WorldWideScience

Sample records for high flow rates

  1. Reserve, flowing electrolyte, high rate lithium battery

    Science.gov (United States)

    Puskar, M.; Harris, P.

    Flowing electrolyte Li/SOCl2 tests in single cell and multicell bipolar fixtures have been conducted, and measurements are presented for electrolyte flow rates, inlet and outlet temperatures, fixture temperatures at several points, and the pressure drop across the fixture. Reserve lithium batteries with flowing thionyl-chloride electrolytes are found to be capable of very high energy densities with usable voltages and capacities at current densities as high as 500 mA/sq cm. At this current density, a battery stack 10 inches in diameter is shown to produce over 60 kW of power while maintaining a safe operating temperature.

  2. High Frame Rate Synthetic Aperture 3D Vector Flow Imaging

    DEFF Research Database (Denmark)

    Villagómez Hoyos, Carlos Armando; Holbek, Simon; Stuart, Matthias Bo

    2016-01-01

    3-D blood flow quantification with high spatial and temporal resolution would strongly benefit clinical research on cardiovascular pathologies. Ultrasonic velocity techniques are known for their ability to measure blood flow with high precision at high spatial and temporal resolution. However......, current volumetric ultrasonic flow methods are limited to one velocity component or restricted to a reduced field of view (FOV), e.g. fixed imaging planes, in exchange for higher temporal resolutions. To solve these problems, a previously proposed accurate 2-D high frame rate vector flow imaging (VFI......) technique is extended to estimate the 3-D velocity components inside a volume at high temporal resolutions (

  3. Characteristics of Multiplexed Grooved Nozzles for High Flow Rate Electrospray

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyoung Tae; Kim, Woo Jin; Kim, Sang Soo [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

    2007-10-15

    The electrospray operated in the cone-jet mode can generate highly charged micro droplets in an almost uniform size at flow rates. Therefore, the multiplexing system which can retain the characteristics of the cone-jet mode is inevitable for the electrospray application. This experiment reports the multiplexed grooved nozzle system with the extractor. The effects of the grooves and the extractor on the performance of the electrospray were evaluated through experiments. Using the grooved nozzle, the stable cone-jet mode can be achieved at the each groove in the grooved mode. Furthermore, the number of nozzles per unit area is increased by the extractor. The multiplexing density is 12 jets per cm{sup 2} at 30 mm distance from the nozzle tip to the ground plate. The multiplexing system for the high flow rate electrospray is realized with the extractor which can diminish the space charge effect without sacrificing characteristics of the cone-jet mode.

  4. High Sensitivity Carbon Nanotubes Flow-Rate Sensors and Their Performance Improvement by Coating

    Directory of Open Access Journals (Sweden)

    Xing Yang

    2010-05-01

    Full Text Available A new type of hot-wire flow-rate sensor (HWFS with a sensing element made of a macro-sized carbon nanotube (CNT strand is presented in this study. An effective way to improve repeatability of the CNT flow-rate sensor by coating a layer of Al2O3 on the CNT surface is proposed. Experimental results show that due to the large surface-to-volume ratio and thin coated Al2O3 layer, the CNT flow-rate sensor has higher sensitivity and faster response than a conventional platinum (Pt HWFS. It is also demonstrated that the covered CNT flow-rate sensor has better repeatability than its bare counterpart due to insulation from the surrounding environment. The proposed CNT flow-rate sensor shows application potential for high-sensitivity measurement of flow rate.

  5. Quartz measurement in coal dust with high-flow rate samplers: laboratory study.

    Science.gov (United States)

    Lee, Taekhee; Lee, Eun Gyung; Kim, Seung Won; Chisholm, William P; Kashon, Michael; Harper, Martin

    2012-05-01

    A laboratory study was performed to measure quartz in coal dust using high-flow rate samplers (CIP10-R, GK2.69 cyclone, and FSP10 cyclone) and low-flow rate samplers [10-mm nylon and Higgins-Dewell type (BGI4L) cyclones] and to determine whether an increased mass collection from high-flow rate samplers would affect the subsequent quartz measurement by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) analytical procedures. Two different sizes of coal dusts, mass median aerodynamic diameter 4.48 μm (Coal Dust A) and 2.33 μm (Coal Dust B), were aerosolized in a calm air chamber. The mass of coal dust collected by the samplers was measured gravimetrically, while the mass of quartz collected by the samplers was determined by FTIR (NIOSH Manual of Analytical Method 7603) and XRD (NIOSH Manual of Analytical Method 7500) after one of two different indirect preparations. Comparisons between high-flow rate samplers and low-flow rate samplers were made by calculating mass concentration ratios of coal dusts, net mass ratios of coal dusts, and quartz net mass. Mass concentrations of coal dust from the FSP10 cyclone were significantly higher than those from other samplers and mass concentrations of coal dust from 10-mm nylon cyclone were significantly lower than those from other samplers, while the CIP10-R, GK2.69, and BGI4L samplers did not show significant difference in the comparison of mass concentration of coal dusts. The BGI4L cyclone showed larger mass concentration of ∼9% compared to the 10-mm nylon cyclone. All cyclones provided dust mass concentrations that can be used in complying with the International Standard Organization standard for the determination of respirable dust concentration. The amount of coal dust collected from the high-flow rate samplers was found to be higher with a factor of 2-8 compared to the low-flow rate samplers but not in direct proportion of increased flow rates. The high-flow rate samplers collected more quartz compared to

