Isogeometric variational multiscale large-eddy simulation of fully-developed turbulent flow over a wavy wall

KAUST Repository

Chang, Kyungsik

2012-09-01

We report on the isogeometric residual-based variational multiscale (VMS) large eddy simulation of a fully developed turbulent flow over a wavy wall. To assess the predictive capability of the VMS modeling framework, we compare its predictions against the results from direct numerical simulation (DNS) and large eddy simulation (LES) and, when available, against experimental measurements. We use C 1 quadratic B-spline basis functions to represent the smooth geometry of the sinusoidal lower wall and the solution variables. The Reynolds numbers of the flows considered are 6760 and 30,000 based on the bulk velocity and average channel height. The ratio of amplitude to wavelength (α/λ) of the sinusoidal wavy surface is set to 0.05. The computational domain is 2λ×1.05λ×λ in the streamwise, wall-normal and spanwise directions, respectively. For the Re=6760 case, mean averaged quantities, including velocity and pressure profiles, and the separation/reattachment points in the recirculation region, are compared with DNS and experimental data. The turbulent kinetic energy and Reynolds stress are in good agreement with benchmark data. Coherent structures over the wavy wall are observed in isosurfaces of the Q-criterion and show similar features to those previously reported in the literature. Comparable accuracy to DNS solutions is obtained with at least one order of magnitude fewer degrees of freedom. For the Re=30,000 case, good agreement was obtained for mean wall shear stress and velocity profiles compared with available LES results reported in the literature. © 2012 Elsevier Ltd.

Wavy channel Thin Film Transistor for area efficient, high performance and low power applications

KAUST Repository

Hanna, Amir

2014-06-01

We report a new Thin Film Transistor (TFT) architecture that allows expansion of the device width using wavy (continuous without separation) fin features - termed as wavy channel (WC) architecture. This architecture allows expansion of transistor width in a direction perpendicular to the substrate, thus not consuming extra chip area, achieving area efficiency. The devices have shown for a 13% increase in the device width resulting in a maximum 2.4x increase in \\'ON\\' current value of the WCTFT, when compared to planar devices consuming the same chip area, while using atomic layer deposition based zinc oxide (ZnO) as the channel material. The WCTFT devices also maintain similar \\'OFF\\' current value, similar to 100 pA, when compared to planar devices, thus not compromising on power consumption for performance which usually happens with larger width devices. This work offers a pragmatic opportunity to use WCTFTs as backplane circuitry for large-area high-resolution display applications without any limitation any TFT materials.

Zinc oxide integrated area efficient high output low power wavy channel thin film transistor

International Nuclear Information System (INIS)

Hanna, A. N.; Ghoneim, M. T.; Bahabry, R. R.; Hussain, A. M.; Hussain, M. M.

2013-01-01

We report an atomic layer deposition based zinc oxide channel material integrated thin film transistor using wavy channel architecture allowing expansion of the transistor width in the vertical direction using the fin type features. The experimental devices show area efficiency, higher normalized output current, and relatively lower power consumption compared to the planar architecture. This performance gain is attributed to the increased device width and an enhanced applied electric field due to the architecture when compared to a back gated planar device with the same process conditions

Zinc oxide integrated area efficient high output low power wavy channel thin film transistor

KAUST Repository

Hanna, Amir; Ghoneim, Mohamed T.; Bahabry, Rabab R.; Hussain, Aftab M.; Hussain, Muhammad Mustafa

2013-01-01

We report an atomic layer deposition based zinc oxide channel material integrated thin film transistor using wavy channel architecture allowing expansion of the transistor width in the vertical direction using the fin type features. The experimental devices show area efficiency, higher normalized output current, and relatively lower power consumption compared to the planar architecture. This performance gain is attributed to the increased device width and an enhanced applied electric field due to the architecture when compared to a back gated planar device with the same process conditions.

Zinc oxide integrated area efficient high output low power wavy channel thin film transistor

KAUST Repository

Hanna, Amir

2013-11-26

We report an atomic layer deposition based zinc oxide channel material integrated thin film transistor using wavy channel architecture allowing expansion of the transistor width in the vertical direction using the fin type features. The experimental devices show area efficiency, higher normalized output current, and relatively lower power consumption compared to the planar architecture. This performance gain is attributed to the increased device width and an enhanced applied electric field due to the architecture when compared to a back gated planar device with the same process conditions.

Nematic liquid crystals on sinusoidal channels: the zigzag instability.

Science.gov (United States)

Silvestre, Nuno M; Romero-Enrique, Jose M; Telo da Gama, Margarida M

2017-01-11

Substrates which are chemically or topographically patterned induce a variety of liquid crystal textures. The response of the liquid crystal to competing surface orientations, typical of patterned substrates, is determined by the anisotropy of the elastic constants and the interplay of the relevant lengths scales, such as the correlation length and the surface geometrical parameters. Transitions between different textures, usually with different symmetries, may occur under a wide range of conditions. We use the Landau-de Gennes free energy to investigate the texture of nematics in sinusoidal channels with parallel anchoring bounded by nematic-air interfaces that favour perpendicular (hometropic) anchoring. In micron size channels 5CB was observed to exhibit a non-trivial texture characterized by a disclination line, within the channel, which is broken into a zigzag pattern. Our calculations reveal that when the elastic anisotropy of the nematic does not favour twist distortions the defect is a straight disclination line that runs along the channel, which breaks into a zigzag pattern with a characteristic period, when the twist elastic constant becomes sufficiently small when compared to the splay and bend constants. The transition occurs through a twist instability that drives the defect line to rotate from its original position. The interplay between the energetically favourable twist distortions that induce the defect rotation and the liquid crystal anchoring at the surfaces leads to the zigzag pattern. We investigate in detail the dependence of the periodicity of the zigzag pattern on the geometrical parameters of the sinusoidal channels, which in line with the experimental results is found to be non-linear.

Simulation of a 3D Turbulent Wavy Channel based on the High-order WENO Scheme

Science.gov (United States)

Tsai, Bor-Jang; Chou, Chung-Chyi; Tsai, Yeong-Pei; Chuang, Ying Hung

2018-02-01

Passive interest turbulent drag reduction, effective means to improve air vehicle fuel consumption costs. Most turbulent problems happening to the nature and engineering applications were exactly the turbulence problem frequently caused by one or more turbulent shear flows. This study was operated with incompressible 3-D channels with cyclic wavy boundary to explore the physical properties of turbulence flow. This research measures the distribution of average velocity, instant flowing field shapes, turbulence and pressure distribution, etc. Furthermore, the systematic computation and analysis for the 3-D flow field was also implemented. It was aimed to clearly understand the turbulence fields formed by wavy boundary of tube flow. The purpose of this research is to obtain systematic structural information about the turbulent flow field and features of the turbulence structure are discussed.

Numerical study on the thermal and flow characteristics of periodically formed inner wavy structures in a cooling channel

Energy Technology Data Exchange (ETDEWEB)

Lee, Ju Chul; Park, Sang Hu; Son, Chang Min; Min, June Kee; Ha, Man Yeong [Pusan National University, Busan (Korea, Republic of); Cho, Jong Rae [Korea Maritime University, Busan (Korea, Republic of)

2015-09-15

In industrial fields of machine and aerospace, cooling systems consisting of channels are widely used to increase energy efficiency and prevent system overheat. In cooling channels, a reduced pressure drop, an enhanced heat transfer, and a short channel length are considered key design requirements for optimizing the total volume and weight of a system. In this work, we improved heat transfer efficiency by using milli-scale wavy structures inside the channel. By optimizing the inner structures through computational fluid dynamics analysis and Taguchi method, the Nusselt number increased by approximately 11.7% with a similar pressure drop compared with that of a normal channel for a Reynolds number of 1000.

New Results on Single-Channel Speech Separation Using Sinusoidal Modeling

DEFF Research Database (Denmark)

Mowlaee, Pejman; Christensen, Mads Græsbøll; Jensen, Søren Holdt

2011-01-01

We present new results on single-channel speech separation and suggest a new separation approach to improve the speech quality of separated signals from an observed mix- ture. The key idea is to derive a mixture estimator based on sinusoidal parameters. The proposed estimator is aimed at finding...... mixture estimator used in binary masks and the Wiener filtering approach, it is observed that the proposed method achieves an acceptable perceptual speech quality with less cross- talk at different signal-to-signal ratios. Moreover, the method is independent of pitch estimates and reduces the computational...... complexity of the separation by replacing the short-time Fourier transform (STFT) feature vectors of high dimensionality with sinusoidal feature vectors. We report separation results for the proposed method and compare them with respect to other benchmark methods. The improvements made by applying...

Sinusoidal voltage protocols for rapid characterisation of ion channel kinetics.

Science.gov (United States)

Beattie, Kylie A; Hill, Adam P; Bardenet, Rémi; Cui, Yi; Vandenberg, Jamie I; Gavaghan, David J; de Boer, Teun P; Mirams, Gary R

2018-03-24

Ion current kinetics are commonly represented by current-voltage relationships, time constant-voltage relationships and subsequently mathematical models fitted to these. These experiments take substantial time, which means they are rarely performed in the same cell. Rather than traditional square-wave voltage clamps, we fitted a model to the current evoked by a novel sum-of-sinusoids voltage clamp that was only 8 s long. Short protocols that can be performed multiple times within a single cell will offer many new opportunities to measure how ion current kinetics are affected by changing conditions. The new model predicts the current under traditional square-wave protocols well, with better predictions of underlying currents than literature models. The current under a novel physiologically relevant series of action potential clamps is predicted extremely well. The short sinusoidal protocols allow a model to be fully fitted to individual cells, allowing us to examine cell-cell variability in current kinetics for the first time. Understanding the roles of ion currents is crucial to predict the action of pharmaceuticals and mutations in different scenarios, and thereby to guide clinical interventions in the heart, brain and other electrophysiological systems. Our ability to predict how ion currents contribute to cellular electrophysiology is in turn critically dependent on our characterisation of ion channel kinetics - the voltage-dependent rates of transition between open, closed and inactivated channel states. We present a new method for rapidly exploring and characterising ion channel kinetics, applying it to the hERG potassium channel as an example, with the aim of generating a quantitatively predictive representation of the ion current. We fitted a mathematical model to currents evoked by a novel 8 second sinusoidal voltage clamp in CHO cells overexpressing hERG1a. The model was then used to predict over 5 minutes of recordings in the same cell in response to

Characterization of counter-rotating streamwise vortices in flat rectangular channel with one-sided wavy wall

KAUST Repository

Bouremel, Yann

2016-11-01

Particle Image Velocimetry (PIV) has been used to characterize the evolution of counter-rotating streamwise vortices in a rectangular channel with one sided wavy surface. The vortices were created by a uniform set of saw-tooth carved over the leading edge of a flat plate at the entrance of a flat rectangular channel with one-sided wavy wall. PIV measurements were taken over the spanwise and streamwise planes at different locations and at Reynolds number of 2500. Two other Reynolds numbers of 2885 and 3333 have also been considered for quantification purpose. Pairs of counter-rotating streamwise vortices have been shown experimentally to be centred along the spanwise direction at the saw-tooth valley where the vorticity ωz=0ωz=0. It has also been found that the vorticity ωzωz of the pairs of counter-rotating vortices decreases along the streamwise direction, and increases with the Reynolds number. Moreover, different quantifications of such counter-rotating vortices have been discussed such as their size, boundary layer, velocity profile and vorticity. The current study shows that the mixing due to the wall shear stress of counter-rotating streamwise vortices as well as their averaged viscous dissipation rate of kinetic energy decrease over flat and adverse pressure gradient surfaces while increasing over favourable pressure gradient surfaces. Finally, it was also demonstrated that the main direction of stretching is orientated at around 45° with the main flow direction.

Characterization of counter-rotating streamwise vortices in flat rectangular channel with one-sided wavy wall

KAUST Repository

Bouremel, Yann; Mitsudharmadi, Hatsari; Budiman, Alexander C.; Winoto, Sonny H.

2016-01-01

Particle Image Velocimetry (PIV) has been used to characterize the evolution of counter-rotating streamwise vortices in a rectangular channel with one sided wavy surface. The vortices were created by a uniform set of saw-tooth carved over the leading edge of a flat plate at the entrance of a flat rectangular channel with one-sided wavy wall. PIV measurements were taken over the spanwise and streamwise planes at different locations and at Reynolds number of 2500. Two other Reynolds numbers of 2885 and 3333 have also been considered for quantification purpose. Pairs of counter-rotating streamwise vortices have been shown experimentally to be centred along the spanwise direction at the saw-tooth valley where the vorticity ωz=0ωz=0. It has also been found that the vorticity ωzωz of the pairs of counter-rotating vortices decreases along the streamwise direction, and increases with the Reynolds number. Moreover, different quantifications of such counter-rotating vortices have been discussed such as their size, boundary layer, velocity profile and vorticity. The current study shows that the mixing due to the wall shear stress of counter-rotating streamwise vortices as well as their averaged viscous dissipation rate of kinetic energy decrease over flat and adverse pressure gradient surfaces while increasing over favourable pressure gradient surfaces. Finally, it was also demonstrated that the main direction of stretching is orientated at around 45° with the main flow direction.

Flow analysis for efficient design of wavy structured microchannel mixing devices

Science.gov (United States)

Kanchan, Mithun; Maniyeri, Ranjith

2018-04-01

Microfluidics is a rapidly growing field of applied research which is strongly driven by demands of bio-technology and medical innovation. Lab-on-chip (LOC) is one such application which deals with integrating bio-laboratory on micro-channel based single fluidic chip. Since fluid flow in such devices is restricted to laminar regime, designing an efficient passive modulator to induce chaotic mixing for such diffusion based flow is a major challenge. In the present work two-dimensional numerical simulation of viscous incompressible flow is carried out using immersed boundary method (IBM) to obtain an efficient design for wavy structured micro-channel mixing devices. The continuity and Navier-Stokes equations governing the flow are solved by fractional step based finite volume method on a staggered Cartesian grid system. IBM uses Eulerian co-ordinates to describe fluid flow and Lagrangian co-ordinates to describe solid boundary. Dirac delta function is used to couple both these co-ordinate variables. A tether forcing term is used to impose the no-slip boundary condition on the wavy structure and fluid interface. Fluid flow analysis by varying Reynolds number is carried out for four wavy structure models and one straight line model. By analyzing fluid accumulation zones and flow velocities, it can be concluded that straight line structure performs better mixing for low Reynolds number and Model 2 for higher Reynolds number. Thus wavy structures can be incorporated in micro-channels to improve mixing efficiency.

Development of a perpendicular vibration-induced electrical discharge machining process for fabrication of partially wavy inner structures

Energy Technology Data Exchange (ETDEWEB)

Lee, Ju Chul; Park, Sang Hu; Min, June Kee; Ha, Man Yeong; Shin, Bo Sung [Pusan National University, Busan (Korea, Republic of); Cho, Jong Rae [Korea Maritime University, Busan (Korea, Republic of)

2016-05-15

Heat transfer enhancement is an important issue in energy systems. To improve the efficiency of a cooling channel used inside injection molds, turbine blades, and high-temperature devices, channels with various shapes, such as wavy, elliptical, and twisted, have been studied. A cooling channel with a partially wavy inner structure has shown outstanding cooling performance despite a small increase in friction factor. However, generating a partially wavy inner structure inside a channel through conventional machining processes is not easy. To address this problem, we developed a new process called Perpendicular vibration-induced electrical discharge machining (PV-EDM). A specific electrode and one- and random-directional vibrating devices controlled by a pneumatic load were designed for the PV-EDM process. Experimental results showed that local shaping on the inner wall of a channel is possible, which confirmed the possibility of application of this process to actual industrial problems.

Development of Tollmien-Schlichting disturbances in the presence of laminar separation bubbles on an unswept infinite wavy wing

Science.gov (United States)

Thomas, Christian; Mughal, Shahid; Ashworth, Richard

2017-04-01

The effect of long-wavelength sinusoidal surface waviness on the development of Tollmien-Schlichting (TS) wave instabilities is investigated. The analysis is based on the compressible flow that forms over an unswept infinite wavy wing with surface variations of variable amplitude, wavelength, and phase. Boundary layer profiles are extracted directly from solutions of a Navier-Stokes solver, which allows a thorough parametric analysis to be undertaken. Many wavy surface configurations are examined that can be sufficient to establish localized pockets of separated flow. Linear stability analysis is undertaken using parabolized stability equations (PSE) and linearized Navier-Stokes (LNS) methods, and surface waviness is generally found to enhance unstable behavior. Results of the two schemes are compared and criteria for PSE to establish accurate solutions in separated flows are determined, which are based on the number of TS waves per wavelength of the surface deformation. Relationships are formulated, relating the instability variations to the surface parameters, which are consistent with previous observations regarding the growth of TS waves on a flat plate. Additionally, some long-wavelength surface deformations are found to stabilize TS disturbances.

Wavy channel thin film transistor architecture for area efficient, high performance and low power displays

KAUST Repository

Hanna, Amir

2013-12-23

We demonstrate a new thin film transistor (TFT) architecture that allows expansion of the device width using continuous fin features - termed as wavy channel (WC) architecture. This architecture allows expansion of transistor width in a direction perpendicular to the substrate, thus not consuming extra chip area, achieving area efficiency. The devices have shown for a 13% increase in the device width resulting in a maximum 2.5× increase in \\'ON\\' current value of the WCTFT, when compared to planar devices consuming the same chip area, while using atomic layer deposition based zinc oxide (ZnO) as the channel material. The WCTFT devices also maintain similar \\'OFF\\' current value, ~100 pA, when compared to planar devices, thus not compromising on power consumption for performance which usually happens with larger width devices. This work offers an interesting opportunity to use WCTFTs as backplane circuitry for large-area high-resolution display applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

MHD natural convection of hybrid nanofluid in an open wavy cavity

Science.gov (United States)

Ashorynejad, Hamid Reza; Shahriari, Alireza

2018-06-01

In this paper, natural convection heat transfer of Al2O3-Cu/water hybrid nanofluid within open wavy cavity and subjected to a uniform magnetic field is examined by adopting the lattice Boltzmann method scheme. The left wavy wall is heated sinusoidal, while the right wall is open and maintained to the ambient conditions. The top and the bottom horizontal walls are smooth and insulated against heat and mass. The influence of solid volume fraction of nanoparticles (φ = 0, 0.02, 0.04), Rayleigh number (Ra = 103, 104, 105), Hartmann number (Ha = 0, 30, 60, 90) and phase deviation (Φ = 0, π/4, π/2, 3π/4) are investigated on flow and heat transfer fields. The results proved that the Nusselt number decreases with the increase of the Hartmann number, but it increases by the increment of Rayleigh number and nanoparticle volume fraction. The magnetic field rises or falls the effect produced by the presence of nanoparticles with respect to Rayleigh number. At Ra = 103, the effect of the raising phase deviation on heat transfer is erratic while it has a positive role in the improvement of nanoparticles effect at Ra = 105.

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

International Nuclear Information System (INIS)

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

2013-01-01

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

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

KAUST Repository

Hanna, Amir

2016-01-01

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

Wavy Channel architecture thin film transistor (TFT) using amorphous zinc oxide for high-performance and low-power semiconductor circuits

KAUST Repository

Hanna, Amir; Hussain, Aftab M.; Hussain, Muhammad Mustafa

2015-01-01

We report a Wavy Channel (WC) architecture thin film transistor (TFT) for extended device width by integrating continuous vertical fin like features with lateral continuous plane in the substrate. For a WC TFT which has 50% larger device width, the enhancement in the output drive current is 100%, when compared to a conventional planar TFT consuming the same chip area. This current increase is attributed to both the extra width and enhanced field effect mobility due to corner effects. This shows the potential of WC architecture to boast circuit performance without the need for aggressive gate length scaling. © 2015 IEEE.

Wavy Channel architecture thin film transistor (TFT) using amorphous zinc oxide for high-performance and low-power semiconductor circuits

KAUST Repository

Hanna, Amir

2015-08-12

We report a Wavy Channel (WC) architecture thin film transistor (TFT) for extended device width by integrating continuous vertical fin like features with lateral continuous plane in the substrate. For a WC TFT which has 50% larger device width, the enhancement in the output drive current is 100%, when compared to a conventional planar TFT consuming the same chip area. This current increase is attributed to both the extra width and enhanced field effect mobility due to corner effects. This shows the potential of WC architecture to boast circuit performance without the need for aggressive gate length scaling. © 2015 IEEE.

Amorphous Zinc Oxide Integrated Wavy Channel Thin Film Transistor Based High Performance Digital Circuits

KAUST Repository

Hanna, Amir

2015-12-04

High performance thin film transistor (TFT) can be a great driving force for display, sensor/actuator, integrated electronics, and distributed computation for Internet of Everything applications. While semiconducting oxides like zinc oxide (ZnO) present promising opportunity in that regard, still wide area of improvement exists to increase the performance further. Here, we show a wavy channel (WC) architecture for ZnO integrated TFT which increases transistor width without chip area penalty, enabling high performance in material agnostic way. We further demonstrate digital logic NAND circuit using the WC architecture and compare it to the conventional planar architecture. The WC architecture circuits have shown 2× higher peak-to-peak output voltage for the same input voltage. They also have 3× lower high-to-low propagation delay times, respectively, when compared to the planar architecture. The performance enhancement is attributed to both extra device width and enhanced field effect mobility due to higher gate field electrostatics control.

Experimental study of fluid flow in the entrance of a sinusoidal channel

International Nuclear Information System (INIS)

Oviedo-Tolentino, F.; Romero-Mendez, R.; Hernandez-Guerrero, A.; Giron-Palomares, B.

2008-01-01

An experimental flow visualization study of the entrance section of channels formed with sinusoidal plates was made. The experiments were conducted in a water tunnel and a laser illuminated particle tracking was used as the technique of flow visualization. The geometric parameters of the plates were maintained constant while the distance between plates, phase angle, and the Reynolds number were varied during the experiments. The flow regimes that were found in the experiments are steady, unsteady and significantly-mixed flows. Instabilities of the flow first appear near the exit of the channel, and move closer to the inlet waves as the Reynolds number grows, but in the first wave from inlet the flow is always steady. The results show that, for all other parameters fixed, the Reynolds number at which unsteady flow first appears grows with the distance between plates. The phase angle that best promotes unsteady flow depends on the average distance between plates: for certain average distance between plates, there is a phase angle that best disturbs the flow. For the set of parameters used in this experiment, a channel with eight waves is sufficiently long and the flow features presented in the first eight waves of a longer channel will be similar to what was observed here

Area and energy efficient high-performance ZnO wavy channel thin-film transistor

KAUST Repository

Hanna, Amir

2014-09-01

Increased output current while maintaining low power consumption in thin-film transistors (TFTs) is essential for future generation large-area high-resolution displays. Here, we show wavy channel (WC) architecture in TFT that allows the expansion of the transistor width in the direction perpendicular to the substrate through integrating continuous fin features on the underlying substrate. This architecture enables expanding the TFT width without consuming any additional chip area, thus enabling increased performance while maintaining the real estate integrity. The experimental WCTFTs show a linear increase in output current as a function of number of fins per device resulting in (3.5×) increase in output current when compared with planar counterparts that consume the same chip area. The new architecture also allows tuning the threshold voltage as a function of the number of fin features included in the device, as threshold voltage linearly decreased from 6.8 V for planar device to 2.6 V for WC devices with 32 fins. This makes the new architecture more power efficient as lower operation voltages could be used for WC devices compared with planar counterparts. It was also found that field effect mobility linearly increases with the number of fins included in the device, showing almost \\\\(1.8×) enhancements in the field effect mobility than that of the planar counterparts. This can be attributed to higher electric field in the channel due to the fin architecture and threshold voltage shift. © 2014 IEEE.

Experimental investigation of wavy leading edges on rod-aerofoil interaction noise

Science.gov (United States)

Chen, Weijie; Qiao, Weiyang; Tong, Fan; Wang, Liangfeng; Wang, Xunnian

2018-05-01

Experimental studies are performed to investigate the effect of wavy leading edges on rod-aerofoil interaction noise in an open-jet anechoic wind tunnel. NACA 0012 aerofoils with straight and wavy leading edges (denoted by SLE and WLE, respectively) are embedded in the wake of a circular rod. The WLEs are in the form of sinusoidal profiles of amplitude, A, and wavelength, W. Parametric studies of the amplitude and wavelength characteristics are conducted to understand the effect of WLEs on noise reduction. It is observed that the sound power reduction level is sensitive to both the amplitude and wavelength of the WLEs. The WLE with the largest amplitude and smallest wavelength can achieve the most considerable noise reduction effect of up to 4 dB. The influences of rod diameter, d, and free-stream velocity, U0, on the noise reduction effect of the WLEs are also investigated. In addition, a parametric study of the influence of separating rod-aerofoil distance on the acoustic radiation of the SLE case and on the sound power reduction level of the WLE cases is performed. It is found that a critical spacing exists where the acoustic radiation and noise reduction can be divided into two different "modes".

Transitions between Taylor vortices and spirals via wavy Taylor vortices and wavy spirals

International Nuclear Information System (INIS)

Hoffmann, Ch; Altmeyer, S; Pinter, A; Luecke, M

2009-01-01

We present numerical simulations of closed wavy Taylor vortices and of helicoidal wavy spirals in the Taylor-Couette system. These wavy structures appearing via a secondary bifurcation out of Taylor vortex flow and out of spiral vortex flow, respectively, mediate transitions between Taylor and spiral vortices and vice versa. Structure, dynamics, stability and bifurcation behaviour are investigated in quantitative detail as a function of Reynolds numbers and wave numbers for counter-rotating as well as corotating cylinders. These results are obtained by solving the Navier-Stokes equations subject to axial periodicity for a radius ratio η=0.5 with a combination of a finite differences method and a Galerkin method.

Mathematical Models of the Sinusoidal Screen Family

Directory of Open Access Journals (Sweden)

Tajana Koren

2011-06-01

Full Text Available In this paper we will define a family of sinusoidal screening elements and explore the possibilities of their application in graphic arts, securities printing and design solutions in photography and typography editing. For this purpose mathematical expressions of sinusoidal families were converted into a Postscript language. The introduction of a random variable results in a countless number of various mutations which cannot be repeated without knowing the programming code itself. The use of the family of screens in protection of securities is thus of great importance. Other possible application of modulated sinusoidal screens is related to the large format color printing. This paper will test the application of sinusoidal screens in vector graphics, pixel graphics and typography. The development of parameters in the sinusoidal screen element algorithms gives new forms defined within screening cells with strict requirements of coverage implementation. Individual solutions include stochastic algorithms, as well as the autonomy of screening forms in regard to multicolor printing channels.

Aerodynamics of a thin airfoil flying over and in proximity to a wavy-wall surface. ; Lifting surface theory

Energy Technology Data Exchange (ETDEWEB)

Ando, S [Nagoya University, Nagoya (Japan); Ichikawa, M [Government Industrial Research Institute, Nagoya, Nagoya (Japan)

1991-05-04

Aerodynamic characteristics of a thin airfoil flying over and in proximity to a wavy-wall surface such as uneven ground or water surface were analyzed two-dimensionally by lifting surface theory in the simplest fundamental case only. The theoretical equation was simplified assuming that flow is inviscid and incompressible, all disturbances are sufficiently small, the wall surface is sinusoidal and rigid, and the wall moves in the same direction as free stream but with a constant velocity different from that of the stream. The equation was verified in the case where an airfoil with a constant angle-of-attack flies over a flat ground surface, and calculations were made with a set of important parameters such as mean airfoil height from the wall, wave length of the wall surface and the wall velocity. The whole effect of wavy wall proximity was divided into the first and second-order ground effects. The first one was just Kemp{prime}s upwash problem, and the second one was revealed through the present study which becomes significant for lower airfoil heights. 18 refs., 5 figs.

Glints from particulate media and wavy surfaces

International Nuclear Information System (INIS)

Borovoi, Anatoli; Konoshonkin, Alexander; Kolokolova, Ludmilla

2012-01-01

Glints are bright light spots created by particulate media like cirrus clouds, glaciers, and wavy water surfaces. They are seen around the specular reflection angle. In this paper, the glints from such scattering/reflecting media are described in a unified manner through the probability density for facet tilts. Various kinds of these probability densities for wavy surfaces are defined and classified. The concept of the differential scattering cross section (DSCS) for rough surfaces instead of the conventional bidirectional reflectance distribution function (BRDF) is introduced for characterization of the glints. The simple equations connecting the DSCS and the probability densities for facet tilts are derived. It is shown that the glints from particulate media and wavy surface are very similar at small incidence angles and they are significantly different at slant incidence. -- Highlights: ► Differential scattering cross section unifies particulate media and wavy surfaces. ► The glint pattern is a mapping of the probability density function for facet tilts. ► Shadowing is a crucial aspect of glint pattern formation. ► Glint patterns discriminate between the particulate media and wavy surfaces.

Visualization of pre-set vortices in boundary layer flow over wavy surface in rectangular channel

KAUST Repository

Budiman, Alexander Christantho; Mitsudharmadi, Hatsari; Bouremel, Yann; Winoto, Sonny H.; Low, H. T.

2014-01-01

structures on the cross-sectional plane normal to the wavy surface. To obtain uniform spanwise vortex wavelength which will result in uniform vortex size, two types of spanwise disturbances were used: a series of perturbation wires placed prior and normal

Turbulent boundary layer over 2D and 3D large-scale wavy walls

Science.gov (United States)

Chamorro, Leonardo P.; Hamed, Ali M.; Castillo, Luciano

2015-11-01

In this work, an experimental investigation of the developing and developed flow over two- and three-dimensional large-scale wavy walls was performed using high-resolution planar particle image velocimetry in a refractive-index-matching flume. The 2D wall is described by a sinusoidal wave in the streamwise direction with amplitude to wavelength ratio a/ λx = 0.05. The 3D wall is defined with an additional wave superimposed on the 2D wall in the spanwise direction with a/ λy = 0.1. The flow was characterized at Reynolds numbers of 4000 and 40000, based on the bulk velocity and the flume half height. Instantaneous velocity fields and time-averaged turbulence quantities reveal strong coupling between large-scale topography and the turbulence dynamics near the wall. Turbulence statistics show the presence of a well-structured shear layer that enhances the turbulence for the 2D wavy wall, whereas the 3D wall exhibits different flow dynamics and significantly lower turbulence levels, particularly for which shows about 30% reduction. The likelihood of recirculation bubbles, levels and spatial distribution of turbulence, and the rate of the turbulent kinetic energy production are shown to be severely affected when a single spanwise mode is superimposed on the 2D wall. POD analysis was also performed to further understand distinctive features of the flow structures due to surface topography.

Analysis of Passive Mixing in a Serpentine Microchannel with Sinusoidal Side Walls

Directory of Open Access Journals (Sweden)

Muhammad Usman Javaid

2017-12-01

Full Text Available Sample mixing is difficult in microfluidic devices because of laminar flow. Micromixers are designed to ensure the optimal use of miniaturized devices. The present study aims to design a chaotic-advection-based passive micromixer with enhanced mixing efficiency. A serpentine-shaped microchannel with sinusoidal side walls was designed, and three cases, with amplitude to wavelength (A/λ ratios of 0.1, 0.15, and 0.2 were investigated. Numerical simulations were conducted using the Navier–Stokes equations, to determine the flow field. The flow was then coupled with the convection–diffusion equation to obtain the species concentration distribution. The mixing performance of sinusoidal walled channels was compared with that of a simple serpentine channel for Reynolds numbers ranging from 0.1 to 50. Secondary flows were observed at high Reynolds numbers that mixed the fluid streams. These flows were dominant in the proposed sinusoidal walled channels, thereby showing better mixing performance than the simple serpentine channel at similar or less mixing cost. Higher mixing efficiency was obtained by increasing the A/λ ratio.

Natural convection in wavy enclosures with volumetric heat sources

International Nuclear Information System (INIS)

Oztop, H.F.; Varol, Y.; Abu-Nada, E.; Chamkha, A.

2011-01-01

In this paper, the effects of volumetric heat sources on natural convection heat transfer and flow structures in a wavy-walled enclosure are studied numerically. The governing differential equations are solved by an accurate finite-volume method. The vertical walls of enclosure are assumed to be heated differentially whereas the two wavy walls (top and bottom) are kept adiabatic. The effective governing parameters for this problem are the internal and external Rayleigh numbers and the amplitude of wavy walls. It is found that both the function of wavy wall and the ratio of internal Rayleigh number (Ra I ) to external Rayleigh number (Ra E ) affect the heat transfer and fluid flow significantly. The heat transfer is predicted to be a decreasing function of waviness of the top and bottom walls in case of (IRa/ERa)>1 and (IRa/ERa)<1. (authors)

Simulation of Guided Wave Interaction with In-Plane Fiber Waviness

Science.gov (United States)

Leckey, Cara A. C.; Juarez, Peter D.

2016-01-01

Reducing the timeline for certification of composite materials and enabling the expanded use of advanced composite materials for aerospace applications are two primary goals of NASA's Advanced Composites Project (ACP). A key a technical challenge area for accomplishing these goals is the development of rapid composite inspection methods with improved defect characterization capabilities. Ongoing work at NASA Langley is focused on expanding ultrasonic simulation capabilities for composite materials. Simulation tools can be used to guide the development of optimal inspection methods. Custom code based on elastodynamic finite integration technique is currently being developed and implemented to study ultrasonic wave interaction with manufacturing defects, such as in-plane fiber waviness (marcelling). This paper describes details of validation comparisons performed to enable simulation of guided wave propagation in composites containing fiber waviness. Simulation results for guided wave interaction with in-plane fiber waviness are also discussed. The results show that the wavefield is affected by the presence of waviness on both the surface containing fiber waviness, as well as the opposite surface to the location of waviness.

Interfacial condensation heat transfer for countercurrent steam-water wavy flow in a horizontal circular pipe

Energy Technology Data Exchange (ETDEWEB)

Lee, Kyung Won; Chun, Moon Hyun [Korea Advanced Institute of Science and Technolgy, Taejon (Korea, Republic of); Chu, In Cheol [KAERI, Taejon (Korea, Republic of)

2000-10-01

An experimental study of interfacial condensation heat transfer has been performed for countercurrent steam-water wavy flow in a horizontal circular pipe. A total of 105 local interfacial condensation heat transfer coefficients have been obtained for various combinations of test parameters. Two empirical Nusselt number correlations were developed and parametric effects of steam and water flow rates and the degree of water subcooling on the condensation heat transfer were examined. For the wavy interface condition, the local Nusselt number is more strongly sensitive to the steam Reynolds number than water Reynolds number as opposed to the case of smooth interface condition. Comparisons of the present circular pipe data with existing correlations showed that existing correlations developed for rectangular channels are not directly applicable to a horizontal circular pipe flow.

Enhance heat transfer in the channel with V-shaped wavy lower plate using liquid nanofluids

Directory of Open Access Journals (Sweden)

Azher M. Abed

2015-03-01

Full Text Available The heat transfer and flow characteristics in corrugated with V-shape lower plate using nanofluids are numerically studied. The computations are performed on uniform heat flux over a range of Reynolds number (Re 8000–20,000. The governing equations are numerically solved in the domain by a finite volume method (FVM using the k–ε standard turbulent model. Studies are carried out for different types of nanoparticles Al2O3,CuO, SiO2 and ZnO with different volume fractions in the range of 0–4%. Three different types of base fluid (water, glycerin, ethylene glycol are also examined. Results indicated that the average Nusselt number for nanofluids is greater than that of the base liquid. The SiO2 nanofluid yields the best heat transfer enhancement among all other type of nanofluids. Heat transfer enhancement increase with increases the volumetric concentration, but it is accompanied by increasing pressure drop values. Moreover, the average Nusselt number increases with an increase in Reynolds number and volume concentration. The SiO2–glycerin nanofluid has the highest Nusselt number compared with other base fluids. The present study shows that these V-shaped wavy channels have advantages by using nanofluids and thus serve as promising candidates for incorporation into efficient heat transfer devices.

Failure Behavior of Unidirectional Composites under Compression Loading: Effect of Fiber Waviness

Directory of Open Access Journals (Sweden)

Swaroop Narayanan Nair

2017-08-01

Full Text Available The key objective of this work is to highlight the effect of manufacturing-induced fiber waviness defects on the compressive failure of glass fiber-reinforced unidirectional specimens. For this purpose, in-plane, through-thickness waviness defects (with different waviness severities are induced during the manufacturing of the laminate. Numerical and experimental results show that the compressive strength of the composites decreases as the severity of the waviness defects increases. A reduction of up to 75% is noted with a wave severity of 0.075. Optical and scanning electron microscopy observations of the failed specimens reveal that kink-bands are created in the wavy regions and lead to failure.

Analytical solution to the problem of heat transfer in an MHD flow inside a channel with prescribed sinusoidal wall heat flux

International Nuclear Information System (INIS)

Zniber, K.; Oubarra, A.; Lahjomri, J.

2005-01-01

An MHD laminar flow through a two dimensional channel subjected to a uniform magnetic field and heated at the walls of the conduit over the whole length with a sinusoidal heat flux of vanishing mean value or not, is studied analytically. General expressions of the temperature distribution and of the local and mean Nusselt numbers are obtained by using the technique of linear operators in the case of negligible Joule and viscous dissipation and by taking into account the axial conduction effect. The principal results show that an increase of the local Nusselt number with Hartmann number is observed, and, far from the inlet section, the average heat transfer between the fluid and the walls shows a significant improvement at all values of Hartmann number used when the frequency of the prescribed sinusoidal wall heat flux is increasing in the case of vanishing mean value of the heat flux and this is true especially at low Peclet numbers

Numerical study of Wavy Blade Section for Wind Turbines

DEFF Research Database (Denmark)

Kobæk, C. M.; Hansen, Martin Otto Laver

2016-01-01

than a flipper having a smooth trailing edge and thus could be potentially beneficial when catching food. A thorough literature study of the Wavy Blade concept is made and followed by CFD computations of two wavy blade geometries and a comparison with their baseline S809 airfoil at conditions more...

Hydrodynamic characteristics for flow around wavy wings with different wave lengths

Directory of Open Access Journals (Sweden)

Mi Jeong Kim

2012-12-01

Full Text Available The present study numerically investigates the effect of the wavy leading edge on hydrodynamic characteristics for the flow of rectangular wings with the low aspect ratio of 1.5. Five different wave lengths at fixed wavy amplitude have been considered. Numerical simulations are performed at a wide range of the angle of attack (0° ≤α ≤ 40° at one Reynolds number of 106. The wavy wings considered in this study did not experience enough lift drop to be defined as the stall, comparing with the smooth wing. However, in the pre-stall region, the wavy wings reveal the considerable loss of the lift, compared to the smooth wing. In the post-stall, the lift coefficients of the smooth wing and the wavy wings are not much different. The pressure coefficient, limiting streamlines and the iso-surface of the spanwise vorticity are also highlighted to examine the effect of the wave length on the flow structures.

The waviness of the extratropical jet and daily weather extremes

Science.gov (United States)

Röthlisberger, Matthias; Martius, Olivia; Pfahl, Stephan

2016-04-01

In recent years the Northern Hemisphere mid-latitudes have experienced a large number of weather extremes with substantial socio-economic impact, such as the European and Russian heat waves in 2003 and 2010, severe winter floods in the United Kingdom in 2013/2014 and devastating winter storms such as Lothar (1999) and Xynthia (2010) in Central Europe. These have triggered an engaged debate within the scientific community on the role of human induced climate change in the occurrence of such extremes. A key element of this debate is the hypothesis that the waviness of the extratropical jet is linked to the occurrence of weather extremes, with a wavier jet stream favouring more extremes. Previous work on this topic is expanded in this study by analyzing the linkage between a regional measure of jet waviness and daily temperature, precipitation and wind gust extremes. We show that indeed such a linkage exists in many regions of the world, however this waviness-extremes linkage varies spatially in strength and sign. Locally, it is strong only where the relevant weather systems, in which the extremes occur, are affected by the jet waviness. Its sign depends on how the frequency of occurrence of the relevant weather systems is correlated with the occurrence of high and low jet waviness. These results go beyond previous studies by noting that also a decrease in waviness could be associated with an enhanced number of some weather extremes, especially wind gust and precipitation extremes over western Europe.

Generation of Customizable Micro-wavy Pattern through Grayscale Direct Image Lithography.

Science.gov (United States)

He, Ran; Wang, Shunqiang; Andrews, Geoffrey; Shi, Wentao; Liu, Yaling

2016-02-23

With the increasing amount of research work in surface studies, a more effective method of producing patterned microstructures is highly desired due to the geometric limitations and complex fabricating process of current techniques. This paper presents an efficient and cost-effective method to generate customizable micro-wavy pattern using direct image lithography. This method utilizes a grayscale Gaussian distribution effect to model inaccuracies inherent in the polymerization process, which are normally regarded as trivial matters or errors. The measured surface profiles and the mathematical prediction show a good agreement, demonstrating the ability of this method to generate wavy patterns with precisely controlled features. An accurate pattern can be generated with customizable parameters (wavelength, amplitude, wave shape, pattern profile, and overall dimension). This mask-free photolithography approach provides a rapid fabrication method that is capable of generating complex and non-uniform 3D wavy patterns with the wavelength ranging from 12 μm to 2100 μm and an amplitude-to-wavelength ratio as large as 300%. Microfluidic devices with pure wavy and wavy-herringbone patterns suitable for capture of circulating tumor cells are made as a demonstrative application. A completely customized microfluidic device with wavy patterns can be created within a few hours without access to clean room or commercial photolithography equipment.

Generation of Customizable Micro-wavy Pattern through Grayscale Direct Image Lithography

Science.gov (United States)

He, Ran; Wang, Shunqiang; Andrews, Geoffrey; Shi, Wentao; Liu, Yaling

2016-02-01

With the increasing amount of research work in surface studies, a more effective method of producing patterned microstructures is highly desired due to the geometric limitations and complex fabricating process of current techniques. This paper presents an efficient and cost-effective method to generate customizable micro-wavy pattern using direct image lithography. This method utilizes a grayscale Gaussian distribution effect to model inaccuracies inherent in the polymerization process, which are normally regarded as trivial matters or errors. The measured surface profiles and the mathematical prediction show a good agreement, demonstrating the ability of this method to generate wavy patterns with precisely controlled features. An accurate pattern can be generated with customizable parameters (wavelength, amplitude, wave shape, pattern profile, and overall dimension). This mask-free photolithography approach provides a rapid fabrication method that is capable of generating complex and non-uniform 3D wavy patterns with the wavelength ranging from 12 μm to 2100 μm and an amplitude-to-wavelength ratio as large as 300%. Microfluidic devices with pure wavy and wavy-herringbone patterns suitable for capture of circulating tumor cells are made as a demonstrative application. A completely customized microfluidic device with wavy patterns can be created within a few hours without access to clean room or commercial photolithography equipment.

Numerical simulation of turbulent convective flow over wavy terrain

Science.gov (United States)

Dörnbrack, A.; Schumann, U.

1993-09-01

By means of a large-eddy simulation, the convective boundary layer is investigated for flows over wavy terrain. The lower surface varies sinusoidally in the downstream direction while remaining constant in the other. Several cases are considered with amplitude δ up to 0.15 H and wavelength λ of H to 8 H, where H is the mean fluid-layer height. At the lower surface, the vertical heat flux is prescribed to be constant and the momentum flux is determined locally from the Monin-Obukhov relationship with a roughness length z o=10-4 H. The mean wind is varied between zero and 5 w *, where w * is the convective velocity scale. After rather long times, the flow structure shows horizontal scales up to 4 H, with a pattern similar to that over flat surfaces at corresponding shear friction. Weak mean wind destroys regular spatial structures induced by the surface undulation at zero mean wind. The surface heating suppresses mean-flow recirculation-regions even for steep surface waves. Short surface waves cause strong drag due to hydrostatic and dynamic pressure forces in addition to frictional drag. The pressure drag increases slowly with the mean velocity, and strongly with δ/ H. The turbulence variances increase mainly in the lower half of the mixed layer for U/w *>2.

A study on waviness induced vibration of ball bearings based on signal coherence theory

Science.gov (United States)

Liu, Wentao; Zhang, Yun; Feng, Zhi-Jing; Zhao, Jing-Shan; Wang, Dongfeng

2014-11-01

This paper focuses on the effects of waviness on vibration of ball bearings. An experimental analysis method is developed by adopting signal coherence theory of multiple-inputs/single-output (MISO) system. The inputs are waviness excitations of the inner and outer races, and the output is vibration response of the outer ring. Waviness excitation signals are first derived from the manufacturing deviations, and found to be strongly coherent in low frequency range. Virtual input signals are then introduced by the method of orthogonalization. In both cases of vibration acceleration and speed responses, the cumulated virtual input-output coherence function verifies that the first peak region of vibration spectrum is mainly induced by the waviness excitations. In order to distinguish the contributions of the inner and outer races, coherence functions of the virtual inputs with real inputs are calculated, and the results indicate that the outer race waviness contributes more to vibration than the inner race waviness does in the example. Further, a multi-body dynamic model is constructed and employed to frequency response analyses. It is discovered that the waviness induced spectral peak frequency is close to the natural frequency of bearing.

On the study of wavy leading-edge vanes to achieve low fan interaction noise

Science.gov (United States)

Tong, Fan; Qiao, Weiyang; Xu, Kunbo; Wang, Liangfeng; Chen, Weijie; Wang, Xunnian

2018-04-01

The application of wavy leading-edge vanes to reduce a single-stage axial fan noise is numerically studied. The aerodynamic and acoustic performance of the fan is numerically investigated using a hybrid unsteady Reynolds averaged Navier-Stokes (URANS)/acoustic analogy method (Goldstein equations). First, the hybrid URANS/Goldstein method is developed and successfully validated against experiment results. Next, numerical simulations are performed to investigate the noise reduction effects of the wavy leading-edge vanes. The aerodynamic and acoustic performance is assessed for a fan with vanes equipped with two different wavy leading-edge profiles and compared with the performance of conventional straight leading-edge vanes. Results indicate that a fan with wavy leading-edge vanes produces lower interaction noise than the baseline fan without a significant loss in aerodynamic performance. In fact, it is demonstrated that wavy leading-edge vanes have the potential to lead to both aerodynamic and acoustic improvements. The two different wavy leading-edge profiles are shown to successfully reduce the fan tone sound power level by 1.2 dB and 4.3 dB, respectively. Fan efficiency is also improved by about 1% with one of the tested wavy leading-edge profiles. Large eddy simulation (LES) is also performed for a simplified fan stage model to assess the effects of wavy leading-edge vanes on the broadband fan noise. Results indicate that the overall sound power level of a fan can be reduced by about 4 dB with the larger wavy leading-edge profile. Finally, the noise reduction mechanisms are investigated and analysed. It is found that the wavy leading-edge profiles can induce significant streamwise vorticity around the leading-edge protuberances and reduce pressure fluctuations (especially at locations of wavy leading-edge hills) and unsteady forces on the stator vanes. The underlying mechanism of the reduced pressure fluctuations is also discussed by examining the magnitude

Natural convection of nanofluid in a wavy cavity in the presence of magnetic field on variable heat surface temperature

Energy Technology Data Exchange (ETDEWEB)

Javaherdeh, Korosh; Moslemi, Mehdi; Shahbazi, Mona [University of Guilan, Rasht (Iran, Islamic Republic of)

2017-04-15

A numerical analysis has been performed to investigate the laminar natural convection heat characteristics in a wavy cavity filled with CuO/water nanofluid. One of the sinusoidal walls (BC) is at the volatile high temperature and the opposite wavy surface is at a stable low temperature and the two other walls are considered flat and insulated while the uniform magnetic field is considered. Performing the analysis, the governing equations are given in terms of the stream function-vorticity formulation. In order to solve the nondimensionalized equations, discretizing with second-order accurate central difference method is performed then the successive under relaxation method with appropriate boundary conditions is considered. To validate the numerical model, various comparisons with previously published studies have been conducted and the results are in a good agreement. The main objective is to survey the effects of the Rayleigh number, Hartmann number, and nanoparticles volume fraction on the fluid flow and heat transfer characteristics. The results are illustrated in contours of stream function, constant temperature, and Nusselt number. The results show that the presence of the magnetic field the local Nusselt number decreases at the hot wall. Moreover, the enhancement in the heat transfer performance increases with an increasing nanoparticle concentration. However, for all values of Rayleigh number, the presence of nanoparticles leads to significant enhancement in heat transfer and the increase of Rayleigh number causes the heat transfer mechanism to change from conduction to convection.

Effect of Collector Aspect Ratio on the Thermal Performance of Wavy Finned Absorber Solar Air Heater

OpenAIRE

Abhishek Priyam; Prabha Chand

2016-01-01

A theoretical investigation on the effect of collector aspect ratio on the thermal performance of wavy finned absorber solar air heaters has been performed. For the constant collector area, the various performance parameters have been calculated for plane and wavy finned solar air heaters. It has been found that the performance of wavy finned solar air heater improved with the increase in the collector aspect ratio. The performance of wavy finned solar air heater has been found 30 percent hig...

An Experimental Study of the Influence of in-Plane Fiber Waviness on Unidirectional Laminates Tensile Properties

Science.gov (United States)

Zhao, Cong; Xiao, Jun; Li, Yong; Chu, Qiyi; Xu, Ting; Wang, Bendong

2017-12-01

As one of the most common process induced defects of automated fiber placement, in-plane fiber waviness and its influences on mechanical properties of fiber reinforced composite lack experimental studies. In this paper, a new approach to prepare the test specimen with in-plane fiber waviness is proposed in consideration of the mismatch between the current test standard and actual fiber trajectory. Based on the generation mechanism of in-plane fiber waviness during automated fiber placement, the magnitude of in-plane fiber waviness is characterized by axial compressive strain of prepreg tow. The elastic constants and tensile strength of unidirectional laminates with in-plane fiber waviness are calculated by off-axis and maximum stress theory. Experimental results show that the tensile properties infade dramatically with increasing magnitude of the waviness, in good agreement with theoretical analyses. When prepreg tow compressive strain reaches 1.2%, the longitudinal tensile modulus and strength of unidirectional laminate decreased by 25.5% and 57.7%, respectively.

Performance comparisons of enhanced tubes with discrete and wavy disruption shapes

Energy Technology Data Exchange (ETDEWEB)

Arman, B.; Rabas, T.J.

1993-08-01

This paper presents comparisons of the friction factors and heat-transfer coefficients obtained with enhanced tubes with transverse discrete and almost transverse wavy two-dimensional disruptions. Both experimental data and numerical predictions were used for the comparisons. For the latter a two-layer turbulence model incorporated in a body-fitted, finite-volume method was used. The disruption shape, discrete or wavy, depends on the manufacturing process. If an extrusion process is used, discrete disruptions (ribs) of various profiles are obtained that are separated from each other by a flat or unaltered inside diameter. If a spirally indenting process is used, a wavy proflie is obtained with a continuously varying inside diameter between two adjacent disruption peaks. These disruptions are transverse or almost transverse to the tube axis and separated by a distance that exceeds the reattachment length. Based on these comparisons, the following conclusions are obtained: (1) the disruption shape is not an important correlating parameter for discrete disruptions, (2) only the friction factor is influenced by the shape for wavy disruptions, and (3) there are major differences between both the friction-factor and heat-transfer performance of discrete and wavy disruptions with the same maximum disruption height and spacing. However, the most important finding is that the groove radius of spirally indented tubes should be increased because of the substantial reduction of the friction factor but only a small decrease in the thermal performance. Additional comparisons of predicted results were made to obtain a fundamental understanding of the influence of these different shapes.

Numerical simulations and linear stability analysis of a boundary layer developed on wavy surfaces

Science.gov (United States)

Siconolfi, Lorenzo; Camarri, Simone; Fransson, Jens H. M.

2015-11-01

The development of passive methods leading to a laminar to turbulent transition delay in a boundary layer (BL) is a topic of great interest both for applications and academic research. In literature it has been shown that a proper and stable spanwise velocity modulation can reduce the growth rate of Tollmien-Schlichting (TS) waves and delay transition. In this study, we investigate numerically the possibility of obtaining a stabilizing effect of the TS waves through the use of a spanwise sinusoidal modulation of a flat plate. This type of control has been already successfully investigated experimentally. An extensive set of direct numerical simulations is carried out to study the evolution of a BL flow developed on wavy surfaces with different geometric characteristics, and the results will be presented here. Moreover, since this configuration is characterized by a slowly-varying flow field in streamwise direction, a local stability analysis is applied to define the neutral stability curves for the BL flow controlled by this type of wall modifications. These results give the possibility of investigating this control strategy and understanding the effect of the free parameters on the stabilization mechanism.

Performance evaluation of a wavy-fin heat sink for power electronics

International Nuclear Information System (INIS)

Lorenzini, Marco; Fabbri, Giampietro; Salvigni, Sandro

2007-01-01

The almost daily increase in dissipated power per unit area of electronic components sets higher and higher demands on the performance of the heat sinks. These must not only be able to dissipate high heat fluxes, but must also keep costs to a minimum and exhibit a reliable behaviour. In this paper a novel, modular heat sink consisting of elements with wavy fin profile which can be pressed together to construct the component is presented. Its performance under steady-state conditions are assessed for the case of forced convection in terms of velocity distribution in the channels and global thermal resistance. Configurations with uniform and non-uniform heat flux are studied and some considerations are made as to the influence of the spacers between fan and heat sink proper

Sinusoidal Representation of Acoustic Signals

Science.gov (United States)

Honda, Masaaki

Sinusoidal representation of acoustic signals has been an important tool in speech and music processing like signal analysis, synthesis and time scale or pitch modifications. It can be applicable to arbitrary signals, which is an important advantage over other signal representations like physical modeling of acoustic signals. In sinusoidal representation, acoustic signals are composed as sums of sinusoid (sine wave) with different amplitudes, frequencies and phases, which is based on the timedependent short-time Fourier transform (STFT). This article describes the principles of acoustic signal analysis/synthesis based on a sinusoid representation with focus on sine waves with rapidly varying frequency.

A Retrospective on Modulated Wavy Vortex Flow

OpenAIRE

Gorman, Michael; Swinney, Harry

2009-01-01

A fluid dynamics video of the Modulated Wavy Vortex Flow state of Taylor-Couette flow with the outer cylinder fixed is presented. This state precedes the transition to turbulence, which is more gradual than that for other fluid systems.

Sinusoidal obstruction syndrome.

Science.gov (United States)

Valla, Dominique-Charles; Cazals-Hatem, Dominique

2016-09-01

Sinusoidal obstruction syndrome (SOS) is characterized by damage to small hepatic vessels affecting particularly sinusoidal endothelium. Damaged sinusoids can be associated with a partial or complete occlusion of small hepatic veins, hence the previous denomination of hepatic veno-occlusive disease (VOD). Exposure to certain exogenous toxins appears to be specific to this condition and is frequently included in its definition. Typical histopathological features of SOS in a liver biopsy specimen are presented in the text. The purpose of this article is to provide an overview on the different entities corresponding to this general definition. Such entities include: (i) liver disease related to pyrrolizidine alcaloids; (ii) liver injury related to conditioning for hematopoietic stem cell transplantation; (iii) vascular liver disease occurring in patients treated with chemotherapy for liver metastasis of colorectal cancer; and (iv) other liver diseases related to toxic agents. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Analysis of Entropy Generation in Flow of Methanol-Based Nanofluid in a Sinusoidal Wavy Channel

Directory of Open Access Journals (Sweden)

Muhammad Qasim

2017-10-01

Full Text Available The entropy generation due to heat transfer and fluid friction in mixed convective peristaltic flow of methanol-Al2O3 nano fluid is examined. Maxwell’s thermal conductivity model is used in analysis. Velocity and temperature profiles are utilized in the computation of the entropy generation number. The effects of involved physical parameters on velocity, temperature, entropy generation number, and Bejan number are discussed and explained graphically.

Sinusoids theory and technological applications

CERN Document Server

Kythe, Prem K

2014-01-01

A Complete Treatment of Current Research Topics in Fourier Transforms and Sinusoids Sinusoids: Theory and Technological Applications explains how sinusoids and Fourier transforms are used in a variety of application areas, including signal processing, GPS, optics, x-ray crystallography, radioastronomy, poetry and music as sound waves, and the medical sciences. With more than 200 illustrations, the book discusses electromagnetic force and sychrotron radiation comprising all kinds of waves, including gamma rays, x-rays, UV rays, visible light rays, infrared, microwaves, and radio waves. It also covers topics of common interest, such as quasars, pulsars, the Big Bang theory, Olbers' paradox, black holes, Mars mission, and SETI.The book begins by describing sinusoids-which are periodic sine or cosine functions-using well-known examples from wave theory, including traveling and standing waves, continuous musical rhythms, and the human liver. It next discusses the Fourier series and transform in both continuous and...

Natural convection of Al2O3-water nanofluid in a wavy enclosure

Science.gov (United States)

Leonard, Mitchell; Mozumder, Aloke K.; Mahmud, Shohel; Das, Prodip K.

2017-06-01

Natural convection heat transfer and fluid flow inside enclosures filled with fluids, such as air, water or oil, have been extensively analysed for thermal enhancement and optimisation due to their applications in many engineering problems, including solar collectors, electronic cooling, lubrication technologies, food processing and nuclear reactors. In comparison, little effort has been given to the problem of natural convection inside enclosures filled with nanofluids, while the addition of nanoparticles into a fluid base to alter thermal properties can be a feasible solution for many heat transfer problems. In this study, the problem of natural convection heat transfer and fluid flow inside a wavy enclosure filled with Al2O3-water nanofluid is investigated numerically using ANSYS-FLUENT. The effects of surface waviness and aspect ratio of the wavy enclosure on the heat transfer and fluid flow are analysed for various concentrations of Al2O3 nanoparticles in water. Flow fields and temperature fields are investigated and heat transfer rate is examined for different values of Rayleigh number. Results show that heat transfer within the enclosure can be enhanced by increasing surface waviness, aspect ratio or nanoparticles volume fraction. Changes in surface waviness have little effect on the heat transfer rate at low Rayleigh numbers, but when Ra ≥ 105 heat transfer increases with the increase of surface waviness from zero to higher values. Increasing the aspect ratio causes an increase in heat transfer rate, as the Rayleigh number increases the effect of changing aspect ratio is more apparent with the greatest heat transfer enhancement seen at higher Rayleigh numbers. Nanoparticles volume fraction has a little effect on the average Nusselt number at lower Rayleigh numbers when Ra ≥ 105 average Nusselt number increases with the increase of volume fraction. These findings provide insight into the heat transfer effects of using Al2O3-water nanofluid as a heat

Effects of Wavenumber and Chirality on the Axial Compressive Behavior of Wavy Carbon Nanotubes: A Molecular Mechanics Study

Directory of Open Access Journals (Sweden)

Masaki Kawachi

2014-01-01

Full Text Available The effects of wavenumber and chirality on the axial compressive behavior and properties of wavy carbon nanotubes (CNTs with multiple Stone-Wales defects are investigated using molecular mechanics simulations with the adaptive intermolecular reactive empirical bond-order potential. The wavy CNTs are assumed to be point-symmetric with respect to their axial centers. It is found that the wavy CNT models, respectively, exhibit a buckling point and long wavelength buckling mode regardless of the wavenumbers and chiralities examined. It is also found that the wavy CNTs have nearly the same buckling stresses as their pristine straight counterparts.

Analytical and numerical techniques for predicting the interfacial stresses of wavy carbon nanotube/polymer composites

NARCIS (Netherlands)

Yazdchi, K.; Salehi, M.; Shokrieh, M.M.

2009-01-01

By introducing a new simplified 3D representative volume element for wavy carbon nanotubes, an analytical model is developed to study the stress transfer in single-walled carbon nanotube-reinforced polymer composites. Based on the pull-out modeling technique, the effects of waviness, aspect ratio,

[The peculiar morphological features of the imprints of straight and wavy head hair dirtied with blood].

Science.gov (United States)

Leonova, E N; Nagornov, M N; Prokhorenko, A S

2018-01-01

The objective of the present study was to elucidate the specific morphological features of the imprints of blood-soaked straight and wavy head hair. The contact imprints of straight and wavy head hair dirtied with blood were obtained experimentally. The imprints of straight hair were shown to exhibit the elements in the form of the rectilinear and bow-shaped slightly bent stripes. The imprints of wavy hair were shaped as the arches, waves, circles, and a large number of various small elements, such as dashes and commas.

The influence of double nested layer waviness on compression strength of carbon fiber composite materials

International Nuclear Information System (INIS)

Khan, Z.M.

1997-01-01

As advanced composite materials having superior physical and mechanical properties are being developed, optimization of their production processes in eagerly being sought. One of the most common defect in production of structural composites is layer waviness. Layer waviness is more pronounced in thick section flat and cylindrical laminates that are extensively used in missile casings, submersibles and space platforms. Layer waviness undulates the entire layers of a multidirectional laminate in through-the-thickness direction leading to gross deterioration of its compression strength. This research investigates the influence of multiple layer waviness in a double nest formation on the compression strength of a composite laminate. Different wave fractions of wave 0 degree centigrade layer fabricated in IM/85510-7 carbon - epoxy composite laminate on a steel mold using single step fabrication procedure. The laminate was cured on a heated press according to specific curing cycle. Static compression testing was performed using NASA short block compression fixture on an MTS servo Hydraulic machine. The purpose of these tests was to determine the effects of multiple layer wave regions on the compression strength of composite laminate. The experimental and analytical results revealed that up to about 35% fraction of wave 0 degree layer exceeded 35%. This analysis indicated that the percentage of 0 degree wavy layer may be used to estimate the reduction in compression strength of a composite laminate under restricted conditions. (author)

Analytical and numerical solution of three-dimensional channel flow in presence of a sinusoidal fluid injection and a chemical reaction

Directory of Open Access Journals (Sweden)

Sahin Ahmed

2015-06-01

Full Text Available Modeling of three-dimensional channel flow in a chemically-reacting fluid between two long vertical parallel flat plates in the presence of a transverse magnetic field is presented. The stationary plate is subjected to a transverse sinusoidal injection velocity distribution while the uniformly moving plate is subjected to a constant suction and slip boundary conditions. Due to this type of injection velocity, the flow becomes three dimensional. Comparisons with previously published work are performed and the results are found to be in excellent agreement. An increase in the permeability/magnetic parameter is found to escalate the velocity near the plate in motion. Growing Reynolds number or magnetic parameter enhances the x-component and reduces the z-component of the skin-friction at the wall at rest. The acquired knowledge in our study can be used by designers to control MHD flow as suitable for certain applications which include laminar magneto-aerodynamics, materials processing and MHD propulsion thermo-fluid dynamics.

Wing in Ground Effect over a Wavy Surface

Directory of Open Access Journals (Sweden)

Valentin Adrian Jean BUTOESCU

2018-06-01

Full Text Available A vortex method has been used to investigate the effect of a wavy ground on the aerodynamic forces acting on a wing that flies in its proximity. The air is considered inviscid and incompressible. The problem is obviously unsteady, and the solutions were found numerically.

Effectiveness-NTU analyses in a double tube heat exchanger equipped with wavy strip considering various angles

International Nuclear Information System (INIS)

Pourahmad, Saman; Pesteei, S.M.

