical Information of China (English)

    李裕; 刘有智; 齐雪琴

    2004-01-01

    Separation and purification ofdodecanedioic acid(DDDA)from its homologous compounds were studied experimentally by falling film crystallization(FFC).The influences of various operation parameters,including crystallizing time,flow rate of melt and temperature of glycerine bath,on purity of DDDA and crystallizing rate were investigated.Over 99%(by mole)DDDA was obtained for a feed composition of 96%(by mole).The main factors affecting the separation efficiency are flow rate of melt and temperature of glycerine bath.The crystallizing layer of DDDA was further purified by sweating and blasting.A set of optimized operation data are provided for better understanding the mechanism of heat and mass transfer in FFC,and for further industrial application of DDDA purification process.

  15. 基于分布参数模型的水平管式降膜蒸发器模拟%Prediction of the Performance of Falling Film Evaporator with Horizontal Tube Bundle Based on a Distributed Parameter Model

    Institute of Scientific and Technical Information of China (English)

    翟玉燕; 黄兴华

    2009-01-01

    A distributed parameter model is developed for predicting the performance of a horizontal-tube falling-film evaporator. In this model, the variation of heat transfer performance along the tube length and array, as well as the effect of the dry patch on the performance are considered. The model is applied to predicting the performance of a commercial falling film evaporator, and the influences of bundle layout, pass layout, refrigerant mass flow rate and the flooded level of refrigerant on the evaporator performances are studied. The results show that the simulation result agrees well with the experimental data, and it is possible to decrease or avoid the dry patch area on the tube bundle and therefore improve the evaporator performance by rationallly designing the layout of the tube bundle and the flooded level of the refrigerant.%建立水平管式降膜蒸发器蒸发换热的分布参数模型,考虑换热性能沿管子轴向、管排方向的变化,以及传热管发生干斑现象时对降膜蒸发的影响.对一降膜蒸发器的性能进行模拟分析,并考察管束布置、制冷剂液膜质量流量、管程布置以及满液位置对降膜蒸发器性能的影响.结果表明,计算结果和试验结果吻合良好,通过合理的设计管排方式和满液位置,可以减少或避免干斑现象的发生,提高降膜蒸发器性能.

  16. Falls and Older Adults

    Science.gov (United States)

    ... version of this page please turn Javascript on. Falls and Older Adults About Falls Risk Increases With Age Many people have a ... problems -- rises with age. Click for more information Falls Lead to Fractures, Trauma Each year, more than ...

  17. Waves induced by a submerged moving dipole in a two-layer fluid of finite depth

    Institute of Scientific and Technical Information of China (English)

    Gang Wei; Dongqiang Lu; Shiqiang Dai

    2005-01-01

    The waves induced by a moving dipole in a twofluid system are analytically and experimentally investigated.The velocity potential of a dipole moving horizontally in the lower layer of a two-layer fluid with finite depth is derived by superposing Green's functions of sources (or sinks). The far-field waves are studied by using the method of stationary phase. The effects of two resulting modes, i.e. the surfaceand internal-wave modes, on both the surface divergence field and the interfacial elevation are analyzed. A laboratory study on the internal waves generated by a moving sphere in a two-layer fluid is conducted in a towing tank under the same conditions as in the theoretical approach. The qualitative consistency between the present theory and the laboratory study is examined and confirmed.

  18. Analysis of Two-Layered Random Interfaces for Two Dimensional Widom-Rowlinson's Model

    Directory of Open Access Journals (Sweden)

    Jun Wang

    2011-01-01

    Full Text Available The statistical behaviors of two-layered random-phase interfaces in two-dimensional Widom-Rowlinson's model are investigated. The phase interfaces separate two coexisting phases of the lattice Widom-Rowlinson model; when the chemical potential μ of the model is large enough, the convergence of the probability distributions which describe the fluctuations of the phase interfaces is studied. In this paper, the backbones of interfaces are introduced in the model, and the corresponding polymer chains and cluster expansions are developed and analyzed for the polymer weights. And the existence of the free energy for two-layered random-phase interfaces of the two-dimensional Widom-Rowlinson model is given.

  19. Nonlinear dynamics at the interface of two-layer stratified flows over pronounced obstacles

    CERN Document Server

    Cabeza, C; Bove, I; Freire, D; Marti, Arturo C; Sarasua, L G; Usera, G; Montagne, R; Araújo, M

    2008-01-01

    The flow of a two--layer stratified fluid over an abrupt topographic obstacle, simulating relevant situations in oceanographic problems, is investigated numerically and experimentally in a simplified two--dimensional situation. Experimental results and numerical simulations are presented at low Froude numbers in a two-layer stratified flow and for two abrupt obstacles, semi--cylindrical and prismatic. We find four different regimes of the flow immediately past the obstacles: sub-critical (I), internal hydraulic jump (II), Kelvin-Helmholtz at the interface (III) and shedding of billows (IV). The critical condition for delimiting the experiments is obtained using the hydraulic theory. Moreover, the dependence of the critical Froude number on the geometry of the obstacle are investigated. The transition from regime III to regime IV is explained with a theoretical stability analysis. The results from the stability analysis are confirmed with the DPIV measurements. In regime (IV), when the velocity upstream is lar...

  20. Nonstationary Axisymmetric Temperature Field in a Two-Layer Slab Under Mixed Heating Conditions

    Science.gov (United States)

    Turchin, I. N.; Timar, I.; Kolodii, Yu. A.

    2015-09-01

    With the use of the Laguerre and Hankel integral transforms, the solution of a two-dimensional initial-boundary-value heat conduction problem for a two-layer slab under mixed boundary conditions is constructed: one of the surfaces is heated by a heat flux distributed axisymmetrically in a circle of radius R and is cooled by the Newton law outside this circle. The solution of the problem is reduced to a sequence of infinite quasi-regular systems of algebraic equations. The results of numerical analysis of the temperature field in the two-layer slab made from an aluminum alloy and ceramicsare presented depending on the relative geometric properties of the components and cooling intensity.

  1. A Two-layer Model for the Simulation of the VARTM Process with Resin Distribution Layer

    Science.gov (United States)

    Young, Wen-Bin

    2013-12-01

    Vacuum assisted resin transfer molding (VARTM) is one of the important processes to fabricate high performance composites. In this process, resin is drawn into the mold to impregnate the fiber reinforcement to a form composite. A resin distribution layer with high permeability was often introduced on top of the fiber reinforcement to accelerate the filling speed. Due to the difference of the flow resistance in the resin distribution layer and the reinforcement as well as the resulting through thickness transverse flow, the filling flow field is intrinsically three-dimensional. This study developed a two-layer model with two-dimensional formulation to simulate the filling flow of the VARTM process with a resin distribution layer. Two-dimensional flow was considered in each layer and a transverse flow in the thickness direction was estimated between the two layers. Thermal analysis including the transverse convection was also performed to better simulate the temperature distribution.

  2. Estimation of apparent soil resistivity for two-layer soil structure

    Energy Technology Data Exchange (ETDEWEB)

    Nassereddine, M.; Rizk, J.; Nagrial, M.; Hellany, A. [School of Computing, Engineering and Mathematics, University of Western Sydney (Australia)

    2013-07-01

    High voltage (HV) earthing design is one of the key elements when it comes to safety compliance of a system. High voltage infrastructure exposes workers and people to unsafe conditions. The soil structure plays a vital role in determining the allowable and actual step/touch voltage. This paper presents vital information when working with two-layer soil structure. It shows the process as to when it is acceptable to use a single layer instead of a two-layer structure. It also discusses the simplification of the soil structure approach depending on the reflection coefficient. It introduces the reflection coefficient K interval which determines if single layer approach is acceptable. Multiple case studies are presented to address the new approach and its accuracy.

  3. TAILING WAVETRAIN GENERATION IN PRECURSOR SOLITON GENERATION IN TWO-LAYER FLOW

    Institute of Scientific and Technical Information of China (English)

    Xu Zhaoting; Xu Hao; Samuel Shan-pu Shen

    2000-01-01

    A theory of tailing wavetrain generation for the precursor soliton generation in two-layer flow is presented by using averaged KdV equations(AKdV),which are derived by the authors in terms of Whitham's method of averaging[1,2].From the AKdV equations,group velocities of the tailing wavetrain generation are obtained by means of generating conditions of the tailing wavetrains,furthermore an analytical solution of the tailing wavetrain generation is found theoretically.A comparison between the theoretical and numerical results is carried out in the present paper,which shows that the theoretical results are in good agreement with the numerical ones,obtained from the fKdV equation in two-layer flow with the depth of unity in the rest.

  4. Unidirectional light propagation through two-layer nanostructures based on optical near-field interactions

    CERN Document Server

    Naruse, Makoto; Ishii, Satoshi; Drezet, Aurélien; Huant, Serge; Hoga, Morihisa; Ohyagi, Yasuyuki; Matsumoto, Tsutomu; Tate, Naoya; Ohtsu, Motoichi

    2014-01-01

    We theoretically demonstrate direction-dependent polarization conversion efficiency, yielding unidirectional light transmission, through a two-layer nanostructure by using the angular spectrum representation of optical near-fields. The theory provides results that are consistent with electromagnetic numerical simulations. This study reveals that optical near-field interactions among nanostructured matter can provide unique optical properties, such as the unidirectionality observed here, and offers fundamental guiding principles for understanding and engineering nanostructures for realizing novel functionalities.

  5. Two-layer cold storage method for pancreas and islet cell transplantation

    Institute of Scientific and Technical Information of China (English)

    Yasuhiro; Fujino

    2010-01-01

    The two-layer cold storage method (TLM) was f irst reported in 1988, consisting of a perfluorochemical (PFC) and initially Euro-Collins' solution, which was later replaced by University of Wisconsin solution (UW). PFC is a biologically inert liquid and acts as an oxygen-supplying agent. A pancreas preserved using the TLM is oxygenated through the PFC and substrates are supplied by the UW solution. This allows the pancreas preserved using the TLM to generate adenosine triphosphate during storage, prolonging ...

  6. SH-TM mathematical analogy for the two-layer case. A magnetotellurics application

    OpenAIRE

    J. Carcione; F. Poletto

    2017-01-01

    The same mathematical formalism of the wave equation can be used to describe anelastic and electromagnetic wave propagation. In this work, we obtain the mathematical analogy for the reflection/refraction (transmission) problem of two layers, considering the presence of anisotropy and attenuation -- viscosity in the viscoelastic case and resistivity in the electromagnetic case. The analogy is illustrated for SH (shear-horizontally polarised) and TM (transverse-magnetic) waves. In particular, w...

  7. On Theory of Dispersive Transport in a Two-Layer Polymer Structure

    Science.gov (United States)

    Sibatov, R. T.; Morozova, E. V.

    2016-09-01

    Dispersive transport of charge carriers in a two-layer polymer structure is modeled on the basis of the integrodifferential equation of hereditary diffusion. The model of multiple trapping in a bilayer is generalized to the case of an arbitrary density of localized states. With the help of an efficient Monte Carlo algorithm, curves of the transient current are calculated and their features are explained within the framework of a stochastic interpretation of the process.

  8. On two-layer models and the similarity functions for the PBL

    Science.gov (United States)

    Brown, R. A.

    1982-01-01

    An operational Planetary Boundary Layer model which employs similarity principles and two-layer patching to provide state-of-the-art parameterization for the PBL flow is used to study the popularly used similarity functions, A and B. The expected trends with stratification are shown. The effects of baroclinicity, secondary flow, humidity, latitude, surface roughness variation and choice of characteristic height scale are discussed.

  9. Two-layer cold storage method for pancreas and islet cell transplantation

    OpenAIRE

    Fujino, Yasuhiro

    2010-01-01

    The two-layer cold storage method (TLM) was first reported in 1988, consisting of a perfluorochemical (PFC) and initially Euro-Collins’ solution, which was later replaced by University of Wisconsin solution (UW). PFC is a biologically inert liquid and acts as an oxygen-supplying agent. A pancreas preserved using the TLM is oxygenated through the PFC and substrates are supplied by the UW solution. This allows the pancreas preserved using the TLM to generate adenosine triphosphate during storag...

  10. A Two Layer Approach to the Computability and Complexity of Real Functions

    DEFF Research Database (Denmark)

    Lambov, Branimir Zdravkov

    2003-01-01

    We present a new model for computability and complexity of real functions together with an implementation that it based on it. The model uses a two-layer approach in which low-type basic objects perform the computation of a real function, but, whenever needed, can be complemented with higher type...... in computable analysis, while the efficiency of the implementation is not compromised by the need to create and maintain higher-type objects....

  11. Phase transitions and kinetic properties of gold nanoparticles confined between two-layer graphene nanosheets

    Science.gov (United States)

    Wang, Gang; Wu, Nanhua; Chen, Jionghua; Wang, Jinjian; Shao, Jingling; Zhu, Xiaolei; Lu, Xiaohua; Guo, Lucun

    2016-11-01

    The thermodynamic and kinetic behaviors of gold nanoparticles confined between two-layer graphene nanosheets (two-layer-GNSs) are examined and investigated during heating and cooling processes via molecular dynamics (MD) simulation technique. An EAM potential is applied to represent the gold-gold interactions while a Lennard-Jones (L-J) potential is used to describe the gold-GNS interactions. The MD melting temperature of 1345 K for bulk gold is close to the experimental value (1337 K), confirming that the EAM potential used to describe gold-gold interactions is reliable. On the other hand, the melting temperatures of gold clusters supported on graphite bilayer are corrected to the corresponding experimental values by adjusting the εAu-C value. Therefore, the subsequent results from current work are reliable. The gold nanoparticles confined within two-layer GNSs exhibit face center cubic structures, which is similar to those of free gold clusters and bulk gold. The melting points, heats of fusion, and heat capacities of the confined gold nanoparticles are predicted based on the plots of total energies against temperature. The density distribution perpendicular to GNS suggests that the freezing of confined gold nanoparticles starts from outermost layers. The confined gold clusters exhibit layering phenomenon even in liquid state. The transition of order-disorder in each layer is an essential characteristic in structure for the freezing phase transition of the confined gold clusters. Additionally, some vital kinetic data are obtained in terms of classical nucleation theory.

  12. Long-term persistence of oil from the Exxon Valdez spill in two-layer beaches

    Science.gov (United States)

    Li, Hailong; Boufadel, Michel C.

    2010-02-01

    Oil spilled from the tanker Exxon Valdez in 1989 (refs 1, 2) persists in the subsurface of gravel beaches in Prince William Sound, Alaska. The contamination includes considerable amounts of chemicals that are harmful to the local fauna. However, remediation of the beaches was stopped in 1992, because it was assumed that the disappearance rate of oil was large enough to ensure a complete removal of oil within a few years. Here we present field data and numerical simulations of a two-layered beach with a small freshwater recharge in the contaminated area, where a high-permeability upper layer is underlain by a low-permeability lower layer. We find that the upper layer temporarily stored the oil, while it slowly and continuously filled the lower layer wherever the water table dropped below the interface of the two layers, as a result of low freshwater recharge from the land. Once the oil entered the lower layer, it became entrapped by capillary forces and persisted there in nearly anoxic conditions that are a result of the tidal hydraulics in the two-layered beaches. We suggest that similar dynamics could operate on tidal gravel beaches around the world, which are particularly common in mid- and high-latitude regions, with implications for locating spilled oil and for its biological remediation.

  13. Steady internal waves in an exponentially stratified two-layer fluid

    Science.gov (United States)

    Makarenko, Nikolay; Maltseva, Janna; Ivanova, Kseniya

    2016-04-01

    The problem on internal waves in a weakly stratified two-layered fluid is studied analytically. We suppose that the fluid possess exponential stratification in both the layers, and the fluid density has discontinuity jump at the interface. By that, we take into account the influence of weak continuous stratification outside of sharp pycnocline. The model equation of strongly nonlinear interfacial waves propagating along the pycnocline is considered. This equation extends approximate models [1-3] suggested for a two-layer fluid with one homogeneous layer. The derivation method uses asymptotic analysis of fully nonlinear Euler equations. The perturbation scheme involves the long wave procedure with a pair of the Boussinesq parameters. First of these parameters characterizes small density slope outside of pycnocline and the second one defines small density jump at the interface. Parametric range of solitary wave solutions is characterized, including extreme regimes such as plateau-shape solitary waves. This work was supported by RFBR (grant No 15-01-03942). References [1] N. Makarenko, J. Maltseva. Asymptotic models of internal stationary waves, J. Appl. Mech. Techn. Phys, 2008, 49(4), 646-654. [2] N. Makarenko, J. Maltseva. Phase velocity spectrum of internal waves in a weakly-stratified two-layer fluid, Fluid Dynamics, 2009, 44(2), 278-294. [3] N. Makarenko, J. Maltseva. An analytical model of large amplitude internal solitary waves, Extreme Ocean Waves, 2nd ed. Springer 2015, E.Pelinovsky and C.Kharif (Eds), 191-201.

  14. A two-layer flow model to represent ice-ocean interactions beneath Antarctic ice shelves

    Science.gov (United States)

    Lee, V.; Payne, A. J.; Gregory, J. M.

    2011-01-01

    We develop a two-dimensional two-layer flow model that can calculate melt rates beneath ice shelves from ocean temperature and salinity fields at the shelf front. The cavity motion is split into two layers where the upper plume layer represents buoyant meltwater-rich water rising along the underside of the ice to the shelf front, while the lower layer represents the ambient water connected to the open ocean circulating beneath the plume. Conservation of momentum has been reduced to a frictional geostrophic balance, which when linearized provides algebraic equations for the plume velocity. The turbulent exchange of heat and salt between the two layers is modelled through an entrainment rate which is directed into the faster flowing layer. The numerical model is tested using an idealized geometry based on the dimensions of Pine Island Ice Shelf. We find that the spatial distribution of melt rates is fairly robust. The rates are at least 2.5 times higher than the mean in fast flowing regions corresponding to the steepest section of the underside of the ice shelf close to the grounding line and to the converged geostrophic flow along the rigid lateral boundary. Precise values depend on a combination of entrainment and plume drag coefficients. The flow of the ambient is slow and the spread of ocean scalar properties is dominated by diffusion.

  15. A two-layer flow model to represent ice-ocean interactions beneath Antarctic ice shelves

    Directory of Open Access Journals (Sweden)

    V. Lee

    2011-01-01

    Full Text Available We develop a two-dimensional two-layer flow model that can calculate melt rates beneath ice shelves from ocean temperature and salinity fields at the shelf front. The cavity motion is split into two layers where the upper plume layer represents buoyant meltwater-rich water rising along the underside of the ice to the shelf front, while the lower layer represents the ambient water connected to the open ocean circulating beneath the plume. Conservation of momentum has been reduced to a frictional geostrophic balance, which when linearized provides algebraic equations for the plume velocity. The turbulent exchange of heat and salt between the two layers is modelled through an entrainment rate which is directed into the faster flowing layer.

    The numerical model is tested using an idealized geometry based on the dimensions of Pine Island Ice Shelf. We find that the spatial distribution of melt rates is fairly robust. The rates are at least 2.5 times higher than the mean in fast flowing regions corresponding to the steepest section of the underside of the ice shelf close to the grounding line and to the converged geostrophic flow along the rigid lateral boundary. Precise values depend on a combination of entrainment and plume drag coefficients. The flow of the ambient is slow and the spread of ocean scalar properties is dominated by diffusion.

  16. A two-layer optimization model for high-speed railway line planning

    Institute of Scientific and Technical Information of China (English)

    Li WANG; Li-min JIA; Yong QIN; Jie XU; Wen-ring MO

    2011-01-01

    Line planning is the first important strategic element in the railway operation planning process,which will directly affect the successive planning to determine the efficiency of the whole railway system.A two-layer optimization model is proposed within a simulation framework to deal with the high-speed railway (HSR) line planning problem.In the model,the top layer aims at achieving an optimal stop-schedule set with the service frequencies,and is formulated as a nonlinear program,solved by genetic algorithm.The objective of top layer is to minimize the total operation cost and unserved passenger volume.Given a specific stop-schedule,the bottom layer focuses on weighted passenger flow assignment,formulated as a mixed integer program with the objective of maximizing the served passenger volume and minimizing the total travel time for all passengers.The case study on Taiwan HSR shows that the proposed two-layer model is better than the existing techniques.In addition,this model is also illustrated with the Beijing-Shanghai HSR in China.The result shows that the two-layer optimization model can reduce computation complexity and that an optimal set of stop-schedules can always be generated with less calculation time.

  17. Diffraction of Water Waves by A Vertically Floating Cylinder in A Two-Layer Fluid

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this paper, the diffraction of water waves by a vertically floating cylinder in a two-layer luid of a finite depth is studied. Analytical expressions for the hydrodynamic loads on the vertically floating cylinder are obtained by use of the method of eigenfunction expansions. The hydrodynamic loads on the vertically floating cylinder in a two-layer fluid include not only the surge, heave and pitch exciting forces due to the incident wave of the surface-wave mode, but also those due to the incident wave of the internal-wave mode. This is different from the case of a homogenous fluid. Some given examples show that, for a two-layer fluid system with a small density difference, the hydrodynamic loads for the surface-wave mode do not differ significantly from those due to surface waves in a single-layer fluid, but the hydrodynamic loads for the internal-wave mode are important over a wide range of frequencies. Moreover, also considered are the free surface and interface elevations generated by the diffraction wave due to the incident wave of the surface-wave and internal-wave modes, and transfer of energy between modes.

  18. Experimental results of 2-propanol dehydrogenation with a falling-liquid film reactor for solar chemical heat pump; Solar chemical heat pump ni okeru ryuka ekimakushiki 2-propanol bunkai hanno jikken

    Energy Technology Data Exchange (ETDEWEB)

    Doi, T.; Tanaka, T.; Ando, Y.; Takashima, T. [Electrotechnical Laboratory, Tsukuba (Japan); Koike, M.; Kamoshida, J. [Shibaura Institute of Technology, Tokyo (Japan)

    1997-11-25

    A solar chemical heat pump is intended to attempt multi-purposed effective utilization of solar energy by raising low temperature solar heat of about 100 degC to 150 to 200 degC by utilizing chemical reactions. The chemical heat pump under the present study uses a 2-propanol (IPA)/acetone/hydrogen system which can utilize low-temperature solar heat and has large temperature rising degree. It was found from the result of experiments and analyses that IPA dehydrogenation reaction can improve more largely the heat utilization rate in using a falling-liquid film reactor than using a liquid phase suspended system. As an attempt to improve further the heat utilization rate, this paper reports the result of experimental discussions on inclination angles of a reaction vessel and feed liquid flow rate which would affect the fluid condition of the liquid film. As a result of the experiments, the initial deterioration in the catalyst has settled in about 15 hours, and its activity has decreased to about 60% of the initial activity. It was made clear that the influence of the inclination angle of the reaction vessel on the reaction is small. 5 refs., 7 figs.

  19. FINITE ELEMENT FOR STRESS-STRAIN STATE MODELING OF TWO-LAYERED AXIALLY SYMMETRIC SHELLS

    Directory of Open Access Journals (Sweden)

    K. S. Kurochka

    2015-07-01

    Full Text Available Subject of Research. Computation of composite material designs requires application of numerical methods. The finiteelement method usage is connected with surface approximation problems. Application of volumetric and laminar elements leads to systems with large sizes and a great amount of computation. The objective of this paper is to present an equivalent two-layer mathematical model for evaluation of displacements and stresses of cross-ply laminated cone shells subjected to uniformly distributed load. An axially symmetric element for shell problems is described. Method. Axially symmetric finite element is proposed to be applied in calculations with use of correlation for the inner work of each layer separately. It gives the possibility to take into account geometric and physical nonlinearities and non-uniformity in the layers of the shell. Discrete mathematical model is created on the base of the finite-element method with the use of possible motions principle and Kirchhoff–Love assumptions. Hermite element is chosen as a finite one. Cone shell deflection is considered as the quantity sought for. Main Results. One-layered and two-layered cone shells have been considered for proposed mathematical model verification with known analytical and numerical analytical solutions, respectively. The axial displacements of the two-layered cone are measured with an error not exceeding 5.4 % for the number of finite elements equal to 30. The proposed mathematical model requires fewer nodes to define the finite element meshing of the system and much less computation time. Thereby time for finding solution decreases considerably. Practical Relevance. Proposed model is applicable for computation of multilayered designs under axially symmetric loads: composite high-pressure bottles, cylinder shaped fiberglass pipes, reservoirs for explosives and flammable materials, oil and gas storage tanks.

  20. PECULIARITIES OF LAMB WAVE PROPAGATION THROUGH TWO-LAYERED THIN PLATE MATERIALS

    Directory of Open Access Journals (Sweden)

    A. R. Baev

    2008-01-01

    Full Text Available Peculiarities of the plate wave propagation through two-layered thin plate have been analyzed and formulas for velocity determination of the quickest plate mode have been proposed.  The ascertained interaction makes it possible   to determine coating layer thickness in accordance with the given and known elastic parameters of contacting materials. On the basis of the developed methodology experiments have been carried out that revealed qualitative and quantitative correspondence  between theoretical and experimental data. The paper shows a principle possibility for assessment  of  material separation surface by time propagation data of the investigated mode .

  1. Determination of homeostatic elastic moduli in two layers of the esophagus

    DEFF Research Database (Denmark)

    Gregersen, Hans; Liao, Donghua; Fung, Yuan Cheng

    2008-01-01

    for determination of incremental moduli in circumferential, axial, and cross directions in the two layers. The experiments are inflation, axial stretching, circumferential bending, and axial bending. The analysis takes advantage of knowing the esophageal zero-stress state (an open sector with an opening angle of 59......The function of the esophagus is mechanical. To understand the function, it is necessary to know how the stress and strain in the esophagus can be computed, and how to determine the stress-strain relationship of the wall materials. The present article is devoted to the issue of determining...

  2. A novel two-layer compact electromagnetic bandgap (EBG) structure and its applications in microwave circuits

    Institute of Scientific and Technical Information of China (English)

    YANG; Ning(杨宁); CHEN; Zhining; (陈志宁); WANG; Yunyi; (王蕴仪); Chia; M.; Y.; W.

    2003-01-01

    This paper presents a novel two-layer electromagnetic bandgap (EBG) structure. The studies on the characteristics of the cell are carried out numerically and experimentally. A lumped-LC equivalent circuit extracted from the numerical simulation is used to model the bandgap characteristics of the proposed EBG structure. The influences of geometric parameters on the operation frequency and equivalent LC parameters are discussed. A meander line high performance bandstop filter and a notch type duplexer are designed and measured. These EBG structures are shown to have potential applications in microwave and RF systems.

  3. A Two-Layered Model for Dynamic Supply Chain Management Considering Transportation Constraint

    Science.gov (United States)

    Tanimizu, Yoshitaka; Harada, Kana; Ozawa, Chisato; Iwamura, Koji; Sugimura, Nobuhiro

    This research proposes a two-layered model for dynamic supply chain management considering transportation constraint. The model provides a method for suppliers to estimate suitable prices and delivery times of products based on not only production schedules but also transportation plans in consideration of constraints about shipping times and loading capacities for transportation. A prototype of dynamic supply chain simulation system was developed and some computational experiments were carried out in order to verify the effectiveness of the model. The prototype system is available to determine suitable shipping times and loading capacities of transportation vehicles.

  4. Flows induced by sorption on fibrous material in a two-layer oil-water system

    Science.gov (United States)

    Chaplina, T. O.; Chashechkin, Yu. D.; Stepanova, E. V.

    2016-09-01

    The processes of sorption on fibrous materials in the open elliptic cell filled with a two-layer oil-water liquid at rest are investigated experimentally. When the sorption efficiency dependent on the type of material proves to be reasonably high, large-scale flows are formed in the liquid. In this case, the uniformity of distribution of oil is violated and the free surface of the water is partially restored. The trajectories of motion of individual oil droplets on a released water surface are tracked, and the transfer rates are calculated in various phases of the process.

  5. SH-TM mathematical analogy for the two-layer case. A magnetotellurics application

    Directory of Open Access Journals (Sweden)

    J. Carcione

    2017-02-01

    Full Text Available The same mathematical formalism of the wave equation can be used to describe anelastic and electromagnetic wave propagation. In this work, we obtain the mathematical analogy for the reflection/refraction (transmission problem of two layers, considering the presence of anisotropy and attenuation -- viscosity in the viscoelastic case and resistivity in the electromagnetic case. The analogy is illustrated for SH (shear-horizontally polarised and TM (transverse-magnetic waves. In particular, we illustrate examples related to the magnetotelluric method applied to geothermal systems and consider the effects of anisotropy. The solution is tested with the classical solution for stratified isotropic media.

  6. Solitary SH waves in two-layered traction-free plates

    Science.gov (United States)

    Djeran-Maigre, Irini; Kuznetsov, Sergey

    2008-01-01

    A solitary wave, resembling a soliton wave, is observed when analyzing the linear problem of polarized shear (SH) surface acoustic waves propagating in elastic orthotropic two-layered traction-free plates. The analysis is performed by applying a special complex formalism and the Modified Transfer Matrix (MTM) method. Conditions for the existence of solitary SH waves are obtained. Analytical expressions for the phase speed of the solitary wave are derived. To cite this article: I. Djeran-Maigre, S. Kuznetsov, C. R. Mecanique 336 (2008).

  7. 螺旋槽管降膜蒸发强化传热与结垢特性研究%Enhanced Heat Transfer and Fouling Performance of the Spirally Fluted Tube in Falling Film Evaporation

    Institute of Scientific and Technical Information of China (English)

    邢玉雷; 齐春华; 韩旭; 冯厚军; 吕庆春; 冯建民

    2013-01-01

    降膜蒸发是海水淡化的一项主要技术.传热管是降膜蒸发器的核心部件.螺旋槽管是一种应用广泛的高效强化传热管,但在海水淡化中应用较少,缺乏相关的实验数据.为论证螺旋槽管用于海水淡化的可行性,首先在水平管降膜蒸发传热实验平台上,以自来水为工质,研究了螺旋槽管的强化传热特性,分析了喷淋密度、热通量、传热温差和蒸发温度对其传热的影响;然后借助低温多效蒸馏(LT-MED)海水淡化中试装置,在海水淡化实际工况下,运行测试180 d,研究了螺旋槽管的结垢特性.在本实验中,螺旋槽管传热系数较光管平均提高35%左右;其结垢厚度小于光管,结垢疏松多孔,易于清除.%Falling film evaporation is one main technique of seawater desalination.Heat transfer tube is core component of falling film evaporator.Spirally fluted tube is one of the widely used enhanced heat transfer tubes with high efficiency.However,there are few practical applications of the spirally fluted tube to seawater desalination.In order to evaluate the feasibility of its application to desalination,the enhanced heat transfer performance of the aluminum brass spirally fluted tube was investigated firstly,relying on the horizontal tube falling film evaporation heat transfer platform with the tap water as medium.The effect of sprinkling density,heat flux,temperature difference and evaporating temperature on heat transfer of the tube was analyzed.Then,the fouling performance of the spirally fluted tube was researched by means of a pilot plant of low temperature multiple effect distillation (LT-MED) desalination which was running 180 days in the actual working conditions of desalination projects.The results show that heat transfer efficiency of spirally fluted tube is 35% higher than that of smooth tube,and the fouling on the spirally fluted tube is thinner,more porous and easier to remove than that on the smooth tube.

  8. 润滑油对水平强化管降膜蒸发传热特性的影响%Effect of Lubricating Oil on Heat Transfer Performance of Falling Film Evaporation on Horizontal Enhanced Tube

    Institute of Scientific and Technical Information of China (English)

    李敏霞; 蔡文生; 孙晗; 党超镔; 吕佳桐

    2015-01-01

    实际制冷系统中的制冷剂含有压缩机的润滑油.本文研究了制冷剂中润滑油不同含油率时水平管降膜式蒸发传热特性.工质为R134a,含油率分别为0.5%、1.2%、5.1%,蒸发温度为6,℃,热流密度范围为30~65,kW/m2,工质喷淋密度分别为0.13,kg/(s·m),0.17,kg/(s·m)、0.21 kg/(s·m),测试段采用表面强化的铜管.实验结果表明:含油率从0.5%增大到5.1%,管外传热性能逐渐提高,当喷淋密度增加,管外换热系数也会提高,但随着含油率的增加,换热系数的增加幅度不大;一定含量的润滑油能增大R134a水平管降膜蒸发的换热系数.%In engineering practice,refrigerant contains lubricating oil form compressor in the refrigerating system. In this study,the impact of different oil contents on evaporation of falling film on horizontal enhanced tube was dis-cussed. Experiments were conducted for R134a at the saturation temperature of 6,℃ on enhanced copper tube,with oil contents being 0.5%,1.2% and 5.1%,respectively,and heat fluxes ranging from 30,kW/m2 to 65,kW/m2, sprinkle densities being 0.13,0.17,and 0.21,kg/(s·m). The experimental results show that heat transfer coefficient of the outside horizontal enhanced tube increases with both oil contents growing from 0.5% to 5.1% and increasing sprinkle densities. However,with the augments of oil contents,the increases of heat transfer coefficient are nearly insensitive to the increasing sprinkle densities. In certain range of content,lubricating oil can improve heat transfer coefficient of R134a falling film evaporation.

  9. Theories of multiple equilibria and weather regimes : A critical reexamination. II - Baroclinic two-layer models

    Science.gov (United States)

    Cehelsky, Priscilla; Tung, Ka Kit

    1987-01-01

    Previous results based on low- and intermediate-order truncations of the two-layer model suggest the existence of multiple equilibria and/or multiple weather regimes for the extratropical large-scale flow. The importance of the transient waves in the synoptic scales in organizing the large-scale flow and in the maintenance of weather regimes was emphasized. The result shows that multiple equilibria/weather regimes that are present in lower-order models examined disappear when a sufficient number of modes are kept in the spectral expansion of the solution to the governing partial differential equations. Much of the chaotic behavior of the large-scale flow that is present in intermediate-order models is now found to be spurious. Physical reasons for the drastic modification are offered. A peculiarity in the formulation of most existing two-layer models is noted that also tends to exaggerate the importance of baroclinic processes and increase the degree of unpredictability of the large-scale flow.

  10. Photoacoustic investigation of the effective diffusivity of two-layer semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Medina, J; Gurevich, Yu. G; Logvinov G, N; Rodriguez, P; Gonzalez de la Cruz, G. [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico)

    2001-08-01

    In this work, the problem of the effective thermal diffusivity of two-layer systems is investigated using the photoacoustic spectroscopy. The experimental results are examined in terms of the effective thermal parameters of the composite system determined from an homogeneous material which produces the same physical response under an external perturbation in the detector device. It is shown, that the effective thermal conductivity is not symmetric under exchange of the two layers of the composite; i.e., the effective thermal parameters depend upon which layer is illuminated in the photoacoustic experiments. Particular emphasis is given to the characterization of the interface thermal conductivity between the layer-system. [Spanish] En el presente trabajo se utiliza la espectroscopia fotoacustica para medir la difusividad termica de un sistema de dos capas. Los resultados experimentales son analizados en terminos de los parametros termicos efectivos determinados a partir de un material homogeneo, el cual produce la misma respuesta fisica bajo una perturbacion externa. Se puso particular enfasis en la caracterizacion de los efectos de interfase en el flujo de calor en el sistema de dos capas. Los resultados experimentales se comparan con el modelo teorico propuesto en este trabajo.

  11. Modelling of fast jet formation under explosion collision of two-layer alumina/copper tubes

    Directory of Open Access Journals (Sweden)

    I Balagansky

    2017-09-01

    Full Text Available Under explosion collapse of two-layer tubes with an outer layer of high-modulus ceramics and an inner layer of copper, formation of a fast and dense copper jet is plausible. We have performed a numerical simulation of the explosion collapse of a two-layer alumina/copper tube using ANSYS AUTODYN software. The simulation was performed in a 2D-axis symmetry posting on an Eulerian mesh of 3900x1200 cells. The simulation results indicate two separate stages of the tube collapse process: the nonstationary and the stationary stage. At the initial stage, a non-stationary fragmented jet is moving with the velocity of leading elements up to 30 km/s. The collapse velocity of the tube to the symmetry axis is about 2 km/s, and the pressure in the contact zone exceeds 700 GPa. During the stationary stage, a dense jet is forming with the velocity of 20 km/s. Temperature of the dense jet is about 2000 K, jet failure occurs when the value of effective plastic deformation reaches 30.

  12. Validation of the Two-Layer Model for Correcting Clear Sky Reflectance Near Clouds

    Science.gov (United States)

    Wen, Guoyong; Marshak, Alexander; Evans, K. Frank; Vamal, Tamas

    2014-01-01

    A two-layer model was developed in our earlier studies to estimate the clear sky reflectance enhancement near clouds. This simple model accounts for the radiative interaction between boundary layer clouds and molecular layer above, the major contribution to the reflectance enhancement near clouds for short wavelengths. We use LES/SHDOM simulated 3D radiation fields to valid the two-layer model for reflectance enhancement at 0.47 micrometer. We find: (a) The simple model captures the viewing angle dependence of the reflectance enhancement near cloud, suggesting the physics of this model is correct; and (b) The magnitude of the 2-layer modeled enhancement agree reasonably well with the "truth" with some expected underestimation. We further extend our model to include cloud-surface interaction using the Poisson model for broken clouds. We found that including cloud-surface interaction improves the correction, though it can introduced some over corrections for large cloud albedo, large cloud optical depth, large cloud fraction, large cloud aspect ratio. This over correction can be reduced by excluding scenes (10 km x 10km) with large cloud fraction for which the Poisson model is not designed for. Further research is underway to account for the contribution of cloud-aerosol radiative interaction to the enhancement.

  13. Risks of an epidemic in a two-layered railway-local area traveling network

    Science.gov (United States)

    Ruan, Zhongyuan; Hui, Pakming; Lin, Haiqing; Liu, Zonghua

    2013-01-01

    In view of the huge investments into the construction of high speed rails systems in USA, Japan, and China, we present a two-layer traveling network model to study the risks that the railway network poses in case of an epidemic outbreak. The model consists of two layers with one layer representing the railway network and the other representing the local-area transportation subnetworks. To reveal the underlying mechanism, we also study a simplified model that focuses on how a major railway affects an epidemic. We assume that the individuals, when they travel, take on the shortest path to the destination and become non-travelers upon arrival. When an infection process co-evolves with the traveling dynamics, the railway serves to gather a crowd, transmit the disease, and spread infected agents to local area subnetworks. The railway leads to a faster initial increase in infected agents and a higher steady state infection, and thus poses risks; and frequent traveling leads to a more severe infection. These features revealed in simulations are in agreement with analytic results of a simplified version of the model.

  14. Traffic dynamics on two-layer complex networks with limited delivering capacity

    Science.gov (United States)

    Ma, Jinlong; Han, Weizhan; Guo, Qing; Wang, Zhenyong

    2016-08-01

    The traffic dynamics of multi-layer networks has attracted a great deal of interest since many real networks are comprised of two or more layers of subnetworks. Due to its low traffic capacity, the average delivery capacity allocation strategy is susceptible to congestion with the wildly used shortest path routing protocol on two-layer complex networks. In this paper, we introduce a delivery capacity allocation strategy into the traffic dynamics on two-layer complex networks and focus on its effect on the traffic capacity measured by the critical point Rc of phase transition from free flow to congestion. When the total nodes delivering capacity is fixed, the delivering capacity of each node in physical layer is assigned to the degree distributions of both the physical and logical layers. Simulation results show that the proposed strategy can bring much better traffic capacity than that with the average delivery capacity allocation strategy. Because of the significantly improved traffic performance, this work may be useful for optimal design of networked traffic dynamics.

  15. Numerical simulation and analysis of complex patterns in a two-layer coupled reaction diffusion system

    Institute of Scientific and Technical Information of China (English)

    李新政; 白占国; 李燕; 贺亚峰; 赵昆

    2015-01-01

    The resonance interaction between two modes is investigated using a two-layer coupled Brusselator model. When two different wavelength modes satisfy resonance conditions, new modes will appear, and a variety of superlattice patterns can be obtained in a short wavelength mode subsystem. We find that even though the wavenumbers of two Turing modes are fixed, the parameter changes have infl uences on wave intensity and pattern selection. When a hexagon pattern occurs in the short wavelength mode layer and a stripe pattern appears in the long wavelength mode layer, the Hopf instability may happen in a nonlinearly coupled model, and twinkling-eye hexagon and travelling hexagon patterns will be obtained. The symmetries of patterns resulting from the coupled modes may be different from those of their parents, such as the cluster hexagon pattern and square pattern. With the increase of perturbation and coupling intensity, the nonlinear system will con-vert between a static pattern and a dynamic pattern when the Turing instability and Hopf instability happen in the nonlinear system. Besides the wavenumber ratio and intensity ratio of the two different wavelength Turing modes, perturbation and coupling intensity play an important role in the pattern formation and selection. According to the simulation results, we find that two modes with different symmetries can also be in the spatial resonance under certain conditions, and complex patterns appear in the two-layer coupled reaction diffusion systems.

  16. Two-Layer Tight Frame Sparsifying Model for Compressed Sensing Magnetic Resonance Imaging

    Science.gov (United States)

    Peng, Xi; Dong, Pei

    2016-01-01

    Compressed sensing magnetic resonance imaging (CSMRI) employs image sparsity to reconstruct MR images from incoherently undersampled K-space data. Existing CSMRI approaches have exploited analysis transform, synthesis dictionary, and their variants to trigger image sparsity. Nevertheless, the accuracy, efficiency, or acceleration rate of existing CSMRI methods can still be improved due to either lack of adaptability, high complexity of the training, or insufficient sparsity promotion. To properly balance the three factors, this paper proposes a two-layer tight frame sparsifying (TRIMS) model for CSMRI by sparsifying the image with a product of a fixed tight frame and an adaptively learned tight frame. The two-layer sparsifying and adaptive learning nature of TRIMS has enabled accurate MR reconstruction from highly undersampled data with efficiency. To solve the reconstruction problem, a three-level Bregman numerical algorithm is developed. The proposed approach has been compared to three state-of-the-art methods over scanned physical phantom and in vivo MR datasets and encouraging performances have been achieved. PMID:27747226

  17. Analysis and Control of Two-Layer Frenkel-Kontorova Model

    Institute of Scientific and Technical Information of China (English)

    TANG Wen-Yan; QU Zhi-Hua; GUO Yi

    2011-01-01

    A one-dimensional two-layer Frenkel-Kontorova model is studied.Firstly,a feedback tracking control law is given.Then,the boundedness result for the error states of single particles of the model is derived using the Lyapunov Method.Especially,the motion of single particles can be approximated analytically for the case of sufficiently large targeted velocity.Simulations illustrate the accuracy of the derived results.Recently,the Frenkel-Kontorova (FK) model,which describes a chain of classical particles interacting with its nearest neighbors and subjected to a periodic one-site potential,has become a useful tool to study nanotribology.[1-6] There are several generalizations of the FK model that have been introduced with the hope of understanding friction dynamics at nanoscale.These models include a manylayer model with harmonic interactions,the FrenkelKontorova-Tomlinson model (FKT) and the singlelayer model with harmonic interactions.%A one-dimensional two-layer Frenkel-Kontorova model is studied. Firstly, a feedback tracking control law is given. Then, the boundedness result for the error states of single particles of the model is derived using the Lyapunov Method. Especially, the motion of single particles can be approximated analytically for the case of sufficiently large targeted velocity. Simulations illustrate the accuracy of the derived results.

  18. Reverse-feeding effect of epidemic by propagators in two-layered networks

    Science.gov (United States)

    Dayu, Wu; Yanping, Zhao; Muhua, Zheng; Jie, Zhou; Zonghua, Liu

    2016-02-01

    Epidemic spreading has been studied for a long time and is currently focused on the spreading of multiple pathogens, especially in multiplex networks. However, little attention has been paid to the case where the mutual influence between different pathogens comes from a fraction of epidemic propagators, such as bisexual people in two separated groups of heterosexual and homosexual people. We here study this topic by presenting a network model of two layers connected by impulsive links, in contrast to the persistent links in each layer. We let each layer have a distinct pathogen and their interactive infection is implemented by a fraction of propagators jumping between the corresponding pairs of nodes in the two layers. By this model we show that (i) the propagators take the key role to transmit pathogens from one layer to the other, which significantly influences the stabilized epidemics; (ii) the epidemic thresholds will be changed by the propagators; and (iii) a reverse-feeding effect can be expected when the infective rate is smaller than its threshold of isolated spreading. A theoretical analysis is presented to explain the numerical results. Project supported by the National Natural Science Foundation of China (Grant Nos. 11135001, 11375066, and 11405059) and the National Basic Key Program of China (Grant No. 2013CB834100).

  19. NUMERICAL SIMULATION OF HEAD-CUT WITH A TWO-LAYERED BED

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Gully erosion is one of the main causes of top soil loss, land deterioration and sources of sediment deposition in streams. Headcut often occurs in the gully erosion process when erodability of the soil layers varies, and the gully cuts through a hard layer at a point. A scouring hole appears downstream of the head cut which migrates upstream due to strong erosion in the scour hole. This paper presents numerical analyses of turbulent flow and sediment transport processes of a head-cut associated with a two-layer soil stratigraphic formation. The flow in the scour hole is three-dimensional induced by the water jet from the brink of the top layer; the sediment transport model considers sediment entrainment by the impinging jet, erosion underneath the hard layer and the retreat of the brink of the hard layer. The 3D flow simulation in the scour hole and the scouring process was verified with physical model data. The two-layer head cut migration is simulated with different flow and soil parameters, the trends of the simulated results reasonably revealed contributions of these parameters to the scouring and migration process.

  20. Two-layer wireless distributed sensor/control network based on RF

    Science.gov (United States)

    Feng, Li; Lin, Yuchi; Zhou, Jingjing; Dong, Guimei; Xia, Guisuo

    2006-11-01

    A project of embedded Wireless Distributed Sensor/Control Network (WDSCN) based on RF is presented after analyzing the disadvantages of traditional measure and control system. Because of high-cost and complexity, such wireless techniques as Bluetooth and WiFi can't meet the needs of WDSCN. The two-layer WDSCN is designed based on RF technique, which operates in the ISM free frequency channel with low power and high transmission speed. Also the network is low cost, portable and moveable, integrated with the technologies of computer network, sensor, microprocessor and wireless communications. The two-layer network topology is selected in the system; a simple but efficient self-organization net protocol is designed to fit the periodic data collection, event-driven and store-and-forward. Furthermore, adaptive frequency hopping technique is adopted for anti-jamming apparently. The problems about power reduction and synchronization of data in wireless system are solved efficiently. Based on the discussion above, a measure and control network is set up to control such typical instruments and sensors as temperature sensor and signal converter, collect data, and monitor environmental parameters around. This system works well in different rooms. Experiment results show that the system provides an efficient solution to WDSCN through wireless links, with high efficiency, low power, high stability, flexibility and wide working range.

  1. Study on Vertical Falling Film Absorption Heat Transformer for Low Grade Waste Heat Recovery%低品位余热回收的立式降膜吸收式热变换器研究

    Institute of Scientific and Technical Information of China (English)

    隋军; 刘锋; 郭培军; 金红光

    2015-01-01

    In distributed energy systems driven by internal combustion engines, over 30%of input system energy is taken away by 90 oC~99 oC jacket water whose energy level can be upgraded by absorption heat transformers (AHT). A design method of the AHT driven by the waste heat of jacket water was developed in this study. Then a vertical falling film AHT facility with 20 kW heating capacity was manufactured. And a distributed energy system with AHT was proposed. In the system, the superheated steam was made with waste heat of smoke and jacket water, which improves the energy efficiency.%内燃机分布式能源系统中,90℃~99℃缸套水带走的热量约占系统输入热量的30%,利用吸收式热变换器(AHT)可以有效提升缸套水余热品位。本文提出一种由内燃机缸套水余热驱动的 AHT 的设计方法,研制了制热功率为20 kW的立式降膜AHT机组,并提出集成热变换器的分布式热电联产系统,利用烟气和缸套水余热生产过热蒸汽,实现节能。

  2. Investigation on Purification of Dimethyl Terephthalate Using Falling Film Crystallization%降膜结晶法精制对苯二甲酸二甲酯的研究

    Institute of Scientific and Technical Information of China (English)

    孙绪江; 张军; 齐彦伟; 符强

    2001-01-01

    对苯二甲酸二甲酯(DMT)是生产聚酯的基本原料,由于精制工艺流程长,导致DMT成本高,降低了竞争力。本文将降膜结晶技术用于DMT的分离精制,得到了高纯度的产品,讨论了各种操作条件对结晶速度和产品纯度的影响,确定了最优操作条件。%Dimethyl terephthalate(DMT)is the main raw material for producingpolyester fiber.Because its purification process is long,so the cost is very high.In this paper,the falling film crystallization is used to separate and purify DMT.The product of high purity is obtained.The influence of various operating conditions on the crystallization rate and product purity have been investigated.The optimum operating condition is given.