  6. Silica Measurement with High Flow Rate Respirable Size Selective Samplers: A Field Study.

    Science.gov (United States)

    Lee, Taekhee; Harper, Martin; Kashon, Michael; Lee, Larry A; Healy, Catherine B; Coggins, Marie A; Susi, Pam; O'Brien, Andrew

    2016-04-01

    High and low flow rate respirable size selective samplers including the CIP10-R (10 l min(-1)), FSP10 (11.2 l min(-1)), GK2.69 (4.4 l min(-1)), 10-mm nylon (1.7 l min(-1)), and Higgins-Dewell type (2.2 l min(-1)) were compared via side-by-side sampling in workplaces for respirable crystalline silica measurement. Sampling was conducted at eight different occupational sites in the USA and five different stonemasonry sites in Ireland. A total of 536 (268 pairs) personal samples and 55 area samples were collected. Gravimetric analysis was used to determine respirable dust mass and X-ray diffraction analysis was used to determine quartz mass. Ratios of respirable dust mass concentration, quartz mass concentration, respirable dust mass, and quartz mass from high and low flow rate samplers were compared. In general, samplers did not show significant differences greater than 30% in respirable dust mass concentration and quartz mass concentration when outliers (ratio 3.0) were removed from the analysis. The frequency of samples above the limit of detection and limit of quantification of quartz was significantly higher for the CIP10-R and FSP10 samplers compared to low flow rate samplers, while the GK2.69 cyclone did not show significant difference from low flow rate samplers. High flow rate samplers collected significantly more respirable dust and quartz than low flow rate samplers as expected indicating that utilizing high flow rate samplers might improve precision in quartz measurement. Although the samplers did not show significant differences in respirable dust and quartz concentrations, other practical attributes might make them more or less suitable for personal sampling.

  7. Accurate Angle Estimator for High-Frame-rate 2-D Vector Flow Imaging

    DEFF Research Database (Denmark)

    Villagómez Hoyos, Carlos Armando; Stuart, Matthias Bo; Lindskov Hansen, Kristoffer

    2016-01-01

    This paper presents a novel approach for estimating 2-D flow angles using a high-frame-rate ultrasound method. The angle estimator features high accuracy and low standard deviation (SD) over the full 360° range. The method is validated on Field II simulations and phantom measurements using the ex...

  8. Prediction of flow stress of 7017 aluminium alloy under high strain rate compression at elevated temperatures

    Institute of Scientific and Technical Information of China (English)

    Ravindranadh BOBBILI; B. RAMAKRISHNA; V. MADHU; A.K. GOGIA

    2015-01-01

    An artificial neural network (ANN) constitutive model and JohnsoneCook (JeC) model were developed for 7017 aluminium alloy based on high strain rate data generated from split Hopkinson pressure bar (SHPB) experiments at various temperatures. A neural network configuration consists of both training and validation, which is effectively employed to predict flow stress. Temperature, strain rate and strain are considered as inputs, whereas flow stress is taken as output of the neural network. A comparative study on JohnsoneCook (JeC) model and neural network model was performed. It was observed that the developed neural network model could predict flow stress under various strain rates and tem-peratures. The experimental stressestrain data obtained from high strain rate compression tests using SHPB over a range of temperatures (25?e300 ?C), strains (0.05e0.3) and strain rates (1500e4500 s?1) were employed to formulate JeC model to predict the flow stress behaviour of 7017 aluminium alloy under high strain rate loading. The JeC model and the back-propagation ANN model were developed to predict the flow stress of 7017 aluminium alloy under high strain rates, and their predictability was evaluated in terms of correlation coefficient (R) and average absolute relative error (AARE). R and AARE for the J-C model are found to be 0.8461 and 10.624%, respectively, while R and AARE for the ANN model are 0.9995 and 2.58%, respectively. The predictions of ANN model are observed to be in consistent with the experimental data for all strain rates and temperatures.

  9. High frame rate synthetic aperture vector flow imaging for transthoracic echocardiography

    DEFF Research Database (Denmark)

    Villagómez Hoyos, Carlos Armando; Stuart, Matthias Bo; Bechsgaard, Thor

    2016-01-01

    This work presents the first in vivo results of 2-D high frame rate vector velocity imaging for transthoracic cardiac imaging. Measurements are made on a healthy volunteer using the SARUS experimental ultrasound scanner connected to an intercostal phased-array probe. Two parasternal long-axis view...... (PLAX) are obtained, one centred at the aortic valve and another centred at the left ventricle. The acquisition sequence was composed of 3 diverging waves for high frame rate synthetic aperture flow imaging. For verification a phantom measurement is performed on a transverse straight 5 mm diameter....... In-vivo acquisitions show complex flow patterns in the heart. In the aortic valve view, blood is seen exiting the left ventricle cavity through the aortic valve into the aorta during the systolic phase of the cardiac cycle. In the left ventricle view, blood flow is seen entering the left ventricle...