2016-01-01

Highlights: • Double tube heat exchanger equipped with wavy strip turbulators was studied. • The effects of wavy strip angles on the effectiveness were investigated. • Variation of the effectiveness with hot and cold water flow rate was presented. • The effectiveness increases with the decrease of wavy strip angle. • The friction factor increases with the decrease of wavy strip angle. - Abstract: In the present study, effectiveness-NTU analyses in a double tube heat exchanger equipped with wavy strip considering various angles were experimentally studied. Moreover, variation of the effectiveness with hot water Reynolds numbers for different cold water flow rates were presented. These turbulators with different angles of 45°, 60°, 90°, 120° and 150° were made of galvanized plates with thickness of 1 mm and were installed in the inner tube of heat exchanger. The experiments were carried out at Reynolds numbers of 3000–13,500 at turbulent flow regime. Throughout the experiments, hot and cold water flowed through the inner pipe and the space between the pipes (annulus), respectively. It was tried to keep the inlet hot and cold water temperatures at constant values. Effectiveness-NTU analyses were made for the conditions with and without wavy strips including their different angles and compared to each other. Results showed the considerable effect of turbulators on effectiveness (ε) and number of heat transfer units (NTU) of double tube heat exchanger. In addition, some empirical correlations expressing the results were also developed based on curve fitting.

Influences of the wavy surface inserted in the middle of a circular tube heat exchanger on thermal performance

Energy Technology Data Exchange (ETDEWEB)

Jedsadaratanancai, Withada [King Mongkut' s Institute of Technology Ladkrabang, Bangkok (Thailand); Boonloi, Amnart [King Mongkut' s University of Technology North Bangkok, Bangkok (Thailand)

2015-09-15

Numerical investigations on flow topology, heat transfer behavior and performance evaluation in a circular tube inserted with various configurations of wavy surfaces, Inclined wavy surface (IWS), V-downstream wavy surface (VDWS), V-Upstream wavy surface (VUWS) are presented. The effects of the flow attack angles; 20 .deg., 30 .deg., 45.deg. and 60.deg. are studied for the Reynolds numbers, Re = 100-2000. The numerical results are compared with the smooth circular tube with no wavy surface and the previous works. It is found that the IWS, VDWS and VUWS can produce longitudinal vortex flow and impinging jet of the fluid flow like inclined baffle, V-downstream baffle and V-Upstream baffle, respectively, but give lower friction loss. The flow phenomena created by the wavy surfaces help to augment the heat transfer rate and thermal performance in the test tube. In the range studied, the order of enhancement for heat transfer rate is around 1.40-3.75, 1.60-6.25 and 1.30-5.80 times higher than the smooth tube for IWS, VDWS and VUWS, respectively. Moreover, the maximum thermal performance, presented in terms of the Thermal enhancement factor (TEF), is found to be about 1.60, 2.40 and 2.10, respectively, for IWS, VUWS and VDWS.

Flaser and wavy bedding in ephemeral streams: a modern and an ancient example

Science.gov (United States)

Martin, A. J.

2000-10-01

Flaser and wavy bedding are sedimentary structures characterized by alternating rippled sand and mud layers. These structures often are considered to form mostly in tidally influenced environments; published examples from fluvial environments are rare. Flaser and wavy bedding were found in two ephemeral stream deposits: the Jurassic Kayenta Formation and the modern wash in Seven Mile Canyon, both located in southeastern Utah, USA. These examples demonstrate that flaser bedding can form and be preserved in ephemeral streams.

Slug-flow dynamics with phase change heat transfer in compact heat exchangers with oblique wavy walls

Science.gov (United States)

Morimoto, Kenichi; Kinoshita, Hidenori; Matsushita, Ryo; Suzuki, Yuji

2017-11-01

With abundance of low-temperature geothermal energy source, small-scale binary-cycle power generation system has gained renewed attention. Although heat exchangers play a dominant role in thermal efficiency and the system size, the optimum design strategy has not been established due to complex flow phenomena and the lack of versatile heat transfer models. In the present study, the concept of oblique wavy walls, with which high j/f factor is achieved by strong secondary flows in single-phase system, is extended to two-phase exchangers. The present analyses are based on evaporation model coupled to a VOF technique, and a train of isolated bubbles is generated under the controlled inlet quality. R245fa is adopted as a low boiling-point working media, and two types of channels are considered with a hydraulic diameter of 4 mm: (i) a straight circular pipe and (ii) a duct with oblique wavy walls. The focus is on slug-flow dynamics with evaporation under small capillary but moderate Weber numbers, where the inertial effect as well as the surface tension is of significance. A possible direction of the change in thermo-physical properties is explored by assuming varied thermal conductivity. Effects of the vortical motions on evaporative heat transfer are highlighted. This work has been supported by the New Energy and Industrial Technology Development Organization (NEDO), Japan.

Direct Numerical Simulation of Oscillatory Flow Over a Wavy, Rough, and Permeable Bottom

Science.gov (United States)

Mazzuoli, Marco; Blondeaux, Paolo; Simeonov, Julian; Calantoni, Joseph

2018-03-01

The results of a direct numerical simulation of oscillatory flow over a wavy bottom composed of different layers of spherical particles are described. The amplitude of wavy bottom is much smaller in scale than typical bed forms such as sand ripples. The spherical particles are packed in such a way to reproduce a bottom profile observed during an experiment conducted in a laboratory flow tunnel with well-sorted coarse sand. The amplitude and period of the external forcing flow as well as the size of the particles are set equal to the experimental values and the computed velocity field is compared with the measured velocity profiles. The direct numerical simulation allows for the evaluation of quantities, which are difficult to measure in a laboratory experiment (e.g., vorticity, seepage flow velocity, and hydrodynamic force acting on sediment particles). In particular, attention is focused on the coherent vortex structures generated by the vorticity shed by both the spherical particles and the bottom waviness. Results show that the wavy bottom triggers transition to turbulence. Moreover, the forces acting on the spherical particles are computed to investigate the mechanisms through which they are possibly mobilized by the oscillatory flow. It was found that forces capable of mobilizing surface particles are strongly correlated with the particle position above the mean bed elevation and the passage of coherent vortices above them.

A novel zebrafish mutant with wavy-notochord: an effective biological index for monitoring the copper pollution of water from natural resources.

Science.gov (United States)

Chen, Yau-Hung; Lin, Ji-Sheng

2011-02-01

We identified a novel zebrafish mutant that has wavy-notochord phenotypes, such as severely twisted notochord and posterior malformations, but has normal melanocytes. Histological evidences showed that proliferating vacuolar cells extended their growth to the muscle region, and consequently caused the wavy-notochord phenotypes. Interestingly, those malformations can be greatly reversed by exposure with copper, suggesting that copper plays an important role on wavy-notochord phenotypes. In addition, after long-term copper exposure, the surviving larvae derived from wavy-notochord mutants displayed bone malformations, such as twisted axial skeleton and osteophyte. These phenotypic changes and molecular evidences of wavy-notochord mutants are highly similar to those embryos whose lysyl oxidases activities have been inactivated. Taken together, we propose that (i) the putative mutated genes of this wavy-notochord mutant might be highly associated with the lysyl oxidase genes in zebrafish; and (ii) this fish model is an effective tool for monitoring copper pollution of water from natural resources. Copyright © 2009 Wiley Periodicals, Inc.

Control of cavity acoustics by surface waviness in landing configurations

CSIR Research Space (South Africa)

Dala, L

2014-08-01

Full Text Available ): 2321-3051 INTERNATIONAL JOURNAL OF RESEARCH IN AERONAUTICAL AND MECHANICAL ENGINEERING Control of Cavity Acoustics by Surface Waviness In Landing Configurations Laurent Dala CSIR, DPSS/Aeronautics Systems, Pretoria 0001, South Africa...

Single ICCII Sinusoidal Oscillators Employing Grounded Capacitors

Directory of Open Access Journals (Sweden)

J. W. Horng

2011-09-01

Full Text Available Two inverting second-generation current conveyors (ICCII based sinusoidal oscillators are presented. The first sinusoidal oscillator is composed of one ICCII, two grounded capacitors and two resistors. The oscillation condition and oscillation frequency can be orthogonally controllable. The second sinusoidal oscillator is composed of one ICCII, two grounded capacitors and three resistors. The oscillation condition and oscillation frequency can be independently controllable through different resistors.

Post-modelling of images from a laser-induced wavy boiling front

Energy Technology Data Exchange (ETDEWEB)

Matti, R.S., E-mail: ramiz.matti@ltu.se [Luleå University of Technology, Department of Engineering Sciences and Mathematics, SE-971 87 Luleå (Sweden); University of Mosul, College of Engineering, Department of Mechanical Engineering, Mosul (Iraq); Kaplan, A.F.H. [Luleå University of Technology, Department of Engineering Sciences and Mathematics, SE-971 87 Luleå (Sweden)

2015-12-01

Highlights: • New method: post-modelling of high speed images from a laser-induced front. • From the images a wavy cavity and its absorption distribution is calculated. • Histograms enable additional statistical analysis and understanding. • Despite the complex topology the absorptivity is bound to 35–43%. • The new method visualizes valuable complementary information. - Abstract: Processes like laser keyhole welding, remote fusion laser cutting or laser drilling are governed by a highly dynamic wavy boiling front that was recently recorded by ultra-high speed imaging. A new approach has now been established by post-modelling of the high speed images. Based on the image greyscale and on a cavity model the three-dimensional front topology is reconstructed. As a second step the Fresnel absorptivity modulation across the wavy front is calculated, combined with the local projection of the laser beam. Frequency polygons enable additional analysis of the statistical variations of the properties across the front. Trends like shadow formation and time dependency can be studied, locally and for the whole front. Despite strong topology modulation in space and time, for lasers with 1 μm wavelength and steel the absorptivity is bounded to a narrow range of 35–43%, owing to its Fresnel characteristics.

"Artificial micro organs"--a microfluidic device for dielectrophoretic assembly of liver sinusoids.

Science.gov (United States)

Schütte, Julia; Hagmeyer, Britta; Holzner, Felix; Kubon, Massimo; Werner, Simon; Freudigmann, Christian; Benz, Karin; Böttger, Jan; Gebhardt, Rolf; Becker, Holger; Stelzle, Martin

2011-06-01

In order to study possible toxic side effects of potential drug compounds in vitro a reliable test system is needed. Predicting liver toxicity presents a major challenge of particular importance as liver cells grown in a cell culture suffer from a rapid loss of their liver specific functions. Therefore we are developing a new microfluidic test system for liver toxicity. This test system is based on an organ-like liver 3D co-culture of hepatocytes and endothelial cells. We devised a microfluidic chip featuring cell culture chambers with integrated electrodes for the assembly of liver sinusoids by dielectrophoresis. Fluid channels enable an organ-like perfusion with culture media and test compounds. Different chamber designs were studied and optimized with regard to dielectrophoretic force distribution, hydrodynamic flow profile, and cell trapping rate using numeric simulations. Based on simulation results a microchip was injection-moulded from COP. This chip allowed the assembly of viable hepatocytes and endothelial cells in a sinusoid-like fashion.

Flow over a traveling wavy foil with a passively flapping flat plate

Science.gov (United States)

Liu, Nansheng; Peng, Yan; Liang, Youwen; Lu, Xiyun

2012-05-01

Flow over a traveling wavy foil with a passively flapping flat plate has been investigated using a multiblock lattice Boltzmann equation and the immersed boundary method. The foil undergoes prescribed undulations in the lateral direction and the rigid flat plate has passive motion determined by the fluid structure interaction. This simplified model is used to study the effect of the fish caudal fin and its flexibility on the locomotion of swimming animals. The flexibility of the caudal fin is modeled by a torsion spring acting about the pivot at the conjuncture of the wavy foil and the flat plate. The study reveals that the passively oscillating flat plate contributes half of the propulsive force. The flexibility, represented by the nondimensional natural frequency F, plays a very important role in the movement and propulsive force generation of the whole body. When the plate is too flexible, the drag force is observed. As the flat plate becomes more rigid, the propulsive force that is generated when the undulation is confined to last part of the wavy foil becomes larger. The steady movement occurs at F=5. These results are consistent with the observations of some swimming animals in nature.

Noise upon the Sinusoids

DEFF Research Database (Denmark)

Jensen, Karl Kristoffer

2005-01-01

Sinusoids are used for making harmonic and other sounds. In order to having life in the sounds and adding a wide variety of noises, irregularities are inserted in the frequency and amplitudes. A simple and intuitive noise model is presented, consisting of a low-pass filtered noise, and having...... control for strength and bandwidth. The noise is added on the frequency and amplitudes of the sinusoids, and the resulting irregularity’s (jitter and shimmer) bandwidth is derived. This, together with an overview of investigation methods of the jitter and shimmer results in an analysis of the necessary...

Numerical Study of Wavy Film Flow on Vertical Plate Using Different Turbulent Models

Energy Technology Data Exchange (ETDEWEB)

Min, June Kee [Pusan National University, Busan (Korea, Republic of); Park, Il Seouk [Kyungpook National University, Daegu (Korea, Republic of)

2014-05-15

Film flows applied to shell-and-tube heat exchangers in various industrial fields have been studied for a long time. One boundary of the film flow interfaces with a fixed wall, and the other boundary interfaces with a gaseous region. Thus, the flows become so unstable that wavy behaviors are generated on free surfaces as the film Reynolds number increases. First, high-amplitude solitary waves are detected in a low Reynolds number laminar region; then, the waves transit to a low-amplitude, high frequency ripple in a turbulent region. Film thickness is the most significant factor governing heat transfer. Since the wave accompanied in the film flow results in temporal and spatial variations in film thickness, it can be of importance for numerically predicting the film's wavy behavior. In this study, various turbulent models are applied for predicting low-amplitude ripple flows in turbulent regions. The results are compared with existing experimental results, and finally, the applied turbulent models are appraised in from the viewpoint of wavy behaviors.

Numerical Study of Wavy Film Flow on Vertical Plate Using Different Turbulent Models

International Nuclear Information System (INIS)

Min, June Kee; Park, Il Seouk

2014-01-01

Film flows applied to shell-and-tube heat exchangers in various industrial fields have been studied for a long time. One boundary of the film flow interfaces with a fixed wall, and the other boundary interfaces with a gaseous region. Thus, the flows become so unstable that wavy behaviors are generated on free surfaces as the film Reynolds number increases. First, high-amplitude solitary waves are detected in a low Reynolds number laminar region; then, the waves transit to a low-amplitude, high frequency ripple in a turbulent region. Film thickness is the most significant factor governing heat transfer. Since the wave accompanied in the film flow results in temporal and spatial variations in film thickness, it can be of importance for numerically predicting the film's wavy behavior. In this study, various turbulent models are applied for predicting low-amplitude ripple flows in turbulent regions. The results are compared with existing experimental results, and finally, the applied turbulent models are appraised in from the viewpoint of wavy behaviors

The Effect of Thermal Radiation on Entropy Generation Due to Micro-Polar Fluid Flow Along a Wavy Surface

Directory of Open Access Journals (Sweden)

Kuei-Hao Chang

2011-09-01

Full Text Available In this study, the effect of thermal radiation on micro-polar fluid flow over a wavy surface is studied. The optically thick limit approximation for the radiation flux is assumed. Prandtl’s transposition theorem is used to stretch the ordinary coordinate system in certain directions. The wavy surface can be transferred into a calculable plane coordinate system. The governing equations of micro-polar fluid along a wavy surface are derived from the complete Navier-Stokes equations. A simple transformation is proposed to transform the governing equations into boundary layer equations so they can be solved numerically by the cubic spline collocation method. A modified form for the entropy generation equation is derived. Effects of thermal radiation on the temperature and the vortex viscosity parameter and the effects of the wavy surface on the velocity are all included in the modified entropy generation equation.

Amplitude Modulated Sinusoidal Signal Decomposition for Audio Coding

DEFF Research Database (Denmark)

Christensen, M. G.; Jacobson, A.; Andersen, S. V.

2006-01-01

In this paper, we present a decomposition for sinusoidal coding of audio, based on an amplitude modulation of sinusoids via a linear combination of arbitrary basis vectors. The proposed method, which incorporates a perceptual distortion measure, is based on a relaxation of a nonlinear least......-squares minimization. Rate-distortion curves and listening tests show that, compared to a constant-amplitude sinusoidal coder, the proposed decomposition offers perceptually significant improvements in critical transient signals....

The response of skin friction, wall heat transfer and pressure drop to wall waviness in the presence of buoyancy

Directory of Open Access Journals (Sweden)

C. N. B. Rao

1982-01-01

Full Text Available Laminar natural convection flow and heat transfer of a viscous incompressible fluid confined between two long vertical wavy walls has been analysed taking the fluid properties constant and variable. In particular, attention is restricted to estimate the effects of viscous dissipation and wall waviness on the flow and heat transfer characteristics. Use has been made of a linearization technique to simplify the governing equations and of Galerkin's method in the solution. The solutions obtained for the velocity and the temperature-fields hold good for all values of the Grashof number and wave number of the wavy walls.

Hierarchical macroscopic fibrillar adhesives: in situ study of buckling and adhesion mechanisms on wavy substrates.

Science.gov (United States)

Bauer, Christina T; Kroner, Elmar; Fleck, Norman A; Arzt, Eduard

2015-10-23

Nature uses hierarchical fibrillar structures to mediate temporary adhesion to arbitrary substrates. Such structures provide high compliance such that the flat fibril tips can be better positioned with respect to asperities of a wavy rough substrate. We investigated the buckling and adhesion of hierarchically structured adhesives in contact with flat smooth, flat rough and wavy rough substrates. A macroscopic model for the structural adhesive was fabricated by molding polydimethylsiloxane into pillars of diameter in the range of 0.3-4.8 mm, with up to three different hierarchy levels. Both flat-ended and mushroom-shaped hierarchical samples buckled at preloads one quarter that of the single level structures. We explain this behavior by a change in the buckling mode; buckling leads to a loss of contact and diminishes adhesion. Our results indicate that hierarchical structures can have a strong influence on the degree of adhesion on both flat and wavy substrates. Strategies are discussed that achieve highly compliant substrates which adhere to rough substrates.

Modeling Solar Energetic Particle Transport near a Wavy Heliospheric Current Sheet

Science.gov (United States)

Battarbee, Markus; Dalla, Silvia; Marsh, Mike S.

2018-02-01

Understanding the transport of solar energetic particles (SEPs) from acceleration sites at the Sun into interplanetary space and to the Earth is an important question for forecasting space weather. The interplanetary magnetic field (IMF), with two distinct polarities and a complex structure, governs energetic particle transport and drifts. We analyze for the first time the effect of a wavy heliospheric current sheet (HCS) on the propagation of SEPs. We inject protons close to the Sun and propagate them by integrating fully 3D trajectories within the inner heliosphere in the presence of weak scattering. We model the HCS position using fits based on neutral lines of magnetic field source surface maps (SSMs). We map 1 au proton crossings, which show efficient transport in longitude via HCS, depending on the location of the injection region with respect to the HCS. For HCS tilt angles around 30°–40°, we find significant qualitative differences between A+ and A‑ configurations of the IMF, with stronger fluences along the HCS in the former case but with a distribution of particles across a wider range of longitudes and latitudes in the latter. We show how a wavy current sheet leads to longitudinally periodic enhancements in particle fluence. We show that for an A+ IMF configuration, a wavy HCS allows for more proton deceleration than a flat HCS. We find that A‑ IMF configurations result in larger average fluences than A+ IMF configurations, due to a radial drift component at the current sheet.

Wavy Architecture Thin-Film Transistor for Ultrahigh Resolution Flexible Displays

KAUST Repository

Hanna, Amir Nabil; Kutbee, Arwa Talal; Subedi, Ram Chandra; Ooi, Boon S.; Hussain, Muhammad Mustafa

2017-01-01

A novel wavy-shaped thin-film-transistor (TFT) architecture, capable of achieving 70% higher drive current per unit chip area when compared with planar conventional TFT architectures, is reported for flexible display application. The transistor, due to its atypical architecture, does not alter the turn-on voltage or the OFF current values, leading to higher performance without compromising static power consumption. The concept behind this architecture is expanding the transistor's width vertically through grooved trenches in a structural layer deposited on a flexible substrate. Operation of zinc oxide (ZnO)-based TFTs is shown down to a bending radius of 5 mm with no degradation in the electrical performance or cracks in the gate stack. Finally, flexible low-power LEDs driven by the respective currents of the novel wavy, and conventional coplanar architectures are demonstrated, where the novel architecture is able to drive the LED at 2 × the output power, 3 versus 1.5 mW, which demonstrates the potential use for ultrahigh resolution displays in an area efficient manner.

Wavy Architecture Thin-Film Transistor for Ultrahigh Resolution Flexible Displays

KAUST Repository

Hanna, Amir Nabil

2017-11-13

A novel wavy-shaped thin-film-transistor (TFT) architecture, capable of achieving 70% higher drive current per unit chip area when compared with planar conventional TFT architectures, is reported for flexible display application. The transistor, due to its atypical architecture, does not alter the turn-on voltage or the OFF current values, leading to higher performance without compromising static power consumption. The concept behind this architecture is expanding the transistor\\'s width vertically through grooved trenches in a structural layer deposited on a flexible substrate. Operation of zinc oxide (ZnO)-based TFTs is shown down to a bending radius of 5 mm with no degradation in the electrical performance or cracks in the gate stack. Finally, flexible low-power LEDs driven by the respective currents of the novel wavy, and conventional coplanar architectures are demonstrated, where the novel architecture is able to drive the LED at 2 × the output power, 3 versus 1.5 mW, which demonstrates the potential use for ultrahigh resolution displays in an area efficient manner.

Compressed Domain Packet Loss Concealment of Sinusoidally Coded Speech

DEFF Research Database (Denmark)

Rødbro, Christoffer A.; Christensen, Mads Græsbøll; Andersen, Søren Vang

2003-01-01

We consider the problem of packet loss concealment for voice over IP (VoIP). The speech signal is compressed at the transmitter using a sinusoidal coding scheme working at 8 kbit/s. At the receiver, packet loss concealment is carried out working directly on the quantized sinusoidal parameters......, based on time-scaling of the packets surrounding the missing ones. Subjective listening tests show promising results indicating the potential of sinusoidal speech coding for VoIP....

Sensorless optimal sinusoidal brushless direct current for hard disk drives

Science.gov (United States)

Soh, C. S.; Bi, C.

2009-04-01

Initiated by the availability of digital signal processors and emergence of new applications, market demands for permanent magnet synchronous motors have been surging. As its back-emf is sinusoidal, the drive current should also be sinusoidal for reducing the torque ripple. However, in applications like hard disk drives, brushless direct current (BLDC) drive is adopted instead of sinusoidal drive for simplification. The adoption, however, comes at the expense of increased harmonics, losses, torque pulsations, and acoustics. In this paper, we propose a sensorless optimal sinusoidal BLDC drive. First and foremost, the derivation for an optimal sinusoidal drive is presented, and a power angle control scheme is proposed to achieve an optimal sinusoidal BLDC. The scheme maintains linear relationship between the motor speed and drive voltage. In an attempt to execute the sensorless drive, an innovative power angle measurement scheme is devised, which takes advantage of the freewheeling diodes and measures the power angle through the detection of diode voltage drops. The objectives as laid out will be presented and discussed in this paper, supported by derivations, simulations, and experimental results. The proposed scheme is straightforward, brings about the benefits of sensorless sinusoidal drive, negates the need for current sensors by utilizing the freewheeling diodes, and does not incur additional cost.

Sinusoidal Analysis-Synthesis of Audio Using Perceptual Criteria

Science.gov (United States)

Painter, Ted; Spanias, Andreas

2003-12-01

This paper presents a new method for the selection of sinusoidal components for use in compact representations of narrowband audio. The method consists of ranking and selecting the most perceptually relevant sinusoids. The idea behind the method is to maximize the matching between the auditory excitation pattern associated with the original signal and the corresponding auditory excitation pattern associated with the modeled signal that is being represented by a small set of sinusoidal parameters. The proposed component-selection methodology is shown to outperform the maximum signal-to-mask ratio selection strategy in terms of subjective quality.

Deep-etched sinusoidal polarizing beam splitter grating.

Science.gov (United States)

Feng, Jijun; Zhou, Changhe; Cao, Hongchao; Lv, Peng

2010-04-01

A sinusoidal-shaped fused-silica grating as a highly efficient polarizing beam splitter (PBS) is investigated based on the simplified modal method. The grating structure depends mainly on the ratio of groove depth to grating period and the ratio of incident wavelength to grating period. These ratios can be used as a guideline for the grating design at different wavelengths. A sinusoidal-groove PBS grating is designed at a wavelength of 1310 nm under Littrow mounting, and the transmitted TM and TE polarized waves are mainly diffracted into the zeroth order and the -1st order, respectively. The grating profile is optimized by using rigorous coupled-wave analysis. The designed PBS grating is highly efficient (>95.98%) over the O-band wavelength range (1260-1360 nm) for both TE and TM polarizations. The sinusoidal grating can exhibit higher diffraction efficiency, larger extinction ratio, and less reflection loss than the rectangular-groove PBS grating. By applying wet etching technology on the rectangular grating, which was manufactured by holographic recording and inductively coupled plasma etching technology, the sinusoidal grating can be approximately fabricated. Experimental results are in agreement with theoretical values.

EXPERIMENTAL EVALUATION OF WEDM MACHINED SURFACE WAVINESS

Directory of Open Access Journals (Sweden)

Katerina Mouralova

2016-10-01

Full Text Available Wire Electrical Discharge Machining (WEDM an unconventional machining technology which has become indispensable in many industries. The typical morphology of a surface machined using the electrical discharge technology is characterized with a large number of craters caused by electro-spark discharges produced during the machining process. The study deals with an evaluation of the machine parameter setting on the profile parameters of surface waviness on samples made of two metal materials Al 99.5 and Ti-6Al-4V. Attention was also paid to an evaluation of the surface morphology using 3D colour filtered and non-filtered images.

Finite element analysis of BWR fuel channel buckling during a seismic event

International Nuclear Information System (INIS)

Kinoshita, Mika; Iwamoto, Yuji; Ledford, Kevin; Cantonwine, Paul

2014-01-01

This paper documents the predicted response of three BWR fuel channel designs in bending using a typical moment profile for GNF fuel designs. The bending performance of the fuel channel is predicted using ANSYS, a finite element modeling tool. Specifically, linear and non-linear buckling analyses were performed to determine the onset of elastic buckling, which causes a wavy structure on the compression face in bending that might also increase channel – control blade friction, and to determine to onset of channel collapse, which causes permanent deformation and would inhibit control rod insertion. The three channel designs considered in this paper are the 0.080 inch uniform channel, the 0.100 inch uniform channel and the 0.120 inch uniform channel at the beginning of fuel life (BOL) and at the end of fuel life (EOL). (author)

Variable Dimension Trellis-Coded Quantization of Sinusoidal Parameters

DEFF Research Database (Denmark)

Larsen, Morten Holm; Christensen, Mads G.; Jensen, Søren Holdt

2008-01-01

In this letter, we propose joint quantization of the parameters of a set of sinusoids based on the theory of trellis-coded quantization. A particular advantage of this approach is that it allows for joint quantization of a variable number of sinusoids, which is particularly relevant in variable...

Estimating Aquifer Properties Using Sinusoidal Pumping Tests

Science.gov (United States)

Rasmussen, T. C.; Haborak, K. G.; Young, M. H.

2001-12-01

We develop the theoretical and applied framework for using sinusoidal pumping tests to estimate aquifer properties for confined, leaky, and partially penetrating conditions. The framework 1) derives analytical solutions for three boundary conditions suitable for many practical applications, 2) validates the analytical solutions against a finite element model, 3) establishes a protocol for conducting sinusoidal pumping tests, and 4) estimates aquifer hydraulic parameters based on the analytical solutions. The analytical solutions to sinusoidal stimuli in radial coordinates are derived for boundary value problems that are analogous to the Theis (1935) confined aquifer solution, the Hantush and Jacob (1955) leaky aquifer solution, and the Hantush (1964) partially penetrated confined aquifer solution. The analytical solutions compare favorably to a finite-element solution of a simulated flow domain, except in the region immediately adjacent to the pumping well where the implicit assumption of zero borehole radius is violated. The procedure is demonstrated in one unconfined and two confined aquifer units near the General Separations Area at the Savannah River Site, a federal nuclear facility located in South Carolina. Aquifer hydraulic parameters estimated using this framework provide independent confirmation of parameters obtained from conventional aquifer tests. The sinusoidal approach also resulted in the elimination of investigation-derived wastes.

Encryption in Chaotic Systems with Sinusoidal Excitations

Directory of Open Access Journals (Sweden)

G. Obregón-Pulido

2014-01-01

Full Text Available In this contribution an encryption method using a chaotic oscillator, excited by “n” sinusoidal signals, is presented. The chaotic oscillator is excited by a sum of “n” sinusoidal signals and a message. The objective is to encrypt such a message using the chaotic behavior and transmit it, and, as the chaotic system is perturbed by the sinusoidal signal, the transmission security could be increased due to the effect of such a perturbation. The procedure is based on the regulation theory and consider that the receiver knows the frequencies of the perturbing signal, with this considerations the algorithm estimates the excitation in such a way that the receiver can cancel out the perturbation and all the undesirable dynamics in order to produce only the message. In this way we consider that the security level is increased.

Bottomside sinusoidal irregularities in the equatorial F region

Science.gov (United States)

Valladares, C. E.; Hanson, W. B.; Mcclure, J. P.; Cragin, B. L.

1983-01-01

By using the Ogo 6 satellite, McClure and Hanson (1973) have discovered sinusoidal irregularities in the equatorial F region ion number density. In the present investigation, a description is provided of the properties of a distinct category of sinusoidal irregularities found in equatorial data from the AE-C and AE-E satellites. The observed scale sizes vary from about 300 m to 3 km in the direction perpendicular to B, overlapping with and extending the range observed by using Ogo 6. Attention is given to low and high resolution data, a comparison with Huancayo ionograms, the confinement of 'bottomside sinusoidal' (BSS) irregularities essentially to the bottomside of the F layer, spectral characteristics, and BSS, scintillation, and ionosonde observations.

Airflow measurements at a wavy air-water interface using PIV and LIF

Science.gov (United States)

Buckley, Marc P.; Veron, Fabrice

2017-11-01

Physical phenomena at an air-water interface are of interest in a variety of flows with both industrial and natural/environmental applications. In this paper, we present novel experimental techniques incorporating a multi-camera multi-laser instrumentation in a combined particle image velocimetry and laser-induced fluorescence system. The system yields accurate surface detection thus enabling velocity measurements to be performed very close to the interface. In the application presented here, we show results from a laboratory study of the turbulent airflow over wind driven surface waves. Accurate detection of the wavy air-water interface further yields a curvilinear coordinate system that grants practical and easy implementation of ensemble and phase averaging routines. In turn, these averaging techniques allow for the separation of mean, surface wave coherent, and turbulent velocity fields. In this paper, we describe the instrumentation and techniques and show several data products obtained on the air-side of a wavy air-water interface.

Numerical Study of Natural Convection within a Wavy Enclosure Using Meshfree Approach: Effect of Corner Heating

Directory of Open Access Journals (Sweden)

Sonam Singh

2014-01-01

Full Text Available This paper presents a numerical study of natural convection within a wavy enclosure heated via corner heating. The considered enclosure is a square enclosure with left wavy side wall. The vertical wavy wall of the enclosure and both of the corner heaters are maintained at constant temperature, Tc and Th, respectively, with Th>Tc while the remaining horizontal, bottom, top and side walls are insulated. A penalty element-free Galerkin approach with reduced gauss integration scheme for penalty terms is used to solve momentum and energy equations over the complex domain with wide range of parameters, namely, Rayleigh number (Ra, Prandtl number (Pr, and range of heaters in the x- and y-direction. Numerical results are represented in terms of isotherms, streamlines, and Nusselt number. It is observed that the rate of heat transfer depends to a great extent on the Rayleigh number, Prandtl number, length of the corner heaters and the shape of the heat transfer surface. The consistent performance of the adopted numerical procedure is verified by comparison of the results obtained through the present meshless technique with those existing in the literature.

Absorptivity modulation on wavy molten steel surfaces: The influence of laser wavelength and angle of incidence

International Nuclear Information System (INIS)

Kaplan, A. F. H.

2012-01-01

The modulation of the angle-dependent Fresnel absorptivity across wavy molten steel surfaces during laser materials processing, like drilling, cutting, or welding, has been calculated. The absorptivity is strongly altered by the grazing angle of incidence of the laser beam on the processing front. Owing to its specific Brewster-peak characteristics, the 10.64 μm wavelength CO 2 -laser shows an opposite trend with respect to roughness and angle-of-incidence compared to lasers in the wavelength range of 532-1070 nm. Plateaus or rings of Brewster-peak absorptivity can lead to hot spots on a wavy surface, often in close proximity to cold spots caused by shadow domains.

Adaptive Feedforward Cancellation of Sinusoidal Disturbances in Superconducting RF Cavities

CERN Document Server

Kandil, T H; Hartung, W; Khalil, H; Popielarski, J; Vincent, J; York, R C

2004-01-01

A control method, known as adaptive feedforward cancellation (AFC) is applied to damp sinusoidal disturbances due to microphonics in superconducting RF (SRF) cavities. AFC provides a method for damping internal, and external sinusoidal disturbances with known frequencies. It is preferred over other schemes because it uses rudimentary information about the frequency response at the disturbance frequencies, without the necessity of knowing an analytic model (transfer function) of the system. It estimates the magnitude and phase of the sinusoidal disturbance inputs and generates a control signal to cancel their effect. AFC, along with a frequency estimation process, is shown to be very successful in the cancellation of sinusoidal signals from different sources. The results of this research may significantly reduce the power requirements and increase the stability for lightly loaded continuous-wave SRF systems.

Sinusoidal oscillators and waveform generators using modern electronic circuit building blocks

CERN Document Server

Senani, Raj; Singh, V K; Sharma, R K

2016-01-01

This book serves as a single-source reference to sinusoidal oscillators and waveform generators, using classical as well as a variety of modern electronic circuit building blocks. It provides a state-of-the-art review of a large variety of sinusoidal oscillators and waveform generators and includes a catalogue of over 600 configurations of oscillators and waveform generators, describing their relevant design details and salient performance features/limitations. The authors discuss a number of interesting, open research problems and include a comprehensive collection of over 1500 references on oscillators and non-sinusoidal waveform generators/relaxation oscillators. Offers readers a single-source reference to everything connected to sinusoidal oscillators and waveform generators, using classical as well as modern electronic circuit building blocks; Provides a state-of-the-art review of a large variety of sinusoidal oscillators and waveform generators; Includes a catalog of over 600 configurations of oscillato...

Natural convection heat transfer from a horizontal wavy surface in a porous enclosure

International Nuclear Information System (INIS)

Murthy, P.V.S.N.; Kumar, B.V.R.; Singh, P.

1997-01-01

The effect of surface undulations on the natural convection heat transfer from an isothermal surface in a Darcian fluid-saturated porous enclosure has been numerically analyzed using the finite element method on a graded nonuniform mesh system. The flow-driving Rayleigh number Ra together with the geometrical parameters of wave amplitude a, wave phase φ, and the number of waves N considered in the horizontal dimension of the cavity are found to influence the flow and heat transfer process in the enclosure. For Ra around 50 and above, the phenomenon of flow separation and reattachment is noticed on the walls of the enclosure. A periodic shift in the reattachment point from the bottom wall to the adjacent walls in the clockwise direction, leading to the manifestation of cycles of unicellular and bicellular clockwise and counterclockwise flows, is observed, with the phase varying between 0 degree and 350 degree. The counterflow in the secondary circulation zone is intensified with the increase in the value of Ra. The counterflow on the wavy wall hinders the heat transfer into the system. An increase in either wave amplitude or the number of waves considered per unit length decreases the global heat flux into the system. Only marginal changes in global heat flux are noticed with increasing Ra. On the whole, the comparison of global heat flux results in the wavy wall case with those of the horizontal flat wall case shows that, in a porous enclosure, the wavy wall reduces the heat transfer into the system

Numerical Simulation of Turbulent Convective Flow Over Wavy Terrain

OpenAIRE

Dörnbrack, A.; Schumann, U.

1993-01-01

By means of a large-eddy simulation, the convective boundary layer is investigated for flows over wavy terrain. The lower surface varies sinusoidalty in the downstream direction while remaining constant in the other. Several cases are considered with amplitude 6 up to 0.15H and wavelength A of H to 8H, where H is the mean fluid-layer height. At the lower surface, the vertical heat flux is prescribed to be constant and the momentum flux is determined locally from the Monin-Obukhov relationship...

Wavy strings: Black or bright?

International Nuclear Information System (INIS)

Kaloper, N.; Myers, R.C.; Roussel, H.

1997-01-01

Recent developments in string theory have brought forth considerable interest in time-dependent hair on extended objects. This novel new hair is typically characterized by a wave profile along the horizon and angular momentum quantum numbers l,m in the transverse space. In this work, we present an extensive treatment of such oscillating black objects, focusing on their geometric properties. We first give a theorem of purely geometric nature, stating that such wavy hair cannot be detected by any scalar invariant built out of the curvature and/or matter fields. However, we show that the tidal forces detected by an infalling observer diverge at the open-quotes horizonclose quotes of a black string superposed with a vibration in any mode with l≥1. The same argument applied to longitudinal (l=0) waves detects only finite leading-order tidal forces. We also provide an example with a manifestly smooth metric, proving that at least a certain class of these longitudinal waves have regular horizons. copyright 1997 The American Physical Society

CNNs for sinusoidal signal recognition in hearing rehabilitation

Science.gov (United States)

Carnimeo, Leonarda; Giaquinto, Antonio

2003-04-01

In this paper, a contribution is given to provide a tool to the recognition of sinusoidal signals with a particular reference to the field of pediatric hearing rehabilitation. To this purpose, a synthesis technique previously developed by the authors' is used to design a Cellular Neural Network for an Associative Memory able to compare submitted discrete-time sinusoidal signals with memorized ones. A robustness analysis of the synthesized associative memory is also developed both for noisy inputs and for parameter variations. Simulation results are then reported to illustrate the performances of the designed network.

Cosmology and the Sinusoidal Potential

Science.gov (United States)

Bartlett, David F.

2006-06-01

The nature of dark matter (and dark energy) remains a mystery. An alternative is being explored by several scientists: changing Newton's (and Einstein's) field equations. The sinusoidal potential is the latest attempt[1]. Here the gravitational law is alternately attractive and repulsive:φ = -GM cos(kor)/r, where λo=2π/ko = 1/20 of the distance from the sun to the center of the Milky Way. The proposal accommodates several structural features of the Milky Way including, paradoxically, its spiral shape and flat rotation curve. The sinusoidal potential's unique feature is strong galactic tidal forces (dg/dr). These may explain why the new planetoid Sedna is securely between the Kuiper Belt and the Oort cloud and why distant comets are more influenced by galactic tides that are in the r, rather than the z-direction.At this meeting I discuss the consequences of the sinusoidal potential for cosmology. Here the alternation of attraction and repulsion gives (i) an open universe, and (ii) gravitational lensing which is usually weak, but occasionally very strong. An open universe is one that, asymptotically, has a size R which varies directly as time t. The open universe conflicts both with the old Einstein-deSitter model (R α t2/3} and the new accelerating one. The evidence for an accelerating universe decisively rejects the Einstein-deSitter model. The rejection of an open (or empty) universe is less secure. This rejection is influenced by the different ways the groups studying the brightness of supernovae use the HST. Surprising additional inputs include neutrino masses, the equivalence principle, LSB galaxies, and "over-luminous" Sn1a. I thank Mostafa Jon Dadras and Patrick Motl for early help and John Cumalat for continual support. [1] D.F. Bartlett, "Analogies between electricity and gravity", Metrologia 41, S115-S124 (2004).

Converter for Measurement of non-sinusoidal current peak value

DEFF Research Database (Denmark)

Butvin, P.; Nielsen, Otto V; Brauer, Peter

1997-01-01

A linear-response toroid with core wound of rapidly quenched soft magnetic metallic ribbon and fitted with two windings is used to enable correct measurement of mean peak value of non-sinusoidal and not noise-free alternating current.......A linear-response toroid with core wound of rapidly quenched soft magnetic metallic ribbon and fitted with two windings is used to enable correct measurement of mean peak value of non-sinusoidal and not noise-free alternating current....

Effect of Wavy Trailing Edge on 100meter Flatback Wind Turbine Blade

International Nuclear Information System (INIS)

Yang, SJ; Baeder, J D

2016-01-01

The flatback trailing edge design for modern 100meter wind turbine blade has been developed and proposed to make wind turbine blade to be slender and lighter. On the other hand, it will increase aerodynamic drag; consequently the increased drag diminishes turbine power generation. Thus, an aerodynamic drag reducing technique should be accompanied with the flatback trailing edge in order to prevent loss of turbine power generation. In this work, a drag mitigation design, span-wise wavy trailing edge blade, has been applied to a modern 100meter blade. The span-wise trailing edge acts as a vortex generator, and breaks up the strong span-wise coherent trailing edge vortex structure at the flatback airfoil trailing edge which is a major source of large drag. Three-dimensional unsteady Computational Fluid Dynamics (CFD) simulations have been performed for real scale wind turbine blade geometries. Delayed Detached Eddy Simulation (DDES) with the modified laminar-turbulent transition model has been applied to obtain accurate flow field predictions. Graphical Processor Unit (GPU)-accelerated computation has been conducted to reduce computational costs of the real scale wind turbine blade simulations. To verify the structural reliability of the wavy modification of the blade a simple Eigen buckling analysis has been performed in the current study. (paper)

Broad bandwidth vibration energy harvester based on thermally stable wavy fluorinated ethylene propylene electret films with negative charges

Science.gov (United States)

Zhang, Xiaoqing; Sessler, Gerhard M.; Ma, Xingchen; Xue, Yuan; Wu, Liming

2018-06-01

Wavy fluorinated ethylene propylene (FEP) electret films with negative charges were prepared by a patterning method followed by a corona charging process. The thermal stability of these films was characterized by the surface potential decay with annealing time at elevated temperatures. The results show that thermally stable electret films can be made by corona charging followed by pre-aging treatment. Vibration energy harvesters having a very simple sandwich structure, consisting of a central wavy FEP electret film and two outside metal plates, were designed and their performance, including the resonance frequency, output power, half power bandwidth, and device stability, was investigated. These harvesters show a broad bandwidth as well as high output power. Their performance can be further improved by using a wavy-shaped counter electrode. For an energy harvester with an area of 4 cm2 and a seismic mass of 80 g, the output power referred to 1 g (g is the gravity of the earth), the resonance frequency, and the 3 dB bandwidth are 1.85 mW, 90 Hz, and 24 Hz, respectively. The output power is sufficient to power some electronic devices. Such devices may be embedded in shoe soles, carpets or seat cushions where the flexibility is required and large force is available.

Computationally Efficient Amplitude Modulated Sinusoidal Audio Coding using Frequency-Domain Linear Prediction

DEFF Research Database (Denmark)

Christensen, M. G.; Jensen, Søren Holdt

2006-01-01

A method for amplitude modulated sinusoidal audio coding is presented that has low complexity and low delay. This is based on a subband processing system, where, in each subband, the signal is modeled as an amplitude modulated sum of sinusoids. The envelopes are estimated using frequency......-domain linear prediction and the prediction coefficients are quantized. As a proof of concept, we evaluate different configurations in a subjective listening test, and this shows that the proposed method offers significant improvements in sinusoidal coding. Furthermore, the properties of the frequency...

On Angular Sampling Methods for 3-D Spatial Channel Models

DEFF Research Database (Denmark)

Fan, Wei; Jämsä, Tommi; Nielsen, Jesper Ødum

2015-01-01

This paper discusses generating three dimensional (3D) spatial channel models with emphasis on the angular sampling methods. Three angular sampling methods, i.e. modified uniform power sampling, modified uniform angular sampling, and random pairing methods are proposed and investigated in detail....... The random pairing method, which uses only twenty sinusoids in the ray-based model for generating the channels, presents good results if the spatial channel cluster is with a small elevation angle spread. For spatial clusters with large elevation angle spreads, however, the random pairing method would fail...... and the other two methods should be considered....

Full-Band Quasi-Harmonic Analysis and Synthesis of Musical Instrument Sounds with Adaptive Sinusoids

Directory of Open Access Journals (Sweden)

Marcelo Caetano

2016-05-01

Full Text Available Sinusoids are widely used to represent the oscillatory modes of musical instrument sounds in both analysis and synthesis. However, musical instrument sounds feature transients and instrumental noise that are poorly modeled with quasi-stationary sinusoids, requiring spectral decomposition and further dedicated modeling. In this work, we propose a full-band representation that fits sinusoids across the entire spectrum. We use the extended adaptive Quasi-Harmonic Model (eaQHM to iteratively estimate amplitude- and frequency-modulated (AM–FM sinusoids able to capture challenging features such as sharp attacks, transients, and instrumental noise. We use the signal-to-reconstruction-error ratio (SRER as the objective measure for the analysis and synthesis of 89 musical instrument sounds from different instrumental families. We compare against quasi-stationary sinusoids and exponentially damped sinusoids. First, we show that the SRER increases with adaptation in eaQHM. Then, we show that full-band modeling with eaQHM captures partials at the higher frequency end of the spectrum that are neglected by spectral decomposition. Finally, we demonstrate that a frame size equal to three periods of the fundamental frequency results in the highest SRER with AM–FM sinusoids from eaQHM. A listening test confirmed that the musical instrument sounds resynthesized from full-band analysis with eaQHM are virtually perceptually indistinguishable from the original recordings.

Inverse modelling and pulsating torque minimization of salient pole non-sinusoidal synchronous machines

Energy Technology Data Exchange (ETDEWEB)

Ait-gougam, Y.; Ibtiouen, R.; Touhami, O. [Laboratoire de Recherche en Electrotechnique, Ecole Nationale Polytechnique, BP 182, El-Harrach 16200 (Algeria); Louis, J.-P.; Gabsi, M. [Systemes et Applications des Technologies de l' Information et de l' Energie (SATIE), CNRS UMR 8029, Ecole Normale Superieure de Cachan, 61 Avenue du President Wilson, 94235 Cachan Cedex (France)

2008-01-15

Sinusoidal motor's mathematical models are usually obtained using classical d-q transformation in the case of salient pole synchronous motors having sinusoidal field distribution. In this paper, a new inverse modelling for synchronous motors is presented. This modelling is derived from the properties of constant torque curves in the Concordia's reference frame. It takes into account the non-sinusoidal field distribution; EMF, self and mutual inductances having non-sinusoidal variations with respect to the angular rotor position. Both copper losses and torque ripples are minimized by adapted currents waveforms calculated from this model. Experimental evaluation was carried out on a DSP-controlled PMSM drive platform. Test results obtained demonstrate the effectiveness of the proposed method in reducing torque ripple. (author)

Effect of the Wavy permeable Interface on Double Diffusive Natural Convection in a Partially Porous Cavity

Directory of Open Access Journals (Sweden)

R Mehdaoui

2016-09-01

Full Text Available Two-dimensional, double diffusion, natural convection in a partially porous cavity satured with a binary fluid is investigated numerically. Multiple motions are driven by the external temperature and concentration differences imposed across vertical walls. The wavy interface between fluid and porous layer is horizontal. The equations which describe the fluid flow and heat and mass transfer are described by the Navier-Stokes equations (fluid region, Darcy-Brinkman equation (porous region and energy and mass equations. The finite element method was applied to solve the governing equations. The fluid flow and heat and mass transfer has been investigated for different values of the amplitude and the wave number of the interface and the buoyancy ratio. The results obtained in the form of isotherms, stream lines, isoconcentrations and the Nusselt and Sherwood numbers; show that the wavy interface has a significant effect on the flow and heat and mass transfer.

Electronically Tunable Quadrature Sinusoidal Oscillator with Equal Output Amplitudes during Frequency Tuning Process

Directory of Open Access Journals (Sweden)

Den Satipar

2017-01-01

Full Text Available A new configuration of voltage-mode quadrature sinusoidal oscillator is proposed. The proposed oscillator employs two voltage differencing current conveyors (VDCCs, two resistors, and two grounded capacitors. In this design, the use of multiple/dual output terminal active building block is not required. The tuning of frequency of oscillation (FO can be done electronically by adjusting the bias current of active device without affecting condition of oscillation (CO. The electronic tuning can be done by controlling the bias current using a digital circuit. The amplitude of two sinusoidal outputs is equal when the frequency of oscillation is tuned. This makes the sinusoidal output voltages meet good total harmonic distortions (THD. Moreover, the proposed circuit can provide the sinusoidal output current with high impedance which is connected to external load or to another circuit without the use of buffer device. To confirm that the oscillator can generate the quadrature sinusoidal output signal, the experimental results using VDCC constructed from commercially available ICs are also included. The experimental results agree well with theoretical anticipation.

Efficiency enhancement of a self-propelled pitching profile using non-sinusoidal trajectories

Science.gov (United States)

Mekadem, M.; Chihani, E.; Oualli, H.; Hanchi, S.; Bouabdallah, A.; Gad-El-Hak, M.

2017-11-01

A symmetrical profile is subjected to non-sinusoidal pitching motion. The airfoil has a chord length c = 0.006 m and a semi-circular leading edge with a diameter of D = 0.001 m. The extrados and intrados are two straight lines that intersect at a tapered trailing edge, and the pitching pivot point is positioned at the leading edge. The pitching frequency is in the range of 1 based upon the maximum profile thickness D varies in the range of 35 <= Re <= 210 , which matches insect's Reynolds numbers. The foil movement is executed using the dynamic mesh technique and a user defined function (UDF). The adopted mesh has 70,445 nodes with 5,1960 quadrilateral cells. The results are in good agreement with prior experiments, and, compared to sinusoidal oscillations, show that non-sinusoidal flapping trajectories lead to advancing velocity increase of 550%. Additionally, if improved propulsive efficiency is sought, non-sinusoidal flapping lead to better thrust.

Simultaneous measurements of thickness and temperature profile in a wavy liquid film falling freely on a heating wall

International Nuclear Information System (INIS)

Lyu, T.; Mudawar, I.

1990-01-01

This paper reports on a technique for measuring the thickness of liquid films that was developed and tested. The feasibility of this technique was demonstrated in stagnant liquid films as well as in liquid jets. A procedure for in-situ calibration of the thickness probe was developed, allowing the adaptation of the probe to measurements of wavy liquid films. The thickness probe was constructed from a platinum-rhodium wire that was stretched across the film. A constant DC current was supplied through the probe wire, and film thickness was determined from variations in the probe voltage drop resulting from the large differences in the electrical resistances of the wetted and unwetted segments of the wire. Unlike electrical admittance thickness probes, the new probe did not require dissolving an electrolyte in the liquid, making the new probe well suited to studies involving sensible heating of a film of pure dielectric liquid that is in direct contact with a current- carrying wall. Also presented is a composite probe that facilitated simultaneous measurements of temperature profile across a wavy liquid film and film thickness. Experimental results demonstrate a strong influence of waviness on liquid temperature in a film of deionized water falling freely on the outside wall of a vertical, electrically heated tube for film Reynolds numbers smaller than 10,000

Enhancement of tensile ductility and stretch formability of AZ31 magnesium alloy sheet processed by cross-wavy bending

International Nuclear Information System (INIS)

Huo, Qinghuan; Yang, Xuyue; Sun, Huan; Li, Bin; Qin, Jia; Wang, Jun; Ma, Jijun

2013-01-01

Highlights: •The AZ31 Mg alloy sheet is deformed to 4 passes at 673 K by cross-wavy bending. •A fine-grained microstructure and a weak and random texture are achieved. •Different softening mechanisms significantly affect the microstructure evolution. •The tensile ductility and stretch formability enhance dramatically. -- Abstract: The microstructure and texture evolution in the sheets of AZ31 magnesium alloy was studied by means of cross-wavy bending for 4 passes at 673 K. The bended samples were examined by optical microscopy and electron backscatter diffraction analysis. Finite element analysis suggested an inhomogeneous deformation at each pass. Following cross-wavy bending, a fine-grained microstructure with an average grain size of ∼8 μm and a weak and random basal texture were achieved. Accumulative effective strain was almost equal in the whole sheet at the end. Different work softening mechanisms significantly affected the evolution of the microstructure. Dynamic recovery played an important role during the first three bending passes whereas, in contrast, dynamic recrystallization dominated the evident grain refinement during the last pass. The tensile ductility and stretch formability of the 4-pass sheet at room temperature were distinctly enhanced compared to the initial sheet (1.55 and 2 times larger, respectively). These prominent increases were mainly attributed to texture randomizing rather than texture weakening alone

3D palmprint and hand imaging system based on full-field composite color sinusoidal fringe projection technique.

Science.gov (United States)

Zhang, Zonghua; Huang, Shujun; Xu, Yongjia; Chen, Chao; Zhao, Yan; Gao, Nan; Xiao, Yanjun

2013-09-01

Palmprint and hand shape, as two kinds of important biometric characteristics, have been widely studied and applied to human identity recognition. The existing research is based mainly on 2D images, which lose the third-dimensional information. The biological features extracted from 2D images are distorted by pressure and rolling, so the subsequent feature matching and recognition are inaccurate. This paper presents a method to acquire accurate 3D shapes of palmprint and hand by projecting full-field composite color sinusoidal fringe patterns and the corresponding color texture information. A 3D imaging system is designed to capture and process the full-field composite color fringe patterns on hand surface. Composite color fringe patterns having the optimum three fringe numbers are generated by software and projected onto the surface of human hand by a digital light processing projector. From another viewpoint, a color CCD camera captures the deformed fringe patterns and saves them for postprocessing. After compensating for the cross talk and chromatic aberration between color channels, three fringe patterns are extracted from three color channels of a captured composite color image. Wrapped phase information can be calculated from the sinusoidal fringe patterns with high precision. At the same time, the absolute phase of each pixel is determined by the optimum three-fringe selection method. After building up the relationship between absolute phase map and 3D shape data, the 3D palmprint and hand are obtained. Color texture information can be directly captured or demodulated from the captured composite fringe pattern images. Experimental results show that the proposed method and system can yield accurate 3D shape and color texture information of the palmprint and hand shape.

A Perceptual Model for Sinusoidal Audio Coding Based on Spectral Integration

Directory of Open Access Journals (Sweden)

Jensen Søren Holdt

2005-01-01

Full Text Available Psychoacoustical models have been used extensively within audio coding applications over the past decades. Recently, parametric coding techniques have been applied to general audio and this has created the need for a psychoacoustical model that is specifically suited for sinusoidal modelling of audio signals. In this paper, we present a new perceptual model that predicts masked thresholds for sinusoidal distortions. The model relies on signal detection theory and incorporates more recent insights about spectral and temporal integration in auditory masking. As a consequence, the model is able to predict the distortion detectability. In fact, the distortion detectability defines a (perceptually relevant norm on the underlying signal space which is beneficial for optimisation algorithms such as rate-distortion optimisation or linear predictive coding. We evaluate the merits of the model by combining it with a sinusoidal extraction method and compare the results with those obtained with the ISO MPEG-1 Layer I-II recommended model. Listening tests show a clear preference for the new model. More specifically, the model presented here leads to a reduction of more than 20% in terms of number of sinusoids needed to represent signals at a given quality level.

Unidirectional Motion of Vehicle on Sinusoidal Path

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 17; Issue 4. Unidirectional Motion of Vehicle on Sinusoidal Path: Can it Cause Illusory Forward and Backward Motion? Anuj Bhatnagar. Classroom Volume 17 Issue 4 April 2012 pp 387-392 ...

Crashworthiness Analysis and Evaluation of Fuselage Section with Sub-floor Composite Sinusoidal Specimens

Directory of Open Access Journals (Sweden)

H.L. Mou

Full Text Available Abstract Crashworthiness is one of the main concerns in civil aviation safety particularly with regard to the increasing ratio of carbon fiber reinforced plastic (CFRP in aircraft primary structures. In order to generate dates for model validations, the mechanical properties of T700/3234 were obtained by material performance tests, and energy-absorbing results were gained by quasi-static crushing tests of composite sinusoidal specimens. The correctness of composite material model and single-layer finite element model of composite sinusoidal specimens were verified based on the simulation results and test results that were in good agreement. A typical civil aircraft fuselage section with composite sinusoidal specimens under cargo floor was suggested. The crashworthiness of finite element model of fuselage section was assessed by simulating the vertical drop test subjected to 7 m/s impact velocity, and the influences of different thickness of sub-floor composite sinusoidal specimens on crashworthiness of fuselage section were also analyzed. The simulation results show that the established finite element model can accurately simulate the crushing process of composite sinusoidal specimens; the failure process of fuselage section is more stable, and the safety of occupants can be effectively improved because of the smaller peak accelerations that was limited to human tolerance, a critical thickness of sub-floor composite sinusoidal specimens can restrict the magnitude of acceleration peaks, which has certain reference values for enhancing crashworthiness capabilities of fuselage section and improving the survivability of passengers.

Walking strategies of visually impaired people on trapezoidal- and sinusoidal-section tactile groundsurface indicators.

Science.gov (United States)

Ranavolo, A; Conte, C; Iavicoli, S; Serrao, M; Silvetti, A; Sandrini, G; Pierelli, F; Draicchio, F

2011-03-01

The visual system in walking serves to perceive feedback or feed-forward signals. Therefore, visually impaired persons (VIP) have biased motor control mechanisms. The use of leading indicators (LIs) and long canes helps to improve their walking efficiency. The aims of this study were to compare the walking efficiency of VIP on trapezoidal- and sinusoidal-section LIs using an optoelectronic motion analysis system. VIP displayed a significantly longer stance phase, a shorter swing phase and shorter step and stride lengths when they walked on the sinusoidal LI than when they walked on the trapezoidal LI. Compared with the trapezoidal LI, VIP walking on the sinusoidal LI displayed significantly lower joint ranges of motion. The centre of mass lateral displacement was wider for VIP walking on the sinusoidal LI than on the trapezoidal LI. Some significant differences were also found in sighted persons walking on both LIs. In conclusion, the trapezoidal shape enabled visually impaired subjects to walk more efficiently, whereas the sinusoidal shape caused dynamic balance problems. STATEMENT OF RELEVANCE: These findings suggest that VIP can walk more efficiently, with a lower risk of falls, on trapezoidal-section than on sinusoidal-section LIs. These results should be considered when choosing the most appropriate ground tactile surface indicators for widespread use.

The sinusoidal lining cells in "normal" human liver. A scanning electron microscopic investigation

DEFF Research Database (Denmark)

Horn, T; Henriksen, Jens Henrik Sahl; Christoffersen, P

1986-01-01

The scanning electron microscopic was used to study the fenestrations of human liver sinusoids. Thirteen biopsies, where light microscopy and transmission electron microscopy revealed normal sinusoidal architecture, were investigated. The number of fenestrae was calculated in acinar zone 3...

Investigation of Calibrating Force Transducer Using Sinusoidal Force

International Nuclear Information System (INIS)

Zhang Li; Wang Yu; Zhang Lizhe

2010-01-01

Sinusoidal force calibration method was studied several years before at Physikalisch-Technische Bundesanstalt (PTB). A similar dynamic force calibration system is developed at Changcheng Institute of Metrology and Measurement (CIMM). It uses electro-dynamic shakers to generate dynamic force in the range from 1 N to 20 kN, and heterodyne laser interferometers are used for acceleration measurement. The force transducer to be calibrated is mounted on the shaker, and a mass block is screwed on the top of force transducer, the sinusoidal forces realized by accelerated load masses are traceable to acceleration and mass according to the force definition. The methods of determining Spatial-dependent acceleration on mass block and measuring the end mass of force transducer in dynamic force calibration are discussed in this paper.

ERG voltage-gated K+ channels regulate excitability and discharge dynamics of the medial vestibular nucleus neurones.

Science.gov (United States)

Pessia, Mauro; Servettini, Ilenio; Panichi, Roberto; Guasti, Leonardo; Grassi, Silvarosa; Arcangeli, Annarosa; Wanke, Enzo; Pettorossi, Vito Enrico

2008-10-15

The discharge properties of the medial vestibular nucleus neurones (MVNn) critically depend on the activity of several ion channel types. In this study we show, immunohistochemically, that the voltage-gated K(+) channels ERG1A, ERG1B, ERG2 and ERG3 are highly expressed within the vestibular nuclei of P10 and P60 mice. The role played by these channels in the spike-generating mechanisms of the MVNn and in temporal information processing was investigated electrophysiologically from mouse brain slices, in vitro, by analysing the spontaneous discharge and the response to square-, ramp- and sinusoid-like intracellular DC current injections in extracellular and whole-cell patch-clamp studies. We show that more than half of the recorded MVNn were responsive to ERG channel block (WAY-123,398, E4031), displaying an increase in spontaneous activity and discharge irregularity. The response to step and ramp current injection was also modified by ERG block showing a reduction of first spike latency, enhancement of discharge rate and reduction of the slow spike-frequency adaptation process. ERG channels influence the interspike slope without affecting the spike shape. Moreover, in response to sinusoid-like current, ERG channel block caused frequency-dependent gain enhancement and phase-lead shift. Taken together, the data demonstrate that ERG channels control the excitability of MVNn, their discharge regularity and probably their resonance properties.

A Novel Simulator of Nonstationary Random MIMO Channels in Rayleigh Fading Scenarios

Directory of Open Access Journals (Sweden)

Qiuming Zhu

2016-01-01

Full Text Available For simulations of nonstationary multiple-input multiple-output (MIMO Rayleigh fading channels in time-variant scattering environments, a novel channel simulator is proposed based on the superposition of chirp signals. This new method has the advantages of low complexity and implementation simplicity as the sum of sinusoids (SOS method. In order to reproduce realistic time varying statistics for dynamic channels, an efficient parameter computation method is also proposed for updating the frequency parameters of employed chirp signals. Simulation results indicate that the proposed simulator is effective in generating nonstationary MIMO channels with close approximation of the time-variant statistical characteristics in accordance with the expected theoretical counterparts.

Some New Results on the Estimation of Sinusoids in Noise

DEFF Research Database (Denmark)

Nielsen, Jesper Kjær

2012-01-01

This thesis is concerned with the problem of estimating sinusoidal parameters from noisy observations. This field of research is applicable to solving problems in a large number of areas such as music and speech processing, electrocardiography, seismology, radar and sonar processing, astronomy....... Third, an efficient algorithm for performing inference and interpolation in a dynamic sinusoidal model is proposed. This method is applied to packet-loss concealment, and listening tests indicate that the proposed algorithm can be used for this purpose. Fourth, the Capon filtering method for amplitude...

An Adaptive Filter for the Removal of Drifting Sinusoidal Noise Without a Reference.

Science.gov (United States)

Kelly, John W; Siewiorek, Daniel P; Smailagic, Asim; Wang, Wei

2016-01-01

This paper presents a method for filtering sinusoidal noise with a variable bandwidth filter that is capable of tracking a sinusoid's drifting frequency. The method, which is based on the adaptive noise canceling (ANC) technique, will be referred to here as the adaptive sinusoid canceler (ASC). The ASC eliminates sinusoidal contamination by tracking its frequency and achieving a narrower bandwidth than typical notch filters. The detected frequency is used to digitally generate an internal reference instead of relying on an external one as ANC filters typically do. The filter's bandwidth adjusts to achieve faster and more accurate convergence. In this paper, the focus of the discussion and the data is physiological signals, specifically electrocorticographic (ECoG) neural data contaminated with power line noise, but the presented technique could be applicable to other recordings as well. On simulated data, the ASC was able to reliably track the noise's frequency, properly adjust its bandwidth, and outperform comparative methods including standard notch filters and an adaptive line enhancer. These results were reinforced by visual results obtained from real ECoG data. The ASC showed that it could be an effective method for increasing signal to noise ratio in the presence of drifting sinusoidal noise, which is of significant interest for biomedical applications.