  3. Falls in Parkinson's disease.

    NARCIS (Netherlands)

    Grimbergen, Y.A.M.; Munneke, M.; Bloem, B.R.

    2004-01-01

    PURPOSE OF REVIEW: To summarize the latest insights into the clinical significance, assessment, pathophysiology and treatment of falls in Parkinson's disease. RECENT FINDINGS: Recent studies have shown that falls are common in Parkinson's disease, even when compared with other fall-prone populations

  4. First Aid: Falls

    Science.gov (United States)

    ... Your 1- to 2-Year-Old First Aid: Falls KidsHealth > For Parents > First Aid: Falls Print A A A en español Folleto de instructiones: Caídas (Falls) With all the running, climbing, and exploring kids ...

  5. Wave turbulence in a two-layer fluid: coupling between free surface and interface waves

    CERN Document Server

    Issenmann, Bruno; Falcon, Eric

    2016-01-01

    We experimentally study gravity-capillary wave turbulence on the interface between two immiscible fluids of close density with free upper surface. We locally measure the wave height at the interface between both fluids by means of a highly sensitive laser Doppler vibrometer. We show that the inertial range of the capillary wave turbulence regime is significantly extended when the upper fluid depth is increased: The crossover frequency between the gravity and capillary wave turbulence regimes is found to decrease whereas the dissipative cut-off frequency of the spectrum is found to increase. We explain most of these observations by the progressive decoupling between waves propagating at the interface and the ones at the free surface, using the full dispersion relation of gravity-capillary waves in a two-layer fluid of finite depths.s.

  6. Spin-3/2 Ising model AFM/AFM two-layer lattice with crystal field

    Institute of Scientific and Technical Information of China (English)

    Erhan Albayrak; Ali Yigit

    2009-01-01

    The spin-3/2 Ising model is investigated for the case of antiferromagnetic (AFM/AFM) interactions on the two-layer Bethe lattice by using the exact recursion relations in the pairwise approach for given coordination numbers q = 3, 4 and 6 when the layers are under the influences of equal external magnetic and equal crystal fields. The ground state, (GS) phase diagrams are obtained on the different planes in detail and then the temperature-dependent phase diagrams of the system are calculated accordingly. It is observed that the system presents both second- and first-order phase transitions for all q, therefore, tricritical points. It is also found that the system exhibits double-critical end points and isolated points. The model aiso presents two Néel temperatures, T_N, and the existence of which leads to the reentrant behaviour.

  7. Two-layer interfacial flows beyond the Boussinesq approximation: a Hamiltonian approach

    Science.gov (United States)

    Camassa, R.; Falqui, G.; Ortenzi, G.

    2017-02-01

    The theory of integrable systems of Hamiltonian PDEs and their near-integrable deformations is used to study evolution equations resulting from vertical-averages of the Euler system for two-layer stratified flows in an infinite two-dimensional channel. The Hamiltonian structure of the averaged equations is obtained directly from that of the Euler equations through the process of Hamiltonian reduction. Long-wave asymptotics together with the Boussinesq approximation of neglecting the fluids’ inertia is then applied to reduce the leading order vertically averaged equations to the shallow-water Airy system, albeit in a non-trivial way. The full non-Boussinesq system for the dispersionless limit can then be viewed as a deformation of this well known equation. In a perturbative study of this deformation, a family of approximate constants of the motion are explicitly constructed and used to find local solutions of the evolution equations by means of hodograph-like formulae.

  8. Central-Upwind Schemes for Two-Layer Shallow Water Equations

    KAUST Repository

    Kurganov, Alexander

    2009-01-01

    We derive a second-order semidiscrete central-upwind scheme for one- and two-dimensional systems of two-layer shallow water equations. We prove that the presented scheme is well-balanced in the sense that stationary steady-state solutions are exactly preserved by the scheme and positivity preserving; that is, the depth of each fluid layer is guaranteed to be nonnegative. We also propose a new technique for the treatment of the nonconservative products describing the momentum exchange between the layers. The performance of the proposed method is illustrated on a number of numerical examples, in which we successfully capture (quasi) steady-state solutions and propagating interfaces. © 2009 Society for Industrial and Applied Mathematics.

  9. Two-layer fragile watermarking method secured with chaotic map for authentication of digital Holy Quran.

    Science.gov (United States)

    Khalil, Mohammed S; Kurniawan, Fajri; Khan, Muhammad Khurram; Alginahi, Yasser M

    2014-01-01

    This paper presents a novel watermarking method to facilitate the authentication and detection of the image forgery on the Quran images. Two layers of embedding scheme on wavelet and spatial domain are introduced to enhance the sensitivity of fragile watermarking and defend the attacks. Discrete wavelet transforms are applied to decompose the host image into wavelet prior to embedding the watermark in the wavelet domain. The watermarked wavelet coefficient is inverted back to spatial domain then the least significant bits is utilized to hide another watermark. A chaotic map is utilized to blur the watermark to make it secure against the local attack. The proposed method allows high watermark payloads, while preserving good image quality. Experiment results confirm that the proposed methods are fragile and have superior tampering detection even though the tampered area is very small.

  10. Transient response of a vertical electric dipole (VED) on a two-layer medium

    Science.gov (United States)

    Poh, S. Y.; Kong, J. A.

    The transient electromagnetic radiation by a vertical electric dipole on a two-layer medium is analyzed using the double deformation technique, which is a modal technique based on identification of singularities in the complex frequency and wavenumber planes. Previous application of the double deformation technique to the solution of this problem is incomplete in the early time response. In this paper it is shown that the existence of a pole locus on the negative imaginary frequency axis, which dominates the early time response, proves crucial in obtaining the solution for all times. A variety of combinations of parameters are used to illustrate the double deformation technique, and results will be compared with those obtained via explicit inversion, and a single deformation method.

  11. Two-Layer Coding Rate Optimization in Relay-Aided Systems

    DEFF Research Database (Denmark)

    Sun, Fan

    2011-01-01

    We consider a three-node transmission system, where a source node conveys a data block to a destination node with the help of a half-duplex decode and-forward (DF) relay node. The whole data block is transmitted as a sequence of packets. For reliable transmission in the three-node system, a two......-layer coding scheme is proposed, where physical layer channel coding is utilized within each packet for error-correction and random network coding is applied on top of channel coding for network error-control. There is a natural tradeoff between the physical layer coding rate and the network coding rate given...... requirement. Numerical results are also provided to show the optimized physical layer coding and network coding rate pairs in different system scenarios....

  12. The peak effect (PE) region of the antiferromagnetic two layer Ising nanographene

    Energy Technology Data Exchange (ETDEWEB)

    Şarlı, Numan, E-mail: numansarli82@gmail.com [Institute of Science, Erciyes University, 38039 Kayseri (Turkey); Akbudak, Salih [Department of Physics, Adiyaman University, 02100 Adiyaman (Turkey); Department of Nanotechnology and Nanomedicine, Hacettepe University, 06800 Ankara (Turkey); Ellialtıoğlu, Mehmet Recai [Department of Physics Engineering, Hacettepe University, 06800 Ankara (Turkey)

    2014-11-01

    In this work, the magnetic properties of the ferromagnetic and antiferromagnetic two layer spin-1/2 Ising nanographene systems are investigated within the effective field theory. We find that the magnetizations and the hysteresis behaviors of the central graphene atoms are similar to those of the edge graphene atoms in the ferromagnetic case. But, they are quite different in the antiferromagnetic case. The antiferromagnetic central graphene atoms exhibit type II superconductivity and they have triple hysteresis loop. The peak effect (PE) region is observed on the hysteresis curves of the antiferromagnetic Ising nanographene system. Therefore, we suggest that there is a strong relationship between the antiferromagnetism and the peak effect. Our results are in agreement with some experimental works in recent literature.

  13. STRESS ANALYSIS AND BURST PRESSURE DETERMINATION OF TWO LAYER COMPOUND PRESSURE VESSEL

    Directory of Open Access Journals (Sweden)

    HARERAM LOHAR

    2013-02-01

    Full Text Available Multilayer pressure vessel is designed to work under high-pressure condition. This paper introduces the stress analysis and the burst pressure calculation of a two-layer shrink fitted pressure vessel. In the shrink-fitting problems, considering long hollow cylinders, the plane strain hypothesis can be regarded as more natural. Generally hoops stress distribution is non-linear and sharply reduced toward the outer surface. By shrink fitting concentric shells towards the inner shells are placed in residual compression so that the initial compressive hoop stress must be relieved by internal pressure before hoop tensile stress are developed. Therefore the maximum hoop stress will be reduced, resulting more burst pressure. The analytical results of stress distribution and burst pressure is calculated and validated by ANSYS Workbench results.

  14. Testing the Two-Layer Model for Correcting Clear Sky Reflectance near Clouds

    Science.gov (United States)

    Wen, Guoyong; Marshak, Alexander; Evans, Frank; Varnai, Tamas; Levy, Rob

    2015-01-01

    A two-layer model (2LM) was developed in our earlier studies to estimate the clear sky reflectance enhancement due to cloud-molecular radiative interaction at MODIS at 0.47 micrometers. Recently, we extended the model to include cloud-surface and cloud-aerosol radiative interactions. We use the LES/SHDOM simulated 3D true radiation fields to test the 2LM for reflectance enhancement at 0.47 micrometers. We find: The simple model captures the viewing angle dependence of the reflectance enhancement near cloud, suggesting the physics of this model is correct; the cloud-molecular interaction alone accounts for 70 percent of the enhancement; the cloud-surface interaction accounts for 16 percent of the enhancement; the cloud-aerosol interaction accounts for an additional 13 percent of the enhancement. We conclude that the 2LM is simple to apply and unbiased.

  15. Study of electronic and optical properties of two-layered hydrogenated aluminum nitrate nanosheet

    Science.gov (United States)

    Faghihzadeh, Somayeh; Shahtahmasebi, Nasser; Rezaee Roknabadi, Mahmood

    2017-09-01

    First principle calculations based on density functional theory using GW approximation and two particle Bethe-Salpeter equation with electron-hole effect were performed to investigate electronic structure and optical properties of two-layered hydrogenated AlN. According to many body green function due to decrease in dimension and considering electron-electron effect, direct (indirect) band gap change from 2 (1.01) eV to 4.83 (3.62) eV. The first peak in imaginary part of dielectric function was observed in parallel direction to a plane obtaining 3.4 was achieved by bound exciton states possess 1.39 eV. The first absorption peak was seen in two parallel and perpendicular directions to a plane which are in UV region.

  16. Initial stresses in two-layer metal domes due to imperfections of their production and assemblage

    Directory of Open Access Journals (Sweden)

    Lebed Evgeniy Vasil’evich

    2015-04-01

    Full Text Available The process of construction of two-layer metal domes is analyzed to illustrate the causes of initial stresses in the bars of their frames. It has been noticed that it is impossible to build such structures with ideal geometric parameters because of imperfections caused by objective reasons. These imperfections cause difficulties in the process of connection of the elements in the joints. The paper demonstrates the necessity of fitting operations during assemblage that involve force fitting and yield initial stresses due to imperfections. The authors propose a special method of computer modeling of enforced elimination of possible imperfections caused by assemblage process and further confirm the method by an analysis of a concrete metal dome.

  17. Analysis of data recorded by the LCTPC equipped with a two layer GEM-system

    CERN Document Server

    Ljunggren, M

    2012-01-01

    wire based readout. The prototype TPC is placed in a 1 Tesla magnet at DESY and tested using an electron beam. Analyses of data taken during two different measurement series, in 2009 and 2010, are presented here. The TPC was instrumented with a two layer GEM system and read out using modified electronics from the ALICE experiment, including the programmable charge sensitive preamp-shaper PCA16. The PCA16 chip has a number of programmable parameters which allows studies to determine the settings optimal to the final TPC. Here, the impact of the shaping time on the space resolution in the drift direction was studied. It was found that a shaping time of 60 ns is the b...

  18. INFLUENCE OF TEMPERATURE ON BEHAVIOR OF THE INTERFACIAL CRACK BETWEEN THE TWO LAYERS

    Directory of Open Access Journals (Sweden)

    Jelena M Djoković

    2010-01-01

    Full Text Available In this paper is considered a problem of the semi-infinite crack at the interface between the two elastic isotropic layers in conditions of the environmental temperature change. The energy release rate needed for the crack growth along the interface was determined, for the case when the two-layered sample is cooled from the temperature of the layers joining down to the room temperature. It was noticed that the energy release rate increases with the temperature difference increase. In the paper is also presented the distribution of stresses in layers as a function of the temperature and the layers' thickness variations. Analysis is limited to the case when the bimaterial sample is exposed to uniform temperature.

  19. High Performance Hybrid Two Layer Router Architecture for FPGAs Using Network On Chip

    CERN Document Server

    Ezhumalai, P; Arun, C; Sakthivel, P; Sridharan, D

    2010-01-01

    Networks on Chip is a recent solution paradigm adopted to increase the performance of Multicore designs. The key idea is to interconnect various computation modules (IP cores) in a network fashion and transport packets simultaneously across them, thereby gaining performance. In addition to improving performance by having multiple packets in flight, NoCs also present a host of other advantages including scalability, power efficiency, and component reuse through modular design. This work focuses on design and development of high performance communication architectures for FPGAs using NoCs Once completely developed, the above methodology could be used to augment the current FPGA design flow for implementing multicore SoC applications. We design and implement an NoC framework for FPGAs, MultiClock OnChip Network for Reconfigurable Systems (MoCReS). We propose a novel microarchitecture for a hybrid two layer router that supports both packetswitched communications, across its local and directional ports, as well as...

  20. The fuzzy coat of pathological human Tau fibrils is a two-layered polyelectrolyte brush.

    Science.gov (United States)

    Wegmann, Susanne; Medalsy, Izhar D; Mandelkow, Eckhard; Müller, Daniel J

    2013-01-22

    The structure and properties of amyloid-like Tau fibrils accumulating in neurodegenerative diseases have been debated for decades. Although the core of Tau fibrils assembles from short β-strands, the properties of the much longer unstructured Tau domains protruding from the fibril core remain largely obscure. Applying immunogold transmission EM, and force-volume atomic force microscopy (AFM), we imaged human Tau fibrils at high resolution and simultaneously mapped their mechanical and adhesive properties. Tau fibrils showed a ≈ 16-nm-thick fuzzy coat that resembles a two-layered polyelectrolyte brush, which is formed by the unstructured short C-terminal and long N-terminal Tau domains. The mechanical and adhesive properties of the fuzzy coat are modulated by electrolytes and pH, and thus by the cellular environment. These unique properties of the fuzzy coat help in understanding how Tau fibrils disturb cellular interactions and accumulate in neurofibrillary tangles.

  1. Sparse/DCT (S/DCT) two-layered representation of prediction residuals for video coding.

    Science.gov (United States)

    Kang, Je-Won; Gabbouj, Moncef; Kuo, C-C Jay

    2013-07-01

    In this paper, we propose a cascaded sparse/DCT (S/DCT) two-layer representation of prediction residuals, and implement this idea on top of the state-of-the-art high efficiency video coding (HEVC) standard. First, a dictionary is adaptively trained to contain featured patterns of residual signals so that a high portion of energy in a structured residual can be efficiently coded via sparse coding. It is observed that the sparse representation alone is less effective in the R-D performance due to the side information overhead at higher bit rates. To overcome this problem, the DCT representation is cascaded at the second stage. It is applied to the remaining signal to improve coding efficiency. The two representations successfully complement each other. It is demonstrated by experimental results that the proposed algorithm outperforms the HEVC reference codec HM5.0 in the Common Test Condition.

  2. Development of an algebraic stress/two-layer model for calculating thrust chamber flow fields

    Science.gov (United States)

    Chen, C. P.; Shang, H. M.; Huang, J.

    1993-01-01

    Following the consensus of a workshop in Turbulence Modeling for Liquid Rocket Thrust Chambers, the current effort was undertaken to study the effects of second-order closure on the predictions of thermochemical flow fields. To reduce the instability and computational intensity of the full second-order Reynolds Stress Model, an Algebraic Stress Model (ASM) coupled with a two-layer near wall treatment was developed. Various test problems, including the compressible boundary layer with adiabatic and cooled walls, recirculating flows, swirling flows and the entire SSME nozzle flow were studied to assess the performance of the current model. Detailed calculations for the SSME exit wall flow around the nozzle manifold were executed. As to the overall flow predictions, the ASM removes another assumption for appropriate comparison with experimental data, to account for the non-isotropic turbulence effects.

  3. Cumulative second-harmonic generation of Lamb waves propagating in a two-layered solid plate

    Institute of Scientific and Technical Information of China (English)

    Xiang Yan-Xun; Deng Ming-Xi

    2008-01-01

    The physical process of cumulative second-harmonic generation of Lamb waves propagating in a two-layered solid plate is presented by using the second-order perturbation and the technique of nonlinear reflection of acoustic waves at an interface.In general,the cumulative second-harmonic generation of a dispersive guided wave propagation does not occur.However,the present paper shows that the second-harmonic of Lamb wave propagation arising from the nonlinear interaction of the partial bulk acoustic waves and the restriction of the three boundaries of the solid plates does have a cumulative growth effect if some conditions are satisfied.Through boundary condition and initial condition of excitation,the analytical expression of cumulative second-harmonic of Lamb waves propagation is determined.Numerical results show the cumulative effect of Lamb waves on second-harmonic field patterns.

  4. Convergent flow in a two-layer system and mountain building

    CERN Document Server

    Perazzo, Carlos Alberto

    2009-01-01

    With the purpose of modelling the process of mountain building, we investigate the evolution of the ridge produced by the convergent motion of a system consisting of two layers of liquids that differ in density and viscosity to simulate the crust and the upper mantle that form a lithospheric plate. We assume that the motion is driven by basal traction. Assuming isostasy, we derive a nonlinear differential equation for the evolution of the thickness of the crust. We solve this equation numerically to obtain the profile of the range. We find an approximate self-similar solution that describes reasonably well the process and predicts simple scaling laws for the height and width of the range as well as the shape of the transversal profile. We compare the theoretical results with the profiles of real mountain belts and find and excellent agreement.

  5. TWO-LAYER SECURE PREVENTION MECHANISM FOR REDUCING E-COMMERCE SECURITY RISKS

    Directory of Open Access Journals (Sweden)

    Sen-Tarng Lai

    2015-12-01

    Full Text Available E-commerce is an important information system in the network and digital age. However, the network intrusion, malicious users, virus attack and system security vulnerabilities have continued to threaten the operation of the e-commerce, making e-commerce security encounter serious test. How to improve ecommerce security has become a topic worthy of further exploration. Combining routine security test and security event detection procedures, this paper proposes the Two-Layer Secure Prevention Mechanism (TLSPM. Applying TLSPM, routine security test procedure can identify security vulnerability and defect, and develop repair operations. Security event detection procedure can timely detect security event, and assist follow repair. TLSPM can enhance the e-commerce security and effectively reduce the security risk of e-commerce critical data and asset.

  6. Calculation of AC loss in two-layer superconducting cable with equal currents in the layers

    Science.gov (United States)

    Erdogan, Muzaffer

    2016-12-01

    A new method for calculating AC loss of two-layer SC power transmission cables using the commercial software Comsol Multiphysics, relying on the approach of the equal partition of current between the layers is proposed. Applying the method to calculate the AC-loss in a cable composed of two coaxial cylindrical SC tubes, the results are in good agreement with the analytical ones of duoblock model. Applying the method to calculate the AC-losses of a cable composed of a cylindrical copper former, surrounded by two coaxial cylindrical layers of superconducting tapes embedded in an insulating medium with tape-on-tape and tape-on-gap configurations are compared. A good agreement between the duoblock model and the numerical results for the tape-on-gap cable is observed.

  7. 2-DE combined with two-layer feature selection accurately establishes the origin of oolong tea.

    Science.gov (United States)

    Chien, Han-Ju; Chu, Yen-Wei; Chen, Chi-Wei; Juang, Yu-Min; Chien, Min-Wei; Liu, Chih-Wei; Wu, Chia-Chang; Tzen, Jason T C; Lai, Chien-Chen

    2016-11-15

    Taiwan is known for its high quality oolong tea. Because of high consumer demand, some tea manufactures mix lower quality leaves with genuine Taiwan oolong tea in order to increase profits. Robust scientific methods are, therefore, needed to verify the origin and quality of tea leaves. In this study, we investigated whether two-dimensional gel electrophoresis (2-DE) and nanoscale liquid chromatography/tandem mass spectroscopy (nano-LC/MS/MS) coupled with a two-layer feature selection mechanism comprising information gain attribute evaluation (IGAE) and support vector machine feature selection (SVM-FS) are useful in identifying characteristic proteins that can be used as markers of the original source of oolong tea. Samples in this study included oolong tea leaves from 23 different sources. We found that our method had an accuracy of 95.5% in correctly identifying the origin of the leaves. Overall, our method is a novel approach for determining the origin of oolong tea leaves.

  8. A Two-Layer Mathematical Modelling of Drug Delivery to Biological Tissues

    CERN Document Server

    Chakravarty, Koyel

    2016-01-01

    Local drug delivery has received much recognition in recent years, yet it is still unpredictable how drug efficacy depends on physicochemical properties and delivery kinetics. The purpose of the current study is to provide a useful mathematical model for drug release from a drug delivery device and consecutive drug transport in biological tissue, thereby aiding the development of new therapeutic drug by a systemic approach. In order to study the complete process, a two-layer spatio-temporal model depicting drug transport between the coupled media is presented. Drug release is described by considering solubilisation dynamics of drug particle, diffusion of the solubilised drug through porous matrix and also some other processes like reversible dissociation / recrystallization, drug particle-receptor binding and internalization phenomena. The model has led to a system of partial differential equations describing the important properties of drug kinetics. This model contributes towards the perception of the roles...

  9. Some considerations on numerical schemes for treating hyperbolicity issues in two-layer models

    Science.gov (United States)

    Sarno, L.; Carravetta, A.; Martino, R.; Papa, M. N.; Tai, Y.-C.

    2017-02-01

    Multi-layer depth-averaged models are widely employed in various hydraulic engineering applications. Yet, such models are not strictly hyperbolic. Their equation systems typically lose hyperbolicity when the relative velocities between layers become too large, which is associated with Kelvin-Helmholtz instabilities involving turbulent momentum exchanges between the layers. Focusing on the two-layer case, we present a numerical improvement that locally avoids the loss of hyperbolicity. The proposed modification introduces an additional momentum exchange between layers, whose value is iteratively calculated to be strictly sufficient to keep the system hyperbolic. The approach can be easily implemented in any finite volume scheme and there is no limitation concerning the density ratio between layers. Numerical examples, employing both HLL-type and Roe-type approximate Riemann solvers, are reported to validate the method and its key features.

  10. A TWO-LAYER RECURRENT NEURAL NETWORK BASED APPROACH FOR OVERLAY MULTICAST

    Institute of Scientific and Technical Information of China (English)

    Liu Shidong; Zhang Shunyi; Zhou Jinquan; Qiu Gong'an

    2008-01-01

    Overlay multicast has become one of the most promising multicast solutions for IP network, and Neutral Network(NN) has been a good candidate for searching optimal solutions to the constrained shortest routing path in virtue of its powerful capacity for parallel computation. Though traditional Hopfield NN can tackle the optimization problem, it is incapable of dealing with large scale networks due to the large number of neurons. In this paper, a neural network for overlay multicast tree computation is presented to reliably implement routing algorithm in real time. The neural network is constructed as a two-layer recurrent architecture, which is comprised of Independent Variable Neurons (IDVN) and Dependent Variable Neurons (DVN), according to the independence of the decision variables associated with the edges in directed graph. Compared with the heuristic routing algorithms, it is characterized as shorter computational time, fewer neurons, and better precision.

  11. Two-layer networked learning control using self-learning fuzzy control algorithms

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Since the existing single-layer networked control systems have some inherent limitations and cannot effectively handle the problems associated with unreliable networks, a novel two-layer networked learning control system (NLCS) is proposed in this paper. Its lower layer has a number of local controllers that are operated independently, and its upper layer has a learning agent that communicates with the independent local controllers in the lower layer. To implement such a system, a packet-discard strategy is firstly developed to deal with network-induced delay and data packet loss. A cubic spline interpolator is then employed to compensate the lost data. Finally, the output of the learning agent based on a novel radial basis function neural network (RBFNN) is used to update the parameters of fuzzy controllers. A nonlinear heating, ventilation and air-conditioning (HVAC) system is used to demonstrate the feasibility and effectiveness of the proposed system.

  12. Artery buckling analysis using a two-layered wall model with collagen dispersion.

    Science.gov (United States)

    Mottahedi, Mohammad; Han, Hai-Chao

    2016-07-01

    Artery buckling has been proposed as a possible cause for artery tortuosity associated with various vascular diseases. Since microstructure of arterial wall changes with aging and diseases, it is essential to establish the relationship between microscopic wall structure and artery buckling behavior. The objective of this study was to developed arterial buckling equations to incorporate the two-layered wall structure with dispersed collagen fiber distribution. Seven porcine carotid arteries were tested for buckling to determine their critical buckling pressures at different axial stretch ratios. The mechanical properties of these intact arteries and their intima-media layer were determined via pressurized inflation test. Collagen alignment was measured from histological sections and modeled by a modified von-Mises distribution. Buckling equations were developed accordingly using microstructure-motivated strain energy function. Our results demonstrated that collagen fibers disperse around two mean orientations symmetrically to the circumferential direction (39.02°±3.04°) in the adventitia layer; while aligning closely in the circumferential direction (2.06°±3.88°) in the media layer. The microstructure based two-layered model with collagen fiber dispersion described the buckling behavior of arteries well with the model predicted critical pressures match well with the experimental measurement. Parametric studies showed that with increasing fiber dispersion parameter, the predicted critical buckling pressure increases. These results validate the microstructure-based model equations for artery buckling and set a base for further studies to predict the stability of arteries due to microstructural changes associated with vascular diseases and aging.

  13. Quantification of the specific yield in a two-layer hard-rock aquifer model

    Science.gov (United States)

    Durand, Véronique; Léonardi, Véronique; de Marsily, Ghislain; Lachassagne, Patrick

    2017-08-01

    Hard rock aquifers (HRA) have long been considered to be two-layer systems, with a mostly capacitive layer just below the surface, the saprolite layer, and a mainly transmissive layer underneath, the fractured layer. Although this hydrogeological conceptual model is widely accepted today within the scientific community, it is difficult to quantify the respective storage properties of each layer with an equivalent porous medium model. Based on an HRA field site, this paper attempts to quantify in a distinct manner the respective values of the specific yield (Sy) in the saprolite and the fractured layer, with the help of a deterministic hydrogeological model. The study site is the Plancoët migmatitic aquifer located in north-western Brittany, France, with piezometric data from 36 observation wells surveyed every two weeks for eight years. Whereas most of the piezometers (26) are located where the water table lies within the saprolite, thus representing the specific yield of the unconfined layer (Sy1), 10 of them are representative of the unconfined fractured layer (Sy2), due to their position where the saprolite is eroded or unsaturated. The two-layer model, based on field observations of the layer geometry, runs with the MODFLOW code. 81 values of the Sy1/Sy2 parameter sets were tested manually, as an inverse calibration was not able to calibrate these parameters. In order to calibrate the storage properties, a new quality-of-fit criterion called ;AdVar; was also developed, equal to the mean squared deviation of the seasonal piezometric amplitude variation. Contrary to the variance, AdVar is able to select the best values for the specific yield in each layer. It is demonstrated that the saprolite layer is about 2.5 times more capacitive than the fractured layer, with Sy1 = 10% (7% < Sy1 < 15%) against Sy2 = 2% (1% < Sy2 < 3%), in this particular example.

  14. Single- and Two-Layer Coatings of Metal Blends onto Carbon Steel: Mechanical, Wear, and Friction Characterizations

    Science.gov (United States)

    Yilbas, Bekir Sami; Kumar, Aditya; Bhushan, Bharat

    2014-01-01

    Single- and two-layer coatings were deposited onto carbon steel using a high-velocity oxy-fuel deposition gun. The two-layer coating consisted of a top layer of tungsten carbide cobalt/nickel alloy blend that provides wear resistance and a bottom layer of iron/molybdenum blend that provides corrosion resistance. The morphological changes in the single- and two-layer coatings were examined using scanning electron microscopy. The residual stresses formed on the surface of various coatings were determined from x-ray diffraction data. Nanomechanical properties were measured using the nanoindentation technique. Microhardness and fracture toughness were measured incorporating the microindentation tests. Macrowear and macrofriction characteristics were measured using the pin-on-disk testing apparatus. The goal of this study was to ensure that the mechanical properties, friction, and wear resistance of the two-layer coating are similar to that of the single-layer coating.

  15. Storage capacity and learning algorithms for two-layer neural networks

    Science.gov (United States)

    Engel, A.; Köhler, H. M.; Tschepke, F.; Vollmayr, H.; Zippelius, A.

    1992-05-01

    A two-layer feedforward network of McCulloch-Pitts neurons with N inputs and K hidden units is analyzed for N-->∞ and K finite with respect to its ability to implement p=αN random input-output relations. Special emphasis is put on the case where all hidden units are coupled to the output with the same strength (committee machine) and the receptive fields of the hidden units either enclose all input units (fully connected) or are nonoverlapping (tree structure). The storage capacity is determined generalizing Gardner's treatment [J. Phys. A 21, 257 (1988); Europhys. Lett. 4, 481 (1987)] of the single-layer perceptron. For the treelike architecture, a replica-symmetric calculation yields αc~ √K for a large number K of hidden units. This result violates an upper bound derived by Mitchison and Durbin [Biol. Cybern. 60, 345 (1989)]. One-step replica-symmetry breaking gives lower values of αc. In the fully connected committee machine there are in general correlations among different hidden units. As the limit of capacity is approached, the hidden units are anticorrelated: One hidden unit attempts to learn those patterns which have not been learned by the others. These correlations decrease as 1/K, so that for K-->∞ the capacity per synapse is the same as for the tree architecture, whereas for small K we find a considerable enhancement for the storage per synapse. Numerical simulations were performed to explicitly construct solutions for the tree as well as the fully connected architecture. A learning algorithm is suggested. It is based on the least-action algorithm, which is modified to take advantage of the two-layer structure. The numerical simulations yield capacities p that are slightly more than twice the number of degrees of freedom, while the fully connected net can store relatively more patterns than the tree. Various generalizations are discussed. Variable weights from hidden to output give the same results for the storage capacity as does the committee

  16. Optical measurements of absorption changes in two-layered diffusive media

    Energy Technology Data Exchange (ETDEWEB)

    Fabbri, Francesco [Department of Biomedical Engineering, Bioengineering Center, Tufts University, 4 Colby Street, Medford, MA 02155 (United States); Sassaroli, Angelo [Department of Biomedical Engineering, Bioengineering Center, Tufts University, 4 Colby Street, Medford, MA 02155 (United States); Henry, Michael E [McLean Hospital and Department of Psychiatry, Harvard Medical School, 115 Mill Street, Belmont, MA 02478 (United States); Fantini, Sergio [Department of Biomedical Engineering, Bioengineering Center, Tufts University, 4 Colby Street, Medford, MA 02155 (United States)

    2004-04-07

    We have used Monte Carlo simulations for a two-layered diffusive medium to investigate the effect of a superficial layer on the measurement of absorption variations from optical diffuse reflectance data processed by using: (a) a multidistance, frequency-domain method based on diffusion theory for a semi-infinite homogeneous medium; (b) a differential-pathlength-factor method based on a modified Lambert-Beer law for a homogeneous medium and (c) a two-distance, partial-pathlength method based on a modified Lambert-Beer law for a two-layered medium. Methods (a) and (b) lead to a single value for the absorption variation, whereas method (c) yields absorption variations for each layer. In the simulations, the optical coefficients of the medium were representative of those of biological tissue in the near-infrared. The thickness of the first layer was in the range 0.3-1.4 cm, and the source-detector distances were in the range 1-5 cm, which is typical of near-infrared diffuse reflectance measurements in tissue. The simulations have shown that (1) method (a) is mostly sensitive to absorption changes in the underlying layer, provided that the thickness of the superficial layer is {approx}0.6 cm or less; (2) method (b) is significantly affected by absorption changes in the superficial layer and (3) method (c) yields the absorption changes for both layers with a relatively good accuracy of {approx}4% for the superficial layer and {approx}10% for the underlying layer (provided that the absorption changes are less than 20-30% of the baseline value). We have applied all three methods of data analysis to near-infrared data collected on the forehead of a human subject during electroconvulsive therapy. Our results suggest that the multidistance method (a) and the two-distance partial-pathlength method (c) may better decouple the contributions to the optical signals that originate in deeper tissue (brain) from those that originate in more superficial tissue layers.

  17. Boiling heat transfer characteristics of fatty acid methyl ester(FAME)in falling film evaporator%脂肪酸甲酯降膜蒸发器沸腾传热性能

    Institute of Scientific and Technical Information of China (English)

    徐委托; 马晓建; 马力; 陈俊英; 杨闪; 张芬芬

    2016-01-01

    利用传统的多管排列式蒸发器对高黏度、易结垢的混合物进行蒸发,容易造成布液器堵塞,且结垢后的传热管难以清理。因此根据物料特性,本文设计了一种新型的降膜蒸发器,采用大降液孔加倾斜环板进行布膜,利用内径较大的锥筒作为传热壁面,并以粗甲酯作为试验工质对蒸发器的降膜蒸发传热系数随蒸发器筒体半锥度角、液膜流动雷诺数以及输入热通量之间的关系进行了试验研究。结果表明:该型蒸发器对于上述工质具有较好的适用性,蒸发系统能够在保持较高的传热系数的条件下,连续运行而不发生堵塞;蒸发器筒体锥度角有效地强化了降膜蒸发传热过程,而较大的热通量及进料流量在一定程度上却不利于蒸发传热。最后建立了降膜蒸发传热系数随蒸发器筒体半锥角和流动准数之间的经验关联式。%Using conventional line-tube heat exchanger for evaporation of high viscosity and easy-to-scaling mixture can easily block liquid distributor and make the cleaning of foul tube impossible. Therefore,a new type of falling film evaporator was designed,which used large liquid orifice plus tilt ring plate for liquid distribution and took larger diameter of conical shell as heat transfer wall. The variation of boiling heat transfer coefficients with shell’s taper angle,Reynolds number and heat fluxes were determined by a pilot scale falling film evaporation system,using the FAME mixture as liquid model. Result showed that this type of evaporator worked well for FAME,the system could work smoothly with high heat transfer efficiency for a long time and without the occurrence of clogging. The evaporator shell’s taper angle can intensify heat transfer process. The increase of heat flux and feed flow had a negative influence on heat transfer coefficient. Experimental correlation for boiling heat transfer coefficients with consideration of

  18. Experimental Study on Pressure Drop of Falling Film Flow Across Tube Bundles in Rotated Square Arrangement%转角正方形管束有降膜流动时的压降实验

    Institute of Scientific and Technical Information of China (English)

    刘华; 沈胜强; 陈石; 龚路远; 刘瑞; 陈学

    2013-01-01

    To study the effects of flow resistance in large-scale seawater desalination facility on the performance itself,an experimental setup was built to simulate the steam flow process in a horizontal-tube falling film evaporator,so as to analyze the influence of saturated steam temperature and spray density on the flow resistance in the tube bundle.The new parameter (Reynolds number of spray water) was used to fit the experimental results,and subsequently a pressure drop coefficient formula was obtained for the steam flow across the tube bundle in rotated square arrangement.Results show that for a constant steam flow and spray density,the pressure drop reduces with rising saturated steam temperature,and the error of differential pressure is within-± 15% between predicted value and actual measurement.%为了深入研究大型海水淡化装置中流动阻力对装置性能的影响,建立了大型水平管束降膜流动特性实验台,模拟了水平管降膜蒸发器内蒸汽的流动过程,分析了饱和蒸汽温度和喷淋密度对管束流动阻力的影响,引入新的参数(喷淋雷诺数)对实验数据进行了拟合,得出蒸汽横掠有降膜流动的转角正方形管束的压降系数公式.结果表明:在相同的蒸汽质量流量和喷淋密度下,压降随饱和蒸汽温度的升高而降低;压差预测值与实验值的误差小于±15%.

  19. 多效降膜式蒸发器换热面积分配原则%Heat Transfer Area Allocation Principles of Multi-Effect Falling Film Evaporator

    Institute of Scientific and Technical Information of China (English)

    刘殿宇

    2014-01-01

    The heat exchange area of different effect of multi-effect falling film evaporator the effect is determined according to the material and heat balance, and the allocation of effective temperature difference in different effect via heat balance calculation determines the size of the heat exchange area. Effect of increased material concentration and boiling point during the process of evaporation often lead to the increases of effect area. Material at the end of effect is also facing the problem of insufficient wetting around the tube. To cut down effect hear exchange area will no doubt solve the above problem and reduce scaling and coking. This paper illustrates how to allocate effective heat difference to different effect.%多效降膜式蒸发器各效换热面积是依据物料及热量衡算确定的,而热量衡算中的有效温差在各效的分配决定了换热面积的大小。随着蒸发的进行物料浓度的提高和沸点升高的影响,对有些物料影响明显,往往导致末效面积增大,物料到了末效还面临降膜管周边润湿量不足的问题,对并流加料末效出料的多效来说,减小末效换热面积无疑可以起到增大降膜管周边润湿量减缓结垢结焦的的发生,就此进行阐述如何分配各效有效温差。

  20. Thermal properties of composite two-layer systems with a fractal inclusion structure

    Science.gov (United States)

    Reyes-Salgado, J. J.; Dossetti, V.; Bonilla-Capilla, B.; Carrillo, J. L.

    2015-01-01

    In this work, we study the thermal transport properties of platelike composite two-layer samples made of polyester resin and magnetite inclusions. By means of photoacoustic spectroscopy and thermal relaxation, their effective thermal diffusivity and conductivity were experimentally measured. The composite layers were prepared under the action of a static magnetic field, resulting in anisotropic (fractal) inclusion structures with the formation of chain-like magnetite aggregates parallel to the faces of the layers. In one kind of the bilayers, a composite layer was formed on top of a resin layer while their relative thickness was varied. These samples can be described by known models. In contrast, bilayers with the same concentration of inclusions and the same thickness on both sides, where only the angle between their inclusion structures was systematically varied, show a nontrivial behaviour of their thermal conductivity as a function of this angle. Through a multifractal and lacunarity analysis, we explain the observed thermal response in terms of the complexity of the interface between the layers.

  1. Two layer asymptotic model for the wave propagation in the presence of vorticity

    Science.gov (United States)

    Kazakova, M. Yu; Noble, P.

    2016-06-01

    In the present study, we consider the system of two layers of the immiscible constant density fluids which are modeled by the full Euler equations. The domain of the flow is infinite in the horizontal directions and delimited above by a free surface. Bottom topography is taken into account. This is a simple model of the wave propagation in the ocean where the upper layer corresponds to the (thin) layer of fluid above the thermocline whereas the lower layer is under the thermocline. Though even this simple framework is computationally too expensive and mathematically too complicated to describe efficiently propagation of waves in the ocean. Modeling assumption such as shallowness, vanishing vorticity and hydrostatic pressure are usually made to get the bi-layer shallow water models that are mathematically more manageable. Though, they cannot describe correctly the propagation of both internal and free surface waves and dispersive/non hydrostatic must be added. Our goal is to consider the regime of medium to large vorticities in shallow water flow. We present the derivation of the model for internal and surface wave propagation in the case of constant and general vorticities in each layer. The model reduces to the classical Green-Naghdi equations in the case of vanishing vorticities.

  2. Two-layer interfacial flows beyond the Boussinesq approximation: a Hamiltonian approach

    CERN Document Server

    Camassa, R; Ortenzi, G

    2015-01-01

    The theory of integrable systems of Hamiltonian PDEs and their near-integrable deformations is used to study evolution equations resulting from vertical-averages of the Euler system for two-layer stratified flows in an infinite 2D channel. The Hamiltonian structure of the averaged equations is obtained directly from that of the Euler equations through the process of Hamiltonian reduction. Long-wave asymptotics together with the Boussinesq approximation of neglecting the fluids' inertia is then applied to reduce the leading order vertically averaged equations to the shallow-water Airy system, and thence, in a non-trivial way, to the dispersionless non-linear Schr\\"odinger equation. The full non-Boussinesq system for the dispersionless limit can then be viewed as a deformation of this well known equation. In a perturbative study of this deformation, it is shown that at first order the deformed system possesses an infinite sequence of constants of the motion, thus casting this system within the framework of comp...

  3. Method of the Moulding Sands Binding Power Assessment in Two-Layer Moulds Systems

    Directory of Open Access Journals (Sweden)

    M. Holtzer

    2014-07-01

    Full Text Available More and more foundry plants applying moulding sands with water-glass or its substitutes for obtaining the high-quality casting surface at the smallest costs, consider the possibility of implementing two-layer moulds, in which e.g. the facing sand is a sand with an organic binder (no-bake type and the backing sand is a sand with inorganic binder. Both kinds of sands must have the same chemical reaction. The most often applied system is the moulding sand on the water-glass or geopolymer bases - as the backing sand and the moulding sand from the group of self-hardening sands with a resol resin - as the facing sand. Investigations were performed for the system: moulding sand with inorganic GEOPOL binder or moulding sand with water glass (as a backing sand and moulding sand, no-bake type, with a resol resin originated from various producers: Rezolit AM, Estrofen, Avenol NB 700 (as a facing sand. The LUZ apparatus, produced by Multiserw Morek, was adapted for investigations. A special partition with cuts was mounted in the attachment for making test specimens for measuring the tensile strength. This partition allowed a simultaneous compaction of two kinds of moulding sands. After 24 hours of hardening the highest values were obtained for the system: Geopol binder - Avenol resin.

  4. Display of the β-effect in the Black Sea Two-Layer Model

    Directory of Open Access Journals (Sweden)

    A.A. Pavlushin

    2016-10-01

    Full Text Available The research is a continuation of a series of numerical experiments on modeling formation of wind currents and eddies in the Black Sea within the framework of a two-layer eddy-resolving model. The main attention is focused on studying the β-effect role. The stationary cyclonic wind is used as an external forcing and the bottom topography is not considered. It is shown that at the β-effect being taken into account, the Rossby waves propagating from east to west are observed both during the currents’ formation and at the statistical equilibrium mode when the mesoscale eddies are formed. In the integral flows’ field the waves are visually manifested in a form of the alternate large-scale cyclonic gyres and zones in which the meso-scale anti-cyclones are formed. This spatial pattern constantly propagates to the west that differs from the results of calculations using the constant Coriolis parameter when the spatially alternate cyclonic and anti-cyclonic vortices are formed, but hold a quasi-stationary position. The waves with the parameters of the Rossby wave first barotropic mode for the closed basin are most clearly pronounced. Interaction of the Rossby waves with large-scale circulation results in intensification of the of the currents’ hydrodynamic instability and in formation of the mesoscale eddies. Significant decrease of kinetic and available potential energy as compared to the values obtained at the constant Coriolis parameter is also a consequence of the eddy formation intensification.

  5. Inferring topologies via driving-based generalized synchronization of two-layer networks

    Science.gov (United States)

    Wang, Yingfei; Wu, Xiaoqun; Feng, Hui; Lu, Jun-an; Xu, Yuhua

    2016-05-01

    The interaction topology among the constituents of a complex network plays a crucial role in the network’s evolutionary mechanisms and functional behaviors. However, some network topologies are usually unknown or uncertain. Meanwhile, coupling delays are ubiquitous in various man-made and natural networks. Hence, it is necessary to gain knowledge of the whole or partial topology of a complex dynamical network by taking into consideration communication delay. In this paper, topology identification of complex dynamical networks is investigated via generalized synchronization of a two-layer network. Particularly, based on the LaSalle-type invariance principle of stochastic differential delay equations, an adaptive control technique is proposed by constructing an auxiliary layer and designing proper control input and updating laws so that the unknown topology can be recovered upon successful generalized synchronization. Numerical simulations are provided to illustrate the effectiveness of the proposed method. The technique provides a certain theoretical basis for topology inference of complex networks. In particular, when the considered network is composed of systems with high-dimension or complicated dynamics, a simpler response layer can be constructed, which is conducive to circuit design. Moreover, it is practical to take into consideration perturbations caused by control input. Finally, the method is applicable to infer topology of a subnetwork embedded within a complex system and locate hidden sources. We hope the results can provide basic insight into further research endeavors on understanding practical and economical topology inference of networks.

  6. Extreme events statistics in a two-layer quasi-geostrophic atmospheric model

    Science.gov (United States)

    Galfi, Vera Melinda; Bodai, Tamas; Lucarini, Valerio

    2016-04-01

    Extreme events statistics provides a theoretical framework to analyze and predict extreme events based on the convergence of the distribution of the extremes to some limiting distribution. In this work we analyze the convergence of the distribution of extreme events to the Generalized Extreme Value (GEV) distribution and to the Generalized Pareto Distribution (GPD), using a two-layer quasi-geostrophic atmospheric model, and compare our results with theoretical findings from the field of extreme value theory for dynamical systems. We study the behavior of the GEV shape parameter by increasing the block size and of the GPD shape parameter by increasing the threshold, and compare the inferred parameters with a theoretical shape parameter that depends only on the geometrical properties of the attractor. The main objective is to find out whether this theoretical shape parameter can be used to evaluate extreme event analysis based on model output. For this, we perform very long simulations. We run our system with two different levels of forcing determined by two different meridional temperature gradients, one inducing a medium level of chaos and the other one a high level of chaos. We analyze in both cases extremes of energy variables.

  7. Deposition, Heat Treatment And Characterization of Two Layer Bioactive Coatings on Cylindrical PEEK.

    Science.gov (United States)

    Durham, John W; Rabiei, Afsaneh

    2016-09-15

    Polyether ether ketone (PEEK) rods were coated via ion beam asssited deposition (IBAD) at room temperature. The coating consists of a two-layer design of yttria-stabilized zirconia (YSZ) as a heat-protection layer, and hydroxyapatite (HA) as a top layer to increase bioactivity. A rotating substrate holder was designed to deposit an even coating on the cylindrical surface of PEEK rods; the uniformity is verified by cross-sectional measurements using scanning electron microscopy (SEM). Deposition is followed by heat treatment of the coating using microwave annealing and autoclaving. Transmission electron microscopy (TEM) showed a dense, uniform columnar grain structure in the YSZ layer that is well bonded to the PEEK substrate, while the calcium phosphate layer was amorphous and pore-free in its as-deposited state. Subsequent heat treatment via microwave energy introduced HA crystallization in the calcium phosphate layer and additional autoclaving further expanded the crystallization of the HA layer. Chemical composition evaluation of the coating indicated the Ca/P ratios of the HA layer to be near that of stoichiometric HA, with minor variations through the HA layer thickness. The adhesion strength of as-deposited HA/YSZ coatings on smooth, polished PEEK surfaces was mostly unaffected by microwave heat treatment, but decreased with additional autoclave treatment. Increasing surface roughness showed improvement of bond strength.

  8. A novel approach to ECG classification based upon two-layered HMMs in body sensor networks.

    Science.gov (United States)

    Liang, Wei; Zhang, Yinlong; Tan, Jindong; Li, Yang

    2014-03-27

    This paper presents a novel approach to ECG signal filtering and classification. Unlike the traditional techniques which aim at collecting and processing the ECG signals with the patient being still, lying in bed in hospitals, our proposed algorithm is intentionally designed for monitoring and classifying the patient's ECG signals in the free-living environment. The patients are equipped with wearable ambulatory devices the whole day, which facilitates the real-time heart attack detection. In ECG preprocessing, an integral-coefficient-band-stop (ICBS) filter is applied, which omits time-consuming floating-point computations. In addition, two-layered Hidden Markov Models (HMMs) are applied to achieve ECG feature extraction and classification. The periodic ECG waveforms are segmented into ISO intervals, P subwave, QRS complex and T subwave respectively in the first HMM layer where expert-annotation assisted Baum-Welch algorithm is utilized in HMM modeling. Then the corresponding interval features are selected and applied to categorize the ECG into normal type or abnormal type (PVC, APC) in the second HMM layer. For verifying the effectiveness of our algorithm on abnormal signal detection, we have developed an ECG body sensor network (BSN) platform, whereby real-time ECG signals are collected, transmitted, displayed and the corresponding classification outcomes are deduced and shown on the BSN screen.

