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No description available.

No / The local parameters for kerosene–water upward flow are measured in a vertical pipe of 77.8 mm inner diameter at 4200 mm from the inlet(L/D = 54) using hot-film and dual optical probes. The effect of superficial water velocity and volumetric quality on radial distribution of two-phaseflow parameters is investigated. The results show the following: (i) the profiles of volume fraction and drop frequency are very similar, and increasing superficial water velocity at low volumetric qualities (<18.6%) change the profile from a convex shape with peak at the pipe centreline to uniform then to concave shape with peak near the wall; (ii) the profiles of drop cut chord change from a parabolic shape with peak at centreline for lows uperficial water velocities to a flat shape at higher superficial water velocity, and the area-averaged drop diameter decreases with higher superficial water velocities for all volumetric qualities; (iii) velocity profiles for both phases have shapes similar to single phase flow, flatter at higher values of superficial water velocity and volumetric quality and centreline peaked at low superficial water velocities and volumetric qualities; (iv) the slip velocity decreases with radial distance having a peak at centreline and zero values near the wall; (v) introducing kerosene drops into single phasewater flow results in a sharp increase in turbulent intensity, particularly at low water velocity, and the difference between the single phase and two-phase flow turbulence intensities decreases with higher superficial water velocities and (vi) the results show that interfacial area concentration increased with higher volumetric quality and higher number of bubbles thereby increases the contact area between the two phases.

No / This paper presents an integration procedure for the Reynolds-averaged Navier-Stokes equations for the determination of the distribution of the streamwise velocity using the vertical component. This procedure is dedicated to the outer region and central part of channels. The proposed model is applicable to both rough and smooth flow regimes, provided the velocity at the inner-outer boundary has been properly defined. To generate a simplified expansion, a number of hypotheses are proposed, focusing in particular on the analytical modeling of the vertical component by adopting a negligible viscosity. The proposed hypotheses are validated by the experimental data existing in the literature. The proposed simplified expansion is studied through a sensitivity analysis and proved consistent in regards to model experimental data. The proposed model seems capable of demonstrating different kinds of flows, including dip phenomenon flow patterns.

Yes / The Prandtl second kind of secondary current occurs in any narrow channel flow causing velocity dip in the flow velocity distribution by introducing the anisotropic turbulence into the flow. Here, a study was conducted to explain the occurrence of the secondary current in the outer region of flow velocity distribution using a universal expression. Started from the basic Navier-Stokes equation, the velocity profile derivation was accomplished in a universal way for both smooth and rough open channel flows. However, the outcome of the derived theoretical equation shows that the smooth and rough bed flows give different boundary conditions due to the different formation of log law for smooth and rough bed cases in the inner region of velocity distribution. Detailed comparison with a wide range of different measurement results from literatures (from smooth, rough and field measured data) evidences the capability of the proposed law to represent flow under all bed roughness conditions.

Inledning: Bandy är en vinterlagsport som innehåller både fysiska och tekniska krav. Till författarnas kännedom finns begränsat med vetenskaplig forskning om bandyspelares fysiska krav under match. Syfte: Syftet med denna studie var att beskriva manliga elitbandyspelares rörelseprofiler utifrån total distans, maximal hastighet, medelhastighet, speltid, hastighetszoner och acceleration under matchsituation mellan olika spelarpositioner. Metod: Datainsamlingen utfördes med tio hertz GPS-enheter på ett elitserielag i bandy från mellersta Sverige under säsongen 2014/15. Sex till åtta manliga elitbandyspelare studerades under elva matchtillfällen. Data analyserades både deskriptivt och genom envägs variansanalys (ANOVA) för att se signifikanta skillnader mellan spelarpositioner. Resultat: Mätningarna visade att spelarpositionen halv uppnådde den längsta totala distansen. Anfall hade den högsta medelhastigheten och utförde flest antal accelerationer per spelad minut. Spelarpositionen libero, back och halv hade den högsta speltiden och det var signifikanta skillnader till mittfält och anfall. Libero och back hade i de två långsammaste hastighetszonerna högst procent av total distans och utförde flest antal aktioner. Halv, mittfält och anfall hade i de två snabbaste hastighetszonerna högst procent av total distans och utförde flest antal aktioner. Slutsats: Detta indikerade att halv, mittfält och anfall hade likande resultat och hade de största fysiska kraven under match jämfört mot libero och back. / Introduction: Bandy is a team winter sport that contains both physical and technical demands. To the authors knowledge there is a limited scientific research on bandy player’s physical demands during the matches. The Aim: The aim of this study was to describe the male elite bandy players movement profiles based on total distance, maximum velocity, mean velocity, game time, velocity zones and acceleration during the match between different playing positions. Method: Data was collected with ten hertz GPS-units in an elite league team in bandy from middle of Sweden during the season 2014/15. Six to eight male elite bandy players were examined during eleven matches. Data were analyzed both descriptive and with one-way analysis of variance (ANOVA) to see significant differences between playing positions. Results: The measurements showed that the playing position half preformed the longest total distance. Forward preformed the highest mean velocity and performed the most number of accelerations per played minute. The playing positions libero, back and half had the highest game time and had significant differences to midfield and forward. Libero and back had the highest percent of the total distance, and performed the highest number of efforts in the two slowest velocity zones. Half, midfield and forward had the highest percent of the total distance and performed the highest number of efforts in the two fastest velocity zones. Conclusion: This indicated that half, midfield and forward had similar results and had the highest physical demands during the game compared to libero and back.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / The Compact Kinetic Energy Missile (CKEM) is currently being developed as the Army’s newest hypervelocity anti-tank missile. The project has recently transitioned from the Science and Technology Objective phase to the Advanced Technology Demonstration phase. Science and technology phase flight testing required the development of a miniature telemetry system for measuring the super sonic flight dynamics of the airframe, as well as, monitoring of the on board flight computer. Design challenges included a small mechanical envelope, limited power budget, numerous analog measurements, computer serial stream processing, and harsh launch and flight dynamics. Two versions of the system were developed in support of the partnership effort between the Army Missile Research, Development, and Engineering Center (AMRDEC) and industry. This paper will focus on the successful design, development, and flight tests of the CKEM telemetry system.