Influence of sinusoidal flow on the thermal and hydraulic performance of microchannel heat sink

International Nuclear Information System (INIS)

Om, N I; Gunnasegaran, P; Rajasegaran, S

2013-01-01

In this paper, the effect of sinusoidal flow on the thermal and hydraulic performance of microchannel heat sink (MCHS) is numerically investigated. This investigation covers Reynolds number in the range of 100 ≤ Re ≤ 1000 and pure water is used as a working fluid. The three-dimensional steady, laminar flow and heat transfer governing equations are solved using finite volume method (FVM). The water flow field and heat transfer performance inside the sinusoidal microchannels is simulated and the results are compared with the straight microchannels. The effect of using sinusoidal microchannels on temperature distribution, Nusselt number, friction factor and thermal resistance is presented in this paper. It is found that with same rectangular cross-section, sinusoidal microchannels have a better heat transfer performance compared to the straight microchannels.

Bioconvection nanofluid slip flow past a wavy surface with applications in nano-biofuel cells

OpenAIRE

Beg, OA; Uddin, MJ; Khan, WA; Qureshi, SR

2017-01-01

A theoretical study is presented to examine free convective boundary layer flow of water-based bio-nanofluid containing gyrotactic microorganisms past a wavy surface. Buongiorno’s nanofluid model with passively controlled boundary condition is applied to investigate the effects of the emerging parameters on the physical quantities namely, skin friction, Nusselt numbers and density number of motile microorganisms. The effects of the both hydrodynamic and thermal slips are also incorporated. Lo...

Regorafenib suppresses sinusoidal obstruction syndrome in rats.

Science.gov (United States)

Okuno, Masayuki; Hatano, Etsuro; Nakamura, Kojiro; Miyagawa-Hayashino, Aya; Kasai, Yosuke; Nishio, Takahiro; Seo, Satoru; Taura, Kojiro; Uemoto, Shinji

2015-02-01

Sinusoidal obstruction syndrome (SOS), a form of drug-induced liver injury related to oxaliplatin treatment, is associated with postoperative morbidity after hepatectomy. This study aimed to examine the impact of regorafenib, the first small-molecule kinase inhibitor to show efficacy against metastatic colorectal cancer, on a rat model of SOS. Rats with monocrotaline (MCT)-induced SOS were divided into two groups according to treatment with either regorafenib (6 mg/kg) or vehicle alone, which were administered at 12 and 36 h, respectively, before MCT administration. Histopathologic examination and serum biochemistry tests were performed 48 h after MCT administration. Sinusoidal endothelial cells were evaluated by immunohistochemistry and electron microscopy. To examine whether regorafenib preserved remnant liver function, a 30% hepatectomy was performed in each group. The rats in the vehicle group displayed typical SOS features, whereas these features were suppressed in the regorafenib group. The total SOS scores were significantly lower in the regorafenib group than in the vehicle group. Immunohistochemistry and electron microscopy showed that regorafenib had a protective effect on sinusoidal endothelial cells. The postoperative survival rate after 7 d was significantly better in the regorafenib group than that in the vehicle group (26.7% versus 6.7%, P Regorafenib reduced the phosphorylation of extracellular signal-regulated kinase, which induced matrix metalloproteinase-9 (MMP-9) activation and decreased the activity of MMP-9, one of the crucial mediators of SOS development. Regorafenib suppressed MCT-induced SOS, concomitant with attenuating extracellular signal-regulated kinase phosphorylation, and MMP-9 activation, suggesting that regorafenib may be a favorable agent for use in combination with oxaliplatin-based chemotherapy. Copyright © 2015 Elsevier Inc. All rights reserved.

An extended numerical calibration method for an electrochemical probe in thin wavy flow with large amplitude waves

Energy Technology Data Exchange (ETDEWEB)

Choi, Ki Yong; No, Hee Cheon [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

1999-12-31

The calibrating method for an electrochemical probe, neglecting the effect of the normal velocity on the mass transport, can cause large errors when applied to the measurement of wall shear rates in thin wavy flow with large amplitude waves. An extended calibrating method is developed to consider the contributions of the normal velocity. The inclusion of the turbulence-induced normal velocity term is found to have a negligible effect on the mass transfer coefficient. The contribution of the wave-induced normal velocity can be classified on the dimensionless parameter, V. If V is above a critical value of V, V{sub crit}, the effects of the wave-induced normal velocity become larger with an increase in V. While its effects negligible for inversely. The present inverse method can predict the unknown shear rate more accurately in thin wavy flow with large amplitude waves than the previous method. 18 refs., 8 figs. (Author)

An extended numerical calibration method for an electrochemical probe in thin wavy flow with large amplitude waves

Energy Technology Data Exchange (ETDEWEB)

Choi, Ki Yong; No, Hee Cheon [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

1998-12-31

The calibrating method for an electrochemical probe, neglecting the effect of the normal velocity on the mass transport, can cause large errors when applied to the measurement of wall shear rates in thin wavy flow with large amplitude waves. An extended calibrating method is developed to consider the contributions of the normal velocity. The inclusion of the turbulence-induced normal velocity term is found to have a negligible effect on the mass transfer coefficient. The contribution of the wave-induced normal velocity can be classified on the dimensionless parameter, V. If V is above a critical value of V, V{sub crit}, the effects of the wave-induced normal velocity become larger with an increase in V. While its effects negligible for inversely. The present inverse method can predict the unknown shear rate more accurately in thin wavy flow with large amplitude waves than the previous method. 18 refs., 8 figs. (Author)

Systematic periodicity in waviness of vertically aligned carbon nanotubes explained by helical buckling

Science.gov (United States)

Jahangiri, Mehdi

2017-09-01

A hypothesis is proposed in this work to account for the geometry of individual vertically aligned carbon nanotubes (VACNTs) that not only justifies the directionality of their growth, but also explains the origin of the waviness frequently reported for these nanotube forests. Such waviness has fundamental effects on the transport/conduction properties of VACNTs, either through or along them, regarding phenomena such as mass, stress, heat and electricity. Despite the general opinion about randomness of carbon nanotubes (CNTs) tortuosity, we demonstrate here that rules of helical buckling of tubular strings is applicable to VACNTs, based on which a regular 3D helical geometry is proposed for VACNTs, with a 2D sine wave shape side-profile. In this framework, gradual increase of the total free surface energy by growth of CNTs ensues their partial cohesion, driven by van der Waals interactions, to reduce the excess surface energy. On the other hand, their cohesion is accompanied by their deformation and loss of straightness, which in turn, translates to buildup of an elastic strain energy in the system. The balance of the two energies along with the spatial constraints on each CNT at its contact points with neighboring CNTs, is manifested in its helical buckling, that is systematically influenced by nanostructural characteristics of VACNTs, such as their diameter, wall thickness and inter-CNT spacing.

In-vitro study on haemodiluted blood flow in a sinusoidal microstenosis.

Science.gov (United States)

Kang, M J; Ji, H-S; Lee, S J

2010-01-01

In-vitro experiments were carried out to investigate the haemodynamic and haemorheological behaviours of haemodiluted blood flow through a microstenosis using a micro-particle image velocimetry (PIV) technique. The micro-PIV system employed in this study consisted of a two-head neodymium:yttrium-aluminium-garnet (Nd:YAG) laser, a cooled charge-coupled device camera, and a delay generator. To simulate blood flow in a stenosed vascular vessel, a polydimethylsiloxane (PDMS) microchannel with a sinusoidal throat of 80 per cent severity was employed. The width and depth of the microchannel were 100 microm and 50 microm, respectively. To compare the flow characteristics in the microstenosis, the same experiments were repeated in a straight microchannel under the same flow conditions. Using a syringe pump, human blood with 5 per cent haematocrit was supplied into the microstenosis channel. The flow characteristics and transport of blood cells through the microstenosis were investigated with various flowrates. The mean velocity fields were nearly symmetric with respect to the channel centreline. In the contraction section, the oncoming blood flow was accelerated rapidly, and the maximum velocity at the throat was almost 4.99 times faster than that of the straight microchannel without stenosis. In the diffusion section, the blood cells show rolling, deformation, twisting, and tumbling motion due to the flow-choking characteristics at the stenotic region. The results from this study will provide useful basic data for comparison with those obtained by clinical researchers.

MHD peristaltic motion of Johnson-Segalman fluid in a channel with compliant walls

International Nuclear Information System (INIS)

Hayat, T.; Javed, Maryiam; Asghar, S.

2008-01-01

A mathematical model for magnetohydrodynamic (MHD) flow of a Johnson-Segalman fluid in a channel with compliant walls is analyzed. The flow is engendered due to sinusoidal waves on the channel walls. A series solution is developed for the case in which the amplitude ratio is small. Our computations show that the mean axial velocity of a Johnson-Segalman fluid is smaller than that of a viscous fluid. The variations of various interesting dimensionless parameters are graphed and discussed

Model selection and comparison for independents sinusoids

DEFF Research Database (Denmark)

Nielsen, Jesper Kjær; Christensen, Mads Græsbøll; Jensen, Søren Holdt

2014-01-01

In the signal processing literature, many methods have been proposed for estimating the number of sinusoidal basis functions from a noisy data set. The most popular method is the asymptotic MAP criterion, which is sometimes also referred to as the BIC. In this paper, we extend and improve this me...

New Canonic Active RC Sinusoidal Oscillator Circuits Using Second-Generation Current Conveyors with Application as a Wide-Frequency Digitally Controlled Sinusoid Generator

Directory of Open Access Journals (Sweden)

Abhirup Lahiri

2011-01-01

Full Text Available This paper reports two new circuit topologies using second-generation current conveyors (CCIIs for realizing variable frequency sinusoidal oscillators with minimum passive components. The proposed topologies in this paper provide new realizations of resistance-controlled and capacitor-controlled variable frequency oscillators (VFOs using only four passive components. The first topology employs three CCIIs, while the second topology employs two CCIIs. The second topology provides an advantageous feature of frequency tuning through two grounded elements. Application of the proposed circuits as a wide-frequency range digitally controlled sinusoid generator is exhibited wherein the digital frequency control has been enabled by replacing both the capacitors by two identical variable binary capacitor banks tunable by means of the same binary code. SPICE simulations of the CMOS implementation of the oscillators using 0.35 μm TSMC CMOS technology parameters and bipolar implementation of the oscillators using process parameters for NR200N-2X (NPN and PR200N-2X (PNP of bipolar arrays ALA400-CBIC-R have validated their workability. One of the oscillators (with CMOS implementation is exemplified as a digitally controlled sinusoid generator with frequency generation from 25 kHz to 6.36 MHz, achieved by switching capacitors and with power consumption of 7 mW in the entire operating frequency range.

The effect of wheel eccentricity and run-out on grinding forces, waviness, wheel wear and chatter

OpenAIRE

O'DONNELL, GARRET; MURPHY, STUART

2011-01-01

PUBLISHED The effect of grinding-wheel eccentricity on grinding forces, wheel wear and final waviness height was studied. Eccentricity was evident in force oscillations and acceleration and audio measurements. A model was developed to predict final scallop-profile shape from grinding parameters and eccentricity. Recommendations are given on detecting eccentricity and determining when eccentricity is tolerable.

Light scattering by sinusoidal surfaces: illumination windows and harmonics in standards.

Science.gov (United States)

Marx, E; Lettieri, T R; Vorburger, T V

1995-03-01

Sinusoidal surfaces can be used as material standards to help calibrate instruments that measure the angular distribution of the intensity of light scattered by arbitrary surfaces, because the power in the diffraction peaks varies over several orders of magnitude. The calculated power in the higher-order diffraction peaks from sinusoidal surfaces expressed in terms of Bessel functions is much smaller than the values determined from angular distributions that are measured or computed from measured profiles, both of which are determined mainly by the harmonic contents of the profile. The finite size of the illuminated area, represented by an illumination window, gives rise to a background that is much larger than the calculated power in the higher-order peaks. For a rectangular window of a size equal to an even number of periods of the sinusoid, a computation of the power distribution produces minima at or near the location of the diffraction angles for higher-order diffraction angles.

Intravascular Immune Surveillance by CXCR6+ NKT Cells Patrolling Liver Sinusoids

Directory of Open Access Journals (Sweden)

Geissmann Frederic

2005-01-01

Full Text Available We examined the in vivo behavior of liver natural killer T cells (NKT cells by intravital fluorescence microscopic imaging of mice in which a green fluorescent protein cDNA was used to replace the gene encoding the chemokine receptor CXCR6. NKT cells, which account for most CXCR6+ cells in liver, were found to crawl within hepatic sinusoids at 10-20 µm/min and to stop upon T cell antigen receptor activation. CXCR6-deficient mice exhibited a selective and severe reduction of CD1d-reactive NKT cells in the liver and decreased susceptibility to T-cell-dependent hepatitis. CXCL16, the cell surface ligand for CXCR6, is expressed on sinusoidal endothelial cells, and CXCR6 deficiency resulted in reduced survival, but not in altered speed or pattern of patrolling of NKT cells. Thus, NKT cells patrol liver sinusoids to provide intravascular immune surveillance, and CXCR6 contributes to liver-based immune responses by regulating their abundance.

DISPLAY OF PIXEL LOSS AND REPLICATION IN REPROJECTING RASTER DATA FROM THE SINUSOIDAL PROJECTION

Science.gov (United States)

Recent studies show the sinusoidal projection to be a superior planar projection for representing global raster datasets. This study uses the sinusoidal projection as a basis for evaluating pixel loss and replication in eight other planar map projections. The percent of pixels ...

Polarization Patterns of Transmitted Celestial Light under Wavy Water Surfaces

Directory of Open Access Journals (Sweden)

Guanhua Zhou

2017-03-01

Full Text Available This paper presents a model to describe the polarization patterns of celestial light, which includes sunlight and skylight, when refracted by wavy water surfaces. The polarization patterns and intensity distribution of refracted light through the wave water surface were calculated. The model was validated by underwater experimental measurements. The experimental and theoretical values agree well qualitatively. This work provides a quantitative description of the repolarization and transmittance of celestial light transmitted through wave water surfaces. The effects of wind speed and incident sources on the underwater refraction polarization patterns are discussed. Scattering skylight dominates the polarization patterns while direct solar light is the dominant source of the intensity of the underwater light field. Wind speed has an influence on disturbing the patterns under water.

Dynamic Characteristics of Ventilatory and Gas Exchange during Sinusoidal Walking in Humans.

Directory of Open Access Journals (Sweden)

Yoshiyuki Fukuoka

Full Text Available Our present study investigated whether the ventilatory and gas exchange responses show different dynamics in response to sinusoidal change in cycle work rate or walking speed even if the metabolic demand was equivalent in both types of exercise. Locomotive parameters (stride length and step frequency, breath-by-breath ventilation (V̇E and gas exchange (CO2 output (V̇CO2 and O2 uptake (V̇O2 responses were measured in 10 healthy young participants. The speed of the treadmill was sinusoidally changed between 3 km·h-1 and 6 km·h-1 with various periods (from 10 to 1 min. The amplitude of locomotive parameters against sinusoidal variation showed a constant gain with a small phase shift, being independent of the oscillation periods. In marked contrast, when the periods of the speed oscillations were shortened, the amplitude of V̇E decreased sharply whereas the phase shift of V̇E increased. In comparing walking and cycling at the equivalent metabolic demand, the amplitude of V̇E during sinusoidal walking (SW was significantly greater than that during sinusoidal cycling (SC, and the phase shift became smaller. The steeper slope of linear regression for the V̇E amplitude ratio to V̇CO2 amplitude ratio was observed during SW than SC. These findings suggested that the greater amplitude and smaller phase shift of ventilatory dynamics were not equivalent between SW and SC even if the metabolic demand was equivalent between both exercises. Such phenomenon would be derived from central command in proportion to locomotor muscle recruitment (feedforward and muscle afferent feedback.

Unified design of sinusoidal-groove fused-silica grating.

Science.gov (United States)

Feng, Jijun; Zhou, Changhe; Cao, Hongchao; Lu, Peng

2010-10-20

A general design rule of deep-etched subwavelength sinusoidal-groove fused-silica grating as a highly efficient polarization-independent or polarization-selective device is studied based on the simplified modal method, which shows that the device structure depends little on the incident wavelength, but mainly on the ratio of groove depth to incident wavelength and the ratio of wavelength to grating period. These two ratios could be used as the design guidelines for wavelength-independent structure from deep ultraviolet to far infrared. The optimized grating profile with a different function as a polarizing beam splitter, a polarization-independent two-port beam splitter, or a polarization-independent grating with high efficiency of -1st order is obtained at a wavelength of 1064 nm, and verified by using the rigorous coupled-wave analysis. The performance of the sinusoidal grating is better than a conventional rectangular one, which could be useful for practical applications.

Riding the Ferris Wheel: A Sinusoidal Model

Science.gov (United States)

Mittag, Kathleen Cage; Taylor, Sharon E.

2011-01-01

When thinking of models for sinusoidal waves, examples such as tides of the ocean, daily temperatures for one year in your town, light and sound waves, and certain types of motion are used. Many textbooks [1, p. 222] also present a "Ferris wheel description problem" for students to work. This activity takes the Ferris wheel problem out of the…

Comparison between the water activation effects by pulsed and sinusoidal helium plasma jets

Science.gov (United States)

Xu, Han; Liu, Dingxin; Xia, Wenjie; Chen, Chen; Wang, Weitao; Liu, Zhijie; Wang, Xiaohua; Kong, Michael G.

2018-01-01

Comparisons between pulsed and sinusoidal plasma jets have been extensively reported for the discharge characteristics and gaseous reactive species, but rarely for the aqueous reactive species in water solutions treated by the two types of plasma jets. This motivates us to compare the concentrations of aqueous reactive species induced by a pulsed and a sinusoidal plasma jet, since it is widely reported that these aqueous reactive species play a crucial role in various plasma biomedical applications. Experimental results show that the aqueous H2O2, OH/O2-, and O2-/ONOO- induced by the pulsed plasma jet have higher concentrations, and the proportional difference increases with the discharge power. However, the emission intensities of OH(A) and O(3p5P) are higher for the sinusoidal plasma jet, which may be attributed to its higher gas temperature since more water vapor could participate in the plasma. In addition, the efficiency of bacterial inactivation induced by the pulsed plasma jet is higher than that for the sinusoidal plasma jet, in accordance with the concentration relation of aqueous reactive species for the two types of plasma jets.

Trans-sinusoidal maxillary distraction in three cleft patients.

NARCIS (Netherlands)

Wenghoefer, M.H.; Martini, M.; Nadjmi, N.; Schutyser, F.A.C.; Jagtman, A.K.; Bergé, S.J.

2006-01-01

The trans-sinusoidal maxillary distractor (TS-MD) was used to achieve maxillary advancement in three patients with repaired cleft lip and palate. After preoperative computer-aided planning of the distraction vectors, each TS-MD was bent on a stereolithographic model of the maxilla of the patient.

Molecular dynamics simulations of the effect of waviness and agglomeration of CNTs on interface strength of thermoset nanocomposites.

Science.gov (United States)

Alian, A R; Meguid, S A

2017-02-08

Most existing molecular dynamics simulations in nanoreinforced composites assume carbon nanotubes (CNTs) to be straight and uniformly dispersed within thermoplastics. In reality, however, CNTs are typically curved, agglomerated and aggregated as a result of van der Waal interactions and electrostatic forces. In this paper, we account for both curvature and agglomeration of CNTs in extensive molecular dynamic (MD) simulations. The purpose of these simulations is to evaluate the influence of waviness and agglomeration of these curved and agglomerated CNTs on the interfacial strength of thermoset nanocomposite and upon their load transfer capability. Two aspects of the work were accordingly examined. In the first, realistic carbon nanotubes (CNTs) of the same length but varied curvatures were embedded in thermoset polymer composites and simulations of pull-out tests were conducted to evaluate the corresponding interfacial shear strength (ISS). In the second, the effect of the agglomerate size upon the ISS was determined using bundles of CNTs of different diameters. The results of our MD simulations revealed the following. The pull-out force of the curved CNTs is significantly higher than its straight counterpart and increases further with the increase in the waviness of the CNTs. This is attributed to the added pull-out energy dissipated in straightening the CNTs during the pull-out process. It also reveals that agglomeration of CNTs leads to a reduction in the ISS and poor load transferability, and that this reduction is governed by the size of the agglomerate. The simulation results were also used to develop a generalized relation for the ISS that takes into consideration the effect of waviness and agglomeration of CNTs of CNT-polymer composites.

Absorption homogenization at wavy melt films by CO{sub 2}-lasers in contrast to 1 μm-wavelength lasers

Energy Technology Data Exchange (ETDEWEB)

Kaplan, Alexander F.H., E-mail: alexander.kaplan@ltu.se

2015-02-15

Highlights: • The absorption distribution of 1 μm wavelength lasers compared to 10 μm CO{sub 2}-lasers across a wavy molten steel surface is calculated, at grazing angle of incidence. • For a wide range of surface waviness parameters the CO{sub 2}-laser shows a much more homogenizing absorption behaviour than 1 μm-lasers. • Although the interaction is very complex and non-linear, it is fundamental and very distinct between CO{sub 2}-lasers and 1 μm-lasers, due to their very different Fresnel-absorption characteristics. • The strong local absorption peaks for 1 μm-lasers can cause very strong local boiling and amplification of surface waves, in good correlation to empirical experimental trends. • Such differences can in turn have strong consequences during laser materials processing like laser keyhole welding, laser drilling or laser remote fusion cutting. - Abstract: For wavy metal melts, across a wide range of their topology parameters, lasers with about 1 μm wavelength experience the highest Fresnel absorption around the shoulders of the waves. Calculations show that this induces a strong peak of the absorbed power density of the laser beam. The high temperature gradients have the potential to cause very local boiling and growth of the valleys. In contrast, for a certain parameter category the small Brewster angle for the CO{sub 2}-laser partially homogenizes the temperatures by elevated absorption at domains of grazing incidence. This has the potential to cause opposite consequences on the process, like wave smoothing.

Computer models for fading channels with applications to digital transmission

Science.gov (United States)

Loo, Chun; Secord, Norman

1991-11-01

The authors describe computer models for Rayleigh, Rician, log-normal, and land-mobile-satellite fading channels. All computer models for the fading channels are based on the manipulation of a white Gaussian random process. This process is approximated by a sum of sinusoids with random phase angle. These models compare very well with analytical models in terms of their probability distribution of envelope and phase of the fading signal. For the land mobile satellite fading channel, results of level crossing rate and average fade duration are given. These results show that the computer models can provide a good coarse estimate of the time statistic of the faded signal. Also, for the land-mobile-satellite fading channel, the results show that a 3-pole Butterworth shaping filter should be used with the model. An example of the application of the land-mobile-satellite fading-channel model to predict the performance of a differential phase-shift keying signal is described.

Chaotic diffusion in steady wavy vortex flow-Dependence on wave state and correlation with Eulerian symmetry measures

Energy Technology Data Exchange (ETDEWEB)

King, G P [Instituto de Oceanografia, Faculdade de Ciencias, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa (Portugal); Rudman, Murray [CSIRO Manufacturing and Infrastructure Technology, P.O. Box 56, Highett, Vic. 3190 (Australia); Rowlands, G [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom)], E-mail: gkinglisboa@gmail.com, E-mail: Murray.Rudman@csiro.au, E-mail: G.Rowlands@warwick.ac.uk

2008-01-31

The dimensionless effective axial diffusion coefficient, D{sub z}, calculated from particle trajectories in steady wavy vortex flow in a narrow gap Taylor-Couette system, has been determined as a function of Reynolds number (R = Re/Re{sub c}), axial wavelength ({lambda}{sub z}), and the number of azimuthal waves (m). Two regimes of Reynolds number were found: (i) when R < 3.5, D{sub z} has a complex and sometimes multi-modal dependence on Reynolds number; (ii) when R > 3.5, D{sub z} decreases monotonically. Eulerian quantities measuring the departure from rotational symmetry, {psi}{sub {theta}}, and flexion-free flow, {psi}{sub {nu}}, were calculated. The space-averaged quantities {phi}-bar{sub {theta}} and {phi}-bar{sub {nu}} were found to have, unlike D{sub z}, a simple unimodal dependence on R. In the low R regime the correlation between D{sub z} and {psi}{sub {theta}}{psi}{sub {nu}} was complicated and was attributed to variations in the spatial distribution of the wavy disturbance occurring in this range of R. In the large R regime, however, the correlation simplified to D{sub z}{approx}{phi}-bar{sub {theta}}{phi}-bar{sub {nu}} for all wave states, and this was attributed to the growth of an integrable vortex core and the concentration of the wavy disturbance into narrow regions near the outflow and inflow jets. A reservoir model of a wavy vortex was used to determine the rate of escape across the outflow and inflow boundaries, the size of the 'escape basins' (associated with escape across the outflow and inflow boundaries), and the size of the trapping region in the vortex core. In the low R regime after the breakup of all KAM tori, the outflow basin ({gamma}{sub O}) is larger than the inflow basin ({gamma}{sub I}), and both {gamma}{sub O} and {gamma}{sub I} are (approximately) independent of R. In the large R regime, with increasing Reynolds number the trapping region grows, the outflow basin decreases, and the inflow basin shows a slight increase

Dietary macronutrients and the aging liver sinusoidal endothelial cell.

Science.gov (United States)

Cogger, Victoria Carroll; Mohamad, Mashani; Solon-Biet, Samantha Marie; Senior, Alistair M; Warren, Alessandra; O'Reilly, Jennifer Nicole; Tung, Bui Thanh; Svistounov, Dmitri; McMahon, Aisling Clare; Fraser, Robin; Raubenheimer, David; Holmes, Andrew J; Simpson, Stephen James; Le Couteur, David George

2016-05-01

Fenestrations are pores within the liver sinusoidal endothelial cells (LSECs) that line the sinusoids of the highly vascularized liver. Fenestrations facilitate the transfer of substrates between blood and hepatocytes. With pseudocapillarization of the hepatic sinusoid in old age, there is a loss of fenestrations. LSECs are uniquely exposed to gut-derived dietary and microbial substrates delivered by the portal circulation to the liver. Here we studied the effect of 25 diets varying in content of macronutrients and energy on LSEC fenestrations using the Geometric Framework method in a large cohort of mice aged 15 mo. Macronutrient distribution rather than total food or energy intake was associated with changes in fenestrations. Porosity and frequency were inversely associated with dietary fat intake, while fenestration diameter was inversely associated with protein or carbohydrate intake. Fenestrations were also linked to diet-induced changes in gut microbiome, with increased fenestrations associated with higher abundance of Firmicutes and reduced abundance of Bacteroidetes Diet-induced changes in levels of several fatty acids (C16:0, C19:0, and C20:4) were also significantly inversely associated with fenestrations, suggesting a link between dietary fat and modulation of lipid rafts in the LSECs. Diet influences fenestrations and these data reflect both the key role of the LSECs in clearing gut-derived molecules from the vascular circulation and the impact these molecules have on LSEC morphology. Copyright © 2016 the American Physiological Society.

Evoked responses to sinusoidally modulated sound in unanaesthetized dogs

NARCIS (Netherlands)

Tielen, A.M.; Kamp, A.; Lopes da Silva, F.H.; Reneau, J.P.; Storm van Leeuwen, W.

1. 1. Responses evoked by sinusoidally amplitude-modulated sound in unanaesthetized dogs have been recorded from inferior colliculus and from auditory cortex structures by means of chronically indwelling stainless steel wire electrodes. 2. 2. Harmonic analysis of the average responses demonstrated

Optimization for sinusoidal profiles in surface relief gratings ...

Indian Academy of Sciences (India)

2014-02-07

Feb 7, 2014 ... filometry [7–9] and monitoring of surface self-diffusion of solids under ultrahigh vacuum conditions [10]. In the present work, recording parameters, i.e. exposure time and deve- lopment time for fabrication of such holographic gratings have been optimized to obtain nearly perfect sinusoidal profiles in the ...

Asymptotic Theory of the Least Squares Estimators of Sinusoidal Signal

National Research Council Canada - National Science Library

Kundu, Debasis

1997-01-01

... normality are derived for the sinusoidal signal under the assumption of normal error (Kundu; 1993) and under the assumptions of independent and identically distributed random variables in Kundu and Mitra...

Dynamic performance of maximum power point tracking circuits using sinusoidal extremum seeking control for photovoltaic generation

Science.gov (United States)

Leyva, R.; Artillan, P.; Cabal, C.; Estibals, B.; Alonso, C.

2011-04-01

The article studies the dynamic performance of a family of maximum power point tracking circuits used for photovoltaic generation. It revisits the sinusoidal extremum seeking control (ESC) technique which can be considered as a particular subgroup of the Perturb and Observe algorithms. The sinusoidal ESC technique consists of adding a small sinusoidal disturbance to the input and processing the perturbed output to drive the operating point at its maximum. The output processing involves a synchronous multiplication and a filtering stage. The filter instance determines the dynamic performance of the MPPT based on sinusoidal ESC principle. The approach uses the well-known root-locus method to give insight about damping degree and settlement time of maximum-seeking waveforms. This article shows the transient waveforms in three different filter instances to illustrate the approach. Finally, an experimental prototype corroborates the dynamic analysis.

Studies on diversion cross-flow between two parallel channels communicating by a lateral slot. II

International Nuclear Information System (INIS)

Tapucu, A.; Merilo, M.

1977-01-01

The axial pressure variations of two parallel channels with single phase flows communicating by a long lateral slot have been studied experimentally. Using mass and momentum conservation principles, the axial pressure variations have been derived in terms of two parameters ksub(d) and ksub(r), for donor and recipient channels, respectively. These parameters include the combined effect of fluid transferred from donor to recipient channel, and drag force brought on by the connection gap, and are functions of the velocities and slot geometry parameters. A pressure difference oscillation between channels along the slot has been detected which is sinusoidal with wave lengths which seem to be a function of the gap clearance. (Auth.)

Estimation of the second heart sound split using windowed sinusoidal models

DEFF Research Database (Denmark)

Sæderup, Rasmus Gundorf; Hoang, Poul; Winther, Simon

2018-01-01

to the potential overlap between A2 and P2. In this paper, a model-based approach is proposed where both A2 and P2 are modeled as windowed sinusoids with their sum forming the S2 signal. Estimation of the model parameters and the S2 split form a non-convex optimization problem, where a local minimum is obtained...... using a sequential optimization procedure. First, the window parameters are found as the solution to a regularized least squares problem. Then, the frequencies and phases of the sinusoids are found by locating the maximal peaks of the heart signals’ frequency magnitudes, and using the corresponding...

Sinusoidal modulation analysis for optical system MTF measurements.

Science.gov (United States)

Boone, J M; Yu, T; Seibert, J A

1996-12-01

The modulation transfer function (MTF) is a commonly used metric for defining the spatial resolution characteristics of imaging systems. While the MTF is defined in terms of how an imaging system demodulates the amplitude of a sinusoidal input, this approach has not been in general use to measure MTFs in the medical imaging community because producing sinusoidal x-ray patterns is technically difficult. However, for optical systems such as charge coupled devices (CCD), which are rapidly becoming a part of many medical digital imaging systems, the direct measurement of modulation at discrete spatial frequencies using a sinusoidal test pattern is practical. A commercially available optical test pattern containing spatial frequencies ranging from 0.375 cycles/mm to 80 cycles/mm was sued to determine the MRF of a CCD-based optical system. These results were compared with the angulated slit method of Fujita [H. Fujita, D. Tsia, T. Itoh, K. Doi, J. Morishita, K. Ueda, and A. Ohtsuka, "A simple method for determining the modulation transfer function in digital radiography," IEEE Trans. Medical Imaging 11, 34-39 (1992)]. The use of a semiautomated profiled iterated reconstruction technique (PIRT) is introduced, where the shift factor between successive pixel rows (due to angulation) is optimized iteratively by least-squares error analysis rather than by hand measurement of the slit angle. PIRT was used to find the slit angle for the Fujita technique and to find the sine-pattern angle for the sine-pattern technique. Computer simulation of PIRT for the case of the slit image (a line spread function) demonstrated that it produced a more accurate angle determination than "hand" measurement, and there is a significant difference between the errors in the two techniques (Wilcoxon Signed Rank Test, p < 0.001). The sine-pattern method and the Fujita slit method produced comparable MTF curves for the CCD camera evaluated.

Modelling the static contact between a fingertip and a rigid wavy surface

NARCIS (Netherlands)

Rodriguez Urribarri, Adriana; van der Heide, Emile; Zeng, Xiangqiong; de Rooij, Matthias B.

2016-01-01

Surface topography is one of the major parameters affecting friction during touch and consequently tactility. In order to understand and control friction, fine controlled surfaces with a sinusoidal topography are studied to derive an analytical contact model. The Westergaard model on a

Increased sinusoidal volume and solute extraction during retrograde liver perfusion

International Nuclear Information System (INIS)

Bass, N.M.; Manning, J.A.; Weisiger, R.A.

1989-01-01

Retrograde isolated liver perfusion has been used to probe acinar functional heterogeneity, but the hemodynamic effects of backward flow have not been characterized. In this study, extraction of a long-chain fatty acid derivative, 12-N-methyl-7-nitrobenzo-2-oxa-1,3-diazol-amino stearate (12-NBDS), was greater during retrograde than during anterograde perfusion of isolated rat liver. To determine whether hemodynamic differences between anterograde and retrograde perfused livers could account for this finding, the hepatic extracellular space was measured for both directions of flow by means of [ 14 C]sucrose washout during perfusion as well as by direct measurement of [ 14 C]sucrose entrapped during perfusion. A three- to fourfold enlargement of the total hepatic extracellular space was found during retrograde perfusion by both approaches. Examination of perfusion-fixed livers by light microscopy and morphometry revealed that marked distension of the sinusoids occurred during retrograde perfusion and that this accounts for the observed increase in the [ 14 C]sucrose space. These findings support the hypothesis that maximum resistance to perfusate flow in the isolated perfused rat liver is located at the presinusoidal level. In addition, increased transit time of perfusate through the liver and greater sinusoidal surface area resulting from sinusoidal distension may account for the higher extraction of 12-NBDS and possibly other compounds by retrograde perfused liver

BPM Offset Determination by Sinusoidal Quadrupole K-modulation

CERN Document Server

Baer, T; Wenninger, J

2011-01-01

To ensure an adequate orbit steering that maximizes the machine aperture, a good knowledge of the BPM measurement offsets is crucial. During this MD, a sinusoidal k-modulation of individually powered quadrupoles was performed to determine the offsets of the nearby BPMs. An accuracy of 10µm for the determination of the absolute beam position is reached.

Band structure and optical properties of sinusoidal superlattices: ZnSe1-xTex

International Nuclear Information System (INIS)

Yang, G.; Lee, S.; Furdyna, J. K.

2000-01-01

This paper examines the band structure and optical selection rules in superlattices with a sinusoidal potential profile. The analysis is motivated by the recent successful fabrication of high quality ZnSe 1-x Te x superlattices in which the composition x varies sinusoidally along the growth direction. Although the band alignment in the ZnSe 1-x Te x sinusoidal superlattices is staggered (type II), they exhibit unexpectedly strong photoluminescence, thus suggesting interesting optical behavior. The band structure of such sinusoidal superlattices is formulated in terms of the nearly-free-electron (NFE) approximation, in which the superlattice potential is treated as a perturbation. The resulting band structure is unique, characterized by a single minigap separating two wide, free-electron-like subbands for both electrons and holes. Interband selection rules are derived for optical transitions involving conduction and valence-band states at the superlattice Brillouin-zone center, and at the zone edge. A number of transitions are predicted due to wave-function mixing of different subband states. It should be noted that the zone-center and zone-edge transitions are especially easy to distinguish in these superlattices because of the large width of the respective subbands. The results of the NFE approximation are shown to hold surprisingly well over a wide range of parameters, particularly when the period of the superlattice is short. (c) 2000 The American Physical Society

A Joint Approach for Single-Channel Speaker Identification and Speech Separation

DEFF Research Database (Denmark)

Mowlaee, Pejman; Saeidi, Rahim; Christensen, Mads Græsbøll

2012-01-01

) accuracy, here, we report the objective and subjective results as well. The results show that the proposed system performs as well as the best of the state-of-the-art in terms of perceived quality while its performance in terms of speaker identification and automatic speech recognition results......In this paper, we present a novel system for joint speaker identification and speech separation. For speaker identification a single-channel speaker identification algorithm is proposed which provides an estimate of signal-to-signal ratio (SSR) as a by-product. For speech separation, we propose...... a sinusoidal model-based algorithm. The speech separation algorithm consists of a double-talk/single-talk detector followed by a minimum mean square error estimator of sinusoidal parameters for finding optimal codevectors from pre-trained speaker codebooks. In evaluating the proposed system, we start from...

Biphase sinusoidal oscillator based on negative resistor.

Science.gov (United States)

Bayard, Jean

2010-06-01

This paper describes a biphase sinusoidal generator which provides two signals: v(ref)=V(M) sin(omegat) and v(out)=V(M) sin(omegat+DeltaPhi), where DeltaPhi is in the range 0, pi/2 or -pi/2, 0 and is not dependent on the frequency value. It is based on a negative resistor and it requires very few components. SPICE simulations and measurements on an experimental setup confirm the theoretical analysis.

The two dynamical states in sinusoidal potentials: An analog simulation experiment

Science.gov (United States)

Sawkmie, Ivan Skhem; Mahato, Mangal C.

2018-04-01

The phenomenon of stochastic resonance (SR) is usually found to occur theoretically as well as experimentally in bi-stable systems [1]. Recently, it was numerically shown that SR is found to occur in underdamped (friction coefficient γ) sinusoidal potentials also. The occurrence of SR is explained in terms of two competing dynamical states of trajectories as a response to the external periodic drive. We setup an analog simulation experiment similar to the analog simulation work done earlier to study stochastic nonlinear dynamics [2], to verify the existence of the two dynamical states and to investigate the occurrence of SR in sinusoidal potentials obtained earlier [3]. We discuss our experimental setup and the results obtained in detail.

Near-field interaction of colloid near wavy walls

Science.gov (United States)

Luo, Yimin; Serra, Francesca; Wong, Denise; Steager, Edward; Stebe, Kathleen

Anisotropic media can be used to manipulate colloids, in tandem with carefully designed boundary conditions. For example, in bulk nematic liquid crystal, a wall with homeotropic anchoring repels a colloid with the same anchoring; yet by changing the surface topography from planar to concave, one can turn repulsion into attraction. We explore the behaviors of micro-particles with associated topological defects (hedgehogs or Saturn rings) near wavy walls. The walls locally excite disturbance, which decays into bulk. The range of influence is related to the curvature. The distortion can be used to position particles, either directly on the structure or at a distance away, based on the ``splay-matching'' rules. When distortion becomes stronger through the deepening of the well, the splay field created by the wall can prompt transformation from a Saturn ring to a hedgehog. We combine wells of different wavelength and depth to direct colloid movement. We apply a magnetic field to reset the initial position of ferromagnetic colloids and subsequently release them to probe the elastic energy landscape. Our platform enables manipulation, particle selection, and a detailed study of defect structure under the influence of curvature. Army Research Office.

Fibronectin Extra Domain A Promotes Liver Sinusoid Repair following Hepatectomy.

Directory of Open Access Journals (Sweden)

Bridget Sackey-Aboagye

Full Text Available Liver sinusoidal endothelial cells (LSECs are the main endothelial cells in the liver and are important for maintaining liver homeostasis as well as responding to injury. LSECs express cellular fibronectin containing the alternatively spliced extra domain A (EIIIA-cFN and increase expression of this isoform after liver injury, although its function is not well understood. Here, we examined the role of EIIIA-cFN in liver regeneration following partial hepatectomy. We carried out two-thirds partial hepatectomies in mice lacking EIIIA-cFN and in their wild type littermates, studied liver endothelial cell adhesion on decellularized, EIIIA-cFN-containing matrices and investigated the role of cellular fibronectins in liver endothelial cell tubulogenesis. We found that liver weight recovery following hepatectomy was significantly delayed and that sinusoidal repair was impaired in EIIIA-cFN null mice, especially females, as was the lipid accumulation typical of the post-hepatectomy liver. In vitro, we found that liver endothelial cells were more adhesive to cell-deposited matrices containing the EIIIA domain and that cellular fibronectin enhanced tubulogenesis and vascular cord formation. The integrin α9β1, which specifically binds EIIIA-cFN, promoted tubulogenesis and adhesion of liver endothelial cells to EIIIA-cFN. Our findings identify a role for EIIIA-cFN in liver regeneration and tubulogenesis. We suggest that sinusoidal repair is enhanced by increased LSEC adhesion, which is mediated by EIIIA-cFN.

Measurement of electroosmotic and electrophoretic velocities using pulsed and sinusoidal electric fields.

Science.gov (United States)

Sadek, Samir H; Pimenta, Francisco; Pinho, Fernando T; Alves, Manuel A

2017-04-01

In this work, we explore two methods to simultaneously measure the electroosmotic mobility in microchannels and the electrophoretic mobility of micron-sized tracer particles. The first method is based on imposing a pulsed electric field, which allows to isolate electrophoresis and electroosmosis at the startup and shutdown of the pulse, respectively. In the second method, a sinusoidal electric field is generated and the mobilities are found by minimizing the difference between the measured velocity of tracer particles and the velocity computed from an analytical expression. Both methods produced consistent results using polydimethylsiloxane microchannels and polystyrene micro-particles, provided that the temporal resolution of the particle tracking velocimetry technique used to compute the velocity of the tracer particles is fast enough to resolve the diffusion time-scale based on the characteristic channel length scale. Additionally, we present results with the pulse method for viscoelastic fluids, which show a more complex transient response with significant velocity overshoots and undershoots after the start and the end of the applied electric pulse, respectively. © 2016 The Authors. Electrophoresis published by Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Measurement of definite integral of sinusoidal signal absolute value third power using digital stochastic method

Directory of Open Access Journals (Sweden)

Beljić Željko

2017-01-01

Full Text Available In this paper a special case of digital stochastic measurement of the third power of definite integral of sinusoidal signal’s absolute value, using 2-bit AD converters is presented. This case of digital stochastic method had emerged from the need to measure power and energy of the wind. Power and energy are proportional to the third power of wind speed. Anemometer output signal is sinusoidal. Therefore an integral of the third power of sinusoidal signal is zero. Two approaches are proposed for the third power calculation of the wind speed signal. One approach is to use absolute value of sinusoidal signal (before AD conversion for which there is no need of multiplier hardware change. The second approach requires small multiplier hardware change, but input signal remains unchanged. For the second approach proposed minimal hardware change was made to calculate absolute value of the result after AD conversion. Simulations have confirmed theoretical analysis. Expected precision of wind energy measurement of proposed device is better than 0,00051% of full scale. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. TR32019

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

Directory of Open Access Journals (Sweden)

Emad Hosseinpour

2015-01-01

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

Biased and flow driven Brownian motion in periodic channels

Science.gov (United States)

Martens, S.; Straube, A.; Schmid, G.; Schimansky-Geier, L.; Hänggi, P.

2012-02-01

In this talk we will present an expansion of the common Fick-Jacobs approximation to hydrodynamically as well as by external forces driven Brownian transport in two-dimensional channels exhibiting smoothly varying periodic cross-section. We employ an asymptotic analysis to the components of the flow field and to stationary probability density for finding the particles within the channel in a geometric parameter. We demonstrate that the problem of biased Brownian dynamics in a confined 2D geometry can be replaced by Brownian motion in an effective periodic one-dimensional potential ψ(x) which takes the external bias, the change of the local channel width, and the flow velocity component in longitudinal direction into account. In addition, we study the influence of the external force magnitude, respectively, the pressure drop of the fluid on the particle transport quantities like the averaged velocity and the effective diffusion coefficient. The critical ratio between the external force and pressure drop where the average velocity equals zero is identified and the dependence of the latter on the channel geometry is derived. Analytic findings are confirmed by numerical simulations of the particle dynamics in a reflection symmetric sinusoidal channel.

Physical optimization of a wavy porous cavity filled by nanofluids in the presence of solar radiations using the Box-Behnken design (BBD)

Science.gov (United States)

Ghorbanian, A.; Tahari, M.; Hatami, M.

2017-06-01

In this paper, the physical optimization of a wavy porous cavity is evaluated while it is filled with nanofluids and under the solar radiation heat flux by using numerical and statistical methods. The effect of four parameters is discussed on the Nusselt number: Wavy amplitude ( Am, solar heat flux, Darcy number and Rayleigh number. To find the effect and interaction of these parameters on the heat transfer, a Box-Behnken design (BBD) is used and analysis is performed on the 27 experiments proposed by BBD. Analysis of variance (ANOVA) of the results revealed that solar heat flux and wave amplitude have a strong effect on the Nusselt number compared to Darcy and Rayleigh numbers. Finally, the response surface methodology (RSM) was applied to find the optimized case while its error was 0.002% in predicting the Nusselt number for the optimized case which confirms the high accuracy of results.

Removal of Stationary Sinusoidal Noise from Random Vibration Signals.

Energy Technology Data Exchange (ETDEWEB)

Johnson, Brian; Cap, Jerome S.

2018-02-01

In random vibration environments, sinusoidal line noise may appear in the vibration signal and can affect analysis of the resulting data. We studied two methods which remove stationary sine tones from random noise: a matrix inversion algorithm and a chirp-z transform algorithm. In addition, we developed new methods to determine the frequency of the tonal noise. The results show that both of the removal methods can eliminate sine tones in prefabricated random vibration data when the sine-to-random ratio is at least 0.25. For smaller ratios down to 0.02 only the matrix inversion technique can remove the tones, but the metrics to evaluate its effectiveness also degrade. We also found that using fast Fourier transforms best identified the tonal noise, and determined that band-pass-filtering the signals prior to the process improved sine removal. When applied to actual vibration test data, the methods were not as effective at removing harmonic tones, which we believe to be a result of mixed-phase sinusoidal noise.

Using piecewise sinusoidal basis functions to blanket multiple wire segments

CSIR Research Space (South Africa)

Lysko, AA

2009-06-01

Full Text Available This paper discusses application of the piecewise sinusoidal (PWS) basis function (BF) over a chain of several wire segments, for example as a multiple domain basis function. The usage of PWS BF is compared to results based on the piecewise linear...

Sinusoidal velaroidal shell – numerical modelling of the nonlinear ...

African Journals Online (AJOL)

The nonlinearity, applied to a sinusoidal velaroidal shell with the inner radius r0, the outer variables radii from 10m to 20m and the number of waves n=8, will give rise to the investigation of its nonlinear buckling resistance. The building material is a high-performant concrete. The investigation emphasizes more on the ...

Electric stimulation with sinusoids and white noise for neural prostheses

Directory of Open Access Journals (Sweden)

Daniel K Freeman

2010-02-01

Full Text Available We are investigating the use of novel stimulus waveforms in neural prostheses to determine whether they can provide more precise control over the temporal and spatial pattern of elicited activity as compared to conventional pulsatile stimulation. To study this, we measured the response of retinal ganglion cells to both sinusoidal and white noise waveforms. The use of cell-attached and whole cell patch clamp recordings allowed the responses to be observed without significant obstruction from the stimulus artifact. Electric stimulation with sinusoids elicited robust responses. White noise analysis was used to derive the linear kernel for the ganglion cell’s spiking response as well as for the underlying excitatory currents. These results suggest that in response to electric stimulation, presynaptic retinal neurons exhibit bandpass filtering characteristics with peak response that occur 25ms after onset. The experimental approach demonstrated here may be useful for studying the temporal response properties of other neurons in the CNS.

New Canonic Active RC Sinusoidal Oscillator Circuits Using Second-Generation Current Conveyors with Application as a Wide-Frequency Digitally Controlled Sinusoid Generator

OpenAIRE

Abhirup Lahiri

2011-01-01

This paper reports two new circuit topologies using second-generation current conveyors (CCIIs) for realizing variable frequency sinusoidal oscillators with minimum passive components. The proposed topologies in this paper provide new realizations of resistance-controlled and capacitor-controlled variable frequency oscillators (VFOs) using only four passive components. The first topology employs three CCIIs, while the second topology employs two CCIIs. The second topology provides an advantag...

Couple stress fluid flow in a rotating channel with peristalsis

Science.gov (United States)

Abd elmaboud, Y.; Abdelsalam, Sara I.; Mekheimer, Kh. S.

2018-04-01

This article describes a new model for obtaining closed-form semi-analytical solutions of peristaltic flow induced by sinusoidal wave trains propagating with constant speed on the walls of a two-dimensional rotating infinite channel. The channel rotates with a constant angular speed about the z - axis and is filled with couple stress fluid. The governing equations of the channel deformation and the flow rate inside the channel are derived using the lubrication theory approach. The resulting equations are solved, using the homotopy perturbation method (HPM), for exact solutions to the longitudinal velocity distribution, pressure gradient, flow rate due to secondary velocity, and pressure rise per wavelength. The effect of various values of physical parameters, such as, Taylor's number and couple stress parameter, together with some interesting features of peristaltic flow are discussed through graphs. The trapping phenomenon is investigated for different values of parameters under consideration. It is shown that Taylor's number and the couple stress parameter have an increasing effect on the longitudinal velocity distribution till half of the channel, on the flow rate due to secondary velocity, and on the number of closed streamlines circulating the bolus.

MHD natural convection from a heated vertical wavy surface with variable viscosity and thermal conductivity

International Nuclear Information System (INIS)

Choudhury, M.; Hazarika, G.C.; Sibanda, P.

2013-01-01

We investigate the effects of temperature dependent viscosity and thermal conductivity on natural convection flow of a viscous incompressible electrically conducting fluid along a vertical wavy surface. The flow is permeated by uniform transverse magnetic field. The fluid viscosity and thermal conductivity are assumed to vary as inverse linear functions of temperature. The coupled non-linear systems of partial differential equations are solved using the finite difference method. The effects of variable viscosity parameter, variable thermal conductivity parameter and magnetic parameter on the flow field and the heat transfer characteristics are discussed and shown graphically. (author)

Pelagic behaviour of reservoir fishes: sinusoidal swimming and associated behaviour

OpenAIRE

JAROLÍM, Oldřich

2009-01-01

Annotation Long-term fixed-location hydroacoustic study with uplooking transducer was performed during 2005 in Římov reservoir, Czech Republic. It dealt mainly with fish behaviour in the open water of reservoir, especially with sinusoidal swimming behaviour. The dependence of pelagic fish behaviour on environmental conditions was also studied.

Stochastic analysis/synthesis using sinusoidal atoms

DEFF Research Database (Denmark)

Jensen, Kristoffer

2008-01-01

This work proposes a method for re-synthesizing music for use in perceptual experiments regarding structural changes and in music creation. Atoms are estimated from music audio, modelled in a stochastic model, and re-synthesized from the model pa- rameters. The atoms are found by splitting...... sinusoids into short segments, and modelled into amplitude and envelope shape, frequency, time and duration. A simple model for creating envelopes with percussive, sustained or crescendo shape is presented. Single variable and joint probability density functions are created from the atom parameters and used...... to re-create sounds with the same distribution of the atoms parameters. A novel method for visualization music, the musigram, permits a better understanding of the re- synthesized sounds....

A Perceptual Model for Sinusoidal Audio Coding Based on Spectral Integration

NARCIS (Netherlands)

Van de Par, S.; Kohlrausch, A.; Heusdens, R.; Jensen, J.; Holdt Jensen, S.

2005-01-01

Psychoacoustical models have been used extensively within audio coding applications over the past decades. Recently, parametric coding techniques have been applied to general audio and this has created the need for a psychoacoustical model that is specifically suited for sinusoidal modelling of

A perceptual model for sinusoidal audio coding based on spectral integration

NARCIS (Netherlands)

Van de Par, S.; Kohlrauch, A.; Heusdens, R.; Jensen, J.; Jensen, S.H.

2005-01-01

Psychoacoustical models have been used extensively within audio coding applications over the past decades. Recently, parametric coding techniques have been applied to general audio and this has created the need for a psychoacoustical model that is specifically suited for sinusoidal modelling of

Auxetic hexachiral structures with wavy ligaments for large elasto-plastic deformation

Science.gov (United States)

Zhu, Yilin; Wang, Zhen-Pei; Hien Poh, Leong

2018-05-01

The hexachiral structure is in-plane isotropic in small deformation. When subjected to large elasto-plastic deformation, however, the hexachiral structure tends to lose its auxeticity and/or isotropy—properties which are desirable in many potential applications. The objective of this study is to improve these two mechanical properties, without significantly compromising the effective yield stress, in the regime with significant material and geometrical nonlinearity effects. It is found that the deformation mechanisms underlying the auxeticity and isotropy properties of a hexachiral structure are largely influenced by the extent of rotation of the central ring in a unit cell. To facilitate the development of this deformation mechanism, an improved design with wavy ligaments is proposed. The improved performance of the proposed hexachiral structure is demonstrated. An initial study on possible applications as a protective material is next carried out, where the improved hexachiral design is shown to exhibit higher specific energy absorption capacity compared to the original design, as well as standard honeycomb structures.

Impact Testing and Simulation of a Sinusoid Foam Sandwich Energy Absorber

Science.gov (United States)

Jackson, Karen E.; Fasanella, Edwin L; Littell, Justin D.

2015-01-01

A sinusoidal-shaped foam sandwich energy absorber was developed and evaluated at NASA Langley Research Center through multi-level testing and simulation performed under the Transport Rotorcraft Airframe Crash Testbed (TRACT) research project. The energy absorber, designated the "sinusoid," consisted of hybrid carbon- Kevlar® plain weave fabric face sheets, two layers for each face sheet oriented at +/-45deg with respect to the vertical or crush direction, and a closed-cell ELFOAM(TradeMark) P200 polyisocyanurate (2.0-lb/ft3) foam core. The design goal for the energy absorber was to achieve an average floor-level acceleration of between 25- and 40-g during the full-scale crash test of a retrofitted CH-46E helicopter airframe, designated TRACT 2. Variations in the design were assessed through quasi-static and dynamic crush testing of component specimens. Once the design was finalized, a 5-ft-long subfloor beam was fabricated and retrofitted into a barrel section of a CH-46E helicopter. A vertical drop test of the barrel section was conducted onto concrete to evaluate the performance of the energy absorber prior to retrofit into TRACT 2. Finite element models were developed of all test articles and simulations were performed using LSDYNA ®, a commercial nonlinear explicit transient dynamic finite element code. Test analysis results are presented for the sinusoid foam sandwich energy absorber as comparisons of load-displacement and acceleration-time-history responses, as well as predicted and experimental structural deformations and progressive damage for each evaluation level (component testing through barrel section drop testing).

Sinusoidal obstruction syndrome (SOS): A light and electron microscopy study in human liver.

Science.gov (United States)

Vreuls, C P H; Driessen, A; Olde Damink, S W M; Koek, G H; Duimel, H; van den Broek, M A J; Dejong, C H C; Braet, F; Wisse, E

2016-05-01

Oxaliplatin is an important chemotherapeutic agent, used in the treatment of hepatic colorectal metastases, and known to induce the sinusoidal obstruction syndrome (SOS). Pathophysiological knowledge concerning SOS is based on a rat model. Therefore, the aim was to perform a comprehensive study of the features of human SOS, using both light microscopy (LM) and electron microscopy (EM). Included were all patients of whom wedge liver biopsies were collected during a partial hepatectomy for colorectal liver metastases, in a 4-year period. The wedge biopsy were perfusion fixated and processed for LM and EM. The SOS lesions were selected by LM and details were studied using EM. Material was available of 30 patients, of whom 28 patients received neo-adjuvant oxaliplatin. Eighteen (64%) of the 28 patients showed SOS lesions, based on microscopy. The lesions consisted of sinusoidal endothelial cell detachment from the space of Disse on EM. In the enlarged space of Disse a variable amount of erythrocytes were located. Sinusoidal endothelial cell detachment was present in human SOS, accompanied by enlargement of the space of Disse and erythrocytes in this area. These findings, originally described in a rat model, were now for the first time confirmed in human livers under clinically relevant settings. Copyright © 2016 Elsevier Ltd. All rights reserved.

Channel noise enhances signal detectability in a model of acoustic neuron through the stochastic resonance paradigm.

Science.gov (United States)

Liberti, M; Paffi, A; Maggio, F; De Angelis, A; Apollonio, F; d'Inzeo, G

2009-01-01

A number of experimental investigations have evidenced the extraordinary sensitivity of neuronal cells to weak input stimulations, including electromagnetic (EM) fields. Moreover, it has been shown that biological noise, due to random channels gating, acts as a tuning factor in neuronal processing, according to the stochastic resonant (SR) paradigm. In this work the attention is focused on noise arising from the stochastic gating of ionic channels in a model of Ranvier node of acoustic fibers. The small number of channels gives rise to a high noise level, which is able to cause a spike train generation even in the absence of stimulations. A SR behavior has been observed in the model for the detection of sinusoidal signals at frequencies typical of the speech.

Electronically tunable RC sinusoidal oscillators

International Nuclear Information System (INIS)

Florescu, Valeriu

2008-01-01

This paper presents two types of active configurations for realizing electronically tunable RC sinusoidal oscillators. The type-1 network employs two grounded scaled resistances KR 1 and KR 2 , where K is scaling factor. The frequency of oscillation W 0 is controlled conveniently by adjusting K, since W 0 appears in the form W 0 =1/K √ R 1 C 1 R 2 C 2 . For realizing the scaled resistances, an active configuration is proposed, which realizes KR 1 =R 1 /(1+f(V B )), where f(V B ) denotes a function of a controlling voltage V B . Thus the frequency tuning can be effected by controlling a voltage V B . The type-2 oscillator uses two periodically switched conductances. It is shown that the tuning of oscillation frequency can be done by varying the pulse width-to-period ratio (t/T) of the periodically switched conductances. (author)

Core losses of a permanent magnet synchronous motor with an amorphous stator core under inverter and sinusoidal excitations

Science.gov (United States)

Yao, Atsushi; Sugimoto, Takaya; Odawara, Shunya; Fujisaki, Keisuke

2018-05-01

We report core loss properties of permanent magnet synchronous motors (PMSM) with amorphous magnetic materials (AMM) core under inverter and sinusoidal excitations. To discuss the core loss properties of AMM core, a comparison with non-oriented (NO) core is also performed. In addition, based on both experiments and numerical simulations, we estimate higher (time and space) harmonic components of the core losses under inverter and sinusoidal excitations. The core losses of PMSM are reduced by about 59% using AMM stator core instead of NO core under sinusoidal excitation. We show that the average decrease obtained by using AMM instead of NO in the stator core is about 94% in time harmonic components.

Core losses of a permanent magnet synchronous motor with an amorphous stator core under inverter and sinusoidal excitations

Directory of Open Access Journals (Sweden)

Atsushi Yao

2018-05-01

Full Text Available We report core loss properties of permanent magnet synchronous motors (PMSM with amorphous magnetic materials (AMM core under inverter and sinusoidal excitations. To discuss the core loss properties of AMM core, a comparison with non-oriented (NO core is also performed. In addition, based on both experiments and numerical simulations, we estimate higher (time and space harmonic components of the core losses under inverter and sinusoidal excitations. The core losses of PMSM are reduced by about 59% using AMM stator core instead of NO core under sinusoidal excitation. We show that the average decrease obtained by using AMM instead of NO in the stator core is about 94% in time harmonic components.

Mapping surface properties of sinusoidal roughness standards by TPM

International Nuclear Information System (INIS)

Liu, X; Rubert, P

2005-01-01

We report our investigation on the surface properties of sinusoidal roughness standards made from pure electroformed nickel. Two specimens having a sinusoidal profile with nominal R a of 0.36 μm and a peak spacing of 25 μm are chosen for this investigation. One specimen is further treated with a hard protective coating of nickel-boron. The surface topography, friction, hardness and Young's modulus of the specimens were measured by a novel instrument, the multi-function Tribological Probe Microscope (TPM). The results show that hardness of these two specimens is 14.1 GPa for uncoated specimen and 25.7 GPa for the coated one, while the Young's modulus is 188 GPa and 225 GPa, respectively. The ramping force was set to 3mN for both the specimens and the effect of the tip penetration was investigated by comparing the topography measurements before and after hardness mapping. It has been found out that there is no significant change in the averaged profiles over the scanned area, which indicates the topography distortion seen in the multi-function mapping, is recoverable. Cross correlation between topography and its corresponding hardness/Young's modulus has been carried out and the result will be discussed in the paper

Hepatic venography in noncirrhotic idiopathic portal hypertension: comparison with cirrhosis of the liver

International Nuclear Information System (INIS)

Futagawa, S.; Fukazawa, M.; Musha, H.

1981-01-01

Free and wedged hepatic venography were carried out in 37 patients with idiopathic portal hypertension (IPH) and the findings compared with those in 88 patients with cirrhosis of the liver. Characteristic changes in IPH included frequent vein-to-vein anastomoses, narrower angles between large veins and their tributaries, smooth and wavy middle-sized to large branches (giving a general ''weeping willow'' appearance), homogeneous sinusoidal filling, and minimal to absent filling of the portal venous system on wedged retrograde portography. In cirrhosis, by contrast, changes included rare vein-to-vein anastomoses, wide angles between veins and tributaries, irregular stenoses of large veins and branches at various levels, spotty sinusoidal filling, and frequent retrograde flow in the portal venous system. Hepatic venography is helpful in differentiating IPH from cirrhosis

Generation of sinusoidal fringes with a holographic phase grating and a phase-only spatial light modulator

International Nuclear Information System (INIS)

Berberova, Natalia; Stoykova, Elena; Sainov, Ventseslav

2012-01-01

A variety of pattern projection methods for the three-dimensional capture of objects is based on the generation of purely sinusoidal fringes. This is not an easy task, especially when a portable non-interferometric system for outdoor usage is required. The use of phase gratings with coherent illumination as a possible solution has the advantage of providing good stability and a large measurement volume. In this work, we analyze the quality of fringes projected with two sinusoidal phase gratings. The first grating is recorded on a silver-halide holographic plate by means of a Michelson interferometer. The spatial resolution of the silver-halide material used is greater than 6000 lines per millimeter, and the recorded grating is practically analogous to a smooth variation of the phase profile. The second grating is formed as a sinusoidal phase variation on a liquid crystal-on-silicon phase-only reflective display with a resolution of 1920×1080 pixels, a pixel pitch of 8 μm and 256 phase levels. The frequency content of the fringes projected with both gratings is analyzed and compared on the basis of the calculated Fresnel diffraction pattern, taking into account that the sinusoidal phase distribution in the case of a spatial light modulator is both sampled and quantized. Experimental fringe patterns projected using both gratings are also provided.