  9. Dynamics and flow-coupling in two-layer turbulent thermal convection

    CERN Document Server

    Xie, Yi-Chao

    2015-01-01

    We present an experimental investigation of the dynamics and flow-coupling of convective turbulent flows in a cylindrical Rayleigh-Benard convection cell with two immiscible fluids, water and fluorinert FC-77 electronic liquid (FC77). It is found that one large-scale circulation (LSC) roll exists in each of the fluid layers, and that their circulation planes have two preferred azimuthal orientations separated by $\\sim\\pi$. A surprising finding of the study is that cessations/reversals of the LSC in FC77 of the two-layer system occur much more frequently than they do in single-layer turbulent RBC, and that a cessation is most likely to result in a flow reversal of the LSC, which is in sharp contrast with the uniform distribution of the orientational angular change of the LSC before and after cessations in single-layer turbulent RBC. This implies that the dynamics governing cessations and reversals in the two systems are very different. Two coupling modes, thermal coupling (flow directions of the two LSCs are o...

  10. MHD two-layered unsteady fluid flow and heat transfer through a horizontal channel between

    Directory of Open Access Journals (Sweden)

    Raju T. Linga

    2014-02-01

    Full Text Available An unsteady magnetohydrodynamic (MHD two-layered fluids flow and heat transfer in a horizontal channel between two parallel plates in the presence of an applied magnetic and electric field is investigated, when the whole system is rotated about an axis perpendicular to the flow. The flow is driven by a constant uniform pressure gradient in the channel bounded by two parallel insulating plates, when both fluids are considered as electrically conducting, incompressible with variable properties, viz. different viscosities, thermal and electrical conductivities. The transport properties of the two fluids are taken to be constant and the bounding plates are maintained at constant and equal temperatures. The governing partial differential equations are then reduced to the ordinary linear differential equations using two-term series. Closed form solutions for primary and secondary velocity, also temperature distributions are obtained in both the fluid regions of the channel. Profiles of these solutions are plotted to discuss the effects of the flow and heat transfer characteristics, and their dependence on the governing parameters involved, such as the Hartmann number, rotation parameter, ratios of the viscosities, heights, electrical and thermal conductivities

  11. A Two-Layer Method for Sedentary Behaviors Classification Using Smartphone and Bluetooth Beacons.

    Science.gov (United States)

    Cerón, Jesús D; López, Diego M; Hofmann, Christian

    2017-01-01

    Among the factors that outline the health of populations, person's lifestyle is the more important one. This work focuses on the caracterization and prevention of sedentary lifestyles. A sedentary behavior is defined as "any waking behavior characterized by an energy expenditure of 1.5 METs (Metabolic Equivalent) or less while in a sitting or reclining posture". To propose a method for sedentary behaviors classification using a smartphone and Bluetooth beacons considering different types of classification models: personal, hybrid or impersonal. Following the CRISP-DM methodology, a method based on a two-layer approach for the classification of sedentary behaviors is proposed. Using data collected from a smartphones' accelerometer, gyroscope and barometer; the first layer classifies between performing a sedentary behavior and not. The second layer of the method classifies the specific sedentary activity performed using only the smartphone's accelerometer and barometer data, but adding indoor location data, using Bluetooth Low Energy (BLE) beacons. To improve the precision of the classification, both layers implemented the Random Forest algorithm and the personal model. This study presents the first available method for the automatic classification of specific sedentary behaviors. The layered classification approach has the potential to improve processing, memory and energy consumption of mobile devices and wearables used.

  12. Long-time Behavior of a Two-layer Model of Baroclinic Quasi-geostrophic Turbulence

    CERN Document Server

    Farhat, Aseel; Titi, Edriss S; Ziane, Mohammed

    2012-01-01

    We study a viscous two-layer quasi-geostrophic beta-plane model that is forced by imposition of a spatially uniform vertical shear in the eastward (zonal) component of the layer flows, or equivalently a spatially uniform north-south temperature gradient. We prove that the model is linearly unstable, but that non-linear solutions are bounded in time by a bound which is independent of the initial data and is determined only by the physical parameters of the model. We further prove, using arguments first presented in the study of the Kuramoto-Sivashinsky equation, the existence of an absorbing ball in appropriate function spaces, and in fact the existence of a compact finite-dimensional attractor, and provide upper bounds for the fractal and Hausdorff dimensions of the attractor. Finally, we show the existence of an inertial manifold for the dynamical system generated by the model's solution operator. Our results provide rigorous justification for observations made by Panetta based on long-time numerical integra...

  13. A two-layer $\\alpha\\omega$ dynamo model, and its implications for 1-D dynamos

    CERN Document Server

    Roald, C B

    1999-01-01

    I will discuss an attempt at representing an interface dynamo in a simplified, essentially 1D framework. The operation of the dynamo is broken up into two 1D layers, one containing the $\\alpha$ effect and the other containing the $\\omega$ effect, and these two layers are allowed to communicate with each other by the simplest possible representation of diffusion, an analogue of Newton's law of cooling. Dynamical back-reaction of the magnetic field on them with diagrams I computed for a comparable purely 1D model. The bifurcation structure shows remarkable similarity, but a couple of subtle changes imply dramatically different physical behaviour for the model. In particular, the solar-like dynamo mode found in the 1-layer model is not stable in the 2-layer version; instead there is an (apparent) homoclinic bifurcation and a sequence of periodic, quasiperiodic, and chaotic modes. I argue that the fragility of these models makes them effectively useless as predictors or interpreters of more complex dynamos.

  14. Two-Layer Linear MPC Approach Aimed at Walking Beam Billets Reheating Furnace Optimization

    Directory of Open Access Journals (Sweden)

    Silvia Maria Zanoli

    2017-01-01

    Full Text Available In this paper, the problem of the control and optimization of a walking beam billets reheating furnace located in an Italian steel plant is analyzed. An ad hoc Advanced Process Control framework has been developed, based on a two-layer linear Model Predictive Control architecture. This control block optimizes the steady and transient states of the considered process. Two main problems have been addressed. First, in order to manage all process conditions, a tailored module defines the process variables set to be included in the control problem. In particular, a unified approach for the selection on the control inputs to be used for control objectives related to the process outputs is guaranteed. The impact of the proposed method on the controller formulation is also detailed. Second, an innovative mathematical approach for stoichiometric ratios constraints handling has been proposed, together with their introduction in the controller optimization problems. The designed control system has been installed on a real plant, replacing operators’ mental model in the conduction of local PID controllers. After two years from the first startup, a strong energy efficiency improvement has been observed.

  15. A global-scale two-layer transient groundwater model: Development and application to groundwater depletion

    Science.gov (United States)

    de Graaf, Inge E. M.; van Beek, Rens L. P. H.; Gleeson, Tom; Moosdorf, Nils; Schmitz, Oliver; Sutanudjaja, Edwin H.; Bierkens, Marc F. P.

    2017-04-01

    Groundwater is the world's largest accessible source of freshwater to satisfy human water needs. Moreover, groundwater buffers variable precipitation rates over time, thereby effectively sustaining river flows in times of droughts and evaporation in areas with shallow water tables. In this study, building on previous work, we simulate groundwater head fluctuations and groundwater storage changes in both confined and unconfined aquifer systems using a global-scale high-resolution (5‧) groundwater model by deriving new estimates of the distribution and thickness of confining layers. Inclusion of confined aquifer systems (estimated 6-20% of the total aquifer area) improves estimates of timing and amplitude of groundwater head fluctuations and changes groundwater flow paths and groundwater-surface water interaction rates. Groundwater flow paths within confining layers are shorter than paths in the underlying aquifer, while flows within the confined aquifer can get disconnected from the local drainage system due to the low conductivity of the confining layer. Lateral groundwater flows between basins are significant in the model, especially for areas with (partially) confined aquifers were long flow paths crossing catchment boundaries are simulated, thereby supporting water budgets of neighboring catchments or aquifer systems. The developed two-layer transient groundwater model is used to identify hot-spots of groundwater depletion. Global groundwater depletion is estimated as 7013 km3 (137 km3y-1) over 1960-2010, which is consistent with estimates of previous studies.

  16. A Novel Approach to ECG Classification Based upon Two-Layered HMMs in Body Sensor Networks

    Directory of Open Access Journals (Sweden)

    Wei Liang

    2014-03-01

    Full Text Available This paper presents a novel approach to ECG signal filtering and classification. Unlike the traditional techniques which aim at collecting and processing the ECG signals with the patient being still, lying in bed in hospitals, our proposed algorithm is intentionally designed for monitoring and classifying the patient’s ECG signals in the free-living environment. The patients are equipped with wearable ambulatory devices the whole day, which facilitates the real-time heart attack detection. In ECG preprocessing, an integral-coefficient-band-stop (ICBS filter is applied, which omits time-consuming floating-point computations. In addition, two-layered Hidden Markov Models (HMMs are applied to achieve ECG feature extraction and classification. The periodic ECG waveforms are segmented into ISO intervals, P subwave, QRS complex and T subwave respectively in the first HMM layer where expert-annotation assisted Baum-Welch algorithm is utilized in HMM modeling. Then the corresponding interval features are selected and applied to categorize the ECG into normal type or abnormal type (PVC, APC in the second HMM layer. For verifying the effectiveness of our algorithm on abnormal signal detection, we have developed an ECG body sensor network (BSN platform, whereby real-time ECG signals are collected, transmitted, displayed and the corresponding classification outcomes are deduced and shown on the BSN screen.

  17. A two-layer recurrent neural network for nonsmooth convex optimization problems.

    Science.gov (United States)

    Qin, Sitian; Xue, Xiaoping

    2015-06-01

    In this paper, a two-layer recurrent neural network is proposed to solve the nonsmooth convex optimization problem subject to convex inequality and linear equality constraints. Compared with existing neural network models, the proposed neural network has a low model complexity and avoids penalty parameters. It is proved that from any initial point, the state of the proposed neural network reaches the equality feasible region in finite time and stays there thereafter. Moreover, the state is unique if the initial point lies in the equality feasible region. The equilibrium point set of the proposed neural network is proved to be equivalent to the Karush-Kuhn-Tucker optimality set of the original optimization problem. It is further proved that the equilibrium point of the proposed neural network is stable in the sense of Lyapunov. Moreover, from any initial point, the state is proved to be convergent to an equilibrium point of the proposed neural network. Finally, as applications, the proposed neural network is used to solve nonlinear convex programming with linear constraints and L1 -norm minimization problems.

  18. Convergence of Extreme Value Statistics in a Two-Layer Quasi-Geostrophic Atmospheric Model

    Directory of Open Access Journals (Sweden)

    Vera Melinda Gálfi

    2017-01-01

    Full Text Available We search for the signature of universal properties of extreme events, theoretically predicted for Axiom A flows, in a chaotic and high-dimensional dynamical system. We study the convergence of GEV (Generalized Extreme Value and GP (Generalized Pareto shape parameter estimates to the theoretical value, which is expressed in terms of the partial information dimensions of the attractor. We consider a two-layer quasi-geostrophic atmospheric model of the mid-latitudes, adopt two levels of forcing, and analyse the extremes of different types of physical observables (local energy, zonally averaged energy, and globally averaged energy. We find good agreement in the shape parameter estimates with the theory only in the case of more intense forcing, corresponding to a strong chaotic behaviour, for some observables (the local energy at every latitude. Due to the limited (though very large data size and to the presence of serial correlations, it is difficult to obtain robust statistics of extremes in the case of the other observables. In the case of weak forcing, which leads to weaker chaotic conditions with regime behaviour, we find, unsurprisingly, worse agreement with the theory developed for Axiom A flows.

  19. Critical properties of XY model on two-layer Villain-ferromagnetic lattice

    Institute of Scientific and Technical Information of China (English)

    Wang Yi; R. Quartu; Liu Xiao-Yan; Han Ru-Qi; Horiguchi Tsuyoshi

    2004-01-01

    We investigate phase transitions of the XY model on a two-layer square lattice which consists of a Villain plane(J) and a ferromagnetic plane (I), using Monte Carlo simulations and a histogram method. Depending on the values of interaction parameters (I, J), the system presents three phases: namely, a Kosterlitz-Thouless (KT) phase in which the two planes are critical for I predominant over J, a chiral phase in which the two planes have a chiral order for J predominant over I and a new phase in which only the Villain plane has a chiral order and the ferromagnetic plane is paramagnetic with a small value of chirality. We clarify the nature of phase transitions by using a finite size scaling method. We find three different kinds of transitions according to the values of (I, J): the KT transition, the Ising transition and an XY-Ising transition with v = 0.849(3). It turns out that the Ising or XY-Ising transition is associated with the disappearance of the chiral order in the Villain plane.

  20. Powerful Amplification Cascades of FRET-Based Two-Layer Nonenzymatic Nucleic Acid Circuits.

    Science.gov (United States)

    Quan, Ke; Huang, Jin; Yang, Xiaohai; Yang, Yanjing; Ying, Le; Wang, He; Xie, Nuli; Ou, Min; Wang, Kemin

    2016-06-07

    Nucleic acid circuits have played important roles in biological engineering and have increasingly attracted researchers' attention. They are primarily based on nucleic acid hybridizations and strand displacement reactions between nucleic acid probes of different lengths. Signal amplification schemes that do not rely on protein enzyme show great potential in analytical applications. While the single amplification circuit often achieves linear amplification that may not meet the need for detection of target in a very small amount, it is very necessary to construct cascade circuits that allow for larger amplification of inputs. Herein, we have successfully engineered powerful amplification cascades of FRET-based two-layer nonenzymatic nucleic acid circuits, in which the outputs of catalyzed hairpin assembly (CHA) activate hybridization chain reactions (HCR) circuits to induce repeated hybridization, allowing real-time monitoring of self-assembly process by FRET signal. The cascades can yield 50000-fold signal amplification with the help of the well-designed and high-quality nucleic acid circuit amplifiers. Subsequently, with coupling of structure-switching aptamer, as low as 200 pM adenosine is detected in buffer, as well as in human serum. To our knowledge, we have for the first time realized real-time monitoring adaptation of HCR to CHA circuits and achieved amplified detection of nucleic acids and small molecules with relatively high sensitivity.

  1. The Patient Who Falls

    Science.gov (United States)

    Tinetti, Mary E.; Kumar, Chandrika

    2013-01-01

    Falls are common health events that cause discomfort and disability for older adults and stress for caregivers. Using the case of an older man who has experienced multiple falls and a hip fracture, this article, which focuses on community-living older adults, addresses the consequences and etiology of falls; summarizes the evidence on predisposing factors and effective interventions; and discusses how to translate this evidence into patient care. Previous falls; strength, gait, and balance impairments; and medications are the strongest risk factors for falling. Effective single interventions include exercise and physical therapy, cataract surgery, and medication reduction. Evidence suggests that the most effective strategy for reducing the rate of falling in community-living older adults may be intervening on multiple risk factors. Vitamin D has the strongest clinical trial evidence of benefit for preventing fractures among older men at risk. Issues involved in incorporating these evidence-based fall prevention interventions into outpatient practice are discussed, as are the trade-offs inherent in managing older patients at risk of falling. While challenges and barriers exist, fall prevention strategies can be incorporated into clinical practice. PMID:20085954

  2. Dependences of optical properties of spherical two-layered nanoparticles on parameters of gold core and material shell

    Science.gov (United States)

    Pustovalov, V. K.; Astafyeva, L. G.; Zharov, V. P.

    2013-12-01

    Modeling of nonlinear dependences of optical properties of spherical two-layered gold core and some material shell nanoparticles (NPs) placed in water on parameters of core and shell was carried out on the basis of the extended Mie theory. Efficiency cross-sections of absorption, scattering and extinction of radiation with wavelength 532 nm by core-shell NPs in the ranges of core radii r00=5-40 nm and of relative NP radii r1/r00=1-8 were calculated (r1-radius of two-layered nanoparticle). Shell materials were used with optical indexes in the ranges of refraction n1=0.2-1.5 and absorption k1=0-3.5 for the presentation of optical properties of wide classes of shell materials (including dielectrics, metals, polymers, vapor shell around gold core). Results show nonlinear dependences of optical properties of two-layered NPs on optical indexes of shell material, core r00 and relative NP r1/r00 radii. Regions with sharp decrease and increase of absorption, scattering and extinction efficiency cross-sections with changing of core and shell parameters were investigated. These dependences should be taken into account for applications of two-layered NPs in laser nanomedicine and optical diagnostics of tissues. The results can be used for experimental investigation of shell formation on NP core and optical determination of geometrical parameters of core and shell of two-layered NPs.

  3. THE SEMI-GEOSTROPHIC ADAPTATION PROCESS WITH TWO-LAYER BAROCLINIC MODEL IN LOW LATITUDE ATMOSPHERE

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper, the adaptation process in low latitude atmosphere is discussed by means of a two-layer baroclinic model on the equator β plane, showing that the adaptation process in low latitude is mainly dominated by the internal inertial gravity waves. The initial ageostrophic energy is dispersed by the internal inertial gravity waves, and as a result, the geostrophic motion is obtained in zonal direction while the ageostrophic motion maintains in meridional direction, which can be called semi-geostrophic balance in barotropic model as well as semi-thermal-wind balance in baroclinic model. The vertical motion is determined both by the distribution of the initial vertical motion and that of the initial vertical motion tendency, but it is unrelated to the initial potential vorticity. Finally, the motion tends to be horizontal. The discussion of the physical mechanism of the semi-thermal-wind balance in low latitude atmosphere shows that the achievement of the semi-thermal-wind balance is due to the adjustment between the stream field and the temperature field through the horizontal convergence and divergence which is related to the vertical motion excited by the internal inertial gravity waves. The terminal adaptation state obtained shows that the adaptation direction between the mean temperature field and the shear flow field is determined by the ratio of the scale of the initial ageostrophic disturbance to the scale of one character scale related to the baroclinic Rossby radius of deformation. The shear stream field adapts to the mean temperature field when the ratio is greater than 1, and the mean temperature field adapts to the shear stream field when the ratio is smaller than 1.

  4. Convective instability in a two-layer system of reacting fluids with concentration-dependent diffusion

    Science.gov (United States)

    Aitova, E. V.; Bratsun, D. A.; Kostarev, K. G.; Mizev, A. I.; Mosheva, E. A.

    2016-12-01

    The development of convective instability in a two-layer system of miscible fluids placed in a narrow vertical gap has been studied theoretically and experimentally. The upper and lower layers are formed with aqueous solutions of acid and base, respectively. When the layers are brought into contact, the frontal neutralization reaction begins. We have found experimentally a new type of convective instability, which is characterized by the spatial localization and the periodicity of the structure observed for the first time in the miscible systems. We have tested a number of different acid-base systems and have found a similar patterning there. In our opinion, it may indicate that the discovered effect is of a general nature and should be taken into account in reaction-diffusion-convection problems as another tool with which the reaction can govern the movement of the reacting fluids. We have shown that, at least in one case (aqueous solutions of nitric acid and sodium hydroxide), a new type of instability called as the concentration-dependent diffusion convection is responsible for the onset of the fluid flow. It arises when the diffusion coefficients of species are different and depend on their concentrations. This type of instability can be attributed to a variety of double-diffusion convection. A mathematical model of the new phenomenon has been developed using the system of reaction-diffusion-convection equations written in the Hele-Shaw approximation. It is shown that the instability can be reproduced in the numerical experiment if only one takes into account the concentration dependence of the diffusion coefficients of the reagents. The dynamics of the base state, its linear stability and nonlinear development of the instability are presented. It is also shown that by varying the concentration of acid in the upper layer one can achieve the occurrence of chemo-convective solitary cell in the bulk of an almost immobile fluid. Good agreement between the

  5. Global chaotization of fluid particle trajectories in a sheared two-layer two-vortex flow

    Energy Technology Data Exchange (ETDEWEB)

    Ryzhov, Evgeny A., E-mail: ryzhovea@poi.dvo.ru [Pacific Oceanological Institute of FEB RAS, 43, Baltiyskaya Street, Vladivostok 690041 (Russian Federation); Koshel, Konstantin V., E-mail: kvkoshel@poi.dvo.ru [Pacific Oceanological Institute of FEB RAS, 43, Baltiyskaya Street, Vladivostok 690041 (Russian Federation); Far Eastern Federal University, 8, Sukhanova Street, Vladivostok 690950 (Russian Federation)

    2015-10-15

    In a two-layer quasi-geostrophic approximation, we study the irregular dynamics of fluid particles arising due to two interacting point vortices embedded in a deformation flow consisting of shear and rotational components. The two vortices are arranged within the bottom layer, but an emphasis is on the upper-layer fluid particle motion. Vortices moving in one layer induce stirring of passive scalars in the other layer. This is of interest since point vortices induce singular velocity fields in the layer they belong to; however, in the other layer, they induce regular velocity fields that generally result in a change in passive particle stirring. If the vortices are located at stagnation points, there are three different types of the fluid flow. We examine how properties of each flow configuration are modified if the vortices are displaced from the stagnation points and thus circulate in the immediate vicinity of these points. To that end, an analysis of the steady-state configurations is presented with an emphasis on the frequencies of fluid particle oscillations about the elliptic stagnation points. Asymptotic relations for the vortex and fluid particle zero–oscillation frequencies are derived in the vicinity of the corresponding elliptic points. By comparing the frequencies of fluid particles with the ones of the vortices, relations between the parameters that lead to enhanced stirring of fluid particles are established. It is also demonstrated that, if the central critical point is elliptic, then the fluid particle trajectories in its immediate vicinity are mostly stable making it harder for the vortex perturbation to induce stirring. Change in the type of the central point to a hyperbolic one enhances drastically the size of the chaotic dynamics region. Conditions on the type of the central critical point also ensue from the derived asymptotic relations.

  6. Fall Leaf Portraits

    Science.gov (United States)

    O'Hara, Cristina

    2012-01-01

    In this article, the author describes how students can create a stunning as well as economical mosaic utilizing fall's brilliantly colored leaves, preserved at their peak in color. Start by choosing a beautiful fall day to take students on a nature walk to collect a variety of leaves in different shapes, sizes, and colors. Focus on collecting a…

  7. Falls and comorbidity

    DEFF Research Database (Denmark)

    Jørgensen, Terese Sara Høj; Hansen, Annette Højmann; Sahlberg, Marie

    2014-01-01

    AIMS: To compare nationwide time trends and mortality in hip and proximal humeral fractures; to explore associations between incidences of falls risk related comorbidities (FRICs) and incidence of fractures. METHODS: The study is a retrospective cohort study using nationwide Danish administrative....... CONCLUSIONS: The results suggest that the overall reduction in fractures can be explained by reduction in falls related comorbidity....

  8. An operational two-layer remote sensing model to estimate surface flux in regional scale: Physical background

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Renhua; SUN; Xiaomin; WANG; Weimin; XU; Jinping; ZH

    2005-01-01

    Based on the improved interaction mechanism of two-layer model, this paper proposed Pixel Component Arranging and Comparing Algorithm (PCACA) and theoretically positioning algorithm, estimated the true temperature of mixed pixel in four extreme points in combination with the measurements of dry and wet points in calibration fields and improved the reliability of positioning dry and wet line. A new two-layer energy-separation algorithm was proposed,which was simple and direct without resistance network parameters for each pixel. We also proposed a new thought about the effect of advection. The albedo of mixed pixel was also separated with PCACA. In combination with two-layer energy-separation algorithm, the net radiation of mixed pixel was separated to overcome the uncertainty of conventional energy-separation algorithm using Beer's Law. Through the validation of retrieval result, this method is proved to be feasible and operational. At the same time, the uncertainty of this algorithm was objectively analyzed.

  9. Fall prevention conceptual framework.

    Science.gov (United States)

    Abraham, Sam

    2011-01-01

    Falls can have lasting psychological and physical consequences, particularly fractures and slow-healing processes, and patients may also lose confidence in walking. Injuries from falls lead to functional decline, institutionalization, higher health care costs, and decreased quality of life. The process related to the problem of patient falls in the hospital, using the nursing model developed by the theorist, Ida Jean Orlando, is explained in this article. The useful tool that provides guidance to marketers in this endeavor is Maslow's hierarchy of needs. During acute illness, individuals are greatly in need of satisfying their physiological needs. If these needs are not met, patients leave the hospital lacking a positive experience. Initial fall risk assessment is critical to plan intervention and individualize care plan. Interventions depend on the severity of fall risk factors.

  10. 中高温水平管降膜蒸发海水淡化研究%Research on Horizontal Tube Falling Film Evaporation for Seawater Desalination under Medium/High Temperature Conditions

    Institute of Scientific and Technical Information of China (English)

    于开录; 吕庆春; 谢峰; 阮国岭; 朱春来; 李海平

    2011-01-01

    Aimed at the disadvantages of low heat transfer coefficient and high water production cost in low temperature multi-effect distillation seawater desalination, the horizontal tube falling film evaporation for seawater desalination under medium/high temperature conditions was studied.The influence of seawater evaporation temperature, seawater spray load and heat transfer temperature difference on heat transfer performance and scale formation was investigated.It is found that the increasing of seawater evaporation temperature and the decreasing of heat transfer temperature difference can increase the heat transfer coefficient of seawater desalination.The insufficiency and inhomogeneity of seawater spray amount are the main reasons causing scale formation on horizontal heat exchange tubes.The scale products are mainly calcium carbonate which can be chemically removed, as well as a little calcium sulfate which can only be produced at 90 ℃.%针对低温多效蒸馏海水淡化技术存在传热系数低、制水成本相对较高等缺点,开展了中高温条件下水平管降膜蒸发海水淡化的研究,考察了海水蒸发温度、海水喷淋负荷和传热温差等因素对海水淡化过程中传热性能和结垢情况的影响.结果表明,提高海水蒸发温度、降低传热温差可以增大海水淡化传热系数;海水喷淋量不足和不均是导致换热管结垢的主要原因,结垢产物主要为可化学清洗的碳酸钙,在蒸发温度为90℃时还产生了少量的硫酸钙.

  11. Electromagnetic fields due to a horizontal electric dipole antenna laid on the surface of a two-layer medium

    Science.gov (United States)

    Tsang, L.; Kong, J. A.

    1974-01-01

    With applications to geophysical subsurface probings, electromagnetic fields due to a horizontal electric dipole laid on the surface of a two-layer medium are solved by a combination of analytic and numerical methods. Interference patterns are calculated for various layer thickness. The results are interpreted in terms of normal modes, and the accuracies of the methods are discussed.

  12. Screen-Capturing System with Two-Layer Display for PowerPoint Presentation to Enhance Classroom Education

    Science.gov (United States)

    Lai, Yen-Shou; Tsai, Hung-Hsu; Yu, Pao-Ta

    2011-01-01

    This paper proposes a new presentation system integrating a Microsoft PowerPoint presentation in a two-layer method, called the TL system, to promote learning in a physical classroom. With the TL system, teachers can readily control hints or annotations as a way of making them visible or invisible to students so as to reduce information load. In…

  13. Hamiltonian Particle-Mesh Method for Two-Layer Shallow-Water Equations Subject to the Rigid-Lid Approximation

    NARCIS (Netherlands)

    Cotter, C.J.; Frank, J.E.; Reich, S.

    2004-01-01

    We develop a particle-mesh method for two-layer shallow-water equations subject to the rigid-lid approximation. The method is based on the recently proposed Hamiltonian particle-mesh (HPM) method and the interpretation of the rigid-lid approximation as a set of holonomic constraints. The suggested s

  14. Seneca Falls. Classroom Focus.

    Science.gov (United States)

    Balantic, Jeannette; Libresco, Andrea S.

    1995-01-01

    Presents a secondary school lesson based on the Seneca Falls Declaration of Sentiments. Provides lesson objectives and step-by-step instructional procedures. Includes quoted sections of the Declaration of Sentiments. (CFR)

  15. How does interference fall?

    CERN Document Server

    Orlando, Patrick J; Modi, Kavan

    2016-01-01

    We study how single- and double-slit interference patterns fall in the presence of gravity. First, we demonstrate that universality of free fall still holds in this case, i.e., interference patterns fall just like classical objects. Next, we explore lowest order relativistic effects in the Newtonian regime by employing a recent quantum formalism which treats mass as an operator. This leads to interactions between non-degenerate internal degrees of freedom (like spin in an external magnetic field) and external degrees of freedom (like position). Based on these effects, we present an unusual phenomenon, in which a falling double slit interference pattern periodically decoheres and recoheres. The oscillations in the visibility of this interference occur due to correlations built up between spin and position. Finally, we connect the interference visibility revivals with non-Markovian quantum dynamics.

  16. Fall Bottom Trawl Survey

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The standardized NEFSC Fall Bottom Trawl Survey was initiated in 1963 and covered an area from Hudson Canyon, NY to Nova Scotia, Canada. Throughout the years,...

  17. Editors' Fall Picks

    Science.gov (United States)

    Hoffert, Barbara; Heilbrun, Margaret; Kuzyk, Raya; Kim, Ann; McCormack, Heather; Katterjohn, Anna; Burns, Ann; Williams, Wilda

    2008-01-01

    From the fall's cascade of great new books, "Library Journal's" editors select their favorites--a dark rendition of Afghan life, a look at the "self-esteem trap," a celebration of Brooklyn activism, and much more.

  18. Flexible Touch Sensors Made of Two Layers of Printed Conductive Flexible Adhesives

    Directory of Open Access Journals (Sweden)

    Sungwon Seo

    2016-09-01

    Full Text Available Touch sensors are crucial in controlling robotic manipulation when a robot interacts with environmental objects. In this study, multilayer flexible touch sensors in the form of an array were developed. The sensors use ink-type conductive flexible adhesives as electrodes which were printed on polyethylene terephthalate (PET films in a parallel equidistance stripe pattern. Between the two printed layers, a double-sided adhesive film was used to combine each layer and was perforated at the junctions of the top and bottom electrodes with different-sized circles. These holes represent switching mechanisms between the top and bottom electrodes, and their sizes make the sensor respond to different levels of external pressure. We showed the durability of the fabricated sensor with 1 mm diameter holes by repeated experiments of exerting normal pressure ranging from 0 to 159.15 kPa for 1000 cycles. In case of 1 mm diameter holes, the state of each sensor node was reliably determined by the threshold pressures of 127.3 kPa for increasing pressure and 111.4 kPa for decreasing pressure. On the other hand, decreasing the hole size from 3 to 0.5 mm caused an increase in the threshold pressure from 1.41 to 214 kPa. The relation between the hole size and the threshold pressure was analyzed by a mechanical model. The sensor performance was also verified on curved surfaces up to 60 mm radius of curvatures. Additionally, we fabricated a sensor with three levels of sensitivity with a conventional method which was a thermal evaporation to show the extendibility of the idea.

  19. Flexible Touch Sensors Made of Two Layers of Printed Conductive Flexible Adhesives

    Science.gov (United States)

    Seo, Sungwon; Kim, Seonggi; Jung, Jiyeon; Ma, Rujun; Baik, Seunghyun; Moon, Hyungpil

    2016-01-01

    Touch sensors are crucial in controlling robotic manipulation when a robot interacts with environmental objects. In this study, multilayer flexible touch sensors in the form of an array were developed. The sensors use ink-type conductive flexible adhesives as electrodes which were printed on polyethylene terephthalate (PET) films in a parallel equidistance stripe pattern. Between the two printed layers, a double-sided adhesive film was used to combine each layer and was perforated at the junctions of the top and bottom electrodes with different-sized circles. These holes represent switching mechanisms between the top and bottom electrodes, and their sizes make the sensor respond to different levels of external pressure. We showed the durability of the fabricated sensor with 1 mm diameter holes by repeated experiments of exerting normal pressure ranging from 0 to 159.15 kPa for 1000 cycles. In case of 1 mm diameter holes, the state of each sensor node was reliably determined by the threshold pressures of 127.3 kPa for increasing pressure and 111.4 kPa for decreasing pressure. On the other hand, decreasing the hole size from 3 to 0.5 mm caused an increase in the threshold pressure from 1.41 to 214 kPa. The relation between the hole size and the threshold pressure was analyzed by a mechanical model. The sensor performance was also verified on curved surfaces up to 60 mm radius of curvatures. Additionally, we fabricated a sensor with three levels of sensitivity with a conventional method which was a thermal evaporation to show the extendibility of the idea. PMID:27649205

  20. Running interfacial waves in a two-layer fluid system subject to longitudinal vibrations

    Science.gov (United States)

    Goldobin, D. S.; Pimenova, A. V.; Kovalevskaya, K. V.; Lyubimov, D. V.; Lyubimova, T. P.

    2015-05-01

    We study the waves at the interface between two thin horizontal layers of immiscible fluids subject to high-frequency horizontal vibrations. Previously, the variational principle for energy functional, which can be adopted for treatment of quasistationary states of free interface in fluid dynamical systems subject to vibrations, revealed the existence of standing periodic waves and solitons in this system. However, this approach does not provide regular means for dealing with evolutionary problems: neither stability problems nor ones associated with propagating waves. In this work, we rigorously derive the evolution equations for long waves in the system, which turn out to be identical to the plus (or good) Boussinesq equation. With these equations one can find all the time-independent-profile solitary waves (standing solitons are a specific case of these propagating waves), which exist below the linear instability threshold; the standing and slow solitons are always unstable while fast solitons are stable. Depending on initial perturbations, unstable solitons either grow in an explosive manner, which means layer rupture in a finite time, or falls apart into stable solitons. The results are derived within the long-wave approximation as the linear stability analysis for the flat-interface state [D.V. Lyubimov and A.A. Cherepanov, Fluid Dynamics 21, 849 (1986)], 10.1007/BF02628017 reveals the instabilities of thin layers to be long wavelength.

  1. Running interfacial waves in a two-layer fluid system subject to longitudinal vibrations.

    Science.gov (United States)

    Goldobin, D S; Pimenova, A V; Kovalevskaya, K V; Lyubimov, D V; Lyubimova, T P

    2015-05-01

    We study the waves at the interface between two thin horizontal layers of immiscible fluids subject to high-frequency horizontal vibrations. Previously, the variational principle for energy functional, which can be adopted for treatment of quasistationary states of free interface in fluid dynamical systems subject to vibrations, revealed the existence of standing periodic waves and solitons in this system. However, this approach does not provide regular means for dealing with evolutionary problems: neither stability problems nor ones associated with propagating waves. In this work, we rigorously derive the evolution equations for long waves in the system, which turn out to be identical to the plus (or good) Boussinesq equation. With these equations one can find all the time-independent-profile solitary waves (standing solitons are a specific case of these propagating waves), which exist below the linear instability threshold; the standing and slow solitons are always unstable while fast solitons are stable. Depending on initial perturbations, unstable solitons either grow in an explosive manner, which means layer rupture in a finite time, or falls apart into stable solitons. The results are derived within the long-wave approximation as the linear stability analysis for the flat-interface state [D.V. Lyubimov and A.A. Cherepanov, Fluid Dynamics 21, 849 (1986)] reveals the instabilities of thin layers to be long wavelength.

  2. [Fear of falling].

    Science.gov (United States)

    Alcalde Tirado, Pablo

    2010-01-01

    Fear of falling (FF) can be considered as a protective response to a real threat, preventing the elderly from performing activities with high risk of falling, but can also lead to a restriction of the activities that will result in a long-term adverse effect on social, physical or cognitive functions. There is a prevalence of FF in 30% in the elderly who have no history of falls, and double that in those with a history of falling. Its prevalence is increased in women and with advanced age. Several scales have been developed to measure the psychological effects of FF, among which are noted are, the Fall Efficacy Scale (FES), the Activities-specific Balance and Confidence Scale (ABC), and the survey of activities and fear of falling in the elderly (SAFE). It has negative consequences in the functionality, the subjective feeling of well-being, and in the consequent loss of independence. The functional and physical deterioration, or the quality of life is clearly related to the FF, although it has not been established if these factors are cause or effect. Multiple interventions have been recommended, bringing about changes that reinforce their confidence to carry out activities. Interventions and research should promote a realistic and appropriate approach to the risk of falls and teach the elderly to perform activities safely. The reduction in FF is an important goal in itself to improve the subjective feeling of well-being, and the benefits could be increased if this reduction was also accompanied by an increase in safe behaviour, social participation, and activities of the daily life.

  3. ATLAS-TPX: a two-layer pixel detector setup for neutron detection and radiation field characterization

    Science.gov (United States)

    Bergmann, B.; Caicedo, I.; Leroy, C.; Pospisil, S.; Vykydal, Z.

    2016-10-01

    A two-layer pixel detector setup (ATLAS-TPX), designed for thermal and fast neutron detection and radiation field characterization is presented. It consists of two segmented silicon detectors (256 × 256 pixels, pixel pitch 55 μm, thicknesses 300 μm and 500 μm) facing each other. To enhance the neutron detection efficiency a set of converter layers is inserted in between these detectors. The pixelation and the two-layer design allow a discrimination of neutrons against γs by pattern recognition and against charged particles by using the coincidence and anticoincidence information. The neutron conversion and detection efficiencies are measured in a thermal neutron field and fast neutron fields with energies up to 600 MeV. A Geant4 simulation model is presented, which is validated against the measured detector responses. The reliability of the coincidence and anticoincidence technique is demonstrated and possible applications of the detector setup are briefly outlined.

  4. Preparation of Two-Layer Anion-Exchange Poly(ethersulfone Based Membrane: Effect of Surface Modification

    Directory of Open Access Journals (Sweden)

    Lucie Zarybnicka

    2016-01-01

    Full Text Available The present work deals with the surface modification of a commercial microfiltration poly(ethersulfone membrane by graft polymerization technique. Poly(styrene-co-divinylbenzene-co-4-vinylbenzylchloride surface layer was covalently attached onto the poly(ethersulfone support layer to improve the membrane electrochemical properties. Followed by amination, a two-layer anion-exchange membrane was prepared. The effect of surface layer treatment using the extraction in various solvents on membrane morphological and electrochemical characteristics was studied. The membranes were tested from the point of view of water content, ion-exchange capacity, specific resistance, permselectivity, FT-IR spectroscopy, and SEM analysis. It was found that the two-layer anion-exchange membranes after the extraction using tetrahydrofuran or toluene exhibited smooth and porous surface layer, which resulted in improved ion-exchange capacity, electrical resistance, and permselectivity of the membranes.

  5. Tensile Properties with or without Heat Dispersion of Automotive Needlepunched Carpets Made up of Two Layers of Different Materials

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yunqing; GUO Zhiying; DONG Xianghuai; LI Dequn

    2008-01-01

    Tensile properties of automotive needlepunched carpets made up of two layers of different materials (a fabric layer and a foam layer) in their thermoforming temperatures ranges with or without heat dispersion were discussed. Effects of forming temperature, extensile speed and fiber orientation on the tensile properties were studied based on an orthogonal experiment design. The experimental results show that automotive carpets are rate-dependent anisotropic materials and more strongly depend on forming temperature than the extensile speed and fiber orientation. Furthermore,contributions of the fabric layer and the foam layer to the overall tensile performance were investigated by comparing the tensile results of single fabric layer with those of the overall carpet. Both the fabric layer and the foam layer show positive effects on the overall tensile strength which is the combination of the two layers' tensile strength and independent of temperature, extensile speed and fiber orientation.On the other hand, their influences on the overall deformation are relatively complicated.

  6. Determining particle size distribution and refractive index in a two-layer tissue phantom by linearly polarized light

    Institute of Scientific and Technical Information of China (English)

    Yong Deng; Qiang Lu; Qingming Luo

    2006-01-01

    We report a new method for measuring particle size distribution (PSD) and refractive index of the top layer in a two-layer tissue phantom simulated epithelium tissue by varying the azimuth angle of incident linearly polarized light. The polarization gating technique is used to decouple the single and multiple scattering components in the returned signal. The theoretical model based on Mie theory is presented and a nonlinear inversion method - floating genetic algorithm - is applied to inverting the azimuth dependence of component of polarization light backscattered. The experiment results demonstrate that the size distribution and refractive index of the scatters of the top layer can be determined by measuring and analyzing the differential signal of the parallel and perpendicular components from a two-layer tissue phantom. The method implies to detect precancerous changes in human epithelial tissue.

  7. 降膜蒸发器旋液流态化在线自动清洗能力研究%Research on online fouling removal of spiral-flow fluidization in falling film evaporator

    Institute of Scientific and Technical Information of China (English)

    魏彪; 俞天兰; 彭德其; 张梅

    2011-01-01

    针对降膜蒸发器管内结垢问题,提出旋液流态化技术实现自动清洗。由结晶速率等效原理,将饱和溶液在加热面结晶问题等效为在冷却面结晶问题。以0.4m/s平均流速饱和硫酸钠溶液为例进行试验研究。结果表明:近壁面溶液在忽略管壁及污垢热阻的绝对过饱和度Δcsur为4.20%时,与空管连续运行0.5h总传热系数下降80%相比,管内加钢丝螺旋的总传热系数保持不变。Δcsur=5.60%时,钢丝螺旋达到最大清洗速率,超过此值总传热系数下降。Δcsur=6.46%时,加入体积分数1%的粒子,总传热系数未降反升,同未结垢时相比提高6%。降膜蒸发器旋液流态化既能在线自动清洗又可起到对流强化传热效果。其结构简单,便于工业推广。%To solve the fouling problem of falling film evaporator,a new online fouling removal technology of spiral-flow fluidization is developed.According to the equivalence principle of crystallization rate,the crystallization of supersaturated solution on heating tubes in evaporators is equivalent to that on cooling tubes of heat exchanger in experiments.Saturated sodium sulfate solution flows through the cooling tubes at the average speed of 0.4 m/s.The results show that as the absolute supersaturation near the tube surface(Δcsur) is 4.20%,the total heat transfer coefficient is not reduced under the condition of tubes with steel spiral-insert after continuous operation of 0.5h while it decreases by 80% under the condition of hollow tubes.When Δcsur is more than 5.60%,the total heat transfer coefficient will decrease.However,the total heat transfer coefficient does increase by 6% not decrease under the conditions of spiral-insert and fluidization of 1% volume fraction of particles,when Δcsur is 6.46%.The technology of spiral-flow fluidization can not only remove fouling online and automaticly,but also enhance the convection heat transfer in tube side.With its simple structure,it can

  8. Two-layer critical dimensions and overlay process window characterization and improvement in full-chip computational lithography

    Science.gov (United States)

    Sturtevant, John L.; Liubich, Vlad; Gupta, Rachit

    2016-04-01

    Edge placement error (EPE) was a term initially introduced to describe the difference between predicted pattern contour edge and the design target for a single design layer. Strictly speaking, this quantity is not directly measurable in the fab. What is of vital importance is the relative edge placement errors between different design layers, and in the era of multipatterning, the different constituent mask sublayers for a single design layer. The critical dimensions (CD) and overlay between two layers can be measured in the fab, and there has always been a strong emphasis on control of overlay between design layers. The progress in this realm has been remarkable, accelerated in part at least by the proliferation of multipatterning, which reduces the available overlay budget by introducing a coupling of overlay and CD errors for the target layer. Computational lithography makes possible the full-chip assessment of two-layer edge to edge distances and two-layer contact overlap area. We will investigate examples of via-metal model-based analysis of CD and overlay errors. We will investigate both single patterning and double patterning. For single patterning, we show the advantage of contour-to-contour simulation over contour to target simulation, and how the addition of aberrations in the optical models can provide a more realistic CD-overlay process window (PW) for edge placement errors. For double patterning, the interaction of 4-layer CD and overlay errors is very complex, but we illustrate that not only can full-chip verification identify potential two-layer hotspots, the optical proximity correction engine can act to mitigate such hotspots and enlarge the joint CD-overlay PW.

  9. Dynamics of the outflow and its effect on the hydraulics of two-layer exchange flows in a channel

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    This paper reports that an experimental study is conducted to examine the dynamics of the outflow in two-layer exchange flows in a channel connecting between two water bodies with a small density difference. The experiments reveal the generation of Kelvin-Helmholtz (KH) instabilities within the hydraulically sub-critical flow region of the channel. During maximal exchange, those KH instabilities develops into large-amplitude KH waves as they escape the channel exit into the reservoir. The propagation speed ...

  10. Two-Layer Microstructures Fabricated by One-Step Anisotropic Wet Etching of Si in KOH Solution

    Directory of Open Access Journals (Sweden)

    Han Lu

    2016-01-01

    Full Text Available Anisotropic etching of silicon in potassium hydroxide (KOH is an important technology in micromachining. The residue deposition from KOH etching of Si is typically regarded as a disadvantage of this technology. In this report, we make use of this residue as a second masking layer to fabricate two-layer complex structures. Square patterns with size in the range of 15–150 μm and gap distance of 5 μm have been designed and tested. The residue masking layer appears when the substrate is over-etched in hydrofluoric acid (HF solution over a threshold. The two-layer structures of micropyramids surrounded by wall-like structures are obtained according to the two different masking layers of SiO2 and residue. The residue masking layer is stable and can survive over KOH etching for long time to achieve deep Si etching. The process parameters of etchant concentration, temperature, etching time and pattern size have been investigated. With well-controlled two-layer structures, useful structures could be designed for applications in plasmonic and microfluidic devices in the future.

  11. Laboratory Research of the Two-Layer Liquid Dynamics at the Wind Surge in a Strait Canal

    Directory of Open Access Journals (Sweden)

    S.F. Dotsenko

    2017-06-01

    Full Text Available The results of laboratory experiments in a straight aerohydrocanal of the rectangular cross-section filled with the two-layer (fresh-salty liquid are represented. The disturbance generator is the air flow directed to the area above the canal. The cases of the two-layer liquid dynamics in the canal with the horizontal flat bottom and in the presence of the bottom obstacle of finite width are considered. It is shown that during the surge in the straight canal, one of the possible exchange mechanisms on the boundary of fresh and salty layers may consist in the salt water emissions (resulted from the Kelvin-Helmholtz instability to the upper freshwater layer. The subsequent eviction can possibly be accompanied by occurrence of undulations at the interface. Besides, the evictions can be followed by formation of the oscillating layer, i.e. the layer with maximum density gradient the oscillations of which propagate to the overlying layers. Presence of the bottom obstacle complicates the structure of the two-layer liquid motions. In particular, it results in emergence of the mixed layers and transformation of the flow behind the obstacle into a turbulent one, formation of the wave-like disturbances over the obstacle, sharp change of the interface position and occurrence of large-scale vortices with the horizontal axes. It is revealed that the maximum peak of the flow velocity horizontal component is shifted upstream from the obstacle.

  12. Distributed Processing System for Restoration of Electric Power Distribution Network Using Two-Layered Contract Net Protocol

    Science.gov (United States)

    Kodama, Yu; Hamagami, Tomoki

    Distributed processing system for restoration of electric power distribution network using two-layered CNP is proposed. The goal of this study is to develop the restoration system which adjusts to the future power network with distributed generators. The state of the art of this study is that the two-layered CNP is applied for the distributed computing environment in practical use. The two-layered CNP has two classes of agents, named field agent and operating agent in the network. In order to avoid conflicts of tasks, operating agent controls privilege for managers to send the task announcement messages in CNP. This technique realizes the coordination between agents which work asynchronously in parallel with others. Moreover, this study implements the distributed processing system using a de-fact standard multi-agent framework, JADE(Java Agent DEvelopment framework). This study conducts the simulation experiments of power distribution network restoration and compares the proposed system with the previous system. We confirmed the results show effectiveness of the proposed system.

  13. The News, Fall 2002.

    Science.gov (United States)

    Giles, Ray, Ed.