  10. Hydrodechlorination of TCE in a circulated electrolytic column at high flow rate.

    Science.gov (United States)

    Fallahpour, Noushin; Yuan, Songhu; Rajic, Ljiljana; Alshawabkeh, Akram N

    2016-02-01

    Palladium-catalytic hydrodechlorination of trichloroethylene (TCE) by cathodic H2 produced from water electrolysis has been tested. For a field in-well application, the flow rate is generally high. In this study, the performance of Pd-catalytic hydrodechlorination of TCE using cathodic H2 is evaluated under high flow rate (1 L min(-1)) in a circulated column system, as expected to occur in practice. An iron anode supports reduction conditions and it is used to enhance TCE hydrodechlorination. However, the precipitation occurs and high flow rate was evaluated to minimize its adverse effects on the process (electrode coverage, clogging, etc.). Under the conditions of 1 L min(-1) flow, 500 mA current, and 5 mg L(-1) initial TCE concentration, removal efficacy using iron anodes (96%) is significantly higher than by mixed metal oxide (MMO) anodes (66%). Two types of cathodes (MMO and copper foam) in the presence of Pd/Al2O3 catalyst under various currents (250, 125, and 62 mA) were used to evaluate the effect of cathode materials on TCE removal efficacy. The similar removal efficiencies were achieved for both cathodes, but more precipitation generated with copper foam cathode (based on the experiments done by authors). In addition to the well-known parameters such as current density, electrode materials, and initial TCE concentration, the high velocities of groundwater flow can have important implications, practically in relation to the flush out of precipitates. For potential field application, a cost-effective and sustainable in situ electrochemical process using a solar panel as power supply is being evaluated.

  11. A Study of the Critical Nozzle for Flow Rate Measurement of High-Pressure Hydrogen Gas

    Institute of Scientific and Technical Information of China (English)

    H.D.Kim; J.H.Lee; K.A.Park; T.Setoguchi; S.Matsuo

    2007-01-01

    The mass flow rate measurement using a critical nozzle shows the validity of the inviscid theory, indicating that the discharge coefficient increases and approaches unity as the Reynolds number increases under the ideal gas law.However, when the critical nozzle measures the mass flow rate of a real gas such as hydrogen at a pressure of hundreds bar, the discharge coefficient exceeds unity, and the real gas effects should be taken into account. The present study aims at investigating the flow features of the critical nozzle using high-pressured hydrogen gas. The axisymmetric, compressible Navier-Stokes computation is employed to simulate the critical nozzle flow, and a fully implicit finite volume method is used to discretize the governing equation system. The real gas effects are simulated to consider the intermolecular forces, which account for the possibility of liquefying hydrogen gas. The computational results are compared with past experimental data. It has been found that the coefficient of discharge for real gas can be corrected properly below unity adopting the real gas assumption.

  12. Bubbling at high flow rates in inviscid and viscous liquids (slags)

    Science.gov (United States)

    Engh, T. Abel; Nilmani, M.

    1988-02-01

    The behavior of gas discharging into melts at high velocities but still in the bubbling regime has been investigated in a laboratory modeling study for constant flow conditions. Air or helium was injected through a vertical tuyere into water, zinc-chloride, and aqueous glycerol solutions. High speed cinematography and pressure measurements in the tuyere have been carried out simultaneously. Pressure fluctuations at the injection point were monitored and correlated to the mode of bubble formation. The effects of high gas flow rates and high liquid viscosities have been examined in particular. Flow rates were employed up to 10-3 m3/s and viscosity to 0.5 Ns/m2. In order to attain a high gas momentum, the tuyere diameter was only 3 x 10-3 m. The experimental conditions and modeling liquids were chosen with special reference to the established practice of submerged gas injection to treat nonferrous slags. Such slags can be highly viscous. Bubble volume is smaller than that calculated from existing models such as those given by Davidson and Schüler10,11 due to the effect of gas momentum elongating the bubbles. On the other hand, viscosity tends to retard the bubble rise velocity, thus increasing volumes. To take elongation into account, a mathematical model is presented that assumes a prolate ellipsoidal shape of the bubbles. The unsteady potential flow equations for the liquid are solved for this case. Viscous effects are taken into account by noting that flow deviates from irrotational motion only in a thin boundary layer along the surface of the bubble. Thus, drag on the bubble can be obtained by calculating the viscous energy dissipation for potential flow past an ellipse. The time-dependent inertia coefficient for the ellipsoid is found by equating the vertical pressure increase inside and outside the bubble. This pressure change in the bubble is obtained by assuming that gas enters as a homogeneous jet and then calculating the stagnation pressure at the apex of

  13. Experimental Results of High Pressure and High Strain Rate Tantalum Flow Stress on Omega and NIF

    Science.gov (United States)

    Park, Hye-Sook; Arsenlis, A.; Barton, N.; Benedetti, L.; Huntington, C.; McNaney, J.; Orlikowski, D.; Prisbrey, S.; Remington, B.; Rudd, R.; Swift, D.; Weber, S.; Wehrenberg, C.; Comley, A.

    2015-11-01

    Understanding the high pressure, high strain rate plastic deformation dynamics of materials is an area of research of high interest to planetary formation dynamics, meteor impact dynamics, and inertial confinement fusion designs. Developing predictive theoretical and computational descriptions of such systems, however, has been a difficult undertaking. We have performed many experiments on Omega, LCLS and NIF to test Ta strength models at high pressures (~ up to 4 Mbar), high strain rates (~ 107 s-1) and high strains (>30%) under ramped compression conditions using Rayleigh-Taylor and Richtmyer-Meshkov instability properties. These experiments use plasma drive to ramp compress the sample to higher pressure without shock-melting. We also studied lattice level strength mechanisms under shocked compression using a diffraction-based technique. Our studies show that the strength mechanisms from macro to micro scales are different from the traditional strength model predictions and that they are loading path dependent. We will report the experimental results. Work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA273.