Levitation performance of high-T{sub c} superconductor in sinusoidal guideway magnetic field

Energy Technology Data Exchange (ETDEWEB)

Liu, W. [Applied Superconductivity Laboratory, Southwest Jiaotong University, Chengdu 610031 (China)], E-mail: asclab@asclab.cn; Wang, J.S.; Jing, H.; Jiang, M.; Zheng, J.; Wang, S.Y. [Applied Superconductivity Laboratory, Southwest Jiaotong University, Chengdu 610031 (China)

2008-12-01

The vertical component of the Halbach array's magnetic field exhibits a sinusoid distribution because of the closed magnetic flux area between two neighbouring poles, so this field can be regarded as the sinusoidal magnetic field. This article mainly discusses the influence of the closed flux region on the levitation performance of the bulk high-temperature superconductor (HTS). Moreover, the levitation performance is compared between the closed and diverging region of magnetic flux. The experimental results can be analyzed by the magnetic circuit theory and the frozen-image model. The analysis indicates that the closed region of magnetic flux can influence the levitation performance of bulk HTS obviously and provide an extra useful guidance force. These conclusions are helpful to optimize the HTS Maglev system.

THE RESONANT OVERVOLTAGE IN NON-SINUSOIDAL MODE OF MAIN ELECTRIC NETWORK

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V. G. Kuznetsov

2018-04-01

Full Text Available Purpose. The resonant overvoltage arises in main electrical networks as a result of random coincidence of some parameters of circuit and its mode and it may exist for a relatively long time. Therefore, the traditional means of limitation of short duration commutation surges are not effective in this case. The study determines conditions of appearance and development of non-sinusoidal mode after switching idle autotransformer to the overhead line of extra high voltage. The purpose of the paper is to choice measures for prevention overvoltage, too. Methodology. The study has used the result of extra high voltage line testing, the methods of electric circuit theory and the simulation in the MATLAB & Simulink package. Results. The simulation model of the extra high voltage transmission line for the study of resonant non-sinusoidal overvoltage is developed. The conditions for the appearance of resonant circuits in the real power line are found and harmonic frequency in which overvoltage arises are obtained. The study proposes using the controlled switching device as a measure to prevent resonance surges and determines the appropriate settings. Originality. The expression for calculation of resonant length of extra high voltage line was derived. The special investigation of processes in the resonant circuit of the extra high voltage transmission line for higher harmonic components of voltage is carried out. The program of switching for control apparatus that prevents non-sinusoidal overvoltage has been developed at the first time. Practical value. The using of the proposed settings of controlled switchgear will prevent the occurrence of hazardous resonant surge on higher harmonic components of voltage.

Predicting the mixed-mode I/II spatial damage propagation along 3D-printed soft interfacial layer via a hyperelastic softening model

Science.gov (United States)

Liu, Lei; Li, Yaning

2018-07-01

A methodology was developed to use a hyperelastic softening model to predict the constitutive behavior and the spatial damage propagation of nonlinear materials with damage-induced softening under mixed-mode loading. A user subroutine (ABAQUS/VUMAT) was developed for numerical implementation of the model. 3D-printed wavy soft rubbery interfacial layer was used as a material system to verify and validate the methodology. The Arruda - Boyce hyperelastic model is incorporated with the softening model to capture the nonlinear pre-and post- damage behavior of the interfacial layer under mixed Mode I/II loads. To characterize model parameters of the 3D-printed rubbery interfacial layer, a series of scarf-joint specimens were designed, which enabled systematic variation of stress triaxiality via a single geometric parameter, the slant angle. It was found that the important model parameter m is exponentially related to the stress triaxiality. Compact tension specimens of the sinusoidal wavy interfacial layer with different waviness were designed and fabricated via multi-material 3D printing. Finite element (FE) simulations were conducted to predict the spatial damage propagation of the material within the wavy interfacial layer. Compact tension experiments were performed to verify the model prediction. The results show that the model developed is able to accurately predict the damage propagation of the 3D-printed rubbery interfacial layer under complicated stress-state without pre-defined failure criteria.

Ageing monitoring in IGBT module under sinusoidal loading

DEFF Research Database (Denmark)

Ghimire, Pramod; Pedersen, Kristian Bonderup; Rannestad, Bjørn

2015-01-01

This paper presents monitoring of ageing in high power insulated gate bipolar transistor (IGBT) modules subjected to sinusoidal loading at nominal power level. On-state voltage for IGBT, diode, and rise in interconnection resistance are used as ageing parameters. These are measured in three...... different ways: calibration of power modules after 24 h of operation, offline characterization every 5 min of operation, and continuous measurement during normal converter operation. Four power modules are tested, which are cycled to different degradation levels by number of cycles, where one is tested...

Hydraulic testing in granite using the sinusoidal variation of pressure

International Nuclear Information System (INIS)

Black, J.H.; Holmes, D.C.; Noy, D.J.

1982-09-01

Access to two boreholes at the Carwynnen test site in Cornwall enabled the trial of a number of innovative approaches to the hydrogeology of fractured crystalline rock. These methods ranged from the use of seisviewer data to measure the orientation of fractures to the use of the sinusoidal pressure technique to measure directional hydraulic diffusivity. The testing began with a short programme of site investigation consisting of borehole caliper and seisviewer logging followed by some single borehole hydraulic tests. The single borehole hydraulic testing was designed to assess whether the available boreholes and adjacent rock were suitable for testing using the sinusoidal method. The main testing methods were slug and pulse tests and were analysed using the fissured porous medium analysis proposed in Barker and Black (1983). Derived hydraulic conductivity (K) ranged from 2 x 10 -12 m/sec to 5 x 10 -7 m/sec with one near-surface zone of high K being perceived in both boreholes. The results were of the form which is typical of fractured rock and indicated a combination of high fracture frequency and permeable granite matrix. The results are described and discussed. (author)

Calculation of the mean path length of the Epstein frame under non-sinusoidal excitations using the double Epstein method

International Nuclear Information System (INIS)

Marketos, Philip; Zurek, Stan; Moses, Anthony J.

2008-01-01

This paper discusses the effect of non-sinusoidal excitation on the mean path length of the Epstein frame. Two different steels, a non-oriented (NO) steel and a high-permeability grain-oriented (HGO) electrical steel have been tested under pure sinusoidal and non-sinusoidal excitations and the mean path length of the Epstein frame has been re-calculated. Results indicate that the actual mean path of the Epstein frame depends not only on the material permeability and anisotropy but also on the peak flux density and magnetising frequency. The amount of distortion of the excitation frequency also has an effect on the value of the actual mean path length of the Epstein frame

Research on a new magnetic-field-modulated brushless double-rotor machine with sinusoidal-permeance modulating ring

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Ping Zheng

2017-05-01

Full Text Available The magnetic-field-modulated brushless double-rotor machine (MFM-BDRM, composed of a stator, a modulating ring rotor, and a PM rotor, is a kind of power-split device for hybrid electric vehicles (HEVs. In this paper, a new MFM-BDRM with sinusoidal-permeance modulating ring named Sinusoidal-Permeance-Modulating-Ring Brushless Double-Rotor Machine (SPMR-BDRM is proposed to solve the problem of poor mechanical strength and large iron loss. The structure and the operating principle of the MFM-BDRM are introduced. The design principle of the sinusoidal-permeance modulating ring is analyzed and derived. The main idea of that is to minimize the harmonic permeance of air gap, thereby the harmonic magnetic fields can be restrained. There are comparisons between a MFM-BDRM with sinusoidal-permeance modulating ring and a same size MFM-BDRM with traditional modulating ring, including magnetic field distributions and electromagnetic performances. Most importantly, the iron losses are compared under six different conditions. The result indicates that the harmonic magnetic fields in the air gap are restrained; the electromagnetic torque and power factor are almost the same with same armature current; the torque ripples of the modulating ring rotor and the PM rotor are reduced; the stator loss is reduced by 13% at least and the PM loss is reduced by 20% at least compared with the same size traditional MFM-BDRM under the same operating conditions.

Sinusoidal Obstruction Syndrome (Hepatic Veno-Occlusive Disease)

Science.gov (United States)

Fan, Cathy Q.; Crawford, James M.

2014-01-01

Hepatic sinusoidal obstruction syndrome (SOS) is an obliterative venulitis of the terminal hepatic venules, which in its more severe forms imparts a high risk of mortality. SOS, also known as veno-occlusive disease (VOD), occurs as a result of cytoreductive therapy prior to hematopoietic stem cell transplantation (HSCT), following oxaliplatin-containing adjuvant or neoadjuvant chemotherapy for colorectal carcinoma metastatic to the liver and treated by partial hepatectomy, in patients taking pyrrolizidine alkaloid-containing herbal remedies, and in other particular settings such as the autosomal recessive condition of veno-occlusive disease with immunodeficiency (VODI). A central pathogenic event is toxic destruction of hepatic sinusoidal endothelial cells (SEC), with sloughing and downstream occlusion of terminal hepatic venules. Contributing factors are SEC glutathione depletion, nitric oxide depletion, increased intrahepatic expression of matrix metalloproteinases and vascular endothelial growth factor (VEGF), and activation of clotting factors. The clinical presentation of SOS includes jaundice, development of right upper-quadrant pain and tender hepatomegaly, ascites, and unexplained weight gain. Owing to the potentially critical condition of these patients, transjugular biopsy may be the preferred route for liver biopsy to exclude other potential causes of liver dysfunction and to establish a diagnosis of SOS. Treatment includes rigorous fluid management so as to avoid excessive fluid overload while avoiding too rapid diuresis or pericentesis, potential use of pharmaceutics such as defibrotide, coagulolytic agents, or methylprednisolone, and liver transplantation. Proposed strategies for prevention and prophylaxis include reduced-intensity conditioning radiation for HSCT, treatment with ursodeoxycholic acid, and inclusion of bevacizumab with oxaliplatin-based chemotherapeutic regimes. While significant progress has been made in understanding the pathogenesis

Observation of Sinusoidal Voltage Behaviour in Silver Doped YBCO

Science.gov (United States)

Altinkok, Atilgan; Olutas, Murat; Kilic, Kivilcim; Kilic, Atilla

The influence of bi-directional square wave (BSW) current was investigated on the evolution of the V - t curves at different periods (P) , temperatures and external magnetic fields. It was observed that slow transport relaxation measurements result in regular sinusoidal voltage oscillations which were discussed mainly in terms of the dynamic competition between pinning and depinning.The symmetry in the voltage oscillations was attributed to the elastic coupling between the flux lines and the pinning centers along grain boundaries and partly inside the grains. This case was also correlated to the equality between flux entry and exit along the YBCO/Ag sample during regular oscillations. It was shown that the voltage oscillations can be described well by an empirical expression V (t) sin(wt + φ) . We found that the phase angle φgenerally takes different values for the repetitive oscillations. Fast Fourier Transform analysis of the V - t oscillations showed that the oscillation period is comparable to that (PI) of the BSW current. This finding suggests a physical mechanism associated with charge density waves (CDWs), and, indeed, the weakly pinned flux line system in YBCO/Ag resembles the general behavior of CDWs. At certain values of PI, amplitude of BSW current, H and T, the YBCO/Ag sample behaves like a double-integrator, since it converts the BSW current to sinusoidal voltage oscillations in time.

Scavenger receptor-mediated endocytosis by sinusoidal cells in rat bone marrow

International Nuclear Information System (INIS)

Geoffroy, J.S.

1987-01-01

Endocytosis of serum albumin by sinusoidal endothelial cells in rat bone marrow was investigated initially at the ultrastructural level with subsequent biochemical investigation of the specificity mediating this event. Bovine serum albumin adsorbed to 20nm colloidal gold particles (AuBSA) was chosen as the electron microscopic probe. Morphological data strongly suggested that a receptor was involved in uptake of AuBSA. Confirmation of receptor involvement in the uptake of AuBSA by marrow sinusoidal endothelial cells was achieved utilizing an in situ isolated hind limb perfusion protocol in conjunction with unlabeled, radiolabeled, and radio-/colloidal gold labeled probes. The major findings of competition and saturation experiments were: (1) endocytosis of AuBSA was mediated by a receptor for modified/treated serum albumin; (2) endocytosis of formaldehyde-treated serum albumin was mediated by a binding site which may be the same or closely related to the site responsible for the uptake of AuBSA; and (3) endocytosis of native untreated albumin was not mediated by receptor and probably represents fluid-phase pinocitosis

Modeling and Simulation of MIMO Mobile-to-Mobile Wireless Fading Channels

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Gholamreza Bakhshi

2012-01-01

Full Text Available Analysis and design of multielement antenna systems in mobile fading channels require a model for the space-time cross-correlation among the links of the underlying multipleinput multiple-output (MIMO Mobile-to-Mobile (M-to-M communication channels. In this paper, we propose the modified geometrical two-ring model, a MIMO channel reference model for M-to-M communication systems. This model is based on the extension of single-bounce two-ring scattering model for flat fading channel under the assumption that the transmitter and the receiver are moving. Assuming single-bounce scattering model in both isotropic and nonisotropic environment, a closed-form expression for the space-time cross-correlation function (CCF between any two subchannels is derived. The proposed model provides an important framework in M-to-M system design, where includes many existing correlation models as special cases. Also, two realizable statistical simulation models are proposed for simulating both isotropic and nonisotropic reference model. The realizable simulation models are based on Sum-of-Sinusoids (SoS simulation model. Finally, the correctness of the proposed simulation models is shown via different simulation scenarios.

Iron Losses in Electrical Machines Due to Non Sinusoidal Alternating Fluxes

DEFF Research Database (Denmark)

Ritchie, Ewen; Walker, J.A.; Dorrell, D. G.

2007-01-01

This paper shows how the flux waveform in the core of an electrical machine can be vary non- sinusoidally which complicates the calculation of the iron loss in a machine. A set of tests are conducted on a steel sample using an Epstein square where harmonics are injected into the flux waveform which...... of a machine....

Numerical analysis of beam with sinusoidally corrugated webs

Science.gov (United States)

Górecki, Marcin; Pieńko, Michał; Łagoda, GraŻyna

2018-01-01

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

Effect of back-pressure forcing on shock train structures in rectangular channels

Science.gov (United States)

Gnani, F.; Zare-Behtash, H.; White, C.; Kontis, K.

2018-04-01

The deceleration of a supersonic flow to the subsonic regime inside a high-speed engine occurs through a series of shock waves, known as a shock train. The generation of such a flow structure is due to the interaction between the shock waves and the boundary layer inside a long and narrow duct. The understanding of the physics governing the shock train is vital for the improvement of the design of high-speed engines and the development of flow control strategies. The present paper analyses the sensitivity of the shock train configuration to a back-pressure variation. The complex characteristics of the shock train at an inflow Mach number M = 2 in a channel of constant height are investigated with two-dimensional RANS equations closed by the Wilcox k-ω turbulence model. Under a sinusoidal back-pressure variation, the simulated results indicate that the shock train executes a motion around its mean position that deviates from a perfect sinusoidal profile with variation in oscillation amplitude, frequency, and whether the pressure is first increased or decreased.

Compact broadband polarization beam splitter using a symmetric directional coupler with sinusoidal bends.

Science.gov (United States)

Zhang, Fan; Yun, Han; Wang, Yun; Lu, Zeqin; Chrostowski, Lukas; Jaeger, Nicolas A F

2017-01-15

We design and demonstrate a compact broadband polarization beam splitter (PBS) using a symmetric directional coupler with sinusoidal bends on a silicon-on-insulator platform. The sinusoidal bends in our PBS suppress the power exchange between two parallel symmetric strip waveguides for the transverse-electric (TE) mode, while allowing for the maximum power transfer to the adjacent waveguide for the transverse-magnetic (TM) mode. Our PBS has a nominal coupler length of 8.55 μm, and it has an average extinction ratio (ER) of 12.0 dB for the TE mode, an average ER of 20.1 dB for the TM mode, an average polarization isolation (PI) of 20.6 dB for the through port, and an average PI of 11.5 dB for the cross port, all over a bandwidth of 100 nm.

CMOS-based active RC sinusoidal oscillator with four-phase quadrature outputs and single-resistance-controlled (SRC) tuning laws

OpenAIRE

Lahiri, Abhirup; Herencsár, Norbert

2012-01-01

This paper proposes a very compact CMOS realization of active RC sinusoidal oscillator capable of generating four quadrature voltage outputs. The oscillator is based on the cascade of lossless and lossy integrators in loop. The governing laws for the condition of oscillation (CO) and the frequency of oscillation (FO) are single-resistance-controlled (SRC) and which allow independent FO tuning. Unlike previously reported SRC-based sinusoidal oscillators based on the active building block (ABB)...

Propiedades de transporte de una superred de grafeno tipo sinusoidal

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J. A. Briones-Torres

2015-01-01

Full Text Available En este trabajo usamos el método de la matriz de transferencia para estudiar el tunelamiento de los electrones de Dirac a través de superredes en grafeno. Consideramos una superred con potencial sinusoidal o polaridad invertida, para ello consideramos dos maneras de crearla, una por medio de sustratos mixtos junto con la aplicación de un campo perpendicular sobre el sustrato de Óxido de Silicio (SiO2, la otra por medio de potenciales alternados aplicados perpendicularmente sobre la sábana de grafeno. Calculamos las propiedades de transmisión, transporte y estructura electrónica, variando diferentes parámetros como ángulo de incidencia, anchos de pozos y barreras y diferente número de barreras. Se encontró (1 el importante papel que juega el efecto Klein en tales estructuras, (2 las propiedades de transmisión y transporte presentan cierta simetría respecto del origen de la energía, y (3 el carácter sinusoidal del sistema trae consigo una baja en el nivel de energía de las subbandas en el espectro de estados acotados, además las degenera y origina que la apertura-cierre de las minibandas sea en el mismo nivel de energía.

Galvanically Decoupled Current Source Modules for Multi-Channel Bioimpedance Measurement Systems

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Roman Kusche

2017-10-01

Full Text Available Bioimpedance measurements have become a useful technique in the past several years in biomedical engineering. Especially, multi-channel measurements facilitate new imaging and patient monitoring techniques. While most instrumentation research has focused on signal acquisition and signal processing, this work proposes the design of an excitation current source module that can be easily implemented in existing or upcoming bioimpedance measurement systems. It is galvanically isolated to enable simultaneous multi-channel bioimpedance measurements with a very low channel-coupling. The system is based on a microcontroller in combination with a voltage-controlled current source circuit. It generates selectable sinusoidal excitation signals between 0.12 and 1.5 mA in a frequency range from 12 to 250 kHz, whereas the voltage compliance range is ±3.2 V. The coupling factor between two current sources, experimentally galvanically connected with each other, is measured to be less than −48 dB over the entire intended frequency range. Finally, suggestions for developments in the future are made.

Galalctic Tides & the Sinusoidal Potential

Science.gov (United States)

Bartlett, David F.

2011-05-01

The sinusoidal potential is a nonNewtonian alternative to dark matter. Instead of φ = -GM/r we write φ = -(GM/r) cos kor, where ko= 2π/ λo and λo = Ro/20= 400 pc. Evidence for this choice for the "wavelength” λo has been given in one article and many previous meetings of the AAS & DDA. The solar system and nearby stars are trapped in a local groove of width Δr Quality (4 types) and semi-major axis aoriginal . For 10 of the 12 classes radial tides dominate Z-tides. The classic Oort cloud comets (1851-1996) have a particularly strong modulation with galactic longitude. This modulation is exactly in those directions where a radial tide would be important. The equally numerous recent Oort comets (1996-2008) show a different evidence for strong radial tides. The recent comets generally have much larger perihelion distances q than the classic ones. Here the evidence is that a radial tide is removing angular momentum from the orbit and thus bringing the perihelion closer to the earth and to observers.

Highly enhanced avalanche probability using sinusoidally-gated silicon avalanche photodiode

Energy Technology Data Exchange (ETDEWEB)

Suzuki, Shingo; Namekata, Naoto, E-mail: nnao@phys.cst.nihon-u.ac.jp; Inoue, Shuichiro [Institute of Quantum Science, Nihon University, 1-8-14 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan); Tsujino, Kenji [Tokyo Women' s Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666 (Japan)

2014-01-27

We report on visible light single photon detection using a sinusoidally-gated silicon avalanche photodiode. Detection efficiency of 70.6% was achieved at a wavelength of 520 nm when an electrically cooled silicon avalanche photodiode with a quantum efficiency of 72.4% was used, which implies that a photo-excited single charge carrier in a silicon avalanche photodiode can trigger a detectable avalanche (charge) signal with a probability of 97.6%.

LES of stratified-wavy flows using novel near-interface treatment

Science.gov (United States)

Karnik, Aditya; Kahouadji, Lyes; Chergui, Jalel; Juric, Damir; Shin, Seungwon; Matar, Omar K.

2017-11-01

The pressure drop in horizontal stratified wavy flows is influenced by interfacial shear stress. The near-interface behavior of the lighter phase is akin to that near a moving wall. We employ a front-tracking code, Blue, to simulate and capture the near-interface behaviour of both phases. Blue uses a modified Smagorinsky LES model incorporating a novel near-interface treatment for the sub-grid viscosity, which is influenced by damping due to the wall-like interface, and enhancement of the turbulent kinetic energy (TKE) due to the interfacial waves. Simulations are carried out for both air-water and oil-water stratified configurations to demonstrate the applicability of the present method. The mean velocities and tangential Reynolds stresses are compared with experiments for both configurations. At the higher Re, the waves penetrate well into the buffer region of the boundary layer above the interface thus altering its dynamics. Previous attempts to capture the secondary structures associated with such flows using RANS or standard LES methodologies have been unsuccessful. The ability of the present method to reproduce these structures is due to the correct estimation of the near-interface TKE governing energy transfer from the normal to tangential directions. EPSRC, UK, MEMPHIS program Grant (EP/K003976/1), RAEng Research Chair (OKM).

Representative Sinusoids for Hepatic Four-Scale Pharmacokinetics Simulations.

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Lars Ole Schwen

Full Text Available The mammalian liver plays a key role for metabolism and detoxification of xenobiotics in the body. The corresponding biochemical processes are typically subject to spatial variations at different length scales. Zonal enzyme expression along sinusoids leads to zonated metabolization already in the healthy state. Pathological states of the liver may involve liver cells affected in a zonated manner or heterogeneously across the whole organ. This spatial heterogeneity, however, cannot be described by most computational models which usually consider the liver as a homogeneous, well-stirred organ. The goal of this article is to present a methodology to extend whole-body pharmacokinetics models by a detailed liver model, combining different modeling approaches from the literature. This approach results in an integrated four-scale model, from single cells via sinusoids and the organ to the whole organism, capable of mechanistically representing metabolization inhomogeneity in livers at different spatial scales. Moreover, the model shows circulatory mixing effects due to a delayed recirculation through the surrounding organism. To show that this approach is generally applicable for different physiological processes, we show three applications as proofs of concept, covering a range of species, compounds, and diseased states: clearance of midazolam in steatotic human livers, clearance of caffeine in mouse livers regenerating from necrosis, and a parameter study on the impact of different cell entities on insulin uptake in mouse livers. The examples illustrate how variations only discernible at the local scale influence substance distribution in the plasma at the whole-body level. In particular, our results show that simultaneously considering variations at all relevant spatial scales may be necessary to understand their impact on observations at the organism scale.

Plasma characteristics in non-sinusoidally excited CCP discharges

Science.gov (United States)

Lafleur, Trevor; Booth, Jean-Paul

2012-10-01

Using particle-in-cell (PIC) simulations we perform a characterization of the plasma response to positive pulse-type voltage excitations (with a repetition frequency of 13.56 MHz) in a geometrically symmetric CCP reactor (with a gap length of 2 cm) operated with argon (for pressures between 20-500 mTorr). Use of these non-sinusoidal waveforms generates an electrical asymmetry effect in the system, which necessitates the formation of a DC bias. This DC bias, together with the shape of the voltage waveforms used, produces a number of new phenomena that are not present in typical sinusoidal discharges: (1) the plasma density and ion flux can be increased as the pulse width is reduced, (2) a significant asymmetry in the ion fluxes to the powered and grounded electrodes develops as the pressure increases, (3) the average ion energy striking the grounded electrode remains low and approximately constant as the pulse width decreases, and (4) the sheath at the grounded electrode never fully collapses; electrons are no longer lost in sharp pulses, but escape essentially throughout the rf cycle. Effects (1) and (3) above offer the possibility for a new form of control in these types of discharges, where the ion flux can be increased while the ion energy on the grounded electrode can be kept small and essentially constant. This effect has recently been exploited to control the crystallinity of silicon thin films [1], where the low ion bombarding energy was found to improve the quality of films grown. [4pt] [1] Johnson E V, Pouliquen S, Delattre P A, and Booth J P, J. Non-Cryst. Solids 2012, in press.

Influence of the Periodicity of Sinusoidal Boundary Condition on the Unsteady Mixed Convection within a Square Enclosure Using an Ag–Water Nanofluid

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Azharul Karim

2017-12-01

Full Text Available A numerical study of the unsteady mixed convection heat transfer characteristics of an Ag–water nanofluid confined within a square shape lid-driven cavity has been carried out. The Galerkin weighted residual of the finite element method has been employed to investigate the effects of the periodicity of sinusoidal boundary condition for a wide range of Grashof numbers (Gr (105 to 107 with the parametric variation of sinusoidal even and odd frequency, N, from 1 to 6 at different instants (for τ = 0.1 and 1. It has been observed that both the Grashof number and the sinusoidal even and odd frequency have a significant influence on the streamlines and isotherms inside the cavity. The heat transfer rate enhanced by 90% from the heated surface as the Grashof number (Gr increased from 105 to 107 at sinusoidal frequency N = 1 and τ = 1.

Automatic fringe enhancement with novel bidimensional sinusoids-assisted empirical mode decomposition.

Science.gov (United States)

Wang, Chenxing; Kemao, Qian; Da, Feipeng

2017-10-02

Fringe-based optical measurement techniques require reliable fringe analysis methods, where empirical mode decomposition (EMD) is an outstanding one due to its ability of analyzing complex signals and the merit of being data-driven. However, two challenging issues hinder the application of EMD in practical measurement. One is the tricky mode mixing problem (MMP), making the decomposed intrinsic mode functions (IMFs) have equivocal physical meaning; the other is the automatic and accurate extraction of the sinusoidal fringe from the IMFs when unpredictable and unavoidable background and noise exist in real measurements. Accordingly, in this paper, a novel bidimensional sinusoids-assisted EMD (BSEMD) is proposed to decompose a fringe pattern into mono-component bidimensional IMFs (BIMFs), with the MMP solved; properties of the resulted BIMFs are then analyzed to recognize and enhance the useful fringe component. The decomposition and the fringe recognition are integrated and the latter provides a feedback to the former, helping to automatically stop the decomposition to make the algorithm simpler and more reliable. A series of experiments show that the proposed method is accurate, efficient and robust to various fringe patterns even with poor quality, rendering it a potential tool for practical use.

Electrohydrodynamic channeling effects in narrow fractures and pores

Science.gov (United States)

Bolet, Asger; Linga, Gaute; Mathiesen, Joachim

2018-04-01

In low-permeability rock, fluid and mineral transport occur in pores and fracture apertures at the scale of micrometers and below. At this scale, the presence of surface charge, and a resultant electrical double layer, may considerably alter transport properties. However, due to the inherent nonlinearity of the governing equations, numerical and theoretical studies of the coupling between electric double layers and flow have mostly been limited to two-dimensional or axisymmetric geometries. Here, we present comprehensive three-dimensional simulations of electrohydrodynamic flow in an idealized fracture geometry consisting of a sinusoidally undulated bottom surface and a flat top surface. We investigate the effects of varying the amplitude and the Debye length (relative to the fracture aperture) and quantify their impact on flow channeling. The results indicate that channeling can be significantly increased in the plane of flow. Local flow in the narrow regions can be slowed down by up to 5 % compared to the same geometry without charge, for the highest amplitude considered. This indicates that electrohydrodynamics may have consequences for transport phenomena and surface growth in geophysical systems.

Predicting the onset of nucleate boiling in wavy free-falling turbulent liquid films

Energy Technology Data Exchange (ETDEWEB)

Marsh, W J; Mudawar, I [Purdue Univ., Lafayette, IN (USA). School of Mechanical Engineering

1989-02-01

Experiments are performed to develop a fundamental understanding of boiling incipience in wavy free-falling turbulent liquid films. Incipience conditions are measured and correlated for water and a fluorocarbon (FC-72) liquid. Incipience in water films is influenced by turbulent eddies and, to a larger extent, by interfacial waves. A new approach to predicting incipience in water and other non-wetting fluids is presented. This approach utilizes physical parameters of commonly accepted incipience models and provides a means of correcting these models for the effects of turbulent eddies and roll waves. This study also demonstrates some unique incipience characteristics of fluorocarbon films. The weak surface tension forces of FC-72 allow droplets and liquid streams to break of the crests of incoming roll waves prior to, and during nucleate boiling. The low contact angle of FC-72 allows the liquid to penetrate deep inside wall cavities. Thus incipience from these flooded cavities requires much higher wall superheat than predicted from incipience models. (author).

Predicting the onset of nucleate boiling in wavy free-falling turbulent liquid films

International Nuclear Information System (INIS)

Marsh, W.J.; Mudawar, I.

1989-01-01

Experiments are performed to develop a fundamental understanding of boiling incipience in wavy free-falling turbulent liquid films. Incipience conditions are measured and correlated for water and a fluorocarbon (FC-72) liquid. Incipience in water films is influenced by turbulent eddies and, to a larger extent, by interfacial waves. A new approach to predicting incipience in water and other non-wetting fluids is presented. This approach utilizes physical parameters of commonly accepted incipience models and provides a means of correcting these models for the effects of turbulent eddies and roll waves. This study also demonstrates some unique incipience characteristics of fluorocarbon films. The weak surface tension forces of FC-72 allow droplets and liquid streams to break of the crests of incoming roll waves prior to, and during nucleate boiling. The low contact angle of FC-72 allows the liquid to penetrate deep inside wall cavities. Thus incipience from these flooded cavities requires much higher wall superheat than predicted from incipience models. (author)

A flexible ligand-based wavy layered metal-organic framework for lithium-ion storage.

Science.gov (United States)

An, Tiance; Wang, Yuhang; Tang, Jing; Wang, Yang; Zhang, Lijuan; Zheng, Gengfeng

2015-05-01

A substantial challenge for direct utilization of metal-organic frameworks (MOFs) as lithium-ion battery anodes is to maintain the rigid MOF structure during lithiation/delithiation cycles. In this work, we developed a flexible, wavy layered nickel-based MOF (C20H24Cl2N8Ni, designated as Ni-Me4bpz) by a solvothermal approach of 3,3',5,5'-tetramethyl-4,4'-bipyrazole (H2Me4bpz) with nickel(II) chloride hexahydrate. The obtained MOF materials (Ni-Me4bpz) with metal azolate coordination mode provide 2-dimensional layered structure for Li(+) intercalation/extraction, and the H2Me4bpz ligands allow for flexible rotation feature and structural stability. Lithium-ion battery anodes made of the Ni-Me4bpz material demonstrate excellent specific capacity and cycling performance, and the crystal structure is well preserved after the electrochemical tests, suggesting the potential of developing flexible layered MOFs for efficient and stable electrochemical storage. Copyright © 2015 Elsevier Inc. All rights reserved.

Design of Helical Capacitance Sensor for Holdup Measurement in Two-Phase Stratified Flow: A Sinusoidal Function Approach

Science.gov (United States)

Lim, Lam Ghai; Pao, William K. S.; Hamid, Nor Hisham; Tang, Tong Boon

2016-01-01

A 360° twisted helical capacitance sensor was developed for holdup measurement in horizontal two-phase stratified flow. Instead of suppressing nonlinear response, the sensor was optimized in such a way that a ‘sine-like’ function was displayed on top of the linear function. This concept of design had been implemented and verified in both software and hardware. A good agreement was achieved between the finite element model of proposed design and the approximation model (pure sinusoidal function), with a maximum difference of ±1.2%. In addition, the design parameters of the sensor were analysed and investigated. It was found that the error in symmetry of the sinusoidal function could be minimized by adjusting the pitch of helix. The experiments of air-water and oil-water stratified flows were carried out and validated the sinusoidal relationship with a maximum difference of ±1.2% and ±1.3% for the range of water holdup from 0.15 to 0.85. The proposed design concept therefore may pose a promising alternative for the optimization of capacitance sensor design. PMID:27384567

Design of Helical Capacitance Sensor for Holdup Measurement in Two-Phase Stratified Flow: A Sinusoidal Function Approach

Directory of Open Access Journals (Sweden)

Lam Ghai Lim

2016-07-01

Full Text Available A 360° twisted helical capacitance sensor was developed for holdup measurement in horizontal two-phase stratified flow. Instead of suppressing nonlinear response, the sensor was optimized in such a way that a ‘sine-like’ function was displayed on top of the linear function. This concept of design had been implemented and verified in both software and hardware. A good agreement was achieved between the finite element model of proposed design and the approximation model (pure sinusoidal function, with a maximum difference of ±1.2%. In addition, the design parameters of the sensor were analysed and investigated. It was found that the error in symmetry of the sinusoidal function could be minimized by adjusting the pitch of helix. The experiments of air-water and oil-water stratified flows were carried out and validated the sinusoidal relationship with a maximum difference of ±1.2% and ±1.3% for the range of water holdup from 0.15 to 0.85. The proposed design concept therefore may pose a promising alternative for the optimization of capacitance sensor design.

Design of Helical Capacitance Sensor for Holdup Measurement in Two-Phase Stratified Flow: A Sinusoidal Function Approach.

Science.gov (United States)

Lim, Lam Ghai; Pao, William K S; Hamid, Nor Hisham; Tang, Tong Boon

2016-07-04

A 360° twisted helical capacitance sensor was developed for holdup measurement in horizontal two-phase stratified flow. Instead of suppressing nonlinear response, the sensor was optimized in such a way that a 'sine-like' function was displayed on top of the linear function. This concept of design had been implemented and verified in both software and hardware. A good agreement was achieved between the finite element model of proposed design and the approximation model (pure sinusoidal function), with a maximum difference of ±1.2%. In addition, the design parameters of the sensor were analysed and investigated. It was found that the error in symmetry of the sinusoidal function could be minimized by adjusting the pitch of helix. The experiments of air-water and oil-water stratified flows were carried out and validated the sinusoidal relationship with a maximum difference of ±1.2% and ±1.3% for the range of water holdup from 0.15 to 0.85. The proposed design concept therefore may pose a promising alternative for the optimization of capacitance sensor design.

Nature of Time as the Wavy-like Motion of the Matter Based on the ``Substantial Motion'' Theory of Iranian Philosopher; Mulla Sadra

Science.gov (United States)

Gholibeigian, Hassan; Amirshahkarami, Abdolazim; Gholibeigian, Kazem

2016-03-01

In Sadra's theory, the time for an atom (body) becomes momentums of its involved fundamental particles (strings), (time's relativity) [Gholibeigian, APS March Meeting 2015, abstract #V1.023]. Einstein's theory of special relativity can be special form of Sadra's theory. ``The nature has two magnitudes and two elongations, the one is gradual being (wavy-like motion) which belongs to the time and dividable to the former and the next times in mind, and the other is jerky-like motion which belongs to the space and dividable to the former and the next places' [Asfar, Mulla Sadra, (1571/2-1640)]. Sadra separated the nature of time from nature of space. Therefore we can match these two natures on wave-particle duality. It means that the nature of time can be wavy-like and the nature of space can be jerky-like. So, there are two independent variable sources for particle(s)' flow with respect of its two natures such as potential of flow and relative time which vary with respect of both space and time. Consequently we propose two additional parts to Schrodinger's equation: HΨ + ∇t' = EΨ + ∂t' / ∂t , where t is time and t' is relative time: t' = t +/- Δt . AmirKabir University of Technology, Tehran, Iran.

[Defibrotide therapy for patients with sinusoidal obstruction syndrome after hematopoietic stem cell transplantation].

Science.gov (United States)

Yakushijin, Kimikazu; Okamura, Atsuo; Ono, Kanako; Kawano, Yuko; Kawano, Hiroki; Funakoshi, Yohei; Kawamori, Yuriko; Nishikawa, Shinichiro; Minagawa, Kentaro; Sada, Akiko; Shimoyama, Manabu; Yamamoto, Katsuya; Katayama, Yoshio; Matsui, Toshimitsu

2009-01-01

Sinusoidal obstruction syndrome (SOS) is one of the life-threatening complications caused by endothelial damage to the hepatic sinusoids after hematopoietic stem cell transplantation. However, a satisfactory treatment for SOS has not yet been established. Defibrotide has anti-thrombotic, anti-ischemic, anti-inflammatory, and thrombolytic properties without systemic anticoagulant effects. We treated eight post-transplant SOS patients with defibrotide. Three patients responded to the therapy and the initial response was observed within a week. In addition to the improvement of liver function, rapid recovery of response to diuretic drugs followed by the improvement of renal function was observed. All of the five patients with respiratory dysfunction died despite administration of defibrotide, suggesting that early treatment might lead to better outcomes. There were no severe adverse effects directly due to defibrotide administration. Defibrotide seems to be a promising treatment for SOS, and the initiation of a clinical study in Japan would be important.

CFD study on NACA 4415 airfoil implementing spherical and sinusoidal Tubercle Leading Edge.

Science.gov (United States)

Aftab, S M A; Ahmad, K A

2017-01-01

The Humpback whale tubercles have been studied for more than a decade. Tubercle Leading Edge (TLE) effectively reduces the separation bubble size and helps in delaying stall. They are very effective in case of low Reynolds number flows. The current Computational Fluid Dynamics (CFD) study is on NACA 4415 airfoil, at a Reynolds number 120,000. Two TLE shapes are tested on NACA 4415 airfoil. The tubercle designs implemented on the airfoil are sinusoidal and spherical. A parametric study is also carried out considering three amplitudes (0.025c, 0.05c and 0.075c), the wavelength (0.25c) is fixed. Structured mesh is utilized to generate grid and Transition SST turbulence model is used to capture the flow physics. Results clearly show spherical tubercles outperform sinusoidal tubercles. Furthermore experimental study considering spherical TLE is carried out at Reynolds number 200,000. The experimental results show that spherical TLE improve performance compared to clean airfoil.

CFD study on NACA 4415 airfoil implementing spherical and sinusoidal Tubercle Leading Edge.

Directory of Open Access Journals (Sweden)

S M A Aftab

Full Text Available The Humpback whale tubercles have been studied for more than a decade. Tubercle Leading Edge (TLE effectively reduces the separation bubble size and helps in delaying stall. They are very effective in case of low Reynolds number flows. The current Computational Fluid Dynamics (CFD study is on NACA 4415 airfoil, at a Reynolds number 120,000. Two TLE shapes are tested on NACA 4415 airfoil. The tubercle designs implemented on the airfoil are sinusoidal and spherical. A parametric study is also carried out considering three amplitudes (0.025c, 0.05c and 0.075c, the wavelength (0.25c is fixed. Structured mesh is utilized to generate grid and Transition SST turbulence model is used to capture the flow physics. Results clearly show spherical tubercles outperform sinusoidal tubercles. Furthermore experimental study considering spherical TLE is carried out at Reynolds number 200,000. The experimental results show that spherical TLE improve performance compared to clean airfoil.

Controlled generation of nonlinear resonances through sinusoidal lattice modes in Bose–Einstein condensate

International Nuclear Information System (INIS)

Das, Priyam; Panigrahi, Prasanta K

2015-01-01

We study Bose–Einstein condensate in the combined presence of time modulated optical lattice and harmonic trap in the mean-field approach. Through the self-similar method, we show the existence of sinusoidal lattice modes in this inhomogeneous system, commensurate with the lattice potential. A significant advantage of this system is wide tunability of the parameters through chirp management. The combined effect of the interaction, harmonic trap and lattice potential leads to the generation of nonlinear resonances, exactly where the matter wave changes its direction. When the harmonic trap is switched off, the BEC undergoes a nonlinear compression for the static optical lattice potential. For better understanding of chirp management and the nature of the sinusoidal excitation, we investigate the energy spectrum of the condensate, which clearly reveals the generation of nonlinear resonances in the appropriate regime. We have also identified a classical dynamical phase transition occurring in the system, where loss of superfluidity takes the superfluid phase to an insulating state. (paper)

Stress singularities in a model of a wood disk under sinusoidal pressure

Science.gov (United States)

Jay A. Johnson; John C. Hermanson; Steven M. Cramer; Charles Amundson

2005-01-01

A thin, solid, circular wood disk, cut from the transverse plane of a tree stem, can be modeled as a cylindrically orthotropic elastic material. It is known that a stress singularity can occur at the center of a cylindrically orthotropic disk subjected to uniform pressure. If a solid cylindrically orthotropic disk is subjected to sinusoidal pressure distributions, then...

On the Effect of Rigid Swept Surface Waves on Turbulent Drag

Science.gov (United States)

Denison, M.; Wilkinson, S. P.; Balakumar, P.

2015-01-01

Passive turbulent drag reduction techniques are of interest as a cost effective means to improve air vehicle fuel consumption. In the past, rigid surface waves slanted at an angle from the streamwise direction were deemed ineffective to reduce skin friction drag due to the pressure drag that they generate. A recent analysis seeking similarities to the spanwise shear stress generated by spatial Stokes layers suggested that there may be a range of wavelength, amplitude, and orientation in which the wavy surface would reduce turbulent drag. The present work explores, by experiments and Direct Numerical Simulations (DNS), the effect of swept wavy surfaces on skin friction and pressure drag. Plates with shallow and deep wave patterns were rapid-prototyped and tested using a drag balance in the 7x11 inch Low-Speed Wind Tunnel at the NASA LaRC Research Center. The measured drag o set between the wavy plates and the reference at plate is found to be within the experimental repeatability limit. Oil vapor flow measurements indicate a mean spanwise flow over the deep waves. The turbulent flow in channels with at walls, swept wavy walls and spatial Stokes spanwise velocity forcing was simulated at a friction Reynolds number of two hundred. The time-averaged and dynamic turbulent flow characteristics of the three channel types are compared. The drag obtained for the channel with shallow waves is slightly larger than for the at channel, within the range of the experiments. In the case of the large waves, the simulation over predicts the drag. The shortcomings of the Stokes layer analogy model for the estimation of the spanwise shear stress and drag are discussed.

Losses analysis of soft magnetic ring core under sinusoidal pulse width modulation (SPWM) and space vector pulse width modulation (SVPWM) excitations

Science.gov (United States)

Gao, Hezhe; Li, Yongjian; Wang, Shanming; Zhu, Jianguo; Yang, Qingxin; Zhang, Changgeng; Li, Jingsong

2018-05-01

Practical core losses in electrical machines differ significantly from those experimental results using the standardized measurement method, i.e. Epstein Frame method. In order to obtain a better approximation of the losses in an electrical machine, a simulation method considering sinusoidal pulse width modulation (SPWM) and space vector pulse width modulation (SVPWM) waveforms is proposed. The influence of the pulse width modulation (PWM) parameters on the harmonic components in SPWM and SVPWM is discussed by fast Fourier transform (FFT). Three-level SPWM and SVPWM are analyzed and compared both by simulation and experiment. The core losses of several ring samples magnetized by SPWM, SVPWM and sinusoidal alternating current (AC) are obtained. In addition, the temperature rise of the samples under SPWM, sinusoidal excitation are analyzed and compared.

Diffraction Efficiency Testing of Sinusoidal and Blazed Off-Plane Reflection Gratings

Science.gov (United States)

Tutt, James H.; McEntaffer, Randall L.; Marlowe, Hannah; Miles, Drew M.; Peterson, Thomas J.; Deroo, Casey T.; Scholze, Frank; Laubis, Christian

2016-09-01

Reflection gratings in the off-plane mount have the potential to enhance the performance of future high resolution soft X-ray spectrometers. Diffraction efficiency can be optimized through the use of blazed grating facets, achieving high-throughput on one side of zero-order. This paper presents the results from a comparison between a grating with a sinusoidally grooved profile and two gratings that have been blazed. The results show that the blaze does increase throughput to one side of zero-order; however, the total throughput of the sinusoidal gratings is greater than the blazed gratings, suggesting the method of manufacturing the blazed gratings does not produce precise facets. The blazed gratings were also tested in their Littrow and anti-Littrow configurations to quantify diffraction efficiency sensitivity to rotations about the grating normal. Only a small difference in the energy at which efficiency is maximized between the Littrow and anti-Littrow configurations is seen with a small shift in peak efficiency towards higher energies in the anti-Littrow case. This is due to a decrease in the effective blaze angle in the anti-Littrow mounting. This is supported by PCGrate-SX V6.1 modeling carried out for each blazed grating which predicts similar response trends in the Littrow and anti-Littrow orientations.

Morphodynamics structures induced by variations of the channel width

Science.gov (United States)

Duro, Gonzalo; Crosato, Alessandra; Tassi, Pablo

2014-05-01

In alluvial channels, forcing effects, such as a longitudinally varying width, can induce the formation of steady bars (Olesen, 1984). The type of bars that form, such as alternate, central or multiple, will mainly depend on the local flow width-to-depth ratio and on upstream conditions (Struiksma et al., 1985). The effects on bar formation of varying the channel width received attention only recently and investigations, based on flume experiments and mathematical modelling, are mostly restricted to small longitudinal sinusoidal variations of the channel width (e.g. Repetto et al., 2002; Wu and Yeh, 2005, Zolezzi et al., 2012; Frascati and Lanzoni, 2013). In this work, we analyze the variations in equilibrium bed topography in a longitudinal width-varying channel with characteristic scales of the Waal River (The Netherlands) using two different 2D depth-averaged morphodynamic models, one based on the Delft3D code and one on Telemac-Mascaret system. In particular, we explore the effects of changing the wavelength of sinusoidal width variations in a straight channel, focusing on the effects of the spatial lag between bar formation and forcing that is observed in numerical models and laboratory experiments (e.g. Crosato et al, 2011). We extend the investigations to finite width variations in which longitudinal changes of the width-to-depth ratio are such that they may affect the type of bars that become unstable (alternate, central or multiple bars). Numerical results are qualitatively validated with field observations and the resulting morphodynamic pattern is compared with the physics-based predictor of river bar modes by Crosato and Mosselman (2009). The numerical models are finally used to analyse the experimental conditions of Wu and Yeh (2005). The study should be seen as merely exploratory. The aim is to investigate possible approaches for future research aiming at assessing the effects of artificial river widening and narrowing to control bar formation in

Driving and control strategies in alternative current machines of permanent magnet with non-sinusoidal flux; Estrategias de acionamento e controle em maquinas CA de ima permanente com fluxo nao senoidal

Energy Technology Data Exchange (ETDEWEB)

Monteiro, Jose Roberto Boffino de Almeida

1997-07-01

The aim of this work is to study and analyze the torque performance of brush less machines with non-sinusoidal distributed magnetic fluxes. The machine type considered is a surface mount permanent magnet brush less machine. Three mathematical models for the machine are considered: the per stator phase, the vectorial and the linear second order speed-voltage models. Machines with different stator windings are compared including the permanent magnet synchronous machines with sinusoidal distributed stator windings. The torque outputs of these machines are obtained considering two kinds of open loop driving systems: one with a six-pulse waveform and other with a sinusoidal waveform. Finally, a vectorial control is proposed for the non-sinusoidal machines. The torque ripple as well the overall performance of non-sinusoidal machines with vectorial control is compared to that of sinusoidal machines. (author)

Realization of Electronically Tunable Current- Mode Multiphase Sinusoidal Oscillators Using CFTAs

OpenAIRE

Prungsak Uttaphut

2012-01-01

An implementation of current-mode multiphase sinusoidal oscillators is presented. Using CFTA-based lossy integrators, odd and odd/even phase systems can be realized with following advantages. The condition of oscillation and frequency of oscillation can be orthogonally tuned. The high output impedances facilitate easy driving an external load without additional current buffers. The proposed MSOs provide odd or even phase signals that are equally spaced in phase and equal amplitude. The circui...

Propiedades de transporte de una superred de grafeno tipo sinusoidal

OpenAIRE

J. A. Briones-Torres; I. Rodríguez-Vargas

2015-01-01

En este trabajo usamos el método de la matriz de transferencia para estudiar el tunelamiento de los electrones de Dirac a través de superredes en grafeno. Consideramos una superred con potencial sinusoidal o polaridad invertida, para ello consideramos dos maneras de crearla, una por medio de sustratos mixtos junto con la aplicación de un campo perpendicular sobre el sustrato de Óxido de Silicio (SiO2), la otra por medio de potenciales alternados aplicados perpendicularmente sobre la sábana de...

Slug flow transitions in horizontal gas/liquid two-phase flows. Dependence on channel height and system pressure for air/water and steam/water two-phase flows

International Nuclear Information System (INIS)

Nakamura, Hideo

1996-05-01

The slug flow transitions and related phenomena for horizontal two-phase flows were studied for a better prediction of two-phase flows that typically appear during the reactor loss-of-coolant accidents (LOCAs). For better representation of the flow conditions experimentally, two large-scaled facility: TPTF for high-pressure steam/water two-phase flows and large duct test facility for air/water two-phase flows, were used. The visual observation of the flow using a video-probe was performed in the TPTF experiments for good understanding of the phenomena. The currently-used models and correlations based mostly on the small-scale low-pressure experiments were reviewed and improved based on these experimental results. The modified Taitel-Dukler model for prediction of transition into slug flow from wavy flow and the modified Steen-Wallis correlation for prediction of onset of liquid entrainment from the interfacial waves were obtained. An empirical correlation for the gas-liquid interfacial friction factor was obtained further for prediction of liquid levels at wavy flow. The region of slug flow regime that is generally under influences of the channel height and system pressure was predicted well when these models and correlations were applied together. (author). 90 refs

Binaural unmasking of multi-channel stimuli in bilateral cochlear implant users.

Science.gov (United States)

Van Deun, Lieselot; van Wieringen, Astrid; Francart, Tom; Büchner, Andreas; Lenarz, Thomas; Wouters, Jan

2011-10-01

Previous work suggests that bilateral cochlear implant users are sensitive to interaural cues if experimental speech processors are used to preserve accurate interaural information in the electrical stimulation pattern. Binaural unmasking occurs in adults and children when an interaural delay is applied to the envelope of a high-rate pulse train. Nevertheless, for speech perception, binaural unmasking benefits have not been demonstrated consistently, even with coordinated stimulation at both ears. The present study aimed at bridging the gap between basic psychophysical performance on binaural signal detection tasks on the one hand and binaural perception of speech in noise on the other hand. Therefore, binaural signal detection was expanded to multi-channel stimulation and biologically relevant interaural delays. A harmonic complex, consisting of three sinusoids (125, 250, and 375 Hz), was added to three 125-Hz-wide noise bands centered on the sinusoids. When an interaural delay of 700 μs was introduced, an average BMLD of 3 dB was established. Outcomes are promising in view of real-life benefits. Future research should investigate the generalization of the observed benefits for signal detection to speech perception in everyday listening situations and determine the importance of coordination of bilateral speech processors and accentuation of envelope cues.

Soft Sensing of Non-Newtonian Fluid Flow in Open Venturi Channel Using an Array of Ultrasonic Level Sensors—AI Models and Their Validations

Science.gov (United States)

Viumdal, Håkon; Mylvaganam, Saba

2017-01-01

In oil and gas and geothermal installations, open channels followed by sieves for removal of drill cuttings, are used to monitor the quality and quantity of the drilling fluids. Drilling fluid flow rate is difficult to measure due to the varying flow conditions (e.g., wavy, turbulent and irregular) and the presence of drilling cuttings and gas bubbles. Inclusion of a Venturi section in the open channel and an array of ultrasonic level sensors above it at locations in the vicinity of and above the Venturi constriction gives the varying levels of the drilling fluid in the channel. The time series of the levels from this array of ultrasonic level sensors are used to estimate the drilling fluid flow rate, which is compared with Coriolis meter measurements. Fuzzy logic, neural networks and support vector regression algorithms applied to the data from temporal and spatial ultrasonic level measurements of the drilling fluid in the open channel give estimates of its flow rate with sufficient reliability, repeatability and uncertainty, providing a novel soft sensing of an important process variable. Simulations, cross-validations and experimental results show that feedforward neural networks with the Bayesian regularization learning algorithm provide the best flow rate estimates. Finally, the benefits of using this soft sensing technique combined with Venturi constriction in open channels are discussed. PMID:29072595

Sinusoidal Order Estimation Using Angles between Subspaces

Directory of Open Access Journals (Sweden)

Søren Holdt Jensen

2009-01-01

Full Text Available We consider the problem of determining the order of a parametric model from a noisy signal based on the geometry of the space. More specifically, we do this using the nontrivial angles between the candidate signal subspace model and the noise subspace. The proposed principle is closely related to the subspace orthogonality property known from the MUSIC algorithm, and we study its properties and compare it to other related measures. For the problem of estimating the number of complex sinusoids in white noise, a computationally efficient implementation exists, and this problem is therefore considered in detail. In computer simulations, we compare the proposed method to various well-known methods for order estimation. These show that the proposed method outperforms the other previously published subspace methods and that it is more robust to the noise being colored than the previously published methods.

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

KAUST Repository

Hanna, Amir

2016-11-01

This dissertation presents a unique concept for a device architecture named the nanotube (NT) architecture, which is capable of higher drive current compared to the Gate-All-Around Nanowire architecture when applied to heterostructure Tunnel Field Effect Transistors. Through the use of inner/outer core-shell gates, heterostructure NT TFET leverages physically larger tunneling area thus achieving higher driver current (ION) and saving real estates by eliminating arraying requirement. We discuss the physics of p-type (Silicon/Indium Arsenide) and n-type (Silicon/Germanium hetero-structure) based TFETs. Numerical TCAD simulations have shown that NT TFETs have 5x and 1.6 x higher normalized ION when compared to GAA NW TFET for p and n-type TFETs, respectively. This is due to the availability of larger tunneling junction cross sectional area, and lower Shockley-Reed-Hall recombination, while achieving sub 60 mV/dec performance for more than 5 orders of magnitude of drain current, thus enabling scaling down of Vdd to 0.5 V. This dissertation also introduces a novel thin-film-transistors architecture that is named the Wavy Channel (WC) architecture, which allows for extending device width by integrating vertical fin-like substrate corrugations giving rise to up to 50% larger device width, without occupying extra chip area. The novel architecture shows 2x higher output drive current per unit chip area when compared to conventional planar architecture. The current increase is attributed to both the extra device width and 50% enhancement in field effect mobility due to electrostatic gating effects. Digital circuits are fabricated to demonstrate the potential of integrating WC TFT based circuits. WC inverters have shown 2× the peak-to-peak output voltage for the same input, and ~2× the operation frequency of the planar inverters for the same peak-to-peak output voltage. WC NAND circuits have shown 2× higher peak-to-peak output voltage, and 3× lower high-to-low propagation

Iodine-frequency-stabilized laser diode and displacement-measuring interferometer based on sinusoidal phase modulation

Science.gov (United States)

Duong, Quang Anh; Vu, Thanh Tung; Higuchi, Masato; Wei, Dong; Aketagawa, Masato

2018-06-01

We propose a sinusoidal phase modulation method to achieve both the frequency stabilization of an external-cavity laser diode (ECLD) to an 127I2 saturated absorption transition near 633 nm and displacement measurement using a Mach–Zehnder interferometer. First, the frequency of the ECLD is stabilized to the b 21 hyperfine component of the P(33) 6-3 transition of 127I2 by combining sinusoidal phase modulation by an electro-optic modulator and frequency modulation spectroscopy by chopping the pump beam using an acousto-optic modulator. Even though a small modulation index of m  =  3.768 rad is utilized, a relative frequency stability of 10‑11 order is obtained over a sampling time of 400 s. Secondly, the frequency-stabilized ECLD is applied as a light source to a Mach–Zehnder interferometer. From the two consecutive modulation harmonics (second and third orders) involved in the interferometer signal, the displacement of the moving mirror is determined for four optical path differences (L 0  =  100, 200, 500, and 1000 mm). The measured modulation indexes for the four optical path differences coincide with the designated value (3.768 rad) within 0.5%. Compared with the sinusoidal frequency modulation Michelson interferometer (Vu et al 2016 Meas. Sci. Technol. 27 105201) which was demonstrated by some of the same authors of this paper, the phase modulation Mach–Zhender interferometer could fix the modulation index to a constant value for the four optical path differences. In this report, we discuss the measurement principle, experimental system, and results.

Construction of a liver sinusoid based on the laminar flow on chip and self-assembly of endothelial cells.

Science.gov (United States)

Mi, Shengli; Yi, Xiaoman; Du, Zhichang; Xu, Yuanyuan; Sun, Wei

2018-02-20

The liver is one of the main metabolic organs, and nearly all ingested drugs will be metabolized by the liver. Only a small fraction of drugs are able to come onto the market during drug development, and hepatic toxicity is a major cause for drug failure. Since drug development is costly in both time and materials, an in vitro liver model that can accelerate bioreactions in the liver and reduce drug consumption is imperative in the pharmaceutical industry. The liver on a chip is an ideal alternative for its controllable environment and tiny size, which means constructing a more biomimetic model, reducing material consumption as well as promoting drug diffusion and reaction. In this study, taking advantage of the laminar flow on chips and using natural degradable gel rat tail Collagen-I, we constructed a liver sinusoid on a chip. By synchronously injecting two kinds of cell-laden collagen, HepG2-laden collagen and HUVEC-laden collagen, we formed two collagen layers with a clear borderline. By controlling the HUVEC density and injection of growth factors, HUVECs in collagen formed a monolayer through self-assembly. Thus, a liver sinusoid on a chip was achieved in a more biomimetic environment with a more controllable and uniform distribution of discrete HUVECs. Viability, album secretion and urea synthesis of the live sinusoid on a chip were analysed on days 3, 5 and 7 after collagen injection with acetaminophen treatment at 0 (control), 10 and 20 mM. The results indicated that our liver sinusoid on a chip was able to maintain bioactivity and function for at least 7 d and was beneficial for hepatotoxic drug screening.

Hepatic sinusoid is not well-stirred: estimation of the degree of axial mixing by analysis of lobular concentration gradients formed during uptake of thyroxine by the perfused rat liver

International Nuclear Information System (INIS)

Weisiger, R.A.; Mendel, C.M.; Cavalieri, R.R.

1986-01-01

Two general models have been proposed for predicting the effects of metabolism, protein binding, and plasma flow on the removal of drugs by the liver. These models differ in the degree of plasma mixing assumed to exist within each hepatic sinusoid. The venous equilibrium model treats the sinusoid as a single well-stirred compartment, whereas the sinusoidal model effectively breaks up the sinusoid into a large number of sequentially perfused compartments which do not exchange their contents except through plasma flow. As a consequence, the sinusoidal model, but not the venous equilibrium model, predicts that the concentration of highly extracted drugs will decline as the plasma flows through the hepatic lobule. To determine which of these alternative models best describes the hepatic uptake process, we looked for evidence that concentration gradients are formed during the uptake of [ 125 I]thyroxine by the perfused rat liver. Autoradiography of tissue slices after perfusion of the portal vein at physiologic flow rates with protein-free buffer containing [ 125 I]thyroxine demonstrated a rapid exponential fall in grain density with distance from the portal venule, declining by half for each 8% of the mean length of the sinusoid. Reversing the direction of perfusate flow reversed the direction of the autoradiographic gradients, indicating that they primarily reflect differences in the concentration of thyroxine within the hepatic sinusoids rather than differences in the uptake capacity of portal and central hepatocytes. Analysis of the data using models in which each sinusoid was represented by different numbers of sequentially perfused compartments (1-20) indicated that at least eight compartments were necessary to account for the magnitude of the gradients seen

Using spatiotemporal source separation to identify prominent features in multichannel data without sinusoidal filters.

Science.gov (United States)

Cohen, Michael X

2017-09-27

The number of simultaneously recorded electrodes in neuroscience is steadily increasing, providing new opportunities for understanding brain function, but also new challenges for appropriately dealing with the increase in dimensionality. Multivariate source separation analysis methods have been particularly effective at improving signal-to-noise ratio while reducing the dimensionality of the data and are widely used for cleaning, classifying and source-localizing multichannel neural time series data. Most source separation methods produce a spatial component (that is, a weighted combination of channels to produce one time series); here, this is extended to apply source separation to a time series, with the idea of obtaining a weighted combination of successive time points, such that the weights are optimized to satisfy some criteria. This is achieved via a two-stage source separation procedure, in which an optimal spatial filter is first constructed and then its optimal temporal basis function is computed. This second stage is achieved with a time-delay-embedding matrix, in which additional rows of a matrix are created from time-delayed versions of existing rows. The optimal spatial and temporal weights can be obtained by solving a generalized eigendecomposition of covariance matrices. The method is demonstrated in simulated data and in an empirical electroencephalogram study on theta-band activity during response conflict. Spatiotemporal source separation has several advantages, including defining empirical filters without the need to apply sinusoidal narrowband filters. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

СURRENT FILTERING IN A THREE-PHASE THREE-WIRE POWER SYSTEM AT ASYMMETRIC SINUSOIDAL VOLTAGES

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M. Yu. Artemenko

2018-04-01

Full Text Available Purpose. Investigation of the optimal current distribution between source, shunt active filter and reactive compensator of a three-phase three-wire system that provides consumption of a sinusoidal symmetric current under asymmetric source voltages with minimal power losses was provided. Methodology. The tasks were solved by conducting theoretical and experimental studies. The main provisions of the theory of electrical circuits, the apparatus of mathematical analysis, methods for solving linear differential and algebraic equations, elements of matrix and complex calculus and vector algebra are used. During the development, modern methods and software of computer simulation of electrical engineering complexes and dynamic systems were applied: Matlab-Simulink, MATHCAD. Originality. The principle of compensating current distribution between PAF and reactive compensator of a three-phase three-wire power system with asymmetric sinusoidal voltage was proposed at which the input current is equal to the positive-sequence active current and rms value of PAF current is minimal. The feasibility to compensate the inactive sinusoidal Fryze current by reactive elements under arbitrary combination of load and source parameters was proved and expression for direct calculation of the reactive compensator parameters for generation of inactive Fryze current in the source unbalanced mode was obtained. Practical value. The simulative example for transmission line load showed that combined application of PAF and reactive compensator with the specified distribution of compensating currents ensured a reduction of power losses in 3.273 times and rms value of the SAF current is 12.9 % of rms value total compensation current.

Elementary properties of Ca(2+) channels and their influence on multivesicular release and phase-locking at auditory hair cell ribbon synapses.

Science.gov (United States)

Magistretti, Jacopo; Spaiardi, Paolo; Johnson, Stuart L; Masetto, Sergio

2015-01-01

Voltage-gated calcium (Cav1.3) channels in mammalian inner hair cells (IHCs) open in response to sound and the resulting Ca(2+) entry triggers the release of the neurotransmitter glutamate onto afferent terminals. At low to mid sound frequencies cell depolarization follows the sound sinusoid and pulses of transmitter release from the hair cell generate excitatory postsynaptic currents (EPSCs) in the afferent fiber that translate into a phase-locked pattern of action potential activity. The present article summarizes our current understanding on the elementary properties of single IHC Ca(2+) channels, and how these could have functional implications for certain, poorly understood, features of synaptic transmission at auditory hair cell ribbon synapses.