    2002-01-01

    This fall 2002 newsletter from the Community College League of California contains several articles, news stories, and the brochure from the 2002 Annual Convention, "Celebrating the Way California LEARNS." Articles include: (1) "Nursing Shortage Poses Dilemma for Colleges: Access vs. Efficiency," a discussion of the debate over…

  14. FHR Iowa Falls Approval

    Science.gov (United States)

    This October 22, 2015, letter from EPA approves the petition from Flint Hills Resources, LLC, regarding non-grandfathered ethanol produced through the FHR Iowa Falls Process, qualifying under the Clean Air Act for renewable fuel (D-code 6) RINs under the R

  15. Novel Hierarchical Fall Detection Algorithm Using a Multiphase Fall Model

    Science.gov (United States)

    Hsieh, Chia-Yeh; Liu, Kai-Chun; Huang, Chih-Ning; Chu, Woei-Chyn; Chan, Chia-Tai

    2017-01-01

    Falls are the primary cause of accidents for the elderly in the living environment. Reducing hazards in the living environment and performing exercises for training balance and muscles are the common strategies for fall prevention. However, falls cannot be avoided completely; fall detection provides an alarm that can decrease injuries or death caused by the lack of rescue. The automatic fall detection system has opportunities to provide real-time emergency alarms for improving the safety and quality of home healthcare services. Two common technical challenges are also tackled in order to provide a reliable fall detection algorithm, including variability and ambiguity. We propose a novel hierarchical fall detection algorithm involving threshold-based and knowledge-based approaches to detect a fall event. The threshold-based approach efficiently supports the detection and identification of fall events from continuous sensor data. A multiphase fall model is utilized, including free fall, impact, and rest phases for the knowledge-based approach, which identifies fall events and has the potential to deal with the aforementioned technical challenges of a fall detection system. Seven kinds of falls and seven types of daily activities arranged in an experiment are used to explore the performance of the proposed fall detection algorithm. The overall performances of the sensitivity, specificity, precision, and accuracy using a knowledge-based algorithm are 99.79%, 98.74%, 99.05% and 99.33%, respectively. The results show that the proposed novel hierarchical fall detection algorithm can cope with the variability and ambiguity of the technical challenges and fulfill the reliability, adaptability, and flexibility requirements of an automatic fall detection system with respect to the individual differences. PMID:28208694

  16. Optical characterization of two-layered turbid media for non-invasive, absolute oximetry in cerebral and extracerebral tissue.

    Directory of Open Access Journals (Sweden)

    Bertan Hallacoglu

    Full Text Available We introduce a multi-distance, frequency-domain, near-infrared spectroscopy (NIRS method to measure the optical coefficients of two-layered media and the thickness of the top layer from diffuse reflectance measurements. This method features a direct solution based on diffusion theory and an inversion procedure based on the Levenberg-Marquardt algorithm. We have validated our method through Monte Carlo simulations, experiments on tissue-like phantoms, and measurements on the forehead of three human subjects. The Monte Carlo simulations and phantom measurements have shown that, in ideal two-layered samples, our method accurately recovers the top layer thickness (L, the absorption coefficient (µ a and the reduced scattering coefficient (µ' s of both layers with deviations that are typically less than 10% for all parameters. Our method is aimed at absolute measurements of hemoglobin concentration and saturation in cerebral and extracerebral tissue of adult human subjects, where the top layer (layer 1 represents extracerebral tissue (scalp, skull, dura mater, subarachnoid space, etc. and the bottom layer (layer 2 represents cerebral tissue. Human subject measurements have shown a significantly greater total hemoglobin concentration in cerebral tissue (82±14 µM with respect to extracerebral tissue (30±7 µM. By contrast, there was no significant difference between the hemoglobin saturation measured in cerebral tissue (56%±10% and extracerebral tissue (62%±6%. To our knowledge, this is the first time that an inversion procedure in the frequency domain with six unknown parameters with no other prior knowledge is used for the retrieval of the optical coefficients and top layer thickness with high accuracy on two-layered media. Our absolute measurements of cerebral hemoglobin concentration and saturation are based on the discrimination of extracerebral and cerebral tissue layers, and they can enhance the impact of NIRS for cerebral hemodynamics and

  17. Radiative transfer theory for passive microwave remote sensing of a two-layer random medium with cylindrical structures

    Science.gov (United States)

    Chuang, S. L.; Kong, J. A.; Tsang, L.

    1980-01-01

    A model of the vegetation layer as a two-layer random medium with a small correlation length l sub rho in the horizontal direction, and a large correlation length l sub z in the vertical direction, is presented for fields with cylindrical structures. As l sub z approaches infinity, closed form solutions are derived for the brightness temperatures; the kernels in the scattering terms of the radiative transfer equations result in delta functions showing that forward scattering is dominant over all other directions. The results are compared with the Gaussian quadrature method data for numerical solution of the radiative transfer equations.

  18. WAVES GENERATED BY A 3D MOVING BODY IN A TWO-LAYER FLUID OF FINITE DEPTH

    Institute of Scientific and Technical Information of China (English)

    ZHU Wei; YOU Yun-xiang; MIAO Guo-ping; ZHAO Feng; ZHANG Jun

    2005-01-01

    This paper is concerned with the waves generated by a 3-D body advancing beneath the free surface with constant speed in a two-layer fluid of finite depth. By applying Green's theorem, a layered integral equation system based on the Rankine source for the perturbed velocity potential generated by the moving body was derived with the potential flow theory. A four-node isoparametric element method was used to treat with the solution of the layered integral equation system. The surface and interface waves generated by a moving ball were calculated numerically. The results were compared with the analytical results for a moving source with constant velocity.

  19. The Resource. Fall 2001

    Science.gov (United States)

    2001-01-01

    Adams, Director of Scientific Visualization, initiated a Bring Your Own Data ( BYOD ) workshop for MSRC users. The first workshop was held June 25-26 in...leverage these assets in their future work. The first BYOD workshop was definitely a benefit to the users. Chris Stone, in particular was able to...publications 28 ERDC MSRC The Resource, Fall 2001 ac ro ny m s AG Access Grid AMR Adaptive Mesh Refinement BYOD Bring Your Own Data CDC Control Data

  20. Quasi-two-layer finite-volume scheme for modeling shallow water flows with the presence of external forces

    CERN Document Server

    Karelsky, K V; Slavin, A G

    2011-01-01

    The numerical method for study of hydrodynamic flows over an arbitrary bed profile in the presence of external force is proposed in this paper. This method takes into account the external force effect, it uses the quasi-two-layer model of hydrodynamic flows over a stepwise boundary with consideration of features of the flow near the step. A distinctive feature of the proposed method is the consideration of the properties of the process of the waterfall, namely the fluid flow on the step in which the fluid does not wet part of the vertical wall of the step. The presence of dry zones in the vertical part of the step indicates violation of the conditions of hydrostatic flow. The quasi-two-layer approach allows to determine the size of the dry zone of the vertical component of the step. Consequently it gives an opportunity to figure out the amount of kinetic energy dissipation. There are performed the numerical simulations based on the proposed algorithm of various physical phenomena, such as a breakdown of the r...

  1. Linear and nonlinear properties of reduced two-layer models for non-hydrostatic free-surface flow

    Science.gov (United States)

    Bai, Yefei; Cheung, Kwok Fai

    2016-11-01

    A two-layer model with uniform non-hydrostatic pressure in the bottom produces favorable dispersion properties for coastal wave transformation at the computational requirements of a one-layer model. We derive the nonlinear governing equations and the corresponding dispersion relation, shoaling gradient, and super- and sub-harmonics to understand the theoretical performance of this reduced model. With the layer interface near the bottom, the dispersion relation shows an extended applicable range into deeper water at the expense of a slight overestimation of the celerity in intermediate water depth. The shoaling gradient rapidly converges to the exact solution in the shallow and intermediate depth range. These complementary characteristics allow identification of an optimal interface position for both linear wave properties. The resulting model exhibits good nonlinear performance in shallow and intermediate water depth and produces super- and sub-harmonics comparable to a two-layer model. Numerical tests involving standing waves show the reduced model has smaller discretization errors in the dispersion relation comparing to a one-layer model. Case studies of regular wave transformation over a submerged bar and a uniform slope provide comparison with laboratory data and demonstrate the linear and nonlinear properties derived from the governing equations. The good shoaling and nonlinear properties give rise to accurate waveforms in both cases, while dispersion errors from the governing equations and numerical schemes accumulate over time leading to phase shifts of the modeled waves.

  2. Acoustic scattering by a two-layer cylindrical tube immersed in a fluid medium: Existence of a pseudo wave.

    Science.gov (United States)

    Elhanaoui, Abdelkader; Aassif, Elhoucein; Maze, Gérard; Décultot, Dominique

    2016-02-01

    The present paper studies the acoustic signal backscattered by an air-filled copper–solid polymer two-layer cylindrical tube immersed in water. The work is done from the calculation of the backscattered pressure, an inverse Fourier Transform, which allows us to obtain an impulse signal. Smoothed pseudo Wigner–Ville and Concentrated spectrogram representations have been chosen to analyze the scattering phenomenon. For reduced frequencies ranging from 0.1 to 200, the resonance trajectories and time–frequency images have shown the presence of the guided waves. The bifurcation of the A0 wave into the A0(-) and the A0(+) waves has also been observed. The authors provide the phase and the group velocities of guided waves and investigate the differences between curves. The findings are then compared with those obtained for the copper and the solid polymer one-layer cylindrical tubes. Group velocity values have also been extracted from smoothed pseudo Wigner–Ville and Concentrated spectrogram time–frequency images. A good agreement with the theory has, therefore, been observed. The study of acoustic backscattering by a copper–solid polymer two-layer tube has revealed the interaction and the coupling of guided waves, specially the presence of a pseudo A1 wave; which is a very interesting, remarkable phenomenon.

  3. Modeling of PZT-induced Lamb wave propagation in structures by using a novel two-layer spectral finite element

    Science.gov (United States)

    Liu, Xiaotong; Zhou, Li; Ouyang, Qinghua

    2016-04-01

    This paper presents a novel two-layer spectral finite element model, consisting of PZT wafer and host structure, to simulate PZT-induced Lamb wave propagation in beam-like and plate-like structures. Based on the idea of equal displacement on the interface between PZT wafer and host structure, the one-dimensional spectral beam element of PZT-host beam and two-dimensional spectral plate element of PZT-host plate are considered as one hybrid element, respectively. A novel approach is proposed by taking the coupling effect of piezoelectric transducers in the thickness direction into account. The dynamic equation of the two-layer spectral element is derived from Hamilton's principle. Validity of the developed spectral finite element is verified through numerical simulation. The result indicates that, compared with the conventional finite element method (FEM) based on elasticity, the proposed spectral finite element is proved to have a high accuracy in modeling Lamb wave propagation, meanwhile, significantly improve the calculation efficiency.

  4. A Numerical Study on Water Waves Generated by A Submerged Moving Body in A Two-Layer Fluid System

    Institute of Scientific and Technical Information of China (English)

    YANG Jia-Zhen; NG Chiu-On; ZHANG Dao-Hua

    2009-01-01

    This is a numerical study on the time development of surface waves generated by a submerged body moving steadily in a two-layer fluid system, in which a layer of water is underlain by a layer of viscous mud. The fully nonlinear Navier-Stokes equations are solved on FLUENT with the Volume-of-Fluid (VOF) multiphase scheme in order to simulate the free surface waves as well as the water-mud interface waves as functions of time. The numerical model is validated by mimick-ing a reported experiment in a one-layer system before it is applied to a two-layer system, it is found that the presence of bottom mud in a water layer can lead to large viscous damping of the surface waves. For the investigation of the problem systematically, the effects of the Froude number and the mud layer thickness, density and viscosity relative to those of water are evaluated and discussed in detail.

  5. Equivalent circuit models of two-layer flexure beams with excitation by temperature, humidity, pressure, piezoelectric or piezomagnetic interactions

    Directory of Open Access Journals (Sweden)

    U. Marschner

    2014-09-01

    Full Text Available Two-layer flexure beams often serve as basic transducers in actuators and sensors. In this paper a generalized description of their stimuli-influenced mechanical behavior is derived. For small deflection angles this description includes a multi-port circuit or network representation with lumped elements for a beam part of finite length. A number of coupled finite beam parts model the dynamic behavior including the first natural frequencies of the beam. For piezoelectric and piezomagnetic interactions, reversible transducer models are developed. The piezomagnetic two-layer beam model is extended to include solenoid and planar coils. Linear network theory is applied in order to determine network parameters and to simplify the circuit representation. The resulting circuit model is the basis for a fast simulation of the dynamic system behavior with advanced circuit simulators and, thus, the optimization of the system. It is also a useful tool for understanding and explaining this multi-domain system through basic principles of general system theory.

  6. Interaction of water waves with small undulations on a porous bed in a two-layer ice-covered fluid

    Science.gov (United States)

    Panda, Srikumar; Martha, S. C.

    2013-12-01

    The scattering problem involving water waves by small undulation on the porous ocean-bed in a two-layer fluid, is investigated within the framework of the two-dimensional linear water wave theory where the upper layer is covered by a thin uniform sheet of ice modeled as a thin elastic plate. In such a two-layer fluid there exist waves with two different modes, one with a lower wave number propagate along the ice-cover whilst those with a higher wave number propagate along the interface. An incident wave of a particular wave number gets reflected and transmitted over the bottom undulation into waves of both modes. Perturbation analysis in conjunction with the Fourier transform technique is used to derive the first-order corrections of reflection and transmission coefficients for both the modes due to incident waves of two different modes. One special type of bottom topography is considered as an example to evaluate the related coefficients in detail. These coefficients are depicted in graphical forms to demonstrate the transformation of wave energy between the two modes and also to illustrate the effects of the ice sheet and the porosity of the undulating bed.

  7. A constructive algorithm to solve "convex recursive deletion" (CoRD) classification problems via two-layer perceptron networks.

    Science.gov (United States)

    Cabrelli, C; Molter, U; Shonkwiler, R

    2000-01-01

    A sufficient condition that a region be classifiable by a two-layer feedforward neural net (a two-layer perceptron) using threshold activation functions is that either it be a convex polytope or that intersected with the complement of a convex polytope in its interior, or that intersected with the complement of a convex polytope in its interior or ... recursively. These have been called convex recursive deletion (CoRD) regions.We give a simple algorithm for finding the weights and thresholds in both layers for a feedforward net that implements such a region. The results of this work help in understanding the relationship between the decision region of a perceptron and its corresponding geometry in input space. Our construction extends in a simple way to the case that the decision region is the disjoint union of CoRD regions (requiring three layers). Therefore this work also helps in understanding how many neurons are needed in the second layer of a general three-layer network. In the event that the decision region of a network is known and is the union of CoRD regions, our results enable the calculation of the weights and thresholds of the implementing network directly and rapidly without the need for thousands of backpropagation iterations.

  8. Transient flexural-and capillary-gravity waves due to disturbances in two-layer density-stratified fluid

    Institute of Scientific and Technical Information of China (English)

    LU Dong-qiang; SUN Cui-zhi

    2013-01-01

    Generation of the transient flexural-and capillary-gravity waves by impulsive disturbances in a two-layer fluid is investigated analytically.The upper fluid is covered by a thin elastic plate or by an inertial surface with the capillary effect.The density of each of the two immiscible layers is constant.The fluids are assumed to be inviscid and incompressible and the motion be irrotational.A point force on the surface and simple mass sources in the upper and lower fluid layers are considered.A linear system is established within the framework of potential theory.The integral solutions for the surface and interfacial waves are obtained by means of the Laplace-Fourier transform.A new representation for the dispersion relation of flexural-and capillary-gravity waves in a two-layer fluid is derived.The asymptotic representations of the wave motions are derived for large time with a fixed distance-to-time ratio with the Stokes and Scorer methods of stationary phase.It is shown that there are two different modes,namely the surface and interfacial wave modes.The wave systems observed depend on the relation between the observer's moving speed and the intrinsic minimal and maximal group velocities.

  9. Fall prevention walker during rehabilitation

    Science.gov (United States)

    Tee, Kian Sek; E, Chun Zhi; Saim, Hashim; Zakaria, Wan Nurshazwani Wan; Khialdin, Safinaz Binti Mohd; Isa, Hazlita; Awad, M. I.; Soon, Chin Fhong

    2017-09-01

    This paper proposes on the design of a walker for the prevention of falling among elderlies or patients during rehabilitation whenever they use a walker to assist them. Fall happens due to impaired balance or gait problem. The assistive device is designed by applying stability concept and an accelerometric fall detection system is included. The accelerometric fall detection system acts as an alerting device that acquires body accelerometric data and detect fall. Recorded accelerometric data could be useful for further assessment. Structural strength of the walker was verified via iterations of simulation using finite element analysis, before being fabricated. Experiments were conducted to identify the fall patterns using accelerometric data. The design process and detection of fall pattern demonstrates the design of a walker that could support the user without fail and alerts the helper, thus salvaging the users from injuries due to fall and unattended situation.

  10. Exercises to help prevent falls

    Science.gov (United States)

    ... ency/patientinstructions/000493.htm Exercises to help prevent falls To use the sharing features on this page, ... even more serious injuries. Exercising can help prevent falls because it can: Make your muscles stronger and ...

  11. Falls in degenerative cerebellar ataxias

    NARCIS (Netherlands)

    van de Warrenburg, Bart P C; Steijns, Janneke A G; Munneke, Marten; Kremer, Berry P H; Bloem, Bastiaan R

    2005-01-01

    We retrospectively and prospectively assessed the frequency and characteristics of falls in patients with degenerative cerebellar ataxias. The results show that falls occur very frequently in patients with degenerative cerebellar ataxias and that these falls are serious and often lead to injuries or

  12. The falls and the fear of falling among elderly institutionalized

    Directory of Open Access Journals (Sweden)

    Patrícia Almeida

    2013-06-01

    Full Text Available In the present study it is intended to characterize the history of falls and to evaluate the fear to fall in aged institutionalized. The sample is composed for 113 institutionalized aged people, 32 men and 81 women with a average 82,96 ± 7,03 age of years. The data had been collected by means of a questionnaire and statistical analyzed (descriptive statistics, parametric tests - Test T and Anova - Test U-Mann Whitney, and Test of Kruskal-Wallis – and the Test of Tukey. The results point in the direction of that the women present a bigger number of falls (24.8% and greater fear to fall (Med=55. The falls had occurred in its majority in the context of the room of the institutions. It was verified that people who had at least a fall experience present greater fear to fall comparatively (Med=55 with that they had not the same had no incident of fall in period of time (Med=77. Our results come to strengthen the hypothesis of the changeable sex to be able to be considered a factor of fall risk. Aged that they present a history of falls seems to be more vulnerable to develop the fear to fall.

  13. [Fall risk and fracture. Aging and fall/fracture].

    Science.gov (United States)

    Kozaki, Koichi

    2013-05-01

    Fall deteriorates QOL and ADL of elderly people, especially when they suffer from hip and vertebral fractures. It is not easy to identify the cause of falling, because falling usually result from multiple factors. Among various potential causes, osteoporosis, osteoarthritis, medication of hypnotic drugs, and environmental factors are important, because they are frequent and can be modifiable. When evaluating fall risks, grasping power, one-leg standing time, timed up&go test, are useful. On the other hand, fall risk index, 22-item self-assessment test, is easy and even better in predicting future falls. In the Cochrane systematic review article 2009, exercise such as Tai-Chi, withdrawal of hypnotic drugs, and vitamin D supplementation are shown to prevent falls in community-dwelling elderly.

  14. Why Rhodes must fall

    OpenAIRE

    Newsinger, J

    2016-01-01

    The international Rhodes Must Fall campaign has reinvigorated public interest in the legacy of Cecil Rhodes, Empire and the production of historical memory. But it has also been subject to a fierce backlash in the rightwing media, which has fought against the campaign at an Oxford college to remove a statue of Cecil Rhodes both on the grounds of free speech (and the right to offend) and on the grounds that Rhodes must be judged by the standards of his time. Here, the author revisits Rhodes’ l...

  15. `In free fall'

    Science.gov (United States)

    Beijerinck, Herman C. W.

    2014-01-01

    Physicists in the lead of a fiction book or a play, that's a rare event! Writers in general do not understand physics, while physicists seldom have the talent of writing for a large audience. So when it happens, we should rejoice. The up-and-coming German author Juli Zeh [1] (1974), who studied law, has succeeded in combining beautiful prose, psychological drama, crime and physics in a challenging book `In free fall' [2]. A good friend of hers, Bettina Bruinier, has put the core message of the book into a compelling play in the `Volkstheater' in Munich [1]. Yes, it can be done.

  16. Coins falling in water

    CERN Document Server

    Heisinger, Luke; Kanso, Eva

    2013-01-01

    When a coin falls in water, its trajectory is one of four types determined by its dimensionless moment of inertia $I^\\ast$ and Reynolds number Re: (A) steady; (B) fluttering; (C) chaotic; or (D) tumbling. The dynamics induced by the interaction of the water with the surface of the coin, however, makes the exact landing site difficult to predict a priori. Here, we describe a carefully designed experiment in which a coin is dropped repeatedly in water, so that we can determine the probability density functions (pdf) associated with the landing positions for each of the four trajectory types, all of which are radially symmetric about the center-drop line. In the case of the steady mode, the pdf is approximately Gaussian distributed, with variances that are small, indicating that the coin is most likely to land at the center, right below the point it is dropped from. For the other falling modes, the center is one of the least likely landing sites. Indeed, the pdf's of the fluttering, chaotic and tumbling modes ar...

  17. Two-layer anti-reflection coating with mullite and polyimide foam for large-diameter cryogenic infrared filters.

    Science.gov (United States)

    Inoue, Yuki; Hamada, Takaho; Hasegawa, Masaya; Hazumi, Masashi; Hori, Yasuto; Suzuki, Aritoki; Tomaru, Takayuki; Matsumura, Tomotake; Sakata, Toshifumi; Minamoto, Tomoyuki; Hirai, Tohru

    2016-12-01

    We have developed a novel two-layer anti-reflection (AR) coating method for large-diameter infrared (IR) filters made of alumina, for use at cryogenic temperatures in millimeter wave measurements. Thermally sprayed mullite and polyimide foam (Skybond Foam) are used as the AR material. An advantage of the Skybond Foam is that the index of refraction is chosen between 1.1 and 1.7 by changing the filling factor. Combination with mullite is suitable for wide-band millimeter wave measurements with sufficient IR cutoff capability. We present the material properties, fabrication of a large-diameter IR filter made of alumina with this AR coating method, and characterizations at cryogenic temperatures. This technology can be applied to a low-temperature receiver system with a large-diameter focal plane for next-generation cosmic microwave background polarization measurements, such as POLARBEAR-2 (PB-2).

  18. Identification of a Segment of the Yield Surface of a Two-Layer Pa38/M2R Composite

    Science.gov (United States)

    Uscinowicz, R. R.

    2016-05-01

    The aim of this study was to identify the initial yield surface of a two-layer aluminum alloy-copper composite in the range of small elastic-plastic deformations. Experimental tests in a plane stress state were conducted by loading tubular composite specimens with various combinations of axial forces and torque. The metal layers were joined together by using an epoxy resin. Independent studies were carried out for component of the composite under identical conditions. The yield surfaces obtained were compared with those given by the Huber-von Mises-Hencky and Tresca-Guest yield criteria. The yield criterion for the tested composite found by using a modified form of the rule of mixtures is presented. The yield surfaces of a Pa38/M2R composite and its components demonstrated the isotropic hardening.

  19. Two-layer radio frequency MEMS fractal capacitors in PolyMUMPS for S-band applications

    KAUST Repository

    Elshurafa, Amro M.

    2012-07-23

    In this Letter, the authors fabricate for the first time MEMS fractal capacitors possessing two layers and compare their performance characteristics with the conventional parallel-plate capacitor and previously reported state-of-the-art single-layer MEMS fractal capacitors. Explicitly, a capacitor with a woven structure and another with an interleaved configuration were fabricated in the standard PolyMUMPS surface micromachining process and tested at S-band frequencies. The self-resonant frequencies of the fabricated capacitors were close to 10GHz, which is better than that of the parallel-plate capacitor, which measured only 5.5GHz. Further, the presented capacitors provided a higher capacitance when compared with the state-of-the-art-reported MEMS fractal capacitors created using a single layer at the expense of a lower quality factor. © 2012 The Institution of Engineering and Technology.

  20. Two-layer anti-reflection coating with mullite and polyimide foam for large-diameter cryogenic infrared filters

    CERN Document Server

    Inoue, Yuki; Hasegawa, Masaya; Hazumi, Masashi; Hori, Yasuto; Suzuki, Aritoki; Tomaru, Takayuki; Matsumura, Tomotake; Sakata, Toshifumi; Minamoto, Tomoyuki; Hirai, Tohru

    2016-01-01

    We have developed a novel two-layer anti-reflection (AR) coating method for large-diameter infrared (IR) filters made of alumina, for the use at cryogenic temperatures in millimeter wave measurements. Thermally- sprayed mullite and polyimide foam (Skybond Foam) are used as the AR material. An advantage of the Skybond Foam is that the index of refraction is chosen between 1.1 and 1.7 by changing the filling factor. Combination with mullite is suitable for wide-band millimeter wave measurements with sufficient IR cutoff capability. We present the material properties, fabrication of a large-diameter IR filter made of alumina with this AR coating method, and characterizations at cryogenic temperatures. This technology can be applied to a low-temperature receiver system with a large-diameter focal plane for next-generation cosmic microwave background (CMB) polarization measurements, such as POLARBEAR-2 (PB-2).

  1. Efficient and stable proton acceleration by irradiating a two-layer target with a linearly polarized laser pulse

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H. Y.; Yan, X. Q.; Chen, J. E.; He, X. T. [State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China) and Key Lab of High Energy Density Physics Simulation, CAPT, Peking University, Beijing 100871 (China); Ma, W. J.; Bin, J. H.; Schreiber, J.; Tajima, T.; Habs, D. [Fakultaet fuer Physik, Ludwig-Maximilians-Universitaet Muenchen, Am Coulombwall 1, 85748 Garching (Germany) and Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Str. 1, 85748 Garching (Germany)

    2013-01-15

    We report an efficient and stable scheme to generate {approx}200 MeV proton bunch by irradiating a two-layer targets (near-critical density layer+solid density layer with heavy ions and protons) with a linearly polarized Gaussian pulse at intensity of 6.0 Multiplication-Sign 10{sup 20} W/cm{sup 2}. Due to self-focusing of laser and directly accelerated electrons in the near-critical density layer, the proton energy is enhanced by a factor of 3 compared to single-layer solid targets. The energy spread of proton is also remarkably reduced. Such scheme is attractive for applications relevant to tumor therapy.

  2. Hierarchical modeling and control of hybrid systems with two layers; Hierarchische Modellierung und Regelung hybrider Systeme auf zwei Ebenen

    Energy Technology Data Exchange (ETDEWEB)

    Stursberg, Olaf; Paschedag, Tina; Rungger, Matthias; Ding, Hao [Kassel Univ. (Germany). Fachgebiet Regelungs- und Systemtheorie

    2010-08-15

    While hybrid dynamic models are, to a certain degree, established for modeling systems with heterogeneous dynamics, most approaches for design and analysis of hybrid systems are restricted to monolithic models without hierarchy. This contribution first shows, how modular hybrid systems with two layers of decision, as appropriate for representing manufacturing systems for example, can be modeled systematically. The second part proposes a technique for fixing discrete inputs (for coordinating control) and continuous inputs (for embedded continuous controllers) in combination. The method uses a graph-based search on the upper decision layer, while principles of predictive control are used on the lower layer. The procedure of modeling and control is illustrated for a manufacturing process. (orig.)

  3. Two-layer optical model of skin for early, non-invasive detection of wound development on the diabetic foot

    Science.gov (United States)

    Yudovsky, Dmitry; Nouvong, Aksone; Schomacker, Kevin; Pilon, Laurent

    2010-02-01

    Foot ulceration is a debilitating comorbidity of diabetes that may result in loss of mobility and amputation. Optical detection of cutaneous tissue changes due to inflammation and necrosis at the preulcer site could constitute a preventative strategy. A commercial hyperspectral oximetry system was used to measure tissue oxygenation on the feet of diabetic patients. A previously developed predictive index was used to differentiate preulcer tissue from surrounding healthy tissue with a sensitivity of 92% and specificity of 80%. To improve prediction accuracy, an optical skin model was developed treating skin as a two-layer medium and explicitly accounting for (i) melanin content and thickness of the epidermis, (ii) blood content and hemoglobin saturation of the dermis, and (iii) tissue scattering in both layers. Using this forward model, an iterative inverse method was used to determine the skin properties from hyperspectral images of preulcerative areas. The use of this information in lowering the false positive rate was discussed.

  4. Oblique wave scattering by an undulating porous bottom in a two-layer ice-covered fluid

    Science.gov (United States)

    Panda, Srikumar

    2016-06-01

    The present study analyzes the reflection and transmission phenomenon of water-waves in a two-layer ice-covered system. The upper layer is covered by an ice-sheet, whereas the bottom of the lower layer is undulated and permeable. By using regular perturbation analysis and Fourier transform technique, the problem is solved and the first order reflection and transmission coefficients are determined. It is found that these coefficients depend on the shape as well as the permeability of the undulating bottom. Therefore, from the practical viewpoint, an undulating bottom topography is considered to determine all the aforesaid coefficients. The role of various system parameters, such as porosity, angle of incidence and ice parameters, are discussed to analyze the transformation of incident water wave energy from one layer to another layer. The outcomes are demonstrated in graphical forms.

  5. Synthesis and absorbing mechanism of two-layer microwave absorbers containing polycrystalline iron fibers and carbonyl iron

    Science.gov (United States)

    Ding, Qingwei; Zhang, Mingang; Zhang, Cunrui; Qian, Tianwei

    2013-04-01

    Polycrystalline iron fibers were fabricated by α-FeOOH fiber precursors. Two-layer microwave absorber had been prepared by as-prepared polycrystalline iron fibers and carbonyl iron. The structure, morphology and properties of the composites were characterized with X-ray diffraction, scanning electron microscope and Network Analyzer. The complex permittivity and reflection loss (dB) of the composites were measured employing vector network analyzer model PNA 3629D vector in the frequency range between 30 and 6000 MHz. The thickness effect of the carbonyl iron layer on the microwave loss properties of the composites was investigated. A possible microwave-absorbing mechanism of polycrystalline iron fibers/carbonyl iron composite was proposed. The polycrystalline iron fibers/carbonyl iron composite can find applications in suppression of electromagnetic interference, and reduction of radar signature.

  6. Synchronization in a coupled two-layer quasigeostrophic model of baroclinic instability – Part 1: Master-slave configuration

    Directory of Open Access Journals (Sweden)

    P. L. Read

    2009-08-01

    Full Text Available Synchronization is studied using a pair of diffusively-coupled, two-layer quasi-geostrophic systems each comprising a single baroclinic wave and a zonal flow. In particular, the coupling between the systems is in the well-known master-slave or one-way configuration. Nonlinear time series analysis, phase dynamics, and bifurcation diagrams are used to study the dynamics of the coupled system. Phase synchronization, imperfect synchronization (phase slips, or complete synchronization are found, depending upon the strength of coupling, when the systems are either in a periodic or a chaotic regime. The results of investigations when the dynamics of each system are in different regimes are also presented. These results also show evidence of phase synchronization and signs of chaos control.

  7. Monte carlo diffusion hybrid model for photon migration in a two-layer turbid medium in the frequency domain.

    Science.gov (United States)

    Alexandrakis, G; Farrell, T J; Patterson, M S

    2000-05-01

    We propose a hybrid Monte Carlo (MC) diffusion model for calculating the spatially resolved reflectance amplitude and phase delay resulting from an intensity-modulated pencil beam vertically incident on a two-layer turbid medium. The model combines the accuracy of MC at radial distances near the incident beam with the computational efficiency afforded by a diffusion calculation at further distances. This results in a single forward calculation several hundred times faster than pure MC, depending primarily on model parameters. Model predictions are compared with MC data for two cases that span the extremes of physiologically relevant optical properties: skin overlying fat and skin overlying muscle, both in the presence of an exogenous absorber. It is shown that good agreement can be achieved for radial distances from 0.5 to 20 mm in both cases. However, in the skin-on-muscle case the choice of model parameters and the definition of the diffusion coefficient can lead to some interesting discrepancies.

  8. Falling Film Evaporator Throttle Orifice Calculation and its Adjustment to the Influence of Heating Temperature%降膜式蒸发器节流孔板的计算及其调整对加热温度的影响

    Institute of Scientific and Technical Information of China (English)

    刘殿宇

    2014-01-01

    决定降膜式蒸发器温度高低的参数主要有两个:一个是一效蒸汽的压力。一个是冷凝器的使用效果。但在正常使用情况下,各效温度可在一定范围内进行微调,这种调整即为通过调换各效壳程中上下不凝性气体出口的节流孔板的孔径来实现,从而达到某效蒸发温度的需要。上下不凝性气体接口主要是为真空泵抽取不凝性气体而设置。节流孔板孔径小加热温度高,反之则低。仅以CNJM03-3200型三效降膜式蒸发器在茶粉生产中的应用为例进行阐述。%There are two factors determining the temperature of falling film evaporator: one is pressure of one-effect stream;the other is using effect of condenser. Under the ordinary circumstance,temperature of every effect can be slightly adjusted via adjusting throttle orifice aperture of up-and-down un-condensed gas outlet hole in shell sides to lower the temperature. Up-and-down un-condensed gas outlet hole is designed for vacuum extraction of the gas. The heating temperature is high when throttle orifice aperture is small,or vice versa. This paper uses Mode CNJM03-3200 three-effect falling film evaporator applied in the production of tea powder as an example to discuss the topics.

  9. A two-layer depth-averaged approach to describe the regime stratification in collapses of dry granular columns

    Science.gov (United States)

    Sarno, L.; Carravetta, A.; Martino, R.; Tai, Y. C.

    2014-10-01

    The dynamics of dry granular flows is still insufficiently understood. Several depth-averaged approaches, where the flow motion is described through hydrodynamic-like models with suitable resistance laws, have been proposed in the last decades to describe the propagation of avalanches and debris flows. Yet, some important features of the granular flow dynamics cannot be well delivered. For example, it is very challenging to capture the progressive deposition process, observed in collapses and dam-break flows over rough beds, where an upper surface flow is found to coexist with a lower creeping flow. The experimental observations of such flows suggest the existence of a flow regime stratification caused by different momentum transfer mechanisms. In this work, we propose a two-layer depth-averaged model, aiming at describing such a stratification regime inside the flowing granular mass. The model equations are derived for both two-dimensional plane and axi-symmetric flows. Mass and momentum balances of each layer are considered separately, so that different constitutive laws are introduced. The proposed model is equipped with a closure equation accounting for the mass flux at the interface between the layers. Numerical results are compared with experimental data of axi-symmetric granular collapses to validate the proposed approach. The model delivers sound agreement with experimental data when the initial aspect ratios are small. In case of large initial aspect ratios, it yields a significant improvement in predicting the final shape of deposit and also the run-out distances. Further comparisons with different numerical models show that the two-layer approach is capable of correctly describing the main features of the final deposit also in the case of two-dimensional granular collapses.

  10. Mem-ADSVM: A two-layer multi-label predictor for identifying multi-functional types of membrane proteins.

    Science.gov (United States)

    Wan, Shibiao; Mak, Man-Wai; Kung, Sun-Yuan

    2016-06-07

    Identifying membrane proteins and their multi-functional types is an indispensable yet challenging topic in proteomics and bioinformatics. However, most of the existing membrane-protein predictors have the following problems: (1) they do not predict whether a given protein is a membrane protein or not; (2) they are limited to predicting membrane proteins with single-label functional types but ignore those with multi-functional types; and (3) there is still much room for improvement for their performance. To address these problems, this paper proposes a two-layer multi-label predictor, namely Mem-ADSVM, which can identify membrane proteins (Layer I) and their multi-functional types (Layer II). Specifically, given a query protein, its associated gene ontology (GO) information is retrieved by searching a compact GO-term database with its homologous accession number. Subsequently, the GO information is classified by a binary support vector machine (SVM) classifier to determine whether it is a membrane protein or not. If yes, it will be further classified by a multi-label multi-class SVM classifier equipped with an adaptive-decision (AD) scheme to determine to which functional type(s) it belongs. Experimental results show that Mem-ADSVM significantly outperforms state-of-the-art predictors in terms of identifying both membrane proteins and their multi-functional types. This paper also suggests that the two-layer prediction architecture is better than the one-layer for prediction performance. For reader׳s convenience, the Mem-ADSVM server is available online at http://bioinfo.eie.polyu.edu.hk/MemADSVMServer/.

  11. Improved lumped models for transient combined convective and radiative cooling of a two-layer spherical fuel element

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Alice Cunha da; Su, Jian, E-mail: alicecs@poli.ufrj.br, E-mail: sujian@nuclear.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    The High Temperature Gas cooled Reactor (HTGR) is a fourth generation thermal nuclear reactor, graphite-moderated and helium cooled. The HTGRs have important characteristics making essential the study of these reactors, as well as its fuel element. Examples of these are: high thermal efficiency,low operating costs and construction, passive safety attributes that allow implication of the respective plants. The Pebble Bed Modular Reactor (PBMR) is a HTGR with spherical fuel elements that named the reactor. This fuel element is composed by a particulate region with spherical inclusions, the fuel UO2 particles, dispersed in a graphite matrix and a convective heat transfer by Helium happens on the outer surface of the fuel element. In this work, the transient heat conduction in a spherical fuel element of a pebble-bed high temperature reactor was studied in a transient situation of combined convective and radiative cooling. Improved lumped parameter model was developed for the transient heat conduction in the two-layer composite sphere subjected to combined convective and radiative cooling. The improved lumped model was obtained through two-point Hermite approximations for integrals. Transient combined convective and radiative cooling of the two-layer spherical fuel element was analyzed to illustrate the applicability of the proposed lumped model, with respect to die rent values of the Biot number, the radiation-conduction parameter, the dimensionless thermal contact resistance, the dimensionless inner diameter and coating thickness, and the dimensionless thermal conductivity. It was shown by comparison with numerical solution of the original distributed parameter model that the improved lumped model, with H2,1/H1,1/H0,0 approximation yielded significant improvement of average temperature prediction over the classical lumped model. (author)

  12. Two-layer ZnO nanowire arrays: Fabrication and its photovoltaic property sensitized by CdSe and CdS quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Jingzhi [School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore); State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012 (China); Wang, Jianxiong; Sun, Xiaowei [School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 (Singapore)

    2015-09-01

    Two-layer ZnO nanowire arrays have been synthesized by a low temperature hydrothermal method. The two-layer structure enables the absorption of CdSe and CdS quantum dots (QDs) on different nanostructured layers, respectively. Solar cell based on the QD sensitized ZnO nanowire arrays is fabricated. Because sequential light adsorption of different sensitizers happens in two different layers, the photoanode can reduce the interaction possibility among different QDs and extend the absorption range, and result in improved photovoltaic properties. - Highlights: • Two-layer ZnO nanowire array has been synthesized by a low temperature hydrothermal. • A two-layer quantum dot sensitized ZnO nanowire array solar cell has been fabricated. • The structure can reduce interaction possibility among different quantum dots. • The structure can extend the range of light absorption.

  13. Fall prevention in nursing homes

    DEFF Research Database (Denmark)

    Andresen, Mette; Hauge, Johnny

    2006-01-01

    that the number of hospitalization after a fall injury will become an even greater task for the Danish hospitals, The aim of the study was to show if there is a relationship between physically frail elderly nursing home resident’s subjective evaluation of fall-risk and an objective evaluation of their balance....... Further, to suggest tools for fall prevention in nursing home settings on the basis of the results of this study and the literature. A quantitative method inspired by the survey method was used to give an overview of fall patterns, subjective and objective evaluations of fallrisk. Participants were 16...... physically frail elderly nursing home residents from three different nursing homes. Measures: a small staff-questionnaire about incidences and places where the participants had falling-episodes during a 12 month period, The Falls Effi cacy Scale Swedish version (FES(S)) and Berg Balance Scale (BBS) Results...

  14. Falling for Fall Reading Games: Great Stories for the Season

    Science.gov (United States)

    Maxwell, D. Jackson

    2004-01-01

    Literacy games are just another strategy in the ultimate goal to increase reading and overall student academic performance. Activities such as the Fall reading game, which focuses on the Fall season, which encourage reluctant readers to take the beginning steps toward developing the skills they would need to become accomplished readers are…

  15. High-Performanced Cathode with a Two-Layered R-P Structure for Intermediate Temperature Solid Oxide Fuel Cells.

    Science.gov (United States)

    Huan, Daoming; Wang, Zhiquan; Wang, Zhenbin; Peng, Ranran; Xia, Changrong; Lu, Yalin

    2016-02-01

    Driven by the mounting concerns on global warming and energy crisis, intermediate temperature solid-oxide fuel cells (IT-SOFCs) have attracted special attention for their high fuel efficiency, low toxic gas emission, and great fuel flexibility. A key obstacle to the practical operation of IT-SOFCs is their sluggish oxygen reduction reaction (ORR) kinetics. In this work, we applied a new two-layered Ruddlesden-Popper (R-P) oxide, Sr3Fe2O7-δ (SFO), as the material for oxygen ion conducting IT-SOFCs. Density functional theory calculation suggested that SFO has extremely low oxygen ion formation energy and considerable energy barrier for O(2-) diffusion. Unfortunately, the stable SrO surface of SFO was demonstrated to be inert to O2 adsorption and dissociation reaction, and thus restricts its catalytic activity toward ORR. Based on this observation, Co partially substituted SFO (SFCO) was then synthesized and applied to improve its surface vacancy concentration to accelerate the oxygen adsorptive reduction reaction rate. Electrochemical performance results suggested that the cell using the SFCO single phase cathode has a peak power density of 685 mW cm(-2) at 650 °C, about 15% higher than those when using LSCF cathode. Operating at 200 mA cm(-2), the new cell using SFCO is quite stable within the 100-h' test.

  16. Forced phase-locked states and information retrieval in a two-layer network of oscillatory neurons with directional connectivity

    Science.gov (United States)

    Kazantsev, Victor; Pimashkin, Alexey

    2007-09-01

    We propose two-layer architecture of associative memory oscillatory network with directional interlayer connectivity. The network is capable to store information in the form of phase-locked (in-phase and antiphase) oscillatory patterns. The first (input) layer takes an input pattern to be recognized and their units are unidirectionally connected with all units of the second (control) layer. The connection strengths are weighted using the Hebbian rule. The output (retrieved) patterns appear as forced-phase locked states of the control layer. The conditions are found and analytically expressed for pattern retrieval in response on incoming stimulus. It is shown that the system is capable to recover patterns with a certain level of distortions or noises in their profiles. The architecture is implemented with the Kuramoto phase model and using synaptically coupled neural oscillators with spikes. It is found that the spiking model is capable to retrieve patterns using the spiking phase that translates memorized patterns into the spiking phase shifts at different time scales.

  17. Spin torque driven dynamics of a coupled two-layer structure: Interplay between conservative and dissipative coupling

    Science.gov (United States)

    Romera, M.; Lacoste, B.; Ebels, U.; Buda-Prejbeanu, L. D.

    2016-09-01

    The general concepts of spin wave theory are adapted to the spin torque driven dynamics of a self-polarized system based on two layers coupled via interlayer exchange (conservative coupling) and mutual spin torque (dissipative coupling). An analytical description of the nonlinear dynamics is proposed and validated through numerical simulations. In contrast to the single layer model, the phase equation of the coupled system has a contribution coming from the dissipative part of the LLGS equation. It is shown that this is a major contribution to the frequency mandatory to describe well the most basic features of the dynamics of this coupled system. Using the proposed model a specific feature of coupled dynamics is addressed: the redshift to blueshift transition observed in the frequency current dependence of this kind of exchange coupled systems upon increasing the applied field. It is found that the blueshift regime can only occur in a region of field where the two linear eigenmodes contribute equally to the steady state mode (i.e., high mode hybridization). Finally, a general perturbed Hamiltonian equation for the coupled system is proposed.

  18. TargetCrys: protein crystallization prediction by fusing multi-view features with two-layered SVM.

    Science.gov (United States)

    Hu, Jun; Han, Ke; Li, Yang; Yang, Jing-Yu; Shen, Hong-Bin; Yu, Dong-Jun

    2016-11-01

    The accurate prediction of whether a protein will crystallize plays a crucial role in improving the success rate of protein crystallization projects. A common critical problem in the development of machine-learning-based protein crystallization predictors is how to effectively utilize protein features extracted from different views. In this study, we aimed to improve the efficiency of fusing multi-view protein features by proposing a new two-layered SVM (2L-SVM) which switches the feature-level fusion problem to a decision-level fusion problem: the SVMs in the 1st layer of the 2L-SVM are trained on each of the multi-view feature sets; then, the outputs of the 1st layer SVMs, which are the "intermediate" decisions made based on the respective feature sets, are further ensembled by a 2nd layer SVM. Based on the proposed 2L-SVM, we implemented a sequence-based protein crystallization predictor called TargetCrys. Experimental results on several benchmark datasets demonstrated the efficacy of the proposed 2L-SVM for fusing multi-view features. We also compared TargetCrys with existing sequence-based protein crystallization predictors and demonstrated that the proposed TargetCrys outperformed most of the existing predictors and is competitive with the state-of-the-art predictors. The TargetCrys webserver and datasets used in this study are freely available for academic use at: http://csbio.njust.edu.cn/bioinf/TargetCrys .

  19. A novel technique for chest drain removal using a two layer method with triclosan-coated sutures

    Science.gov (United States)

    Yokoyama, Yujiro; Nakagomi, Takahiro; Shikata, Daichi

    2017-01-01

    In thoracic surgery, a thoracic drain is always inserted after the surgical procedure. Repair of the wound after removal of the thoracic tube is performed postoperatively, but no universally standard methods currently exists for this tube removal. Here we report a technique using triclosan-coated sutures that is used in thoracic surgery in our hospital. There are several advantages of this technique. First, there is no need for stitches removal on follow-up. Second, it prevents the leakage of pleural exudate because of the tight two-layer sutures. In addition, it was observed to be superior in terms of both wound healing and cosmetic aspects, due to the layer-to-layer sutures. The use of triclosan-coated sutures helps prevent infection and empyema is quite unlikely to occur as the result of the tight ligating of the muscular layer using these sutures. We applied this method in 168 patients over a period of 24 months. There were no complications on removal of the chest tube such as infection, fluid leakage or opening of the surgical wound. PMID:28203426

  20. Diffraction of Oblique Water Waves by Small Uneven Channel-bed in a Two-layer Fluid

    Institute of Scientific and Technical Information of China (English)

    Smrutiranjan Mohapatra

    2014-01-01

    Obliquely incident water wave scattering by an uneven channel-bed in the form of a small bottom undulation in a two-layer fluid is investigated within the frame work of three-dimensional linear water wave theory. The upper fluid is assumed to be bounded above by a rigid lid, while the lower one is bounded below by a bottom surface having a small deformation and the channel is unbounded in the horizontal directions. Assuming irrotational motion, perturbation technique is employed to calculate the first-order corrections to the velocity potentials in the two fluids by using Fourier transform approximately, and also to calculate the reflection and transmission coefficients in terms of integrals involving the shape function representing the bottom deformation. Consideration of a patch of sinusoidal ripples shows that the reflection coefficient is an oscillatory function of the ratio of twice the component of the wave number along x-axis and the ripple wave number. When this ratio approaches one, the theory predicts a resonant interaction between the bed and interface, and the reflection coefficient becomes a multiple of the number of ripples. High reflection of incident wave energy occurs if this number is large.

  1. An analytical model for solute transport through a GCL-based two-layered liner considering biodegradation.

    Science.gov (United States)

    Guan, C; Xie, H J; Wang, Y Z; Chen, Y M; Jiang, Y S; Tang, X W

    2014-01-01

    An analytical model for solute advection and dispersion in a two-layered liner consisting of a geosynthetic clay liner (GCL) and a soil liner (SL) considering the effect of biodegradation was proposed. The analytical solution was derived by Laplace transformation and was validated over a range of parameters using the finite-layer method based software Pollute v7.0. Results show that if the half-life of the solute in GCL is larger than 1 year, the degradation in GCL can be neglected for solute transport in GCL/SL. When the half-life of GCL is less than 1 year, neglecting the effect of degradation in GCL on solute migration will result in a large difference of relative base concentration of GCL/SL (e.g., 32% for the case with half-life of 0.01 year). The 100-year solute base concentration can be reduced by a factor of 2.2 when the hydraulic conductivity of the SL was reduced by an order of magnitude. The 100-year base concentration was reduced by a factor of 155 when the half life of the contaminant in the SL was reduced by an order of magnitude. The effect of degradation is more important in approving the groundwater protection level than the hydraulic conductivity. The analytical solution can be used for experimental data fitting, verification of complicated numerical models and preliminary design of landfill liner systems.

  2. Multiresidue analysis of pesticides in vegetables and fruits using two-layered column with graphitized carbon and water absorbent polymer.