  14. High rates of gene flow by pollen and seed in oak populations across Europe.

    Directory of Open Access Journals (Sweden)

    Sophie Gerber

    Full Text Available Gene flow is a key factor in the evolution of species, influencing effective population size, hybridisation and local adaptation. We analysed local gene flow in eight stands of white oak (mostly Quercus petraea and Q. robur, but also Q. pubescens and Q. faginea distributed across Europe. Adult trees within a given area in each stand were exhaustively sampled (range [239, 754], mean 423, mapped, and acorns were collected ([17,147], 51 from several mother trees ([3], [47], 23. Seedlings ([65,387], 178 were harvested and geo-referenced in six of the eight stands. Genetic information was obtained from screening distinct molecular markers spread across the genome, genotyping each tree, acorn or seedling. All samples were thus genotyped at 5-8 nuclear microsatellite loci. Fathers/parents were assigned to acorns and seedlings using likelihood methods. Mating success of male and female parents, pollen and seed dispersal curves, and also hybridisation rates were estimated in each stand and compared on a continental scale. On average, the percentage of the wind-borne pollen from outside the stand was 60%, with large variation among stands (21-88%. Mean seed immigration into the stand was 40%, a high value for oaks that are generally considered to have limited seed dispersal. However, this estimate varied greatly among stands (20-66%. Gene flow was mostly intraspecific, with large variation, as some trees and stands showed particularly high rates of hybridisation. Our results show that mating success was unevenly distributed among trees. The high levels of gene flow suggest that geographically remote oak stands are unlikely to be genetically isolated, questioning the static definition of gene reserves and seed stands.

  15. Neural network modeling to evaluate the dynamic flow stress of high strength armor steels under high strain rate compression

    Institute of Scientific and Technical Information of China (English)

    Ravindranadh BOBBILI; V. MADHU; A.K. GOGIA

    2014-01-01

    An artificial neural network (ANN) constitutive model is developed for high strength armor steel tempered at 500 ?C, 600 ?C and 650 ?C based on high strain rate data generated from split Hopkinson pressure bar (SHPB) experiments. A new neural network configuration consisting of both training and validation is effectively employed to predict flow stress. Tempering temperature, strain rate and strain are considered as inputs, whereas flow stress is taken as output of the neural network. A comparative study on JohnsoneCook (JeC) model and neural network model is performed. It was observed that the developed neural network model could predict flow stress under various strain rates and tempering temperatures. The experimental stressestrain data obtained from high strain rate compression tests using SHPB, over a range of tempering temperatures (500e650 ?C), strains (0.05e0.2) and strain rates (1000e5500/s) are employed to formulate JeC model to predict the high strain rate deformation behavior of high strength armor steels. The J-C model and the back-propagation ANN model were developed to predict the high strain rate deformation behavior of high strength armor steel and their predictability is evaluated in terms of correlation coefficient (R) and average absolute relative error (AARE). R and AARE for the JeC model are found to be 0.7461 and 27.624%, respectively, while R and AARE for the ANN model are 0.9995 and 2.58%, respectively. It was observed that the predictions by ANN model are in consistence with the experimental data for all tempering temperatures.

  16. Nanoimprinted distributed feedback dye laser sensors for high frame rate refractometric imaging of dissolution and fluid flow

    DEFF Research Database (Denmark)

    Vannahme, Christoph; Sørensen, Kristian Tølbøl; Gade, Carsten;

    2015-01-01

    High frame rate refractometric dissolution and fluid flow monitoring in one and two dimensions of space with distributed feedback dye laser sensors is presented. The sensors provide both low detection limits and high spatial resolution. © 2015 OSA.......High frame rate refractometric dissolution and fluid flow monitoring in one and two dimensions of space with distributed feedback dye laser sensors is presented. The sensors provide both low detection limits and high spatial resolution. © 2015 OSA....

  17. Enabling high-rate electrochemical flow capacitors based on mesoporous carbon microspheres suspension electrodes

    Science.gov (United States)

    Tian, Meng; Sun, Yueqing; Zhang, Chuanfang (John); Wang, Jitong; Qiao, Wenming; Ling, Licheng; Long, Donghui

    2017-10-01

    Electrochemical flow capacitor (EFC) is a promising technology for grid energy storage, which combines the fast charging/discharging capability of supercapacitors with the scalable energy capacity of flow batteries. In this study, we report a high-power-density EFC using mesoporous carbon microspheres (MCMs) as suspension electrodes. By using a simple yet effective spray-drying technique, monodispersed MCMs with average particle size of 5 μm, high BET surface area of 1150-1267 m2 g-1, large pore volume of 2-4 cm3 g-1 and controllable mesopore size of 7-30 nm have been successfully prepared. The resultant MCMs suspension electrode shows excellent stability and considerable high capacitance of 100 F g-1 and good cycling ability (86% of initial capacitance after 10000 cycles). Specially, the suspension electrode exhibits excellent rate performance with 75% capacitance retention from 2 to 100 mV s-1, significantly higher than that of microporous carbon electrodes (20∼30%), due to the developed mesoporous channels facilitating for rapid ion diffusion. In addition, the electrochemical responses on both negative and positive suspension electrodes are studied, based on which an optimal capacitance matching between them is suggested for large-scale EFC unit.