Doppler ultrasound imaging modalities arguably represent one of the most complex task performed (usually in real time) by ultrasound scanners. At the heart of these techniques lies the ability to detect and estimate soft tissues or blood motion within the human body. As they have become an invaluable tool in a wide range of clinical applications, these techniques have fostered an intensive effort of research in the field of signal processing for more than thirty years, with a push towards more accurate velocity or displacement estimation. Coded excitation has recently received a growing interest in the medical ultrasound community. The use of these techniques, originally developed in the radar field, makes it possible to increase the depth of penetration in B-mode imaging, while complying with safety standards. These standards impose strict limits on the peak acoustic intensity which can be transmitted into the body. Similar solutions were proposed in the early developments of Doppler flow-meters to improve the resolution / sensitivity trade-off from which typical pulsed Doppler systems suffer. This work discusses the potential improvements in resolution, sensitivity and accuracy achievable in the context of modern Doppler ultrasound imaging modalities (taken in its broadest sense, that is, all the techniques involving the estimation of displacements, or velocities). A theoretical framework is provided for discussing this potential improvements, along with simulations for a more quantitative assessment. Colour Flow Imaging (CFI) modalities are taken as the main reference technique for discussion, due to their historical importance, and their relevance in many clinical applications. The potential achievable improvement in accuracy is studied in the context of modern velocity estimation strategies, which can be broadly classified into narrowband estimators (such as the “Kasai” estimator still widely used in CFI) and time shift based wideband strategies (normalised crosscorrelation estimator used, for instance, in applications like strain or strain rate estimation, elastography, etc.). Finally, simulations and theoretical results are compared to experimental data obtained with a simple custom-designed experimental set-up, using a single-element transducer.

Time-resolved velocity information of carotid blood flow can be used to estimate haemodynamic conditions associated with carotid artery disease leading to stroke. MRI provides high-resolution measurement of such information but long scan time limits its clinical application in this area. In order to reduce scan time the MRI signal is often undersampled by skipping part of the signal during data acquisition. The aim of this work is to implement and evaluate different undersampling techniques for carotid velocity measurement on a 1.5 T clinical scanner. Most recent undersampling techniques assume spatial and temporal redundancies of real time-resolved MRI signal. In these techniques different undersampling strategies were proposed. Prior information or different assumptions of the nature of true signal were used in signal reconstruction. A brief review of these techniques and details of a representative technique, known as k-t BLAST, are presented. Another undersampling scheme, termed ktVD, is proposed to use predesigned undersampling patterns with variable sampling densities in both temporal and spatial dimensions. It aims to collect enough signal content at the signal acquisition stage and simplify signal reconstruction. Fidelity of the results from undersampled data is affected by many factors, such as signal dynamic content, degree of signal redundancy, noise level, degree of undersampling, undersampling patterns, and parameters of post-processing algorithms. Simulations and in vivo scans were conducted to investigate the effects of these factors in time-resolved 2D scans and time-resolved 3D scans. The results suggested velocity measurement became less reliable when they were obtained from less than 25% of the full signal. In time-resolved 3D scans the signal can be undersampled in either one or two spatial dimensions in addition to the temporal dimension. This allows more options in the design of undersampling patterns, which were tested in vivo. In order to test undersampling in three dimensions in high resolution 3D scans and measure velocity in three dimensions, a flow phantom was also scanned at high degrees of undersampling to test the proposed method.