    Science.gov (United States)

    Obana, H; Akutsu, K; Okihashi, M; Hori, S

    2001-09-01

    A high-throughput multiresidue analysis of pesticides in non-fatty vegetables and fruits was developed. The method consisted of a single extraction and a single clean-up procedure. Food samples were extracted with ethyl acetate and the mixture of extract and food dregs were poured directly into the clean-up column. The clean-up column consisted of two layers of water-absorbent polymer (upper) and graphitized carbon (lower), which were packed in a reservoir (75 ml ) of a cartridge column. The polymer removed water in the extract while the carbon performed clean-up. In a recovery test, 110 pesticides were spiked and average recoveries were more than 95% from spinach and orange. Most pesticides were recovered in the range 70-115% with RSD usually < 10% for five experiments. The residue analyses were performed by the extraction of 12 pesticides from 13 samples. The two methods resulted in similar residue levels except chlorothalonil in celery, for which the result was lower with the proposed method. The results confirmed that the proposed method could be applied to monitoring of pesticide residue in foods.

  3. Diffraction of oblique water waves by small uneven channel-bed in a two-layer fluid

    Science.gov (United States)

    Mohapatra, Smrutiranjan

    2014-09-01

    Obliquely incident water wave scattering by an uneven channel-bed in the form of a small bottom undulation in a two-layer fluid is investigated within the frame work of three-dimensional linear water wave theory. The upper fluid is assumed to be bounded above by a rigid lid, while the lower one is bounded below by a bottom surface having a small deformation and the channel is unbounded in the horizontal directions. Assuming irrotational motion, perturbation technique is employed to calculate the first-order corrections to the velocity potentials in the two fluids by using Fourier transform approximately, and also to calculate the reflection and transmission coefficients in terms of integrals involving the shape function representing the bottom deformation. Consideration of a patch of sinusoidal ripples shows that the reflection coefficient is an oscillatory function of the ratio of twice the component of the wave number along x-axis and the ripple wave number. When this ratio approaches one, the theory predicts a resonant interaction between the bed and interface, and the reflection coefficient becomes a multiple of the number of ripples. High reflection of incident wave energy occurs if this number is large.

  4. Reflection of a plane wave from a two-layered seafloor with non-parallel interface between the layers.

    Science.gov (United States)

    Papadakis, Panagiotis I; Piperakis, George S; Kalogerakis, Michael A

    2015-02-01

    This work studies the reflection coefficient of a plane wave incident on a seafloor consisting of two layers (sediment and substrate), whose interface is linear but not parallel to the water-sediment interface. This is an extension of the well-established and studied reflection coefficient concept for seafloors with parallel layers. Moreover this study introduces the concept of the Coherent Reflection Coefficient (CRC) that extends the usual Rayleigh reflection coefficient definition not only at the water-sediment interface but inside the water column as well. The mathematical formulation of the CRC is derived and its numerical implementation is explained. Based on this implementation a numerical code is developed and incorporated-among other codes-in a user-friendly graphics toolbox that was built to facilitate CRC calculations. Numerical examples for realistic seafloors are presented and the derived results are compared to similar ones for parallel layers, indicating that even for small inclination angles the reflection coefficient difference between parallel and slanted interface layers is substantial, hence cannot be ignored. An imminent application of the extended seafloor model and the CRC introduced in this work is the enhancement of geophysics inversion schemes for the estimation of the seafloor parameters.

  5. Calculation of the outcomes of remodeling of arteries subjected to sustained hypertension using a 3D two-layered model.

    Science.gov (United States)

    Rachev, Alexander; Taylor, W Robert; Vito, Raymond P

    2013-07-01

    Arteries manifest a remodeling response to long-term alterations in arterial pressure and blood flow by changing geometry, structure, and composition through processes driven by perturbations of the local stresses in the vascular wall from their baseline values. The objective of this study is twofold--to develop a general method for calculating the remodeling responses of an artery considered as a two-layered tube; and to provide results for adaptive and maladaptive remodeling of a coronary artery. By formulating an inverse problem of vascular mechanics, the geometrical dimensions and mechanical properties of an artery are calculated from a prescribed deformed configuration, stress field, structural stiffness, and applied load. As an illustrative example we consider a human LAD coronary artery in both a perfect and incomplete adaptive response to a sustained step-wise change in pressure and a maladaptive response due to impaired remodeling of adventitia. The results obtained show that adventitia plays an important role in vascular mechanics when an artery is subjected to high arterial pressure. In addition to its well-known short term function of preventing over-inflation of an artery, it seems reasonable to accept that the manner by which adventitia remodels in response to a chronic increase in pressure is essential for preserving normal arterial function or may lead to an increased risk of developing vascular disorders.

  6. Study of an unitised bidirectional vanadium/air redox flow battery comprising a two-layered cathode

    Science.gov (United States)

    grosse Austing, Jan; Nunes Kirchner, Carolina; Hammer, Eva-Maria; Komsiyska, Lidiya; Wittstock, Gunther

    2015-01-01

    The performance of a unitised bidirectional vanadium/air redox flow battery (VARFB) is described. It contains a two-layered cathode consisting of a gas diffusion electrode (GDE) with Pt/C catalyst for discharging and of an IrO2 modified graphite felt for charging. A simple routine is shown for the modification of a graphite felt with IrO2. A maximum energy efficiency of 41.7% at a current density of 20 mA cm-2 as well as an average discharge power density of 34.6 mW cm-2 at 40 mA cm-2 were obtained for VARFB operation at room temperature with the novel cathode setup. A dynamic hydrogen electrode was used to monitor half cell potentials during operation allowing to quantify the contribution of the cathode to the overall performance of the VARFB. Four consecutive cycles revealed that crossover of vanadium ions took place and irreversible degradation processes within the reaction unit lead to a performance decrease.

  7. Tensoresistive Properties of Thin Film Systems Based on Ag and Co

    Directory of Open Access Journals (Sweden)

    I.M. Pazukha

    2012-10-01

    Full Text Available The results of research strain deformation properties of thin films Ag, Co and two-layers films Ag/Co in the range of deformation Δεl = 0-1 % were presented. The plastic deformation in Co layer caused a similar deformation in the entire film system, even if the strain range Ag layer is not reached the limits of the transition elastic/plastic deformation. The increasing of gauge factor value of two-layer systems in comparison with thin films Ag and Co appears as a result of electron interface scattering.

  8. Oxygen diffusion in bilayer polymer films

    DEFF Research Database (Denmark)

    Poulsen, Lars; Zebger, Ingo; Tofte, Jannik Pentti;

    2004-01-01

    Experiments to quantify oxygen diffusion have been performed on polymer samples in which a film of poly(ethylene-co-norbornene) was cast onto a film of polystyrene which, in turn, was cast onto an oxygen-impermeable substrate. In the technique employed, the time evolution of oxygen transport...... through the film of poly(ethylene-co-norbornene) and into the polystyrene film was monitored using the phosphorescence of singlet oxygen as a spectroscopic probe. To analyze the data, it was necessary to solve Fick's second law of diffusion for both polymer films. Tractable analytical and numerical...... solutions were obtained for the problem. Moreover, the numerical solution is sufficiently general that it can be used to simulate oxygen concentration profiles in films consisting of more than two layers. Data obtained from the bilayer films yield a diffusion coefficient for oxygen in poly...

  9. On the stability of discrete tripole, quadrupole, Thomson' vortex triangle and square in a two-layer/homogeneous rotating fluid

    Science.gov (United States)

    Kurakin, Leonid G.; Ostrovskaya, Irina V.; Sokolovskiy, Mikhail A.

    2016-05-01

    A two-layer quasigeostrophic model is considered in the f-plane approximation. The stability of a discrete axisymmetric vortex structure is analyzed for the case when the structure consists of a central vortex of arbitrary intensity Γ and two/three identical peripheral vortices. The identical vortices, each having a unit intensity, are uniformly distributed over a circle of radius R in a single layer. The central vortex lies either in the same or in another layer. The problem has three parameters ( R, Γ, α), where α is the difference between layer thicknesses. A limiting case of a homogeneous fluid is also considered. A limiting case of a homogeneous fluid is also considered. The theory of stability of steady-state motions of dynamic systems with a continuous symmetry group G is applied. The two definitions of stability used in the study are Routh stability and G-stability. The Routh stability is the stability of a one-parameter orbit of a steady-state rotation of a vortex multipole, and the G-stability is the stability of a three-parameter invariant set O G , formed by the orbits of a continuous family of steady-state rotations of a multipole. The problem of Routh stability is reduced to the problem of stability of a family of equilibria of a Hamiltonian system. The quadratic part of the Hamiltonian and the eigenvalues of the linearization matrix are studied analytically. The cases of zero total intensity of a tripole and a quadrupole are studied separately. Also, the Routh stability of a Thomson vortex triangle and square was proved at all possible values of problem parameters. The results of theoretical analysis are sustained by numerical calculations of vortex trajectories.

  10. Testing the two-layer model for correcting near-cloud reflectance enhancement using LES/SHDOM-simulated radiances

    Science.gov (United States)

    Wen, Guoyong; Marshak, Alexander; Várnai, Tamás.; Levy, Robert

    2016-08-01

    A transition zone exists between cloudy skies and clear sky; such that, clouds scatter solar radiation into clear-sky regions. From a satellite perspective, it appears that clouds enhance the radiation nearby. We seek a simple method to estimate this enhancement, since it is so computationally expensive to account for all three-dimensional (3-D) scattering processes. In previous studies, we developed a simple two-layer model (2LM) that estimated the radiation scattered via cloud-molecular interactions. Here we have developed a new model to account for cloud-surface interaction (CSI). We test the models by comparing to calculations provided by full 3-D radiative transfer simulations of realistic cloud scenes. For these scenes, the Moderate Resolution Imaging Spectroradiometer (MODIS)-like radiance fields were computed from the Spherical Harmonic Discrete Ordinate Method (SHDOM), based on a large number of cumulus fields simulated by the University of California, Los Angeles (UCLA) large eddy simulation (LES) model. We find that the original 2LM model that estimates cloud-air molecule interactions accounts for 64% of the total reflectance enhancement and the new model (2LM + CSI) that also includes cloud-surface interactions accounts for nearly 80%. We discuss the possibility of accounting for cloud-aerosol radiative interactions in 3-D cloud-induced reflectance enhancement, which may explain the remaining 20% of enhancements. Because these are simple models, these corrections can be applied to global satellite observations (e.g., MODIS) and help to reduce biases in aerosol and other clear-sky retrievals.

  11. Oblique Water Wave Scattering by Bottom Undulation in a Two-layer Fluid Flowing Through a Channel

    Institute of Scientific and Technical Information of China (English)

    Smrutiranjan Mohapatra; Swaroop Nandan Bora

    2012-01-01

    The problem of oblique wave (internal wave) propagation over a small deformation in a channel flow consisting of two layers was considered.The upper fluid was assumed to be bounded above by a rigid lid,which is an approximation for the free surface,and the lower one was bounded below by an impermeable bottom surface having a small deformation; the channel was unbounded in the horizontal directions.Assuming irrotational motion,the perturbation technique was employed to calculate the first-order corrections of the velocity potential in the two fluids by using Green's integral theorem suitably with the introduction of appropriate Green's functions.Those functions help in calculating the reflection and transmission coefficients in terms of integrals involving the shape function c(x) representing the bottom deformation.Three-dimensional linear water wave theory was utilized for formulating the relevant boundary value problem.Two special examples of bottom deformation were considered to validate the results.Consideration of a patch of sinusoidal ripples (having the same wave number) shows that the reflection coefficient is an oscillatory function of the ratio of twice the x-component of the wave number to the ripple wave number.When this ratio approaches one,the theory predicts a resonant interaction between the bed and the interface,and the reflection coefficient becomes a multiple of the number of tipples.High reflection of incident wave energy occurs if this number is large.Similar results were observed for a patch of sinusoidal tipples having different wave numbers.It was also observed that for small angles of incidence,the reflected energy is greater compared to other angles of incidence up to π / 4.These theoretical observations are supported by graphical results.

  12. A two-layer ONIOM study of thiophene cracking catalyzed by proton- and cation-exchanged FAU zeolite.

    Science.gov (United States)

    Sun, Yingxin; Mao, Xinfeng; Pei, Supeng

    2016-02-01

    A two-layer ONIOM study on the hydrodesulfurization mechanism of thiophene in H-FAU and M-FAU (M = Li(+), Na(+), and K(+)) has been carried out. The calculated results reveal that in H-FAU, for a unimolecular mechanism, the rate-determining step is hydrogenation of alkoxide intermediate. The assistance of H2O and H2S molecules does not reduce the difficulty of the C-S bond cracking step more effectively. A bimolecular hydrodesulfurization mechanism is more favorable due to the lower activation barriers. The rate-determining step is the formation of 2-methylthiophene, not the C-S bond cracking of thiophene. Moreover, the ring opening of thiophene is much easier to occur than the desulfurization step. A careful analysis of energetics indicates that H2S, propene, and methyl thiophene are the major products for the hydrodesulfurization process of thiophene over H-FAU zeolite, in good agreement with experimental findings. In M-FAU zeolites, both unimolecular and bimolecular cracking processes are difficult to occur because of the high energy barriers. Compared to the case on H-FAU, the metal cations on M-FAU increase the difficulty of occurrence of bimolecular polymerization and subsequent C-S bond cracking steps. Graphical abstract Hydrodesulfurization process of thiophene can take place in H-FAU zeolite. Two different mechanisms, unimolecular and bimolecular ones, have been proposed and evaluated in detail. The bimolecular mechanism is more favorable due to lower activation barrier as described in the picture above. Our calculated data indicate that H2S, propene, and methylthiophene are the major products, in good agreement with experimental observations. The effect of metal cations on the reaction mechanism is also investigated in this work.

  13. Synchronization and chaos control in a periodically forced quasi-geostrophic two-layer model of baroclinic instability

    Directory of Open Access Journals (Sweden)

    F. J. R. Eccles

    2006-01-01

    Full Text Available Cyclic forcing on many timescales is believed to have a significant effect on various quasi-periodic, geophysical phenomena such as El Niño, the Quasi-Biennial Oscillation, and glacial cycles. This variability has been investigated by numerous previous workers, in models ranging from simple energy balance constructions to full general circulation models. We present a numerical study in which periodic forcing is applied to a highly idealised, two-layer, quasi-geostrophic model on a β-plane. The bifurcation structure and (unforced behaviour of this particular model has been extensively examined by Lovegrove et al. (2001 and Lovegrove et al. (2002. We identify from their work three distinct regimes on which we perform our investigations: a steady, travelling wave regime, a quasi-periodic, modulated wave regime and a chaotic regime. In the travelling wave regime a nonlinear resonance is found. In the periodic regime, Arnol'd tongues, frequency locking and a Devil's staircase is seen for small amplitudes of forcing. As the forcing is increased the Arnol'd tongues undergo a period doubling route to chaos, and for larger forcings still, the parameter space we explored is dominated by either period 1 behaviour or chaotic behaviour. In the chaotic regime we extract unstable periodic orbits (UPOs and add the periodic forcing at periods corresponding to integer multiples of the UPO periods. We find regions of synchronization, similar to Arnol'd tongue behaviour but more skewed and centred approximately on these periods. The regions where chaos suppression took place are smaller than the synchronization regions, and are contained within them.

  14. Falls in elderly hemodialysis patients.

    Science.gov (United States)

    Abdel-Rahman, E M; Turgut, F; Turkmen, K; Balogun, R A

    2011-10-01

    The elderly, (age ≥ 65 years) hemodialysis (HD) patient population is growing rapidly across the world. The risk of accidental falls is very high in this patient population due to multiple factors which include aging, underlying renal disease and adverse events associated with HD treatments. Falls, the most common cause of fatal injury among elderly, not only increase morbidity and mortality, but also increase costs to the health system. Prediction of falls and interventions to prevent or minimize fall risk and associated complications will be a major step in helping these patients as well as decreasing financial and social burdens. Thus, it is vital to learn how to approach this important problem. In this review, we will summarize the epidemiology, risk factors, pathophysiology and complications of falls in elderly HD patients. We will also focus on available methods to assess and predict the patients at higher risk of falling and will provide recommendations for interventions to reduce the occurrence of falls in this population.

  15. Radar fall detectors: a comparison

    Science.gov (United States)

    Erol, Baris; Amin, Moeness; Ahmad, Fauzia; Boashash, Boualem

    2016-05-01

    Falls are a major cause of accidents in elderly people. Even simple falls can lead to severe injuries, and sometimes result in death. Doppler fall detection has drawn much attention in recent years. Micro-Doppler signatures play an important role for the Doppler-based radar systems. Numerous studies have demonstrated the offerings of micro-Doppler characteristics for fall detection. In this respect, a plethora of micro-Doppler signature features have been proposed, including those stemming from speech recognition and wavelet decomposition. In this work, we consider four different sets of features for fall detection. These can be categorized as spectrogram based features, wavelet based features, mel-frequency cepstrum coefficients, and power burst curve features. Support vector machine is employed as the classifier. Performance of the respective fall detectors is investigated using real data obtained with the same radar operating resources and under identical sensing conditions. For the considered data, the spectrogram based feature set is shown to provide superior fall detection performance.

  16. Three-dimensional linear instability in pressure-driven two-layer channel flow of a Newtonian and a Herschel-Bulkley fluid

    Science.gov (United States)

    Sahu, K. C.; Matar, O. K.

    2010-11-01

    The three-dimensional linear stability characteristics of pressure-driven two-layer channel flow are considered, wherein a Newtonian fluid layer overlies a layer of a Herschel-Bulkley fluid. We focus on the parameter ranges for which Squire's theorem for the two-layer Newtonian problem does not exist. The modified Orr-Sommerfeld and Squire equations in each layer are derived and solved using an efficient spectral collocation method. Our results demonstrate the presence of three-dimensional instabilities for situations where the square root of the viscosity ratio is larger than the thickness ratio of the two layers; these "interfacial" mode instabilities are also present when density stratification is destabilizing. These results may be of particular interest to researchers studying the transient growth and nonlinear stability of two-fluid non-Newtonian flows. We also show that the "shear" modes, which are present at sufficiently large Reynolds numbers, are most unstable to two-dimensional disturbances.

  17. SisFall: A Fall and Movement Dataset

    Science.gov (United States)

    Sucerquia, Angela; López, José David; Vargas-Bonilla, Jesús Francisco

    2017-01-01

    Research on fall and movement detection with wearable devices has witnessed promising growth. However, there are few publicly available datasets, all recorded with smartphones, which are insufficient for testing new proposals due to their absence of objective population, lack of performed activities, and limited information. Here, we present a dataset of falls and activities of daily living (ADLs) acquired with a self-developed device composed of two types of accelerometer and one gyroscope. It consists of 19 ADLs and 15 fall types performed by 23 young adults, 15 ADL types performed by 14 healthy and independent participants over 62 years old, and data from one participant of 60 years old that performed all ADLs and falls. These activities were selected based on a survey and a literature analysis. We test the dataset with widely used feature extraction and a simple to implement threshold based classification, achieving up to 96% of accuracy in fall detection. An individual activity analysis demonstrates that most errors coincide in a few number of activities where new approaches could be focused. Finally, validation tests with elderly people significantly reduced the fall detection performance of the tested features. This validates findings of other authors and encourages developing new strategies with this new dataset as the benchmark. PMID:28117691

  18. Theoretical research on enhancement of gain for Ni-like Ag 13.9 nm x-ray laser using a new two-layer target

    Institute of Scientific and Technical Information of China (English)

    Zhang Guo-Ping; Zhang Tan-Xin; Zheng Wu-Di; Qiao Xiu-Mei

    2007-01-01

    For experiments such as on Ni-like Ag x-ray laser, driven by 1ω laser, the gain region is only several nrn depth near the target surface, this paper proposes a new two-layer target, in which a thin layer (several nm depth) of silver is plated on the surface of some other materials. Furthermore, the Ni-like Ag 13.9 nm x-ray laser produced by three new kinds of two-layer target with CH, Al and Ge as foundation, was theoretically studied.

  19. Community College Estimated Growth: Fall 2010

    Science.gov (United States)

    Phillippe, Kent; Mullin, Christopher M.

    2011-01-01

    A survey from the American Association of Community Colleges (AACC) found that enrollment growth in fall 2010 slowed its pace at community colleges, increasing 3.2% from the previous year. This contrasts with more dramatic increases in recent years: more than 11% between fall 2008 and fall 2009, and nearly 17% between fall 2007 and fall 2009,…

  20. A theoretical, two-layer, reduced-gravity model for descending dense water flow on continental shelves/slopes

    Science.gov (United States)

    Wang, Jia; Ikeda, Moto; Saucier, Francois J.

    2003-05-01

    A theoretical, two-layer, reduced-gravity model for descending dense water flow on continental shelves/slopes has been developed to investigate the dynamics of bottom dense water plumes. The model is nonsteady state and includes vertical viscosity, the Coriolis force, and bottom friction. An integral solution rather than a perfect analytical expression is derived and, thus, the Simpson's 1/3 rule to approximate the integral is applied. At the very bottom, the dense water plume moves about 45° to the right (left) in the Northern (Southern) Hemisphere, looking downslope. From the bottom, the velocity vector rotates anticyclonically upward, indicating a bottom Ekman spiral that mimics the atmospheric Ekman boundary layer. The dense water within the bottom Ekman layer obeys a three-force balance, while the dense water above the bottom Ekman layer is governed by a two-force balance, which is a geostrophic flow with superimposed cycloidal inertial oscillations oriented from about 25° to 140° to the right (left) of the downslope direction in the Northern (Southern) Hemisphere. The transport within the bottom Ekman layer is directed about 60-70° to the right (left) of the downslope direction in the Northern (Southern) Hemisphere, forming an offshore (cross-isobath) transport in the absence of eddy flux and wind-forcing. The ratio of offshore transport to alongshore transport within the bottom Ekman layer is about 0.19 (19%), while the ratio above the bottom Ekman layer (i.e., geostrophic layer of the dense water) is only 3% (negligible compared to its alongshore transport), which, however, is equivalent in magnitude to its counterpart in the bottom Ekman layer if O(DE/h) ˜ 0.1 (where DE is the bottom Ekman layer thickness and h is the dense water layer thickness). In other words, the bottom Ekman layer and the geostrophic (dense) layer contribute equivalent dense water offshore (each contributes 50%). The magnitude of the descending dense water velocity depends

  1. Remediation of PCE-contaminated aquifer by an in situ two-layer biobarrier: laboratory batch and column studies.

    Science.gov (United States)

    Kao, C M; Chen, S C; Wang, J Y; Chen, Y L; Lee, S Z

    2003-01-01

    The industrial solvent tetrachloroethylene (PCE) is among the most ubiquitous chlorinated compounds found in groundwater contamination. The objective of this study was to develop an in situ two-layer biobarrier system consisting of an organic-releasing material layer followed by an oxygen-releasing material layer. The organic-releasing material, which contained sludge cakes from a domestic wastewater treatment plant, is able to release biodegradable organics continuously. The oxygen-releasing material, which contained calcium peroxide, is able to release oxygen continuously upon contact with water. The first organic-releasing material layer was to supply organics (primary substrates) to reductively dechlorinate PCE in situ. The second oxygen-releasing material layer was to release oxygen to aerobic biodegrade or cometabolize PCE degradation byproducts from the first anaerobic layer. Batch experiments were conducted to design and identify the components of the organic and oxygen-releasing materials, and evaluate the organic substrate (presented as chemical oxygen demand (COD) equivalent) and oxygen release rates from the organic-releasing material and oxygen-releasing materials, respectively. The observed oxygen and COD release rates were approximately 0.0368 and 0.0416 mg/d/g of material, respectively. A laboratory-scale column experiment was then conducted to evaluate the feasibility of this proposed system for the bioremediation of PCE-contaminated groundwater. This system was performed using a series of continuous-flow glass columns including a soil column, an organic-releasing material column, two consecutive soil columns, and an oxygen-releasing material column, followed by two other consecutive soil columns. Anaerobic acclimated sludges were inoculated in the first four columns, and aerobic acclimated sludges were inoculated in the last three columns to provide microbial consortia for contaminant biodegradation. Simulated PCE-contaminated groundwater with a

  2. How Can Older Adults Prevent Falls?

    Science.gov (United States)

    ... Talk to your doctor about whether you have osteoporosis. Read More "Preventing Falls" Articles Preventing Falls / Great Help for Older Adults / How Can Older Adults Prevent Falls? / Home Improvements ...

  3. Preventing Falls: Great Help for Older Americans

    Science.gov (United States)

    ... of this page please turn JavaScript on. Feature: Falls and Older Adults Great Help for Older Americans ... on National Pepper Center website. Read More "Preventing Falls" Articles Preventing Falls / Great Help for Older Adults / ...

  4. Falls Among Older Adults: An Overview

    Science.gov (United States)

    ... health care providers. Learn More Important Facts about Falls Recommend on Facebook Tweet Share Compartir Each year, ... once doubles your chances of falling again. 2 Falls Are Serious and Costly One out of five ...

  5. Local Falling Film Flow Study of Mesh Corrugated Packing Used in the Separation of Stable Isotope 13 C%稳定同位素13 C分离用高效丝网波纹填料表面降膜流动研究

    Institute of Scientific and Technical Information of China (English)

    田叶盛; 李虎林; 姜永悦; 龙磊; 吉永喆; 蔡扬

    2016-01-01

    The separation coefficient of carbon isotopes is small ,high-efficiency struc-tured packing should be used in the separation of 13 C . So the self-developed high-efficiency structured packing PACK-13 C was put forward .By means of computational fluid dynamics (CFD) ,a local falling film flow of mesh corrugated packing PACK-13 C with the gas phase counter-current model using the volume of fluid (VOF) was presen-ted .CO(l)-CO(g) was selected to be the simulation mixtures .Based on the simulated results ,the influences of the plate structures and the mesh sizes on the film flow were investigated .Based on the gas-liquid interface tracking timely ,the influence of interface fluctuation on the mass transfer efficiency was also investigated . The results showed that improving the wall structures to enhance the interface fluctuation was the effective way to strengthen the mass-transfer efficiency .The method of local falling film flow study could be applied to research the multi-scale flow and mass-transfer behavior of the packing w hich provide some theoretical guidance about the optimization of the packing ’s structures .%由于碳同位素分离系数小,分离难度大,需要采用高效规整填料实现13 C的分离。本文通过计算流体力学(CFD)数值模拟研究,采用流体体积函数(VOF)方法,研制了用于13 C分离的高比表面积丝网波纹规整填料(PACK-13C),建立了PACK-13C填料表面伴随有气相逆流的局部液体降膜流动模型,选用CO(l)-CO(g)为模拟计算物系,考察了板面结构、丝网目数等因素对液膜流动的影响,并对填料表面气液相界面进行追踪,探究了气液相界面波动对传质效率的影响,研究表明,改善填料壁面结构能够增强气液相界面波动,可以实现强化传质过程。填料表面局部降膜流动的研究方法,可应用于填料气液传质过程中涉及的多尺度流动及传质现象的可视化研究,

  6. Investigating sources of measured forest-atmosphere ammonia fluxes using two-layer bi-directional modelling

    DEFF Research Database (Denmark)

    Hansen, K.; Personne, E.; Skjøth, C.A.

    2017-01-01

    with a coupled photosynthesis-stomatal conductance model to represent seasonal variation in canopy physiological activity for simulating both net ecosystem CO2 exchange rates (R2=0.77 for MMSF and R2=0.84 for DK-Sor) and atmospheric NH3 fluxes (R2=0.43 for MMSF and R2=0.60 for DK-Sor). A scaling of the ground...... explain the daytime flux observations well, and it is hypothesized that cuticular desorption is responsible for the observed NH3 emissions at night. During leaf fall in DK-Sor, ground fluxes dominate the NH3 flux with a mean emission rate of 150ng NH3-N m−2s−1. This study shows that forests potentially...... comprise a natural source of NH3 to the atmosphere, and that it is crucial to take into account the bi-directional exchange processes related to both the stomatal, cuticular and ground layer pathways in order to realistically simulate forest–atmosphere fluxes of NH3....

  7. A two Layer Convecting Mantle With Exchange : A Unified Model Based on Geochemical, Seismic and Heat Flow Observations

    Science.gov (United States)

    Allègre, C. J.; Jaupart, C.; Nolet, G.

    2007-12-01

    -penetrating slabs as emphasized by Fukao and al.(2001) and the recent observation of the large energy spectrum differences at 670 km depth (Gu and al., 2006). We discuss the problem of return flow, which is crucial for both energy budget and convection regime. The recent work on plume by Montelli and al. (2004, 2006) shows the existence of broad plumes in the lower mantle and thin plumes in the upper mantle. d) The estimate of heat flow coming from the lower mantle of 35-32 TW. The work of Davies(1990) and Sleep(1992) shows clearly that this transfer is not the result of plumes reaching the surface, because they correspond at most to 3TW. At the reverse the estimated heat flow carried by the lower mantle plumes is much higher (Nolet and al., 2006). We also discuss the heat flow paradox to explain a Urey ratio of 0.4 with whole mantle convection. In conclusion, we propose mantle with two layers convecting separately but with some exchange of matter, this global exchange corresponding to 1.1024kg since 4.4 Gy. Plume genesis is a two-stage process. Lower mantle plumes heat the Mesosphere boundary layer generating second generation plumes which reach the surface (Allègre and Turcotte; 1983; Allègre, 1987). In the upper mantle itself, we have to distinguish between a vigorously convecting asthenosphere and a sluggish convecting transition zone, both convecting in same cells.

  8. Catching a Falling Star

    Science.gov (United States)

    2004-07-01

    . Comets are another important source of meteoroids and perhaps the most spectacular. After many visits near the Sun, a comet "dirty-snowball" nucleus of ice and dust decays and fragments, leaving a trail of meteoroids along its orbit. Some "meteoroid streams" cross the earth's orbit and when our planet passes through them, some of these particles will enter the atmosphere. The outcome is a meteor shower - the most famous being the "Perseids" in the month of August [2] and the "Leonids" in November. Thus, although meteors are referred to as "shooting" or "falling stars" in many languages, they are of a very different nature. More information The research presented in this paper is published in the journal Meteoritics and Planetary Science, Vol. 39, Nr. 4, p. 1, 2004 ("Spectroscopic anatomy of a meteor trail cross section with the ESO Very Large Telescope", by P. Jenniskens et al.). Notes [1] The team is composed of Peter Jenniskens (SETI Institute, USA), Emmanuël Jehin (ESO), Remi Cabanac (Pontificia Universidad Catolica de Chile), Christophe Laux (Ecole Centrale de Paris, France), and Iain Boyd (University of Michigan, USA). [2] The maximum of the Perseids is expected on August 12 after sunset and should be easily seen.

  9. [Accidental falls in the elderly].

    Science.gov (United States)

    Heinimann, Niklas B; Kressig, Reto W

    2014-06-18

    Falls in the elderly are common with consecutive high mortality and morbidity. Recent consecutive data focus on identification and therapy of intrinsic risk factors. Sarcopenia, imbalance and gait disorders represent the major risk factors. Sarcopenia is caused by a disequilibrium of protein synthesis and breakdown, probably in consequence of age-related changes in protein metabolism. Protein supplements in combination with strength training shows the best benefit. Disorders in balance and gait are caused by age-related or pathologic changes in a complex regulation system of gait. The individual fall risk correlates with the gait variability and even increases with bad dual task performance. Activities with high requirements of attention and body awareness are the most effective prevention for falls in the elderly (-50%).

  10. The stability of two layer dielectric-electrolyte micro-flow subjected to an external electric field

    Science.gov (United States)

    Demekhin, E. A.; Ganchenko, G. S.; Navarkar, A.; Amiroudine, S.

    2016-09-01

    The two-phase microflow of conductive (electrolyte) and non-conductive (dielectric) viscous liquids bounded by two solid walls in an external electric field is scrutinized. The lower solid wall, which is adjoined to the electrolyte, is a charged dielectric surface; the upper wall which bounds the dielectric is insulated. The problem has a steady one-dimensional (1D) solution. The theoretical results for a plug-like velocity profile are successfully compared with available theoretical and experimental data from the literature. The linear stability of the steady-state flow is investigated numerically with spectral Galerkin's method for solving linearized eigenvalue problem. This method was successfully applied for related problem of electroosmosis of ultrathin film. The numerical analysis provides insights on the coexistence of long and short-wave instabilities. The influence of control parameters such as the ratio of the viscosities of both liquids and the ratio of the channel heights on the stability of one-dimensional flow was investigated for different values of external electric field. The influence of an external pressure gradient on the flow stability is also investigated. The experimental facts established by other authors, according to which the system destabilizes if the electroosmotic flow is oppositely directed to the external pressure gradient, is confirmed in this work. Otherwise stabilization takes place.

  11. Falls in Parkinson's disease and Huntington's disease

    NARCIS (Netherlands)

    Grimbergen, Yvette Anna Maria

    2012-01-01

    Falls in Parkinson’s (PD) and Huntington’s disease (HD) are common. 50 % of moderately affected PD patients sustained two or more falls during a prospective follow-up of 6 months. During a 3 month period 40 % of HD patients reported one or more fall. Many falls resulted in minor injuries and 42 % of

  12. Falling: should one blame the heart?

    NARCIS (Netherlands)

    Jansen, S.

    2015-01-01

    Approximately 30% of people aged 65 and older suffer a fall each year; one in five of these falls will lead to significant injury. As the world’s ageing population increases, healthcare costs associated with falls are only expected to rise. It is estimated that over a third of falls may be preventab

  13. Falls prevention for the elderly.

    Science.gov (United States)

    Balzer, Katrin; Bremer, Martina; Schramm, Susanne; Lühmann, Dagmar; Raspe, Heiner

    2012-01-01

    An ageing population, a growing prevalence of chronic diseases and limited financial resources for health care underpin the importance of prevention of disabling health disorders and care dependency in the elderly. A wide variety of measures is generally available for the prevention of falls and fall-related injuries. The spectrum ranges from diagnostic procedures for identifying individuals at risk of falling to complex interventions for the removal or reduction of identified risk factors. However, the clinical and economic effectiveness of the majority of recommended strategies for fall prevention is unclear. Against this background, the literature analyses in this HTA report aim to support decision-making for effective and efficient fall prevention. The pivotal research question addresses the effectiveness of single interventions and complex programmes for the prevention of falls and fall-related injuries. The target population are the elderly (> 60 years), living in their own housing or in long term care facilities. Further research questions refer to the cost-effectiveness of fall prevention measures, and their ethical, social and legal implications. Systematic literature searches were performed in 31 databases covering the publication period from January 2003 to January 2010. While the effectiveness of interventions is solely assessed on the basis of randomised controlled trials (RCT), the assessment of the effectiveness of diagnostic procedures also considers prospective accuracy studies. In order to clarify social, ethical and legal aspects all studies deemed relevant with regard to content were taken into consideration, irrespective of their study design. Study selection and critical appraisal were conducted by two independent assessors. Due to clinical heterogeneity of the studies no meta-analyses were performed. Out of 12,000 references retrieved by literature searches, 184 meet the inclusion criteria. However, to a variable degree the validity of their

  14. Falls prevention for the elderly

    Directory of Open Access Journals (Sweden)

    Dagmar Lühmann

    2012-04-01

    Full Text Available Background: An ageing population, a growing prevalence of chronic diseases and limited financial resources for health care underpin the importance of prevention of disabling health disorders and care dependency in the elderly. A wide variety of measures is generally available for the prevention of falls and fall-related injuries. The spectrum ranges from diagnostic procedures for identifying individuals at risk of falling to complex interventions for the removal or reduction of identified risk factors. However, the clinical and economic effectiveness of the majority of recommended strategies for fall prevention is unclear. Against this background, the literature analyses in this HTA report aim to support decision-making for effective and efficient fall prevention.Research questions: The pivotal research question addresses the effectiveness of single interventions and complex programmes for the prevention of falls and fall-related injuries. The target population are the elderly (> 60 years, living in their own housing or in long term care facilities. Further research questions refer to the cost-effectiveness of fall prevention measures, and their ethical, social and legal implications. Methods: Systematic literature searches were performed in 31 databases covering the publication period from January 2003 to January 2010. While the effectiveness of interventions is solely assessed on the basis of randomised controlled trials (RCT, the assessment of the effectiveness of diagnostic procedures also considers prospective accuracy studies. In order to clarify social, ethical and legal aspects all studies deemed relevant with regard to content were taken into consideration, irrespective of their study design. Study selection and critical appraisal were conducted by two independent assessors. Due to clinical heterogeneity of the studies no meta-analyses were performed.Results: Out of 12,000 references retrieved by literature searches, 184 meet the

  15. A Successful ED Fall Risk Program Using the KINDER 1 Fall RiskAssessment Tool.

    Science.gov (United States)

    Townsend, Ann B; Valle-Ortiz, Marisol; Sansweet, Tracy

    2016-11-01

    Emergency nurses did not perform falls risk assessments routinely on our ED patients; the instrument used was aimed at inpatients. We identified a need to revise fall assessment practices specific to our emergency department. The purpose of the performance improvement project was to reduce ED falls and evaluate the use of an ED-specific fall risk tool, the KINDER 1 Fall Risk Assessment. The plan was to establish fall risk assessment practices at point of ED entry and to decrease total falls.

  16. Chinua Achebe's Things Fall Apart:

    African Journals Online (AJOL)

    Chinua Achebe's famous novel, Things Fall Apart (TFA), is an extended reductio ad .... Okonkwo's “whole life was dominated by fear, the fear of failure and of weakness. ..... tural ideals and values characteristic of civilized societies on common ...

  17. Fall Armyworm in the Southeast

    Science.gov (United States)

    Two separate experiments testing fall armyworm (Spodoptera frugiperda) migration patterns were set up in the southeastern U.S. in 2012. Previous results showed that moths from progeny of overwintering populations from south Texas were found west of the Chattahoochee-Flint-Apalachicola river basin, ...

  18. Student Transfer Matrix, Fall 1992.

    Science.gov (United States)

    Oklahoma State Regents for Higher Education, Oklahoma City.

    Comprised primarily of data matrices, this report provides information on students transferring from Oklahoma public and private post-secondary institutions to other public and private post-secondary institutions in the state in fall 1992. The report consists of nine sections. Section I provides an aggregate flow of all students in the state,…

  19. Finding Rising and Falling Words

    NARCIS (Netherlands)

    Tjong Kim Sang, E.

    2016-01-01

    We examine two different methods for finding rising words (among which neologisms) and falling words (among which archaisms) in decades of magazine texts (millions of words) and in years of tweets (billions of words): one based on correlation coefficients of relative frequencies and time, and one

  20. [Violence Profiles for Fall Programming.

    Science.gov (United States)

    National Citizens Committee for Broadcasting, Washington, DC.

    This document presented by the National Citizens' Committee for Broadcasting at a 1976 press conference provides an assortment of materials concerned with violence in television. Among the materials included are "Who Sponsors the New Fall Violence?" by Nicholas Johnson, a description of and rationale for the study of advertisers who sponsor…

  1. NOVA Fall 2000 Teacher's Guide.

    Science.gov (United States)

    Ransick, Kristina; Rosene, Dale; Sammons, Fran Lyons; Sammons, James

    This teacher's guide complements six programs that aired on the Public Broadcasting System (PBS) in the fall of 2000. Programs include: (1) "Lincoln's Secret Weapon"; (2) "Hitler's Lost Sub"; (3) "Runaway Universe"; (4) "Garden of Eden"; (5) "Dying to Be Thin"; and (6) "Japan's Secret…

  2. Film Reviews.

    Science.gov (United States)

    Lance, Larry M.; Atwater, Lynn

    1987-01-01

    Reviews four Human Sexuality films and videos. These are: "Personal Decisions" (Planned Parenthood Federation of America, 1985); "The Touch Film" (Sterling Production, 1986); "Rethinking Rape" (Film Distribution Center, 1985); "Not A Love Story" (National Film Board of Canada, 1981). (AEM)

  3. Creating and controlling overlap in two-layer networks. Application to a mean-field SIS epidemic model with awareness dissemination

    CERN Document Server

    Juher, David

    2015-01-01

    We study the properties of the potential overlap between two networks $A,B$ sharing the same set of $N$ nodes (a two-layer network) whose respective degree distributions $p_A(k), p_B(k)$ are given. Defining the overlap coefficient $\\alpha$ as the Jaccard index, we derive upper bounds for the minimum and maximum overlap coefficient in terms of $p_A(k)$, $p_B(k)$ and $N$. We also present an algorithm based on cross-rewiring of links to obtain a two-layer network with any prescribed $\\alpha$ inside the permitted range. Finally, to illustrate the importance of the overlap for the dynamics of interacting contagious processes, we derive a mean-field model for the spread of an SIS epidemic with awareness against infection over a two-layer network, containing $\\alpha$ as a parameter. A simple analytical relationship between $\\alpha$ and the basic reproduction number follows. Stochastic simulations are presented to assess the accuracy of the upper bounds of $\\alpha$ and the predictions of the mean-field epidemic model...

  4. Unconventional but tunable phase transition above the percolation threshold by two-layer conduction in electroless-deposited Au nanofeatures on silicon substrate.

    Science.gov (United States)

    Lee, Seung-Hoon; Shin, Muncheol; Hwang, Seongpil; Jang, Jae-Won

    2015-12-18

    Previous research has shown that disorder, dislocation, and carrier concentration are the main factors impacting transitions in the traditional metal-insulator transition (MIT) and metal-semiconductor transition (MST). In this study, it is demonstrated that a non-traditional metal-semiconductor transition governed by two-layer conduction is possible by tuning the conducting channel of one layer of the two-layer conduction system. By means of the electroless deposition method we produced Au nanofeatures (AuNFs) on p-type silicon (p-Si) as the two-layer conduction system, controlling AuNF coverage (Au%) below and above the percolation threshold (p c). Even when the AuNF coverage percentage is larger than p c, the resistivities of the AuNFs on p-Si show MST as the temperature increases. To demonstrate this finding, we present a conduction model based upon two predominant parallel conductions by AuNFs and p-Si in the present paper. In the results, we show how the temperature of the MST (T MST) is tuned from 145 to 232 K as Au% is changed from 82.7 to 54.3%.

  5. Optimisation on the two-layer stack gamma detectors of CsI(Tl) coupled with a pin photodiode for non-destructive testing.

    Science.gov (United States)

    Bai, Jin Hyoung; Whang, Joo Ho

    2011-07-01

    This paper proposed the two-layer stack scintillator-coupled photodiode detector to improve the measurement accuracy of the gamma-ray scanning. Both MCNPX and DETECT97 code were used to design the detector. The two manufactured two-layer stack gamma detectors were used to measure the density profile of the distillation column of the radiographic non-intrusive process diagnostic area. To compare the measurement accuracy of the density profile through the non-destructive transmission test, the relative error of the four fluids used for the process diagnostics was analysed. To summarise the measurement results with regard to the relative error of the NaI(Tl) detector and the manufactured detector by material as well as the total relative error, the total relative error of the NaI(Tl) detector was about 15.7 %, whereas that of the two-layer stack CsI(Tl) with photodiode detectors were about 5 %. This paper confirmed that the measurement accuracy of the detector proposed was improved by about three times as compared with the NaI(Tl) detector mostly used for non-destructive testing.

  6. Person-Centered Fall Risk Awareness Perspectives: Clinical Correlates and Fall Risk.

    Science.gov (United States)

    Verghese, Joe

    2016-12-01

    To identify clinical correlates of person-centered fall risk awareness and their validity for predicting falls. Prospective cohort study. Community. Ambulatory community-dwelling older adults without dementia (N = 316; mean age 78, 55% female). Fall risk awareness was assessed using a two-item questionnaire that asked participants about overall likelihood of someone in their age group having a fall and their own personal risk of falling over the next 12 months. Incident falls were recorded over study follow-up. Fifty-three participants (16.8%) responded positively to the first fall risk awareness question about being likely to have a fall in the next 12 months, and 100 (31.6%) reported being at personal risk of falling over the next 12 months. There was only fair correlation (κ = 0.370) between responses on the two questions. Prior falls and depressive symptoms were associated with positive responses on both fall risk awareness questions. Age and other established fall risk factors were not associated with responses on either fall risk awareness question. The fall risk awareness questionnaire did not predict incident falls or injurious falls. Fall risk awareness is low in older adults. Although person-centered fall risk awareness is not predictive of falls, subjective risk perceptions should be considered when designing fall preventive strategies because they may influence participation and behaviors. © 2016, Copyright the Author Journal compilation © 2016, The American Geriatrics Society.

  7. Watch Out for Falling Plasma

    Science.gov (United States)

    Kohler, Susanna

    2016-12-01

    The path taken by the falling fragment in the June 2011 event. [Adapted from Petralia et al. 2016]Sometimes plasma emitted from the Sun doesnt escape into space, but instead comes crashing back down to the solar surface. What can observations and models of this process tell us about how the plasma falls and the local conditions on the Sun?Fallback from a FlareOn 7 June 2011, an M-class flare erupted from the solar surface. As the Solar Dynamics Observatorys Atmospheric Imaging Assembly looked on, plasma fragments from the flare arced away from the Sun and then fell back to the surface.Some fragments fell back where the Suns magnetic field was weak, returning directly to the surface. But others fell within active regions, where they crashed into the Suns magnetic field lines, brightening the channels and funneling along them through the dense corona and back to the Suns surface.The authors model of the falling blobs at several different times in their simulation. The blobs get disrupted when they encounter the field lines, and are then funneled along the channels to the solar surface. [Adapted from Petralia et al. 2016]This sort of flare and fall-back event is a common occurrence with the Sun, and SDOs observations of the June 2011 event present an excellent opportunity to understand the process better. A team of scientists led by Antonino Petralia (University of Palermo, Italy and INAF-OAPA) modeled this event in an effort to learn more about how the falling plasma interacts with strong magnetic fields above the solar surface.Magnetic Fields as GuidesPetralia and collaborators used three-dimensional magnetohydrodynamical modeling to attempt to reproduce the observations of this event. They simulated blobs of plasma as they fall back to the solar surface and interact with magnetic field lines over a range of different conditions.The team found that only simulations that assume a relatively strong magnetic field resulted in the blobs funneling along a channel to the

  8. Mechanical properties of micron and nanodimentional metal films

    Directory of Open Access Journals (Sweden)

    I.Yu. Protsenko

    2010-01-01

    Full Text Available The mechanical and strain resistivity properties data for bulk condensates and nanodimentional films at the elastic and plastic deformation was analyzed. The experimental results of strain resistivity properties of one-layer (Fe, Cr, Pd and Pt and two-layer (Fe/Cr, Cu/Cr and Pd/Fe films, in particular, dependence of the deformation at the transition from elastic to plastic deformation from thickness was presented.

  9. Stabilising falling liquid film flows using feedback control

    CERN Document Server

    Thompson, Alice B; Pavliotis, Grigorios A; Papageorgiou, Demetrios T

    2015-01-01

    The flow of a fluid layer with one interface exposed to the air and the other an inclined planar wall becomes unstable due to inertial effects when the fluid layer is sufficiently thick or the slope sufficiently steep. This free surface flow of a single fluid layer has industrial applications including coating and heat transfer, which benefit from smooth and wavy interfaces, respectively. Here we discuss how the dynamics of the system are altered by introducing deliberately spatially-varying or time-dependent perturbations via the injection and suction of fluid through the wall. We find that injection and suction is a remarkably effective control mechanism: the controls can be used to drive the system towards arbitrary steady states and travelling waves, and the qualitative effects are independent of the details of the flow modelling. Furthermore, the system can still be successfully controlled even if the feedback must be applied via a set of localised actuators, and only a small number of system observation...

  10. Osteoarthritis and falls in the older person.

    Science.gov (United States)

    Ng, Chin Teck; Tan, Maw Pin

    2013-09-01

    Osteoarthritis and falls are common conditions affecting older individuals which are associated with disability and escalating health expenditure. It has been widely assumed that osteoarthritis is an established risk factor for falls in older people. The relationship between osteoarthritis and falls has, quite surprisingly, not been adequately elucidated, and published reports have been conflicting. Our review of the existing literature has found limited evidence supporting the current assumption that the presence of osteoarthritis is associated with increased risk of falls with suggestions that osteoarthritis may actually be protective against falls related fractures. In addition, joint arthroplasty appears to increase the risk of falls in individuals with osteoarthritis.