  18. Flow and failure of an aluminium alloy from low to high temperature and strain rate

    Directory of Open Access Journals (Sweden)

    Sancho Rafael

    2015-01-01

    Full Text Available The mechanical behaviour of an aluminium alloy is presented in this paper. The study has been carried out to analyse the flow and failure of the aluminium alloy 7075-T73. An experimental study has been planned performing tests of un-notched and notched tensile specimens at low strain rates using a servo-hydraulic machine. High strain rate tests have been carried out using the same geometry in a Hopkinson Split Tensile Bar. The dynamic experiments at low temperature were performed using a cryogenic chamber, and the high temperature ones with a furnace, both incorporated to the Hopkinson bar. Testing temperatures ranged from − 50 ∘C to 100 ∘C and the strain rates from 10−4 s−1 to 600 s−1. The material behaviour was modelled using the Modified Johnson-Cook model and simulated using LS-DYNA. The results show that the Voce type of strain hardening is the most accurate for this material, while the traditional Johnson-Cook is not enough accurate to reproduce the necking of un-notched specimens. The failure criterion was obtained by means of the numerical simulations using the analysis of the stress triaxiality versus the strain to failure. The diameters at the failure time were measured using the images taken with an image camera, and the strain to failure was computed for un-notched and notched specimens. The numerical simulations show that the analysis of the evolution of the stress triaxiality is crucial to achieve accurate results. A material model using the Modified Johnson-Cook for flow and failure is proposed.

  19. Effects of Changes in Lung Volume on Oscillatory Flow Rate During High-Frequency Chest Wall Oscillation

    Directory of Open Access Journals (Sweden)

    Scott J Butcher

    2007-01-01

    Full Text Available BACKGROUND: The effectiveness of high-frequency chest wall oscillation (HFCWO in mucolysis and mucous clearance is thought to be dependant on oscillatory flow rate (Fosc. Therefore, increasing Fosc during HFCWO may have a clinical benefit.

  20. High-repetition-rate XeCl waveguide laser without gas flow

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, C.P.; Gordon C. III; Moutoulas, C.; Feldman, B.J.

    1987-03-01

    Operation of a microwave discharge XeCl laser at pulse-repetition rates extending to 8 kHz without flow of the laser gas is reported. Present limits on pulse-repetition rate appear to be imposed by thermally induced refractive-index gradients.

  1. Very-high-flow injection rate for upper abdominal CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Masashi; Minamiguti, Hiroki; Hagihira, Takami; Kishi, Kazushi; Sato, Morio [Wakayama Medical Coll. (Japan); Shioyama, Yasukazu; Okumura, Toshiyuki; Yamada, Kouji; Kawashima, Michihisa [Central Hospital and Cancer Center of Ibaraki Prefecture, Tomobe (Japan)

    2002-06-01

    The purpose of this study was to compare a very-high-flow injection-rate method (group A) and a conventional injection-rate method (group B) for visualization of upper abdominal arteries by multidetector helical computed tomography (MDHCT). The subjects were 240 patients suspected to have abdominal lesions. They were randomly assigned to group A (120 patients) and group B (120 patients). In group A, the bilateral medial cubital veins were punctured, and contrast medium was infused at a rate of 8.6-9.6 ml/s. In group B, the unilateral medial cubital vein was punctured, and contrast medium was infused at a rate of 2.0-3.0 ml/s. The quality of vascular visualization was graded as poor, good, or excellent by three radiologists. All visualizations of the celiac trunk (CE) and superior mesenteric artery (SMA) were graded as excellent in both group A and group B. Visualization grades of the subsegmental branches of the hepatic artery (HA), right gastric artery (RGA), cystic artery, dorsal pancreatic artery (DPA), and superior pancreaticoduodenal artery (SPDA) were good or excellent in 75% (paging method)/53.3% (three-dimensional method), 85%/30%, 77.7%/18.3%, 76.7%/28.3%, and 88.3%/42.5%, respectively, in group A, and 33.3%/11.7%, 46.7%/3.4%, 41.6%/5%, 55%/4.2%, and 72.5%/14.2%, respectively, in group B. The appearance rate of intrahepatic portal branches was 28.3% in group A and 66.7% in group B in the arterial dominant phase. Group A showed better visualization results than Group B in upper abdominal arteries according to MDHCT. (author)

  2. Feeding an infant with high arched palate by high flow rate bottle nipple.

    Science.gov (United States)

    Eren, Abdulkadir; Bilgin, Huseyin; Kara, Semra

    2015-01-01

    For infants with high arched palate, feeding is one of the most immediate challenges faced by parents and caretakers. General suggestions for feeding in infants with cleft palate may be adapted to infants with high arched palate. These include oral feeding facilitation techniques and special feeding tools. Here we present a newborn with a high arched palate and serious feeding problems who was fed easily by a large size and a large hole nipple, ordinarily used for infants older than 6 months, instead of specialized feeding equipment.