Elementary properties of Ca2+ channels and their influence on multivesicular release and phase-locking at auditory hair cell ribbon synapses

Science.gov (United States)

Magistretti, Jacopo; Spaiardi, Paolo; Johnson, Stuart L.; Masetto, Sergio

2015-01-01

Voltage-gated calcium (Cav1.3) channels in mammalian inner hair cells (IHCs) open in response to sound and the resulting Ca2+ entry triggers the release of the neurotransmitter glutamate onto afferent terminals. At low to mid sound frequencies cell depolarization follows the sound sinusoid and pulses of transmitter release from the hair cell generate excitatory postsynaptic currents (EPSCs) in the afferent fiber that translate into a phase-locked pattern of action potential activity. The present article summarizes our current understanding on the elementary properties of single IHC Ca2+ channels, and how these could have functional implications for certain, poorly understood, features of synaptic transmission at auditory hair cell ribbon synapses. PMID:25904847

Successful treatment of severe sinusoidal obstruction syndrome despite multiple organ failure with defibrotide after allogeneic stem cell transplantation: a case report.

Science.gov (United States)

Behre, Gerhard; Theurich, Sebastian; Christopeit, Maximilian; Weber, Thomas

2009-03-10

We report a case of sinusoidal obstruction syndrome, a typical and life-threatening complication after allogeneic stem-cell transplantation, successfully treated with defibrotide despite massive multiple organ failure. A 64-year-old Caucasian woman underwent allogeneic peripheral blood stem-cell transplantation from her human leukocyte antigen-identical sister against aggressive lymphoplasmocytoid immunocytoma. Seven days later, the patient developed severe sinusoidal obstruction syndrome according to the modified Seattle criteria. We initiated treatment with defibrotide. Despite early treatment, multiple organ failure with kidney failure requiring dialysis and ventilator-dependent lung failure aggravated the clinical course. Furthermore, central nervous dysfunction occurred as well as transfusion refractory thrombocytopenia. As highlighted in our report, defibrotide is the most promising drug in the treatment of the formerly, almost lethal, severe sinusoidal obstruction syndrome to date. This is demonstrated very clearly in our patient. She improved completely, even after renal, cerebral and respiratory failure.

Simply Adjustable Sinusoidal Oscillator Based on Negative Three-Port Current Conveyors

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R. Sotner

2010-09-01

Full Text Available The paper deals with sinusoidal oscillator employing two controlled second-generation negative-current conveyors and two capacitors. The proposed oscillator has a simple circuit configuration. Electronic (voltage adjusting of the oscillation frequency and condition of oscillation are possible. The presented circuit is verified in PSpice utilizing macro models of commercially available negative current conveyors. The circuit is also verified by experimental measurements. Important characteristics and drawbacks of the proposed circuit and influences of real active elements in the designed circuit are discussed in detail.

Biliary obstruction dissipates bioelectric sinusoidal-canalicular barrier without altering taurocholate uptake

International Nuclear Information System (INIS)

Cotting, J.; Zysset, T.; Reichen, J.

1989-01-01

To study immediate events during extrahepatic cholestasis, we investigated the effect of short-term biliary obstruction on the bioelectrical sinusoidal-canalicular barrier in the rat using molecular weight-matched uncharged and negatively charged inert solute pairs. The bioelectrical barrier averaged -22 +/- 5 and -18 +/- 4 mV (NS) using the pair carboxy-/methoxyinulin and ferrocyanide/sucrose, respectively. After a 20-min biliary obstruction both decreased by 61 and 11%, respectively, but only the large molecular weight pair (the inulins) returned to base line after release of the obstruction. Inert solute clearances were increased after short biliary obstruction depending on molecular size and negative charge (ferrocyanide greater than sucrose greater than carboxyinulin greater than inulin), suggesting that both permeability and bioelectrical barriers were affected by obstruction. The hepatic extraction in vivo of a passively transported drug not excreted into bile (D-propranolol) was not affected by obstruction, whereas that of an actively transported drug (glycocholate) decreased from 66 +/- 8 to 41 +/- 20% during biliary obstruction (P less than 0.01). Unidirectional transfer of glycocholate was not affected by short-term biliary obstruction in the situ perfused rat liver; however, 2 min after [14C]glycocholate administration, increased return was observed in hepatic venous effluent in obstructed animals. Our findings demonstrate a loss of the bioelectrical barrier immediately after short-term biliary obstruction. Decreased hepatic extraction in the view of unaltered sinusoidal uptake demonstrates regurgitation of bile into blood during short-term biliary obstruction

One-dimensional plasma photonic crystals with sinusoidal densities

International Nuclear Information System (INIS)

Qi, L.; Shang, L.; Zhang, S.

2014-01-01

Properties of electromagnetic waves with normal and oblique incidence have been studied for one-dimensional plasma layers with sinusoidal densities. Wave transmittance as a function of wave frequency exhibits photonic band gaps characteristic of photonic crystals. For periodic structures, increasing collision frequency is demonstrated to lead to greater absorption, increasing the modulation factor enlarges the gap width, and increasing incidence angle can change the gap locations of the two polarizations. If a defect layer is introduced by inserting a new plasma layer in the center, a defect mode may appear within the gap. Periodic number, collision frequency, and modulation factor can affect magnitude of the defect mode. The incidence angle enables the frequency to be tuned. Defect layer thickness affects both frequency and number of defect modes. These results may provide theoretical guidance in designing tunable narrow-band filters

Successful treatment of severe sinusoidal obstruction syndrome despite multiple organ failure with defibrotide after allogeneic stem cell transplantation: a case report

Directory of Open Access Journals (Sweden)

Behre Gerhard

2009-03-01

Full Text Available Abstract Introduction We report a case of sinusoidal obstruction syndrome, a typical and life-threatening complication after allogeneic stem-cell transplantation, successfully treated with defibrotide despite massive multiple organ failure. Case presentation A 64-year-old Caucasian woman underwent allogeneic peripheral blood stem-cell transplantation from her human leukocyte antigen-identical sister against aggressive lymphoplasmocytoid immunocytoma. Seven days later, the patient developed severe sinusoidal obstruction syndrome according to the modified Seattle criteria. We initiated treatment with defibrotide. Despite early treatment, multiple organ failure with kidney failure requiring dialysis and ventilator-dependent lung failure aggravated the clinical course. Furthermore, central nervous dysfunction occurred as well as transfusion refractory thrombocytopenia. Conclusion As highlighted in our report, defibrotide is the most promising drug in the treatment of the formerly, almost lethal, severe sinusoidal obstruction syndrome to date. This is demonstrated very clearly in our patient. She improved completely, even after renal, cerebral and respiratory failure.

Scintillations associated with bottomside sinusoidal irregularities in the equatorial F region

Science.gov (United States)

Basu, S.; Basu, S.; Valladares, C. E.; Dasgupta, A.; Whitney, H. E.

1986-01-01

Multisatellite scintillation observations and spaced receiver drift measurements are presented for a category of equatorial F region plasma irregularities characterized by nearly sinusoidal waveforms in the ion number density. The observations were made at Huancayo, Peru, and the measurements at Ancon, Peru, associated with irregularities observed by the Atmospheric-Explorer-E satellite on a few nights in December 1979. Utilizing ray paths to various geostationary satellites, it was found that the irregularities grow and decay almost simultaneously in long-lived patches extending at least 1000 km in the east-west direction.

Electromagnetic characterization of current transformer with toroidal core under sinusoidal conditions

Energy Technology Data Exchange (ETDEWEB)

Koprivica, Branko, E-mail: branko.koprivica@ftn.kg.ac.rs; Milovanovic, Alenka, E-mail: alenka.milovanovic@ftn.kg.ac.rs

2016-04-01

The aim of this paper is to present a new procedure for the electromagnetic analysis of a measuring current transformer under sinusoidal conditions in its electrical and magnetic circuit. The influence of the magnetic hysteresis has been taken into account using the measured inverse magnetization curve and phase lag between the time waveforms of the magnetic field and the magnetic induction. Using the proposed analysis, ratio and phase errors of the current transformer have been calculated. The results of the calculation have been compared with experimental results and a good agreement has been found.

Electrical properties of AlGaN/GaN HEMTs in stretchable geometries

Science.gov (United States)

Tompkins, R. P.; Mahaboob, I.; Shahedipour-Sandvik, F.; Lazarus, N.

2017-10-01

Many biological materials are naturally soft and stretchable, far more so than crystalline semiconductors. Creating systems that can be placed directly on a surface such as human skin has required new approaches in electronic device design and materials, a field known as stretchable electronics. One common method for fabricating a highly brittle semiconductor device able to survive tens of percent strain is to incorporate stress relief structures ('waves'). Although the mechanical advantages of this approach are well known, the effects on the electrical behavior of a device such as a transistor compared to a more traditional geometry have not been studied. Here, AlGaN/GaN high electron mobility transistors (HEMTs) grown on rigid sapphire substrates were fabricated in a common wavy geometry, a sinusoid, with dimensions similar to those used in stretchable electronics. The study analyzes control parameters available to the designer including gate location along the sinusoid, angle the source-drain contacts make with the gate, as well as variation of the gate length at the peak of the sinusoid. Common electrical parameters such as saturation current density, threshold voltage, and transconductance were compared between the sinusoidal and conventional straight geometries and results found to fall to within experimental uncertainty, suggesting shifting to a stretchable geometry is possible without appreciably degrading semiconductor device performance.

Voltage-Mode Four-Phase Sinusoidal Generator and Its Useful Extensions

Directory of Open Access Journals (Sweden)

Sudhanshu Maheshwari

2013-01-01

Full Text Available This paper introduces a new voltage-mode second-order sinusoidal generator circuit with four active elements and six passive elements, including grounded capacitors. The frequency and condition of oscillation can be independently controlled. The effect of active element’s nonidealities and parasitic effects is also studied; the proposed topology is good in absorbing several parasitic elements involved with the active elements. The circuit is advantageous for generating high frequency signals which is demonstrated for 25 MHz outputs. Several circuit extensions are also given which makes the new proposal useful for real circuit adoption. The proposed theory is validated through simulation results.

Identification of a single sinusoidal bile salt uptake system in skate liver

International Nuclear Information System (INIS)

Fricker, G.; Hugentobler, G.; Meier, P.J.; Kurz, G.; Boyer, J.L.

1987-01-01

To identify the sinusoidal bile acid uptake system(s) of skate liver, photoaffinity labeling and kinetic transport studies were performed in isolated plasma membranes as well as intact hepatocytes. In both preparations photoaffinity labeling with the photolabile bile salt derivative revealed the presence of a predominant bile salt binding polypeptide with an apparent molecular weight of 54,000. The [ 3 H]-labeling of this polypeptide was inhibited by taurocholate and cholate in a concentration-dependent manner and was virtually abolished by 1 mM of the anion transport inhibitor 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid. Kinetic studies of hepatic uptake with taurocholate, cholate, and the photoreactive bile salt derivative indicated the involvement of a single transport system, and all three substrates mutually competed with the uptake of each other. Finally, irreversible inhibition of the bile salt uptake system of photoaffinity labeling of hepatocytes with high concentrations of photolabile derivative reduced the V max but the K m of taurocholate uptake. These findings strongly indicate that a single polypeptide with an apparent molecular weight of 54,000 is involved in sinusoidal bile salt uptake into skate hepatocytes. These findings contrast with similar studies in rat liver that implicate both a 54,000- and 48,000-K polypeptide in bile salt uptake and are consistent with a single Na + -independent transport mechanism for hepatic bile salt uptake in this primitive vertebrate

The reliability of nonlinear least-squares algorithm for data analysis of neural response activity during sinusoidal rotational stimulation in semicircular canal neurons.

Science.gov (United States)

Ren, Pengyu; Li, Bowen; Dong, Shiyao; Chen, Lin; Zhang, Yuelin

2018-01-01

Although many mathematical methods were used to analyze the neural activity under sinusoidal stimulation within linear response range in vestibular system, the reliabilities of these methods are still not reported, especially in nonlinear response range. Here we chose nonlinear least-squares algorithm (NLSA) with sinusoidal model to analyze the neural response of semicircular canal neurons (SCNs) during sinusoidal rotational stimulation (SRS) over a nonlinear response range. Our aim was to acquire a reliable mathematical method for data analysis under SRS in vestibular system. Our data indicated that the reliability of this method in an entire SCNs population was quite satisfactory. However, the reliability was strongly negatively depended on the neural discharge regularity. In addition, stimulation parameters were the vital impact factors influencing the reliability. The frequency had a significant negative effect but the amplitude had a conspicuous positive effect on the reliability. Thus, NLSA with sinusoidal model resulted a reliable mathematical tool for data analysis of neural response activity under SRS in vestibular system and more suitable for those under the stimulation with low frequency but high amplitude, suggesting that this method can be used in nonlinear response range. This method broke out of the restriction of neural activity analysis under nonlinear response range and provided a solid foundation for future study in nonlinear response range in vestibular system.

New Realizations of Single OTRA-Based Sinusoidal Oscillators

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Hung-Chun Chien

2014-01-01

Full Text Available This study proposes three new sinusoidal oscillators based on an operational transresistance amplifier (OTRA. Each of the proposed oscillator circuits consists of one OTRA combined with a few passive components. The first circuit is an OTRA-based minimum RC oscillator. The second circuit is capable of providing independent control on the condition of oscillation without affecting the oscillation frequency. The third circuit exhibits independent control of oscillation frequency through a capacitor. This study first introduces the OTRA and the related formulations of the proposed oscillator circuits, and then discusses the nonideal effects, sensitivity analyses, and frequency stability of the presented circuits. The proposed oscillators exhibit low sensitivities and good frequency stability. Because the presented circuits feature low impedance output, they can be connected directly to the next stage without cascading additional voltage buffers. HSPICE simulations and experimental results confirm the feasibility of the new oscillator circuits.

Liver sinusoidal endothelial cells induce immunosuppressive IL-10-producing Th1 cells via the Notch pathway

NARCIS (Netherlands)

Neumann, Katrin; Rudolph, Christine; Neumann, Christian; Janke, Marko; Amsen, Derk; Scheffold, Alexander

2015-01-01

Under homeostasis, liver sinusoidal endothelial cells (LSECs) shift intrahepatic T-cell responses towards tolerance. However, the role of LSECs in the regulation of T-cell-induced liver inflammation is less clear. Here, we studied the capacity of LSECs to modulate pro-inflammatory Th1-cell

The Relationship between fenestrations, sieve plates and rafts in liver sinusoidal endothelial cells.

Directory of Open Access Journals (Sweden)

Dmitri Svistounov

Full Text Available Fenestrations are transcellular pores in endothelial cells that facilitate transfer of substrates between blood and the extravascular compartment. In order to understand the regulation and formation of fenestrations, the relationship between membrane rafts and fenestrations was investigated in liver sinusoidal endothelial cells where fenestrations are grouped into sieve plates. Three dimensional structured illumination microscopy, scanning electron microscopy, internal reflectance fluorescence microscopy and two-photon fluorescence microscopy were used to study liver sinusoidal endothelial cells isolated from mice. There was an inverse distribution between sieve plates and membrane rafts visualized by structured illumination microscopy and the fluorescent raft stain, Bodipy FL C5 ganglioside GM1. 7-ketocholesterol and/or cytochalasin D increased both fenestrations and lipid-disordered membrane, while Triton X-100 decreased both fenestrations and lipid-disordered membrane. The effects of cytochalasin D on fenestrations were abrogated by co-administration of Triton X-100, suggesting that actin disruption increases fenestrations by its effects on membrane rafts. Vascular endothelial growth factor (VEGF depleted lipid-ordered membrane and increased fenestrations. The results are consistent with a sieve-raft interaction, where fenestrations form in non-raft lipid-disordered regions of endothelial cells once the membrane-stabilizing effects of actin cytoskeleton and membrane rafts are diminished.

Aerosol absorption measurement with a sinusoidal phase modulating fiber optic photo thermal interferometer

Science.gov (United States)

Li, Shuwang; Shao, Shiyong; Mei, Haiping; Rao, Ruizhong

2016-10-01

Aerosol light absorption plays an important role in the earth's atmosphere direct and semi-direct radiate forcing, simultaneously, it also has a huge influence on the visibility impairment and laser engineering application. Although various methods have been developed for measuring aerosol light absorption, huge challenge still remains in precision, accuracy and temporal resolution. The main reason is that, as a part of aerosol light extinction, aerosol light absorption always generates synchronously with aerosol light scattering, and unfortunately aerosol light scattering is much stronger in most cases. Here, a novel photo-thermal interferometry is proposed only for aerosol absorption measurement without disturbance from aerosol scattering. The photo-thermal interferometry consists of a sinusoidal phase-modulating single mode fiber-optic interferometer. The thermal dissipation, caused by aerosol energy from photo-thermal conversion when irritated by pump laser through interferometer, is detected. This approach is completely insensitive to aerosol scattering, and the single mode fiber-optic interferometer is compact, low-cost and insensitive to the polarization shading. The theory of this technique is illustrated, followed by the basic structure of the sinusoidal phase-modulating fiber-optic interferometer and demodulation algorithms. Qualitative and quantitative analysis results show that the new photo-thermal interference is a potential approach for aerosol absorption detection and environmental pollution detection.

Generation of hyperchaos from the Chen-Lee system via sinusoidal perturbation

International Nuclear Information System (INIS)

Tam, L.M.; Chen, J.H.; Chen, H.K.; Wai Meng Si Tou

2008-01-01

A system with more than one positive Lyapunov exponent can be classified as a hyperchaotic system. In this study, a sinusoidal perturbation was designed for generating hyperchaos from the Chen-Lee chaotic system. The hyperchaos was identified by the existence of two positive Lyapunov exponents and bifurcation diagrams. The system is hyperchaotic in several different regions of the parameters c, ε, and ω. It was found that this method not only can enhance or suppress chaotic behavior, but also induces chaos in non-chaotic parameter ranges. In addition, two interesting dynamical behaviors, Hopf bifurcation and intermittency, were also found in this study

Generation of hyperchaos from the Chen-Lee system via sinusoidal perturbation

Energy Technology Data Exchange (ETDEWEB)

Tam, L.M. [Department of Electromechanical Engineering, Faculty of Science and Technology, University of Macau, Av. Padre Thomas Pereira S.J., Taipa, Macau (China)], E-mail: fstlmt@umac.mo; Chen, J.H. [Department of Mechanical Engineering, Chung Hua University, Hsinchu, Taiwan (China); Chen, H.K. [Department of Mechanical Engineering, Hsiuping Institute of Technology, Taichung, Taiwan (China); Wai Meng Si Tou [Department of Electromechanical Engineering, Faculty of Science and Technology, University of Macau, Av. Padre Thomas Pereira S.J., Taipa, Macau (China)

2008-11-15

A system with more than one positive Lyapunov exponent can be classified as a hyperchaotic system. In this study, a sinusoidal perturbation was designed for generating hyperchaos from the Chen-Lee chaotic system. The hyperchaos was identified by the existence of two positive Lyapunov exponents and bifurcation diagrams. The system is hyperchaotic in several different regions of the parameters c, {epsilon}, and {omega}. It was found that this method not only can enhance or suppress chaotic behavior, but also induces chaos in non-chaotic parameter ranges. In addition, two interesting dynamical behaviors, Hopf bifurcation and intermittency, were also found in this study.

Unique cell type-specific junctional complexes in vascular endothelium of human and rat liver sinusoids.

Directory of Open Access Journals (Sweden)

Cyrill Géraud

Full Text Available Liver sinusoidal endothelium is strategically positioned to control access of fluids, macromolecules and cells to the liver parenchyma and to serve clearance functions upstream of the hepatocytes. While clearance of macromolecular debris from the peripheral blood is performed by liver sinusoidal endothelial cells (LSECs using a delicate endocytic receptor system featuring stabilin-1 and -2, the mannose receptor and CD32b, vascular permeability and cell trafficking are controlled by transcellular pores, i.e. the fenestrae, and by intercellular junctional complexes. In contrast to blood vascular and lymphatic endothelial cells in other organs, the junctional complexes of LSECs have not yet been consistently characterized in molecular terms. In a comprehensive analysis, we here show that LSECs express the typical proteins found in endothelial adherens junctions (AJ, i.e. VE-cadherin as well as α-, β-, p120-catenin and plakoglobin. Tight junction (TJ transmembrane proteins typical of endothelial cells, i.e. claudin-5 and occludin, were not expressed by rat LSECs while heterogenous immunreactivity for claudin-5 was detected in human LSECs. In contrast, junctional molecules preferentially associating with TJ such as JAM-A, B and C and zonula occludens proteins ZO-1 and ZO-2 were readily detected in LSECs. Remarkably, among the JAMs JAM-C was considerably over-expressed in LSECs as compared to lung microvascular endothelial cells. In conclusion, we show here that LSECs form a special kind of mixed-type intercellular junctions characterized by co-occurrence of endothelial AJ proteins, and of ZO-1 and -2, and JAMs. The distinct molecular architecture of the intercellular junctional complexes of LSECs corroborates previous ultrastructural findings and provides the molecular basis for further analyses of the endothelial barrier function of liver sinusoids under pathologic conditions ranging from hepatic inflammation to formation of liver metastasis.

Current and Voltage Mode Multiphase Sinusoidal Oscillators Using CBTAs

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M. Sagbas

2013-04-01

Full Text Available Current-mode (CM and voltage-mode (VM multiphase sinusoidal oscillator (MSO structures using current backward transconductance amplifier (CBTA are proposed. The proposed oscillators can generate n current or voltage signals (n being even or odd equally spaced in phase. n+1 CBTAs, n grounded capacitors and a grounded resistor are used for nth-state oscillator. The oscillation frequency can be independently controlled through transconductance (gm of the CBTAs which are adjustable via their bias currents. The effects caused by the non-ideality of the CBTA on the oscillation frequency and condition have been analyzed. The performance of the proposed circuits is demonstrated on third-stage and fifth-stage MSOs by using PSPICE simulations based on the 0.25 µm TSMC level-7 CMOS technology parameters.

A transgenic model for conditional induction and rescue of portal hypertension reveals a role of VEGF-mediated regulation of sinusoidal fenestrations.

Directory of Open Access Journals (Sweden)

Dalit May

Full Text Available Portal hypertension (PH is a common complication and a leading cause of death in patients with chronic liver diseases. PH is underlined by structural and functional derangement of liver sinusoid vessels and its fenestrated endothelium. Because in most clinical settings PH is accompanied by parenchymal injury, it has been difficult to determine the precise role of microvascular perturbations in causing PH. Reasoning that Vascular Endothelial Growth Factor (VEGF is required to maintain functional integrity of the hepatic microcirculation, we developed a transgenic mouse system for a liver-specific-, reversible VEGF inhibition. The system is based on conditional induction and de-induction of a VEGF decoy receptor that sequesters VEGF and preclude signaling. VEGF blockade results in sinusoidal endothelial cells (SECs fenestrations closure and in accumulation and transformation of the normally quiescent hepatic stellate cells, i.e. provoking the two processes underlying sinusoidal capillarization. Importantly, sinusoidal capillarization was sufficient to cause PH and its typical sequela, ascites, splenomegaly and venous collateralization without inflicting parenchymal damage or fibrosis. Remarkably, these dramatic phenotypes were fully reversed within few days from lifting-off VEGF blockade and resultant re-opening of SECs' fenestrations. This study not only uncovered an indispensible role for VEGF in maintaining structure and function of mature SECs, but also highlights the vasculo-centric nature of PH pathogenesis. Unprecedented ability to rescue PH and its secondary manifestations via manipulating a single vascular factor may also be harnessed for examining the potential utility of de-capillarization treatment modalities.

3D hepatic cultures simultaneously maintain primary hepatocyte and liver sinusoidal endothelial cell phenotypes.

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Yeonhee Kim

Full Text Available Developing in vitro engineered hepatic tissues that exhibit stable phenotype is a major challenge in the field of hepatic tissue engineering. However, the rapid dedifferentiation of hepatic parenchymal (hepatocytes and non-parenchymal (liver sinusoidal endothelial, LSEC cell types when removed from their natural environment in vivo remains a major obstacle. The primary goal of this study was to demonstrate that hepatic cells cultured in layered architectures could preserve or potentially enhance liver-specific behavior of both cell types. Primary rat hepatocytes and rat LSECs (rLSECs were cultured in a layered three-dimensional (3D configuration. The cell layers were separated by a chitosan-hyaluronic acid polyelectrolyte multilayer (PEM, which served to mimic the Space of Disse. Hepatocytes and rLSECs exhibited several key phenotypic characteristics over a twelve day culture period. Immunostaining for the sinusoidal endothelial 1 antibody (SE-1 demonstrated that rLSECs cultured in the 3D hepatic model maintained this unique feature over twelve days. In contrast, rLSECs cultured in monolayers lost their phenotype within three days. The unique stratified structure of the 3D culture resulted in enhanced heterotypic cell-cell interactions, which led to improvements in hepatocyte functions. Albumin production increased three to six fold in the rLSEC-PEM-Hepatocyte cultures. Only rLSEC-PEM-Hepatocyte cultures exhibited increasing CYP1A1/2 and CYP3A activity. Well-defined bile canaliculi were observed only in the rLSEC-PEM-Hepatocyte cultures. Together, these data suggest that rLSEC-PEM-Hepatocyte cultures are highly suitable models to monitor the transformation of toxins in the liver and their transport out of this organ. In summary, these results indicate that the layered rLSEC-PEM-hepatocyte model, which recapitulates key features of hepatic sinusoids, is a potentially powerful medium for obtaining comprehensive knowledge on liver metabolism

Sinusoidal excitation on the Chua's circuit simulation of limit cycles and chaos

DEFF Research Database (Denmark)

Lindberg, Erik

1994-01-01

of charging”, and stable limit cycle behaviour based on the balance between the energy lost in the regions with mainly positive losses and the energy gained in the regions with mainly negative losses. Convergence problems observed in connection with simulation of the ideal piecewise-linear model are solved......Experiments with modelling and simulation of sinusoidal excitation on Chua's circuit are presented. It is demonstrated that the behaviour of the circuit is based on the interaction of two different kinds of energy balance: chaotic behaviour based on a balance between two unstable “states...

The electronic states calculated using the sinusoidal potential for Cd1-xZnxS quantum dot superlattices

International Nuclear Information System (INIS)

Sakly, A.; Safta, N.; Mejri, H.; Lamine, A. Ben

2011-01-01

Research highlights: → This paper is dedicated to structures based on Cd 1-x Zn x S. - Abstract: The present work reports on a theoretical investigation of superlattices based on Cd 1-x Zn x S quantum dots embedded in an insulating material. The system to model is assumed to be a series of flattened cylindrical quantum dots with a finite barrier at the boundary and is studied using a sinusoidal potential. The electronic states of both Γ 1 - (ground) and Γ 2 - (first excited) minibands have been computed as a function of inter-quantum dot separation and Zn composition. An analysis of the results shows that the widths of Γ 1 - and Γ 2 - minibands decrease as the superlattice period and Zn content increase separately. Moreover, the sinusoidal shape of the confining potential accounts for the coupling between quantum dots quantitatively less than the Kronig-Penney potential model.

Dai-kenchu-to attenuates rat sinusoidal obstruction syndrome by inhibiting the accumulation of neutrophils in the liver.

Science.gov (United States)

Narita, Masato; Hatano, Etsuro; Tamaki, Nobuyuki; Yamanaka, Kenya; Yanagida, Atsuko; Nagata, Hiromitsu; Asechi, Hiroyuki; Takada, Yasutsugu; Ikai, Iwao; Uemoto, Shinji

2009-06-01

Sinusoidal obstruction syndrome (SOS) is drug-induced liver injury that occurs in patients who receive hematopoietic cell transplantation and oxaliplatin-contained chemotherapy. The aim of study was to investigate the pharmacological treatment of SOS using a traditional Japanese medicine, Dai-kenchu-to (DKT). Male Sprague-Dawley rats were treated with monocrotaline (MCT) to induce SOS. The rats were divided into three groups: control, MCT and MCT+DKT groups. In the MCT+DKT group, DKT was gavaged at 12 h after MCT treatment and given every 12 h until the end of the protocol. The rats of MCT group were treated with water instead of DKT. At 48 h after MCT treatment, blood and liver samples were collected. In the MCT+DKT group, the macroscopic and histological findings revealed liver congestion, sinusoidal alteration and the destruction of sinusoidal lining, which were comparable with those of the MCT group. However, the area of hepatic necrosis and serum AST levels significantly decreased in the MCT+DKT group compared with those of the MCT group. Treatment with DKT resulted in the reduction of neutrophil accumulation, myeloperoxidase activity and the expression of cytokine-induced neutrophil chemoattractant (CINC) and intracellular adhesion molecule-1 (ICAM-1) mRNA in the liver compared with those of the MCT group. Treatment with processed ginger, one of the ingredients in DKT, resulted in similar effects to those shown by DKT. Dai-kenchu-to attenuates MCT-induced liver injury by preventing neutrophil-induced liver injury through blockage of upregulation of CINC and ICAM-1 mRNA level.

Upregulation of miR21 and repression of Grhl3 by leptin mediates sinusoidal endothelial injury in experimental nonalcoholic steatohepatitis.

Directory of Open Access Journals (Sweden)

Sahar Pourhoseini

Full Text Available Sinusoidal endothelial dysfunction (SED has been found to be an early event in nonalcoholic steatohepatitis (NASH progression but the molecular mechanisms underlying its causation remains elusive. We hypothesized that adipokine leptin worsens sinusoidal injury by decreasing functionally active nitric oxide synthase 3 (NOS3 via miR21. Using rodent models of NASH, and transgenic mice lacking leptin and leptin receptor, results showed that hyperleptinemia caused a 4-5 fold upregulation of hepatic miR21 as assessed by qRTPCR. The upregulation of miR21 led to a time-dependent repression of its target protein Grhl3 levels as shown by western blot analyses. NOS3-p/NOS3 ratio which is controlled by Grhl3 was significantly decreased in NASH models. SED markers ICAM-1, VEGFR-2, and E-selectin as assessed by immunofluorescence microscopy were significantly up regulated in the progressive phases of NASH. Lack of leptin or its receptor in vivo, reversed the upregulation of miR21 and restored the levels of Grhl3 and NOS3-p/NOS3 ratio coupled with decreased SED dysfunction markers. Interestingly, leptin supplementation in mice lacking leptin, significantly enhanced miR21 levels, decreased Grhl3 repression and NOS3 phosphorylation. Leptin supplementation in isolated primary endothelial cells, Kupffer cells and stellate cells showed increased mir21 expression in stellate cells while sinusoidal injury was significantly higher in all cell types. Finally miR21 KO mice showed increased NOS3-p/NOS3 ratio and reversed SED markers in the rodent models of NASH. The experimental results described here show a close association of leptin-induced miR21 in aiding sinusoidal injury in NASH.

Direct NO decomposition over conventional and mesoporous Cu-ZSM-5 and Cu-ZSM-11 catalysts

DEFF Research Database (Denmark)

Kustova, Marina; Rasmussen, Søren Birk; Kustov, Arkadii

2006-01-01

Conventional Cu-ZSM-5 has for many years been recognized as a unique catalyst for direct NO decomposition. Zeolite-based catalysts have a crystallographically well-defined microporous structure. In such microporous catalysts, the creation and accessibility of the active sites is often influenced...... that ZSM-11 has only straight microporous channels, while ZSNI-5 has both straight and sinusoidal channels. Apparently, there is a preferential formation of active sites and/or improved accessibility in the straight channels compared to the sinusoidal channels, which make the ZSM-11 material a better...

Self-similar decay to the marginally stable ground state in a model for film flow over inclined wavy bottoms

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Tobias Hacker

2012-04-01

Full Text Available The integral boundary layer system (IBL with spatially periodic coefficients arises as a long wave approximation for the flow of a viscous incompressible fluid down a wavy inclined plane. The Nusselt-like stationary solution of the IBL is linearly at best marginally stable; i.e., it has essential spectrum at least up to the imaginary axis. Nevertheless, in this stable case we show that localized perturbations of the ground state decay in a self-similar way. The proof uses the renormalization group method in Bloch variables and the fact that in the stable case the Burgers equation is the amplitude equation for long waves of small amplitude in the IBL. It is the first time that such a proof is given for a quasilinear PDE with spatially periodic coefficients.

An all digital phase locked loop for synchronization of a sinusoidal signal embedded in white Gaussian noise

Science.gov (United States)

Reddy, C. P.; Gupta, S. C.

1973-01-01

An all digital phase locked loop which tracks the phase of the incoming sinusoidal signal once per carrier cycle is proposed. The different elements and their functions and the phase lock operation are explained in detail. The nonlinear difference equations which govern the operation of the digital loop when the incoming signal is embedded in white Gaussian noise are derived, and a suitable model is specified. The performance of the digital loop is considered for the synchronization of a sinusoidal signal. For this, the noise term is suitably modelled which allows specification of the output probabilities for the two level quantizer in the loop at any given phase error. The loop filter considered increases the probability of proper phase correction. The phase error states in modulo two-pi forms a finite state Markov chain which enables the calculation of steady state probabilities, RMS phase error, transient response and mean time for cycle skipping.

Responses of Medullary Lateral Line Units of the Goldfish, Carassius auratus, to Amplitude-Modulated Sinusoidal Wave Stimuli

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Ramadan Ali

2010-01-01

Full Text Available This paper describes the responses of brainstem lateral line units in goldfish, Carassius auratus, to constant-amplitude and to amplitude-modulated sinusoidal water motions. If stimulated with constant-amplitude sinusoidal water motions, units responded with phasic (50% or with sustained (50% increases in dicharge rate. Based on isodisplacement curves, units preferred low (33 Hz, 12.5%, mid (50 Hz, 10% and 100 Hz, 30% or high (200 Hz, 47.5% frequencies. In most units, responses were weakly phase locked to the carrier frequency. However, at a carrier frequency of 50 Hz or 100 Hz, a substantial proportion of the units exhibited strong phase locking. If stimulated with amplitude-modulated water motions, units responded with a burst of discharge to each modulation cycle, that is, units phase locked to the amplitude modulation frequency. Response properties of brainstem units were in many respects comparable to those of midbrain units, suggesting that they emerge first in the lateral line brainstem.

A Comparison Study of Sinusoidal PWM and Space Vector PWM Techniques for Voltage Source Inverter

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Ömer Türksoy

2017-06-01

Full Text Available In this paper, the methods used to control voltage source inverters which have been intensively investigated in recent years are compared. Although the most efficient result is obtained with the least number of switching elements in the inverter topologies, the method used in the switching is at least as effective as the topology. Besides, the selected switching method to control the inverter will play an effective role in suppressing harmonic components while producing the ideal output voltage. There are many derivatives of pulse width modulation techniques that are commonly used to control voltage source inverters. Some of widespread methods are sinusoidal pulse width modulation and space vector pulse width modulation techniques. These modulation techniques used for generating variable frequency and amplitude output voltage in voltage source inverters, have been simulated by using MATLAB/SIMULINK. And, the total harmonic distortions of the output voltages are compared. As a result of simulation studies, sinusoidal pulse width modulation has been found to have more total harmonic distortion in output voltages of voltage source inverters in the simulation. Space vector pulse width modulation has been shown to produce a more efficient output voltage with less total harmonic distortion.

Realisation and advanced engineering of true optical rugate filters based on nanoporous anodic alumina by sinusoidal pulse anodisation

Science.gov (United States)

Santos, Abel; Yoo, Jeong Ha; Rohatgi, Charu Vashisth; Kumeria, Tushar; Wang, Ye; Losic, Dusan

2016-01-01

This study is the first realisation of true optical rugate filters (RFs) based on nanoporous anodic alumina (NAA) by sinusoidal waves. An innovative and rationally designed sinusoidal pulse anodisation (SPA) approach in galvanostatic mode is used with the aim of engineering the effective medium of NAA in a sinusoidal fashion. A precise control over the different anodisation parameters (i.e. anodisation period, anodisation amplitude, anodisation offset, number of pulses, anodisation temperature and pore widening time) makes it possible to engineer the characteristic reflection peaks and interferometric colours of NAA-RFs, which can be finely tuned across the UV-visible-NIR spectrum. The effect of the aforementioned anodisation parameters on the photonic properties of NAA-RFs (i.e. characteristic reflection peaks and interferometric colours) is systematically assessed in order to establish for the first time a comprehensive rationale towards NAA-RFs with fully controllable photonic properties. The experimental results are correlated with a theoretical model (Looyenga-Landau-Lifshitz - LLL), demonstrating that the effective medium of these photonic nanostructures can be precisely described by the effective medium approximation. NAA-RFs are also demonstrated as chemically selective photonic platforms combined with reflectometric interference spectroscopy (RIfS). The resulting optical sensing system is used to assess the reversible binding affinity between a model drug (i.e. indomethacin) and human serum albumin (HSA) in real-time. Our results demonstrate that this system can be used to determine the overall pharmacokinetic profile of drugs, which is a critical aspect to be considered for the implementation of efficient medical therapies.This study is the first realisation of true optical rugate filters (RFs) based on nanoporous anodic alumina (NAA) by sinusoidal waves. An innovative and rationally designed sinusoidal pulse anodisation (SPA) approach in galvanostatic

A two-level voltage source inverter with differentially sinusoidal pulse width modulation used in the interconnection system of a wind turbine generator

Directory of Open Access Journals (Sweden)

Alexandros C. Charalampidis

2014-10-01

Full Text Available This study analyses an interconnection system based on differentially sinusoidal pulse width modulation, used for the interconnection to the grid of a variable speed wind turbine. The modulation technique used provides specific advantages in comparison with the commonly used sinusoidal pulse width modulation (SPWM technique, such as lower DC bus voltage requirements, smaller switching losses for the same switching frequency as well as less higher harmonic content in the voltage waveforms produced. The respective control system is also described in detail. Thus this study provides a guide enabling the design of any interconnection system based on this modulation technique.

Phonological awareness and sinusoidal amplitude modulation in phonological dislexia.

Science.gov (United States)

Peñaloza-López, Yolanda; Herrera-Rangel, Aline; Pérez-Ruiz, Santiago J; Poblano, Adrián

2016-04-01

Dyslexia is the difficulty of children in learning to read and write as results of neurological deficiencies. The objective was to test the Phonological awareness (PA) and Sinusoidal amplitude modulation (SAM) threshold in children with Phonological dyslexia (PD). We performed a case-control, analytic, cross sectional study. We studied 14 children with PD and 14 control children from 7 to 11 years of age, by means of PA measurement and by SAM test. The mean age of dyslexic children was 8.39 years and in the control group was 8.15. Children with PD exhibited inadequate skills in PA, and SAM. We found significant correlations between PA and SAM at 4 Hertz frequency, and calculated regression equations that predicts between one-fourth and one-third of variance of measurements. Alterations in PA and SAM found can help to explain basis of deficient language processing exhibited by children with PD.

The FXR agonist PX20606 ameliorates portal hypertension by targeting vascular remodelling and sinusoidal dysfunction.

Science.gov (United States)

Schwabl, Philipp; Hambruch, Eva; Seeland, Berit A; Hayden, Hubert; Wagner, Michael; Garnys, Lukas; Strobel, Bastian; Schubert, Tim-Lukas; Riedl, Florian; Mitteregger, Dieter; Burnet, Michael; Starlinger, Patrick; Oberhuber, Georg; Deuschle, Ulrich; Rohr-Udilova, Nataliya; Podesser, Bruno K; Peck-Radosavljevic, Markus; Reiberger, Thomas; Kremoser, Claus; Trauner, Michael

2017-04-01

Steroidal farnesoid X receptor (FXR) agonists demonstrated potent anti-fibrotic activities and lowered portal hypertension in experimental models. The impact of the novel non-steroidal and selective FXR agonist PX20606 on portal hypertension and fibrosis was explored in this study. In experimental models of non-cirrhotic (partial portal vein ligation, PPVL, 7days) and cirrhotic (carbon tetrachloride, CCl 4 , 14weeks) portal hypertension, PX20606 (PX,10mg/kg) or the steroidal FXR agonist obeticholic acid (OCA,10mg/kg) were gavaged. We then measured portal pressure, intrahepatic vascular resistance, liver fibrosis and bacterial translocation. PX decreased portal pressure in non-cirrhotic PPVL (12.6±1.7 vs. 10.4±1.1mmHg; p=0.020) and cirrhotic CCl 4 (15.2±0.5 vs. 11.8±0.4mmHg; p=0.001) rats. In PPVL animals, we observed less bacterial translocation (-36%; p=0.041), a decrease in lipopolysaccharide binding protein (-30%; p=0.024) and splanchnic tumour necrosis factor α levels (-39%; p=0.044) after PX treatment. In CCl 4 rats, PX decreased fibrotic Sirius Red area (-43%; p=0.005), hepatic hydroxyproline (-66%; pportal pressure (-14%; p=0.041) by restoring endothelial function, 14week PX therapy additionally inhibited sinusoidal remodelling and decreased portal pressure to a greater extent (-22%; p=0.001). In human liver sinusoidal endothelial cells, PX increased eNOS and DDAH expression. The non-steroidal FXR agonist PX20606 ameliorates portal hypertension by reducing liver fibrosis, vascular remodelling and sinusoidal dysfunction. The novel drug PX20606 activates the bile acid receptor FXR and shows beneficial effects in experimental liver cirrhosis: In the liver, it reduces scarring and inflammation, and also widens blood vessels. Thus, PX20606 leads to an improved blood flow through the liver and decreases hypertension of the portal vein. Additionally, PX20606 improves the altered intestinal barrier and decreases bacterial migration from the gut. Copyright �

[Effect of 50 Hz 1.8 mT sinusoidal electromagnetic fields on bone mineral density in growing rats].

Science.gov (United States)

Gao, Yu-Hai; Zhou, Yan-Feng; Li, Shao-Feng; Li, Wen-Yuan; Xi, Hui-Rong; Yang, Fang-Fang; Chen, Ke-Ming

2017-12-25

To study effects of 50 Hz 1.8 mT sinusoidal electromagnetic fields (SEMFs) on bone mineral density (BMD) in SD rats. Thirty SD rats weighted(110±10) and aged 1 month were randomly divided into control group and electromagnetic field group, 15 in each group. Normal control group of 50 Hz 0 mT density and sinusoidal electromagnetic field group of 50 Hz 1.8 mT were performed respectively with 1.5 h/d and weighted weight once a week, and observed food-intake. Rats were anesthesia by intraperitoneal injection and dual energy X-ray absorptiometry were used to detect bone density of whole body, and detected bone density of femur and vertebral body. Osteocalcin and tartrate-resistant acid phosphatase 5b were detected by ELSA; weighted liver, kidney and uterus to calculate purtenance index, then detected pathologic results by HE. Compared with control group, there was no significant change in weight every week, food-intake every day; no obvious change of bone density of whole body at 2 and 4 weeks, however bone density of whole body, bone density of excised femur and vertebra were increased at 6 weeks. Expression of OC was increased, and TRACP 5b expression was decreased. No change of HE has been observed in liver, kidney and uterus and organic index. 50 Hz 1.8 mT sinusoidal electromagnetic fields could improve bone formation to decrease relevant factors of bone absorbs, to improve peak bone density of young rats, in further provide a basis for clinical research electromagnetic fields preventing osteoporosis foundation.

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

DEFF Research Database (Denmark)

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

2017-01-01

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

Diagnosis of sinusoidal obstruction syndrome by positron emission tomography/computed tomography: report of two cases treated by defibrotide.

Science.gov (United States)

Gauthé, Mathieu; Bozec, Laurence; Bedossa, Pierre

2014-11-01

Sinusoidal obstruction syndrome (SOS) is a potentially fatal liver injury that mainly occurs after myeloablative chemotherapy. We report two cases of SOS investigated by 18F-fluorodeoxyglucose positron emission tomography/computed tomography and treated with defibrotide. © 2014 by the American Association for the Study of Liver Diseases.

Adsorption structure of dimethyl ether on silicalite-1 zeolite determined using single-crystal X-ray diffraction

International Nuclear Information System (INIS)

Fujiyama, Shinjiro; Seino, Shintaro; Kamiya, Natsumi; Nishi, Koji; Yokomori, Yoshinobu

2014-01-01

The most stable sorption site of dimethyl ether on silicalite-1 is the sinusoidal channel. The configuration of guest molecules (linear or bent) plays an important role in determining where the stable sorption site is situated. The adsorption structures of dimethyl ether (DME) on silicalite-1 zeolite (MFI-type) are determined using single-crystal X-ray diffraction. The structure of low-loaded DME-silicalite-1 indicates that all DME molecules are located in the sinusoidal channel, which is the most stable sorption site based on the van der Waals interaction between DME and the framework. The configuration of guest molecules (linear or bent) plays an important role in determining where the stable sorption site is in the pore system of MFI-type zeolites. Bent molecules favor the sinusoidal channel, while linear molecules favor the straight channel. The contribution of DME–DME interactions is considerable in the high-loaded DME-silicalite-1 structure

Cytotoxicity of pyrrolizidine alkaloid in human hepatic parenchymal and sinusoidal endothelial cells: Firm evidence for the reactive metabolites mediated pyrrolizidine alkaloid-induced hepatotoxicity.

Science.gov (United States)

Yang, Mengbi; Ruan, Jianqing; Fu, Peter P; Lin, Ge

2016-01-05

Pyrrolizidine alkaloids (PAs) widely distribute in plants and can cause hepatic sinusoidal obstruction syndrome (HSOS), which typically presents as a primary sinusoidal endothelial cell damage. It is well-recognized that after ingestion, PAs undergo hepatic cytochromes P450 (CYPs)-mediated metabolic activation to generate dehydropyrrolizidine alkaloids (DHPAs), which are hydrolyzed to dehydroretronecine (DHR). DHPAs and DHR are reactive metabolites having same core pyrrole moiety, and can bind proteins to form pyrrole-protein adducts, which are believed as the primary cause for PA-induced HSOS. However, to date, the direct evidences supporting the toxicity of DHPAs and DHR in the liver, in particular in the sinusoidal endothelial cells, are lacking. Using human hepatic sinusoidal endothelial cells (HSEC) and HepG2 (representing hepatic parenchymal cells), cells that lack CYPs activity, this study determined the direct cytotoxicity of dehydromonocrotaline, a representative DHPA, and DHR, but no cytotoxicity of the intact PA (monocrotaline) in both cell lines, confirming that reactive metabolites mediate PA intoxication. Comparing with HepG2, HSEC had significantly lower basal glutathione (GSH) level, and was significantly more susceptible to the reactive metabolites with severer GSH depletion and pyrrole-protein adducts formation. The toxic potency of two reactive metabolites was also compared. DHPA was more reactive than DHR, leading to severer toxicity. In conclusion, our results unambiguously provided the first direct evidence for the critical role of DHPA and DHR in the reactive metabolites-mediated PA-induced hepatotoxicity, which occurs predominantly in HSEC due to severe GSH depletion and the significant formation of pyrrole-protein adducts in HSEC. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Variations in DNA synthesis and mitotic indices in hepatocytes and sinusoid litoral cells of adult intact male mouse along a circadian time span.

Science.gov (United States)

Surur, J M; Moreno, F R; Badrán, A F; Llanos, J M

1985-01-01

Variations of DNA synthesis (DNAS) and mitotic indices along a circadian time span are described in the hepatocyte and sinusoid litoral cell populations of adult intact male mouse liver. Standardized (light from 0600 to 1800) mice were killed in groups of six to nine animals, every 2-4 hr along a circadian time span. Hepatocytes show significant peaks in the synthesis of DNA and the mitotic activity at 0200 and 1400, respectively. These results correspond to those previously described by us in young immature liver, regenerating liver and hepatomas. The phase differences between these peaks and the differences between their absolute values are discussed. Also considered are the practical consequences of our findings for experimental design. The curve of DNA synthesis of sinusoid litoral cells show a peak at 0200. The mitotic index show a bimodal waveform with peaks at 0800 and 2000. The existence of four different cell populations composing the so called sinusoid litoral cells and also the migration into and out of the liver of some macrophages considered as litoral (Kupffer) cells in our counts, makes interpretation of the curves somewhat complicated and deserves further analysis.

Perception of the dynamic visual vertical during sinusoidal linear motion.

Science.gov (United States)

Pomante, A; Selen, L P J; Medendorp, W P

2017-10-01

The vestibular system provides information for spatial orientation. However, this information is ambiguous: because the otoliths sense the gravitoinertial force, they cannot distinguish gravitational and inertial components. As a consequence, prolonged linear acceleration of the head can be interpreted as tilt, referred to as the somatogravic effect. Previous modeling work suggests that the brain disambiguates the otolith signal according to the rules of Bayesian inference, combining noisy canal cues with the a priori assumption that prolonged linear accelerations are unlikely. Within this modeling framework the noise of the vestibular signals affects the dynamic characteristics of the tilt percept during linear whole-body motion. To test this prediction, we devised a novel paradigm to psychometrically characterize the dynamic visual vertical-as a proxy for the tilt percept-during passive sinusoidal linear motion along the interaural axis (0.33 Hz motion frequency, 1.75 m/s 2 peak acceleration, 80 cm displacement). While subjects ( n =10) kept fixation on a central body-fixed light, a line was briefly flashed (5 ms) at different phases of the motion, the orientation of which had to be judged relative to gravity. Consistent with the model's prediction, subjects showed a phase-dependent modulation of the dynamic visual vertical, with a subject-specific phase shift with respect to the imposed acceleration signal. The magnitude of this modulation was smaller than predicted, suggesting a contribution of nonvestibular signals to the dynamic visual vertical. Despite their dampening effect, our findings may point to a link between the noise components in the vestibular system and the characteristics of dynamic visual vertical. NEW & NOTEWORTHY A fundamental question in neuroscience is how the brain processes vestibular signals to infer the orientation of the body and objects in space. We show that, under sinusoidal linear motion, systematic error patterns appear in the

Comparison of distributed vortex receptivity coefficients at excitation of 3D TS-waves in presence and absence of surface waviness and pressure gradient

Science.gov (United States)

Borodulin, V. I.; Ivanov, A. V.; Kachanov, Y. S.; Mischenko, D. A.; Fedenkova, A. A.

2016-10-01

The paper is devoted to quantitative experimental investigation of effective mechanisms of excitation of 3D TS instability waves due to distributed boundary layer receptivity to free-stream vortices. Experiments carried out in a self-similar boundary layer with Hartree parameter βH = -0.115 and concentrated on studying two receptivity mechanisms connected with distributed scattering of 3D unsteady free-stream vortices both on the natural boundary layer nonuniformity (smooth surface) and on 2D surface nonuniformity (waviness). Obtained quantitative characteristics (distributed receptivity coefficients) are compared directly with those obtained in Blasius boundary layer. It is found that the adverse pressure gradient leads to reduction of efficiency of the vortex-roughness receptivity mechanism.

Erosion and deposition by supercritical density flows during channel avulsion and backfilling: Field examples from coarse-grained deepwater channel-levée complexes (Sandino Forearc Basin, southern Central America)

Science.gov (United States)

Lang, Jörg; Brandes, Christian; Winsemann, Jutta

2017-03-01

Erosion and deposition by supercritical density flows can strongly impact the facies distribution and architecture of submarine fans. Field examples from coarse-grained channel-levée complexes from the Sandino Forearc Basin (southern Central America) show that cyclic-step and antidune deposits represent common sedimentary facies of these depositional systems and relate to the different stages of avulsion, bypass, levée construction and channel backfilling. During channel avulsion, large-scale scour-fill complexes (18 to 29 m deep, 18 to 25 m wide, 60 to > 120 m long) were incised by supercritical density flows. The multi-storey infill of the large-scale scour-fill complexes comprises amalgamated massive, normally coarse-tail graded or widely spaced subhorizontally stratified conglomerates and pebbly sandstones, interpreted as deposits of the hydraulic-jump zone of cyclic steps. The large-scale scour-fill complexes can be distinguished from small-scale channel fills based on the preservation of a steep upper margin and a coarse-grained infill comprising mainly amalgamated hydraulic-jump zone deposits. Channel fills include repeated successions deposited by cyclic steps with superimposed antidunes. The deposits of the hydraulic-jump zone of cyclic steps comprise regularly spaced scours (0.2 to 2.6 m deep, 0.8 to 23 m long) infilled by intraclast-rich conglomerates or pebbly sandstones, displaying normal coarse-tail grading or backsets. These deposits are laterally and vertically associated with subhorizontally stratified, low-angle cross-stratified or sinusoidally stratified sandstones and pebbly sandstones, which were deposited by antidunes on the stoss side of the cyclic steps during flow re-acceleration. The field examples indicate that so-called spaced stratified deposits may commonly represent antidune deposits with varying stratification styles controlled by the aggradation rate, grain-size distribution and amalgamation. The deposits of small-scale cyclic

[The sequential use of local vacuum magnetotherapy and papaverine electrophoresis with sinusoidal modulated currents in impotence].

Science.gov (United States)

Karpukhin, I V; Bogomol'nyĭ, V A

1997-01-01

105 patients with chronic nonspecific prostatitis were examined and treated with papaverin electrophoresis using sinusoidal modulated currents (SMC) and local vacuum magnetotherapy (LVMT). Papaverin SMC electrophoresis and LVMT stimulated cavernous circulation. The highest stimulation was achieved at successive use of LVMT and the electrophoresis. LVMT followed by the electrophoresis maintained good cavernous circulation for 5-6 hours after the procedure in the course of which several spontaneous erections were observed.

Sinusoidal oscillators with lower gain requirements at higher frequencies based on an explicit tanh(x) nonlinearity

KAUST Repository

Elwakil, Ahmed S.

2009-04-28

Two novel sinusoidal oscillator structures with an explicit tanh(x) nonlinearity are proposed. The oscillators have the attractive feature: the higher the operating frequency, the lower the necessary gain required to start oscillations. A nonlinear model for the two oscillators is derived and verified numerically. Spice simulations using AMS BiCMOS 0.35 μ model parameters and experimental results are shown. Copyright © 2009 John Wiley & Sons, Ltd.

Response of resonant gravitational wave detectors to damped sinusoid signals

International Nuclear Information System (INIS)

Pai, A; Celsi, C; Pallottino, G V; D'Antonio, S; Astone, P

2007-01-01

Till date, the search for burst signals with resonant gravitational wave (GW) detectors has been done using the δ-function approximation for the signal, which was reasonable due to the very small bandwidth of these detectors. However, now with increased bandwidth (of the order of 10 or more Hz) and with the possibility of comparing results with interferometric GW detectors (broad-band), it is very important to exploit the resonant detectors' capability to detect also signals with specific wave shapes. As a first step, we present a study of the response of resonant GW detectors to damped sinusoids with given frequency and decay time and report on the development of a filter matched to these signals. This study is a preliminary step towards the comprehension of the detector response and of the filtering for signals such as the excitation of stellar quasi-normal modes

Real-time detection of musical onsets with linear prediction and sinusoidal modeling

Science.gov (United States)

Glover, John; Lazzarini, Victor; Timoney, Joseph

2011-12-01

Real-time musical note onset detection plays a vital role in many audio analysis processes, such as score following, beat detection and various sound synthesis by analysis methods. This article provides a review of some of the most commonly used techniques for real-time onset detection. We suggest ways to improve these techniques by incorporating linear prediction as well as presenting a novel algorithm for real-time onset detection using sinusoidal modelling. We provide comprehensive results for both the detection accuracy and the computational performance of all of the described techniques, evaluated using Modal, our new open source library for musical onset detection, which comes with a free database of samples with hand-labelled note onsets.

Sensitivity of echo enabled harmonic generation to sinusoidal electron beam energy structure

Directory of Open Access Journals (Sweden)

E. Hemsing

2017-06-01

Full Text Available We analytically examine the bunching factor spectrum of a relativistic electron beam with sinusoidal energy structure that then undergoes an echo-enabled harmonic generation (EEHG transformation to produce high harmonics. The performance is found to be described primarily by a simple scaling parameter. The dependence of the bunching amplitude on fluctuations of critical parameters is derived analytically, and compared with simulations. Where applicable, EEHG is also compared with high gain harmonic generation (HGHG and we find that EEHG is generally less sensitive to several types of energy structure. In the presence of intermediate frequency modulations like those produced by the microbunching instability, EEHG has a substantially narrower intrinsic bunching pedestal.

Effects of irregular two-dimensional and three-dimensional surface roughness in turbulent channel flows

International Nuclear Information System (INIS)

De Marchis, M.; Napoli, E.

2012-01-01

Highlights: ► 3D irregular rough surfaces produce higher effects than those observed over 2D. ► Effective slope is a geometrical parameter representative of the roughness effects. ► 3D rough surfaces enhance the turbulence isotropization. ► 2D and 3D irregular roughness partially support the wall similarity. ► Irregular rough surfaces shear some features with regular rough walls. - Abstract: Wall-resolved Large Eddy Simulation of fully developed turbulent channel flows over two different rough surfaces is performed to investigate on the effects of irregular 2D and 3D roughness on the turbulence. The two geometries are obtained through the superimposition of sinusoidal functions having random amplitudes and different wave lengths. In the 2D configuration the irregular shape in the longitudinal direction is replicated in the transverse one, while in the 3D case the sinusoidal functions are generated both in streamwise and spanwise directions. Both channel walls are roughened in such a way as to obtain surfaces with statistically equivalent roughness height, but different shapes. In order to compare the turbulence properties over the two rough walls and to analyse the differences with a smooth wall, the simulations are performed at the same Reynolds number Re τ = 395. The same mean roughness height h = 0.05δ (δ the half channel height) is used for the rough walls. The roughness function obtained with the 3D roughness is larger than in the 2D case, although the two walls share the same mean height. Thus, the considered irregular 3D roughness is more effective in reducing the flow velocity with respect to the 2D roughness, coherently with the literature results that identified a clear dependence of the roughness function on the effective slope (see ), higher in the generated 3D rough wall. The analysis of higher-order statistics shows that the effects of the roughness, independently on its two- or three-dimensional shape, are mainly confined in the inner

Exact solution of unsteady flow generated by sinusoidal pressure gradient in a capillary tube

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M. Abdulhameed

2015-12-01

Full Text Available In this paper, the mathematical modeling of unsteady second grade fluid in a capillary tube with sinusoidal pressure gradient is developed with non-homogenous boundary conditions. Exact analytical solutions for the velocity profiles have been obtained in explicit forms. These solutions are written as the sum of the steady and transient solutions for small and large times. For growing times, the starting solution reduces to the well-known periodic solution that coincides with the corresponding solution of a Newtonian fluid. Graphs representing the solutions are discussed.

SnO2 Nanoparticles Decorated 2D Wavy Hierarchical Carbon Nanowalls with Enhanced Photoelectrochemical Performance

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Noor Hamizah Khanis

2017-01-01

Full Text Available Two-dimensional carbon nanowall (2D-CNW structures were prepared by hot wire assisted plasma enhanced chemical vapor deposition (hw-PECVD system on silicon substrates. Controlled variations in the film structure were observed with increase in applied rf power during deposition which has been established to increase the rate of dissociation of precursor gases. The structural changes resulted in the formation of wavy-like features on the 2D-CNW, thus further enhancing the surface area of the nanostructures. The FESEM results confirmed the morphology transformation and conclusively showed the evolution of the 2D-CNW novel structures while Raman results revealed increase in ID/IG ratio indicating increase in the presence of disordered domains due to the presence of open edges on the 2D-CNW structures. Subsequently, the best 2D-CNW based on the morphology and structural properties was functionalized with tin oxide (SnO2 nanoparticles and used as a working electrode in a photoelectrochemical (PEC measurement system. Intriguingly, the SnO2 functionalized 2D-CNW showed enhancement in both Mott-Schottky profiles and LSV properties which suggested that these hierarchical networks showed promising potential application as effective charge-trapping medium in PEC systems.

Isothermal sinusoidal analysis of balanced compound Vuilleumier heat pumps

International Nuclear Information System (INIS)

Finkelstein, T.

1992-01-01

This paper reports on Vuilleumier heat pumps with balanced compounding which have been under investigation for about fifteen years but have not yet reached the stage of commercial utilization. Previously published analytical treatment based upon isothermal treatment of the variable-volume spaces resulted in closed form solution of considerable complexity of the coupled differential equations but applied only to free piston machines. In contrast, the procedure presented here is based on previously demonstrated sinusoidal excursions of the reciprocators. It is of the same order of accuracy, but much more simple and usable. It was found that there is only negligible difference between the results of the present and the previous approach. Additionally, the treatment presented here is applicable to kinematic machines, as well as to free piston machines. For the latter design, an equation for the natural frequency is also derived. Ideal proportions and practical expressions for the energy streams are derived. Gas forces are plotted versus displacement and it is shown that they are equivalent to a linear spring, which is of importance for the concept of a free-piston design

The 3-D alignment of objects in dynamic PET scans using filtered sinusoidal trajectories of sinogram

International Nuclear Information System (INIS)

Kostopoulos, Aristotelis E.; Happonen, Antti P.; Ruotsalainen, Ulla

2006-01-01

In this study, our goal is to employ a novel 3-D alignment method for dynamic positron emission tomography (PET) scans. Because the acquired data (i.e. sinograms) often contain noise considerably, filtering of the data prior to the alignment presumably improves the final results. In this study, we utilized a novel 3-D stackgram domain approach. In the stackgram domain, the signals along the sinusoidal trajectory signals of the sinogram can be processed separately. In this work, we performed angular stackgram domain filtering by employing well known 1-D filters: the Gaussian low-pass filter and the median filter. In addition, we employed two wavelet de-noising techniques. After filtering we performed alignment of objects in the stackgram domain. The local alignment technique we used is based on similarity comparisons between locus vectors (i.e. the signals along the sinusoidal trajectories of the sinogram) in a 3-D neighborhood of sequences of the stackgrams. Aligned stackgrams can be transformed back to sinograms (Method 1), or alternatively directly to filtered back-projected images (Method 2). In order to evaluate the alignment process, simulated data with different kinds of additive noises were used. The results indicated that the filtering prior to the alignment can be important concerning the accuracy

A Statistical and Spectral Model for Representing Noisy Sounds with Short-Time Sinusoids

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Myriam Desainte-Catherine

2005-07-01

Full Text Available We propose an original model for noise analysis, transformation, and synthesis: the CNSS model. Noisy sounds are represented with short-time sinusoids whose frequencies and phases are random variables. This spectral and statistical model represents information about the spectral density of frequencies. This perceptually relevant property is modeled by three mathematical parameters that define the distribution of the frequencies. This model also represents the spectral envelope. The mathematical parameters are defined and the analysis algorithms to extract these parameters from sounds are introduced. Then algorithms for generating sounds from the parameters of the model are presented. Applications of this model include tools for composers, psychoacoustic experiments, and pedagogy.

Mixed convective flow of immiscible viscous fluids confined between ...

African Journals Online (AJOL)

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International Journal of Engineering, Science and Technology ... finite difference methods to analyze the problem of natural convection boundary layer flow along a complex vertical surface ... analyzed the flow of two immiscible fluids in a parallel plate channel ... wavy and flat walls are maintained at constant temperatures w.