  11. What Are Ways to Prevent Falls and Related Fractures?

    Science.gov (United States)

    ... Resources Preventing Falls and Fractures Osteoporosis and Falls Osteoporosis and Falls (繁體中文) Partner Resources Falls and Fractures (NIA) Falls and Older Adults (NIH Senior Health) Caídas y fracturas (NIA) Director’s ...

  12. Associated Factors for Falls, Recurrent Falls, and Injurious Falls in Aged Men Living in Taiwan Veterans Homes

    Directory of Open Access Journals (Sweden)

    Yan-Chiou Ku

    2013-06-01

    Conclusion: This study demonstrated that the advanced age, depression status, stroke, gouty arthritis, and cataract are independent variables for predicting falls; depression is the only clinical factor capable of predicting the recurrent falls. These variables were potential targets for effective prevention of falls.

  13. A simple strategy for fall events detection

    KAUST Repository

    Harrou, Fouzi

    2017-01-20

    The paper concerns the detection of fall events based on human silhouette shape variations. The detection of fall events is addressed from the statistical point of view as an anomaly detection problem. Specifically, the paper investigates the multivariate exponentially weighted moving average (MEWMA) control chart to detect fall events. Towards this end, a set of ratios for five partial occupancy areas of the human body for each frame are collected and used as the input data to MEWMA chart. The MEWMA fall detection scheme has been successfully applied to two publicly available fall detection databases, the UR fall detection dataset (URFD) and the fall detection dataset (FDD). The monitoring strategy developed was able to provide early alert mechanisms in the event of fall situations.

  14. Falls Prevention: Unique to Older Adults

    Science.gov (United States)

    ... our e-newsletter! Aging & Health A to Z Falls Prevention Unique to Older Adults This section provides ... and Muscle Strengthening Exercises As part of your fall prevention program, you should follow an exercise program ...

  15. A replication study for genome-wide gene expression levels in two layer lines elucidates differentially expressed genes of pathways involved in bone remodeling and immune responsiveness.

    Directory of Open Access Journals (Sweden)

    Christin Habig

    Full Text Available The current replication study confirmed significant differences in gene expression profiles of the cerebrum among the two commercial layer lines Lohmann Selected Leghorn (LSL and Lohmann Brown (LB. Microarray analyses were performed for 30 LSL and another 30 LB laying hens kept in the small group housing system Eurovent German. A total of 14,103 microarray probe sets using customized Affymetrix ChiGene-1_0-st Arrays with 20,399 probe sets were differentially expressed among the two layer lines LSL and LB (FDR adjusted P-value <0.05. An at least 2-fold change in expression levels could be observed for 388 of these probe sets. In LSL, 214 of the 388 probe sets were down- and 174 were up-regulated and vice versa for the LB layer line. Among the 174 up-regulated probe sets in LSL, we identified 51 significantly enriched Gene ontology (GO terms of the biological process category. A total of 63 enriched GO-terms could be identified for the 214 down-regulated probe sets of the layer line LSL. We identified nine genes significantly differentially expressed between the two layer lines in both microarray experiments. These genes play a crucial role in protection of neuronal cells from oxidative stress, bone mineral density and immune response among the two layer lines LSL and LB. Thus, the different regulation of these genes may significantly contribute to phenotypic trait differences among these layer lines. In conclusion, these novel findings provide a basis for further research to improve animal welfare in laying hens and these layer lines may be of general interest as an animal model.

  16. Heat absorbtion by earth coil systems placed in two layers in one trench. [Heat pumps]. Varmeoptagelse fra jordslanger i to lag i samme grav

    Energy Technology Data Exchange (ETDEWEB)

    Willumsen, O.

    1989-01-01

    The aim of the project is to evaluate the performance of a new technique of installing earth coil systems for heat pumps. In order to reduce the costs of an efficient heat absorber, two coils were placed in the same trench in two different levels, generally in a depth of 0.7 and 1.1 metres. Usually the total pipe length was increased with 20 - 30% compared to the one-layer design. The digging expences, however, were still smaller than those of the one-layer design. The evaluation is based on measurements on 4 heat pump installations using the two-layer concept, where the extracted heat energy from the higher and lower earth coils were metered individually on a monthly basis. Furthermore, the in- and outlet temperature of the coils and the energy comsumption of the heat pump was measured. The main conclusions of the project are: - A two-layer design leads to a slightly cheaper earth coil. The performance of the earth coil is not negatively affected by this technique, provided that the vertical distance between the coils is at least 0.4 metres at any place. - Two-layer coils may be designed with the same total length as used in one-layer coils - which means half the trench length. This design gives a more intensive exploitation of the available soil area, without decreasing the performance of the heat pump. - The disadvantage of the technique is an increasing risk of earth elevation due to freezing. This risk should be minimized by keeping a minimum distance of 0.40 meters between the individual pipes and thermal insulation if more than two pipes are placed near to each other. (AB).

  17. 双层界面重磁联合反演方法研究%Joint inversion of gravity and magnetic data for a two-layer model

    Institute of Scientific and Technical Information of China (English)

    江凡; 吴健生; 王家林

    2008-01-01

    Based on the synchronous joint gravity and magnetic inversion of single interface by Pilkington and the need of revealing Cenozoic and crystalline basement thickness in the new round of oil-gas exploration, we propose a joint gravity and magnetic inversion method for two-layer models by concentrating on the relationship between the change of thickness and position of the middle layer and anomaly and discuss the effects of the key parameters. Model tests and application to field data show the validity of this method.

  18. Protein fold recognition with a two-layer method based on SVM-SA, WP-NN and C4.5 (TLM-SNC).

    Science.gov (United States)

    Zangooei, Mohammad Hossein; Jalili, Saeed

    2013-01-01

    The structural knowledge of protein is crucial in understanding its biological role. An effort is made to assign a fold to a given protein in a protein fold recognition problem. A computational Two-Layer Method (TLM) based on the Support Vector Machine (SVM), the Neural Network (NN) and the Decision Tree (C4.5) has been developed in this study for the assignment of a protein sequence to a folding class in SCOP. Prediction accuracy is measured on a dataset and the accuracy of the proposed method is very promising in comparison with other classification methods.

  19. Epidemiology of Falls in Older Age

    Science.gov (United States)

    Peel, Nancye May

    2011-01-01

    Worldwide, falls among older people are a public health concern because of their frequency and adverse consequences in terms of morbidity, mortality, and quality of life, as well as their impact on health system services and costs. This epidemiological review outlines the public health burden of falls and fall-related injuries and the impact of…

  20. Falls, faints, fits and funny turns.

    NARCIS (Netherlands)

    Thijs, R.D.; Bloem, B.R.; Dijk, J.G. van

    2009-01-01

    In this practically oriented review, we will outline the clinical approach of patients with falls due to an impairment or loss of consciousness. Following a set of definitions, we describe the salient clinical features of disorders leading to such falls. Among falls caused by true loss of consciousn

  1. Epidemiology of Falls in Older Age

    Science.gov (United States)

    Peel, Nancye May

    2011-01-01

    Worldwide, falls among older people are a public health concern because of their frequency and adverse consequences in terms of morbidity, mortality, and quality of life, as well as their impact on health system services and costs. This epidemiological review outlines the public health burden of falls and fall-related injuries and the impact of…

  2. 29 CFR 1917.41 - House falls.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false House falls. 1917.41 Section 1917.41 Labor Regulations...) MARINE TERMINALS Cargo Handling Gear and Equipment § 1917.41 House falls. (a) Span beams shall be secured... working with house fall blocks. (c) Designated employees shall inspect chains, links, shackles,...

  3. The variability of meteoroid falling

    Science.gov (United States)

    Velasco Herrera, V. M.; Cordero, G.

    2016-10-01

    We analysed a historical catalogue of meteoroid falling during the last 400 years. We report here for the first time the synchronization between observed meteors and solar barycentric parameters in 19.6 and 13.2 years periodicities using a new multiple cross wavelet. The group of moderated number of meteors is distributed around the positive phase of the solar barycentric periodicity of 13.2 years. While the group of severe number of meteors are distributed on the positive phase of the solar barycentric periodicity of 19.6 years. These periodicities could be associated with Jupiter periodicities. So understanding the modulation of meteoroid falling is important for determining the falling patterns of these objects and for knowing when it is more likely to expect the entry of one of these objects into the Earth's atmosphere, because bodies falling onto the Earth can cause damage from minor impacts to mass-extinctions events. One of the most extreme events was the formation of the Chicxulub impact crater 65,000,000 years ago that caused one of the five major mass extinctions in the last 500,000,000 years. During the 20th and 21st centuries, a series of events demonstrated the importance of collisions between planets and small bodies (comets and asteroids), which included our own planet. In the case of the Earth, we can cite three examples: Tunguska, Curuça and Chelyabinsk. These events invite us to think that perhaps the occurrence of this phenomenon might be more common than we realize, but the lack of communication or people in the area where they happened prevents us from having a complete record. Modern man has not witnessed the impact of large asteroids or comets on our planet, but it has been observed on other planetary bodies. The most spectacular of these events was the collision of fragments of the comet Shoemaker-Levy 9 with Jupiter in 1994. The total energy of the 21 impacts on Jupiter's atmosphere was estimated as the equivalent of tens of millions of

  4. Film/NotFilm

    OpenAIRE

    Willems, Gertjan

    2016-01-01

    Although Samuel Beckett (1906-1989) showed a genuine interest in audio-visual media in his fascinating and innovative radio plays and television works, and in 1936 even wrote a letter to Sergei Eisenstein to be accepted to the famous Soviet film school VGIK, the 22-minute Film (1965) was his only venture into cinema. Beckett conceived the film, wrote the screenplay, supervised the production and, as one of the film’s crew members recalled and as the director Alan Schneider himself acknowledge...

  5. Efficient calculation of potential distribution in two-layer earth; Niso kozo daichikei ni okeru denki tansa no tame no koritsuteki den`i keisan shuho

    Energy Technology Data Exchange (ETDEWEB)

    Kataoka, M.; Okamoto, Y. [Chiba Institute of Technology, Chiba (Japan); Endo, M.; Noguchi, K. [Waseda University, Tokyo (Japan); Teramachi, Y.; Akabane, H. [University of Industrial Technology, Kanagawa (Japan); Agu, M. [Ibaraki University, Ibaraki (Japan)

    1997-05-27

    An efficient calculation method of potential distribution in the presence of an embedded body in multi-layer earth has been proposed by expanding the method of image with a consideration of multiple reflection between the ground surface and each underground boundary. For this method, when solving boundary integral equation with the potential of embedded body surface as only one unknown, i.e., when obtaining discretization equation, ordinary boundary element program developed for analyzing the finite closed region can be used. As an example, numerical calculation was conducted for the two-layer earth. The analysis expression of potential distribution in the case of the certain embedded body in two-layer earth has never published. Accordingly, the calculated results were compared with those by the integral equation method. As a result, it was concluded that the primary potential obtained from the present method agreed well with that obtained from the integral equation method. However, there was a disregarded difference in the secondary potential. For confirming the effectiveness, it was necessary to compare with another numerical calculation method, such as finite element method. 5 refs., 5 figs.

  6. 两层损耗土壤媒质附近HEMP环境%HEMP Environment Over Two-layer Lossy Soil

    Institute of Scientific and Technical Information of China (English)

    孙蓓云; 周辉

    2013-01-01

    To understand the HEMP environment near ground is important for HEMP effects research of ground -base electrical system.The methods to calculate the reflection wave of plane wave and electromagnetic environment over two-layer lossy media are presented.The reflection wave and electromagnetic environment of HEMP over two-layered soil are calculated.The results indicate that there are two peaks in the reflection wave and the time of the second peak is determined by the thickness of the first layer soil.The tail-wave amplitude of x-direction HEMP environment is reduced than one layer's,and the tail-wave amplitude of z-direction is increased.%介绍了分层损耗媒质反射波的计算方法,计算了大地由一定厚度的干土和湿土构成时,x方向和z方向的HEMP反射波及地面附近电磁环境.计算结果表明x方向和z方向的反射波都有双峰,第2个峰出现的时间与第1层土壤的厚度有关;地面附近x方向HEMP环境场波尾的幅度较单层的会有下降,而z方向较单层的会有增加.

  7. On the Transformation Mechanism for Formulating a Multiproduct Two-Layer Supply Chain Network Design Problem as a Network Flow Model

    Directory of Open Access Journals (Sweden)

    Mi Gan

    2014-01-01

    Full Text Available The multiproduct two-layer supply chain is very common in various industries. In this paper, we introduce a possible modeling and algorithms to solve a multiproduct two-layer supply chain network design problem. The decisions involved are the DCs location and capacity design decision and the initial distribution planning decision. First we describe the problem and give a mixed integer programming (MIP model; such problem is NP-hard and it is not easy to reduce the complexity. Inspired by it, we develop a transformation mechanism of relaxing the fixed cost and adding some virtual nodes and arcs to the original network. Thus, a network flow problem (NFP corresponding to the original problem has been formulated. Given that we could solve the NFP as a minimal cost flow problem. The solution procedures and network simplex algorithm (INS are discussed. To verify the effectiveness and efficiency of the model and algorithms, the performance measure experimental has been conducted. The experiments and result showed that comparing with MIP model solved by genetic algorithm (GA and Benders, decomposition algorithm (BD the NFP model and INS are also effective and even more efficient for both small-scale and large-scale problems.

  8. A Two-Layered Diffusion Model Traces the Dynamics of Information Processing in the Valuation-and-Choice Circuit of Decision Making

    Directory of Open Access Journals (Sweden)

    Pietro Piu

    2014-01-01

    Full Text Available A circuit of evaluation and selection of the alternatives is considered a reliable model in neurobiology. The prominent contributions of the literature to this topic are reported. In this study, valuation and choice of a decisional process during Two-Alternative Forced-Choice (TAFC task are represented as a two-layered network of computational cells, where information accrual and processing progress in nonlinear diffusion dynamics. The evolution of the response-to-stimulus map is thus modeled by two linked diffusive modules (2LDM representing the neuronal populations involved in the valuation-and-decision circuit of decision making. Diffusion models are naturally appropriate for describing accumulation of evidence over the time. This allows the computation of the response times (RTs in valuation and choice, under the hypothesis of ex-Wald distribution. A nonlinear transfer function integrates the activities of the two layers. The input-output map based on the infomax principle makes the 2LDM consistent with the reinforcement learning approach. Results from simulated likelihood time series indicate that 2LDM may account for the activity-dependent modulatory component of effective connectivity between the neuronal populations. Rhythmic fluctuations of the estimate gain functions in the delta-beta bands also support the compatibility of 2LDM with the neurobiology of DM.

  9. Thin Films

    Directory of Open Access Journals (Sweden)

    M. Benmouss

    2003-01-01

    the optical absorption are consistent with the film color changes. Finally, the optical and electrochromic properties of the films prepared by this method are compared with those of our sputtered films already studied and with other works.

  10. A fully relativistic radial fall

    CERN Document Server

    Spallicci, Alessandro D A M

    2014-01-01

    Radial fall has historically played a momentous role. It is one of the most classical problems, the solutions of which represent the level of understanding of gravitation in a given epoch. A {\\it gedankenexperiment} in a modern frame is given by a small body, like a compact star or a solar mass black hole, captured by a supermassive black hole. The mass of the small body itself and the emission of gravitational radiation cause the departure from the geodesic path due to the back-action, that is the self-force. For radial fall, as any other non-adiabatic motion, the instantaneous identity of the radiated energy and the loss of orbital energy cannot be imposed and provide the perturbed trajectory. In the first part of this letter, we present the effects due to the self-force computed on the geodesic trajectory in the background field. Compared to the latter trajectory, in the Regge-Wheeler, harmonic and all others smoothly related gauges, a far observer concludes that the self-force pushes inward (not outward) ...

  11. Studies On Falling Ball Viscometry

    CERN Document Server

    Singh, Amit Vikram; Gupta-Bhaya, Pinaki

    2012-01-01

    A new method of accurate calculation of the coefficient of viscosity of a test liquid from experimentally measured terminal velocity of a ball falling in the test liquid contained in a narrow tube is described. The calculation requires the value of a multiplicative correction factor to the apparent coefficient of viscosity calculated by substitution of terminal velocity of the falling ball in Stokes formula. This correction factor, the so-called viscosity ratio, a measure of deviation from Stokes limit, arises from non-vanishing values of the Reynolds number and the ball/tube radius ratio. The method, valid over a very wide range of Reynolds number, is based on the recognition of a relationship between two measures of wall effect, the more widely investigated velocity ratio, defined as the ratio of terminal velocity in a confined medium to that in a boundless medium and viscosity ratio. The calculation uses two recently published correlation formulae based on extensive experimental results on terminal velocit...

  12. Intrinsic Risk Factors of Falls in Elderly

    Directory of Open Access Journals (Sweden)

    Yasmin Amatullah

    2016-09-01

    Full Text Available Background: Falls are common geriatric problems. The risk factors of falls are the intrinsic and extrinsic risk factors. Studies on falls are scarcely conducted in Indonesia, especially in Bandung. Therefore, this study was conducted to identify the intrinsic risk factors of falls among elderly. Methods: A descriptive study was carried out from August to October 2013 at the Geriatric Clinic of Dr. Hasan Sadikin General Hospital Bandung. Fifty three participants were selected according to the inclusion and exclusion criteria using consecutive sampling. The determined variables in this study were classification of the risk of falls, demographic profile, history of falls, disease, and medications. After the selection, the participants were tested by Timed up-and-go test (TUGT. Moreover, an interview and analysis of medical records were carried out to discover the risk factors of falls. The collected data were analyzed and presented in the form of percentages shown in tables. Results: From 53 patients, women (35.66% were considered to have higher risk of fall than men (18.34%. The majority of patients (66% with the risk of fall were from the age group 60–74 years. The major diseases suffered by patients were hypertension, osteoarthritis and diabetes mellitus. Drugs that were widely used were antihypertensive drugs; analgesic and antipyretic drugs and antidiabetic drugs. Conclusions: There are various intrinsic risk factors of falls in elderly and each of the elderly has more than one intrinsic risk factor of falls.

  13. Piezoelectric Resonator with Two Layers

    Science.gov (United States)

    Stephanou, Philip J. (Inventor); Black, Justin P. (Inventor)

    2013-01-01

    A piezoelectric resonator device includes: a top electrode layer with a patterned structure, a top piezoelectric layer adjacent to the top layer, a middle metal layer adjacent to the top piezoelectric layer opposite the top layer, a bottom piezoelectric layer adjacent to the middle layer opposite the top piezoelectric layer, and a bottom electrode layer with a patterned structure and adjacent to the bottom piezoelectric layer opposite the middle layer. The top layer includes a first plurality of electrodes inter-digitated with a second plurality of electrodes. A first one of the electrodes in the top layer and a first one of the electrodes in the bottom layer are coupled to a first contact, and a second one of the electrodes in the top layer and a second one of the electrodes in the bottom layer are coupled to a second contact.

  14. Internship Progress Summary: Fall 2016

    Energy Technology Data Exchange (ETDEWEB)

    Wiser, Ralph S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Valencia, Matthew John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-12-13

    This fall I had the opportunity to work at Los Alamos National Laboratory for the Technology Applications engineering group. I assisted two main projects during my appointment, both related to the Lab’s mission statement: “To solve national security challenges through scientific excellence.” My first project, a thermal source transfer unit, involved skills such as mechanical design, heat transfer simulation, and design analysis. The goal was to create a container that could protect a heat source and regulate its temperature during transit. I generated several designs, performed heat transfer simulations, and chose a design for prototyping. The second project was a soil drying unit for use in post blast sample analysis. To ensure fast and accurate sample processing, agents in the field wanted a system that could process wet dirt and turn it into dry powder. We designed a system of commercially available parts, and we tested the systems to determine the best methods and processes.

  15. Falls and Fear of Falling After Stroke: A Case-Control Study.

    Science.gov (United States)

    Goh, Hui-Ting; Nadarajah, Mohanasuntharaam; Hamzah, Norhamizan Binti; Varadan, Parimalaganthi; Tan, Maw Pin

    2016-12-01

    Falls are common after stroke, with potentially serious consequences. Few investigations have included age-matched control participants to directly compare fall characteristics between older adults with and without stroke. Further, fear of falling, a significant psychological consequence of falls, has only been examined to a limited degree as a risk factor for future falls in a stroke population. To compare the fall history between older adults with and without a previous stroke and to identify the determinants of falls and fear of falling in older stroke survivors. Case-control observational study. Primary teaching hospital. Seventy-five patients with stroke (mean age ± standard deviation, 66 ± 7 years) and 50 age-matched control participants with no previous stroke were tested. Fall history, fear of falling, and physical, cognitive, and psychological function were assessed. A χ(2) test was performed to compare characteristics between groups, and logistic regression was performed to determine the risk factors for falls and fear of falling. Fall events in the past 12 months, Fall Efficacy Scale-International, Berg Balance Scale, Functional Ambulation Category, Fatigue Severity Scale, Montreal Cognitive Assessment, and Patient Healthy Questionnaire-9 were measured for all participants. Fugl-Meyer Motor Assessment was used to quantify severity of stroke motor impairments. Twenty-three patients and 13 control participants reported at least one fall in the past 12 months (P = .58). Nine participants with stroke had recurrent falls (≥2 falls) compared with none of the control participants (P control participants (P < .01). Female gender was associated with falls in the nonstroke group, whereas falls in the stroke group were not significantly associated with any measured outcomes. Fear of falling in the stroke group was associated with functional ambulation level and balance. Functional ambulation level alone explained 22% of variance in fear of falling in the

  16. Prediction of falls and/or near falls in people with mild Parkinson's disease.

    Directory of Open Access Journals (Sweden)

    Beata Lindholm

    Full Text Available To determine factors associated with future falls and/or near falls in people with mild PD.The study included 141 participants with PD. Mean (SD age and PD-duration were 68 (9.7 and 4 years (3.9, respectively. Their median (q1-q3 UPDRS III score was 13 (8-18. Those >80 years of age, requiring support in standing or unable to understand instructions were excluded. Self-administered questionnaires targeted freezing of gait, turning hesitations, walking difficulties in daily life, fatigue, fear of falling, independence in activities of daily living, dyskinesia, demographics, falls/near falls history, balance problems while dual tasking and pain. Clinical assessments addressed functional balance performance, retropulsion, comfortable gait speed, motor symptoms and cognition. All falls and near falls were subsequently registered in a diary during a six-month period. Risk factors for prospective falls and/or near falls were determined using logistic regression.Sixty-three participants (45% experienced ≥ 1 fall and/or near fall. Three factors were independent predictors of falls and/or near falls: fear of falling (OR = 1.032, p<0.001 history of near falls (OR = 3.475, p = 0.009 and retropulsion (OR = 2.813, p = 0.035. The strongest contributing factor was fear of falling, followed by a history of near falls and retropulsion.Fear of falling seems to be an important issue to address already in mild PD as well as asking about prior near falls.

  17. A Bio-Inspired Two-Layer Sensing Structure of Polypeptide and Multiple-Walled Carbon Nanotube to Sense Small Molecular Gases

    Directory of Open Access Journals (Sweden)

    Li-Chun Wang

    2015-03-01

    Full Text Available In this paper, we propose a bio-inspired, two-layer, multiple-walled carbon nanotube (MWCNT-polypeptide composite sensing device. The MWCNT serves as a responsive and conductive layer, and the nonselective polypeptide (40 mer coating the top of the MWCNT acts as a filter into which small molecular gases pass. Instead of using selective peptides to sense specific odorants, we propose using nonselective, peptide-based sensors to monitor various types of volatile organic compounds. In this study, depending on gas interaction and molecular sizes, the randomly selected polypeptide enabled the recognition of certain polar volatile chemical vapors, such as amines, and the improved discernment of low-concentration gases. The results of our investigation demonstrated that the polypeptide-coated sensors can detect ammonia at a level of several hundred ppm and barely responded to triethylamine.

  18. Convergence Improved Lax-Friedrichs Scheme Based Numerical Schemes and Their Applications in Solving the One-Layer and Two-Layer Shallow-Water Equations

    Directory of Open Access Journals (Sweden)

    Xinhua Lu

    2015-01-01

    Full Text Available The first-order Lax-Friedrichs (LF scheme is commonly used in conjunction with other schemes to achieve monotone and stable properties with lower numerical diffusion. Nevertheless, the LF scheme and the schemes devised based on it, for example, the first-order centered (FORCE and the slope-limited centered (SLIC schemes, cannot achieve a time-step-independence solution due to the excessive numerical diffusion at a small time step. In this work, two time-step-convergence improved schemes, the C-FORCE and C-SLIC schemes, are proposed to resolve this problem. The performance of the proposed schemes is validated in solving the one-layer and two-layer shallow-water equations, verifying their capabilities in attaining time-step-independence solutions and showing robustness of them in resolving discontinuities with high-resolution.

  19. Label-free logic modules and two-layer cascade based on stem-loop probes containing a G-quadruplex domain.

    Science.gov (United States)

    Guo, Yahui; Cheng, Junjie; Wang, Jine; Zhou, Xiaodong; Hu, Jiming; Pei, Renjun

    2014-09-01

    A simple, versatile, and label-free DNA computing strategy was designed by using toehold-mediated strand displacement and stem-loop probes. A full set of logic gates (YES, NOT, OR, NAND, AND, INHIBIT, NOR, XOR, XNOR) and a two-layer logic cascade were constructed. The probes contain a G-quadruplex domain, which was blocked or unfolded through inputs initiating strand displacement and the obviously distinguishable light-up fluorescent signal of G-quadruplex/NMM complex was used as the output readout. The inputs are the disease-specific nucleotide sequences with potential for clinic diagnosis. The developed versatile computing system based on our label-free and modular strategy might be adapted in multi-target diagnosis through DNA hybridization and aptamer-target interaction. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Influence of a fat layer on the near infrared spectra of human muscle: quantitative analysis based on two-layered Monte Carlo simulations and phantom experiments

    Science.gov (United States)

    Yang, Ye; Soyemi, Olusola O.; Landry, Michelle R.; Soller, Babs R.

    2005-01-01

    The influence of fat thickness on the diffuse reflectance spectra of muscle in the near infrared (NIR) region is studied by Monte Carlo simulations of a two-layer structure and with phantom experiments. A polynomial relationship was established between the fat thickness and the detected diffuse reflectance. The influence of a range of optical coefficients (absorption and reduced scattering) for fat and muscle over the known range of human physiological values was also investigated. Subject-to-subject variation in the fat optical coefficients and thickness can be ignored if the fat thickness is less than 5 mm. A method was proposed to correct the fat thickness influence. c2005 Optical Society of America.

  1. Solitons, Bäcklund transformation and Lax pair for a generalized variable-coefficient Boussinesq system in the two-layered fluid flow

    Science.gov (United States)

    Zhao, Xue-Hui; Tian, Bo; Chai, Jun; Wu, Yu-Xiao; Guo, Yong-Jiang

    2016-11-01

    Under investigation in this paper is a generalized variable-coefficient Boussinesq system, which describes the propagation of the shallow water waves in the two-layered fluid flow. Bilinear forms, Bäcklund transformation and Lax pair are derived by virtue of the Bell polynomials. Hirota method is applied to construct the one- and two-soliton solutions. Propagation and interaction of the solitons are illustrated graphically: kink- and bell-shape solitons are obtained; shapes of the solitons are affected by the variable coefficients α1, α3 and α4 during the propagation, kink- and anti-bell-shape solitons are obtained when α3 > 0, anti-kink- and bell-shape solitons are obtained when α3 < 0; Head-on interaction between the two bidirectional solitons, overtaking interaction between the two unidirectional solitons are presented; interactions between the two solitons are elastic.

  2. An outpatient multifactorial falls prevention intervention does not reduce falls in high-risk elderly Danes

    DEFF Research Database (Denmark)

    Vind, Ane B; Andersen, Hanne E; Pedersen, Kirsten D

    2009-01-01

    OBJECTIVES: To evaluate the effect of multifactorial fall prevention in community-dwelling people aged 65 and older in Denmark. DESIGN: Randomized, controlled clinical trial. SETTING: Geriatric outpatient clinic at Glostrup University Hospital. PARTICIPANTS: Three hundred ninety-two elderly people......, mean age 74, 73.7%women, who had visited the emergency department or had been hospitalized due to a fall. INTERVENTION: Identification of general medical, cardiovascular, and physical risk factors for falls and individual intervention in the intervention group. Participants in the control group...... received usual care. MEASUREMENTS: Falls were registered prospectively in falls diaries, with monthly telephone calls for collection of data. Outcomes were fall rates and proportion of participants with falls, frequent falls, and injurious falls in 12 months. RESULTS: Groups were comparable at baseline...

  3. Two-layer hierarchical control solutions for traffic signal%面向交通信号的两层递阶控制解决方案

    Institute of Scientific and Technical Information of China (English)

    戈军; 周莲英

    2015-01-01

    针对现有交通信号控制系统的诸多不足,提出了一种用于交通信号控制的两层递阶多Agent系统解决方案。通过将交通网络进行区域划分,利用底层Agent控制各交叉口,顶层Agent控制区域,从而实现两层递阶控制。底层Agent采用经典Q学习同步学习最优策略,顶层Agent利用Tile Coding非凡的连续空间处理能力,实现Q学习的动作值函数逼近方法。仿真实验结果表明,该分层递阶控制不但提高了交通信号控制系统效率,而且也为大规模应用提供了很好的可伸缩解决方案。%In view of the existing deficiencies of traffic signal control system, this paper proposes two-layer hierarchical multi-Agent system solution for traffic signal control. Through regional division of the traffic network, it uses the bottom level Agent to control the intersection, the top level Agent to control areas, so as to achieve the two-layer hierarchical con-trol. The bottom level Agent uses the classical Q-learning to synchronize the optimal strategy, the top level Agent utilizes the special continuous space processing ability of Tile Coding to achieve Q learning of action value function approxima-tion method. The simulation test results show that, the hierarchical control not only improves the efficiency of traffic signal control system, but also provides a good scalable solution for large-scale applications.

  4. Falls in the Elderly: A Practical Approach

    OpenAIRE

    Handfield-Jones, Richard

    1989-01-01

    Falls in the elderly constitute a major problem confronting physicians. Their cost to individual patients and to society in terms of incidence, morbidity, and mortality is enormous. This paper attempts to outline some of the common etiological factors related to falls and a practical approach to the diagnosis and management. Causes of falls are clssified as extrinsic and intrinsic factors. The latter include disorders of many organ systems, especially those resulting from neurological and car...

  5. Predictors of future falls in Parkinson disease.

    Science.gov (United States)

    Kerr, G K; Worringham, C J; Cole, M H; Lacherez, P F; Wood, J M; Silburn, P A

    2010-07-13

    Falls are a major health and injury problem for people with Parkinson disease (PD). Despite the severe consequences of falls, a major unresolved issue is the identification of factors that predict the risk of falls in individual patients with PD. The primary aim of this study was to prospectively determine an optimal combination of functional and disease-specific tests to predict falls in individuals with PD. A total of 101 people with early-stage PD undertook a battery of neurologic and functional tests in their optimally medicated state. The tests included Tinetti, Berg, Timed Up and Go, Functional Reach, and the Physiological Profile Assessment of Falls Risk; the latter assessment includes physiologic tests of visual function, proprioception, strength, cutaneous sensitivity, reaction time, and postural sway. Falls were recorded prospectively over 6 months. Forty-eight percent of participants reported a fall and 24% more than 1 fall. In the multivariate model, a combination of the Unified Parkinson's Disease Rating Scale (UPDRS) total score, total freezing of gait score, occurrence of symptomatic postural orthostasis, Tinetti total score, and extent of postural sway in the anterior-posterior direction produced the best sensitivity (78%) and specificity (84%) for predicting falls. From the UPDRS items, only the rapid alternating task category was an independent predictor of falls. Reduced peripheral sensation and knee extension strength in fallers contributed to increased postural instability. Falls are a significant problem in optimally medicated early-stage PD. A combination of both disease-specific and balance- and mobility-related measures can accurately predict falls in individuals with PD.

  6. Visual impairment and falls: a register study.

    Science.gov (United States)

    Källstrand-Ericson, Jeanette; Hildingh, Cathrine

    2009-02-01

    The aim of this register study was to investigate falls and fall injuries of inpatients 65 years and over to determine whether a causal factor of visual impairment was documented. All Organisation for Economic Cooperation and Development (OECD) countries have an increasing older population with falls and fall injuries becoming a major problem. A visual impairment can be an independent risk factor for falls but can also occur in combination with other intrinsic and extrinsic risk factors. A retrospective non-randomised register study. In 2004, all documented falls of inpatients aged 65 years and over were examined. Medical records and eye clinic records were scrutinised to identify whether any visual impairment have been documented. The majority of falls occurred between the hours of 24:00-06:00 and the inpatients most often affected were those with a visual impairment. The falls occurred in connection with movement when the inpatient was unaccompanied. Documentation in records at the medical clinic was defective and subjectively perceived visual impairment was not documented at all. Both subjective and objective visual impairment occurred in all eye clinic records. Visual impairment along with the ageing process are features affecting falls and the hospital environment needs to be adapted by improving the use of strong, contrasting colours and providing good lighting for older inpatients with visual impairment during the night time period. Hospital safety for older people with visual impairment is a concern if falls are to be reduced. Healthcare professionals need to undertake individual risk assessments to establish the degree of visual impairment of the older person so that appropriate interventions can be implemented to reduce the incidence of falls and fall injuries.

  7. An outpatient multifactorial falls prevention intervention does not reduce falls in high-risk elderly Danes

    DEFF Research Database (Denmark)

    Vind, Ane B; Andersen, Hanne E; Pedersen, Kirsten D

    2009-01-01

    OBJECTIVES: To evaluate the effect of multifactorial fall prevention in community-dwelling people aged 65 and older in Denmark. DESIGN: Randomized, controlled clinical trial. SETTING: Geriatric outpatient clinic at Glostrup University Hospital. PARTICIPANTS: Three hundred ninety-two elderly people......% CI 0.81-1.79), frequent falls (OR=0.97, 95% CI=0.60-1.56), or injurious falls (OR=0.97, 95% CI=0.57-1.62). CONCLUSION: A program of multifactorial fall prevention aimed at elderly Danish people experiencing at least one injurious fall was not effective in preventing further falls....

  8. Automatic Fall Detection using Smartphone Acceleration Sensor

    Directory of Open Access Journals (Sweden)

    Tran Tri Dang

    2016-12-01

    Full Text Available In this paper, we describe our work on developing an automatic fall detection technique using smart phone. Fall is detected based on analyzing acceleration patterns generated during various activities. An additional long lie detection algorithm is used to improve fall detection rate while keeping false positive rate at an acceptable value. An application prototype is implemented on Android operating system and is used to evaluate the proposed technique performance. Experiment results show the potential of using this app for fall detection. However, more realistic experiment setting is needed to make this technique suitable for use in real life situations.

  9. Effectiveness of team training on fall prevention.

    Science.gov (United States)

    Spiva, LeeAnna; Robertson, Bethany; Delk, Marcia L; Patrick, Sara; Kimrey, Margaret Michelle; Green, Beverly; Gallagher, Erin

    2014-01-01

    A longitudinal, repeated-measures design with intervention and comparison groups was used to evaluate the effect of a training curriculum based on TeamSTEPPS with video vignettes focusing on fall prevention. Questionnaires, behavioral observations, and fall data were collected over 9 months from both groups located at separate hospitals. The intervention group questionnaire scores improved on all measures except teamwork perception, while observations revealed an improvement in communication compared with the control group. Furthermore, a 60% fall reduction rate was reported in the intervention group. Team training may be a promising intervention to reduce falls.

  10. Radar fall detection using principal component analysis

    Science.gov (United States)

    Jokanovic, Branka; Amin, Moeness; Ahmad, Fauzia; Boashash, Boualem

    2016-05-01

    Falls are a major cause of fatal and nonfatal injuries in people aged 65 years and older. Radar has the potential to become one of the leading technologies for fall detection, thereby enabling the elderly to live independently. Existing techniques for fall detection using radar are based on manual feature extraction and require significant parameter tuning in order to provide successful detections. In this paper, we employ principal component analysis for fall detection, wherein eigen images of observed motions are employed for classification. Using real data, we demonstrate that the PCA based technique provides performance improvement over the conventional feature extraction methods.

  11. Nuclear winter or nuclear fall?

    Science.gov (United States)

    Berger, André

    Climate is universal. If a major modern nuclear war (i.e., with a large number of small-yield weapons) were to happen, it is not even necessary to have a specific part of the world directly involved for there to be cause to worry about the consequences for its inhabitants and their future. Indeed, smoke from fires ignited by the nuclear explosions would be transported by winds all over the world, causing dark and cold. According to the first study, by Turco et al. [1983], air surface temperature over continental areas of the northern mid-latitudes (assumed to be the nuclear war theatre) would fall to winter levels even in summer (hence the term “nuclear winter”) and induce drastic climatic conditions for several months at least. The devastating effects of a nuclear war would thus last much longer than was assumed initially. Discussing to what extent these estimations of long-term impacts on climate are reliable is the purpose of this article.

  12. Klamath Falls geothermal field, Oregon

    Energy Technology Data Exchange (ETDEWEB)

    Lienau, P.J.; Culver, G.; Lund, J.W.

    1989-09-01

    Klamath Falls, Oregon, is located in a Known Geothermal Resource Area which has been used by residents, principally to obtain geothermal fluids for space heating, at least since the turn of the century. Over 500 shallow-depth wells ranging from 90 to 2,000 ft (27 to 610 m) in depth are used to heat (35 MWt) over 600 structures. This utilization includes the heating of homes, apartments, schools, commercial buildings, hospital, county jail, YMCA, and swimming pools by individual wells and three district heating systems. Geothermal well temperatures range from 100 to 230{degree}F (38 to 110{degree}C) and the most common practice is to use downhole heat exchangers with city water as the circulating fluid. Larger facilities and district heating systems use lineshaft vertical turbine pumps and plate heat exchangers. Well water chemistry indicates approximately 800 ppM dissolved solids, with sodium sulfate having the highest concentration. Some scaling and corrosion does occur on the downhole heat exchangers (black iron pipe) and on heating systems where the geo-fluid is used directly. 73 refs., 49 figs., 6 tabs.

  13. Experiments on melt droplets falling into a water pool

    Energy Technology Data Exchange (ETDEWEB)

    Okkonen, T.; Sehgal, B.R. [Royal Inst. of Tech., Stockholm (Sweden). Div. of Nuclear Power Safety

    1998-01-01

    This paper presents experimental data and analysis related to melt droplets falling into a water pool. A binary CaO-B{sub 2}O{sub 3} melt mixture is used to study the influence of melt superheat and water subcooling on droplet deformation and fragmentation. For the conditions studied (We {<=} 1000), the surface tension of the melt droplet and the film boiling stability greatly affect the fragmentation behaviour. If the melt temperature is between the liquidus and solidus point (mushy zone) or if the film boiling is stable due to a relatively low subcooling, the droplet deformation and fragmentation are mitigated. This behaviour can be related to the effective Weber number (We) of the melt droplet upon entry into the water pool. Similar phenomena can be expected also for interactions of corium (UO{sub 2}-ZrO{sub 2}) and water, which are characterized by a potentially fast transformation of melt into the mushy zone and by particularly stable film boiling. (author)

  14. Approach to Fall in Elderly Population

    Directory of Open Access Journals (Sweden)

    Mehmet Ilkin Naharci

    2009-10-01

    Full Text Available Falls are one of the geriatric syndromes which occur commonly and significantly increase morbidity and mortality rates in elderly. The incidence of falls increases with age. Falls usually occur when impairments in cognitive, behavioral, and executive function begin. The incidence of fall is between 30 and 40 percent of community-dwelling people and approximately 50 percent of individuals in the long-term care setting over the age of 65 years. Fracture (hip, arm, wrist, pelvis, head trauma or major lacerations, as defined serious wounding, occur 10-25% of elderly cases. Fall is overlooked in clinical examination due to various reasons; the patient never mentions the event to a doctor; there is no injury at the time of the fall; the doctor fails to ask the patient about a history of falls; or either doctor or patient erroneously believes that falls are an inevitable part of the aging process. Elderly give not usually any self-information about fall, for this reason, all older patients should be asked at least once per year about falls and should be assessed in terms of balance and gait disorders. There are many distinct causes for falls in old people. Falls in older individuals occur when a threat to the normal homeostatic mechanisms that maintain postural stability is superimposed on underlying age-related declines in balance, ambulation, and cardiovascular function. This factor may be an acute illness (eg, fever, water loss, arrhythmia, a new medication, an environmental stress (eg, unfamiliar surrounding, or an unsafe walking surface. The elderly person can not cope with happened additional stress. To prevent and decrease the frequency of falls, effective approaches are medical interventions, environmental modifications, education-exercise programs, and assisted device. Detection and amelioration of risk factors can significantly reduce the rate of future falls. The assessment of fall, causing mobility restriction, use of nursing home, and

  15. Risk of falling, fear of falling and functionality in community-dwelling older adults

    OpenAIRE

    Fernandes, Beatriz; Tomás, Mª Teresa; Quirino, Diogo

    2016-01-01

    Ageing among Portuguese population is leading to an increase in the proportion of elderly people. Age-related changes are responsible for high levels of disability, balance problems and high risk of falls, Physiotherapy can identify elderly in risk of falling and provide strategies to prevent falls in this population contributing to maintain functionality. The purpose of this study was to characterise the risk of falling in a sample of community-dwelling older adults and investigate the assoc...

  16. Morphologic studies of high fall injuries

    Directory of Open Access Journals (Sweden)

    XIA Peng

    2012-12-01

    Full Text Available 【Abstract】 Objective: By studying the mode and morphologic character of high fall injuries on the scene, and exploring the injury situation of different heights, different fall ways and postures, to provide a reference for the foren-sic identification of high fall injury. Methods: All the high fall cases were statistically analysed according to their gender, age, ground-touching posture, fall height, site and type of the injury. Results: Among 134 high fall cases, 98 were male and 36 were female with the age ranging from 2-71 years (37.6 ±16.9 on average, in which, 10-60 years old group con-sisted of 110 cases (82%. Most cases fell from windows or roofs (73% and the touching objects were cement ground or shaft bottom of elevators. Among these cases, head injury was generally serious, followed by chest and abdominal injuries. The morphologic changes depend upon the height, nature, as well as the posture at the point while the body touches the ground. Conclusion: Morphologic study of high fall injury assists medicolegal physicians to make correct identifica-tions of the cause and nature of high fall injuries. Key words: Wounds and injuries; Forensic medicine; Anatomy and histology

  17. Osteosarcopenic obesity and fall prevention strategies.

    Science.gov (United States)

    Hita-Contreras, Fidel; Martínez-Amat, Antonio; Cruz-Díaz, David; Pérez-López, Faustino R

    2015-02-01

    Sarcopenia, obesity, and osteoporosis are three interrelated entities which may share common pathophysiological factors. In the last decades, overall survival has drastically increased. Postmenopausal women, due to their estrogen depletion, are at higher risk of developing any of these three conditions or the three, which is termed osteosarcopenic obesity. One of the most common health problems among these patients is the elevated risk of falls and fractures. Falls and fall-related injuries are one of the major causes of mortality and morbidity in older adults, and have a significant impact on social, economical and health-related costs. Several extrinsic and intrinsic risk factors have been described that play a role in the etiology of falls. A therapeutic approach to osteosarcopenic obesity aimed at the prevention of falls must include several factors, and act on those risk elements which can be effectively modified. An adequate weight-loss diet and a good nutritional intake, with an appropriate amount of vitamin D and the right protein/carbohydrates ratio, may contribute to the prevention of falls. The recommendation of physical exercise, both traditional (resistance or aerobic training) and more recent varieties (Tai Chi, Pilates, body vibration), can improve balance and positively contribute to fall prevention, whether by itself or in combination with other therapeutic strategies. Finally, a pharmacological approach, especially one focused on hormone therapy, has shown to have a positive effect on postmenopausal women's balance, leading to a decreased risk of falls. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  18. The Latino Experience in Central Falls

    Science.gov (United States)

    Holland, William R.

    2011-01-01

    Central Falls is, by far, the poorest community in Rhode Island. More than 40 percent of the children under 18 live in poverty, and 40 percent of that group live in severe poverty. At Central Falls High School, low-income Latino students have fallen behind their white counterparts, with shockingly low graduation, poor literacy, and low…

  19. Studies on fall armyworm migration and monitoring

    Science.gov (United States)

    Spodoptera frugiperda (J.E. Smith; Lepidoptera: Noctuidae) or fall armyworm is an important agricultural pest of a number of crops in thewestern hemisphere. Two morphologically identical host strains of fall armyworm exist, the rice-strain and corn-strain, with the latter inflicting substantial eco...

  20. Nurses' Job Satisfaction and Patient Falls

    Directory of Open Access Journals (Sweden)

    Cecilia D. Alvarez, DNP, RN

    2007-09-01

    Results and Conclusion: No significant relationship was found between overall nurses' job satisfaction and patient fall rate. MD–RN interactions (r = .65 and decision-making (r = .57 were the job satisfaction subscales that showed a significant positive correlation with patient fall rate (p < .05. Recommendations for future research are provided.

  1. Morphologic studies of high fall injuries

    Institute of Scientific and Technical Information of China (English)

    XIA Peng; CHANG Hong-fa; YU Yong-min; DAI Guo-xin; LI Hong-wei; JIANG Qiang-guo; YIN Zhi-yong

    2012-01-01

    Objective:By studying the mode and morphologic character of high fall injuries on the scene,and exploring the injury situation of different heights,different fall ways and postures,to provide a reference for the forensic identification of high fall injury.Methods:All the high fall cases were statistically analysed according to their gender,age,ground-touching posture,fall height,site and type of the injury.Results:Among 134 high fall cases,98 were male and 36 were female with the age ranging from 2-71 years (37.6±16.9 on average),in which,10-60 years old group consisted of 110 cases (82%).Most cases fell from windows or roofs (73%) and the touching objects were cement ground or shaft bottom of elevators.Among these cases,head injury was generally serious,followed by chest and abdominal injuries.The morphologic changes depend upon the height,nature,as well as the posture at the point while the body touches the ground.Conclusion:Morphologic study of high fall injury assists medicolegal physicians to make correct identifications of the cause and nature of high fall injuries.

  2. Falls and stumbles in myotonic dystrophy.

    Science.gov (United States)

    Wiles, C M; Busse, M E; Sampson, C M; Rogers, M T; Fenton-May, J; van Deursen, R

    2006-03-01

    To investigate falls and risk factors in patients with myotonic dystrophy type 1 (DM1) compared with healthy volunteers. 13 sequential patients with DM1 from different kindreds were compared with 12 healthy volunteers. All subjects were evaluated using the Rivermead Mobility Index, Performance Oriented Mobility Assessment, and modified Activities Specific Balance Confidence scale. Measures of lower limb muscle strength, gait speed, and 7-day ambulatory activity monitoring were recorded. Subjects returned a weekly card detailing stumbles and falls. 11 of 13 patients (mean age 46.5 years, seven female) had 127 stumbles and 34 falls over the 13 weeks, compared with 10 of 12 healthy subjects (34.4 years, seven female) who had 26 stumbles and three falls. Patients were less active than healthy subjects but had more falls and stumbles per 5000 right steps taken (mean (SD) events, 0.21 (0.29) v 0.02 (0.02), p = 0.007). Patients who fell (n = 6) had on average a lower Rivermead Mobility score, slower self selected gait speed, and higher depression scores than those who did not. DM1 patients stumble or fall about 10 times more often than healthy volunteers. Routine inquiry about falls and stumbles is justified. A study of multidisciplinary intervention to reduce the risk of falls seems warranted.

  3. Tips for Handling Gourds this Fall Season

    OpenAIRE

    Bratsch, Tony

    2009-01-01

    Each year, more direct market and wholesale growers are adding gourds to their fall sales mix, along with pumpkins, ornamental corn and fall mums. Proper harvest timing, handling and curing are important to ensure maximum longevity of gourds once the consumer brings them home.

  4. How Fast Does a Building Fall?

    Science.gov (United States)

    Denny, Mark

    2010-01-01

    In this paper, the time required for a tower block to collapse is calculated. The tower collapses progressively, with one floor falling onto the floor below, causing it to fall. The rate of collapse is found to be not much slower than freefall. The calculation is an engaging and relevant application of Newton's laws, suitable for undergraduate…

  5. Playful home training for falls prevention

    DEFF Research Database (Denmark)

    Jessen, Jari Due; Lund, Henrik Hautop

    2015-01-01

    Falling is a big issue among elderly, and prevention of falling is of big importance both for the individual and for society at large. In this paper we present a pilot study with fun exergaming equipment in private homes. The initial findings in the small pilot study suggests that this kind...