  3. A two-stage subsurface vertical flow constructed wetland for high-rate nitrogen removal.

    Science.gov (United States)

    Langergraber, Guenter; Leroch, Klaus; Pressl, Alexander; Rohrhofer, Roland; Haberl, Raimund

    2008-01-01

    By using a two-stage constructed wetland (CW) system operated with an organic load of 40 gCOD.m(-2).d(-1) (2 m2 per person equivalent) average nitrogen removal efficiencies of about 50% and average nitrogen elimination rates of 980 g N.m(-2).yr(-1) could be achieved. Two vertical flow beds with intermittent loading have been operated in series. The first stage uses sand with a grain size of 2-3.2 mm for the main layer and has a drainage layer that is impounded; the second stage sand with a grain size of 0.06-4 mm and a drainage layer with free drainage. The high nitrogen removal can be achieved without recirculation thus it is possible to operate the two-stage CW system without energy input. The paper shows performance data for the two-stage CW system regarding removal of organic matter and nitrogen for the two year operating period of the system. Additionally, its efficiency is compared with the efficiency of a single-stage vertical flow CW system designed and operated according to the Austrian design standards with 4 m2 per person equivalent. The comparison shows that a higher effluent quality could be reached with the two-stage system although the two-stage CW system is operated with the double organic load or half the specific surface area requirement, respectively. Another advantage is that the specific investment costs of the two-stage CW system amount to 1,200 EUR per person (without mechanical pre-treatment) and are only about 60% of the specific investment costs of the singe-stage CW system. IWA Publishing 2008.

  4. Development of a novel parallel-spool pilot operated high-pressure solenoid valve with high flow rate and high speed

    Science.gov (United States)

    Dong, Dai; Li, Xiaoning

    2015-03-01

    High-pressure solenoid valve with high flow rate and high speed is a key component in an underwater driving system. However, traditional single spool pilot operated valve cannot meet the demands of both high flow rate and high speed simultaneously. A new structure for a high pressure solenoid valve is needed to meet the demand of the underwater driving system. A novel parallel-spool pilot operated high-pressure solenoid valve is proposed to overcome the drawback of the current single spool design. Mathematical models of the opening process and flow rate of the valve are established. Opening response time of the valve is subdivided into 4 parts to analyze the properties of the opening response. Corresponding formulas to solve 4 parts of the response time are derived. Key factors that influence the opening response time are analyzed. According to the mathematical model of the valve, a simulation of the opening process is carried out by MATLAB. Parameters are chosen based on theoretical analysis to design the test prototype of the new type of valve. Opening response time of the designed valve is tested by verifying response of the current in the coil and displacement of the main valve spool. The experimental results are in agreement with the simulated results, therefore the validity of the theoretical analysis is verified. Experimental opening response time of the valve is 48.3 ms at working pressure of 10 MPa. The flow capacity test shows that the largest effective area is 126 mm2 and the largest air flow rate is 2320 L/s. According to the result of the load driving test, the valve can meet the demands of the driving system. The proposed valve with parallel spools provides a new method for the design of a high-pressure valve with fast response and large flow rate.

  5. Development of a Novel Parallel-spool Pilot Operated High-pressure Solenoid Valve with High Flow Rate and High Speed

    Institute of Scientific and Technical Information of China (English)

    DONG Dai; LI Xiaoning

    2015-01-01

    High-pressure solenoid valve with high flow rate and high speed is a key component in an underwater driving system. However, traditional single spool pilot operated valve cannot meet the demands of both high flow rate and high speed simultaneously. A new structure for a high pressure solenoid valve is needed to meet the demand of the underwater driving system. A novel parallel-spool pilot operated high-pressure solenoid valve is proposed to overcome the drawback of the current single spool design. Mathematical models of the opening process and flow rate of the valve are established. Opening response time of the valve is subdivided into 4 parts to analyze the properties of the opening response. Corresponding formulas to solve 4 parts of the response time are derived. Key factors that influence the opening response time are analyzed. According to the mathematical model of the valve, a simulation of the opening process is carried out by MATLAB. Parameters are chosen based on theoretical analysis to design the test prototype of the new type of valve. Opening response time of the designed valve is tested by verifying response of the current in the coil and displacement of the main valve spool. The experimental results are in agreement with the simulated results, therefore the validity of the theoretical analysis is verified. Experimental opening response time of the valve is 48.3 ms at working pressure of 10 MPa. The flow capacity test shows that the largest effective area is 126 mm2 and the largest air flow rate is 2320 L/s. According to the result of the load driving test, the valve can meet the demands of the driving system. The proposed valve with parallel spools provides a new method for the design of a high-pressure valve with fast response and large flow rate.

  6. The influence of N2 flow rate on Ar and Ti Emission in high-pressure magnetron sputtering system plasma

    Science.gov (United States)

    How, Soo Ren; Nayan, Nafarizal; Lias, Jais

    2017-03-01

    For ionized physical vapor deposition (known as IPVD) technique, investigation on the ionization mechanism of titanium atoms is very important during the deposition of titanium nitride (TiN) thin film using reactive magnetron sputtering plasma. The introduction of nitrogen gas into the chamber discharge leads to modifications of plasma parameters and ionization mechanism of transition species. In this work, an investigation on the influence of nitrogen flow rate on spectrum properties of argon and titanium during the deposition process have been carried out. The experimental configuration consists of OES and structure of magnetron sputtering device with the turbo molecular pump. A high-pressure magnetron sputtering plasma was used as plasma discharge chamber with various flow rate of nitrogen gas. Optical emission spectroscopy (OES) measurements were employed as plasma diagnostics tool in magnetron sputtering plasma operated at relatively high pressure. OES is a non-invasive plasma diagnostics method and that can detect the atomic and ionic emission during plasma discharge. The flow rate of the Ar and N2 gas are controlled by mass flow controller. The changes of relative emission for both neutral and ionic of argon as well as titanium were observed using optical spectrometer when the nitrogen gas is introduced into the discharged chamber. We found that the titanium emission decreased very rapidly with the flow rate of nitrogen. In addition, the argon emission slightly decreased with the flow rate of nitrogen.