Electromagnetohydrodynamic flow through a microparallel channel with corrugated walls

International Nuclear Information System (INIS)

Buren, Mandula; Jian, Yongjun; Chang, Long

2014-01-01

In this paper a perturbation method is introduced to study the electromagnetohydrodynamic (EMHD) flow in a microparallel channel with slightly corrugated walls. The corrugations of the two walls are periodic sinusoidal waves of small amplitude either in phase or half-period out of phase, and the perturbation solutions of velocity and volume flow rate are obtained. Using numerical computation the effects of the corrugations on the flow are graphically analysed. The results show that the influence of corrugation on the flow decreases with Hartmann number. The phase difference of wall corrugations becomes unimportant when the wavenumber is greater than 3 or when the Hartmann number is greater than 4. With the increase in wavenumber, the decreasing effects of corrugations on the flow increase. When the wavenumber is smaller than the threshold wavenumber (it is a function of Hartmann number) and the wall corrugations are half-period out of phase, the corrugations can enhance the mean velocity of EMHD flow. However, the mean velocity is always decreased when the corrugations are in phase. (paper)

Bottomside sinusoidal irregularities in the equatorial F region. II - Cross-correlation and spectral analysis

Science.gov (United States)

Cragin, B. L.; Hanson, W. B.; Mcclure, J. P.; Valladares, C. E.

1985-01-01

Equatorial bottomside sinusoidal (BSS) irregularities have been studied by applying techniques of cross-correlation and spectral analysis to the Atmosphere Explorer data set. The phase of the cross-correlations of the plasma number density is discussed and the two drift velocity components observed using the retarding potential analyzer and ion drift meter on the satellite are discussed. Morphology is addressed, presenting the geographical distributions of the occurrence of BSS events for the equinoxes and solstices. Physical processes including the ion Larmor flux, interhemispheric plasma flows, and variations in the lower F region Pedersen conductivity are invoked to explain the findings.

Sinusoidal Obstruction Syndrome During Chemotherapy of Pediatric Cancers and its Successful Management With Defibrotide.

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Kizilocak, Hande; Dikme, Gürcan; Özdemir, Nihal; Kuruğoğlu, Sebuh; Adaletli, İbrahim; Erkan, Tülay; Celkan, Tiraje

2017-10-01

Sinusoidal obstruction syndrome (SOS) is a life-threatening complication generally occurring after hematopoietic stem cell transplantation. SOS after standard dose chemotherapy in malignancies is rare. Between the year 1995 and 2016, 414 patients were diagnosed with acute lymphoblastic leukemia and 113 patients were diagnosed with Wilms tumor in our institution. Among these patients, 4 patients with acute lymphoblastic leukemia (0.96%) and 2 patients with Wilms tumor (1.7%) developed SOS during treatment. SOS behaves like a local disseminated intravascular coagulation. Defibrotide has proved to be effective in SOS. In this article, we report our experience with defibrotide in SOS.

Additional Energy Losses from Asymmetric and Non-Sinusoidal Current in an Electrical Facility and Methods of their Reduction

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Tarasov Evgeniy V.

2015-01-01

Full Text Available Influence of the asymmetry and higher harmonics of current on the operation of an electrical facility is analyzed. The level of additional losses from the asymmetric and non-sinusoidal currents is evaluated for a 110 kV electrical network in the Siberian Region of the Russian Federation. Methods for reducing the additional energy losses in the electrical facility are suggested.

Additional Energy Losses from Asymmetric and Non-Sinusoidal Current in an Electrical Facility and Methods of their Reduction

OpenAIRE

Tarasov, Evgeny Vladimirovich; Bulyga, Leonid Leonidovich; Ushakov, Vasily Yakovlevich; Kharlov, Nikolay Nikolaevich

2015-01-01

Influence of the asymmetry and higher harmonics of current on the operation of an electrical facility is analyzed. The level of additional losses from the asymmetric and non-sinusoidal currents is evaluated for a 110 kV electrical network in the Siberian Region of the Russian Federation. Methods for reducing the additional energy losses in the electrical facility are suggested.

Contrast-enhanced ultrasonography of hepatocellular carcinoma: Correlation between quantitative parameters and arteries in neoangiogenesis or sinusoidal capillarization

International Nuclear Information System (INIS)

Pei Xiaoqing; Liu Longzhong; Zheng Wei; Cai Muyan; Han Feng; He Jiehua; Li Anhua; Chen Minshan

2012-01-01

Objective: The quantitative parameters in contrast-enhanced ultrasonography-time–intensity curve of hepatocellular carcinoma (HCC) were studied to explore their potential importance in monitoring the effects of anti-angiogenic therapy for HCC. Methods: 115 HCC patients were studied with contrast-enhanced ultrasonography-time–intensity curve (CEUS-TIC) and with immunohistochemical analysis of tissue sections. The CEUS images were analyzed off-line to obtained quantitative parameters including maximum of intensity (IMAX), rise time (RT), time to peak (TTP), mean transit time (mTT), rise slope (RS), and washout time (WT). Monoclonal antibodies specific for smooth muscle actin and anti-CD34 were used to observe unpaired arteries (UAs) and microvessel area (MVA) of sinusoidal capillarization, respectively. The UAs and MVA of 82 HCC cases were successfully stained. Results: The number of UAs had moderate correlation with RT (r = −0.446), TTP (r = −0.432), and RS (r = 0.431) (P < 0.05), and it had mild correlation with IMAX (r = 0.303) and WT (r = 0.285) (P < 0.05). MVA of sinusoidal capillarization had no correlation with perfusion parameters. Conclusion: Quantitative CEUS-TIC parameters reflecting hemodynamics of tumors are correlated with UAs, but not with MVA, and they might be used to monitor the effects of anti-angiogenic therapy on HCC.

Defibrotide: An Oligonucleotide for Sinusoidal Obstruction Syndrome.

Science.gov (United States)

Aziz, May T; Kakadiya, Payal P; Kush, Samantha M; Weigel, Kylie; Lowe, Denise K

2018-02-01

To review the efficacy and safety of defibrotide as well as its pharmacology, mechanism of action, pharmacokinetics (PK), drug-drug interactions, dosing, cost considerations, and place in therapy. A PubMed search was performed through August 2017 using the terms defibrotide, oligonucleotide, hepatic veno-occlusive disease (VOD), sinusoidal obstruction syndrome (SOS), and hematopoietic cell transplantation (HCT). Other data sources were from references of identified studies, review articles, and conference abstracts plus manufacturer product labeling and website, the Food and Drug Administration website, and clinicaltrials.gov. English-language trials that examined defibrotide's pharmacodynamics, mechanism, PK, efficacy, safety, dosing, and cost-effectiveness were included. Trials have confirmed the safety and efficacy of defibrotide for treatment of VOD/SOS in adult and pediatric HCT patients, with complete response rates and day +100 overall survival rates ranging from 25.5% to 76% and 35% to 64%, respectively. The British Committee for Standards in Haematology/British Society for Blood and Marrow Transplantation Guidelines recommend defibrotide prophylaxis in pediatric and adult HCT patients with risk factors for VOD/SOS; however, its prophylactic use in the United States is controversial. Although there are efficacy data to support this strategy, cost-effectiveness data have not shown it to be cost-effective. Defibrotide has manageable toxicities, with low rates of grade 3 to 4 adverse effects. Defibrotide is the first medication approved in the United States for the treatment of adults and children with hepatic VOD/SOS, with renal or pulmonary dysfunction following HCT. Data evaluating defibrotide for VOD/SOS prevention are conflicting and have not shown cost-effectiveness.

A study of unsteady physiological magneto-fluid flow and heat transfer through a finite length channel by peristaltic pumping.

Science.gov (United States)

Tripathi, Dharmendra; Bég, O Anwar

2012-08-01

Magnetohydrodynamic peristaltic flows arise in controlled magnetic drug targeting, hybrid haemodynamic pumps and biomagnetic phenomena interacting with the human digestive system. Motivated by the objective of improving an understanding of the complex fluid dynamics in such flows, we consider in the present article the transient magneto-fluid flow and heat transfer through a finite length channel by peristaltic pumping. Reynolds number is small enough and the wavelength to diameter ratio is large enough to negate inertial effects. Analytical solutions for temperature field, axial velocity, transverse velocity, pressure gradient, local wall shear stress, volume flowrate and averaged volume flowrate are obtained. The effects of the transverse magnetic field, Grashof number and thermal conductivity on the flow patterns induced by peristaltic waves (sinusoidal propagation along the length of channel) are studied using graphical plots. The present study identifies that greater pressure is required to propel the magneto-fluid by peristaltic pumping in comparison to a non-conducting Newtonian fluid, whereas, a lower pressure is required if heat transfer is effective. The analytical solutions further provide an important benchmark for future numerical simulations.

Drag reduction by streamwise traveling wave-like Lorenz Force in channel flow

International Nuclear Information System (INIS)

Mamori, Hiroya; Fukagata, Koji

2011-01-01

Skin-friction drag reduction effect of traveling wave-like wall-normal Lorenz force in a fully developed turbulent channel flow is investigated by means of direct numerical simulation. A sinusoidal profile of the wall-normal body force is assumed as the Lorenz force. While upstream traveling waves reduce the drag in the case of blowing/suction, standing waves reduce it in the case of present forcing. Visualization of vortical structure under the standing wave-like wall-normal Lorenz force reveals that the near-wall streamwise vortices, which increase the skin-friction drag, disappear and spanwise roller-like vortices are generated instead. Three component decomposition of the Reynolds shear stress indicates that the spanwise roller-like vortices contribute to the negative Reynolds shear stress in the region near the wall, similarly to the case of laminar flows. While the analogy between the wall-normal and streamwise forcings can be expected, the statistics are found to exhibit different behaviors due to the difference in the energy flow.

Turbulent Boundary Layer Over Geophysical-like Topographies

Science.gov (United States)

Chamorro, L. P.; Hamed, A. M.; Castillo, L.

2016-12-01

An experimental investigation of the flow and the turbulence structure over 2D and 3D large-scale wavy walls was performed using high-resolution planar particle image velocimetry in a refractive-index-matching (RIM) channel. Extensive measurements were performed to characterize the developing and developed flows. The 2D wall is described by a sinusoidal wave in the streamwise direction with amplitude to wavelength ratio a/λx = 0.05, while the 3D wall has an additional wave superimposed in the spanwise direction with a/λy = 0.1. The flow over these walls was characterized at Reynolds numbers of 4000 and 40000, based on the bulk velocity and the channel half height. The walls have an amplitude to boundary layer thickness ratio a/δ99 ≈ 0.1 and resemble large-scale and geophysical-like roughnesses found in rivers beds and natural terrain. Instantaneous velocity fields and time-averaged turbulence quantities reveal strong coupling between large-scale topography and the turbulence dynamics near the wall. Turbulence statistics for both walls show the presence of a well-structured shear layer past the roughness crests. Analysis of the turbulent kinetic energy production rate suggests that the shear layer is responsible for the majority of turbulence production across both walls. However, the 3D wall exhibits preferential spanwise flows that are thought to result in the multiple distinctive flow features for the 3D wall including comparatively reduced spanwise vorticity and decreased turbulence levels. Further insight on the effect of roughness three-dimensionality and Reynolds number is drawn in both the developed and developing regions through proper orthogonal decomposition (POD) and quadrant analysis.

Flow and heat transfer over a rotating disk with surface roughness

International Nuclear Information System (INIS)

Yoon, Myung Sup; Hyun, Jae Min; Park, Jun Sang

2007-01-01

A numerical study is made of flow and heat transfer near an infinite disk, which rotates steadily about the longitudinal axis. The surface of the disk is characterized by axisymmetric, sinusoidally-shaped roughness. The representative Reynolds number is large. Numerical solutions are acquired to the governing boundary-layer-type equations. The present numerical results reproduce the previous data for a flat disk. For a wavy surface disk, the radial distributions of local skin friction coefficient and local Nusselt number show double periodicity, which is in accord with the previous results. Physical explanations are provided for this finding. The surface-integrated torque coefficient and average Nusselt number increase as the surface roughness parameter increases. The effect of the Rossby number is also demonstrated

Large right ventricular sinusoids in an infant with aorta-left ventricular tunnel and proximal right coronary artery atresia.

Science.gov (United States)

Chen, Peter C; Spinner, Joseph A; Heinle, Jeffrey S

2018-07-01

We report a 1-month-old infant diagnosed with an aorta-left ventricular tunnel, ventricular septal defect, and right coronary atresia with right ventricular sinusoids. The patient's anatomy and physiology did not indicate right-ventricular-dependent coronary circulation, and therefore right ventricular decompression could be performed without compromising coronary perfusion during surgical correction. A detailed understanding of the coronary anatomy is critical in managing this defect when coronary anomalies are present.

Instrumentation to Measure the Capacitance of Biosensors by Sinusoidal Wave Method

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Pavan Kumar KATHUROJU

2009-09-01

Full Text Available Micro Controller based instrumentation to measure the capacitance of biosensors is developed. It is based on frequency domain technique with sinusoidal wave input. Changes in the capacitance of biosensor because of the analyte specific reaction are calculated by knowing the current flowing through the sample. A dedicated 8-bit microcontroller (AT89C52 and its associated peripherals are employed for the hardware and application specific software is developed in ‘C’ language. The paper describes the methodology, instrumentation details along with a specific application to glucose sensing. The measurements are conducted with glucose oxidase based capacitance biosensor and the obtained results are compared with the conventional method of sugar measurements using the UV-Visible spectroscopy (Phenol-Sulphuric acid assay method. Measurement accuracy of the instrument is found to be ± 5 %. Experiments are conducted on glucose sensor with different bias voltages. It is found that for bias voltages varying from 0.5 to 0.7 Volt, the measurements are good for this application.

Mixed convection flow and heat transfer in a vertical wavy channel ...

African Journals Online (AJOL)

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The flow in the porous medium is modeled using Darcy-Brinkman equation. ... Composite layers are also find application in porous journal bearings. ...... to (57) we obtain to the order of λ , the following set of ordinary differential equations. ...... The authors would like to thank UGC-New Delhi for the financial support under ...

Channel Power in Multi-Channel Environments

NARCIS (Netherlands)

M.G. Dekimpe (Marnik); B. Skiera (Bernd)

2004-01-01

textabstractIn the literature, little attention has been paid to instances where companies add an Internet channel to their direct channel portfolio. However, actively managing multiple sales channels requires knowing the customers’ channel preferences and the resulting channel power. Two key

A pre-heating method based on sinusoidal alternating current for lithium-ion battery

Science.gov (United States)

Fan, Wentao; Sun, Fengchun; Guo, Shanshan

2018-04-01

In this paper, a method of low temperature pre-heating of sinusoidal alternating current (SAC) is proposed. Generally, the lower the frequency of the AC current, the higher the heat generation rate. Yet at low frequency, there is a risk of lithium-ion deposition during the half cycle of charging. This study develops a temperature-adaptive, deposition-free AC pre-heating method. a equivalent electric circuit(EEC) model is established to predict the heat generation rate and temperature status, whose parameters are calibrated from the EIS impedance measurements. The effects of current frequency and amplitude on the heating effect are investigated respectively. A multistep temperature-adaptive amplitude strategy is proposed and the cell can be heated from -20°C to 5°C within 509s at 100Hz frequency with this method.

Identical phase oscillators with global sinusoidal coupling evolve by Mobius group action.

Science.gov (United States)

Marvel, Seth A; Mirollo, Renato E; Strogatz, Steven H

2009-12-01

Systems of N identical phase oscillators with global sinusoidal coupling are known to display low-dimensional dynamics. Although this phenomenon was first observed about 20 years ago, its underlying cause has remained a puzzle. Here we expose the structure working behind the scenes of these systems by proving that the governing equations are generated by the action of the Mobius group, a three-parameter subgroup of fractional linear transformations that map the unit disk to itself. When there are no auxiliary state variables, the group action partitions the N-dimensional state space into three-dimensional invariant manifolds (the group orbits). The N-3 constants of motion associated with this foliation are the N-3 functionally independent cross ratios of the oscillator phases. No further reduction is possible, in general; numerical experiments on models of Josephson junction arrays suggest that the invariant manifolds often contain three-dimensional regions of neutrally stable chaos.

Amelioration of cirrhotic portal hypertension by targeted cyclooxygenase-1 siRNA delivery to liver sinusoidal endothelium with polyethylenimine grafted hyaluronic acid.

Science.gov (United States)

Lin, Liteng; Cai, Mingyue; Deng, Shaohui; Huang, Wensou; Huang, Jingjun; Huang, Xinghua; Huang, Mingsheng; Wang, Yong; Shuai, Xintao; Zhu, Kangshun

2017-10-01

Portal hypertension (PH), a leading cause of mortality in cirrhosis, lacks effective clinical therapeutic strategies. The increased thromboxane A 2 (TXA 2 ), derived primarily from the upregulation of cyclooxygenase-1 (COX-1) in cirrhotic liver sinusoidal endothelial cells (LSECs), is responsible for hepatic endothelial dysfunction and PH. Thus, blocking the COX-1 pathway in cirrhotic LSECs may benefit the treatment of PH. In this study, hyaluronate-graft-polyethylenimine (HA-PEI) was synthesized for the targeted delivery of COX-1 siRNA to LSECs. Compared to non-targeted PEI, HA-PEI mediated much more efficient siRNA delivery, which resulted in potent targeted gene silencing in LSECs. In vivo, HA-PEI notably increased the accumulation of siRNA along the sinusoidal lining of the liver, inhibited over-activation of the COX-1/TXA 2 pathway in LSECs, and successfully reduced portal pressure in cirrhotic mice. These results highlight the potential of HA-PEI complexed siRNA to serve as a LSECs-specific nanomedical system for effective gene therapy in PH. Copyright © 2017 Elsevier Inc. All rights reserved.

"Pre-emptive strike"-the case for early treatment of hepatic sinusoidal obstruction syndrome with defibrotide.

Science.gov (United States)

Rajagopal, Revathi; Phillips, Marianne B; Gottardo, Nicholas G

2018-07-01

The initial signs of hepatic sinusoidal obstruction syndrome (HSOS) can be challenging to recognize in children, especially outside the hematopoietic stem cell transplantation setting. To assist clinicians to promptly identify HSOS, the European Society for Blood and Marrow Transplantation has proposed pediatric HSOS diagnostic criteria which emphasize unexplained consumptive and transfusion-refractory thrombocytopenia. To highlight the importance of these "bellwether" early signs of HSOS and the efficacy of pre-emptive treatment with defibrotide, we describe the case of a child with a right 11th rib primitive neuroectodermal tumor who developed HSOS following focal radiotherapy and actinomycin-D treatment. © 2018 The Authors. Pediatric Blood & Cancer Published by Wiley Periodicals, Inc.

Time-frequency analyses of fluid-solid interaction under sinusoidal translational shear deformation of the viscoelastic rat cerebrum

Science.gov (United States)

Leahy, Lauren N.; Haslach, Henry W.

2018-02-01

During normal extracellular fluid (ECF) flow in the brain glymphatic system or during pathological flow induced by trauma resulting from impacts and blast waves, ECF-solid matter interactions result from sinusoidal shear waves in the brain and cranial arterial tissue, both heterogeneous biological tissues with high fluid content. The flow in the glymphatic system is known to be forced by pulsations of the cranial arteries at about 1 Hz. The experimental shear stress response to sinusoidal translational shear deformation at 1 Hz and 25% strain amplitude and either 0% or 33% compression is compared for rat cerebrum and bovine aortic tissue. Time-frequency analyses aim to correlate the shear stress signal frequency components over time with the behavior of brain tissue constituents to identify the physical source of the shear nonlinear viscoelastic response. Discrete fast Fourier transformation analysis and the novel application to the shear stress signal of harmonic wavelet decomposition both show significant 1 Hz and 3 Hz components. The 3 Hz component in brain tissue, whose magnitude is much larger than in aortic tissue, may result from interstitial fluid induced drag forces. The harmonic wavelet decomposition locates 3 Hz harmonics whose magnitudes decrease on subsequent cycles perhaps because of bond breaking that results in easier fluid movement. Both tissues exhibit transient shear stress softening similar to the Mullins effect in rubber. The form of a new mathematical model for the drag force produced by ECF-solid matter interactions captures the third harmonic seen experimentally.

Dynamics of the Josephson multi-junction system with junctions characterized by non-sinusoidal current - phase relationship

International Nuclear Information System (INIS)

Abal'osheva, I.; Lewandowski, S.J.

2004-01-01

It is shown that the inclusion of junctions characterized by non-sinusoidal current - phase relationship in the systems composed of multiple Josephson junctions - results in the appearance of additional system phase states. Numerical simulations and stability considerations confirm that those phase states can be realized in practice. Moreover, spontaneous formation of the grain boundary junctions in high-T c superconductors with non-trivial current-phase relations due to the d-wave symmetry of the order parameter is probable. Switching between the phase states of multiple grain boundary junction systems can lead to additional 1/f noise in high-T c superconductors. (author)

Updates to Post-Flash Calibration for the Advanced Camera for Surveys Wide Field Channel

Science.gov (United States)

Miles, Nathan

2018-03-01

This report presents a new technique for generating the post-flash calibration reference file for the Advanced Camera for Surveys (ACS) Wide Field Channel (WFC). The new method substantially reduces, if not, eliminates all together the presence of dark current artifacts arising from improper dark subtraction, while simultaneously preserving flat-field artifacts. The stability of the post-flash calibration reference file over time is measured using data taken yearly since 2012 and no statistically significant deviations are found. An analysis of all short-flashed darks taken every two days since January 2015 reveals a periodic modulation of the LED intensity on timescales of about one year. This effect is most readily explained by changes to the local temperature in the area surrounding the LED. However, a slight offset between the periods of the temperature and LED modulations lends to the possibility that the effect is a chance observation of the two sinusoids at an unfortunate point in their beat cycle.

Sinusoidal obstruction syndrome (veno-occlusive disease in a patient receiving bevacizumab for metastatic colorectal cancer: a case report

Directory of Open Access Journals (Sweden)

Agarwal Vijay

2008-07-01

Full Text Available Abstract Introduction We present the case of a patient with colon cancer who, while receiving bevacizumab, developed sinusoidal obstruction syndrome (veno-occlusive disease (SOSVOD. Certain antitumour agents such as 6-mercaptopurine and 6-thioguanine have also been reported to initiate hepatic SOSVOD in isolated cases. There have been no reports so far correlating bevacizumab with SOSVOD. Case presentation A 77-year-old man was being treated with oxaliplatin and a modified de Gramont regimen of 5-fluorouracil for metastatic colon cancer. Bevacizumab (7.5 mg/kg was added from the seventh cycle onwards. Protracted neutropenia and thrombocytopenia led to discontinuation of oxaliplatin after the ninth cycle. A computed tomography scan showed complete response and bevacizumab was continued for another 3 months, after which time the patient developed right hypochondrial pain, transudative ascites, splenomegaly and abnormal liver function tests. Upper gastrointestinal endoscopy showed oesophageal varices. Liver biopsy showed features considered to be consistent with SOSVOD. Bevacizumab was stopped and a policy of watchful waiting was adopted. He tolerated the acute damage to his liver and subsequently the ascites resolved and liver function tests normalised. Conclusion We need to be aware that bevacizumab can cause sinusoidal obstruction syndrome (veno-occlusive disease and that the occurrence of ascites should not be attributed to progressive disease without appropriate evaluation.

Tissue responses to fractional transient heating with sinusoidal heat flux condition on skin surface.

Science.gov (United States)

Ezzat, Magdy A; El-Bary, Alaa A; Al-Sowayan, Noorah S

2016-10-01

A fractional model of Bioheat equation for describing quantitatively the thermal responses of skin tissue under sinusoidal heat flux conditions on skin surface is given. Laplace transform technique is used to obtain the solution in a closed form. The resulting formulation is applied to one-dimensional application to investigate the temperature distribution in skin with instantaneous surface heating for different cases. According to the numerical results and its graphs, conclusion about the fractional bioheat transfer equation has been constructed. Sensitivity analysis is performed to explore the thermal effects of various control parameters on tissue temperature. The comparisons are made with the results obtained in the case of the absence of time-fractional order. © 2016 Japanese Society of Animal Science. © 2016 Japanese Society of Animal Science.

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Author Details. Journal Home > Advanced Search > Author Details. Log in or Register to get access to full text downloads. ... Abstract PDF · Vol 3, No 6 (2011) - Articles Mixed convection flow and heat transfer in a vertical wavy channel containing porous and fluid layer with traveling thermal waves. Abstract PDF · Vol 3, No 8 ...

Broadband frequency and angular response of a sinusoidal bull’s eye antenna

Science.gov (United States)

Beaskoetxea, U.; Navarro-Cía, M.; Beruete, M.

2016-07-01

A thorough experimental study of the frequency and beaming angle response of a metallic leaky-wave bull’s eye antenna working at 77 GHz with a sinusoidally corrugated profile is presented. The beam scanning property of these antennas as frequency is varied is experimentally demonstrated and corroborated through theoretical and numerical results. From the experimental results the dispersion diagram of the n  =  -1 and n  =  -2 space harmonics is extracted, and the operation at different frequency regimes is identified and discussed. In order to show the contribution of each half of the antenna, numerical examples of the near-field behavior are also displayed. Overall, experimental results are in good qualitative and quantitative agreement with theoretical and numerical calculations. Finally, an analysis of the beamwidth as a function of frequency is performed, showing that it can achieve values below 1.5° in a fractional bandwidth of 4% around the operation frequency, which is an interesting frequency-stable broadside radiation.

Iron losses evaluation in soft magnetic materials with a sinusoidal voltage supply

DEFF Research Database (Denmark)

Nedelcu, Steluţa; Ritchie, Ewen; Leban, Krisztina Monika

2013-01-01

This paper presents an evaluation method of for specific iron losses in non-oriented laminated steel suitable for electric motors and transformers in the case of a sinusoidal excitation. The model is based on the separation of loss contribution due to hysteresis, eddy currents and excess losses...... (between 0.35 mm and 0.65 mm) and alloy compositions. Hysteresis and eddy currents loss coefficients have been considered as dependent on the frequency. For curve fitting of these coefficients third and fourth polynomials were employed, with good result for all the frequencies and magnetic flux density...... and it is proposing an identification procedure for the model coefficients from multi-frequency single sheet tests. The frequencies used are in the range 10 Hz and 150 Hz and with the values of magnetic flux density in the range 0.1 T and 1.4 T. The model was applied on six magnetic materials of different thicknesses...

Sensorless Sinusoidal Drives for Fan and Pump Motors by V/f Control

Science.gov (United States)

Kiuchi, Mitsuyuki; Ohnishi, Tokuo

This paper proposes sensorless sinusoidal driving methods of permanent magnet synchronous motors for fans and pumps by V/f control. The proposed methods are simple methods that control the motor peak current constant by voltage or frequency control, and are characterized by DC link current detection using a single shunt resistor at carrier wave signal bottom timing. As a result of the dumping factor from square torque load characteristics of fan and pump motors, it is possible to control stable starting and stable steady state by V/f control. In general, pressure losses as a result of the fluid pass of fan and pump systems are nearly constant; therefore, the flow rate and motor torque are determined by revolutions. Accordingly, high efficiency driving is possible by setting corresponding currents to q-axis currents (torque currents) at target revolutions. Because of the simple current detection and motor control methods, the proposed methods are optimum for fan and pump motor driving systems of home appliances.

Sinusoidal Parameter Estimation Using Quadratic Interpolation around Power-Scaled Magnitude Spectrum Peaks

Directory of Open Access Journals (Sweden)

Kurt James Werner

2016-10-01

Full Text Available The magnitude of the Discrete Fourier Transform (DFT of a discrete-time signal has a limited frequency definition. Quadratic interpolation over the three DFT samples surrounding magnitude peaks improves the estimation of parameters (frequency and amplitude of resolved sinusoids beyond that limit. Interpolating on a rescaled magnitude spectrum using a logarithmic scale has been shown to improve those estimates. In this article, we show how to heuristically tune a power scaling parameter to outperform linear and logarithmic scaling at an equivalent computational cost. Although this power scaling factor is computed heuristically rather than analytically, it is shown to depend in a structured way on window parameters. Invariance properties of this family of estimators are studied and the existence of a bias due to noise is shown. Comparing to two state-of-the-art estimators, we show that an optimized power scaling has a lower systematic bias and lower mean-squared-error in noisy conditions for ten out of twelve common windowing functions.

Locomotion of Paramecium in patterned environments

Science.gov (United States)

Park, Eun-Jik; Eddins, Aja; Kim, Junil; Yang, Sung; Jana, Saikat; Jung, Sunghwan

2011-10-01

Ciliary organisms like Paramecium Multimicronucleatum locomote by synchronized beating of cilia that produce metachronal waves over their body. In their natural environments they navigate through a variety of environments especially surfaces with different topology. We study the effects of wavy surfaces patterned on the PDMS channels on the locomotive abilities of Paramecium by characterizing different quantities like velocity amplitude and wavelength of the trajectories traced. We compare this result with the swimming characteristics in straight channels and draw conclusions about the effects of various patterned surfaces.

The Effect of Welding Energy on the Microstructural and Mechanical Properties of Ultrasonic-Welded Copper Joints

Science.gov (United States)

Yang, Jingwei; Cao, Biao; Lu, Qinghua

2017-01-01

The effects of welding energy on the mechanical and microstructural characteristics of ultrasonic-welded pure copper plates were investigated. Complex dynamic recrystallization and grain growth occurred inside the weld zone during ultrasonic welding. At a low welding energy, a thin band of straight weld interfaces was observed and had an ultra-fine grain structure. With an increase in welding energy, the weld interface progressively changed from flat to sinusoidal, and eventually turned into a convoluted wavy pattern, bearing similarities to shear instabilities, as observed in fluid dynamics. The lap shear load of the joints initially increased and then remained stable as the welding energy increased. The tensile characteristics of the joints significantly depended on the development of plastic deformation at the interface. The influence of the microstructure on the hardness was also discussed. PMID:28772553

Three dimensional (3D) microstructure-based finite element modeling of Al-SiC nanolaminates using focused ion beam (FIB) tomography

Energy Technology Data Exchange (ETDEWEB)

Mayer, Carl R. [Materials Science and Engineering, Arizona State University, Tempe, AZ 85287-6106 (United States); Molina-Aladareguia, Jon [IMDEA Materials Institute, c/Eric Kandel 2, Getafe, Madrid 28906 (Spain); Chawla, Nikhilesh, E-mail: nchawla@asu.edu [Materials Science and Engineering, Arizona State University, Tempe, AZ 85287-6106 (United States)

2016-10-15

Al-SiC nanolaminate composites show promise as high performance coating materials due to their combination of strength and toughness. Although a significant amount of modeling effort has been focused on materials with an idealized flat nanostructure, experimentally these materials exhibit complex undulating layer geometries. This work utilizes FIB tomography to characterize this nanostructure in 3D and finite element modeling to determine the effect that this complex structure has on the mechanical behavior of these materials. A sufficiently large volume was characterized such that a 1 × 2 μm micropillar could be generated from the dataset and compared directly to experimental results. The mechanical response from this nanostructure was then compared to pillar models using simplified structures with perfectly flat layers, layers with sinusoidal waviness, and layers with arc segment waviness. The arc segment based layer geometry showed the best agreement with the experimentally determined structure, indicating it would be the most appropriate geometry for future modeling efforts. - Highlights: •FIB tomography was used to determine the structure of an Al-SiC nanolaminate in 3D. •FEM was used to compare the deformation of the nanostructure to experimental results. •Idealized structures from literature were compared to the FIB determined structure. •Arc segment based structures approximated the FIB determined structure most closely.

Subthreshold membrane potential oscillations in inferior olive neurons are dynamically regulated by P/Q- and T-type calcium channels: a study in mutant mice.

Science.gov (United States)

Choi, Soonwook; Yu, Eunah; Kim, Daesoo; Urbano, Francisco J; Makarenko, Vladimir; Shin, Hee-Sup; Llinás, Rodolfo R

2010-08-15

The role of P/Q- and T-type calcium channels in the rhythmic oscillatory behaviour of inferior olive (IO) neurons was investigated in mutant mice. Mice lacking either the CaV2.1 gene of the pore-forming alpha1A subunit for P/Q-type calcium channel, or the CaV3.1 gene of the pore-forming alpha1G subunit for T-type calcium channel were used. In vitro intracellular recording from IO neurons reveals that the amplitude and frequency of sinusoidal subthreshold oscillations (SSTOs) were reduced in the CaV2.1-/- mice. In the CaV3.1-/- mice, IO neurons also showed altered patterns of SSTOs and the probability of SSTO generation was significantly lower (15%, 5 of 34 neurons) than that of wild-type (78%, 31 of 40 neurons) or CaV2.1-/- mice (73%, 22 of 30 neurons). In addition, the low-threshold calcium spike and the sustained endogenous oscillation following rebound potentials were absent in IO neurons from CaV3.1-/- mice. Moreover, the phase-reset dynamics of oscillatory properties of single neurons and neuronal clusters in IO were remarkably altered in both CaV2.1-/- and CaV3.1-/- mice. These results suggest that both alpha1A P/Q- and alpha1G T-type calcium channels are required for the dynamic control of neuronal oscillations in the IO. These findings were supported by results from a mathematical IO neuronal model that incorporated T and P/Q channel kinetics.

Sinusoidal Wave Estimation Using Photogrammetry and Short Video Sequences

Directory of Open Access Journals (Sweden)

Ewelina Rupnik

2015-12-01

Full Text Available The objective of the work is to model the shape of the sinusoidal shape of regular water waves generated in a laboratory flume. The waves are traveling in time and render a smooth surface, with no white caps or foam. Two methods are proposed, treating the water as a diffuse and specular surface, respectively. In either case, the water is presumed to take the shape of a traveling sine wave, reducing the task of the 3D reconstruction to resolve the wave parameters. The first conceived method performs the modeling part purely in 3D space. Having triangulated the points in a separate phase via bundle adjustment, a sine wave is fitted into the data in a least squares manner. The second method presents a more complete approach for the entire calculation workflow beginning in the image space. The water is perceived as a specular surface, and the traveling specularities are the only observations visible to the  cameras, observations that are notably single image. The depth ambiguity is removed given additional constraints encoded within the law of reflection and the modeled parametric surface. The observation and constraint equations compose a single system of equations that is solved with the method of least squares adjustment. The devised approaches are validated against the data coming from a capacitive level sensor and on physical targets floating on the surface. The outcomes agree to a high degree.

Oscillating flow and heat transfer in a channel with sudden cross section change

Science.gov (United States)

Ibrahim, Mounir; Hashim, Waqar

1993-01-01

We have computationally examined oscillating flow (zero mean) between two parallel plates with a sudden change in cross section. The flow was assumed to be laminar incompressible with the inflow velocity uniform over the channel cross section but varying sinusoidally with time. The cases studied cover wide ranges of Re(sub max) (from 187.5 to 2000), Va (from 1 to 10.66), the expansion ratio (1:2 and 1:4) and A(sub r) (2 and 4). Also, three different geometric cases were discussed: (1) asymmetric expansion/contraction; (2) symmetric expansion/contraction; and (3) symmetric blunt body. For these oscillating flow conditions, the fluid undergoes sudden expansion in one-half of the cycle and sudden contraction inthe other half. The instantaneous friction factor, for some ranges of Re(sub max) and Va, deviated substantially from the steady-state friction factor for the same flow parameters. A region has been identified below which the flow is laminar quasi-steady. A videotape showing computer simulations of the oscillating flow demonstrates the usefulness of the current analyses in providing information on the transient hydraulic phenomena.

Sinusoidal potential cycling operation of a direct ethanol fuel cell to improving carbon dioxide yields

Science.gov (United States)

Majidi, Pasha; Pickup, Peter G.

2014-12-01

A direct ethanol fuel cell has been operated under sinusoidal (AC) potential cycling conditions in order to increase the yield of carbon dioxide and thereby increase cell efficiency relative to operation at a fixed potential. At 80 °C, faradaic yields of CO2 as high as 25% have been achieved with a PtRu anode catalyst, while the maximum CO2 production at constant potential was 13%. The increased yields under cycling conditions have been attributed to periodic oxidative stripping of adsorbed CO. These results will be important in the optimization of operating conditions for direct ethanol fuel cells, where the benefits of potential cycling are projected to increase as catalysts that produce CO2 more efficiently are implemented.

Broadband frequency and angular response of a sinusoidal bull’s eye antenna

International Nuclear Information System (INIS)

Beaskoetxea, U; Beruete, M; Navarro-Cía, M

2016-01-01

A thorough experimental study of the frequency and beaming angle response of a metallic leaky-wave bull’s eye antenna working at 77 GHz with a sinusoidally corrugated profile is presented. The beam scanning property of these antennas as frequency is varied is experimentally demonstrated and corroborated through theoretical and numerical results. From the experimental results the dispersion diagram of the n   =  −1 and n   =  −2 space harmonics is extracted, and the operation at different frequency regimes is identified and discussed. In order to show the contribution of each half of the antenna, numerical examples of the near-field behavior are also displayed. Overall, experimental results are in good qualitative and quantitative agreement with theoretical and numerical calculations. Finally, an analysis of the beamwidth as a function of frequency is performed, showing that it can achieve values below 1.5° in a fractional bandwidth of 4% around the operation frequency, which is an interesting frequency-stable broadside radiation. (paper)

Exponential sinusoidal model for predicting temperature inside underground wine cellars from a Spanish region

Energy Technology Data Exchange (ETDEWEB)

Mazarron, Fernando R.; Canas, Ignacio [Departamento de Construccion y Vias Rurales, Escuela Tecnica Superior de Ingenieros Agronomos, Universidad Politecnica de Madrid, Avda. Complutense s/n, 28040 Madrid (Spain)

2008-07-01

This article develops a mathematical model for determining the annual cycle of air temperature inside traditional underground wine cellars in the Spanish region of ''Ribera del Duero'', known because of the quality of its wines. It modifies the sinusoidal analytical model for soil temperature calculation. Results obtained when contrasting the proposed model with experimental data of three subterranean wine cellars for 2 years are satisfactory. The RMSE is below 1 C and the index of agreement is above 0.96 for the three cellars. When using the average of experimental data corresponding to the 2 years' time, results improve noticeably: the RMSE decreases by more than 30% and the mean d reaches 0.99. This model should be a useful tool for designing underground wine cellars making the most of soil energy advantages. (author)

Defibrotide in Severe Sinusoidal Obstruction Syndrome: Medicine and Economic Issues.

Science.gov (United States)

Steelandt, Julie; Bocquet, François; Cordonnier, Anne-Laure; De Courtivron, Charlotte; Fusier, Isabelle; Paubel, Pascal

2017-02-01

In Europe, Defitelio (defibrotide) has a Market Authorization in curative treatment of severe sinusoidal obstruction syndrome (SOS) but not in prophylaxis (2013). In France, defibrotide has had a compassionate-use program since 2009. Today, the high cost of defibrotide remains a major hurdle for hospital budgets. Medicine and economic issues were evaluated for the 39 hospitals of the French Public Assistance-Hospitals of Paris (AP-HP). We analyzed literature reviews, consumption, and expenditures through AP-HP data in 2014 and patient profiles with defibrotide in the corresponding diagnostic-related groups (DRGs) and consulted a board of hematologists. Finally, 18 publications were selected. Between 2011 and 2014 consumption increased to €5.2M. In 2014, 80 patients receiving defibrotide were mainly ascribed to the DRG "hematopoietic stem cell transplantation" levels 3 or 4. The tariffs attributed to drugs (€3544 to 4084) cover a small part of treatment costs (€97,524 for an adult). French experts thus recommended a harmonization of indications in prophylaxis (off-label use), improvement of pretransplant care, and optimization of the number of vials used. The economic impact led experts to change their practices. They recommended the restriction of defibrotide use to SOS curative treatment and to high-risk situations in prophylaxis. Copyright © 2017 The American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

Sinusoidal visuomotor tracking: intermittent servo-control or coupled oscillations?

Science.gov (United States)

Russell, D M; Sternad, D

2001-12-01

In visuomotor tasks that involve accuracy demands, small directional changes in the trajectories have been taken as evidence of feedback-based error corrections. In the present study variability, or intermittency, in visuomanual tracking of sinusoidal targets was investigated. Two lines of analyses were pursued: First, the hypothesis that humans fundamentally act as intermittent servo-controllers was re-examined, probing the question of whether discontinuities in the movement trajectory directly imply intermittent control. Second, an alternative hypothesis was evaluated: that rhythmic tracking movements are generated by entrainment between the oscillations of the target and the actor, such that intermittency expresses the degree of stability. In 2 experiments, participants (N = 6 in each experiment) swung 1 of 2 different hand-held pendulums, tracking a rhythmic target that oscillated at different frequencies with a constant amplitude. In 1 line of analyses, the authors tested the intermittency hypothesis by using the typical kinematic error measures and spectral analysis. In a 2nd line, they examined relative phase and its variability, following analyses of rhythmic interlimb coordination. The results showed that visually guided corrective processes play a role, especially for slow movements. Intermittency, assessed as frequency and power components of the movement trajectory, was found to change as a function of both target frequency and the manipulandum's inertia. Support for entrainment was found in conditions in which task frequency was identical to or higher than the effector's eigenfrequency. The results suggest that it is the symmetry between task and effector that determines which behavioral regime is dominant.

Cyclic steps and superimposed antidune deposits: important elements of coarse-grained deepwater channel-levée complexes

Science.gov (United States)

Lang, Joerg; Brandes, Christian; Winsemann, Jutta

2017-04-01

The facies distribution and architecture of submarine fans can be strongly impacted by erosion and deposition by supercritical density flows. We present field examples from the Sandino Forearc Basin (southern Central America), where cyclic-step and antidune deposits represent important sedimentary facies of coarse-grained channel-levée complexes. These bedforms occur in all sub-environments of the depositional systems and relate to the different stages of avulsion, bypass, levée construction and channel backfilling. Large-scale scours (18 to 29 m deep, 18 to 25 m wide, 60 to >120 m long) with an amalgamated infill, comprising massive, normally coarse-tail graded or spaced subhorizontally stratified conglomerates and pebbly sandstones, are interpreted as deposits of the hydraulic-jump zone of cyclic steps. These cyclic steps probably formed during avulsion, when high-density flows were routed into the evolving channel. The large-scale scour fills can be distinguished from small-scale channel fills based on the preservation of a steep upper margin and a coarse-grained infill comprising mainly amalgamated hydraulic-jump deposits. Channel fills include repetitive successions deposited by cyclic steps with superimposed antidunes. The hydraulic-jump zone of cyclic-step deposits comprises regularly spaced scours (0.2 to 2.6 m deep, 0.8 to 23 m wide), which are infilled by intraclast-rich conglomerates or pebbly sandstones and display normal coarse-tail grading or backsets. Laterally and vertically these deposits are associated with subhorizontally stratified, low-angle cross-stratified or sinusoidal stratified pebbly sandstones and sandstones (wavelength 0.5 to 18 m), interpreted as representing antidune deposits formed on the stoss-side of the cyclic steps during flow re-acceleration. The field examples indicate that so-called crudely or spaced stratified deposits may commonly represent antidune deposits with varying stratification styles controlled by the aggradation

Phase-locking and chaos in a silent Hodgkin-Huxley neuron exposed to sinusoidal electric field

International Nuclear Information System (INIS)

Che Yanqiu; Wang Jiang; Si Wenjie; Fei Xiangyang

2009-01-01

Neuronal firing patterns are related to the information processing in neural system. This paper investigates the response characteristics of a silent Hodgkin-Huxley neuron to the stimulation of externally-applied sinusoidal electric field. The neuron exhibits both p:q phase-locked (i.e. a periodic oscillation defined as p action potentials generated by q cycle stimulations) and chaotic behaviors, depending on the values of stimulus frequencies and amplitudes. In one-parameter space, a rich bifurcation structure including period-adding without chaos and phase-locking alternated with chaos suggests frequency discrimination of the neuronal firing patterns. Furthermore, by mapping out Arnold tongues, we partition the amplitude-frequency parameter space in terms of the qualitative behaviors of the neuron. Thus the neuron's information (firing patterns) encodes the stimulus information (amplitude and frequency), and vice versa

Channelling and electromagnetic radiation of channelling particles

International Nuclear Information System (INIS)

Kalashnikov, N.

1983-01-01

A brief description is presented of the channelling of charged particles between atoms in the crystal lattice. The specificities are discussed of the transverse motion of channelling particles as are the origin and properties of quasi-characteristic radiation of channelling particles which accompany transfers from one band of permissible energies of the transverse motion of channelling particles to the other. (B.S.)

Neuronal oscillations with non-sinusoidal morphology produce spurious phase-to-amplitude coupling and directionality.

Directory of Open Access Journals (Sweden)

Diego Lozano-Soldevilla

2016-08-01

Full Text Available Neuronal oscillations support cognitive processing. Modern views suggest that neuronal oscillations do not only reflect coordinated activity in spatially distributed networks, but also that there is interaction between the oscillations at different frequencies. For example, invasive recordings in animals and humans have found that the amplitude of fast oscillations (> 40 Hz occur non-uniformly within the phase of slower oscillations, forming the so-called cross-frequency coupling (CFC. However, the CFC patterns be influenced by features in the signal that do not relate to underlying physiological interactions. For example, CFC estimates may be sensitive to spectral correlations due to non-sinusoidal properties of the alpha band wave morphology. To investigate this issue, we performed CFC analysis using experimental and synthetic data. The former consisted in a double-blind magnetoencephalography pharmacological study in which participants received either placebo, 0.5 mg or 1.5 mg of lorazepam (LZP; GABAergic enhancer in different experimental sessions. By recording oscillatory brain activity with during rest and working memory (WM, we were able to demonstrate that posterior alpha (8 – 12 Hz phase was coupled to beta-low gamma band (20 – 45 Hz amplitude envelope during all sessions. Importantly, bicoherence values around the harmonics of the alpha frequency were similar both in magnitude and topographic distribution to the cross-frequency coherence (CFCoh values observed in the alpha-phase to beta-low gamma coupling. In addition, despite the large CFCoh we found no significant cross-frequency directionality (CFD. Critically, simulations demonstrated that a sizable part of our empirical CFCoh between alpha and beta-low gamma coupling and the lack of CFD could be explained by two-three harmonics aligned in zero phase-lag produced by the physiologically characteristic alpha asymmetry in the amplitude of the peaks relative to the troughs

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

International Nuclear Information System (INIS)

Errasti Cabrera, Michel

2015-01-01

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

Can large-scale oblique undulations on a solid wall reduce the turbulent drag?

Science.gov (United States)

Ghebali, Sacha; Chernyshenko, Sergei I.; Leschziner, Michael A.

2017-10-01

Direct numerical simulations of fully developed turbulent channel flows with wavy walls are undertaken. The wavy walls, skewed with respect to the mean flow direction, are introduced as a means of emulating a Spatial Stokes Layer (SSL) induced by in-plane wall motion. The transverse shear strain above the wavy wall is shown to be similar to that of a SSL, thereby affecting the turbulent flow and leading to a reduction in the turbulent skin-friction drag. However, some important differences with respect to the SSL case are brought to light too. In particular, the phase variations of the turbulent properties are accentuated and, unlike in the SSL case, there is a region of increased turbulence production over a portion of the wall, above the leeward side of the wave, thus giving rise to a local increase in dissipation. The pressure- and friction-drag levels are carefully quantified for various flow configurations, exhibiting a combined maximum overall-drag reduction of about 0.6%. The friction-drag reduction is shown to behave approximately quadratically for small wave slopes and then linearly for higher slopes, whilst the pressure-drag penalty increases quadratically. The transverse shear-strain layer is shown to be approximately Reynolds-number independent when the wave geometry is scaled in wall units.

An Effective Channel Allocation Scheme to Reduce Co-Channel and Adjacent Channel Interference for WMN Backhaul

International Nuclear Information System (INIS)

Abbasi, S.; Ismaili, I.A.; Khuhawar, F.Y.

2016-01-01

Two folded work presents channel allocation scheme sustaining channel orthogonality and channel spacing to reduce CCI (Co-Channel Interference) and ACI (Adjacent Channel Interference) for inter flow of an intra-flow link. Proposed scheme as a part of radio resource allocation is applied on infrastructure based backhaul of wireless mesh network using directional antennas. The proposed approach is applied separately on 2.4 and 5GHz bands. Interference of connectivity graph is modelled by strongly connected directed graph and greedy algorithms are used for channel allocation. We have used OPNET Modeller suite to simulate network models for this research. The proposed arrangement reduces the channel interference and increases system throughput. In this research, the influence of channel is computed in terms of network throughput and delay. (author)

Scattering of atoms by a stationary sinusoidal hard wall: Rigorous treatment in (n+1) dimensions and comparison with the Rayleigh method

International Nuclear Information System (INIS)

Goodman, F.O.

1977-01-01

A rigorous treatment of the scattering of atoms by a stationary sinusoidal hard wall in (n+1) dimensions is presented, a previous treatment by Masel, Merrill, and Miller for n=1 being contained as a special case. Numerical comparisons are made with the GR method of Garcia, which incorporates the Rayleigh hypothesis. Advantages and disadvantages of both methods are discussed, and it is concluded that the Rayleigh GR method, if handled properly, will probably work satisfactorily in physically realistic cases

The evaluation of distributed damage in concrete based on sinusoidal modeling of the ultrasonic response.

Science.gov (United States)

Sepehrinezhad, Alireza; Toufigh, Vahab

2018-05-25

Ultrasonic wave attenuation is an effective descriptor of distributed damage in inhomogeneous materials. Methods developed to measure wave attenuation have the potential to provide an in-site evaluation of existing concrete structures insofar as they are accurate and time-efficient. In this study, material classification and distributed damage evaluation were investigated based on the sinusoidal modeling of the response from the through-transmission ultrasonic tests on polymer concrete specimens. The response signal was modeled as single or the sum of damping sinusoids. Due to the inhomogeneous nature of concrete materials, model parameters may vary from one specimen to another. Therefore, these parameters are not known in advance and should be estimated while the response signal is being received. The modeling procedure used in this study involves a data-adaptive algorithm to estimate the parameters online. Data-adaptive algorithms are used due to a lack of knowledge of the model parameters. The damping factor was estimated as a descriptor of the distributed damage. The results were compared in two different cases as follows: (1) constant excitation frequency with varying concrete mixtures and (2) constant mixture with varying excitation frequencies. The specimens were also loaded up to their ultimate compressive strength to investigate the effect of distributed damage in the response signal. The results of the estimation indicated that the damping was highly sensitive to the change in material inhomogeneity, even in comparable mixtures. In addition to the proposed method, three methods were employed to compare the results based on their accuracy in the classification of materials and the evaluation of the distributed damage. It is shown that the estimated damping factor is not only sensitive to damage in the final stages of loading, but it is also applicable in evaluating micro damages in the earlier stages providing a reliable descriptor of damage. In addition

Flow and axial dispersion in a sinusoidal-walled tube: Effects of inertial and unsteady flows

Science.gov (United States)

Richmond, Marshall C.; Perkins, William A.; Scheibe, Timothy D.; Lambert, Adam; Wood, Brian D.

2013-12-01

In this work, we consider a sinusoidal-walled tube (a three-dimensional tube with sinusoidally-varying diameter) as a simplified conceptualization of flow in porous media. Direct numerical simulation using computational fluid dynamics (CFD) methods was used to compute velocity fields by solving the Navier-Stokes equations, and also to numerically solve the volume averaging closure problem, for a range of Reynolds numbers (Re) spanning the low-Re to inertial flow regimes, including one simulation at Re=449 for which unsteady flow was observed. The longitudinal dispersion observed for the flow was computed using a random walk particle tracking method, and this was compared to the longitudinal dispersion predicted from a volume-averaged macroscopic mass balance using the method of volume averaging; the results of the two methods were consistent. Our results are compared to experimental measurements of dispersion in porous media and to previous theoretical results for both the low-Re, Stokes flow regime and for values of Re representing the steady inertial regime. In the steady inertial regime, a power-law increase in the effective longitudinal dispersion (DL) with Re was found, and this is consistent with previous results. This rapid rate of increase is caused by trapping of solute in expansions due to flow separation (eddies). One unsteady (but non-turbulent) flow case (Re=449) was also examined. For this case, the rate of increase of DL with Re was smaller than that observed at lower Re. Velocity fluctuations in this regime lead to increased rates of solute mass transfer between the core flow and separated flow regions, thus diminishing the amount of tailing caused by solute trapping in eddies and thereby reducing longitudinal dispersion. The observed tailing was further explored through analysis of concentration skewness (third moment) and its assymptotic convergence to conventional advection-dispersion behavior (skewness = 0). The method of volume averaging was

Spline-based high-accuracy piecewise-polynomial phase-to-sinusoid amplitude converters.

Science.gov (United States)

Petrinović, Davor; Brezović, Marko

2011-04-01

We propose a method for direct digital frequency synthesis (DDS) using a cubic spline piecewise-polynomial model for a phase-to-sinusoid amplitude converter (PSAC). This method offers maximum smoothness of the output signal. Closed-form expressions for the cubic polynomial coefficients are derived in the spectral domain and the performance analysis of the model is given in the time and frequency domains. We derive the closed-form performance bounds of such DDS using conventional metrics: rms and maximum absolute errors (MAE) and maximum spurious free dynamic range (SFDR) measured in the discrete time domain. The main advantages of the proposed PSAC are its simplicity, analytical tractability, and inherent numerical stability for high table resolutions. Detailed guidelines for a fixed-point implementation are given, based on the algebraic analysis of all quantization effects. The results are verified on 81 PSAC configurations with the output resolutions from 5 to 41 bits by using a bit-exact simulation. The VHDL implementation of a high-accuracy DDS based on the proposed PSAC with 28-bit input phase word and 32-bit output value achieves SFDR of its digital output signal between 180 and 207 dB, with a signal-to-noise ratio of 192 dB. Its implementation requires only one 18 kB block RAM and three 18-bit embedded multipliers in a typical field-programmable gate array (FPGA) device. © 2011 IEEE

Citizens and service channels: channel choice and channel management implications

NARCIS (Netherlands)

Pieterson, Willem Jan

2010-01-01

The arrival of electronic channels in the 1990s has had a huge impact on governmental service delivery. The new channels have led to many new opportunities to improve public service delivery, not only in terms of citizen satisfaction, but also in cost reduction for governmental agencies. However,

Area and energy efficient high-performance ZnO wavy channel thin-film transistor

KAUST Repository

Hanna, Amir; Ghoneim, Mohamed T.; Bahabry, Rabab R.; Hussain, Aftab M.; Fahad, Hossain M.; Hussain, Muhammad Mustafa

2014-01-01

of the transistor width in the direction perpendicular to the substrate through integrating continuous fin features on the underlying substrate. This architecture enables expanding the TFT width without consuming any additional chip area, thus enabling increased

Single-channel kinetics of BK (Slo1 channels

Directory of Open Access Journals (Sweden)

Yanyan eGeng

2015-01-01

Full Text Available Single-channel kinetics has proven a powerful tool to reveal information about the gating mechanisms that control the opening and closing of ion channels. This introductory review focuses on the gating of large conductance Ca2+- and voltage-activated K+ (BK or Slo1 channels at the single-channel level. It starts with single-channel current records and progresses to presentation and analysis of single-channel data and the development of gating mechanisms in terms of discrete state Markov (DSM models. The DSM models are formulated in terms of the tetrameric modular structure of BK channels, consisting of a central transmembrane pore-gate domain (PGD attached to four surrounding transmembrane voltage sensing domains (VSD and a large intracellular cytosolic domain (CTD, also referred to as the gating ring. The modular structure and data analysis shows that the Ca2+ and voltage dependent gating considered separately can each be approximated by 10-state two-tiered models with 5 closed states on the upper tier and 5 open states on the lower tier. The modular structure and joint Ca2+ and voltage dependent gating are consistent with a 50 state two-tiered model with 25 closed states on the upper tier and 25 open states on the lower tier. Adding an additional tier of brief closed (flicker states to the 10-state or 50-state models improved the description of the gating. For fixed experimental conditions a channel would gate in only a subset of the potential number of states. The detected number of states and the correlations between adjacent interval durations are consistent with the tiered models. The examined models can account for the single-channel kinetics and the bursting behavior of gating. Ca2+ and voltage activate BK channels by predominantly increasing the effective opening rate of the channel with a smaller decrease in the effective closing rate. Ca2+ and depolarization thus activate by mainly destabilizing the closed states.

Detailed comparative study regarding different formulae of predicting the iron losses in a machine excited by non-sinusoidal supply

International Nuclear Information System (INIS)

El-Kharashi, Eyhab

2014-01-01

Variable-speed drives in any machine provide an accurate control and high-energy efficiency. More and more often machines are excited by non-sinusoidal voltages. Predicting the amount of iron losses in non-sinusoidal excitation is important. The paper aims to achieve accurate efficiency estimation by presenting a new modified calculation method to predict the iron losses. In a switched reluctance motor, the iron losses can't be ignored, it has considered value. This paper presents conventional and modified Steinmetz formulae for the estimation of the iron losses. The conventional Steinmetz formula consists of three terms: hysteresis, eddy current and anomalous losses. The equations of hysteresis and eddy current losses depend mainly on the value of the peak flux density. The reason to modify the Steinmetz formula is to avoid the need of knowing the peak flux density and the anomalous losses in accurate figures. The paper also explains and clarifies the methods of using both the conventional as well as the modified Steinmetz formulae in accurate calculation of the iron losses in different sections of the magnetic circuit. For both formulae, a comparison is made between the distributions of the iron losses in different parts of the magnetic circuit and the efficiencies. - Highlights: • The paper aims to achieve accurate efficiency estimation. • The predicted iron loss by the conventional Steinmetz formula is inaccurate. • The modified Steinmetz formula is more accurate because it includes the minor loops losses caused by each flux density. • The paper compared the predicted losses obtained by the two different formals to stand on the degree of accuracy

[Synopsis about the hypothesis of "information channel" of channel-collateral system].

Science.gov (United States)

Chang, Xi-Lang

2008-10-01

The author of the present paper founded a theorem about the "incompleteness of single channel structure" (nerve, blood vessel, lymphatic, interspace, aperture, etc.) through quantitative and qualitative analysis about the economic information channel in the human body, which eliminates the probability of single channel structure in the information channel of channel (meridian)-collateral system. After comprehensive analysis on the current researches, the author puts forward a neodoxy, i.e., the body "information channel" structure of the channel-collateral system, mainly follows the distribution regularity of systemic statistics, and is not a single specific entity; various layers of the information channel in the main stems of the channel-collaterals are composed of optimized structure tissues. Hence, the structure of this information channel of channel-collateral system is an overall-optimized, sequential and compatible systemic structure. From this neodoxy, the author brings forward a working principle of channel-collaterals, which is supported theoretically by bio-auxology. The longitudinal distribution of the main stems of meridian-collaterals is considered to result from that in the process of the animal evolution, in the animals moving forward, the microscopic complicated movement of intracorporeal information and energy molecules is related to the forward macroscopic and non-uniform movement of organism in trans-measure. Its impulse and kinetic momentum forms a main vector in the longitudinal direction of the body (the direction of the main stem of channel-collaterals). In order to adapt to and utilize natural regularities, the main stems of the channel-collaterals gradually differentiate and evolve in the living organism, forming a whole system. The "hypothesis of biological origin of channel-collateral system" and "that of information channel of the channel-collaterals in the body" constitute a relatively complete theoretical system framework.

Defibrotide sodium for the treatment of hepatic veno-occlusive disease/sinusoidal obstruction syndrome.

Science.gov (United States)

Richardson, Paul G; Triplett, Brandon M; Ho, Vincent T; Chao, Nelson; Dignan, Fiona L; Maglio, Michelle; Mohty, Mohamad

2018-02-01

Hepatic veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) is an unpredictable condition associated with endothelial-cell damage due to conditioning for hematopoietic stem-cell transplantation (HSCT) or chemotherapy without HSCT. Mortality in patients with VOD/SOS and multi-organ dysfunction (MOD) may be >80%. Areas covered: Defibrotide is the only approved drug for the treatment of severe hepatic VOD/SOS after HSCT in the European Union and hepatic VOD/SOS with renal or pulmonary dysfunction in the United States. Its efficacy in patients with VOD/SOS with MOD post-HSCT was demonstrated in a clinical-trial program that included a historically controlled treatment study, a phase 2 trial, and a large T-IND expanded-access program that also included patients without MOD and who received chemotherapy without HSCT. Expert commentary: Defibrotide appears to protect endothelial cells and restore the thrombolytic-fibrinolytic balance. It addresses a significant clinical need and has demonstrated favorable Day +100 survival and overall adverse-event rates that seem similar to control groups receiving supportive care alone. Currently, defibrotide is under investigation for the prevention of VOD/SOS in high-risk pediatric and adult patients.

Successful treatment with defibrotide for sinusoidal obstruction syndrome after hematopoietic stem cell transplantation.

Science.gov (United States)

Yakushijin, Kimikazu; Matsui, Toshimitsu; Okamura, Atsuo; Yamamoto, Katsuya; Ito, Mitsuhiro; Chihara, Kazuo

2005-01-01

Sinusoidal obstruction syndrome (SOS) (formerly known as hepatic veno-occlusive disease (VOD)) is a life-threatening complication subsequent to hematopoietic stem cell transplantation. However, no completely satisfactory strategies for the treatment of SOS have been established yet. Defibrotide is a single-stranded polydeoxyribonucleotide with anti-thrombotic, anti-ischemic, anti-inflammatory and thrombolytic properties, but without systemic anticoagulant effects, and some encouraging results have been reported in western countries. We treated four patients with defibrotide for SOS, since there seemed to be no possibility to cure the patients with conventionally available treatments in Japan. All patients showed evidence of multiple organ failure at the start of the treatment. Defibrotide was administered intravenously in normal saline in four divided doses for 14 to 27 days. Three patients (75%) responded to the therapy, while one died of SOS and cytomegalovirus infection despite intensive therapy. None of the patients suffered from significant adverse effects such as severe hemorrhage. This is the first report dealing with the treatment with defibrotide of Japanese patients with SOS. Because defibrotide is considered to be promising for the treatment of SOS, it is important to start a phase II study as soon as possible.

Investigation of secondary flows in turbulent pipe flows with three-dimensional sinusoidal walls

Science.gov (United States)

Chan, Leon; MacDonald, Michael; Chung, Daniel; Hutchins, Nicholas; Ooi, Andrew

2017-11-01

The occurrence of secondary flows is systematically investigated via Direct Numerical Simulations (DNS) of turbulent flow in a rough wall pipe at friction Reynolds numbers of 540. In this study, the peak-to-trough height of the roughness elements, which consist of three-dimensional sinusoidal roughness, is fixed at 120 viscous units while the wavelength of the roughness elements is varied. The solidity or effective slope (ES) of the roughness ranges from the sparse regime (ES = 0.18) to the closely packed roughness/dense regime (ES = 0.72). The time-independent dispersive stresses, which arise due to the stationary features of the flow, are analysed and are found to increase with increasing roughness wavelength. These dispersive stresses are related to the occurrence of secondary flows and are maximum within the roughness canopy. Above the crest of the roughness elements, the dispersive stresses reduce to zero at wall-normal heights greater than half of the roughness wavelength. This study has found that the size and wall-normal extent of the secondary flows scales with the roughness wavelength and can reach wall-normal heights of almost half of the pipe radius.

High and tunable spin current induced by magnetic-electric fields in a single-mode spintronic device

International Nuclear Information System (INIS)

Bala Kumar, S; Jalil, M B A; Tan, S G; Liang, G-C

2009-01-01

We proposed that a viable form of spin current transistor is one to be made from a single-mode device which passes electrons through a series of magnetic-electric barriers built into the device. The barriers assume a wavy spatial profile across the conduction path due to the inevitable broadening of the magnetic fields. Field broadening results in a linearly increasing vector potential across the conduction channel, which increases spin polarization. We have identified that the important factors for generating high spin polarization and conductance modulation are the low source-drain bias, the broadened magnetic fields, and the high number of FM gates within a fixed channel length.