  6. Novel transparent and flexible nanocomposite film prepared from chrysotile nanofibres

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Kun, E-mail: kliu@csu.edu.cn [School of Minerals Processing and Bioengineering, Central South University, Changsha 410083 (China); Zhu, Binnan; Feng, Qiming [School of Minerals Processing and Bioengineering, Central South University, Changsha 410083 (China); Duan, Tao [Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology and Research Center of Laser Fusion, CAEP, Mianyang 621010 (China)

    2013-10-01

    In the present study, chrysotile nanofibres, obtained from physicochemical dispersion of natural chrysotile, were used to prepare nanofibre sheets by vacuum filtration. As-prepared sheets were then impregnated by UV-curable resin and cured by ultraviolet light to fabricate the flexible and transparent nanocomposite films. Observed from SEM, the transparent films showed a smooth surface and a typical sandwich structure in cross section, viz. nanofibre sheet filled with resin was sandwiched by two layers of resin. XRD patterns indicated the amorphous nature of cured resin and characteristic crystallographic structure of chrysotile in nanocomposite films. Though the nanofibre sheets were white in colour, and nanofibre contents in nanocomposites were as much as 43.4 wt%, the nanocomposite films displayed an excellent optical transparency with about 85% light transmittance in the visible light range. Tensile tests showed that the addition of nanofibres resulted in a great improvement in mechanical strength of the nanocomposite films; with the increase of nanofibre contents, the modulus and tensile strength of nanocomposite films increased gradually. - Graphical abstract: Photos show the experimental phenomenon. The white nanofibre sheets can be written or printed like paper, and it's very interested that the handwriting is clearly visible from the front and back of the transparent films prepared from nanofibre sheets by vacuum impregnation and UV curing. This phenomenon can be attributed to the increase of transparency of film, which results from the replacement of air interstices in nanofibre sheet by resin with higher refractive index. Visible light can pass easily through the transparent film without obvious loss, but can be apparently adsorbed and scattered by ink particles that adhered to nanofibres and embedded in resin. - Highlights: • A flexible and transparent film is prepared from chrysotile nanofibres. • The nanofibre sheet is sandwiched by two

  7. [Fear of falling in a fall clinic for geriatric patients: a pilot study

    NARCIS (Netherlands)

    Dautzenberg, P.L.; Buurman, B.H.; Loonen, A.J.; Wouters, C.J.; Olde Rikkert, M.G.M.

    2005-01-01

    OBJECTIVE: In this pilot study we want to determine how often fear of falling occurs in geriatric patients visiting a fall clinic and to study the characteristics of fear of falling and its consequences. DESIGN: Retrospective study of patient's records. METHOD: A random sample of 100 medical records

  8. The effects of time pressure and experience on the performance of fall techniques during a fall.

    NARCIS (Netherlands)

    Swigchem, R. van; Groen, B.E.; Weerdesteijn, V.G.M.; Duysens, J.E.J.

    2009-01-01

    Although the practice of fall techniques has been introduced in fall prevention programs, it is not clear whether people can apply acquired techniques during a real-life fall. It would be helpful to know the time it takes to initiate and to successfully execute such techniques, as well as the effect

  9. Prospective study of falls and risk factors for falls in adults with advanced cancer.

    LENUS (Irish Health Repository)

    Stone, Carol A

    2012-06-10

    Retrospective studies of inpatients with cancer suggest that a cancer diagnosis confers a high risk of falls. In adults with advanced cancer, we aimed to prospectively document the incidence of falls, identify the risk factors, and determine if falls in this population occur predominantly in older patients.

  10. Risk Factors for Falls and Fall-related Fractures in the Elderly

    NARCIS (Netherlands)

    G. Ziere (Gijsbertus)

    2007-01-01

    textabstractFalls are among the most common and serious problems facing older persons and are associated with considerable morbidity and mortality. They often lead to reduced functioning and nursing home admissions. The incidence of falls as well as the severity of fall-related complications rises s

  11. Fall Meeting by the numbers

    Science.gov (United States)

    Asher, Pranoti

    2012-02-01

    - Visits to the Fall Meeting Web site: 650,000 - Total participants at the meeting: 20,890 - Abstracts submitted to the meeting: 20,087 - Donors who attended and took advantage of donor lounges: 1835 - Total attendance at Simon Winchester's Presidential Forum Lecture: 1200 - Total attendance at the Honors Banquet: 905 - Books sold at the AGU Marketplace: 671 - Individuals registered for the Fun Run: 487 - Students who participated in the Student Breakfast: 450 - Individuals who crossed the finish line at the Fun Run: 384 - Total attendees at Exploration Station: 307 - Total booths sold in the Exhibit Hall: 304 - registered for the meeting: 288 - Membership transactions completed for renewing and registering members at AGU Marketplace: 156 - Meeting attendees who were past Congressional Visits Day participants: 82 - Editors, associate editors, and their student guests who visited the Editors Resource Center: 63 - Copies of Navigating Graduate School and Beyond: A Career Guide for Graduate Students and a Must Read for Every Advisor sold during and after the talk and book signing by author Sundar A. Christopher: 50 - Kegs of beer consumed during the Ice Breaker on Sunday, 4 December: 48 - Hours of video footage shot at the meeting by the AGU videographer: 40 - Potential geopress authors and editors who attended the daily "Come Publish With geopress" sessions in the AGU Marketplace: 31 - Press conferences held at the meeting: 25 - Average age of minors attending Exploration Station: 8.7 - Educational seminars sponsored by AGU Publications: 2 (one on how to write a good scientific paper and the other on the rewards of reviewing) - Watching three preschoolers in space suits waiting to meet astronaut Andrew Feustel after the Public Lecture: Priceless (with apologies to Mastercard®)

  12. Investigation of the falling water flow with evaporation for the passive containment cooling system and its scaling-down criteria

    Science.gov (United States)

    Li, Cheng; Li, Junming; Li, Le

    2017-09-01

    Falling water evaporation cooling could efficiently suppress the containment operation pressure during the nuclear accident, by continually removing the core decay heat to the atmospheric environment. In order to identify the process of large-scale falling water evaporation cooling, the water flow characteristics of falling film, film rupture and falling rivulet were deduced, on the basis of previous correlation studies. The influences of the contact angle, water temperature and water flow rates on water converge along the flow direction were then numerically obtained and results were compared with the data for AP1000 and CAP1400 nuclear power plants. By comparisons, it is concluded that the water coverage fraction of falling water could be enhanced by either reducing the surface contact angle or increasing the water temperature. The falling water flow with evaporation for AP1000 containment was then calculated and the feature of its water coverage fraction was analyzed. Finally, based on the phenomena identification of falling water flow for AP1000 containment evaporation cooling, the scaling-down is performed and the dimensionless criteria were obtained.

  13. Fall Detection Using Smartphone Audio Features.

    Science.gov (United States)

    Cheffena, Michael

    2016-07-01

    An automated fall detection system based on smartphone audio features is developed. The spectrogram, mel frequency cepstral coefficents (MFCCs), linear predictive coding (LPC), and matching pursuit (MP) features of different fall and no-fall sound events are extracted from experimental data. Based on the extracted audio features, four different machine learning classifiers: k-nearest neighbor classifier (k-NN), support vector machine (SVM), least squares method (LSM), and artificial neural network (ANN) are investigated for distinguishing between fall and no-fall events. For each audio feature, the performance of each classifier in terms of sensitivity, specificity, accuracy, and computational complexity is evaluated. The best performance is achieved using spectrogram features with ANN classifier with sensitivity, specificity, and accuracy all above 98%. The classifier also has acceptable computational requirement for training and testing. The system is applicable in home environments where the phone is placed in the vicinity of the user.

  14. Falls in the Elderly: A Practical Approach

    Science.gov (United States)

    Handfield-Jones, Richard

    1989-01-01

    Falls in the elderly constitute a major problem confronting physicians. Their cost to individual patients and to society in terms of incidence, morbidity, and mortality is enormous. This paper attempts to outline some of the common etiological factors related to falls and a practical approach to the diagnosis and management. Causes of falls are clssified as extrinsic and intrinsic factors. The latter include disorders of many organ systems, especially those resulting from neurological and cardiovascular diseases. The role of drugs and alcohol is stressed. Determining the cause of falls requires a thorough history and physical examination. In order to manage successfully an elderly person with multiple falls, a co-ordinated effort by a multi-disciplinary team is often essential. PMID:21249001

  15. Risk of falling in pediatric nursing

    Directory of Open Access Journals (Sweden)

    Jana Chromá

    2016-12-01

    Full Text Available Aim: The aim of this article is to describe, analyze and compare the assessment tools used to evaluate risk of falling in pediatric nursing. Design: Review - literature review. Methods: Electronic licensed and freely accessible databases (Bibliographia Medica Čechoslovaca, MEDLINE, Web of Science, PubMed a Scopus were used to obtain data. Instruments for measuring risk of falling in languages other than Czech, Slovak or English, and scales unsuitable for measuring risk of falling in pediatric nursing were excluded from the analysis. Results: From analysis of the collected information, the most suitable tool for assessment of risk of falling in pediatric nursing seems to be the Humpty Dumpty measuring scale. Conclusion: At present there are many assessment tools that can be used to evaluate the risk of falling in pediatric nursing, but most are available in English. Czech pediatric nursing continues to lack measuring tools with verified psychometric properties.

  16. Desert shrub responses to experimental modification of precipitation seasonality and soil depth: relationship to the two-layer model and ecohydrological niche

    Science.gov (United States)

    Germino, Matthew J.; Reinhardt, Keith

    2013-01-01

    1. Ecohydrological niches are important for understanding plant community responses to climate shifts, particularly in dry lands. According to the two-layer hypothesis, selective use of deep-soil water increases growth or persistence of woody species during warm and dry summer periods and thereby contributes to their coexistence with shallow-rooted herbs in dry ecosystems. The resource-pool hypothesis further suggests that shallow-soil water benefits growth of all plants while deep-soil water primarily enhances physiological maintenance and survival of woody species. Few studies have directly tested these by manipulating deep-soil water availability and observing the long-term outcomes. 2. We predicted that factors promoting infiltration and storage of water in deep soils, specifically greater winter precipitation and soil depth, would enhance Artemisia tridentata (big sagebrush) in cold, winter-wet/summer-dry desert. Sagebrush responses to 20 years of winter irrigation were compared to summer- or no irrigation, on plots having relatively deep or shallow soils (2 m vs. 1 m depths). 3. Winter irrigation increased sagebrush cover, and crown and canopy volumes, but not density (individuals/plot) compared to summer or no irrigation, on deep-soil plots. On shallow-soil plots, winter irrigation surprisingly decreased shrub cover and size, and summer irrigation had no effect. Furthermore, multiple regression suggested that the variations in growth were related (i) firstly to water in shallow soils (0-0.2 m) and secondly to deeper soils (> 1 m deep) and (ii) more by springtime than by midsummer soil water. Water-use efficiency increased considerably on shallow soils without irrigation and was lowest with winter irrigation. 4. Synthesis. Sagebrush was more responsive to the seasonal timing of precipitation than to total annual precipitation. Factors that enhanced deep-water storage (deeper soils plus more winter precipitation) led to increases in Artemisia tridentata that

  17. Estimation of available water capacity components of two-layered soils using crop model inversion: Effect of crop type and water regime

    Science.gov (United States)

    Sreelash, K.; Buis, Samuel; Sekhar, M.; Ruiz, Laurent; Kumar Tomer, Sat; Guérif, Martine

    2017-03-01

    Characterization of the soil water reservoir is critical for understanding the interactions between crops and their environment and the impacts of land use and environmental changes on the hydrology of agricultural catchments especially in tropical context. Recent studies have shown that inversion of crop models is a powerful tool for retrieving information on root zone properties. Increasing availability of remotely sensed soil and vegetation observations makes it well suited for large scale applications. The potential of this methodology has however never been properly evaluated on extensive experimental datasets and previous studies suggested that the quality of estimation of soil hydraulic properties may vary depending on agro-environmental situations. The objective of this study was to evaluate this approach on an extensive field experiment. The dataset covered four crops (sunflower, sorghum, turmeric, maize) grown on different soils and several years in South India. The components of AWC (available water capacity) namely soil water content at field capacity and wilting point, and soil depth of two-layered soils were estimated by inversion of the crop model STICS with the GLUE (generalized likelihood uncertainty estimation) approach using observations of surface soil moisture (SSM; typically from 0 to 10 cm deep) and leaf area index (LAI), which are attainable from radar remote sensing in tropical regions with frequent cloudy conditions. The results showed that the quality of parameter estimation largely depends on the hydric regime and its interaction with crop type. A mean relative absolute error of 5% for field capacity of surface layer, 10% for field capacity of root zone, 15% for wilting point of surface layer and root zone, and 20% for soil depth can be obtained in favorable conditions. A few observations of SSM (during wet and dry soil moisture periods) and LAI (within water stress periods) were sufficient to significantly improve the estimation of AWC

  18. Falls and falls efficacy: the role of sustained attention in older adults

    LENUS (Irish Health Repository)

    O'Halloran, Aisling M

    2011-12-19

    Abstract Background Previous evidence indicates that older people allocate more of their attentional resources toward their gait and that the attention-related changes that occur during aging increase the risk of falls. The aim of this study was to investigate whether performance and variability in sustained attention is associated with falls and falls efficacy in older adults. Methods 458 community-dwelling adults aged ≥ 60 years underwent a comprehensive geriatric assessment. Mean and variability of reaction time (RT), commission errors and omission errors were recorded during a fixed version of the Sustained Attention to Response Task (SART). RT variability was decomposed using the Fast Fourier Transform (FFT) procedure, to help characterise variability associated with the arousal and vigilance aspects of sustained attention. The number of self-reported falls in the previous twelve months, and falls efficacy (Modified Falls Efficacy Scale) were also recorded. Results Significant increases in the mean and variability of reaction time on the SART were significantly associated with both falls (p < 0.01) and reduced falls efficacy (p < 0.05) in older adults. An increase in omission errors was also associated with falls (p < 0.01) and reduced falls efficacy (p < 0.05). Upon controlling for age and gender affects, logistic regression modelling revealed that increasing variability associated with the vigilance (top-down) aspect of sustained attention was a retrospective predictor of falling (p < 0.01, OR = 1.14, 95% CI: 1.03 - 1.26) in the previous year and was weakly correlated with reduced falls efficacy in non-fallers (p = 0.07). Conclusions Greater variability in sustained attention is strongly correlated with retrospective falls and to a lesser degree with reduced falls efficacy. This cognitive measure may provide a novel and valuable biomarker for falls in older adults, potentially allowing for early detection and the implementation of preventative intervention

  19. Reducing falls in a care home

    Science.gov (United States)

    Cooper, Rosie

    2017-01-01

    Care home residents are 3 times more likely to fall than their community dwelling peers and 10 times more likely to sustain a significant injury as a result. 2 A project commenced at a care home in Aberdeen with the aim of reducing the number of falls by 20% by 30st April 2016 using the model for improvement. Qualitative data was gathered to establish staff belief about falls and their level of knowledge& understanding about falls risks and how to manage these. This informed the training which was delivered and iterative testing commenced with the introduction of the Lanarkshire Falls Risk/Intervention tool – where the multifactorial nature of a resident's falls risks are explored and specific actions to manage these are identified and implemented. Failure to meet PDSA predictions about sharing risk reducing actions with staff and length of time to complete the tool prompted a focus on communication and the processes whereby the tool is completed. “Teach back” was employed to highlight communication difficulties and ultimately the introduction of Huddles out improved the flow of information about residents and informed the Falls Risk/Intervention tool. 5 PDSAs were completed and within them multiple tests of change. The improvement shift came following a root cause analysis of the nature & cause of one resident's falls and applying the tool & communication processes. The average falls rate fell from 49 per 1000 occupied bed days to 23.6 and was sustained because of the attention to the importance of communication. The aim was achieved with a 36.6% reduction in Falls rate. Care home residents are 3 times more likely to fall than their community dwelling peers and 10 times more likely to sustain a significant injury as a result. 2 A project commenced at a care home in Aberdeen with the aim of reducing the number of falls by 20% by 30th April 2016 using the model for improvement. Qualitative data was gathered to establish staff belief about falls and their level

  20. Optimal estimation reconstruction of the optical properties of a two-layered tissue phantom from time-resolved single-distance measurements

    Science.gov (United States)

    Martelli, Fabrizio; Del Bianco, Samuele; Spinelli, Lorenzo; Cavalieri, Stefano; Di Ninni, Paola; Binzoni, Tiziano; Jelzow, Alexander; Macdonald, Rainer; Wabnitz, Heidrun

    2015-11-01

    In this work, we have tested the optimal estimation (OE) algorithm for the reconstruction of the optical properties of a two-layered liquid tissue phantom from time-resolved single-distance measurements. The OE allows a priori information, in particular on the range of variation of fit parameters, to be included. The purpose of the present investigations was to compare the performance of OE with the Levenberg-Marquardt method for a geometry and real experimental conditions typically used to reconstruct the optical properties of biological tissues such as muscle and brain. The absorption coefficient of the layers was varied in a range of values typical for biological tissues. The reconstructions performed demonstrate the substantial improvements achievable with the OE provided a priori information is available. We note the extreme reliability, robustness, and accuracy of the retrieved absorption coefficient of the second layer obtained with the OE that was found for up to six fit parameters, with an error in the retrieved values of less than 10%. A priori information on fit parameters and fixed forward model parameters clearly improves robustness and accuracy of the inversion procedure.

  1. Improving the prediction accuracy of residue solvent accessibility and real-value backbone torsion angles of proteins by guided-learning through a two-layer neural network.

    Science.gov (United States)

    Faraggi, Eshel; Xue, Bin; Zhou, Yaoqi

    2009-03-01

    This article attempts to increase the prediction accuracy of residue solvent accessibility and real-value backbone torsion angles of proteins through improved learning. Most methods developed for improving the backpropagation algorithm of artificial neural networks are limited to small neural networks. Here, we introduce a guided-learning method suitable for networks of any size. The method employs a part of the weights for guiding and the other part for training and optimization. We demonstrate this technique by predicting residue solvent accessibility and real-value backbone torsion angles of proteins. In this application, the guiding factor is designed to satisfy the intuitive condition that for most residues, the contribution of a residue to the structural properties of another residue is smaller for greater separation in the protein-sequence distance between the two residues. We show that the guided-learning method makes a 2-4% reduction in 10-fold cross-validated mean absolute errors (MAE) for predicting residue solvent accessibility and backbone torsion angles, regardless of the size of database, the number of hidden layers and the size of input windows. This together with introduction of two-layer neural network with a bipolar activation function leads to a new method that has a MAE of 0.11 for residue solvent accessibility, 36 degrees for psi, and 22 degrees for phi. The method is available as a Real-SPINE 3.0 server in http://sparks.informatics.iupui.edu.

  2. Integration of Ground and Multi-Resolution Satellite Data for Predicting the Water Balance of a Mediterranean Two-Layer Agro-Ecosystem

    Directory of Open Access Journals (Sweden)

    Piero Battista

    2016-09-01

    Full Text Available The estimation of site water budget is important in Mediterranean areas, where it represents a crucial factor affecting the quantity and quality of traditional crop production. This is particularly the case for spatially fragmented, multi-layer agricultural ecosystems such as olive groves, which are traditional cultivations of the Mediterranean basin. The current paper aims at demonstrating the effectiveness of spatialized meteorological data and remote sensing techniques to estimate the actual evapotranspiration (ETA and the soil water content (SWC of an olive orchard in Central Italy. The relatively small size of this orchard (about 0.1 ha and its two-layer structure (i.e., olive trees and grasses require the integration of remotely sensed data with different spatial and temporal resolutions (Terra-MODIS, Landsat 8-OLI and Ikonos. These data are used to drive a recently proposed water balance method (NDVI-Cws and predict ETA and then site SWC, which are assessed through comparison with sap flow and soil wetness measurements taken in 2013. The results obtained indicate the importance of integrating satellite imageries having different spatio-temporal properties in order to properly characterize the examined olive orchard. More generally, the experimental evidences support the possibility of using widely available remotely sensed and ancillary datasets for the operational estimation of ETA and SWC in olive tree cultivation systems.

  3. Production of Steel Casts in Two-Layer Moulds with Alkaline Binders Part 1. Backing sand with the alkaline inorganic binder RUDAL

    Directory of Open Access Journals (Sweden)

    M. Holtzer

    2011-04-01

    Full Text Available Steel casts in Z.N. POMET were produced in moulds made of the moulding sand Floster. This sand did not have good knocking outproperties, required a significant binder addition (4.5-5.0 parts by weight, and the casting surface quality gave rise to clients objections.Therefore a decision of implementing two-layer moulds, in which the facing sand would consist of the moulding sand with an alkalineorganic binder while the backing sand would be made of the moulding sand with an inorganic binder also of an alkaline character - wasundertaken. The fraction of this last binder in the moulding sand mass would be smaller than that of the binder used up to now (waterglass. The application of two moulding sands of the same chemical character (highly alkaline should facilitate the reclamation processand improve the obtained reclaimed material quality, due to which it would be possible to increase the reclaim fraction in the mouldingsand (up to now it was 50%. The results of the laboratory investigations of sands with the RUDAL binder are presented in the paper.

  4. MHD Heat Transfer in Two-Layered Flow of Conducting Fluids through a Channel Bounded by Two Parallel Porous Plates in a Rotating System

    Science.gov (United States)

    Linga Raju, T.; Neela Rao, B.

    2016-08-01

    The paper aims to analyze the heat transfer aspects of a two-layered fluid flow in a horizontal channel under the action of an applied magnetic and electric fields, when the whole system is rotated about an axis perpendicular to the flow. The flow is driven by a common constant pressure gradient in the channel bounded by two parallel porous insulating plates, one being stationary and the other one oscillatory. The fluids in the two regions are considered electrically conducting, and are assumed to be incompressible with variable properties, namely, different densities, viscosities, thermal and electrical conductivities. The transport properties of the two fluids are taken to be constant and the bounding plates are maintained at constant and equal temperature. The governing partial differential equations are then reduced to the ordinary linear differential equations by using a two-term series. The temperature distributions in both fluid regions of the channel are derived analytically. The results are presented graphically to discuss the effect on the heat transfer characteristics and their dependence on the governing parameters, i.e., the Hartmann number, Taylor number, porous parameter, and ratios of the viscosities, heights, electrical and thermal conductivities. It is observed that, as the Coriolis forces become stronger, i.e., as the Taylor number increases, the temperature decreases in the two fluid regions. It is also seen that an increase in porous parameter diminishes the temperature distribution in both the regions.

  5. Physicochemical properties of hull-less barley fibre-rich fractions varying in particle size and their potential as functional ingredients in two-layer flat bread.

    Science.gov (United States)

    Izydorczyk, M S; Chornick, T L; Paulley, F G; Edwards, N M; Dexter, J E

    2008-05-15

    The performance of barley fibre-rich fractions (FRF), as high dietary fibre ingredients, in two-layer flat bread was investigated. In addition, the effects of particle size reduction by pin milling on functional properties of FRF were studied. FRF enriched in non-starch polysaccharides (β-glucans and arabinoxylans) were obtained by roller milling of hull-less barley. Pin milling (PM) of FRF significantly reduced their particle size, slightly increased the solubility of β-glucans and arabinoxylans, and increased the viscosity of water slurries containing FRF. The addition of 20% of barley FRF to wheat flour significantly increased dough water absorption and weakened the dough properties, as indicated by farinograph mixing curves, but the FRF-enriched doughs exhibited good handling characteristics at the dividing and sheeting stages. The appearance, diameter, layer separation, crumb, and aroma of the FRF-enriched flat breads were comparable to that of the control. The PM of FRF did not significantly affect the dough handling or the quality characteristics of flat breads. The addition of 20% of barley FRF to wheat flour flat bread provided substantial health benefits by significantly increasing the total and soluble dietary fibre contents and by decreasing starch digestibility.

  6. Second harmonic generation in anisotropic Langmuir-Blodgett films of N-docosyl-4-nitroaniline

    DEFF Research Database (Denmark)

    Geisler, T.; Rosenkilde, S.; Ramanujam, P.S.

    1992-01-01

    structure. Both of these observations are not common for Y-type LB films and the usual assumption of C(infinity nu) symmetry is therefore not valid. The results make us suggest that these LB films possess C(s) and C2-nu symmetry for mono- and multilayers, respectively. Theoretical expressions......Langmuir-Blodgett (LB) films of N-docosyl-4-nitroaniline have been made and their nonlinear optical properties studied by second harmonic generation (SHG) measurements. A significant enhancement of the intensity of the second harmonic of the 1.064-mu-m YAG was observed when a two layer Y-type film...

  7. Imitation of variable structural color in Paracheirodon innesi using colloidal crystal films.

    Science.gov (United States)

    Cong, Hailin; Yu, Bing; Zhao, Xiu Song

    2011-06-20

    Spacing variation of adjoining reflecting thin films in iridophore is responsible for the variable interference color in the paracheirodon innesi. On the basis of this phenomenon, colloidal crystal thin films with different structures are fabricated from monodisperse poly(styrene-methyl methacrylate-acrylic acid) (PSMA) colloids. The relationship between the colors and structures of the films is investigated and discussed according to the principle of light interference. A two-layer colloidal film having uniform color is researched and it displays diverse colors before and after swelling by styrene (St), which can be used to mimic the variable structural color of the paracheirodon innesi.

  8. Impact of Droplets on Inclined Flowing Liquid Films

    CERN Document Server

    Che, Zhizhao; Matar, Omar K

    2015-01-01

    The impact of droplets on an inclined falling liquid film is studied experimentally using high-speed imaging. The falling film is created on a flat substrate with controllable thicknesses and flow rates. Droplets with different sizes and speeds are used to study the impact process under various Ohnesorge and Weber numbers, and film Reynolds numbers. A number of phenomena associated with droplet impact are identified and analysed, such as bouncing, partial coalescence, total coalescence, and splashing. The effects of droplet size, speed, as well the film flow rate are studied culminating in the generation of an impact regime map. The analysis of the lubrication force acted on the droplet via the gas layer shows that a higher flow rate in the liquid film produces a larger lubrication force, slows down the drainage process, and increases the probability of droplet bouncing. Our results demonstrate that the flowing film has a profound effect on the droplet impact process and associated phenomena, which are marked...

  9. Falls and fear of falling in vertigo and balance disorders: A controlled cross-sectional study.

    Science.gov (United States)

    Schlick, Cornelia; Schniepp, Roman; Loidl, Verena; Wuehr, Max; Hesselbarth, Kristin; Jahn, Klaus

    2016-01-01

    Vertigo and dizziness are among the most prevalent symptoms in neurologic disorders. Although many of these patients suffer from postural instability and gait disturbances, there is only limited data on their risk of falling. We conducted a controlled cross-sectional study at the tertiary care outpatient clinic of the German Center for Vertigo and Balance Disorders using a self-administered questionnaire to assess falls, fall-related injuries, and fear of falling. The recruitment period was 6 months. A total of 569 patients (mean age 59.6 ± 17.1 years, 55% females) and 100 healthy participants were included (response rate > 90%). Dizzy patients with central balance disorders (Parkinsonian, cerebellar, and brainstem oculomotor syndromes) had the highest fall rates (> 50% recurrent fallers, odds ratio > 10). The rate of recurrent fallers was 30% in bilateral vestibular failure and peripheral neuropathy (odds ratio > 5). Patients with functional dizziness (somatoform or phobic vertigo) were concerned about falling but did not fall more often than healthy controls (odds ratio 0.87). Falls are common in patients presenting to a dizziness unit. Those with central syndromes are at risk of recurrent and injurious falling. Fall rates and fear of falling should be assessed in balance disorders and used to guide the regimen of rehabilitation therapy. The identification of risk factors would help provide protective measures to these groups of patients.

  10. Electrochemomechanical Behaviour of Bilayer and Trilayer Films with PEDOT and PPY Conducting Polymers

    DEFF Research Database (Denmark)

    Zainudeen, Umer L.; Careem, M.A.; Skaarup, Steen

    2008-01-01

    a constant load of 1.5 g. The cyclic voltammograms as well as the UV-visible spectra of PEDOT and PPy are very different, pointing towards the possibility of being able to separate the two layers experimentally – even when combined in a single film. Bilayer results show combined characteristics of each...

  11. Electrochemomechanical Behaviour of Bilayer and Trilayer Films with PEDOT and PPY Conducting Polymers

    DEFF Research Database (Denmark)

    Zainudeen, Umer L.; Careem, M.A.; Skaarup, Steen

    2008-01-01

    a constant load of 1.5 g. The cyclic voltammograms as well as the UV-visible spectra of PEDOT and PPy are very different, pointing towards the possibility of being able to separate the two layers experimentally – even when combined in a single film. Bilayer results show combined characteristics of each...

  12. Real time ellipsometric study of boron nitride thin film growth

    Energy Technology Data Exchange (ETDEWEB)

    Bertran, E.; Canillas, A.; Campmany, J.; El Kasmi, M.; Pascual, E.; Costa, J.; Andujar, J.L. [Univ. de Barcelona (Spain). Dept. de Fisica Aplicada i Electronica

    1996-12-31

    The authors present an in situ study of the growth of boron nitride thin films by real time ellipsometry. Films were produced in a PEVCD reactor by rf glow discharge decomposition of ammonia (pure) and diborane (1% in hydrogen), on in-Cr coated c-Si substrates placed either on the powered electrode or on the grounded electrode of the reactor. A fast phase-modulated ellipsometer performed the real time monitoring of the growth processes at 350 nm. The ellipsometric angle trajectories were obtained through an autocalibrated method, especially suitable for the in situ optical analysis of transparent thin films. The authors applied several thin film growth optical models (homogeneous, two-layer, surface roughness) to analyze parameters of the films such as refractive index, extinction coefficient, roughness and deposition rate. In all the cases studied, the two-layer model fits well with the ellipsometric measurements, but a more sophisticated model considering a variable refractive index could better describe these films.

  13. Sleep, insomnia and falls in elderly patients.

    Science.gov (United States)

    Stone, Katie L; Ensrud, Kristine E; Ancoli-Israel, Sonia

    2008-09-01

    Insomnia is common in older people and can be associated with significant daytime dysfunction. Sleep problems, and the medications used to treat them, may contribute to the risk of falls and fractures in this population; however, the independent effects of disturbed sleep or the risk of hypnotic use are not well understood. Data arising from the Study of Osteoporotic Fractures (SOF) cohort of elderly women have confirmed the link between sleep problems (measured subjectively or objectively) and an increased risk of falls after taking into account the use of insomnia medications (benzodiazepines) in a community-dwelling population of older women. The data also suggest that benzodiazepine use is associated with increased risk of falls, although this association is less clear-cut when insomnia/sleep problems are taken into consideration. The risk of falls should be considered when prescribing benzodiazepines in this population. So far no data exist concerning whether the effective treatment of insomnia in the elderly may help prevent falls. Furthermore, studies are warranted to evaluate the efficacy and safety of the non-benzodiazepine BZRAs (benzodiazepine receptor agonists) in relation to risk of falls. In addition, there is a need to include fall risk factors such as postural sway and reaction time as outcomes for trials of new insomnia treatments.

  14. Unexplained Falls Are Frequent in Patients with Fall-Related Injury Admitted to Orthopaedic Wards: The UFO Study (Unexplained Falls in Older Patients

    Directory of Open Access Journals (Sweden)

    Mussi Chiara

    2013-01-01

    Full Text Available To evaluate the incidence of unexplained falls in elderly patients affected by fall-related fractures admitted to orthopaedic wards, we recruited 246 consecutive patients older than 65 (mean age 82±7 years, range 65–101. Falls were defined “accidental” (fall explained by a definite accidental cause, “medical” (fall caused directly by a specific medical disease, “dementia-related” (fall in patients affected by moderate-severe dementia, and “unexplained” (nonaccidental falls, not related to a clear medical or drug-induced cause or with no apparent cause. According to the anamnestic features of the event, older patients had a lower tendency to remember the fall. Patients with accidental fall remember more often the event. Unexplained falls were frequent in both groups of age. Accidental falls were more frequent in younger patients, while dementia-related falls were more common in the older ones. Patients with unexplained falls showed a higher number of depressive symptoms. In a multivariate analysis a higher GDS and syncopal spells were independent predictors of unexplained falls. In conclusion, more than one third of all falls in patients hospitalized in orthopaedic wards were unexplained, particularly in patients with depressive symptoms and syncopal spells. The identification of fall causes must be evaluated in older patients with a fall-related injury.

  15. Unexplained Falls Are Frequent in Patients with Fall-Related Injury Admitted to Orthopaedic Wards: The UFO Study (Unexplained Falls in Older Patients).

    Science.gov (United States)

    Chiara, Mussi; Gianluigi, Galizia; Pasquale, Abete; Alessandro, Morrione; Alice, Maraviglia; Gabriele, Noro; Paolo, Cavagnaro; Loredana, Ghirelli; Giovanni, Tava; Franco, Rengo; Giulio, Masotti; Gianfranco, Salvioli; Niccolò, Marchionni; Andrea, Ungar

    2013-01-01

    To evaluate the incidence of unexplained falls in elderly patients affected by fall-related fractures admitted to orthopaedic wards, we recruited 246 consecutive patients older than 65 (mean age 82 ± 7 years, range 65-101). Falls were defined "accidental" (fall explained by a definite accidental cause), "medical" (fall caused directly by a specific medical disease), "dementia-related" (fall in patients affected by moderate-severe dementia), and "unexplained" (nonaccidental falls, not related to a clear medical or drug-induced cause or with no apparent cause). According to the anamnestic features of the event, older patients had a lower tendency to remember the fall. Patients with accidental fall remember more often the event. Unexplained falls were frequent in both groups of age. Accidental falls were more frequent in younger patients, while dementia-related falls were more common in the older ones. Patients with unexplained falls showed a higher number of depressive symptoms. In a multivariate analysis a higher GDS and syncopal spells were independent predictors of unexplained falls. In conclusion, more than one third of all falls in patients hospitalized in orthopaedic wards were unexplained, particularly in patients with depressive symptoms and syncopal spells. The identification of fall causes must be evaluated in older patients with a fall-related injury.

  16. Validation of the Saskatoon Falls Prevention Consortium's Falls Screening and Referral Algorithm

    Science.gov (United States)

    Lawson, Sara Nicole; Zaluski, Neal; Petrie, Amanda; Arnold, Cathy; Basran, Jenny

    2013-01-01

    ABSTRACT Purpose: To investigate the concurrent validity of the Saskatoon Falls Prevention Consortium's Falls Screening and Referral Algorithm (FSRA). Method: A total of 29 older adults (mean age 77.7 [SD 4.0] y) residing in an independent-living senior's complex who met inclusion criteria completed a demographic questionnaire and the components of the FSRA and Berg Balance Scale (BBS). The FSRA consists of the Elderly Fall Screening Test (EFST) and the Multi-factor Falls Questionnaire (MFQ); it is designed to categorize individuals into low, moderate, or high fall-risk categories to determine appropriate management pathways. A predictive model for probability of fall risk, based on previous research, was used to determine concurrent validity of the FSRI. Results: The FSRA placed 79% of participants into the low-risk category, whereas the predictive model found the probability of fall risk to range from 0.04 to 0.74, with a mean of 0.35 (SD 0.25). No statistically significant correlation was found between the FSRA and the predictive model for probability of fall risk (Spearman's ρ=0.35, p=0.06). Conclusion: The FSRA lacks concurrent validity relative to to a previously established model of fall risk and appears to over-categorize individuals into the low-risk group. Further research on the FSRA as an adequate tool to screen community-dwelling older adults for fall risk is recommended. PMID:24381379

  17. Estimation of the kinetic energy dissipation in fall-arrest system and manikin during fall impact.

    Science.gov (United States)

    Wu, John Z; Powers, John R; Harris, James R; Pan, Christopher S

    2011-04-01

    Fall-arrest systems (FASs) have been widely applied to provide a safe stop during fall incidents for occupational activities. The mechanical interaction and kinetic energy exchange between the human body and the fall-arrest system during fall impact is one of the most important factors in FAS ergonomic design. In the current study, we developed a systematic approach to evaluate the energy dissipated in the energy absorbing lanyard (EAL) and in the harness/manikin during fall impact. The kinematics of the manikin and EAL during the impact were derived using the arrest-force time histories that were measured experimentally. We applied the proposed method to analyse the experimental data of drop tests at heights of 1.83 and 3.35 m. Our preliminary results indicate that approximately 84-92% of the kinetic energy is dissipated in the EAL system and the remainder is dissipated in the harness/manikin during fall impact. The proposed approach would be useful for the ergonomic design and performance evaluation of an FAS. STATEMENT OF RELEVANCE: Mechanical interaction, especially kinetic energy exchange, between the human body and the fall-arrest system during fall impact is one of the most important factors in the ergonomic design of a fall-arrest system. In the current study, we propose an approach to quantify the kinetic energy dissipated in the energy absorbing lanyard and in the harness/body system during fall impact.

  18. Falls and falls efficacy: the role of sustained attention in older adults

    Directory of Open Access Journals (Sweden)

    O'Halloran Aisling M

    2011-12-01

    Full Text Available Abstract Background Previous evidence indicates that older people allocate more of their attentional resources toward their gait and that the attention-related changes that occur during aging increase the risk of falls. The aim of this study was to investigate whether performance and variability in sustained attention is associated with falls and falls efficacy in older adults. Methods 458 community-dwelling adults aged ≥ 60 years underwent a comprehensive geriatric assessment. Mean and variability of reaction time (RT, commission errors and omission errors were recorded during a fixed version of the Sustained Attention to Response Task (SART. RT variability was decomposed using the Fast Fourier Transform (FFT procedure, to help characterise variability associated with the arousal and vigilance aspects of sustained attention. The number of self-reported falls in the previous twelve months, and falls efficacy (Modified Falls Efficacy Scale were also recorded. Results Significant increases in the mean and variability of reaction time on the SART were significantly associated with both falls (p Conclusions Greater variability in sustained attention is strongly correlated with retrospective falls and to a lesser degree with reduced falls efficacy. This cognitive measure may provide a novel and valuable biomarker for falls in older adults, potentially allowing for early detection and the implementation of preventative intervention strategies.

  19. On the Motion of Falling Leaves

    CERN Document Server

    Razavi, Pedram

    2010-01-01

    This paper investigates the motion of falling leaves through modeling using papers and the corresponding data collected from more than four thousands experiments. Two series of experiments were designed in order to study the relationship between different parameters which can affect different paths of motion in leaves. In the first series of experiments, the shapes of the potential paths that falling papers can take were investigated as a whole. A new classification scheme was derived from these experiments, categorizing the motion of falling sheets of paper based on the deviation from the original point of release and the shape of the path they take on their descending journey. We believe this new classification scheme can be very useful with potential applications in various fields such as biology, meteorology, etc.; it can also build a foundation for further experiments. The second set of experiments was focused on the dynamics and shape of the motion of the falling paper itself. It was observed from these...

  20. Playful home training for falls prevention

    DEFF Research Database (Denmark)

    Jessen, Jari Due; Lund, Henrik Hautop

    2015-01-01

    Falling is a big issue among elderly, and prevention of falling is of big importance both for the individual and for society at large. In this paper we present a pilot study with fun exergaming equipment in private homes. The initial findings in the small pilot study suggests that this kind of tr...... barriers. Further, the paper describes how future research within the field will be structured.......Falling is a big issue among elderly, and prevention of falling is of big importance both for the individual and for society at large. In this paper we present a pilot study with fun exergaming equipment in private homes. The initial findings in the small pilot study suggests that this kind...

  1. Falling standards of research in India

    Digital Repository Service at National Institute of Oceanography (India)

    Varkey, M.J.

    Some points related to falling standards of research in India are discussed. The necessity for scientists to compete by publishing in international journals of high I. F.s (Impact Factor) is stressed. India lacks pioneers in science. Scientific...

  2. Usability testing of a fall prevention toolkit.

    Science.gov (United States)

    Keuter, Kayla R; Berg, Gina M; Hervey, Ashley M; Rogers, Nicole

    2015-05-01

    This study sought to evaluate a fall prevention toolkit, determine its ease of use and user satisfaction, and determine the preferred venue of distribution. Three forms of assessment were used: focus groups, usability testing, and surveys. Focus group participants were recruited from four locations: two rural health clinics and two urban centers. Usability testing participants were recruited from two rural health clinics. Survey questions included self-reported prior falls, current fall prevention habits, reaction to the toolkit, and demographics. Participants reported the toolkit was attractive, well-organized, and easy to use, but may contain too much information. Most participants admitted they would not actively use the toolkit on their own, but prefer having it introduced by a healthcare provider or in a social setting. Healthcare focuses on customer satisfaction; therefore, providers benefit from knowing patient preferred methods of learning fall prevention strategies.

  3. Effect of free fall on higher plants.

    Science.gov (United States)

    Gordon, S. A.

    1973-01-01

    The influence of exposure to the free-fall state on the orientation, morphogenesis, physiology, and radiation response of higher plants is briefly summarized. It is proposed that the duration of the space-flight experiments has been to brief to permit meaningful effects of free fall on general biochemistry, growth, and development to appear. However, two types of significant effect did occur. The first is on differential growth - i.e., tropism and epinasty - resulting from the absence of a normal geostimulus. For these phenomena it is suggested that ground-based experiments with the clinostat would suffice to mimic the effect of the free-fall state. The second is an apparent interaction between the radiation response and some flight condition, yielding an enhanced microspore abortion, a disturbed spindle function, and a stunting of stamen hairs. It is suggested that this apparent interaction may be derived from a shift in the rhythm of the cell cycle, induced by the free fall.

  4. Siena, 1794: History's Most Consequential Meteorite Fall

    Science.gov (United States)

    Marvin, U. B.

    1995-09-01

    In the mythos of meteoritics, the fall of stones at L'Aigle in Normandy at 1 p. m. on April 26, 1803, is commonly regarded as the event that turned skeptics into believers and opened the way for the new science. A strong case can be made, however, that the fall of stones at Siena at 7:00 p.m. on June 16, 1794, established the authenticity of meteorite falls and set in motion the reexaminations of entrenched beliefs that led to the founding of the new science. The Siena fall was heralded by the appearance of an extraordinarily high, dark cloud emitting smoke, sparks like rockets, and bolts of unusually slow-moving red lightning. With a tremendous explosion a shower of stones, ranging in weight from a few milligrams to 3 kg, fell southeast of Siena. This was the first meteorite fall to occur in the vicinity of a sizeable European city and the first to be witnessed by so many people, including English visitors, that the fall of the stones from the sky could not be denied. It also was the first fall to be seriously investigated by scholars, at several universities in Italy, who collected eye-witness reports and specimens and formulated hypotheses of origin. Their task was greatly complicated by the timing of the fall which occurred 18 hours after Mt. Vesuvius sprang into full eruption. Some believed that the two events were entirely coincidental; others thought that the stones either were ejecta from the volcano (which lay about 320 km to the southeast of Siena) or had consolidated in the fiery masses of dust and ash expelled by the mountain. No explanations seemed entirely satisfactory, but, in an age when the very possibility of falling stones had been decisively ruled out by savants of the Enlightenment, the well-observed fall at Siena opened a new dialog on this subject. The Siena fall occurred only two months after the publication in Riga and Leipzig of Ernst F. F. Chladni's book On the Origin of Ironmasses in which he concluded from historical records that

  5. Construction of Wave-free Potentials and Multipoles in a Two-layer Fluid Having Free-surface Boundary Condition with Higher-order Derivatives

    Institute of Scientific and Technical Information of China (English)

    Dilip Das

    2015-01-01

    There is a large class of problems in the field of fluid structure interaction where higher-order boundary conditions arise for a second-order partial differential equation. Various methods are being used to tackle these kind of mixed boundary-value problems associated with the Laplace’s equation (or Helmholtz equation) arising in the study of waves propagating through solids or fluids. One of the widely used methods in wave structure interaction is the multipole expansion method. This expansion involves a general combination of a regular wave, a wave source, a wave dipole and a regular wave-free part. The wave-free part can be further expanded in terms of wave-free multipoles which are termed as wave-free potentials. These are singular solutions of Laplace’s equation or two-dimensional Helmholz equation. Construction of these wave-free potentials and multipoles are presented here in a systematic manner for a number of situations such as two-dimensional non-oblique and oblique waves, three dimensional waves in two-layer fluid with free surface condition with higher order partial derivative are considered. In particular, these are obtained taking into account of the effect of the presence of surface tension at the free surface and also in the presence of an ice-cover modelled as a thin elastic plate. Also for limiting case, it can be shown that the multipoles and wave-free potential functions go over to the single layer multipoles and wave-free potential.

  6. A Two Layers Novel Low-Cost and Optimized Embedded Board Based on TMS320C6713 DSP and Spartan-3 FPGA

    Directory of Open Access Journals (Sweden)

    Bahram Rashidi

    2013-05-01

    Full Text Available This paper presents the design and implementation of a new low-cost and minimum embedded board based on TMS320C6713 (PYP 208-PIN (PQFP DSP and Spartan-3 (XCS400-4PQG208C FPGA in two layers with mount elements on two sides of the board. The proposed embedded board was developed satisfactorily for different applications such as data acquisition of sensor’s with serial port, control units, finite state machines, signal processing algorithms, navigation computing, Kalman filtering etc. Goal of the design was to implement as many as possible low-cost and minimum sizes of the board, also to receive input signals in a short time period and as real time. The board features are include: mount elements in two side of the board for minimization of the proposed board and also placed decoupling capacitors (by pass for the DSP and FPGA in bottom layer of board strictly below these two ICs because should be placed as close as possible to the power supply pins DSP and FPGA, GND polygon layer is used in total top layer and microcomputer ground for DSP & FPGA in bottom layer, use FPGA for two aim ones for implementation of glue logic total of board and interface between serial connectors, use three RS-232 serial port, one RS-422, and SPI serial port on FPGA, use MT48LC16M16A SDRAM-256MB(4*4MB*16, Am29LV400B Flash memory 4 Megabit (512 K x 8-Bit/256 K x 16-Bit and XCF02S configuration PROM. The size of the proposed embedded board is 11.1cm*17. 7cm so this board is optimized of aspect cost, performance, power, weight, and size.

  7. Supervised Learning of Two-Layer Perceptron under the Existence of External Noise — Learning Curve of Boolean Functions of Two Variables in Tree-Like Architecture —

    Science.gov (United States)

    Uezu, Tatsuya; Kiyokawa, Shuji

    2016-06-01

    We investigate the supervised batch learning of Boolean functions expressed by a two-layer perceptron with a tree-like structure. We adopt continuous weights (spherical model) and the Gibbs algorithm. We study the Parity and And machines and two types of noise, input and output noise, together with the noiseless case. We assume that only the teacher suffers from noise. By using the replica method, we derive the saddle point equations for order parameters under the replica symmetric (RS) ansatz. We study the critical value αC of the loading rate α above which the learning phase exists for cases with and without noise. We find that αC is nonzero for the Parity machine, while it is zero for the And machine. We derive the exponents barβ of order parameters expressed as (α - α C)bar{β} when α is near to αC. Furthermore, in the Parity machine, when noise exists, we find a spin glass solution, in which the overlap between the teacher and student vectors is zero but that between student vectors is nonzero. We perform Markov chain Monte Carlo simulations by simulated annealing and also by exchange Monte Carlo simulations in both machines. In the Parity machine, we study the de Almeida-Thouless stability, and by comparing theoretical and numerical results, we find that there exist parameter regions where the RS solution is unstable, and that the spin glass solution is metastable or unstable. We also study asymptotic learning behavior for large α and derive the exponents hat{β } of order parameters expressed as α - hat{β } when α is large in both machines. By simulated annealing simulations, we confirm these results and conclude that learning takes place for the input noise case with any noise amplitude and for the output noise case when the probability that the teacher's output is reversed is less than one-half.