  7. Intergenic DNA sequences from the human X chromosome reveal high rates of global gene flow

    Directory of Open Access Journals (Sweden)

    Wall Jeffrey D

    2008-11-01

    Full Text Available Abstract Background Despite intensive efforts devoted to collecting human polymorphism data, little is known about the role of gene flow in the ancestry of human populations. This is partly because most analyses have applied one of two simple models of population structure, the island model or the splitting model, which make unrealistic biological assumptions. Results Here, we analyze 98-kb of DNA sequence from 20 independently evolving intergenic regions on the X chromosome in a sample of 90 humans from six globally diverse populations. We employ an isolation-with-migration (IM model, which assumes that populations split and subsequently exchange migrants, to independently estimate effective population sizes and migration rates. While the maximum effective size of modern humans is estimated at ~10,000, individual populations vary substantially in size, with African populations tending to be larger (2,300–9,000 than non-African populations (300–3,300. We estimate mean rates of bidirectional gene flow at 4.8 × 10-4/generation. Bidirectional migration rates are ~5-fold higher among non-African populations (1.5 × 10-3 than among African populations (2.7 × 10-4. Interestingly, because effective sizes and migration rates are inversely related in African and non-African populations, population migration rates are similar within Africa and Eurasia (e.g., global mean Nm = 2.4. Conclusion We conclude that gene flow has played an important role in structuring global human populations and that migration rates should be incorporated as critical parameters in models of human demography.

  8. Prediction of flow stress of 7017 aluminium alloy under high strain rate compression at elevated temperatures

    National Research Council Canada - National Science Library

    Bobbili, Ravindranadh; Ramakrishna, B; Madhu, V; Gogia, A.K

    2015-01-01

    An artificial neural network (ANN) constitutive model and Johnson–Cook (J–C) model were developed for 7017 aluminium alloy based on high strain rate data generated from split Hopkinson pressure bar (SHPB...

  9. Oscillatory Characteristics of Flow Rate in Cyclone Chambers of High Relative Length

    Directory of Open Access Journals (Sweden)

    A. Orekhov

    2013-01-01

    Full Text Available The paper describes an experimental investigation pertaining to distribution of oscillatory and averaged tangential and axial velocities of turbulent flow in cyclone chambers of high relative length. It has been shown that as in the chambers of relatively small length (close to unit length general level of velocity pulsation intensity significantly exceeds the level observed in the chambers of analogous use with non-tightened-up heat carrier.

  10. Plane-wave transverse oscillation for high-frame-rate 2-D vector flow imaging.

    Science.gov (United States)

    Lenge, Matteo; Ramalli, Alessandro; Tortoli, Piero; Cachard, Christian; Liebgott, Hervé

    2015-12-01

    Transverse oscillation (TO) methods introduce oscillations in the pulse-echo field (PEF) along the direction transverse to the ultrasound propagation direction. This may be exploited to extend flow investigations toward multidimensional estimates. In this paper, the TOs are coupled with the transmission of plane waves (PWs) to reconstruct high-framerate RF images with bidirectional oscillations in the pulse-echo field. Such RF images are then processed by a 2-D phase-based displacement estimator to produce 2-D vector flow maps at thousands of frames per second. First, the capability of generating TOs after PW transmissions was thoroughly investigated by varying the lateral wavelength, the burst length, and the transmission frequency. Over the entire region of interest, the generated lateral wavelengths, compared with the designed ones, presented bias and standard deviation of -3.3 ± 5.7% and 10.6 ± 7.4% in simulations and experiments, respectively. The performance of the ultrafast vector flow mapping method was also assessed by evaluating the differences between the estimated velocities and the expected ones. Both simulations and experiments show overall biases lower than 20% when varying the beam-to-flow angle, the peak velocity, and the depth of interest. In vivo applications of the method on the common carotid and the brachial arteries are also presented.

  11. High-flow-velocity and shear-rate imaging by use of color Doppler optical coherence tomography.

    Science.gov (United States)

    van Leeuwen, T G; Kulkarni, M D; Yazdanfar, S; Rollins, A M; Izatt, J A

    1999-11-15

    Color Doppler optical coherence tomography (CDOCT) is capable of precise velocity mapping in turbid media. Previous CDOCT systems based on the short-time Fourier transform have been limited to maximum flow velocities of the order of tens of millimeters per second. We describe a technique, based on interference signal demodulation at multiple frequencies, to extend the physiological relevance of CDOCT by increasing the dynamic range of measurable velocities to hundreds of millimeters per second. The physiologically important parameter of shear rate is also derived from CDOCT measurements. The measured flow-velocity profiles and shear-rate distributions correlate very well with theoretical predictions. The multiple demodulation technique, therefore, may be useful to monitor blood flow in vivo and to identify regions with high and low shear rates.