Channel box

International Nuclear Information System (INIS)

Tanabe, Akira.

1993-01-01

In a channel box of a BWR type reactor, protruding pads are disposed in axial position on the lateral side of a channel box opposing to a control rod and facing the outer side portion of the control rod in a reactor core loaded state. In the initial loading stage of fuel assemblies, channel fasteners and spacer pads are abutted against each other in the upper portion between the channel boxes sandwiching the control rod therebetween. Further, in the lower portion, a gap as a channel for the movement of the control rod is ensured by the support of fuel support metals. If the channel box is bent toward the control rod along with reactor operation, the pads are abutted against each other to always ensure the gap through which the control rod can move easily. Further, when the pads are brought into contact with each other, the bending deformation of the channel box is corrected by urging to each other. Thus, the control rod can always be moved smoothly to attain reactor safety operation. (N.H.)

Memristors in the electrical network of Aloe vera L.

Science.gov (United States)

Volkov, Alexander G; Reedus, Jada; Mitchell, Colee M; Tucket, Clayton; Forde-Tuckett, Victoria; Volkova, Maya I; Markin, Vladislav S; Chua, Leon

2014-01-01

A memristor is a resistor with memory, which is a non-linear passive two-terminal electrical element relating magnetic flux linkage and electrical charge. Here we found that memristors exist in vivo. The electrostimulation of the Aloe vera by bipolar sinusoidal or triangle periodic waves induce electrical responses with fingerprints of memristors. Uncouplers carbonylcyanide-3-chlorophenylhydrazone and carbonylcyanide-4-trifluoromethoxy-phenyl hydrazone decrease the amplitude of electrical responses at low and high frequencies of bipolar periodic sinusoidal or triangle electrostimulating waves. Memristive behavior of an electrical network in the Aloe vera is linked to the properties of voltage gated ion channels: the K+ channel blocker TEACl reduces the electric response to a conventional resistor. Our results demonstrate that a voltage gated K+ channel in the excitable tissue of plants has properties of a memristor. The discovery of memristors in plants creates a new direction in the modeling and understanding of electrical phenomena in plants. PMID:25763487

Improvement of stability of sinusoidally driven atmospheric pressure plasma jet using auxiliary bias voltage

Directory of Open Access Journals (Sweden)

Hyun-Jin Kim

2015-12-01

Full Text Available In this study, we have proposed the auxiliary bias pulse scheme to improve the stability of atmospheric pressure plasma jets driven by an AC sinusoidal waveform excitation source. The stability of discharges can be significantly improved by the compensation of irregular variation in memory voltage due to the effect of auxiliary bias pulse. From the parametric study, such as the width, voltage, and onset time of auxiliary bias pulse, it has been demonstrated that the auxiliary bias pulse plays a significant role in suppressing the irregular discharges caused by the irregular variation in memory voltage and stable discharge can be initiated with the termination of the auxiliary bias pulse. As a result of further investigating the effects of the auxiliary pulse scheme on the jet stability under various process conditions such as the distance between the jet head and the counter electrode, and carrier gas flow, the jet stability can be improved by adjusting the amplitude and number of the bias pulse depending on the variations in the process conditions.

Effects of chronic alcoholism in the sensitivity to luminance contrast in vertical sinusoidal gratings

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Éllen Dias Nicácio da Cruz

2016-01-01

Full Text Available Abstract The aim of this study was to measure visual contrast sensitivity (CS of luminance using vertical sinusoidal gratings with spatial frequencies of 0.6, 2.5, 5.0 and 20.0 cycles per degree of visual angle in chronic alcoholics in abstinence period. The participants were 20 volunteers (26–59 years of age divided into two groups: the study group (SG consisted of 10 volunteers with a clinical history of chronic alcoholism abstinence and the control group (CG consisted of 10 healthy volunteers. Each group had five female and five male participants. All participants had normal or corrected visual acuity and were free of identifiable diseases. The psychophysical method of forced choice between two temporal alternatives (2AFC was used to measure visual CS of luminance of 41.2 cd/m2. The results showed significant differences between groups for all spatial frequencies tested (p< 0.001. These results suggest alterations in the visual perception related to chronic alcohol consumption even after years of abstinence.

Schizophrenia spectrum participants have reduced visual contrast sensitivity to chromatic (red/green and luminance (light/dark stimuli: new insights into information processing, visual channel function and antipsychotic effects

Directory of Open Access Journals (Sweden)

Kristin Suzanne Cadenhead

2013-08-01

Full Text Available Background: Individuals with schizophrenia spectrum diagnoses have deficient visual information processing as assessed by a variety of paradigms including visual backward masking, motion perception and visual contrast sensitivity (VCS. In the present study, the VCS paradigm was used to investigate potential differences in magnocellular (M versus parvocellular (P channel function that might account for the observed information processing deficits of schizophrenia spectrum patients. Specifically, VCS for near threshold luminance (black/white stimuli is known to be governed primarily by the M channel, while VCS for near threshold chromatic (red/green stimuli is governed by the P channel. Methods: VCS for luminance and chromatic stimuli (counterphase-reversing sinusoidal gratings, 1.22 c/deg, 8.3 Hz was assessed in 53 patients with schizophrenia (including 5 off antipsychotic medication, 22 individuals diagnosed with schizotypal personality disorder and 53 healthy comparison subjects. Results: Schizophrenia spectrum groups demonstrated reduced VCS in both conditions relative to normals, and there was no significant group by condition interaction effect. Post-hoc analyses suggest that it was the patients with schizophrenia on antipsychotic medication as well as SPD participants who accounted for the deficits in the luminance condition. Conclusions: These results demonstrate visual information processing deficits in schizophrenia spectrum populations but do not support the notion of selective abnormalities in the function of subcortical channels as suggested by previous studies. Further work is needed in a longitudinal design to further assess VCS as a vulnerability marker for psychosis as well as the effect of antipsychotic agents on performance in schizophrenia spectrum populations.

Treatment of sinusoidal obstruction syndrome with defibrotide: a single-center experience.

Science.gov (United States)

Sucak, G T; Aki, Z S; Yagcí, M; Yegin, Z A; Ozkurt, Z N; Haznedar, R

2007-06-01

Sinusoidal obstruction syndrome (SOS) is a frequent, troubling, and potentially fatal complication of hematopoietic stem cell transplantation. Despite promising results with defibrotide (DF), no treatment has been established as standard. DF is a single-stranded polydeoxyribonucleotide, obtained from controlled depolymerization of porcine intestinal mucosal cells. It has antithrombotic, antiischemic, antiinflammatory, and thrombolytic properties without significant side effects. We retrospectively evaluated the charts of 80 consecutive patients, with 89 hematopoietic stem cell transplants for hematologic malignancies. The results of early initiation of DF treatment in 14 patients with SOS are presented in this study. Fourteen patients, 8 males and 6 females % median age 40.5 years (range, 16-46 years) were diagnosed to have SOS. Disease severity was classified as severe in 6 (42.85%), moderate in 4 (28.57%), and mild in 4 (28.57%) patients. We treated 14 patients with DF for a median of 21.5 days (range, 4-39 days). All 14 patients received DF after the diagnosis of SOS. Three patients with severe and all of the patients with mild to moderate SOS responded to treatment with complete resolution of SOS-related signs and symptoms. All patients responding to DF were alive at 100 days posttransplantation. There was no significant drug-related side effect among patients treated with DF. With an overall response rate of 78.56% and a 50% complete response rate in severe SOS cases and minimal side effects, we suggest that DF is the best available agent to treat SOS.

Ion channeling

International Nuclear Information System (INIS)

Erramli, H.; Blondiaux, G.

1994-01-01

Channeling phenomenon was predicted, many years ago, by stark. The first channeling experiments were performed in 1963 by Davies and his coworkers. Parallely Robinson and Oen have investigated this process by simulating trajectories of ions in monocrystals. This technique has been combined with many methods like Rutherford Backscattering Spectrometry (R.B.S.), Particles Induced X-rays Emission (P.I.X.E) and online Nuclear Reaction (N.R.A.) to localize trace elements in the crystal or to determine crystalline quality. To use channeling for material characterization we need data about the stopping power of the incident particle in the channeled direction. The ratios of channeled to random stopping powers of silicon for irradiation in the direction have been investigated and compared to the available theoretical results. We describe few applications of ion channeling in the field of materials characterization. Special attention is given to ion channeling combined with Charged Particle Activation Analysis (C.P.A.A.) for studying the behaviour of oxygen atoms in Czochralski silicon lattices under the influence of internal gettering and in different gaseous atmospheres. Association between ion channeling and C.P.A.A was also utilised for studying the influence of the growing conditions on concentration and position of carbon atoms at trace levels in the MOVPE Ga sub (1-x) Al sub x lattice. 6 figs., 1 tab., 32 refs. (author)

Channel characteristics and coordination in three-echelon dual-channel supply chain

Science.gov (United States)

Saha, Subrata

2016-02-01

We explore the impact of channel structure on the manufacturer, the distributer, the retailer and the entire supply chain by considering three different channel structures in radiance of with and without coordination. These structures include a traditional retail channel and two manufacturer direct channels with and without consistent pricing. By comparing the performance of the manufacturer, the distributer and the retailer, and the entire supply chain in three different supply chain structures, it is established analytically that, under some conditions, a dual channel can outperform a single retail channel; as a consequence, a coordination mechanism is developed that not only coordinates the dual channel but also outperforms the non-cooperative single retail channel. All the analytical results are further analysed through numerical examples.

Manifestations and management of veno-occlusive disease/sinusoidal obstruction syndrome in the era of contemporary therapies.

Science.gov (United States)

Tewari, Priti; Wallis, Whitney; Kebriaei, Partow

2017-02-01

The concept of veno-occlusive disease (VOD), along with our understanding of it, has historically been and remains an evolving phenomenon. This review presents a broad view of VOD, also known as sinusoidal obstruction syndrome (SOS), including (1) traditional hematopoietic stem cell transplant-associated VOD/SOS, (2) late-onset VOD/SOS, (3) pulmonary VOD, and (4) VOD/SOS associated with chemotherapy only. Several VOD/SOS management modalities exist that include modes for both prophylaxis and treatment. An extensive review of the literature on monoclonal antibodies, both approved and pending approval by the US Food and Drug Administration, reveals that only a few have been associated with an increased risk for VOD/SOS. In fact, bevacizumab appears to have a protective effect against the development of VOD/SOS. As the landscape of cancer treatment changes, careful attention needs to be focused on how new therapies affect the incidence of VOD/SOS.

MONETARY TRANSMISSION CHANNELS IN ROMANIA – THE CREDIT CHANNEL

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Magdalena RĂDULESCU

2009-12-01

Full Text Available The theoretical – intuitive analysis applied to the segment of monetary transmission evidences the fact that forming the traditional monetary impulses transmission channels are in a starting phase due to the long financial non – intermediary process which Romanian economy had known. In these conditions, the exchange rate channel, and also NBR currency purchases was, for a long time, an important way through which monetary authorities actions influenced macro economical behaviors. But starting with 2000, it is observed a credit channel reactivation and, especially, interest rate channel. Anyhow, the credit channel continues to be undermined by the existence of liquidity surplus within the system, by the phenomena of substitution of national currency credit with currency credits, and also moral hazardous displays. Albeit some of these phenomena also affect the interest rate channel, its role in sending monetary policy impulses is in a continuous progress. Apparently, it acts by way of nominal interest rates, their real level seeming less relevant. Once with remaking the two traditional channels, the companies and households balance is configured and consolidated, which shall potentate in the future the efficiency of the monetary policy. This paper analyses the credit channel in Romania, through an unrestricted VAR analysis.. It shows the responses of exchange rate, inflation rate, GDP, interest rate, imports and exports to a shock on non-governmental credit

ZnO-channel thin-film transistors: Channel mobility

International Nuclear Information System (INIS)

Hoffman, R.L.

2004-01-01

ZnO-channel thin-film transistor (TFT) test structures are fabricated using a bottom-gate structure on thermally oxidized Si; ZnO is deposited via RF sputtering from an oxide target, with an unheated substrate. Electrical characteristics are evaluated, with particular attention given to the extraction and interpretation of transistor channel mobility. ZnO-channel TFT mobility exhibits severe deviation from that assumed by ideal TFT models; mobility extraction methodology must accordingly be recast so as to provide useful insight into device operation. Two mobility metrics, μ avg and μ inc , are developed and proposed as relevant tools in the characterization of nonideal TFTs. These mobility metrics are employed to characterize the ZnO-channel TFTs reported herein; values for μ inc as high as 25 cm2/V s are measured, comprising a substantial increase in ZnO-channel TFT mobility as compared to previously reported performance for such devices

Complexity in pH-Dependent Ribozyme Kinetics: Dark pKa Shifts and Wavy Rate-pH Profiles.

Science.gov (United States)

Frankel, Erica A; Bevilacqua, Philip C

2018-02-06

Charged bases occur in RNA enzymes, or ribozymes, where they play key roles in catalysis. Cationic bases donate protons and perform electrostatic catalysis, while anionic bases accept protons. We previously published simulations of rate-pH profiles for ribozymes in terms of species plots for the general acid and general base that have been useful for understanding how ribozymes respond to pH. In that study, we did not consider interaction between the general acid and general base or interaction with other species on the RNA. Since that report, diverse small ribozyme classes have been discovered, many of which have charged nucleobases or metal ions in the active site that can either directly interact and participate in catalysis or indirectly interact as "influencers". Herein, we simulate experimental rate-pH profiles in terms of species plots in which reverse protonated charged nucleobases interact. These analyses uncover two surprising features of pH-dependent enzyme kinetics. (1) Cooperativity between the general acid and general base enhances population of the functional forms of a ribozyme and manifests itself as hidden or "dark" pK a shifts, real pK a shifts that accelerate the reaction but are not readily observed by standard experimental approaches, and (2) influencers favorably shift the pK a s of proton-transferring nucleobases and manifest themselves as "wavy" rate-pH profiles. We identify parallels with the protein enzyme literature, including reverse protonation and wavelike behavior, while pointing out that RNA is more prone to reverse protonation. The complexities uncovered, which arise from simple pairwise interactions, should aid deconvolution of complex rate-pH profiles for RNA and protein enzymes and suggest veiled catalytic devices for promoting catalysis that can be tested by experiment and calculation.

Disguising quantum channels by mixing and channel distance trade-off

International Nuclear Information System (INIS)

Fung, Chi-Hang Fred; Chau, H F

2014-01-01

We consider the reverse problem of the distinguishability of two quantum channels, which we call the disguising problem. Given two quantum channels, the goal here is to make the two channels identical by mixing with some other channels with minimal mixing probabilities. This quantifies how much one channel can disguise as the other. In addition, the possibility to trade-off between the two mixing probabilities allows one channel to be more preserved (less mixed) at the expense of the other. We derive lower- and upper-bounds of the trade-off curve and apply them to a few example channels. Optimal trade-off is obtained in one example. We relate the disguising problem and the distinguishability problem by showing that the former can lower and upper bound the diamond norm. We also show that the disguising problem gives an upper-bound on the key generation rate in quantum cryptography. (paper)

Richtmyer-Meshkov instability of a sinusoidal interface driven by a cylindrical shock

Science.gov (United States)

Liu, L.; Ding, J.; Zhai, Z.; Luo, X.

2018-04-01

Evolution of a single-mode interface triggered by a cylindrically converging shock in a V-shaped geometry is investigated numerically using an adaptive multi-phase solver. Several physical mechanisms, including the Bell-Plesset (BP) effect, the Rayleigh-Taylor (RT) effect, the nonlinearity, and the compressibility are found to be pronounced in the converging environment. Generally, the BP and nonlinear effects play an important role at early stages, while the RT effect and the compressibility dominate the late-stage evolution. Four sinusoidal interfaces with different initial amplitudes (a_0 ) and wavelengths (λ ) are found to evolve differently in the converging geometry. For the very small a_0 /λ interfaces, nonlinearity is negligible at the early stages and the sole presence of the BP effect results in an increasing growth rate, confining the linear growth of the instability to a relatively small amount of time. For the moderately small a_0 /λ cases, the BP and nonlinear effects, which, respectively, promote and inhibit the perturbation development, coexist in the early stage. The counterbalancing effects between them produce a very long period of growth that is linear in time, even to a moment when the amplitude over wavelength ratio approaches 0.6. The RT stabilization effect at late stages due to the interface deceleration significantly inhibits the perturbation growth, which can be reasonably predicted by a modified Bell model.

Hepatic sinusoidal obstruction syndrome caused by herbal medicine: CT and MRI features

International Nuclear Information System (INIS)

Zhou, Hua; Lou, Hai Yan; Wang, Yi Xiang J.; Xu, Xiao Jun; Zhang, Min Ming

2014-01-01

To describe the CT and MRI features of hepatic sinusoidal obstruction syndrome (HSOS) caused by herbal medicine Gynura segetum. The CT and MRI features of 16 consecutive Gynura segetum induced HSOS cases (12 men, 4 women) were analyzed. Eight patients had CT; three patients had MRI, and the remaining five patients had both CT and MRI examinations. Based on their clinical presentations and outcomes, the patients were classified into three categories: mild, moderate, and severe. The severity of the disease was also evaluated radiologically based on the abnormal hepatic patchy enhancement in post-contrast CT or MRI images. Ascites, patchy liver enhancement, and main right hepatic vein narrowing or occlusion were present in all 16 cases. Hepatomegaly and gallbladder wall thickening were present in 14 cases (87.5%, 14/16). Periportal high intensity on T2-weighted images was present in 6 cases (75%, 6/8). Normal liver parenchymal enhancement surrounding the main hepatic vein forming a clover-like sign was observed in 4 cases (25%, 4/16). The extent of patchy liver enhancement was statistically associated with clinical severity classification (kappa = 0.565). Ascites, patchy liver enhancement, and the main hepatic veins narrowing were the most frequent signs of herbal medicine induced HSOS. The grade of abnormal patchy liver enhancement was associated with the clinical severity.

Hepatic sinusoidal obstruction syndrome caused by herbal medicine: CT and MRI features

Energy Technology Data Exchange (ETDEWEB)

Zhou, Hua; Lou, Hai Yan [Dept. of Radiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou (China); Wang, Yi Xiang J. [Dept. of Radiology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou (China); Xu, Xiao Jun; Zhang, Min Ming [Dept. of Radiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou (China)

2014-04-15

To describe the CT and MRI features of hepatic sinusoidal obstruction syndrome (HSOS) caused by herbal medicine Gynura segetum. The CT and MRI features of 16 consecutive Gynura segetum induced HSOS cases (12 men, 4 women) were analyzed. Eight patients had CT; three patients had MRI, and the remaining five patients had both CT and MRI examinations. Based on their clinical presentations and outcomes, the patients were classified into three categories: mild, moderate, and severe. The severity of the disease was also evaluated radiologically based on the abnormal hepatic patchy enhancement in post-contrast CT or MRI images. Ascites, patchy liver enhancement, and main right hepatic vein narrowing or occlusion were present in all 16 cases. Hepatomegaly and gallbladder wall thickening were present in 14 cases (87.5%, 14/16). Periportal high intensity on T2-weighted images was present in 6 cases (75%, 6/8). Normal liver parenchymal enhancement surrounding the main hepatic vein forming a clover-like sign was observed in 4 cases (25%, 4/16). The extent of patchy liver enhancement was statistically associated with clinical severity classification (kappa = 0.565). Ascites, patchy liver enhancement, and the main hepatic veins narrowing were the most frequent signs of herbal medicine induced HSOS. The grade of abnormal patchy liver enhancement was associated with the clinical severity.

Compound Wiretap Channels

Directory of Open Access Journals (Sweden)

Kramer Gerhard

2009-01-01

Full Text Available Abstract This paper considers the compound wiretap channel, which generalizes Wyner's wiretap model to allow the channels to the (legitimate receiver and to the eavesdropper to take a number of possible states. No matter which states occur, the transmitter guarantees that the receiver decodes its message and that the eavesdropper is kept in full ignorance about the message. The compound wiretap channel can also be viewed as a multicast channel with multiple eavesdroppers, in which the transmitter sends information to all receivers and keeps the information secret from all eavesdroppers. For the discrete memoryless channel, lower and upper bounds on the secrecy capacity are derived. The secrecy capacity is established for the degraded channel and the semideterministic channel with one receiver. The parallel Gaussian channel is further studied. The secrecy capacity and the secrecy degree of freedom ( are derived for the degraded case with one receiver. Schemes to achieve the for the case with two receivers and two eavesdroppers are constructed to demonstrate the necessity of a prefix channel in encoder design. Finally, the multi-antenna (i.e., MIMO compound wiretap channel is studied. The secrecy capacity is established for the degraded case and an achievable is given for the general case.

ATP Release Channels

Directory of Open Access Journals (Sweden)

Akiyuki Taruno

2018-03-01

Full Text Available Adenosine triphosphate (ATP has been well established as an important extracellular ligand of autocrine signaling, intercellular communication, and neurotransmission with numerous physiological and pathophysiological roles. In addition to the classical exocytosis, non-vesicular mechanisms of cellular ATP release have been demonstrated in many cell types. Although large and negatively charged ATP molecules cannot diffuse across the lipid bilayer of the plasma membrane, conductive ATP release from the cytosol into the extracellular space is possible through ATP-permeable channels. Such channels must possess two minimum qualifications for ATP permeation: anion permeability and a large ion-conducting pore. Currently, five groups of channels are acknowledged as ATP-release channels: connexin hemichannels, pannexin 1, calcium homeostasis modulator 1 (CALHM1, volume-regulated anion channels (VRACs, also known as volume-sensitive outwardly rectifying (VSOR anion channels, and maxi-anion channels (MACs. Recently, major breakthroughs have been made in the field by molecular identification of CALHM1 as the action potential-dependent ATP-release channel in taste bud cells, LRRC8s as components of VRACs, and SLCO2A1 as a core subunit of MACs. Here, the function and physiological roles of these five groups of ATP-release channels are summarized, along with a discussion on the future implications of understanding these channels.

Severe Hepatic Sinusoidal Obstruction Syndrome in a Child Receiving Vincristine, Actinomycin-D, and Cyclophosphamide for Rhabdomyosarcoma: Successful Treatment with Defibrotide.

Science.gov (United States)

Choi, Aery; Kang, Young Kyung; Lim, Sewon; Kim, Dong Ho; Lim, Jung Sub; Lee, Jun Ah

2016-10-01

Hepatic sinusoidal obstruction syndrome (SOS) is a life-threatening syndrome that generally occurs as a complication after hematopoietic stem cell transplantation or, less commonly, after conventional chemotherapy. Regarding SOS in rhabdomyosarcoma patients who received conventional chemotherapy, the doses of chemotherapeutic agents are associated with the development of SOS. Several cases of SOS in rhabdomyosarcoma patients after receiving chemotherapy with escalated doses of cyclophosphamide have been reported. Here, we report on a 9-year-old female with rhabdomyosarcoma who developed severe SOS after receiving chemotherapy consisting of vincristine, actinomycin-D, and a moderate dose of cyclophosphamide. She was treated successfully with defibrotide without sequelae to the liver.

Evaluation of sub grid scale and local wall models in Large-eddy simulations of separated flow

OpenAIRE

Sam Ali Al; Szasz Robert; Revstedt Johan

2015-01-01

The performance of the Sub Grid Scale models is studied by simulating a separated flow over a wavy channel. The first and second order statistical moments of the resolved velocities obtained by using Large-Eddy simulations at different mesh resolutions are compared with Direct Numerical Simulations data. The effectiveness of modeling the wall stresses by using local log-law is then tested on a relatively coarse grid. The results exhibit a good agreement between highly-resolved Large Eddy Simu...

Spark Channels

Energy Technology Data Exchange (ETDEWEB)

Haydon, S. C. [Department of Physics, University of New England, Armidale, NSW (Australia)

1968-04-15

A brief summary is given of the principal methods used for initiating spark channels and the various highly time-resolved techniques developed recently for studies with nanosecond resolution. The importance of the percentage overvoltage in determining the early history and subsequent development of the various phases of the growth of the spark channel is discussed. An account is then given of the recent photographic, oscillographic and spectroscopic investigations of spark channels initiated by co-axial cable discharges of spark gaps at low [{approx} 1%] overvoltages. The phenomena observed in the development of the immediate post-breakdown phase, the diffuse glow structure, the growth of the luminous filament and the final formation of the spark channel in hydrogen are described. A brief account is also given of the salient features emerging from corresponding studies of highly overvolted spark gaps in which the spark channel develops from single avalanche conditions. The essential differences between the two types of channel formation are summarized and possible explanations of the general features are indicated. (author)

Joint source/channel coding of scalable video over noisy channels

Energy Technology Data Exchange (ETDEWEB)

Cheung, G.; Zakhor, A. [Department of Electrical Engineering and Computer Sciences University of California Berkeley, California94720 (United States)

1997-01-01

We propose an optimal bit allocation strategy for a joint source/channel video codec over noisy channel when the channel state is assumed to be known. Our approach is to partition source and channel coding bits in such a way that the expected distortion is minimized. The particular source coding algorithm we use is rate scalable and is based on 3D subband coding with multi-rate quantization. We show that using this strategy, transmission of video over very noisy channels still renders acceptable visual quality, and outperforms schemes that use equal error protection only. The flexibility of the algorithm also permits the bit allocation to be selected optimally when the channel state is in the form of a probability distribution instead of a deterministic state. {copyright} {ital 1997 American Institute of Physics.}

Compound Wiretap Channels

Directory of Open Access Journals (Sweden)

Shlomo Shamai (Shitz

2009-01-01

Full Text Available This paper considers the compound wiretap channel, which generalizes Wyner's wiretap model to allow the channels to the (legitimate receiver and to the eavesdropper to take a number of possible states. No matter which states occur, the transmitter guarantees that the receiver decodes its message and that the eavesdropper is kept in full ignorance about the message. The compound wiretap channel can also be viewed as a multicast channel with multiple eavesdroppers, in which the transmitter sends information to all receivers and keeps the information secret from all eavesdroppers. For the discrete memoryless channel, lower and upper bounds on the secrecy capacity are derived. The secrecy capacity is established for the degraded channel and the semideterministic channel with one receiver. The parallel Gaussian channel is further studied. The secrecy capacity and the secrecy degree of freedom (s.d.o.f. are derived for the degraded case with one receiver. Schemes to achieve the s.d.o.f. for the case with two receivers and two eavesdroppers are constructed to demonstrate the necessity of a prefix channel in encoder design. Finally, the multi-antenna (i.e., MIMO compound wiretap channel is studied. The secrecy capacity is established for the degraded case and an achievable s.d.o.f. is given for the general case.

Effects of frequency and duration on psychometric functions for detection of increments and decrements in sinusoids in noise.

Science.gov (United States)

Moore, B C; Peters, R W; Glasberg, B R

1999-12-01

Psychometric functions for detecting increments or decrements in level of sinusoidal pedestals were measured for increment and decrement durations of 5, 10, 20, 50, 100, and 200 ms and for frequencies of 250, 1000, and 4000 Hz. The sinusoids were presented in background noise intended to mask spectral splatter. A three-interval, three-alternative procedure was used. The results indicated that, for increments, the detectability index d' was approximately proportional to delta I/I. For decrements, d' was approximately proportional to delta L. The slopes of the psychometric functions increased (indicating better performance) with increasing frequency for both increments and decrements. For increments, the slopes increased with increasing increment duration up to 200 ms at 250 and 1000 Hz, but at 4000 Hz they increased only up to 50 ms. For decrements, the slopes increased for durations up to 50 ms, and then remained roughly constant, for all frequencies. For a center frequency of 250 Hz, the slopes of the psychometric functions for increment detection increased with duration more rapidly than predicted by a "multiple-looks" hypothesis, i.e., more rapidly than the square root of duration, for durations up to 50 ms. For center frequencies of 1000 and 4000 Hz, the slopes increased less rapidly than predicted by a multiple-looks hypothesis, for durations greater than about 20 ms. The slopes of the psychometric functions for decrement detection increased with decrement duration at a rate slightly greater than the square root of duration, for durations up to 50 ms, at all three frequencies. For greater durations, the increase in slope was less than proportional to the square root of duration. The results were analyzed using a model incorporating a simulated auditory filter, a compressive nonlinearity, a sliding temporal integrator, and a decision device based on a template mechanism. The model took into account the effects of both the external noise and an assumed internal

A feedback control system for vibration of magnetostrictive plate subjected to follower force using sinusoidal shear

Directory of Open Access Journals (Sweden)

A. Ghorbanpour Arani

2016-03-01

Full Text Available In this research, the vibrational behavior of magnetostrictive plate (MsP as a smart component is studied. The plate is subjected to an external follower force and a magnetic field in which the vibration response of MsP has been investigated for both loading combinations. The velocity feedback gain parameter is evaluated to study the effect of magnetic field which is generated by the coil. Sinusoidal shear deformation theory is utilized due to its accuracy of polynomial function with respect to other plate theories. Equations of motion are derived using Hamilton’s principle and solved by differential quadrature method (DQM considering general boundary conditions. The effects of aspect ratio, thickness ratio, follower force and velocity feedback gain are investigated on the frequency response of MsP. Results indicate that magneto-mechanical coupling in MsM helps to control vibrational behaviors of systems such as electro-hydraulic actuator, wireless linear Motors and sensors.

Hepatic Sinusoidal Obstruction Syndrome During Chemotherapy for Childhood Medulloblastoma: Report of a Case and Review of the Literature

Science.gov (United States)

Buckland, Amy; Phillips, Marianne B.; Cole, Catherine H.; Gottardo, Nicholas G.

2014-01-01

Hepatic sinusoidal obstruction syndrome (HSOS), also known as veno-occlusive disease, is a well-recognized toxic complication after autologous and allogeneic hematopoietic stem cell transplant, during treatment of Wilms tumor and rhabdomyosarcoma associated with actinomycin-D, and during acute lymphoblastic leukemia therapy due to oral 6-thioguanine. However, its occurrence in the context of chemotherapy regimens for other childhood malignancies is rare. We report a 5-year-old girl with high-risk anaplastic medulloblastoma, who developed severe HSOS during her second cycle of maintenance chemotherapy, consisting of vincristine, cisplatin, and cyclophosphamide. She was treated with defibrotide with complete resolution of the HSOS. These findings and a review of the literature, highlight the occurrence of HSOS in children outside the established settings of hematopoietic stem cell transplantation, Wilms tumor, rhabdomyosarcoma, and acute lymphoblastic leukemia. PMID:24276042

Safety and effects of prophylactic defibrotide for sinusoidal obstruction syndrome in hematopoietic stem cell transplantation.

Science.gov (United States)

Park, Meerim; Park, Hyeon Jin; Eom, Hyeon-Seok; Kwon, Young Joo; Park, Jeong A; Lim, Yeon Jung; Yoon, Jong Hyung; Kong, Sun-Young; Ghim, Thad T; Lee, Hye Won; Yun, Tak; Park, Byung-Kiu

2013-01-28

Sinusoidal obstruction syndrome (SOS) is a serious complication of hematopoietic stem cell transplantation (HSCT), with a mortality rate of up to 90%. We report our experience on the use of defibrotide for SOS prophylaxis in HSCT. We retrospectively reviewed data of 49 patients who received defibrotide as SOS prophylaxis during the course of HSCT at the National Cancer Center, Goyang, Korea, between August 2005 and July 2008. Thirty-four patients (69.4%) were classified as a high-risk group for developing SOS. Defibrotide was well-tolerated, without any grade 3 or 4 toxicity. The median value of maximum total bilirubin within 100 days after HSCT was within the normal range. SOS was diagnosed in only 1 patient, who underwent autologous HSCT due to relapsed medulloblastoma. There was no day 100 treatment-related mortality in our study. Defibrotide appears to be a safe prophylaxis for SOS. This study suggests that it could be effective to use prophylactic defibrotide in advance to improve HSCT outcomes in patients at risk of SOS.

Quantum Channels With Memory

International Nuclear Information System (INIS)

Rybar, T.

2012-01-01

Quantum memory channels represent a very general, yet simple and comprehensible model for causal processes. As such they have attracted considerable research interest, mostly aimed on their transfer capabilities and structure properties. Most notably it was shown that memory channels can be implemented via physically naturally motivated collision models. We also define the concept of repeatable channels and show that only unital channels can be implemented repeat ably with pure memory channels. In the special case of qubit channels we also show that every unital qubit channel has a repeatable implementation. We also briefly explore the possibilities of stroboscopical simulation of channels and show that all random unitary channels can be stroboscopically simulated. Particularly in qubit case, all indivisible qubit channels are also random unitary, hence for qubit all indivisible channels can be stroboscopically simulated. Memory channels also naturally capture the framework of correlated experiments. We develop methods to gather and interpret data obtained in such setting and in detail examine the two qubit case. We also show that for control unitary interactions the measured data will never contradict a simple unitary evolution. Thus no memory effects can be spotted then. (author)

Current steering and current focusing in cochlear implants: comparison of monopolar, tripolar, and virtual channel electrode configurations.

Science.gov (United States)

Berenstein, Carlo K; Mens, Lucas H M; Mulder, Jef J S; Vanpoucke, Filiep J

2008-04-01

To compare the effects of Monopole (Mono), Tripole (Tri), and "Virtual channel" (Vchan) electrode configurations on spectral resolution and speech perception in a crossover design. Nine experienced adults who received an Advanced Bionics CII/90K cochlear implant participated in a crossover design using three experimental strategies for 2 wk each. Three strategies were compared: (1) Mono; (2) Tri with current partly returning to adjacent electrodes and partly (25 or 75%) to the extracochlear reference; and (3) a monopolar "Vchan" strategy creating seven intermediate channels between two contacts. Each strategy was a variant of the standard "HiRes" processing strategy using 14 channels and 1105 pulses/sec/ channel, and a pulse duration of 32 microsec/phase. Spectral resolution was measured using broadband noise with a sinusoidally rippled spectral envelope with peaks evenly spaced on a logarithmic frequency scale. Speech perception was measured for monosyllables in quiet and in steady-state and fluctuating noises. Subjective comments on music experience and preferences in everyday use were assessed through questionnaires. Thresholds and most comfortable levels with Mono and Vchan were both significantly lower than levels with Tri. Spectral resolution was significantly higher with Tri than with Mono; spectral resolution with Vchan did not differ significantly from the other configurations. Moderate but significant correlations between word recognition and spectral resolution were found in speech in quiet and fluctuating noise. For speech in quiet, word recognition was best with Mono and worst with Vchan; Tri did not significantly differ from the other configurations. Pooled across the noise conditions, word recognition was best with Tri and worst with Vchan (Mono did not significantly differ from the other configurations). These differences were small and insufficient to result in a clear increase in performance across subjects if the result from the best

Mimicking multi-channel scattering with single-channel approaches

OpenAIRE

Grishkevich, Sergey; Schneider, Philipp-Immanuel; Vanne, Yulian V.; Saenz, Alejandro

2009-01-01

The collision of two atoms is an intrinsic multi-channel (MC) problem as becomes especially obvious in the presence of Feshbach resonances. Due to its complexity, however, single-channel (SC) approximations, which reproduce the long-range behavior of the open channel, are often applied in calculations. In this work the complete MC problem is solved numerically for the magnetic Feshbach resonances (MFRs) in collisions between generic ultracold 6Li and 87Rb atoms in the ground state and in the ...

Fine Channel Networks

Science.gov (United States)

1997-01-01

A color image of fine channel networks on Mars; north toward top. The scene shows heavily cratered highlands dissected by dendritic open channel networks that dissect steep slopes of impact crater walls. This image is a composite of Viking high-resolution images in black and white and low-resolution images in color. The image extends from latitude 9 degrees S. to 5 degrees S. and from longitude 312 degrees to 320 degrees; Mercator projection. The dendritic pattern of the fine channels and their location on steep slopes leads to the interpretation that these are runoff channels. The restriction of these types of channels to ancient highland rocks suggests that these channels are old and date from a time on Mars when conditions existed for precipitation to actively erode rocks. After the channels reach a low plain, they appear to end. Termination may have resulted from burial by younger deposits or perhaps the flows percolated into the surface materials and continued underground.

Effect of fin pitch and number of tube rows on the air side performance of herringbone wavy fin and tube heat exchangers

International Nuclear Information System (INIS)

Wongwises, Somchai; Chokeman, Yutasak

2005-01-01

An experimental study is conducted to investigate the effects of a fin pitch and number of tube rows on the air side performance of fin and tube heat exchangers having herringbone wavy fin configuration at various fin thicknesses. A total of 10 samples of fin and tube heat exchanger with a tube outside diameter of 9.53mm, transverse tube pitch of 25.4mm and longitudinal tube pitch of 19.05mm, having various fin pitches, number of tube rows and fin thicknesses, are tested in a well insulated open wind tunnel. The heat exchangers are made from aluminium plate finned, copper tube. Ambient air is used as a working fluid in the air side while hot water is used for the tube side. The results are presented as the variation of the Colburn factor and the friction factor with the Reynolds number based on the fin collar outside diameter (Re D c ). The experimental results reveal that the fin pitch has an insignificant effect on the heat transfer characteristic. The friction factor increases with increasing fin pitch when Re D c >2500, approximately. The Colburn factor and the friction factor decrease with increasing number of tube rows when Re D c <4000, approximately. These results remain the same when the fin thickness is changed

Volume Regulated Channels

DEFF Research Database (Denmark)

Klausen, Thomas Kjær

of volume perturbations evolution have developed system of channels and transporters to tightly control volume homeostasis. In the past decades evidence has been mounting, that the importance of these volume regulated channels and transporters are not restricted to the defense of cellular volume...... but are also essential for a number of physiological processes such as proliferation, controlled cell death, migration and endocrinology. The thesis have been focusing on two Channels, namely the swelling activated Cl- channel (ICl, swell) and the transient receptor potential Vanilloid (TRPV4) channel. I: Cl......- serves a multitude of functions in the mammalian cell, regulating the membrane potential (Em), cell volume, protein activity and the driving force for facilitated transporters giving Cl- and Cl- channels a major potential of regulating cellular function. These functions include control of the cell cycle...

Evaluation and statistical judgement of neural responses to sinusoidal stimulation in cases with superimposed drift and noise.

Science.gov (United States)

Jastreboff, P W

1979-06-01

Time histograms of neural responses evoked by sinuosidal stimulation often contain a slow drifting and an irregular noise which disturb Fourier analysis of these responses. Section 2 of this paper evaluates the extent to which a linear drift influences the Fourier analysis, and develops a combined Fourier and linear regression analysis for detecting and correcting for such a linear drift. Usefulness of this correcting method is demonstrated for the time histograms of actual eye movements and Purkinje cell discharges evoked by sinusoidal rotation of rabbits in the horizontal plane. In Sect. 3, the analysis of variance is adopted for estimating the probability of the random occurrence of the response curve extracted by Fourier analysis from noise. This method proved to be useful for avoiding false judgements as to whether the response curve was meaningful, particularly when the response was small relative to the contaminating noise.

Hepatic sinusoidal obstruction syndrome during maintenance therapy of childhood acute lymphoblastic leukemia is associated with continuous asparaginase therapy and mercaptopurine metabolites

DEFF Research Database (Denmark)

Toksvang, Linea Natalie; De Pietri, Silvia; Nielsen, Stine N.

2017-01-01

BACKGROUND: Hepatic sinusoidal obstruction syndrome (SOS) during treatment of childhood acute lymphoblastic leukemia (ALL) has mainly been associated with 6-thioguanine. The occurrence of several SOS cases after the introduction of extended pegylated asparaginase (PEG-asparaginase) therapy...... in the Nordic Society of Paediatric Haematology and Oncology (NOPHO) ALL2008 protocol led us to hypothesize that PEG-asparaginase, combined with other drugs, may trigger SOS during 6-thioguanine-free maintenance therapy. PROCEDURE: In children with ALL treated in Denmark according to the NOPHO ALL2008 protocol...... children receiving PEG-asparaginase biweekly, 29 developed SOS (≥2 criteria: hyperbilirubinemia, hepatomegaly, ascites, weight gain ≥2.5%, unexplained thrombocytopenia

Gemtuzumab ozogamicin-induced sinusoidal obstructive syndrome treated with defibrotide: a case report.

Science.gov (United States)

Lannoy, D; Decaudin, B; Grozieux de Laguérenne, A; Barrier, F; Pignon, J M; Wetterwald, M; Odou, P

2006-08-01

New treatments for relapse of acute myeloid leukaemia (AML), include gemtuzumab ozogamicin (GO), an anti-CD33 monoclonal antibody. We describe a second case of GO-induced sinusoidal obstructive syndrome (SOS) effectively treated with defibrotide (DF). No stem-cell transplantation was involved. On day 23 after the first GO dose, a patient presented with ascites, weight gain, liver enlargement and pain in the right upper quadrant. Sudden hepatic cytolysis (transaminases at six times the normal range: grade 3) and cholestasis [alkaline phosphatase ALP and gamma-glutamyltransferase (GGT) respectively at four and eight times the normal range: grade 2] were observed but there was no evidence of increase serum bilirubin. Treatment with DF (Prociclide), Crinos; 10 mg/kg/day, or 200 mg, q.i.d.) improved the hepatic abnormality within a few days (serum transaminases decreased from 312 to 103 IU/L for aspartate aminotransferase (AST) and from 141 to 80 IU/L for alanine aminotransferase (ALT) within 3 days ALP increased from 253 to 383 IU/L and gamma-GT from 238 to 417 IU/L 4 days after administration of DF. The clinical and biological features of our case suggest a direct involvement of GO in causing SOS, even when used as monotherapy, without allogenic stem-cell transplantation. Low dose DF (10 mg/kg/day) given early during the development of SOS associated with GO was effective. Unfortunately, in our case the patient eventually died of multi-organ failure probably because of failure of GO.

Unsteady flow damping force prediction of MR dampers subjected to sinusoidal loading

Science.gov (United States)

Yu, M.; Wang, S. Q.; Fu, J.; Peng, Y. X.

2013-02-01

So far quasi-steady models are usually used to design magnetorheological (MR) dampers, but these models are not sufficient to describe the MR damper behavior under unsteady dynamic loading, for fluid inertia is neglected in quasi-steady models, which will bring more error between computer simulation and experimental results. Under unsteady flow model, the fluid inertia terms will bring error calculated upto 10%, so it is necessary to be considered in the governing equation. In this paper, force-stroke behavior of MR damper with flow mode due to sinusoidal loading excitation is mainly investigated, to simplify the analysis, the one-dimensional axisymmetric annular duct geometry of MR dampers is approximated as a rectangular duct. The rectangular duct can be divided into 3 regions for the velocity profile of the incompressible MR fluid flow, in each region, a partial differential equation is composed of by Navier-Stokes equations, boundary conditions and initial conditions to determine the velocity solution. In addition, in this work, not only Bingham plastic model but the Herschel—Bulkley model is adopted to analyze the MR damper performance. The damping force resulting from the pressure drop of unsteady MR dampers can be obtained and used to design or size MR dampers. Compared with the quasi-steady flow damping force, the damping force of unsteady MR dampers is more close to practice, particularly for the high-speed unsteady movement of MR dampers.

Unsteady flow damping force prediction of MR dampers subjected to sinusoidal loading

International Nuclear Information System (INIS)

Yu, M; Fu, J; Wang, S Q; Peng, Y X

2013-01-01

So far quasi-steady models are usually used to design magnetorheological (MR) dampers, but these models are not sufficient to describe the MR damper behavior under unsteady dynamic loading, for fluid inertia is neglected in quasi-steady models, which will bring more error between computer simulation and experimental results. Under unsteady flow model, the fluid inertia terms will bring error calculated upto 10%, so it is necessary to be considered in the governing equation. In this paper, force-stroke behavior of MR damper with flow mode due to sinusoidal loading excitation is mainly investigated, to simplify the analysis, the one-dimensional axisymmetric annular duct geometry of MR dampers is approximated as a rectangular duct. The rectangular duct can be divided into 3 regions for the velocity profile of the incompressible MR fluid flow, in each region, a partial differential equation is composed of by Navier-Stokes equations, boundary conditions and initial conditions to determine the velocity solution. In addition, in this work, not only Bingham plastic model but the Herschel—Bulkley model is adopted to analyze the MR damper performance. The damping force resulting from the pressure drop of unsteady MR dampers can be obtained and used to design or size MR dampers. Compared with the quasi-steady flow damping force, the damping force of unsteady MR dampers is more close to practice, particularly for the high-speed unsteady movement of MR dampers.

Dynamic analysis of double-row self-aligning ball bearings due to applied loads, internal clearance, surface waviness and number of balls

Science.gov (United States)

Zhuo, Yaobin; Zhou, Xiaojun; Yang, Chenlong

2014-11-01

In this paper, a three degrees of freedom (dof) model was established for a double-row self-aligning ball bearing (SABB) system, and was applied to study the dynamic behavior of the system during starting process and constant speed rotating process. A mathematical model was developed concerning stiffness and damping characteristics of the bearing, as well as three-dimensional applied load, rotor centrifugal force, etc. Balls and races were all considered as nonlinear springs, and the contact force between ball and race was calculated based on classic Hertzian elastic contact deformation theory and deformation compatibility theory. The changes of each ball's contact force and loaded angle of each row were taken into account. In order to solve the nonlinear dynamical equilibrium equations of the system, these equations were rewritten as differential equations and the fourth order Runge-Kutta method was used to solve the equations iteratively. In order to verify accuracy of the dynamical model and correctness of the numerical solution method, a kind of SABB-BRF30 was chosen for case studies. The effects of several important governing parameters, such as radial and axial applied loads, normal internal, inner and outer races waviness, and number of balls were investigated. These parametric studies led to a complete characterization of the shaft-bearing system vibration transmission. The research provided a theoretical reference for new type bearing design, shaft-bearing system kinetic analysis, optimal design, etc.

Amorphous Zinc Oxide Integrated Wavy Channel Thin Film Transistor Based High Performance Digital Circuits

KAUST Repository

Hanna, Amir; Hussain, Aftab M.; Omran, Hesham; Alshareef, Sarah; Salama, Khaled N.; Hussain, Muhammad Mustafa

2015-01-01

High performance thin film transistor (TFT) can be a great driving force for display, sensor/actuator, integrated electronics, and distributed computation for Internet of Everything applications. While semiconducting oxides like zinc oxide (Zn

A channel profile analyser

International Nuclear Information System (INIS)

Gobbur, S.G.

1983-01-01

It is well understood that due to the wide band noise present in a nuclear analog-to-digital converter, events at the boundaries of adjacent channels are shared. It is a difficult and laborious process to exactly find out the shape of the channels at the boundaries. A simple scheme has been developed for the direct display of channel shape of any type of ADC on a cathode ray oscilliscope display. This has been accomplished by sequentially incrementing the reference voltage of a precision pulse generator by a fraction of a channel and storing ADC data in alternative memory locations of a multichannel pulse height analyser. Alternative channels are needed due to the sharing at the boundaries of channels. In the flat region of the profile alternate memory locations are channels with zero counts and channels with the full scale counts. At the boundaries all memory locations will have counts. The shape of this is a direct display of the channel boundaries. (orig.)

RF model of the distribution system as a communication channel, phase 2. Volume 3: Appendices

Science.gov (United States)

Rustay, R. C.; Gajjar, J. T.; Rankin, R. W.; Wentz, R. C.; Wooding, R.

1982-01-01

Program documentation concerning the design, implementation, and verification of a computerized model for predicting the steady-state sinusoidal response of radial configured distribution feeders is presented in these appendices.

Ion channels in plants.

Science.gov (United States)

Hedrich, Rainer

2012-10-01

Since the first recordings of single potassium channel activities in the plasma membrane of guard cells more than 25 years ago, patch-clamp studies discovered a variety of ion channels in all cell types and plant species under inspection. Their properties differed in a cell type- and cell membrane-dependent manner. Guard cells, for which the existence of plant potassium channels was initially documented, advanced to a versatile model system for studying plant ion channel structure, function, and physiology. Interestingly, one of the first identified potassium-channel genes encoding the Shaker-type channel KAT1 was shown to be highly expressed in guard cells. KAT1-type channels from Arabidopsis thaliana and its homologs from other species were found to encode the K(+)-selective inward rectifiers that had already been recorded in early patch-clamp studies with guard cells. Within the genome era, additional Arabidopsis Shaker-type channels appeared. All nine members of the Arabidopsis Shaker family are localized at the plasma membrane, where they either operate as inward rectifiers, outward rectifiers, weak voltage-dependent channels, or electrically silent, but modulatory subunits. The vacuole membrane, in contrast, harbors a set of two-pore K(+) channels. Just very recently, two plant anion channel families of the SLAC/SLAH and ALMT/QUAC type were identified. SLAC1/SLAH3 and QUAC1 are expressed in guard cells and mediate Slow- and Rapid-type anion currents, respectively, that are involved in volume and turgor regulation. Anion channels in guard cells and other plant cells are key targets within often complex signaling networks. Here, the present knowledge is reviewed for the plant ion channel biology. Special emphasis is drawn to the molecular mechanisms of channel regulation, in the context of model systems and in the light of evolution.

A metabonomic evaluation of the monocrotaline-induced sinusoidal obstruction syndrome (SOS) in rats

International Nuclear Information System (INIS)

Conotte, R.; Colet, J.-M.

2014-01-01

The main curative treatment of colorectal cancer remains the surgery. However, when metastases are suspected, surgery is followed by a preventive chemotherapy using oxaliplatin which, unfortunately, may cause liver sinusoidal obstruction syndrome (SOS). Such hepatic damage is barely detected during or after chemotherapy due to a lack of effective diagnostic procedures, but liver biopsy. The primary objective of the present study was to identify potential early diagnosis biomarkers of SOS using a metabonomic approach. SOS was induced in rats by monocrotaline, a prototypical toxic substance. 1 H NMR spectroscopy analysis of urine samples collected from rats treated with monocrotaline showed significant metabolic changes as compared to controls. During a first phase, cellular protective mechanisms such as an increased synthesis of GSH (reduced taurine) and the recruitment of cell osmolytes in the liver (betaine) were seen. In the second phase, the disturbance of the urea cycle (increased ornithine and urea reduction) leading to the depletion of NO, the alteration in the GSH synthesis (increased creatine and GSH precursors (glutamate, dimethylglycine and sarcosine)), and the liver necrosis (decrease taurine and increase creatine) all indicate the development of SOS. - Highlights: • Urine metabonomic profiles of SOS have been identified. • Urine osmoprotectants and anti-oxidants indicated an initial liver protection. • Liver necrosis was demonstrated by increased urine levels of taurine and creatine. • NO depletion was suggested by changes in ornithine and urea

The Role of Thromboelastography in Pediatric Patients with Sinusoidal Obstructive Syndrome Receiving Defibrotide.

Science.gov (United States)

Gendreau, Joanna L; Knoll, Christine; Adams, Roberta H; Su, Leon L

2017-04-01

Sinusoidal obstructive syndrome (SOS) is a potentially fatal form of hepatic injury after hematopoietic stem cell transplantation. Patients can develop liver dysfunction, portal hypertension, ascites, coagulopathies, and multisystem organ failure. The mortality rate of severe SOS has been reported as high as 98% by day 100 after transplantation. Defibrotide, which is now approved for the treatment of SOS, has significantly decreased mortality. Defibrotide is a polynucleotide with profibrinolytic, anti-ischemic, and anti-inflammatory activity. These properties can increase the risk of life-threatening bleeding in this patient population. Previous protocols have suggested maintaining international normalized ratio ≤ 1.5, platelets > 30 k/uL, and fibrinogen ≥ 150 mg/dL to minimize this risk of bleeding. However, this can be challenging in fluid-sensitive patients with SOS. Thromboelastography (TEG) is a functional assay that evaluates the balance of procoagulant and anticoagulant proteins. In this series, TEG was used to guide defibrotide therapy as well as blood product transfusions in SOS patients with abnormal coagulation studies. Each patient recovered from SOS and had no bleeding complications. A randomized clinical trial is the next step in supporting the use of TEG in SOS patients with abnormal coagulation studies receiving defibrotide therapy. Copyright © 2017 The American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

Channel and Timeslot Co-Scheduling with Minimal Channel Switching for Data Aggregation in MWSNs

Directory of Open Access Journals (Sweden)

Sanggil Yeoum

2017-05-01

Full Text Available Collision-free transmission and efficient data transfer between nodes can be achieved through a set of channels in multichannel wireless sensor networks (MWSNs. While using multiple channels, we have to carefully consider channel interference, channel and time slot (resources optimization, channel switching delay, and energy consumption. Since sensor nodes operate on low battery power, the energy consumed in channel switching becomes an important challenge. In this paper, we propose channel and time slot scheduling for minimal channel switching in MWSNs, while achieving efficient and collision-free transmission between nodes. The proposed scheme constructs a duty-cycled tree while reducing the amount of channel switching. As a next step, collision-free time slots are assigned to every node based on the minimal data collection delay. The experimental results demonstrate that the validity of our scheme reduces the amount of channel switching by 17.5%, reduces energy consumption for channel switching by 28%, and reduces the schedule length by 46%, as compared to the existing schemes.

Surface channeling

International Nuclear Information System (INIS)

Sizmann, R.; Varelas, C.

1976-01-01

There is experimental evidence that swift light ions incident at small angles towards single crystalline surfaces can lose an appreciable fraction of their kinetic energy during reflection. It is shown that these projectiles penetrate into the bulk surface region of the crystal. They can travel as channeled particles along long paths through the solid (surface channeling). The angular distribution and the depth history of the re-emerged projectiles are investigated by computer simulations. A considerable fraction of the penetrating projectiles re-emerges from the crystal with constant transverse energy if the angle of incidence is smaller than the critical angle for axial channeling. Analytical formulae are derived based on a diffusion model for surface channeling. A comparison with experimental data exhibits the relevance of the analytical solutions. (Auth.)

CFD analysis of the VHTR prismatic core with variation of geometry parameters

Energy Technology Data Exchange (ETDEWEB)

Lira, Carlos A.B.O.; Paiva, Pedro P.D.S., E-mail: cabol@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Energia Nuclear

2017-11-01

The Very High Temperature Reactor is a thermal, graphite moderated and helium cooled nuclear reactor. The purpose of this work is to study the behavior of the VHTR by means of parametric analysis, altering the energy generation profile in the fuel blocks and the influence of modifications in the geometry itself. The coolant flow through the coolant channels and by-pass channels were analyzed in a 1/12{sup th} section of a fuel block column. Geometry was used with by-pass channels of different dimensions, besides one that had only the cooling channels, without by-pass channel. It has been found that the existence of a by-pass flow induces an increase in the temperature gradient in the fuel block. Comparative studies were performed between the results obtained in simulations carried out with different profiles of thermal energy generation (uniform and sinusoidal) in the fuel channels. It was verified that when there is the same total thermal energy generation in the fuel block, the maximum temperature observed in each of the materials is smaller for the generation with sinusoidal profile. Computer simulations were performed using a geometry with a central channel with the same diameter as the others to verify the hypothesis that the existence of a temperature gradient in the fuel block, with the highest temperature at the center and the lowest temperature being at the periphery of this block, is due to the smaller dimension of the coolant channel located in the center of this block. The results obtained confirm the hypothesis. (author)

An information-guided channel-hopping scheme for block-fading channels with estimation errors

KAUST Repository

Yang, Yuli

2010-12-01

Information-guided channel-hopping technique employing multiple transmit antennas was previously proposed for supporting high data rate transmission over fading channels. This scheme achieves higher data rates than some mature schemes, such as the well-known cyclic transmit antenna selection and space-time block coding, by exploiting the independence character of multiple channels, which effectively results in having an additional information transmitting channel. Moreover, maximum likelihood decoding may be performed by simply decoupling the signals conveyed by the different mapping methods. In this paper, we investigate the achievable spectral efficiency of this scheme in the case of having channel estimation errors, with optimum pilot overhead for minimum meansquare error channel estimation, when transmitting over blockfading channels. Our numerical results further substantiate the robustness of the presented scheme, even with imperfect channel state information. ©2010 IEEE.

Corrigendum to "Sinusoidal potential cycling operation of a direct ethanol fuel cell to improving carbon dioxide yields" [J. Power Sources 268 (5 December 2014) 439-442

Science.gov (United States)

Majidi, Pasha; Pickup, Peter G.

2016-09-01

The authors regret that Equation (5) is incorrect and has resulted in errors in Fig. 4 and the efficiencies stated on p. 442. The corrected equation, figure and text are presented below. In addition, the title should be 'Sinusoidal potential cycling operation of a direct ethanol fuel cell to improve carbon dioxide yields', and the reversible cell potential quoted on p. 441 should be 1.14 V. The authors would like to apologise for any inconvenience caused.

Charged and Neutral Particles Channeling Phenomena Channeling 2008

Science.gov (United States)

Dabagov, Sultan B.; Palumbo, Luigi

2010-04-01

On the discovery of coherent Bremsstrahlung in a single crystal at the Frascati National Laboratories / C. Barbiellini, G. P. Murtas and S. B. Dabagov -- Advances in coherent Bremsstrahlung and LPM-effect studies (to the lOOth anniversary from the birth of L. D. Landau) / N. F. Shul'ga -- Spectra of radiation and created particles at intermediate energy in oriented crystal taking into account energy loss / V. N. Baier and V. M. Katkov -- The coherent Bremsstrahlung beam at MAX-lab facility / K. Fissum ... [et al.] -- Radiation from thin, structured targets (CERN NA63) / A. Dizdar -- Hard incoherent radiation in thick crystals / N. F. Shul'ga, V. V. Syshchenko and A. I. Tarnovsky -- Coherent Bremsstrahlung in periodically deformed crystals with a complex base / A. R. Mkrtchyan, A. A. Saharian and V. V. Parazian -- Induction of coherent x-ray Bremsstrahlung in crystals under the influence of acoustic waves / A. R. Mkrtchyan and V. V. Parazian -- Coherent processes in bent single crystals / V. A. Maisheev -- Experimental and theoretical investigation of complete transfer phenomenon for media with various heat exchange coefficients / A. R. Mkrtchyan, A. E. Movsisyan and V. R. Kocharyan -- Coherent pair production in crystals / A. R. Mkrtchyan, A. A. Saharian and V. V. Parazian -- Negative particle planar and axial channeling and channeling collimation / R. A. Carrigan, Jr. -- CERN crystal-based collimation in modern hadron colliders / W. Scandale -- Studies and application of bent crystals for beam steering at 70 GeV IHEP accelerator / A. G. Afonin ... [et al.] -- Crystal collimation studies at the Tevatron (T-980) / N. V. Mokhov ... [et al.] -- Fabrication of crystals for channeling of particles in accellerators / A. Mazzolari ... [et al.] -- New possibilities to facilitate collimation of both positively and negatively charged particle beams by crystals / V. Guidi, A. Mazzolari and V. V. Tikhomirov -- Increase of probability of particle capture into the channeling

Flame Structure and Chemiluminescence Emissions of Inverse Diffusion Flames under Sinusoidally Driven Plasma Discharges

Directory of Open Access Journals (Sweden)

Maria Grazia De Giorgi

2017-03-01

Full Text Available Reduction of nitric oxides (NOx in aircraft engines and in gas turbines by lean combustion is of great interest in the design of novel combustion systems. However, the stabilization of the flame under lean conditions is a main issue. In this context, the present work investigates the effects of sinusoidal dielectric barrier discharge (DBD on a lean inverse diffusive methane/air flame in a Bunsen-type burner under different actuation conditions. The flame appearance was investigated with fixed methane loading (mass flux, but with varying inner airflow rate. High-speed flame imaging was done by using an intensified (charge-coupled device CCD camera equipped with different optical filters in order to selectively record signals from the chemiluminescent species OH*, CH*, or CO2* to evaluate the flame behavior in presence of plasma actuation. The electrical power consumption was less than 33 W. It was evident that the plasma flame enhancement was significantly influenced by the plasma discharges, particularly at high inner airflow rates. The flame structure changes drastically when the dissipated plasma power increases. The flame area decreases due to the enhancement of mixing and chemical reactions that lead to a more anchored flame on the quartz exit with a reduction of the flame length.

Flagellum motion in 2-D: Work rate and efficiency of the non-sinusoidal approach

Science.gov (United States)

Viridi, Sparisoma; Nuraini, Nuning; Stephanie, Monica; Rifqi, Ainur; Christina, Dina; Thania, Elsa; Sihite, Erland

2018-03-01

Today microorganisms have been widely used to support human life. Some examples include foodstuffs (Spirulina.sp), to help with medical needs, for mining purposes and more. On the other hand, the development of technology is also very big influence on human life. The combination of technology and health science will be very useful if we can develop it. One is the cancer treatment by utilizing the movement of the flagella to be made a nanorobot used as a carrier of cancer drugs. Movement of flagella that resembles the shape of the arc and straight line can be searched formulation and then applied to the manufacture of nanorobot tail. Then the nanorobot will carry a cancer drug that leads directly to the cancer cells. So hopefully with this nanorobot, can minimize the death of healthy cells around cancer cells. From the results of research and analysis of the movement of flagella, it can be concluded that the smaller the mass of the flagella, the greater the efficiency will be or will be more efficient. So, the energy needed nanorobot will be smaller. Model with non-sinusoidal approach (Brokaw, 1965) is discussed in this work and formulation to get the energy efficiency is proposed and analyzed. Unfortunately, there is a negative value in the formulation.

Diagnostic performance of Contrast-enhanced CT in Pyrrolizidine Alkaloids-induced Hepatic Sinusoidal Obstructive Syndrome

Science.gov (United States)

Kan, Xuefeng; Ye, Jin; Rong, Xinxin; Lu, Zhiwen; Li, Xin; Wang, Yong; Yang, Ling; Xu, Keshu; Song, Yuhu; Hou, Xiaohua

2016-01-01

Hepatic sinusoidal obstruction syndrome (HSOS) can be caused by pyrrolizidine alkaloids(PAs)-containing herbals. Since PAs exposure is obscure and clinical presentation of HSOS is unspecific, it is challenge to establish the diagnosis of PAs-induced HSOS. Gynura segetum is one of the most wide-use herbals containing PAs. The aim of our study is to describe the features of contrast-enhanced computed tomography (CT) in gynura segetum-induced HSOS, and then determine diagnostic performance of radiological signs. We retrospectively analyzed medical records and CT images of HSOS patients (71 cases) and the controls (222 cases) enrolled from January 1, 2008, to Oct 31, 2015. The common findings of contrast CT in PAs-induced HSOS included: ascites (100%), hepatomegaly (78.87%), gallbladder wall thickening (86.96%), pleural effusion (70.42%), hepatic vein narrowing (87.32%), patchy liver enhancement (92.96%), and heterogeneous hypoattenuation (100%); of these signs, patchy enhancement and heterogeneous hypoattenuation were valuable features. Then, the result of diagnostic performance demonstrated that contrast CT possessed better performance in diagnosing PAs-induced HSOS compared with various parameters of Seattle criteria. In conclusion, the patients with PAs-induced HSOS display distinct radiologic features at CT-scan, which reveals that contrast-enhanced CT provides an effective noninvasive method for diagnosing PAs-induced HSOS. PMID:27897243

Potassium channels in brain mitochondria.