  8. Long-term effects of dietary supplementation with an essential oil mixture on the growth and laying performance of two layer strains

    Directory of Open Access Journals (Sweden)

    Abdullah U. Çatli

    2012-01-01

    Full Text Available One thousand two hundred 1-day-old Lohmann LSL white and Lohmann Brown layer chickens were fed diets supplemented with either an antibiotic growth promoter (AGP or an herbal essential oil mixture (EOM till 58 wk of age to reveal the long-term effects of those additives on growth, performance and wholesome egg quality parameters. The study was arranged in a 2x3 factorial design with two layer strains and three feed additive regimens. Thus, the layer birds of both strains were randomly assigned to the three dietary treatments, i.e., standard basal diet (control, control with AGP (specifically, avilamycin, 10 mg/kg diet and control with EOM (24 mg/kg diet. The data regarding egg production were recorded between 22 to 58 weeks of age. Neither the dietary treatments nor the bird strain influenced the body weight and mortality of the birds in both the growing and laying period. AGP or EOM supplementation to the laying hen diet significantly increased the egg production rate and egg weight as compared to the control  diet alone, but egg mass output, feed consumption, and feed conversion ratio were not effected  by the dietary treatments. Neither dietary treatment created any statistically significantly differences in egg quality parameters with the exception of Haugh unit. The research findings have confirmed the beneficial effects of supplementation with feed-grade EOM on the laying rate and egg weight of both white and brown layers. Indeed, EOM, being a novel feed additive natural origin, proved to be as efficacious as AGP in promoting egg yield.

  9. Unsteady two-layered fluid flow of conducting fluids in a channel between parallel porous plates under transverse magnetic field in a rotating system

    Directory of Open Access Journals (Sweden)

    Linga Raju T.

    2016-05-01

    Full Text Available An unsteady MHD two-layered fluid flow of electrically conducting fluids in a horizontal channel bounded by two parallel porous plates under the influence of a transversely applied uniform strong magnetic field in a rotating system is analyzed. The flow is driven by a common constant pressure gradient in a channel bounded by two parallel porous plates, one being stationary and the other oscillatory. The two fluids are assumed to be incompressible, electrically conducting with different viscosities and electrical conductivities. The governing partial differential equations are reduced to the linear ordinary differential equations using two-term series. The resulting equations are solved analytically to obtain exact solutions for the velocity distributions (primary and secondary in the two regions respectively, by assuming their solutions as a combination of both the steady state and time dependent components of the solutions. Numerical values of the velocity distributions are computed for different sets of values of the governing parameters involved in the study and their corresponding profiles are also plotted. The details of the flow characteristics and their dependence on the governing parameters involved, such as the Hartmann number, Taylor number, porous parameter, ratio of the viscosities, electrical conductivities and heights are discussed. Also an observation is made how the velocity distributions vary with the rotating hydromagnetic interaction in the case of steady and unsteady flow motions. The primary velocity distributions in the two regions are seen to decrease with an increase in the Taylor number, but an increase in the Taylor number causes a rise in secondary velocity distributions. It is found that an increase in the porous parameter decreases both the primary and secondary velocity distributions in the two regions.

  10. INFLUENCE OF VARIATIONS OF THE CONDUCTIVITY OF UPPER LAYER OF TWO-LAYER SAMPLE ON OF PHASE INTRODUCED ELECTROMOTIVE FORCE OF SUPERIMPOSED TRANSDUCER OF EDDY CURRENT THICKNESS METER

    Directory of Open Access Journals (Sweden)

    A. V. Chernyshev

    2017-01-01

    Full Text Available In carrying out eddy current thickness measurement of two-layer conductive objects one from the interfering factors is the presence of variations in the value of the electrical conductivity of the material of the upper layer (coating when moving from point to point on the surface of object of control or when passing from one object of control to another. The aim of this work is to evaluate the accuracy of determining the thickness of the conductive coating disposed on a conducting ferromagnetic basis, using the phase method of eddy current testing. The reason of the error is variation of the electrical conductivity of the material of coating.Determination of the error is based on calculations using known analytical expressions for the loop with current of sinusoidal form arranged over the infinite half space with a covering as a thin layer. Selected in calculating electromagnetic parameters of coating and substrate approximately correspond to the case -chromium layer on a nickel base. Calculations are performed for different frequencies of current passed through coil.It is shown that at reduction of frequency of the current passes through the coil the error is reduced. The value of the lowest possible operating frequency of the excitation current is determined by the condition of absence influence on the phase introduced into the superimposed transducer emf variations in the thickness of the basis.To reduce the indicated error it is proposed to determine, on the basis of phase method at a relatively high frequency transducer current excitation, conductivity of the material of coating. After this, at a low frequency excitation current and using phase method, the coating thickness is determined, taking into consideration the previously determined value of the conductivity of coating. Also discussed ways to improve the accuracy of phase measurements in the MHz region of the excitation current frequency. 

  11. Using stable water isotopes in a two-layer soil moisture conceptual framework to understand transpiration dynamics in a semiarid shrubland

    Science.gov (United States)

    Szutu, D. J.; Papuga, S. A.; Wehr, R.

    2014-12-01

    Semiarid shrublands and other dryland ecosystems are highly sensitive to precipitation pulses. Because the frequency and magnitude of precipitation events have been projected to change for these ecosystems, the nature of these pulses and how they are distributed as moisture in the soil profile are also expected to change. Previous research has suggested that transpiration dynamics in drylands are associated with deep soil moisture, which accumulates after large rainfall events. Because transpiration is the productive component of evapotranspiration in that it is water used toward biomass accumulation, a hypothetical decrease in large rainfall events would have major consequences for the health and functioning of dryland ecosystems. Furthermore, as drylands account for nearly 40% of terrestrial biomes, these cascading changes have the potential to impact global water and carbon budgets. Still, in pulse-dependent dryland ecosystems, the relative contribution of transpiration to evapotranspiration and the temporal dynamics of this contribution are not well understood. The objective of this research is to better characterize the temporal dynamics of transpiration in dryland ecosystems. We present the relative contribution of transpiration to evapotranspiration over the course of a year from eddy covariance and sap flow measurements taken at a creosotebush-dominated shrubland ecosystem in southern Arizona. We analyze soil moisture and stable water isotopes within the context of a two-layer soil moisture conceptual framework in an attempt to identify the source water for transpiration. We use these results to explain the temporal dynamics of transpiration in this semiarid shrubland. Finally, we put our results in the context of regional climate projections to suggest how this dryland ecosystem might be impacted in the future. We expect our study will contribute to understanding where precipitation pulses are distributed in the soil moisture profile and when these pulses

  12. 异经多纬双层织物的生产%Production of Two-layer Fabric with Different Warp and Multiple Weft

    Institute of Scientific and Technical Information of China (English)

    郭凯军; 刘渊民; 邓红卫

    2012-01-01

    Design and key points in producing two-layer fabric with different warp and multiple wefts were discussed. The differences between warp and weft were larger,the production difficulties were larger than that of traditional fabric,two kinds of warp tension should be controlled well in warping. Slub yarn was dyed in sizing process to ensure correct reed-in. In weaving process, weft-inserting pressure of main nozzle was adjusted properly, loom tension was increased properly, loom processing was optimized rationally to prevent weft movement in back and weft shrinkage et al After adjusting processing, loom efficiency can be reached above 87% , storage rate of first-class product can be reached above 99. 8% , design and production demands can be reached.%探讨异经多纬双层织物的设计与生产技术要点.针对织物经纬纱差异、生产难度比传统织物大的特点,整经工序要控制好两种经纱的张力;浆纱时对其中的竹节纱进行上色,确保穿筘工序按工艺排列正确穿筘;织造工序合理调节主喷嘴引纬气压,适当增加上机张力,合理调试上机工艺,防止反面纬纱游移、纬缩等疵点造成染整后布面风格与质量变差.通过对工艺进行调整后,织机效率达到87%以上,产品入库一等品率达99.8%以上,满足了设计及生产要求.

  13. Sandbox modelling of sequential thrusting in a mechanically two-layered system and its implications in fold-and-thrust belts

    Science.gov (United States)

    Saha, Puspendu; Bose, Santanu; Mandal, Nibir

    2016-10-01

    Many fold-and-thrust belts display multi-storied thrust sequences, characterizing a composite architecture of the thrust wedges. Despite dramatic progress in sandbox modelling over the last three decades, our understanding of such composite thrust-wedge mechanics is limited and demands a re-visit to the problem of sequential thrusting in mechanically layered systems. This study offers a new approach to sandbox modelling, designed with a two-layered sandpack simulating a mechanically weak Coulomb layer, resting coherently upon a stronger Coulomb layer. Our experimental models reproduce strikingly similar styles of the multi-storied frontal thrust sequences observed in natural fold-and- thrust belts. The upper weak horizon undergoes sequential thrusting at a high spatial frequency, forming numerous, closely spaced frontal thrusts, whereas the lower strong horizon produces widely spaced thrusts with progressive horizontal shortening. This contrasting thrust progression behaviour gives rise to composite thrust architecture in the layered sandpack. We show the evolution of such composite thrust sequences as a function of frictional strength (μb) at the basal detachment and thickness ratio (Tr) between the weak and strong layers. For any given values of Tr and μb, the two thrust sequences progress at different rates; the closely-spaced, upper thrust sequence advances forelandward at a faster rate than the widely-spaced, lower thrust sequence. Basal friction (μb) has little effects on the vergence of thrusts in the upper weak layer; they verge always towards foreland, irrespective of Tr values. But, the lower strong layer develops back-vergent thrusts when μb is low (∼0.36). In our experiments, closely spaced thrusts in the upper sequence experience intense reactivation due to their interaction with widely spaced thrusts in the lower sequence. The interaction eventually affects the wedge topography, leading to two distinct parts: inner and outer wedges

  14. Fall of the Integrated Planning System

    Science.gov (United States)

    2012-05-17

    programs required to accomplish their missions. Henry Mintzberg identifies a basic planning model called the Core “Design School” Model.26 The Core...26 Henry Mintzberg , “The Rise and Fall of Strategic Planning: Reconceiving Roles for Planning, Plans, Planners,” New...21, 2011). Mintzberg , Henry. The Rise and Fall of Strategic Planning: Reconceiving Roles for Planning, Plans, Planners. New York: The Free Press

  15. Evaluation of the "medication fall risk score".

    Science.gov (United States)

    Yazdani, Cyrus; Hall, Scott

    2017-01-01

    Results of a study evaluating the predictive validity of a fall screening tool in hospitalized patients are reported. Administrative claims data from two hospitals were analyzed to determine the discriminatory ability of the "medication fall risk score" (RxFS), a medication review fall-risk screening tool that is designed for use in conjunction with nurse-administered tools such as the Morse Fall Scale (MFS). Through analysis of data on administered medications and documented falls in a population of adults who underwent fall-risk screening at hospital admission over a 15-month period (n = 33,058), the predictive value of admission MFS scores, alone or in combination with retrospectively calculated RxFS-based risk scores, was assessed. Receiver operating characteristic (ROC) curve analysis and net reclassification improvement (NRI) analysis were used to evaluate improvements in risk prediction with the addition of RxFS data to the prediction model. The area under the ROC curve for the predictive model for falls compromising both MFS and RxFS scores was computed as 0.8014, which was greater than the area under the ROC curve associated with use of the MFS alone (0.7823, p = 0.0030). Screening based on MFS scores alone had 81.25% sensitivity and 61.37% specificity. Combined use of RxFS and MFS scores resulted in 82.42% sensitivity and 66.65% specificity (NRI = 0.0587, p = 0.0003). Reclassification of fall risk based on coadministration of the MFS and the RxFS tools resulted in a modest improvement in specificity without compromising sensitivity. Copyright © 2017 by the American Society of Health-System Pharmacists, Inc. All rights reserved.

  16. Quantifying Temperature Effects on Fall Chinook Salmon

    Energy Technology Data Exchange (ETDEWEB)

    Jager, Yetta [ORNL

    2011-11-01

    The motivation for this study was to recommend relationships for use in a model of San Joaquin fall Chinook salmon. This report reviews literature pertaining to relationships between water temperature and fall Chinook salmon. The report is organized into three sections that deal with temperature effects on development and timing of freshwater life stages, temperature effects on incubation survival for eggs and alevin, and temperature effects on juvenile survival. Recommendations are made for modeling temperature influences for all three life stages.

  17. Syncope-related falls in the elderly

    Institute of Scientific and Technical Information of China (English)

    Rose Anne Kenny; Steve W Parry

    2005-01-01

    Age-related physiological impairments of heart rate, blood pressure and cerebral blood flow, in combination with comorbid conditions and concurrent medications, account for an increased susceptibility to syncope in older adults. Common causes of syncope are orthostatic hypotension, neurally-mediated syncope (including carotid sinus syndrome) and cardiac arrhythmias. A high proportion of older patients with cardiovascular syncope present with falls and deny loss of consciousness. Patients who are cognitively normal and have unexplained falls should have a detailed cardiovascular assessment.

  18. Falls incidence underestimates the risk of fall-related injuries in older age groups: A comparison with the FARE (Falls risk by exposure)

    NARCIS (Netherlands)

    Etman, A.; Wijlhuizen, G.J.; Heuvelen, M.J.G. van; Chorus, A.; Hopman-Rock, M.

    2012-01-01

    Background: up till now, the risk of falls has been expressed as falls incidence (i.e. the number of falls or fallers per 100 person-years). However, the risk of an accident or injury is the probability of having an accident or injury per unit of exposure. The FARE (Falls risk by Exposure) is a meas

  19. Falls incidence underestimates the risk of fall-related injuries in older age groups : a comparison with the FARE (Falls risk by Exposure)

    NARCIS (Netherlands)

    Etman, Astrid; Wijlhuizen, Gert Jan; van Heuvelen, Marieke J. G.; Chorus, Astrid; Hopman-Rock, Marijke

    2012-01-01

    Background: up till now, the risk of falls has been expressed as falls incidence (i.e. the number of falls or fallers per 100 person-years). However, the risk of an accident or injury is the probability of having an accident or injury per unit of exposure. The FARE ( Falls risk by Exposure) is a mea

  20. Get connected: New Fall Meeting technology

    Science.gov (United States)

    Moscovitch, Mirelle

    2012-11-01

    Kick off your 2012 Fall Meeting experience today by joining the Fall Meeting Community, an interactive Web-based community. Whether you are attending this year's Fall Meeting or are just interested in learning more, this site can help you connect with colleagues, learn about the groundbreaking research and amazing programming being presented in San Francisco, and plan your trip to the largest Earth and space science conference of the year. Available through the Fall Meeting Web site (http://fallmeeting.agu.org), the Community allows you to share your Fall Meeting experience like never before. You can join groups based on your interests, and each group includes a message board that allows you to ask questions, post comments, discuss presentations, and make plans with colleagues. You can also create your own groups and use the Community's robust search engine to find and connect with friends. And because the Fall Meeting Web site was improved for 2012 to allow for nearly seamless functionality on mobile devices, you can access much of the same Community functionality on the go.

  1. Comparison of real-life accidental falls in older people with experimental falls in middle-aged test subjects.

    Science.gov (United States)

    Kangas, M; Vikman, I; Nyberg, L; Korpelainen, R; Lindblom, J; Jämsä, T

    2012-03-01

    Falling is a common accident among older people. Automatic fall detectors are one method of improving security. However, in most cases, fall detectors are designed and tested with data from experimental falls in younger people. This study is one of the first to provide fall-related acceleration data obtained from real-life falls. Wireless sensors were used to collect acceleration data during a six-month test period in older people. Data from five events representing forward falls, a sideways fall, a backwards fall, and a fall out of bed were collected and compared with experimental falls performed by middle-aged test subjects. The signals from real-life falls had similar features to those from intentional falls. Real-life forward, sideways and backward falls all showed a pre impact phase and an impact phase that were in keeping with the model that was based on experimental falls. In addition, the fall out of bed had a similar acceleration profile as the experimental falls of the same type. However, there were differences in the parameters that were used for the detection of the fall phases. The beginning of the fall was detected in all of the real-life falls starting from a standing posture, whereas the high pre impact velocity was not. In some real-life falls, multiple impacts suggested protective actions. In conclusion, this study demonstrated similarities between real-life falls of older people and experimental falls of middle-aged subjects. However, some fall characteristics detected from experimental falls were not detectable in acceleration signals from corresponding heterogeneous real-life falls.

  2. SERS internship: Fall 1994 abstracts and research papers

    Energy Technology Data Exchange (ETDEWEB)

    Goldman, B.

    1994-12-01

    This publication is a collection of articles generated as a result of the fall 1994 Science and Engineering Research Semester program at Lawrence Livermore Laboratory. Research titles include: electrochemical cells in the reduction of hexavalent chromium; an automated system for studying the power distribution of electron beams; the mapping of novel genes to human chromosome 19; bolometer analysis comparisons; design and implementation of the LLNL Gigabit Testbed; in vitro synthesis and purification of PhIP-Deoxyguanosine and PhIP-DNA Covalent Complexes; pre-thymic somatic mutation leads to high mutant frequency hypoxanthine-guanine phosphoribosyl transferase gene; characterization of thin film multi-layers with magnetization curves and modeling of low angle X-ray diffraction data; total least squares; determining the water content of the Geysers Graywacke of northern California; a general approach to sharing data between scientific representations; nanomechanical properties of SiC thin films grown from C{sub 60} precursors; advanced information technology, a tool set for building clean database applications; the design of an automated electrolytic enrichment procedure for tritium; fluvial terrace dating using in-situ cosmogenic {sup 21}Ne; computer- aided mapping of stream channels beneath the Lawrence Livermore National Laboratory, Livermore, CA; X-ray spectroscopic technique for energetic electron transport studies in short-pulse laser/plasma interactions. Separate entries have been put in the energy data base for articles from this report. Selected papers are indexed separately for inclusion in the Energy Science and Technology Database.

  3. Martial arts fall techniques decrease the impact forces at the hip during sideways falling.

    Science.gov (United States)

    Groen, B E; Weerdesteyn, V; Duysens, J

    2007-01-01

    Falls to the side and those with impact on the hip are risky for hip fractures in the elderly. A previous study has indicated that martial arts (MA) fall techniques can reduce hip impact force, but the underlying mechanism is unknown. Furthermore, the high impact forces at the hand used to break the fall have raised concerns because of the risk for wrist fractures. The purpose of the study was to get insight into the role of hand impact, impact velocity, and trunk orientation in the reduction of hip impact force in MA techniques. Six experienced judokas performed sideways falls from kneeling height using three fall techniques: block with arm technique (control), MA technique with use of the arm to break the fall (MA-a), and MA technique without use of the arm (MA-na). The results showed that the MA-a and MA-na technique reduced the impact force by 27.5% and 30%, respectively. Impact velocity was significantly reduced in the MA falls. Trunk orientation was significantly less vertical in the MA-a falls. No significant differences were found between the MA techniques. It was concluded that the reduction in hip impact force was associated with a lower impact velocity and less vertical trunk orientation. Rolling after impact, which is characteristic for MA falls, is likely to contribute to the reduction of impact forces, as well. Using the arm to break the fall was not essential for the MA technique to reduce hip impact force. These findings provided support for the incorporation of MA fall techniques in fall prevention programs for elderly.

  4. Falls in spinocerebellar ataxias: Results of the EuroSCA Fall Study.

    Science.gov (United States)

    Fonteyn, Ella M R; Schmitz-Hübsch, Tanja; Verstappen, Carla C; Baliko, Laslo; Bloem, Bastiaan R; Boesch, Silvia; Bunn, Lisa; Charles, Perrine; Dürr, Alexandra; Filla, Allesandro; Giunti, Paola; Globas, Christoph; Klockgether, Thomas; Melegh, Bela; Pandolfo, Massimo; De Rosa, Anna; Schöls, Ludger; Timmann, Dagmar; Munneke, Marten; Kremer, Berry P H; van de Warrenburg, Bart P C

    2010-06-01

    To investigate the frequency, details, and consequences of falls in patients with autosomal dominant spinocerebellar ataxias (SCAs) and to derive specific disease-related risk factors that are associated with an increased fall frequency. Two hundred twenty-eight patients with SCA1, SCA2, SCA3, or SCA6, recruited from the EuroSCA natural history study, completed a fall questionnaire that assessed the frequency, consequences, and several details of falls in the previous 12 months. Relevant disease characteristics were retrieved from the EuroSCA registry. The database of the natural history study provided the ataxia severity scores as well as the number and nature of non-ataxia symptoms. Patients (73.6%) reported at least one fall in the preceding 12 months. There was a high rate of fall-related injuries (74%). Factors that were associated with a higher fall frequency included: disease duration, severity of ataxia, the presence of pyramidal symptoms, the total number of non-ataxia symptoms, and the genotype SCA3. Factors associated with a lower fall frequency were: the presence of extrapyramidal symptoms (more specifically dystonia of the lower limbs) and the genotype SCA2. The total number of non-ataxia symptoms and longer disease duration were independently associated with a higher fall frequency in a logistic regression analysis, while the presence of extrapyramidal symptoms was independently associated with a lower fall frequency. Our findings indicate that, in addition to more obvious factors that are associated with frequent falls, such as disease duration and ataxia severity, non-ataxia manifestations in SCA play a major role in the fall etiology of these patients.

  5. Tailored prevention of inpatient falls: development and usability testing of the fall TIPS toolkit.

    Science.gov (United States)

    Zuyev, Lyubov; Benoit, Angela N; Chang, Frank Y; Dykes, Patricia C

    2011-02-01

    Patient falls and fall-related injuries are serious problems in hospitals. The Fall TIPS application aims to prevent patient falls by translating routine nursing fall risk assessment into a decision support intervention that communicates fall risk status and creates a tailored evidence-based plan of care that is accessible to the care team, patients, and family members. In our design and implementation of the Fall TIPS toolkit, we used the Spiral Software Development Life Cycle model. Three output tools available to be generated from the toolkit are bed poster, plan of care, and patient education handout. A preliminary design of the application was based on initial requirements defined by project leaders and informed by focus groups with end users. Preliminary design partially simulated the paper version of the Morse Fall Scale currently used in hospitals involved in the research study. Strengths and weaknesses of the first prototype were identified by heuristic evaluation. Usability testing was performed at sites where research study is implemented. Suggestions mentioned by end users participating in usability studies were either directly incorporated into the toolkit and output tools, were slightly modified, or will be addressed during training. The next step is implementation of the fall prevention toolkit on the pilot testing units.

  6. Health care professionals' attitudes and compliance to clinical practice guidelines to prevent falls and fall injuries.

    Science.gov (United States)

    Stenberg, Marie; Wann-Hansson, Christine

    2011-06-01

    Clinical practice guidelines (CPGs) aimed at preventing falls and fall injuries have been shown to be effective in acute care hospitals. However, although CPGs are systematically developed and evidence-based tools, there has been a problem with their implementation in clinical practice. To describe influences on health care professionals' attitudes to CPGs for preventing falls and fall injuries. A qualitative approach was chosen and five focus group discussions were conducted, which included physicians, nurses, physiotherapists, and occupational therapists. The transcribed texts were analyzed using manifest and latent content analysis. Two main categories emerged: experiencing a course of events and influence of social factors. Experiencing a course of event included incidence of falls and fall injuries followed by negative consequences, which revealed benefits of using a CPG. Influence of social factors for implementation and compliance with the CPG was described as community obligations and organizational and individual resources. The findings confirm the complex process of implementation and compliance of CPGs for fall prevention. A relation between experiences of high incidence of falls with negative consequences and a positive attitude and compliance to CPGs appeared. To assure compliance and a positive attitude requires an obvious benefit of the CPG in reducing falls. Factors to overcome barriers to implementation and compliance seem to be a supportive leadership, systematic evaluations of the CPG outcome, and the facilitator role. Copyright ©2010 Sigma Theta Tau International.

  7. Polypharmacy and falls in older people: Balancing evidence-based medicine against falls risk.

    Science.gov (United States)

    Zia, Anam; Kamaruzzaman, Shahrul Bahyah; Tan, Maw Pin

    2015-04-01

    The term polypharmacy has negative connotations due to its association with adverse drug reactions and falls. This spectrum of adverse events widens when polypharmacy occurs among the already vulnerable geriatric population. To date, there is no consensus definition of polypharmacy, and diverse definitions have been used by various researchers, the most common being the consumption of multiple number of medications. Taking multiple medications is considered a risk factor for falls through the adverse effects of drug-drug or drug-disease interactions. Falls studies have determined that taking ≥ 4 drugs is associated with an increased incidence of falls, recurrent falls, and injurious falls. In light of existing evidence, careful and regular medication reviews are advised to reduce the effect of polypharmacy on falls. However, intervention studies on medication reviews and their effectiveness on falls reduction have been scarce. This article reviews and discusses the evidence behind polypharmacy and its association with falls among older individuals, and highlights important areas for future research.

  8. Self-reported preclinical mobility limitation and fall history as predictors of future falls in older women: prospective cohort study

    DEFF Research Database (Denmark)

    Mänty, Minna Regina; Heinonen, A; Viljanen, A

    2010-01-01

    We studied if self-reported preclinical mobility limitation, described as modification of task performance without perception of difficulty, predicts future falls in older women with and without fall history. Our results suggest that combined measure of self-reported preclinical mobility limitation...... and fall history may offer one possibility for inexpensive fall-risk evaluation in clinical practice. INTRODUCTION: We studied if self-reported preclinical mobility limitation predicts future falls in older women with and without fall history. METHODS: The study population consisted of 428 community...... mobility limitation. Fall history was recalled for previous 12 months and dichotomized. The incidence of future falls over 12 months was followed up with fall calendars. RESULTS: During the fall follow-up, a total of 440 falls were reported by 201 participants. Among those with fall history, women...

  9. Characteristics of daily life gait in fall and non fall-prone stroke survivors and controls.

    Science.gov (United States)

    Punt, Michiel; Bruijn, Sjoerd M; van Schooten, Kimberley S; Pijnappels, Mirjam; van de Port, Ingrid G; Wittink, Harriet; van Dieën, Jaap H

    2016-07-27

    Falls in stroke survivors can lead to serious injuries and medical costs. Fall risk in older adults can be predicted based on gait characteristics measured in daily life. Given the different gait patterns that stroke survivors exhibit it is unclear whether a similar fall-prediction model could be used in this group. Therefore the main purpose of this study was to examine whether fall-prediction models that have been used in older adults can also be used in a population of stroke survivors, or if modifications are needed, either in the cut-off values of such models, or in the gait characteristics of interest. This study investigated gait characteristics by assessing accelerations of the lower back measured during seven consecutive days in 31 non fall-prone stroke survivors, 25 fall-prone stroke survivors, 20 neurologically intact fall-prone older adults and 30 non fall-prone older adults. We created a binary logistic regression model to assess the ability of predicting falls for each gait characteristic. We included health status and the interaction between health status (stroke survivors versus older adults) and gait characteristic in the model. We found four significant interactions between gait characteristics and health status. Furthermore we found another four gait characteristics that had similar predictive capacity in both stroke survivors and older adults. The interactions between gait characteristics and health status indicate that gait characteristics are differently associated with fall history between stroke survivors and older adults. Thus specific models are needed to predict fall risk in stroke survivors.

  10. Fijian seasonal scourge of mango tree falls.

    Science.gov (United States)

    Gupta, Anuj; Reeves, Ben

    2009-12-01

    Mango tree falls are a frequent presentation at any health facility in the South Pacific. This study aims to identify (i) the number of admissions because of falls from mango trees; (ii) epidemiology; (iii) seasonal trend; (iv) injury profile; and (v) hospital care provided. Retrospective case review on all mango tree falls related injuries resulting in admissions at the Lautoka Hospital, Fiji during a 1-year period (2007). Patient records were analysed to identify specific injury patterns such as upper/lower limb fractures, spinal cord injury and head injury, caused by mango tree falls. Thirty-nine cases were identified. Eighty-two percent (n = 32) of the falls occurred in the mango season (June-November). Seventy-two percent (n = 28) of the patients were males and 28% (n = 11) were females. Seventy-six percent were aged 5-13 and only 21% were adults. Also, 77% (n = 30) of the patients were ethnic Fijians and 23% (n = 9) were Fijian-Indians. Sixty-four percent (n = 25) had closed fractures and 17% (n = 7) had open fractures. Fifty-six percent (n = 22) of the fractures were of the fore arm. There were two cases of spinal cord injury, four cases of head injury, one ICU admission and one death. Average hospital stay was 7.56 days. All these injuries were recreational and the majority in the urban setting. They were all avoidable.

  11. Accidents due to falls from roof slabs

    Directory of Open Access Journals (Sweden)

    Bruno Alves Rudelli

    Full Text Available CONTEXT AND OBJECTIVE Falls from the roof slabs of houses are accidents of high potential severity that occur in large Brazilian cities and often affect children and adolescents. The aims of this study were to characterize the factors that predispose towards this type of fall involving children and adolescents, quantify the severity of associated lesions and suggest preventive measures. DESIGN AND SETTING Descriptive observational prospective longitudinal study in two hospitals in the metropolitan region of São Paulo. METHODS Data were collected from 29 cases of falls from roof slabs involving children and adolescents between October 2008 and October 2009. RESULTS Cases involving males were more prevalent, accounting for 84%. The predominant age group was schoolchildren (7 to 12 years old; 44%. Leisure activities were most frequently being practiced on the roof slab at the time of the fall (86%, and flying a kite was the most prevalent game (37.9%. In 72% of the cases, the children were unaccompanied by an adult responsible for them. Severe conditions such as multiple trauma and traumatic brain injuries resulted from 79% of the accidents. CONCLUSION Falls from roof slabs are accidents of high potential severity, and preventive measures aimed towards informing parents and guardians about the dangers and risk factors associated with this type of accident are needed, along with physical protective measures, such as low walls around the slab and gates with locks to restrict free access to these places.

  12. Accidents due to falls from roof slabs.

    Science.gov (United States)

    Rudelli, Bruno Alves; Silva, Marcelo Valerio Alabarce da; Akkari, Miguel; Santili, Claudio

    2013-01-01

    CONTEXT AND OBJECTIVE Falls from the roof slabs of houses are accidents of high potential severity that occur in large Brazilian cities and often affect children and adolescents. The aims of this study were to characterize the factors that predispose towards this type of fall involving children and adolescents, quantify the severity of associated lesions and suggest preventive measures. DESIGN AND SETTING Descriptive observational prospective longitudinal study in two hospitals in the metropolitan region of São Paulo. METHODS Data were collected from 29 cases of falls from roof slabs involving children and adolescents between October 2008 and October 2009. RESULTS Cases involving males were more prevalent, accounting for 84%. The predominant age group was schoolchildren (7 to 12 years old; 44%). Leisure activities were most frequently being practiced on the roof slab at the time of the fall (86%), and flying a kite was the most prevalent game (37.9%). In 72% of the cases, the children were unaccompanied by an adult responsible for them. Severe conditions such as multiple trauma and traumatic brain injuries resulted from 79% of the accidents. CONCLUSION Falls from roof slabs are accidents of high potential severity, and preventive measures aimed towards informing parents and guardians about the dangers and risk factors associated with this type of accident are needed, along with physical protective measures, such as low walls around the slab and gates with locks to restrict free access to these places.

  13. Optical properties of PZT thin films deposited on a ZnO buffer layer

    OpenAIRE

    Schneider, T.; Leduc, D; Cardin, J.; LUPI, C; Barreau, N; Gundel, H.

    2007-01-01

    International audience; The optical properties of lead zirconate titanate (PZT) thin films deposited on ZnO were studied by m-lines spectroscopy. In order to retrieve the refractive index and the thickness of both layers from the m-lines spectra, we develop a numerical algorithm for the case of a two-layer system and show its robustness in the presence of noise. The sensitivity of the algorithm of the two-layer model allows us to relate the observed changes in the PZT refractive index to the ...

  14. Optical properties of PZT thin films deposited on a ZnO buffer layer

    OpenAIRE

    Schneider, T.; Leduc, D; Cardin, J.; LUPI, C; Barreau, N; Gundel, H.

    2015-01-01

    The optical properties of lead zirconate titanate (PZT) thin films deposited on ZnO were studied by m-lines spectroscopy. In order to retrieve the refractive index and the thickness of both layers from the m-lines spectra, we develop a numerical algorithm for the case of a two-layer system and show its robustness in the presence of noise. The sensitivity of the algorithm of the two-layer model allows us to relate the observed changes in the PZT refractive index to the PZT structural change du...

  15. Martial arts fall techniques decrease the impact forces at the hip during sideways falling.

    NARCIS (Netherlands)

    Groen, B.E.; Weerdesteijn, V.G.M.; Duysens, J.E.J.

    2007-01-01

    Falls to the side and those with impact on the hip are risky for hip fractures in the elderly. A previous study has indicated that martial arts (MA) fall techniques can reduce hip impact force, but the underlying mechanism is unknown. Furthermore, the high impact forces at the hand used to break the

  16. Older persons afraid of falling reduce physical activity to prevent outdoor falls

    NARCIS (Netherlands)

    Wijlhuizen, G.J.; Jong, R. de; Hopman-Rock, M.

    2007-01-01

    Objective.: The aim of this study was to test the assumption that the level of outdoor physical activity mediates the relationship between fear of falling and actual outdoor falls according to the Task Difficulty Homeostasis Theory. Method.: A prospective follow-up study of 10 months conducted in th

  17. Neurology Falls. Patient Falls Risk Assessment, Neurology Clinic, Johns Hopkins Hospital, Baltimore, MD

    Science.gov (United States)

    2009-07-06

    slip and fall injuries. The Journal of Forensic Science: pp.733-746. Hendrich, A., Nyhuis, A., Kippenbrock, T., & Soja , M.E. (1995). Hospital...shuffles. If patient is Neurology Falls 56 5. HFRM (Hendrich Fail Risk Assessment Model) (Hendrich, Nyhuis, Kippenbrock and Soja , 1995

  18. Martial arts fall techniques decrease the impact forces at the hip during sideways falling.

    NARCIS (Netherlands)

    Groen, B.E.; Weerdesteijn, V.G.M.; Duysens, J.E.J.

    2007-01-01

    Falls to the side and those with impact on the hip are risky for hip fractures in the elderly. A previous study has indicated that martial arts (MA) fall techniques can reduce hip impact force, but the underlying mechanism is unknown. Furthermore, the high impact forces at the hand used to break the

  19. Evaluation of Accelerometer-Based Fall Detection Algorithms on Real-World Falls

    NARCIS (Netherlands)

    Bagala, Fabio; Becker, Clemens; Cappello, Angelo; Chiari, Lorenzo; Aminian, Kamiar; Hausdorff, Jeffrey M.; Zijlstra, Wiebren; Klenk, Jochen

    2012-01-01

    Despite extensive preventive efforts, falls continue to be a major source of morbidity and mortality among elders. Real-time detection of falls and their urgent communication to a telecare center may enable rapid medical assistance, thus increasing the sense of security of the elderly and reducing s

  20. Older people's perception of and coping with falling, and their motivation for fall-prevention programmes

    DEFF Research Database (Denmark)

    Høst, Dorte; Hendriksen, Carsten; Borup, Ina

    2011-01-01

    This study aims to investigate older people's perceptions of and coping with falls, and what motivates them to join such programmes.......This study aims to investigate older people's perceptions of and coping with falls, and what motivates them to join such programmes....

  1. Falls study: Proprioception, postural stability, and slips.

    Science.gov (United States)

    Sohn, Jeehoon; Kim, Sukwon

    2015-01-01

    The present study evaluated effects of exercise training on the proprioception sensitivity, postural stability, and the likelihood of slip-induced falls. Eighteen older adults (6 in balance, 6 in weight, and 6 in control groups) participated in this study. Three groups met three times per week over the course of eight weeks. Ankle and knee proprioception sensitivities and postural stability were measured. Slip-induced events were introduced for all participants before and after training. The results indicated that, overall, strength and postural stability were improved only in the training group, although proprioception sensitivity was improved in all groups. Training for older adults resulted in decreased likelihood of slip-induced falls. The study suggested that proprioception can be improved by simply being active, however, the results suggested that training would aid older adults in reducing the likelihood of slip-induced falls.

  2. Elderly fall detection using SIFT hybrid features

    Science.gov (United States)

    Wang, Xiaoxiao; Gao, Chao; Guo, Yongcai

    2015-10-01

    With the tendency of aging society, countries all over the world are dealing with the demographic change. Fall had been proven to be of the highest fatality rate among the elderly. To realize the elderly fall detection, the proposed algorithm used the hybrid feature. Based on the rate of centroid change, the algorithm adopted VEI to offer the posture feature, this combined motion feature with posture feature. The algorithm also took advantage of SIFT descriptor of VEI(V-SIFT) to show more details of behaviors with occlusion. An improved motion detection method was proposed to improve the accuracy of front-view motion detection. The experimental results on CASIA database and self-built database showed that the proposed approach has high efficiency and strong robustness which effectively improved the accuracy of fall detection.

  3. Optimized analysis and experimental study for two-layer contact of crystalline silicon solar cells%晶体硅太阳电池双层电极优化分析与实验研究

    Institute of Scientific and Technical Information of China (English)

    李涛; 周春兰; 刘振刚; 赵雷; 李海玲; 刁宏伟; 王文静

    2012-01-01

    相对于单层电极结构,优化的前表面双层电极能够明显减小功率损失,改善晶体硅太阳电池的电学特性.本文对晶体硅太阳电池的双层电极进行了优化分析和实验研究.通过扫描电子显微镜观测将双层电极的截面抽象为更接近于实际的半椭圆型,建立了太阳电池前表面的双层电极模型,理论分析了双层电极的电学损失和光学损失.结合丝网印刷后光诱导电镀太阳电池的实验,得到了理论和实验上的最优化光诱导电镀增厚电极厚度与丝网印刷电极宽度的关系.所得到的理论和实验结果符合良好.由于并不涉及电极制备的具体技术,双层电极理论模型普遍适用于多种类型的双层电极结构.%Compared with single-layer contact,optimized two-layer contact of front side could diminish power losses distinctly and improve the electrical performance of crystalline silicon solar cell.In this paper,the optimized analysis and experimental study for two-layer contact of crystalline silicon solar cell are carried out.The model of two-layer contact is established by abstracting the crosssection of two-layer contact into semi-elliptical shape closer to the realistic situation according to the SEM observation.The electrical losses and the optical losses of two-layer contact are analyzed in theory.In combination with experimental screen-printed contact thickened by light-induced electroplating solar cell,the relationship between the optimum thickening contact thickness by light-induced electroplating and the screen-printed contact width is achieved in theory and experiment.The corresponding theory and experimental results are in good agreement with each other.Due to involving no concrete technology of contact preparation,the theoretical model of two-layer contact is generally appticable for many types of two-layer contact structures in consequence.

  4. Statistical modelling for falls count data.

    Science.gov (United States)

    Ullah, Shahid; Finch, Caroline F; Day, Lesley

    2010-03-01

    Falls and their injury outcomes have count distributions that are highly skewed toward the right with clumping at zero, posing analytical challenges. Different modelling approaches have been used in the published literature to describe falls count distributions, often without consideration of the underlying statistical and modelling assumptions. This paper compares the use of modified Poisson and negative binomial (NB) models as alternatives to Poisson (P) regression, for the analysis of fall outcome counts. Four different count-based regression models (P, NB, zero-inflated Poisson (ZIP), zero-inflated negative binomial (ZINB)) were each individually fitted to four separate fall count datasets from Australia, New Zealand and United States. The finite mixtures of P and NB regression models were also compared to the standard NB model. Both analytical (F, Vuong and bootstrap tests) and graphical approaches were used to select and compare models. Simulation studies assessed the size and power of each model fit. This study confirms that falls count distributions are over-dispersed, but not dispersed due to excess zero counts or heterogeneous population. Accordingly, the P model generally provided the poorest fit to all datasets. The fit improved significantly with NB and both zero-inflated models. The fit was also improved with the NB model, compared to finite mixtures of both P and NB regression models. Although there was little difference in fit between NB and ZINB models, in the interests of parsimony it is recommended that future studies involving modelling of falls count data routinely use the NB models in preference to the P or ZINB or finite mixture distribution. The fact that these conclusions apply across four separate datasets from four different samples of older people participating in studies of different methodology, adds strength to this general guiding principle.

  5. 面向个性化推荐的两层混合图模型%Hybrid Graph Model with Two Layers for Personalized Recommendation

    Institute of Scientific and Technical Information of China (English)

    张少中; 陈德人

    2009-01-01

    A hybrid graph model for personalized recom-mendation,which is based on small world network and Bayesian network,is presented.The hybrid graph model has two-layers.The bottom level means user's layer and the upper one means merchandise's layer.The user's layer is an undirected arcs graph,which describes the relation of the user's nodes by small world network.The undirected arcs inside the connected nodes of user's layer mean the similarity of the preference of users.These arcs are weighted by relational strength.The weight represents node's similarity or link's strength and intensity.Nodes in the same group are more similar to each other or more strongly connected.Users in a produce to others.It is connected by directed links,which means an implicated definition among merchandises,a user that purchase certain merchandise also tends to purchase another.The properties and content of merchandise can be used to show the similarity of the merchandise.The relations between user's layer and merchandise's layer are connected by directed links.The start nede of the directed links is a user node in user's layer belonging to some node group,which is gained by small world network.The end node of links is the node of some merchandise of the merchandise's layer.The directed links between the user's layer and the merchandise's layer are connected based on trade information of users.The strength of the relation between users and merchandises can be denoted by the probability parameter.The probability parameter shows a possibility of some users selecting for some merchandises. Firstly,algorithms for users clustering and for analysis of new user interest are presented to construct a hybrid graph model.Two important characteristic parameters,which are in small-world network,are introduced.These are characteristic path length and clustering coefficient.New user interest analysis is to judge which clustering group is the best match by calculating the distance of the new user node to

  6. 46 CFR 122.704 - Maintenance of falls.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Maintenance of falls. 122.704 Section 122.704 Shipping..., Maintenance, and Inspection of Lifesaving Equipment § 122.704 Maintenance of falls. (a) Each fall used in a... fall must be renewed when necessary due to deterioration or at internals of not more than 5...

  7. 46 CFR 131.550 - Maintenance of falls.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Maintenance of falls. 131.550 Section 131.550 Shipping..., Drills, and Inspections § 131.550 Maintenance of falls. (a) Each fall used with a launching appliance must be turned end for end at intervals of not more than 30 months. (b) Each fall used with a...

  8. 46 CFR 185.704 - Maintenance of falls.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Maintenance of falls. 185.704 Section 185.704 Shipping... of falls. (a) Each fall used in a launching appliance on a vessel must be turned end for end at intervals of not more than 30 months. (b) Each fall must be renewed when necessary due to deterioration...

  9. The growth-induced microstructural origin of the optical black state of Mg2NiHx thin films

    NARCIS (Netherlands)

    Westerwaal, R. J.; Borgschulte, A.; Lohstroh, W.; Dam, B.; Kooi, B.; ten Brink, Gert; Hopstaken, M. J. P.; Notten, P. H. L.

    2006-01-01

    Hydrogen absorption by a thin Mg2Ni film capped with Pd results in the nucleation of the Mg2NiH4 phase at the film/substrate interface. On further hydrogenation, a self-organized two-layer system consisting of a Mg2NiH0.3/Mg2NiH4 bottom-layer and a Mg2NiH0.3 top-layer is formed. This leads to an int

  10. The growth-induced microstructural origin of the optical black state of Mg2NiHx thin films

    NARCIS (Netherlands)

    Westerwaal, R. J.; Borgschulte, A.; Lohstroh, W.; Dam, B.; Kooi, B.; ten Brink, Gert; Hopstaken, M. J. P.; Notten, P. H. L.

    2006-01-01

    Hydrogen absorption by a thin Mg2Ni film capped with Pd results in the nucleation of the Mg2NiH4 phase at the film/substrate interface. On further hydrogenation, a self-organized two-layer system consisting of a Mg2NiH0.3/Mg2NiH4 bottom-layer and a Mg2NiH0.3 top-layer is formed. This leads to an int

  11. Electrical properties of ZnO thin films grown by MOCVD

    Energy Technology Data Exchange (ETDEWEB)

    Pagni, O. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Somhlahlo, N.N. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Weichsel, C. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Leitch, A.W.R. [Department of Physics, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa)]. E-mail: andrew.leitch@nmmu.ac.za

    2006-04-01

    We report on the electrical characterization of ZnO films grown by MOCVD on glass and sapphire substrates. After correcting our temperature variable Hall measurements by applying the standard two-layer model, which takes into account an interfacial layer, scattering mechanisms in the ZnO films were studied as well as donor activation energies determined. ZnO films grown at different oxygen partial pressures indicated the importance of growth conditions on the defect structure by means of their conductivities and conductivity activation energies.

  12. Seneca Falls: A Women's Demonstration for Peace.

    Science.gov (United States)

    Khan, Billie

    1984-01-01

    A reporter gives her personal impressions of the Seneca Falls Women's Encampment for a Future of Peace and Justice and the march by members of the encampment to the Seneca Army Depot. Confrontations between the demonstrators and conservative counterdemonstrators and the army response are also covered. (IS)

  13. TAP into Learning, Fall-Winter 2000.

    Science.gov (United States)

    Burns, Mary; Dimock, Vicki; Martinez, Danny

    2000-01-01

    This document consists of the final three issues of "TAP into Learning" (Technology Assistance Program). The double fall issue focuses on knowledge construction and on using multimedia applications in the classroom. Contents include: "Knowledge Under Construction"; "Hegel and the Dialectic"; "Implications for…

  14. AAAI 1991 Fall Symposium Series Reports

    OpenAIRE

    AAAI,

    1992-01-01

    The Association for the Advancement of Artificial Intelligence held its 1991 Fall Symposium Series on November 15-17 at the Asilomar Conference Center, Pacific Grove, California. This article contains summaries of the four symposia: Discourse Structure in Natural Language Understanding and Generation, Knowledge and Action at Social and Organizational Levels, Principles of Hybrid Reasoning, Sensory Aspects of Robotic Intelligence.

  15. Have a Safe and Healthy Fall

    Centers for Disease Control (CDC) Podcasts

    2010-10-14

    Fall is a great time to try new and healthy activities with your parents! Have a food tasting or a leaf raking contest! Whatever your plans, make sure to have fun and be safe!  Created: 10/14/2010 by CDC Office of Women’s Health.   Date Released: 10/14/2010.

  16. Community College Users' Report, Fall 1975.

    Science.gov (United States)

    Zimmer, A. L., Ed.

    This report was compiled from information supplied by instructors participating in the National Science Foundation's community college field test of PLATO IV--a computer-based system developed at the University of Illinois--during the fall semester of 1975. Represented here are the responses of instructors at five Illinois community colleges to…

  17. Riemann pendulum in free fall systems

    Science.gov (United States)

    Fargion, Daniele

    2016-07-01

    The possible detection in space and in different free fall system of the tidal effects via a Riemann pendulum rate, is considered. The possibility to perform such an experiment for educational purpouse by a Moire' or Holographic double exposure detection is described. The International Space Station may obtain high quality test of 3D Riemann pendulum effects.

  18. Milestones in gait, balance, and falling

    NARCIS (Netherlands)

    Nutt, J.G.; Horak, F.B.; Bloem, B.R.

    2011-01-01

    Gait, balance, and falls have become increasingly common topics of published articles in the Movement Disorders journal since its launch in 1986. This growth represents an increasing awareness of the importance of mobility to patients' quality of life. New methods have become available that allow fo

  19. Exploring fall training adaptations while walking.

    Science.gov (United States)

    Silver, Tobin A; Mokha, G Monique; Peacock, Corey A

    2016-06-13

    Trips are common in and out of the workplace with most people recovering to avoid a subsequent fall. However, when the recovery attempt fails, a fall can be detrimental. The purpose of this exploratory study was to examine adaptations to the elevating response during obstacle tripping while walking on a treadmill. Additionally, the possible transfer effects from adapted responses in the lab to the worksite are explored. Fourteen healthy participants that covered the general working age range (20-70 yrs.) were presented with two different types of tripping obstacles while walking. Elevating the foot over the obstacle was expected due to all trips being induced during early swing phase (first 33% of the swing phase). However, in addition to the elevating strategy, a novel "push" strategy was observed in all but three participants. The current study provided support that obstacle type influences the behavioral response after a trip. Therefore, obstacles that catch the shoe should be considered when designing functional fall programs. Furthermore, information from the current study is useful for establishing guidelines when developing a fall prevention program in the workplace.

  20. A new view on falling aprons

    NARCIS (Netherlands)

    Verhagen, H.J.; Van der Hoeven, M.; Thiel, B.

    2003-01-01

    In a flume of BallastHam Dredging a falling apron model has been constructed and loaded by current. The tests have been done with different rock sizes, different layer thickness of the top storage of the apron and two different gradings. In summary it was found that for both the narrow graded rock