Science.gov (United States)

Bednarczyk, Piotr

2009-01-01

Potassium channels are the most widely distributed class of ion channels. These channels are transmembrane proteins known to play important roles in both normal and pathophysiological functions in all cell types. Various potassium channels are recognised as potential therapeutic targets in the treatment of Parkinson's disease, Alzheimer's disease, brain/spinal cord ischaemia and sepsis. In addition to their importance as therapeutic targets, certain potassium channels are known for their beneficial roles in anaesthesia, cardioprotection and neuroprotection. Some types of potassium channels present in the plasma membrane of various cells have been found in the inner mitochondrial membrane as well. Potassium channels have been proposed to regulate mitochondrial membrane potential, respiration, matrix volume and Ca(+) ion homeostasis. It has been proposed that mitochondrial potassium channels mediate ischaemic preconditioning in various tissues. However, the specificity of a pharmacological agents and the mechanisms underlying their effects on ischaemic preconditioning remain controversial. The following potassium channels from various tissues have been identified in the inner mitochondrial membrane: ATP-regulated (mitoK(ATP)) channel, large conductance Ca(2+)-regulated (mitoBK(Ca)) channel, intermediate conductance Ca(2+)-regulated (mitoIK(Ca)) channel, voltage-gated (mitoKv1.3 type) channel, and twin-pore domain (mitoTASK-3) channel. It has been shown that increased potassium flux into brain mitochondria induced by either the mitoK(ATP) channel or mitoBK(Ca) channel affects the beneficial effects on neuronal cell survival under pathological conditions. Recently, differential distribution of mitoBK(Ca) channels has been observed in neuronal mitochondria. These findings may suggest a neuroprotective role for the mitoBK(Ca) channel in specific brain structures. This minireview summarises current data on brain mitochondrial potassium channels and the efforts to identify

Channel allocation and rate adaptation for relayed transmission over correlated fading channels

KAUST Repository

Hwang, Kyusung

2009-09-01

We consider, in this paper, channel allocation and rate adaptation scheme for relayed transmission over correlated fading channels via cross-layer design. Specifically, jointly considering the data link layer buffer occupancy and channel quality at both the source and relay nodes, we develop an optimal channel allocation and rate adaptation policy for a dual-hop relayed transmission. As such the overall transmit power for the relayed system is minimized while a target packet dropping rate (PDR) due to buffer over flows is guaranteed. In order to find such an optimal policy, the channel allocation and rate adaptation transmission framework is formulated as a constraint Markov decision process (CMDP). The PDR performance of the optimal policy is compared with that of two conventional suboptimal schemes, namely the channel quality based and the buffer occupancy based channel allocation schemes. Numerical results show that for a given power budget, the optimal scheme requires significantly less power than the conventional schemes in order to maintain a target PDR. ©2009 IEEE.

Engraftment and reconstitution of hematopoiesis is dependent on VEGFR2 mediated regeneration of sinusoidal endothelial cells

Science.gov (United States)

Hooper, Andrea T.; Butler, Jason M.; Nolan, Daniel J; Kranz, Andrea; Iida, Kaoruko; Kobayashi, Mariko; Kopp, Hans-Georg; Shido, Koji; Petit, Isabelle; Yanger, Kilangsungla; James, Daylon; Witte, Larry; Zhu, Zhenping; Wu, Yan; Pytowski, Bronislaw; Rosenwaks, Zev; Mittal, Vivek; Sato, Thomas N.; Rafii, Shahin

2011-01-01

SUMMARY The phenotypic attributes and molecular determinants for the regeneration of bone marrow (BM) sinusoidal endothelial cells (SECs) and their contribution to hematopoiesis are unknown. We show that after myelosuppression VEGFR2 activation promotes reassembly of regressed SECs, reconstituting hematopoietic stem and progenitor cells (HSPCs). VEGFR2 and VEGFR3 expression are restricted to BM vasculature, demarcating a continuous network of VEGFR2+VEGFR3+Sca1− SECs and VEGFR2+VEGFR3−Sca1+ arterioles. While chemotherapy (5FU) and sublethal irradiation (650 rad) induce minor SEC regression, lethal irradiation (950 rad) induces severe regression of SECs requiring BM transplantation (BMT) for regeneration. Conditional deletion of VEGFR2 in adult mice blocks regeneration of SECs in sublethally irradiated animals, preventing hematopoietic reconstitution. Inhibition of VEGFR2 signaling in lethally irradiated wild type mice rescued with BMT severely impairs SEC reconstruction, preventing engraftment and reconstitution of HSPCs. Therefore, activation of VEGFR2 is critical for regeneration of VEGFR3+Sca1− SECs that are essential for engraftment and restoration of HSPCs and hematopoiesis. PMID:19265665

Bevacizumab exacerbates sinusoidal obstruction syndrome (SOS) in the animal model and increases MMP 9 production.

Science.gov (United States)

Jafari, Azin; Matthaei, Hanno; Wehner, Sven; Tonguc, Tolga; Kalff, Jörg C; Manekeller, Steffen

2018-04-24

Thanks to modern multimodal treatment the ouctome of patients with colorectal cancer has experienced significant improvements. As a downside, agent specific side effects have been observed such as sinusoidal obstruction syndrome (SOS) after oxaliplatin chemotherapy (OX). Bevazicumab targeting VEGF is nowadays comprehensively used in combination protocols with OX but its impact on hepatotoxicity is thus far elusive and focus of the present study. After MCT administration 67% of animals developed SOS. GOT serum concentration significantly increased in animals developing SOS ( p SOS. In contrast, animals receiving VEGF developed SOS merely in 40% while increasing the VEGF dose led to a further decrease in SOS development to 25%. MMP 9 concentration in animals developing SOS was significantly higher compared to controls ( p SOS paralleled by MMP 9 production. Therefore, OX-Bevacizumab combination therapies should be administered with caution, especially if liver parenchyma damage is apparent. Male Sprague-Dawley rats were gavaged Monocrotaline (MCT) to induce SOS. Recombinant VEGF or an Anti-VEGF antibody was administered to MCT-treated rats and the hepatotoxic effect monitored in defined time intervals. MMP 9 expression in the liver was measured by ELISA.

Sinusoidal Obstruction Syndrome during Treatment for Wilms' Tumor: A Life-threatening Complication.

Science.gov (United States)

Totadri, Sidharth; Trehan, Amita; Bansal, Deepak; Jain, Richa

2017-01-01

Survival rates exceed 90% in Wilms' tumor (WT). Actinomycin-D (ACT-D) which is indispensable in the management of WT is associated with the development of sinusoidal obstruction syndrome (SOS), a potentially fatal complication. The aim is to study the presentation, management, and outcome of SOS complicating ACT-D administration in WT. Retrospective file review conducted in a Pediatric Hematology-Oncology unit. Patients diagnosed and treated for WT from January 2012 to December 2015 were analyzed. SOS was diagnosed clinically, based on McDonalds criteria, requiring two of the following: jaundice, hepatomegaly and/or right upper quadrant pain, weight gain with or without ascites. Of 104 patients treated, SOS occurred in 5 (4.8%). Age: 6 months to 5 years, 3 were girls. Tumor involved left kidney in 3, right in 1 and a horseshoe kidney in 1. Histopathology was consistent with WT in 4 and clear cell sarcoma kidney in 1. One had pulmonary metastases. Three developed SOS preoperatively and two during adjuvant chemotherapy. None received radiotherapy. Clinical manifestations comprised of jaundice, hepatomegaly, ascites/weight gain, respiratory distress, hypotension, and encephalopathy. Laboratory findings included thrombocytopenia, elevated serum transaminases, and coagulopathy. Treatment included fluid restriction, broad spectrum antibiotics, and transfusional support. Two children received N-acetyl cysteine infusion. Defibrotide was administered to two patients. Four recovered and one succumbed to multi-organ failure. Two patients were safely re-challenged with 50% doses of ACT-D. SOS is a clinical diagnosis. Systematic supportive care can enable complete recovery. Under close monitoring, re-challenge of ACT-D can be performed in gradually escalating doses.

Laser-induced nonlinear crystalline waveguide on glass fiber format and diode-pumped second harmonic generation

Science.gov (United States)

Shi, Jindan; Feng, Xian

2018-03-01

We report a diode pumped self-frequency-doubled nonlinear crystalline waveguide on glass fiber. A ribbon fiber has been drawn on the glass composition of 50GeO2-25B2O3-25(La,Yb)2O3. Surface channel waveguides have been written on the surface of the ribbon fiber, using space-selective laser heating method with the assistance of a 244 nm CW UV laser. The Raman spectrum of the written area indicates that the waveguide is composed of structure-deformed nonlinear (La,Yb)BGeO5 crystal. The laser-induced surface wavy cracks have also been observed and the forming mechanism of the wavy cracks has been discussed. Efficient second harmonic generation has been observed from the laser-induced crystalline waveguide, using a 976 nm diode pump. 13 μW of 488 nm output has been observed from a 17 mm long waveguide with 26.0 mW of launched diode pump power, corresponding to a normalized conversion efficiency of 4.4%W-1.

An optimized method for mouse liver sinusoidal endothelial cell isolation

Energy Technology Data Exchange (ETDEWEB)

Meyer, Jeremy, E-mail: jeremy.meyer@hcuge.ch [Division of Digestive and Transplantation Surgery, University Hospitals of Geneva, Rue Gabrielle-Perret-Gentil 4, 1211 Genève 14 (Switzerland); Unit of Surgical Research, University of Geneva, Rue Michel-Servet 1, 1206 Genève (Switzerland); Lacotte, Stéphanie, E-mail: stephanie.lacotte@unige.ch [Unit of Surgical Research, University of Geneva, Rue Michel-Servet 1, 1206 Genève (Switzerland); Morel, Philippe, E-mail: philippe.morel@hcuge.ch [Division of Digestive and Transplantation Surgery, University Hospitals of Geneva, Rue Gabrielle-Perret-Gentil 4, 1211 Genève 14 (Switzerland); Unit of Surgical Research, University of Geneva, Rue Michel-Servet 1, 1206 Genève (Switzerland); Gonelle-Gispert, Carmen, E-mail: carmen.gonelle@unige.ch [Unit of Surgical Research, University of Geneva, Rue Michel-Servet 1, 1206 Genève (Switzerland); Bühler, Léo, E-mail: leo.buhler@hcuge.ch [Division of Digestive and Transplantation Surgery, University Hospitals of Geneva, Rue Gabrielle-Perret-Gentil 4, 1211 Genève 14 (Switzerland); Unit of Surgical Research, University of Geneva, Rue Michel-Servet 1, 1206 Genève (Switzerland)

2016-12-10

The objective of the present study was to develop an accurate and reproducible method for liver sinusoidal endothelial cell (LSEC) isolation in mice. Non-parenchymal cells were isolated using a modified two-step collagenase digestion combined with Optiprep density gradient centrifugation. LSEC were further purified using two prevalent methods, short-term selective adherence and CD146+ magnetic-activated cell sorting (MACS), and compared in terms of cell yield, viability and purity to our purification technique using CD11b cell depletion combined with long-term selective adherence. LSEC purification using our technique allowed to obtain 7.07±3.80 million LSEC per liver, while CD146+ MACS and short-term selective adherence yielded 2.94±1.28 and 0.99±0.66 million LSEC, respectively. Purity of the final cell preparation reached 95.10±2.58% when using our method. In contrast, CD146+ MACS and short-term selective adherence gave purities of 86.75±3.26% and 47.95±9.82%, respectively. Similarly, contamination by non-LSEC was the lowest when purification was performed using our technique, with a proportion of contaminating macrophages of only 1.87±0.77%. Further, isolated cells analysed by scanning electron microscopy presented typical LSEC fenestrations organized in sieve plates, demonstrating that the technique allowed to isolate bona fide LSEC. In conclusion, we described a reliable and reproducible technique for the isolation of high yields of pure LSEC in mice. This protocol provides an efficient method to prepare LSEC for studying their biological functions. - Highlights: • This protocol provides an efficient method to prepare primary mouse LSEC for studying their biological functions. • The liver cell dispersion step was improved by performing a retrograde cannulation of the liver. • The cell yield and the purity obtained were higher than comparative techniques in mice. • Contaminating macrophages were removed by introducing a CD11b- magnetic �

An optimized method for mouse liver sinusoidal endothelial cell isolation

International Nuclear Information System (INIS)

Meyer, Jeremy; Lacotte, Stéphanie; Morel, Philippe; Gonelle-Gispert, Carmen; Bühler, Léo

2016-01-01

The objective of the present study was to develop an accurate and reproducible method for liver sinusoidal endothelial cell (LSEC) isolation in mice. Non-parenchymal cells were isolated using a modified two-step collagenase digestion combined with Optiprep density gradient centrifugation. LSEC were further purified using two prevalent methods, short-term selective adherence and CD146+ magnetic-activated cell sorting (MACS), and compared in terms of cell yield, viability and purity to our purification technique using CD11b cell depletion combined with long-term selective adherence. LSEC purification using our technique allowed to obtain 7.07±3.80 million LSEC per liver, while CD146+ MACS and short-term selective adherence yielded 2.94±1.28 and 0.99±0.66 million LSEC, respectively. Purity of the final cell preparation reached 95.10±2.58% when using our method. In contrast, CD146+ MACS and short-term selective adherence gave purities of 86.75±3.26% and 47.95±9.82%, respectively. Similarly, contamination by non-LSEC was the lowest when purification was performed using our technique, with a proportion of contaminating macrophages of only 1.87±0.77%. Further, isolated cells analysed by scanning electron microscopy presented typical LSEC fenestrations organized in sieve plates, demonstrating that the technique allowed to isolate bona fide LSEC. In conclusion, we described a reliable and reproducible technique for the isolation of high yields of pure LSEC in mice. This protocol provides an efficient method to prepare LSEC for studying their biological functions. - Highlights: • This protocol provides an efficient method to prepare primary mouse LSEC for studying their biological functions. • The liver cell dispersion step was improved by performing a retrograde cannulation of the liver. • The cell yield and the purity obtained were higher than comparative techniques in mice. • Contaminating macrophages were removed by introducing a CD11b- magnetic �

On the secrecy capacity of the MISO wiretap channel under imperfect channel estimation

KAUST Repository

Rezki, Zouheir; Alomair, Basel; Alouini, Mohamed-Slim

2014-01-01

We consider a wiretap channel consisting of a source with multiple antennas, a legitimate receiver and an eavesdropper with a single antenna each. The channels between the source and the receivers undergo fast fading. We assume that the transmitter, in addition to the statistics of both channels, is only aware of a noisy version of the CSI to the legitimate receiver referred to as main channel. The legitimate receiver is aware of both its instantaneous channel gain and the transmitter's estimate of the main channel. On the other hand, the eavesdropper's receiver, in addition to its instantaneous channel realization, is aware of the actual main CSI and the transmitter's estimate as well. While the capacity of this channel is still open even with perfect CSI at the transmitter, we provide in this paper upper and lower bounds on the secrecy capacity. The upper bound is tighter than the one corresponding to perfect main CSI and the gap between the two upper bounds is characterized in function of the channel estimation error variance, at high-SNR. Furthermore, we show that our upper and lower bounds coincide in the case of no main CSI providing a trivial secrecy capacity.

Differential on-on keying: A robust non-coherent digital modulation scheme

KAUST Repository

Kaddoum, Georges

2015-05-01

A robust digital modulation scheme, called differential on-on keying (DOOK), is presented in this paper which outperforms the conventional on-off keying (OOK). In this scheme, a sinusoidal signal is transmitted during the first half of the bit duration while a replica or an inverted version of the sinusoidal signal is transmitted during the second half for logic one or logic zero, respectively. Non-coherent receiver correlates the two halves of the received signal over half bit duration to construct a decision variable. Bit error performance is analyzed over AWGN and Rayleigh fading channels and compared to the conventional OOK.

Differential on-on keying: A robust non-coherent digital modulation scheme

KAUST Repository

Kaddoum, Georges; Ahmed, Mohammed F. A.; Al-Naffouri, Tareq Y.

2015-01-01

A robust digital modulation scheme, called differential on-on keying (DOOK), is presented in this paper which outperforms the conventional on-off keying (OOK). In this scheme, a sinusoidal signal is transmitted during the first half of the bit duration while a replica or an inverted version of the sinusoidal signal is transmitted during the second half for logic one or logic zero, respectively. Non-coherent receiver correlates the two halves of the received signal over half bit duration to construct a decision variable. Bit error performance is analyzed over AWGN and Rayleigh fading channels and compared to the conventional OOK.

A linearization of quantum channels

Science.gov (United States)

Crowder, Tanner

2015-06-01

Because the quantum channels form a compact, convex set, we can express any quantum channel as a convex combination of extremal channels. We give a Euclidean representation for the channels whose inverses are also valid channels; these are a subset of the extreme points. They form a compact, connected Lie group, and we calculate its Lie algebra. Lastly, we calculate a maximal torus for the group and provide a constructive approach to decomposing any invertible channel into a product of elementary channels.

Channel Characteristics and Transmission Performance for Various Channel Configurations at 60 GHz

Directory of Open Access Journals (Sweden)

Yang Haibing

2007-01-01

Full Text Available Extensive measurements are conducted in room environments at 60 GHz to analyze the channel characteristics for various channel configurations. Channel parameters retrieved from measurements are presented and analyzed based on generic channel models. Particularly, a simple single-cluster model is applied for the parameter retrieval and performance evaluation. By this model, power delay profiles are simply described by a -factor, a root-mean-squared delay spread, and a shape parameter. The considered channels are configured with the combination of omnidirectional, fan-beam, and pencil-beam antennas at transmitter and receiver sides. Both line-of-sight (LOS and non-LOS (NLOS channels are considered. Further, to evaluate the transmission performance, we analyze the link budget in the considered environments, then design and simulate an OFDM system with a data rate of 2 Gbps to compare the bit-error-rate (BER performance by using the measured and modeled channels. Both coded and uncoded OFDM systems are simulated. It is observed that the BER performance agrees well for the measured and modeled channels. In addition, directive configurations can provide sufficient link margins and BER performance for high data rate communications. To increase the coverage and performance in the NLOS area, it is preferable to apply directive antennas.

Channel Characteristics and Transmission Performance for Various Channel Configurations at 60 GHz

Directory of Open Access Journals (Sweden)

Haibing Yang

2007-05-01

Full Text Available Extensive measurements are conducted in room environments at 60 GHz to analyze the channel characteristics for various channel configurations. Channel parameters retrieved from measurements are presented and analyzed based on generic channel models. Particularly, a simple single-cluster model is applied for the parameter retrieval and performance evaluation. By this model, power delay profiles are simply described by a K-factor, a root-mean-squared delay spread, and a shape parameter. The considered channels are configured with the combination of omnidirectional, fan-beam, and pencil-beam antennas at transmitter and receiver sides. Both line-of-sight (LOS and non-LOS (NLOS channels are considered. Further, to evaluate the transmission performance, we analyze the link budget in the considered environments, then design and simulate an OFDM system with a data rate of 2 Gbps to compare the bit-error-rate (BER performance by using the measured and modeled channels. Both coded and uncoded OFDM systems are simulated. It is observed that the BER performance agrees well for the measured and modeled channels. In addition, directive configurations can provide sufficient link margins and BER performance for high data rate communications. To increase the coverage and performance in the NLOS area, it is preferable to apply directive antennas.

Volume of the space of qubit-qubit channels and state transformations under random quantum channels

OpenAIRE

Lovas, Attila; Andai, Attila

2017-01-01

The simplest building blocks for quantum computations are the qubit-qubit quantum channels. In this paper, we analyze the structure of these channels via their Choi representation. The restriction of a quantum channel to the space of classical states (i.e. probability distributions) is called the underlying classical channel. The structure of quantum channels over a fixed classical channel is studied, the volume of general and unital qubit channels with respect to the Lebesgue measure is comp...

Performance Analysis of Iterative Channel Estimation and Multiuser Detection in Multipath DS-CDMA Channels

Science.gov (United States)

Li, Husheng; Betz, Sharon M.; Poor, H. Vincent

2007-05-01

This paper examines the performance of decision feedback based iterative channel estimation and multiuser detection in channel coded aperiodic DS-CDMA systems operating over multipath fading channels. First, explicit expressions describing the performance of channel estimation and parallel interference cancellation based multiuser detection are developed. These results are then combined to characterize the evolution of the performance of a system that iterates among channel estimation, multiuser detection and channel decoding. Sufficient conditions for convergence of this system to a unique fixed point are developed.

On the secrecy capacity of the MISO wiretap channel under imperfect channel estimation

KAUST Repository

Rezki, Zouheir

2014-12-01

We consider a wiretap channel consisting of a source with multiple antennas, a legitimate receiver and an eavesdropper with a single antenna each. The channels between the source and the receivers undergo fast fading. We assume that the transmitter, in addition to the statistics of both channels, is only aware of a noisy version of the CSI to the legitimate receiver referred to as main channel. The legitimate receiver is aware of both its instantaneous channel gain and the transmitter\\'s estimate of the main channel. On the other hand, the eavesdropper\\'s receiver, in addition to its instantaneous channel realization, is aware of the actual main CSI and the transmitter\\'s estimate as well. While the capacity of this channel is still open even with perfect CSI at the transmitter, we provide in this paper upper and lower bounds on the secrecy capacity. The upper bound is tighter than the one corresponding to perfect main CSI and the gap between the two upper bounds is characterized in function of the channel estimation error variance, at high-SNR. Furthermore, we show that our upper and lower bounds coincide in the case of no main CSI providing a trivial secrecy capacity.

Channel electron multipliers

International Nuclear Information System (INIS)

Seidman, A.; Avrahami, Z.; Sheinfux, B.; Grinberg, J.

1976-01-01

A channel electron multiplier is described having a tubular wall coated with a secondary-electron emitting material and including an electric field for accelerating the electrons, the electric field comprising a plurality of low-resistive conductive rings each alternating with a high-resistive insulating ring. The thickness of the low-resistive rings is many times larger than that of the high-resistive rings, being in the order of tens of microns for the low-resistive rings and at least one order of magnitude lower for the high-resistive rings; and the diameter of the channel tubular walls is also many times larger than the thickness of the high-resistive rings. Both single-channel and multiple-channel electron multipliers are described. A very important advantage, particularly in making multiple-channel multipliers, is the simplicity of the procedure that may be used in constructing such multipliers. Other operational advantages are described

A metabonomic evaluation of the monocrotaline-induced sinusoidal obstruction syndrome (SOS) in rats

Energy Technology Data Exchange (ETDEWEB)

Conotte, R.; Colet, J.-M., E-mail: jean-marie.colet@umons.ac.be

2014-04-15

The main curative treatment of colorectal cancer remains the surgery. However, when metastases are suspected, surgery is followed by a preventive chemotherapy using oxaliplatin which, unfortunately, may cause liver sinusoidal obstruction syndrome (SOS). Such hepatic damage is barely detected during or after chemotherapy due to a lack of effective diagnostic procedures, but liver biopsy. The primary objective of the present study was to identify potential early diagnosis biomarkers of SOS using a metabonomic approach. SOS was induced in rats by monocrotaline, a prototypical toxic substance. {sup 1}H NMR spectroscopy analysis of urine samples collected from rats treated with monocrotaline showed significant metabolic changes as compared to controls. During a first phase, cellular protective mechanisms such as an increased synthesis of GSH (reduced taurine) and the recruitment of cell osmolytes in the liver (betaine) were seen. In the second phase, the disturbance of the urea cycle (increased ornithine and urea reduction) leading to the depletion of NO, the alteration in the GSH synthesis (increased creatine and GSH precursors (glutamate, dimethylglycine and sarcosine)), and the liver necrosis (decrease taurine and increase creatine) all indicate the development of SOS. - Highlights: • Urine metabonomic profiles of SOS have been identified. • Urine osmoprotectants and anti-oxidants indicated an initial liver protection. • Liver necrosis was demonstrated by increased urine levels of taurine and creatine. • NO depletion was suggested by changes in ornithine and urea.

Coherifying quantum channels

Science.gov (United States)

Korzekwa, Kamil; Czachórski, Stanisław; Puchała, Zbigniew; Życzkowski, Karol

2018-04-01

Is it always possible to explain random stochastic transitions between states of a finite-dimensional system as arising from the deterministic quantum evolution of the system? If not, then what is the minimal amount of randomness required by quantum theory to explain a given stochastic process? Here, we address this problem by studying possible coherifications of a quantum channel Φ, i.e., we look for channels {{{Φ }}}{ \\mathcal C } that induce the same classical transitions T, but are ‘more coherent’. To quantify the coherence of a channel Φ we measure the coherence of the corresponding Jamiołkowski state J Φ. We show that the classical transition matrix T can be coherified to reversible unitary dynamics if and only if T is unistochastic. Otherwise the Jamiołkowski state {J}{{Φ }}{ \\mathcal C } of the optimally coherified channel is mixed, and the dynamics must necessarily be irreversible. To assess the extent to which an optimal process {{{Φ }}}{ \\mathcal C } is indeterministic we find explicit bounds on the entropy and purity of {J}{{Φ }}{ \\mathcal C }, and relate the latter to the unitarity of {{{Φ }}}{ \\mathcal C }. We also find optimal coherifications for several classes of channels, including all one-qubit channels. Finally, we provide a non-optimal coherification procedure that works for an arbitrary channel Φ and reduces its rank (the minimal number of required Kraus operators) from {d}2 to d.

The Extended-Window Channel Estimator for Iterative Channel-and-Symbol Estimation

Directory of Open Access Journals (Sweden)

Barry John R

2005-01-01

Full Text Available The application of the expectation-maximization (EM algorithm to channel estimation results in a well-known iterative channel-and-symbol estimator (ICSE. The EM-ICSE iterates between a symbol estimator based on the forward-backward recursion (BCJR equalizer and a channel estimator, and may provide approximate maximum-likelihood blind or semiblind channel estimates. Nevertheless, the EM-ICSE has high complexity, and it is prone to misconvergence. In this paper, we propose the extended-window (EW estimator, a novel channel estimator for ICSE that can be used with any soft-output symbol estimator. Therefore, the symbol estimator may be chosen according to performance or complexity specifications. We show that the EW-ICSE, an ICSE that uses the EW estimator and the BCJR equalizer, is less complex and less susceptible to misconvergence than the EM-ICSE. Simulation results reveal that the EW-ICSE may converge faster than the EM-ICSE.

Generation and evolution of turbulence in an annulus between two concentric rotating cylinders

International Nuclear Information System (INIS)

Kataoka, K.; Deguchi, T.

1987-01-01

The objective of the present work is to observe the generation and spectral evolution of time-dependent wavy disturbances in the Taylor-Couette flow. It is well known that as the Reynolds number Re = R/sub i/Ω d/ν, based on the rotation speed (Ω: angular velocity) of the inner cylinder, is gradually increased, the following five dynamical transitions occur stepwise in sequence: laminar Couette flow → laminar Taylor vortex flow → wavy vortex flow → quasi-periodic wavy vortex flow → weakly turbulent wavy vortex flow → turbulent vortex flow. Time-dependent wavy disturbances appear when the transition to wavy vortex flow occurs as a result of instability of the laminar Taylor vortex flow. The disturbances are regularly periodic because it results from the azimuthally traveling waves. The next transition to the quasi-periodic wavy vortex flow is accompanied by the amplitude modulation of the wave motion. The first fundamental frequency f/sub 1/ comes from the passing frequency of the azimuthally traveling waves and the second fundamental frequency f/sub 2/ from the modulation frequency. When the transition to the weakly turbulent wavy vortex flow occurs, chaotic turbulence first appears, A spectral analysis is made to analyze the temporal variation in the local velocity gradient measured on both the inner and outer cylinder walls by using an electrochemical technique

Channel identification machines.

Science.gov (United States)

Lazar, Aurel A; Slutskiy, Yevgeniy B

2012-01-01

We present a formal methodology for identifying a channel in a system consisting of a communication channel in cascade with an asynchronous sampler. The channel is modeled as a multidimensional filter, while models of asynchronous samplers are taken from neuroscience and communications and include integrate-and-fire neurons, asynchronous sigma/delta modulators and general oscillators in cascade with zero-crossing detectors. We devise channel identification algorithms that recover a projection of the filter(s) onto a space of input signals loss-free for both scalar and vector-valued test signals. The test signals are modeled as elements of a reproducing kernel Hilbert space (RKHS) with a Dirichlet kernel. Under appropriate limiting conditions on the bandwidth and the order of the test signal space, the filter projection converges to the impulse response of the filter. We show that our results hold for a wide class of RKHSs, including the space of finite-energy bandlimited signals. We also extend our channel identification results to noisy circuits.

Channel Identification Machines

Directory of Open Access Journals (Sweden)

Aurel A. Lazar

2012-01-01

Full Text Available We present a formal methodology for identifying a channel in a system consisting of a communication channel in cascade with an asynchronous sampler. The channel is modeled as a multidimensional filter, while models of asynchronous samplers are taken from neuroscience and communications and include integrate-and-fire neurons, asynchronous sigma/delta modulators and general oscillators in cascade with zero-crossing detectors. We devise channel identification algorithms that recover a projection of the filter(s onto a space of input signals loss-free for both scalar and vector-valued test signals. The test signals are modeled as elements of a reproducing kernel Hilbert space (RKHS with a Dirichlet kernel. Under appropriate limiting conditions on the bandwidth and the order of the test signal space, the filter projection converges to the impulse response of the filter. We show that our results hold for a wide class of RKHSs, including the space of finite-energy bandlimited signals. We also extend our channel identification results to noisy circuits.

CHANNEL ESTIMATION TECHNIQUE

DEFF Research Database (Denmark)

2015-01-01

A method includes determining a sequence of first coefficient estimates of a communication channel based on a sequence of pilots arranged according to a known pilot pattern and based on a receive signal, wherein the receive signal is based on the sequence of pilots transmitted over the communicat......A method includes determining a sequence of first coefficient estimates of a communication channel based on a sequence of pilots arranged according to a known pilot pattern and based on a receive signal, wherein the receive signal is based on the sequence of pilots transmitted over...... the communication channel. The method further includes determining a sequence of second coefficient estimates of the communication channel based on a decomposition of the first coefficient estimates in a dictionary matrix and a sparse vector of the second coefficient estimates, the dictionary matrix including...... filter characteristics of at least one known transceiver filter arranged in the communication channel....

Research on Cost Information Sharing and Channel Choice in a Dual-Channel Supply Chain

Directory of Open Access Journals (Sweden)

Huihui Liu

2016-01-01

Full Text Available Many studies examine information sharing in an uncertain demand environment in a supply chain. However there is little literature on cost information sharing in a dual-channel structure consisting of a retail channel and a direct sales channel. Assuming that the retail sale cost and direct sale cost are random variables with a general distribution, the paper investigates the retailer’s choice on cost information sharing in a Bertrand competition model. Based on the equilibrium outcome of information sharing, the manufacturer’s channel choice is discussed in detail. Our paper provides several interesting conclusions. In both single- and dual-channel structures, the retailer has little motivation to share its private cost information which is verified to be valuable for the manufacturer. When the cost correlation between the two channels increases, our analyses show that the manufacturer’s profit improves. However, when channel choice is involved, the value of information could play a different role. The paper finds that a dual-channel structure can benefit the manufacturer only when the cost correlation is sufficiently low. In addition, if the cost correlation is weak, the cost fluctuation will bring out the advantage of a dual-channel structure and adding a new direct channel will help in risk pooling.

Use of navigation channels by Lake Sturgeon: Does channelization increase vulnerability of fish to ship strikes?

Directory of Open Access Journals (Sweden)

Darryl W Hondorp

Full Text Available Channelization for navigation and flood control has altered the hydrology and bathymetry of many large rivers with unknown consequences for fish species that undergo riverine migrations. In this study, we investigated whether altered flow distributions and bathymetry associated with channelization attracted migrating Lake Sturgeon (Acipenser fulvescens into commercial navigation channels, potentially increasing their exposure to ship strikes. To address this question, we quantified and compared Lake Sturgeon selection for navigation channels vs. alternative pathways in two multi-channel rivers differentially affected by channelization, but free of barriers to sturgeon movement. Acoustic telemetry was used to quantify Lake Sturgeon movements. Under the assumption that Lake Sturgeon navigate by following primary flow paths, acoustic-tagged Lake Sturgeon in the more-channelized lower Detroit River were expected to choose navigation channels over alternative pathways and to exhibit greater selection for navigation channels than conspecifics in the less-channelized lower St. Clair River. Consistent with these predictions, acoustic-tagged Lake Sturgeon in the more-channelized lower Detroit River selected the higher-flow and deeper navigation channels over alternative migration pathways, whereas in the less-channelized lower St. Clair River, individuals primarily used pathways alternative to navigation channels. Lake Sturgeon selection for navigation channels as migratory pathways also was significantly higher in the more-channelized lower Detroit River than in the less-channelized lower St. Clair River. We speculated that use of navigation channels over alternative pathways would increase the spatial overlap of commercial vessels and migrating Lake Sturgeon, potentially enhancing their vulnerability to ship strikes. Results of our study thus demonstrated an association between channelization and the path use of migrating Lake Sturgeon that could prove

Characterization of Wet Air Plasma Jet Powered by Sinusoidal High Voltage and Nanosecond Pulses for Plasma Agricultural Application

Science.gov (United States)

Takashima, Keisuke; Shimada, Keisuke; Konishi, Hideaki; Kaneko, Toshiro

2015-09-01

Not only for the plasma sterilization but also for many of plasma life-science applications, atmospheric pressure plasma devices that allowed us to control its state and reactive species production are deserved to resolve the roles of the chemical species. Influence of the hydroxyl radical and ozone on germination of conidia of a strawberry pathogen is presented. Water addition to air plasma jet significantly improves germination suppression performance, while measured reactive oxygen species (ROS) are reduced. Although the results show a negative correlation between ROS and the germination suppression, this infers the importance of chemical composition generated by plasma. For further control of the plasma product, a plasma jet powered by sinusoidal high voltage and nanosecond pulses is developed and characterized with the voltage-charge Lissajous. Control of breakdown phase and discharge power by pulse-imposed phase is presented. This work is supported by JSPS KAKENHI Grant-in-Aid for Young Scientists (B) Grant Number 15K17480 and Exploratory Research Grant Number 23644199.

Voltage-Gated Calcium Channels

Science.gov (United States)

Zamponi, Gerald Werner

Voltage Gated Calcium Channels is the first comprehensive book in the calcium channel field, encompassing over thirty years of progress towards our understanding of calcium channel structure, function, regulation, physiology, pharmacology, and genetics. This book balances contributions from many of the leading authorities in the calcium channel field with fresh perspectives from risings stars in the area, taking into account the most recent literature and concepts. This is the only all-encompassing calcium channel book currently available, and is an essential resource for academic researchers at all levels in the areas neuroscience, biophysics, and cardiovascular sciences, as well as to researchers in the drug discovery area.

Sinusoidal Obstruction Syndrome during Treatment for Wilms' Tumor: A Life-threatening Complication

Science.gov (United States)

Totadri, Sidharth; Trehan, Amita; Bansal, Deepak; Jain, Richa

2017-01-01

Context: Survival rates exceed 90% in Wilms' tumor (WT). Actinomycin-D (ACT-D) which is indispensable in the management of WT is associated with the development of sinusoidal obstruction syndrome (SOS), a potentially fatal complication. Aims: The aim is to study the presentation, management, and outcome of SOS complicating ACT-D administration in WT. Settings and Design: Retrospective file review conducted in a Pediatric Hematology-Oncology unit. Materials and Methods: Patients diagnosed and treated for WT from January 2012 to December 2015 were analyzed. SOS was diagnosed clinically, based on McDonalds criteria, requiring two of the following: jaundice, hepatomegaly and/or right upper quadrant pain, weight gain with or without ascites. Results: Of 104 patients treated, SOS occurred in 5 (4.8%). Age: 6 months to 5 years, 3 were girls. Tumor involved left kidney in 3, right in 1 and a horseshoe kidney in 1. Histopathology was consistent with WT in 4 and clear cell sarcoma kidney in 1. One had pulmonary metastases. Three developed SOS preoperatively and two during adjuvant chemotherapy. None received radiotherapy. Clinical manifestations comprised of jaundice, hepatomegaly, ascites/weight gain, respiratory distress, hypotension, and encephalopathy. Laboratory findings included thrombocytopenia, elevated serum transaminases, and coagulopathy. Treatment included fluid restriction, broad spectrum antibiotics, and transfusional support. Two children received N-acetyl cysteine infusion. Defibrotide was administered to two patients. Four recovered and one succumbed to multi-organ failure. Two patients were safely re-challenged with 50% doses of ACT-D. Conclusions: SOS is a clinical diagnosis. Systematic supportive care can enable complete recovery. Under close monitoring, re-challenge of ACT-D can be performed in gradually escalating doses. PMID:29333010

Evaluation channel performance in multichannel environments

NARCIS (Netherlands)

Gensler, S.; Dekimpe, M.; Skiera, B.

2007-01-01

Evaluating channel performance is crucial for actively managing multiple sales channels, and requires understanding the customers' channel preferences. Two key components of channel performance are (i) the existing customers' intrinsic loyalty to a particular channel and (ii) the channel's ability

Channel Choice: A Literature Review

DEFF Research Database (Denmark)

Østergaard Madsen, Christian; Kræmmergaard, Pernille

2015-01-01

The channel choice branch of e-government studies citizens’ and businesses’ choice of channels for interacting with government, and how government organizations can integrate channels and migrate users towards the most cost-efficient channels. In spite of the valuable contributions offered...

Reconfigurable virtual electrowetting channels.

Science.gov (United States)

Banerjee, Ananda; Kreit, Eric; Liu, Yuguang; Heikenfeld, Jason; Papautsky, Ian

2012-02-21

Lab-on-a-chip systems rely on several microfluidic paradigms. The first uses a fixed layout of continuous microfluidic channels. Such lab-on-a-chip systems are almost always application specific and far from a true "laboratory." The second involves electrowetting droplet movement (digital microfluidics), and allows two-dimensional computer control of fluidic transport and mixing. The merging of the two paradigms in the form of programmable electrowetting channels takes advantage of both the "continuous" functionality of rigid channels based on which a large number of applications have been developed to date and the "programmable" functionality of digital microfluidics that permits electrical control of on-chip functions. In this work, we demonstrate for the first time programmable formation of virtual microfluidic channels and their continuous operation with pressure driven flows using an electrowetting platform. Experimental, theoretical, and numerical analyses of virtual channel formation with biologically relevant electrolyte solutions and electrically-programmable reconfiguration are presented. We demonstrate that the "wall-less" virtual channels can be formed reliably and rapidly, with propagation rates of 3.5-3.8 mm s(-1). Pressure driven transport in these virtual channels at flow rates up to 100 μL min(-1) is achievable without distortion of the channel shape. We further demonstrate that these virtual channels can be switched on-demand between multiple inputs and outputs. Ultimately, we envision a platform that would provide rapid prototyping of microfluidic concepts and would be capable of a vast library of functions and benefitting applications from clinical diagnostics in resource-limited environments to rapid system prototyping to high throughput pharmaceutical applications.

KV7 potassium channels

DEFF Research Database (Denmark)

Stott, Jennifer B; Jepps, Thomas Andrew; Greenwood, Iain A

2014-01-01

Potassium channels are key regulators of smooth muscle tone, with increases in activity resulting in hyperpolarisation of the cell membrane, which acts to oppose vasoconstriction. Several potassium channels exist within smooth muscle, but the KV7 family of voltage-gated potassium channels have been...

Preservation of meandering river channels in uniformly aggrading channel belts

NARCIS (Netherlands)

Lageweg, W.I. van de; Schuurman, F.; Cohen, K.M.; Dijk, W.M. van; Shimizu, Y.; Kleinhans, M.G.

2016-01-01

Channel belt deposits from meandering river systems commonly display an internal architecture of stacked depositional features with scoured basal contacts due to channel and bedform migration across a range of scales. Recognition and correct interpretation of these bounding surfaces is essential to

Multi-channel service retailing: The effects of channel performance satisfaction on behavioral intentions.

NARCIS (Netherlands)

Birgelen, van M.; Jong, de A.; Ruyter, de J.C.

2006-01-01

Abstract The number of channels that retailers can use interchangeably to provide customer service has increased. We report on a study of clients of a large retail bank that investigates the channel performance satisfaction–behavioral intentions relationship when the traditional service channel

Channel Planform Dynamics Monitoring and Channel Stability Assessment in Two Sediment-Rich Rivers in Taiwan

Directory of Open Access Journals (Sweden)

Cheng-Wei Kuo

2017-01-01

Full Text Available Recurrent flood events induced by typhoons are powerful agents to modify channel morphology in Taiwan’s rivers. Frequent channel migrations reflect highly sensitive valley floors and increase the risk to infrastructure and residents along rivers. Therefore, monitoring channel planforms is essential for analyzing channel stability as well as improving river management. This study analyzed annual channel changes along two sediment-rich rivers, the Zhuoshui River and the Gaoping River, from 2008 to 2015 based on satellite images of FORMOSAT-2. Channel areas were digitized from mid-catchment to river mouth (~90 km. Channel stability for reaches was assessed through analyzing the changes of river indices including braid index, active channel width, and channel activity. In general, the valley width plays a key role in braided degree, active channel width, and channel activity. These indices increase as the valley width expands whereas the braid index decreases slightly close to the river mouth due to the change of river types. This downstream pattern in the Zhuoshui River was interrupted by hydraulic construction which resulted in limited changes downstream from the weir, due to the lack of water and sediment supply. A 200-year flood, Typhoon Morakot in 2009, induced significant changes in the two rivers. The highly active landscape in Taiwan results in very sensitive channels compared to other regions. An integrated Sensitivity Index was proposed for identifying unstable reaches, which could be a useful reference for river authorities when making priorities in river regulation strategy. This study shows that satellite image monitoring coupled with river indices analysis could be an effective tool to evaluate spatial and temporal changes in channel stability in highly dynamic river systems.

Distribution Channels Conflict and Management

OpenAIRE

Kiran, Dr Vasanth; Majumdar, Dr Mousumi; Kishore, Dr Krishna

2012-01-01

Relationships in distribution channels tend to be long-term oriented and members of the channel rely on each other to jointly realize their goals by serving buyers. Despite the channels focus on serving buyers, conflicts often arise between channel members because of each members self-interest. When conflicts arise, the perceptions of a channel member based on normative, rational/instrumental, or emotional reasoning will influence relational norms like trust and commitment that characterize t...

Petrographic observations suggestive of microbial mats from ...

Indian Academy of Sciences (India)

Ray 1977). 3. Petrographic observations. 3.1 General wavy lamination. Thin section studies of both Rampur and Bijaigarh. Shale show wavy and crinkly lamination of clayey and carbonaceous shales facies (figures 2, 3). Car- bonaceous films of clayey shale facies are very thin, continuous to discontinuous wavy crinkly lami ...

Quantum communication under channel uncertainty

International Nuclear Information System (INIS)

Noetzel, Janis Christian Gregor

2012-01-01

This work contains results concerning transmission of entanglement and subspaces as well as generation of entanglement in the limit of arbitrary many uses of compound- and arbitrarily varying quantum channels (CQC, AVQC). In both cases, the channel is described by a set of memoryless channels. Only forward communication between one sender and one receiver is allowed. A code is said to be ''good'' only, if it is ''good'' for every channel out of the set. Both settings describe a scenario, in which sender and receiver have only limited channel knowledge. For different amounts of information about the channel available to sender or receiver, coding theorems are proven for the CQC. For the AVQC, both deterministic and randomised coding schemes are considered. Coding theorems are proven, as well as a quantum analogue of the Ahlswede-dichotomy. The connection to zero-error capacities of stationary memoryless quantum channels is investigated. The notion of symmetrisability is defined and used for both classes of channels.

Electrophysiological characterisation of KCNQ channel modulators

DEFF Research Database (Denmark)

Schrøder, R.L

Potassium (K+) ion channels are ubiquitously expressed in mammalian cells, and each channel serves a precise physiological role due to its specific biophysical characteristics and expression pattern. A few K+ channels are targets for certain drugs, and in this thesis it is suggested that the KCNQ K......+ channels may be targets for neuroprotective, anti-epileptic and anti-nociceptive compounds. The importance of these channels is underscored by the fact that four out of five KCNQ channel subtypes are involved in severe human diseases. However, the pharmacology of the KCNQ channels is yet poorly understood...... as these channels were identified only recently. Therefore, there is a need for understanding the biophysical behavior and pharmacology of these ion channels. KCNQ channels belong to the group of voltage-activated K+ channels. The subfamily consists of KCNQ1-5, which is primarily expressed in the CNS, heart, ear...

Eight channel fast scalar

Energy Technology Data Exchange (ETDEWEB)

Waddoup, W D; Stubbs, R J [Durham Univ. (UK)

1977-11-01

An eight channel 64-bit scaler has been constructed with a static CMOS memory. Scaling frequencies are independently variable, at each channel, as are the number of bits/channel. The scaler, when used in conjunction with a multichannel charge to time converter results in a very flexible, gated multichannel ADC.

Automatic pickup of arrival time of channel wave based on multi-channel constraints

Science.gov (United States)

Wang, Bao-Li

2018-03-01

Accurately detecting the arrival time of a channel wave in a coal seam is very important for in-seam seismic data processing. The arrival time greatly affects the accuracy of the channel wave inversion and the computed tomography (CT) result. However, because the signal-to-noise ratio of in-seam seismic data is reduced by the long wavelength and strong frequency dispersion, accurately timing the arrival of channel waves is extremely difficult. For this purpose, we propose a method that automatically picks up the arrival time of channel waves based on multi-channel constraints. We first estimate the Jaccard similarity coefficient of two ray paths, then apply it as a weight coefficient for stacking the multichannel dispersion spectra. The reasonableness and effectiveness of the proposed method is verified in an actual data application. Most importantly, the method increases the degree of automation and the pickup precision of the channel-wave arrival time.

Functional modifications of acid-sensing ion channels by ligand-gated chloride channels.

Directory of Open Access Journals (Sweden)

Xuanmao Chen

Full Text Available Together, acid-sensing ion channels (ASICs and epithelial sodium channels (ENaC constitute the majority of voltage-independent sodium channels in mammals. ENaC is regulated by a chloride channel, the cystic fibrosis transmembrane conductance regulator (CFTR. Here we show that ASICs were reversibly inhibited by activation of GABA(A receptors in murine hippocampal neurons. This inhibition of ASICs required opening of the chloride channels but occurred with both outward and inward GABA(A receptor-mediated currents. Moreover, activation of the GABA(A receptors modified the pharmacological features and kinetic properties of the ASIC currents, including the time course of activation, desensitization and deactivation. Modification of ASICs by open GABA(A receptors was also observed in both nucleated patches and outside-out patches excised from hippocampal neurons. Interestingly, ASICs and GABA(A receptors interacted to regulate synaptic plasticity in CA1 hippocampal slices. The activation of glycine receptors, which are similar to GABA(A receptors, also modified ASICs in spinal neurons. We conclude that GABA(A receptors and glycine receptors modify ASICs in neurons through mechanisms that require the opening of chloride channels.

Coupling of SK channels, L-type Ca2+ channels, and ryanodine receptors in cardiomyocytes.

Science.gov (United States)

Zhang, Xiao-Dong; Coulibaly, Zana A; Chen, Wei Chun; Ledford, Hannah A; Lee, Jeong Han; Sirish, Padmini; Dai, Gu; Jian, Zhong; Chuang, Frank; Brust-Mascher, Ingrid; Yamoah, Ebenezer N; Chen-Izu, Ye; Izu, Leighton T; Chiamvimonvat, Nipavan

2018-03-16

Small-conductance Ca 2+ -activated K + (SK) channels regulate the excitability of cardiomyocytes by integrating intracellular Ca 2+ and membrane potentials on a beat-to-beat basis. The inextricable interplay between activation of SK channels and Ca 2+ dynamics suggests the pathology of one begets another. Yet, the exact mechanistic underpinning for the activation of cardiac SK channels remains unaddressed. Here, we investigated the intracellular Ca 2+ microdomains necessary for SK channel activation. SK currents coupled with Ca 2+ influx via L-type Ca 2+ channels (LTCCs) continued to be elicited after application of caffeine, ryanodine or thapsigargin to deplete SR Ca 2+ store, suggesting that LTCCs provide the immediate Ca 2+ microdomain for the activation of SK channels in cardiomyocytes. Super-resolution imaging of SK2, Ca v 1.2 Ca 2+ channel, and ryanodine receptor 2 (RyR2) was performed to quantify the nearest neighbor distances (NND) and localized the three molecules within hundreds of nanometers. The distribution of NND between SK2 and RyR2 as well as SK2 and Ca v 1.2 was bimodal, suggesting a spatial relationship between the channels. The activation mechanism revealed by our study paved the way for the understanding of the roles of SK channels on the feedback mechanism to regulate the activities of LTCCs and RyR2 to influence local and global Ca 2+ signaling.

Activation of TRPV1 channels inhibits mechanosensitive Piezo channel activity by depleting membrane phosphoinositides

Science.gov (United States)

Borbiro, Istvan; Badheka, Doreen; Rohacs, Tibor

2015-01-01

Capsaicin is an activator of the heat-sensitive TRPV1 (transient receptor potential vanilloid 1) ion channels and has been used as a local analgesic. We found that activation of TRPV1 channels with capsaicin either in dorsal root ganglion neurons or in a heterologous expression system inhibited the mechanosensitive Piezo1 and Piezo2 channels by depleting phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] and its precursor PI(4)P from the plasma membrane through Ca2+-induced phospholipase Cδ (PLCδ) activation. Experiments with chemically inducible phosphoinositide phosphatases and receptor-induced activation of PLCβ indicated that inhibition of Piezo channels required depletion of both PI(4)P and PI(4,5)P2. The mechanically activated current amplitudes decreased substantially in the excised inside-out configuration, where the membrane patch containing Piezo1 channels is removed from the cell. PI(4,5)P2 and PI(4)P applied to these excised patches inhibited this decrease. Thus, we concluded that Piezo channel activity requires the presence of phosphoinositides, and the combined depletion of PI(4,5)P2 or PI(4)P reduces channel activity. In addition to revealing a role for distinct membrane lipids in mechanosensitive ion channel regulation, these data suggest that inhibition of Piezo2 channels may contribute to the analgesic effect of capsaicin. PMID:25670203

New Channels, New Possibilities

DEFF Research Database (Denmark)

Pieterson, Willem; Ebbers, Wolfgang; Østergaard Madsen, Christian

2017-01-01

In this contribution we discuss the characteristics of what we call the fourth generation of public sector service channels: social robots. Based on a review of relevant literature we discuss their characteristics and place into multi-channel models of service delivery. We argue that social robots......-channel models of service delivery. This is especially relevant given the current lack of evaluations of such models, the broad range of channels available, and their different stages of deployment at governments around the world. Nevertheless, social robots offer an potentially very relevant addition...

Ion channelling in diamond

International Nuclear Information System (INIS)

Derry, T.E.

1978-06-01

Diamond is one of the most extreme cases from a channelling point of view, having the smallest thermal vibration amplitude and the lowest atomic number of commonly-encountered crystals. These are the two parameters most important for determining channelling behaviour. It is of consiberable interest therefore to see how well the theories explaining and predicting the channeling properties of other substance, succeed with diamond. Natural diamond, although the best available form for these experiments, is rather variable in its physical properties. Part of the project was devoted to considering and solving the problem of obtaining reproducible results representative of the ideal crystal. Channelling studies were performed on several good crystals, using the Rutherford backscattering method. Critical angles for proton channelling were measured for incident energies from 0.6 to 4.5 MeV, in the three most open axes and three most open planes of the diamond structure, and for α-particle channelling at 0.7 and 1.0 MeV (He + ) in the same axes and planes. For 1.0 MeV protons, the crystal temperature was varied from 20 degrees Celsius to 700 degrees Celsius. The results are presented as curves of backscattered yield versus angle in the region of each axis or plane, and summarised in the form of tables and graphs. Generally the critical angles, axial minimum yields, and temperature dependence are well predicted by the accepted theories. The most valuable overall conclusion is that the mean thermal vibration amplitude of the atoms in a crytical determines the critical approach distance to the channel walls at which an ion can remain channelled, even when this distance is much smaller than the Thomas-Fermi screening distance of the atomic potential, as is the case in diamond. A brief study was made of the radiation damage caused by α-particle bombardment, via its effect on the channelling phenomenon. It was possible to hold damage down to negligible levels during the

Ion Channel Trafficking: Control of Ion Channel Density as a Target for Arrhythmias?

Directory of Open Access Journals (Sweden)

Elise Balse

2017-10-01

Full Text Available The shape of the cardiac action potential (AP is determined by the contributions of numerous ion channels. Any dysfunction in the proper function or expression of these ion channels can result in a change in effective refractory period (ERP and lead to arrhythmia. The processes underlying the correct targeting of ion channels to the plasma membrane are complex, and have not been fully characterized in cardiac myocytes. Emerging evidence highlights ion channel trafficking as a potential causative factor in certain acquired and inherited arrhythmias, and therapies which target trafficking as opposed to pore block are starting to receive attention. In this review we present the current evidence for the mechanisms which underlie precise control of cardiac ion channel trafficking and targeting.

Customer Responses to Channel Migration Strategies Toward the E-channel

NARCIS (Netherlands)

Trampe, Debra; Konus, Umut; Verhoef, Peter C.

2014-01-01

Many firms stimulate customers to use the E-channel for services, which provokes various consumer responses to such limits on their freedom of choice. In a study on bank customers, we examine the extent of customer reactance in response to various E-channel migration strategies, the potential of

Multi-rate control over AWGN channels via analog joint source-channel coding

KAUST Repository

Khina, Anatoly; Pettersson, Gustav M.; Kostina, Victoria; Hassibi, Babak

2017-01-01

We consider the problem of controlling an unstable plant over an additive white Gaussian noise (AWGN) channel with a transmit power constraint, where the signaling rate of communication is larger than the sampling rate (for generating observations and applying control inputs) of the underlying plant. Such a situation is quite common since sampling is done at a rate that captures the dynamics of the plant and which is often much lower than the rate that can be communicated. This setting offers the opportunity of improving the system performance by employing multiple channel uses to convey a single message (output plant observation or control input). Common ways of doing so are through either repeating the message, or by quantizing it to a number of bits and then transmitting a channel coded version of the bits whose length is commensurate with the number of channel uses per sampled message. We argue that such “separated source and channel coding” can be suboptimal and propose to perform joint source-channel coding. Since the block length is short we obviate the need to go to the digital domain altogether and instead consider analog joint source-channel coding. For the case where the communication signaling rate is twice the sampling rate, we employ the Archimedean bi-spiral-based Shannon-Kotel'nikov analog maps to show significant improvement in stability margins and linear-quadratic Gaussian (LQG) costs over simple schemes that employ repetition.

Multi-rate control over AWGN channels via analog joint source-channel coding

KAUST Repository

Khina, Anatoly

2017-01-05

We consider the problem of controlling an unstable plant over an additive white Gaussian noise (AWGN) channel with a transmit power constraint, where the signaling rate of communication is larger than the sampling rate (for generating observations and applying control inputs) of the underlying plant. Such a situation is quite common since sampling is done at a rate that captures the dynamics of the plant and which is often much lower than the rate that can be communicated. This setting offers the opportunity of improving the system performance by employing multiple channel uses to convey a single message (output plant observation or control input). Common ways of doing so are through either repeating the message, or by quantizing it to a number of bits and then transmitting a channel coded version of the bits whose length is commensurate with the number of channel uses per sampled message. We argue that such “separated source and channel coding” can be suboptimal and propose to perform joint source-channel coding. Since the block length is short we obviate the need to go to the digital domain altogether and instead consider analog joint source-channel coding. For the case where the communication signaling rate is twice the sampling rate, we employ the Archimedean bi-spiral-based Shannon-Kotel\\'nikov analog maps to show significant improvement in stability margins and linear-quadratic Gaussian (LQG) costs over simple schemes that employ repetition.

Channel sialic acids limit hERG channel activity during the ventricular action potential.

Science.gov (United States)

Norring, Sarah A; Ednie, Andrew R; Schwetz, Tara A; Du, Dongping; Yang, Hui; Bennett, Eric S

2013-02-01

Activity of human ether-a-go-go-related gene (hERG) 1 voltage-gated K(+) channels is responsible for portions of phase 2 and phase 3 repolarization of the human ventricular action potential. Here, we questioned whether and how physiologically and pathophysiologically relevant changes in surface N-glycosylation modified hERG channel function. Voltage-dependent hERG channel gating and activity were evaluated as expressed in a set of Chinese hamster ovary (CHO) cell lines under conditions of full glycosylation, no sialylation, no complex N-glycans, and following enzymatic deglycosylation of surface N-glycans. For each condition of reduced glycosylation, hERG channel steady-state activation and inactivation relationships were shifted linearly by significant depolarizing ∼9 and ∼18 mV, respectively. The hERG window current increased significantly by 50-150%, and the peak shifted by a depolarizing ∼10 mV. There was no significant change in maximum hERG current density. Deglycosylated channels were significantly more active (20-80%) than glycosylated controls during phases 2 and 3 of action potential clamp protocols. Simulations of hERG current and ventricular action potentials corroborated experimental data and predicted reduced sialylation leads to a 50-70-ms decrease in action potential duration. The data describe a novel mechanism by which hERG channel gating is modulated through physiologically and pathophysiologically relevant changes in N-glycosylation; reduced channel sialylation increases hERG channel activity during the action potential, thereby increasing the rate of action potential repolarization.

Course on Ionic Channels

CERN Document Server

1986-01-01

This book is based on a series of lectures for a course on ionic channels held in Santiago, Chile, on November 17-20, 1984. It is intended as a tutorial guide on the properties, function, modulation, and reconstitution of ionic channels, and it should be accessible to graduate students taking their first steps in this field. In the presentation there has been a deliberate emphasis on the spe­ cific methodologies used toward the understanding of the workings and function of channels. Thus, in the first section, we learn to "read" single­ channel records: how to interpret them in the theoretical frame of kinetic models, which information can be extracted from gating currents in re­ lation to the closing and opening processes, and how ion transport through an open channel can be explained in terms of fluctuating energy barriers. The importance of assessing unequivocally the origin and purity of mem­ brane preparations and the use of membrane vesicles and optical tech­ niques in the stUGY of ionic channels a...

Quantum communication under channel uncertainty

Energy Technology Data Exchange (ETDEWEB)

Noetzel, Janis Christian Gregor

2012-09-06

This work contains results concerning transmission of entanglement and subspaces as well as generation of entanglement in the limit of arbitrary many uses of compound- and arbitrarily varying quantum channels (CQC, AVQC). In both cases, the channel is described by a set of memoryless channels. Only forward communication between one sender and one receiver is allowed. A code is said to be ''good'' only, if it is ''good'' for every channel out of the set. Both settings describe a scenario, in which sender and receiver have only limited channel knowledge. For different amounts of information about the channel available to sender or receiver, coding theorems are proven for the CQC. For the AVQC, both deterministic and randomised coding schemes are considered. Coding theorems are proven, as well as a quantum analogue of the Ahlswede-dichotomy. The connection to zero-error capacities of stationary memoryless quantum channels is investigated. The notion of symmetrisability is defined and used for both classes of channels.

XPM-induced degradation of multilevel phase modulated channel caused by neighboring NRZ modulated channels

DEFF Research Database (Denmark)

Jensen, Jesper Bevensee; Schiellerup, G.; Peucheret, Christophe

2008-01-01

The impact of XPM from NRZ modulated channels on an 8-level phase modulated channel in a WDM system was investigated. Requirements on launch power are found. 400 km transmission was achieved with negligible penalty.......The impact of XPM from NRZ modulated channels on an 8-level phase modulated channel in a WDM system was investigated. Requirements on launch power are found. 400 km transmission was achieved with negligible penalty....

On the secrecy capacity of the wiretap channel with imperfect main channel estimation

KAUST Repository

Rezki, Zouheir

2014-10-01

We study the secrecy capacity of fast fading channels under imperfect main channel (between the transmitter and the legitimate receiver) estimation at the transmitter. Lower and upper bounds on the ergodic secrecy capacity are derived for a class of independent identically distributed (i.i.d.) fading channels. The achievable rate follows from a standard wiretap code in which a simple on-off power control is employed along with a Gaussian input. The upper bound is obtained using an appropriate correlation scheme of the main and eavesdropper channels and is the best known upper bound so far. The upper and lower bounds coincide with recently derived ones in case of perfect main CSI. Furthermore, the upper bound is tight in case of no main CSI, where the secrecy capacity is equal to zero. Asymptotic analysis at high and low signal-to-noise ratio (SNR) is also given. At high SNR, we show that the capacity is bounded by providing upper and lower bounds that depend on the channel estimation error. At low SNR, however, we prove that the secrecy capacity is asymptotically equal to the capacity of the main channel as if there were no secrecy constraint. Numerical results are provided for i.i.d. Rayleigh fading channels.

Associations between levels of insulin-like growth factor 1 and sinusoidal obstruction syndrome after allogeneic haematopoietic stem cell transplantation

DEFF Research Database (Denmark)

Weischendorff, Sarah; Kielsen, Katrine; Sengeløv, H

2017-01-01

. We hypothesised that insulin-like growth factor-1 (IGF-1), a mediator of growth and proliferation of various tissues, may attenuate chemotherapy-induced tissue damage after HSCT. We prospectively measured plasma levels of IGF-1 and its binding protein 3 (IGFBP-3) in 41 patients undergoing...... myeloablative HSCT. IGF-1 and IGFBP-3 levels were inversely correlated with C-reactive protein and interleukin-6 levels post HSCT. In multivariate analyses, low levels of IGF-1 and IGFBP-3 before conditioning were associated with increased risk of developing sinusoidal obstruction syndrome (SOS; OR=5.00 per 1...... SDS decrease in IGF-1 (95% CI: 1.45-16.67), P=0.011 and OR=5.00 (1.37-20.00), P=0.015, respectively). Furthermore, low pre-transplant levels of IGF-1 and IGFBP-3 were associated with increased fluid retention during the first 21 days post transplant (OR=7.69 (95% CI: 1.59-33.33), P=0.012, and OR=2...

Cilia walls influence on peristaltically induced motion of magneto-fluid through a porous medium at moderate Reynolds number: Numerical study

Directory of Open Access Journals (Sweden)

R.E. Abo-Elkhair

2017-04-01

Full Text Available This article addresses, effects of a magneto-fluid through a Darcy flow model with oscillatory wavy walled whose inner surface is ciliated. The equations that governing the flow are modeled without using any approximations. Adomian Decomposition Method (ADM is used to evaluate the solution of our system of nonlinear partial differential equations. Stream function, velocity and pressure gradient components are obtained by using the vorticity formula. The effects for our arbitrary physical parameters on flow characteristics are analyzed by plotting diagrams and discussed in details. With the help of stream lines the trapping mechanism has also been discussed. The major outcomes for the ciliated channel walls are: The axial velocity is higher without a ciliated walls than that for a ciliated walls and an opposite behaviour is shown near the ciliated channel walls. The pressure gradients in both directions are higher for a ciliated channel walls. More numbers of the trapped bolus in the absent of the eccentricity of the cilia elliptic path.