  12. High-frame rate, fast neutron imaging of two-phase flow in a thin rectangular channel

    CERN Document Server

    Zboray, R; Dangendorf, V; Stark, M; Tittelmeier, K; Cortesi, M; Adams, R

    2015-01-01

    We have demonstrated the feasibility of performing high-frame-rate, fast neutron radiography of air-water two-phase flows in a thin channel with rectangular cross section. The experiments have been carried out at the accelerator facility of the Physikalisch-Technische Bundesanstalt. A polychromatic, high-intensity fast neutron beam with average energy of 6 MeV was produced by 11.5 MeV deuterons hitting a thick Be target. Image sequences down to 10 millisecond exposure times were obtained using a fast-neutron imaging detector developed in the context of fast-neutron resonance imaging. Different two-phase flow regimes such as bubbly slug and churn flows have been examined. Two phase flow parameters like the volumetric gas fraction, bubble size and bubble velocities have been measured. The first results are promising, improvements for future experiments are also discussed.

  13. Clinical effect of Diskus dry-powder inhaler at low and high inspiratory flow-rates in asthmatic children

    DEFF Research Database (Denmark)

    Nielsen, K G; Auk, I L; Bojsen, K

    1998-01-01

    In vitro studies with the Diskus inhaler at low and high flow rates show consistent doses of drug as fine particles ... at low (30 L x min[-1]) and high (90 L x min[-1]) flow rates. A pilot study in 129 children aged 3-10 yrs demonstrated that 99% of children of 3 yrs and above can generate a flow > or = 30 L x min(-1) through the device, while 26% performed > or = 90 L x min(-1). Eighteen children aged 8-15 yrs...... with exercise induced asthma inhaled placebo or salmeterol 50 microg at either 30 L x min(-1) or 90 L x min(-1). Exercise challenges were carried out 1 h and 12 h after dosing. The maximum percentage fall in forced expiratory volume in one second (FEVI) after exercise 12 h after treatment was significantly less...

  14. Model for high rate gas flows in deformable and reactive porous beds

    Energy Technology Data Exchange (ETDEWEB)

    Weston, A M

    1985-01-08

    This report presents the development of a one dimensional planar Lagrange hydrodynamic computer model which describes the processes preceding detonation. The model treats gas flow, deflagration, and compaction in a porous bed of reactive material. The early part of deflagration to detonation experiment with porous HMX is simulated. Sensitivity of the simulation calculation to ignition and burn rate parameters is illustrated and discussed. The effects of changing the mean particle size of the porous material are investigated. There is widespread interest in runaway reaction hazards that may be associated with porosity in propellant and explosive materials. Experimentally, such reactions are initiated and observed in long, thick walled hollow tubes, filled with a granular porous bed of reactive material. We will present comparisons with an experiment on porous HMX to illustrate details of the model and to point out what we believe are important features of the observed phenomenon. A geometric finite element cell is devised that allows gas to flow through a compacting matrix. The experimental simulation considers the DDT process from initial squib burn through the onset of general matrix deflagration (convective burning), to the development of a fully dense compaction wave. While this simulation did not calculate turnover to detonation, it did illustrate that the transition occurred as soon as the compaction wave became fully dense. It is shown that deflagration and gas permeation lags compaction at the time of transition. This suggests that the actual transition involves an additional compaction dependent process. 18 references, 20 figures, 3 tables.

  15. Design and Analysis of a High Force, Low Voltage and High Flow Rate Electro-Thermal Micropump

    Directory of Open Access Journals (Sweden)

    Ghader Yosefi

    2014-12-01

    Full Text Available This paper presents the design and simulation of an improved electro-thermal micromachined pump for drug delivery applications. Thermal actuators, which are a type of Micro Electro Mechanical system (MEMS device, are highly useful because of their ability to deliver with great force and displacement. Thus, our structure is based on a thermal actuator that exploits the Joule heating effect and has been improved using the springy length properties of MEMS chevron beams. The Joule heating effect results in a difference in temperature and therefore displacement in the beams (actuators. Simulation results show that a maximum force of 4.4 mN and a maximum flow rate of 16 μL/min can be obtained by applying an AC voltage as low as 8 V at different frequencies ranging from 1 to 32 Hz. The maximum temperature was a problem at the chevron beams and the center shaft. Thus, to locally increase the temperature of the chevron beams alone and not that of the pumping diaphragm: (1 The air gaps 2 μm underneath and above the device layer were optimized for heat transfer. (2 Release holes and providing fins were created at the center shaft and actuator, respectively, to decrease the temperature by approximately 10 °C. (3 We inserted and used a polymer tube to serve as an insulator and eliminate leakage problems in the fluidic channel.

  16. In Vivo High Frame Rate Vector Flow Imaging Using Plane Waves and Directional Beamforming

    DEFF Research Database (Denmark)

    Jensen, Jonas; Villagómez Hoyos, Carlos Armando; Stuart, Matthias Bo

    2016-01-01

    Directional beamforming (DB) estimates blood flowvelocities accurately when the flow angle is known. However, forautomatically finding the flow angle a computationally expensive approach is used. This work presents a method for estimating the flow angle using a combination of inexpensive transverse...

  17. Thermodynamic Characteristic Study of a High-temperature Flow-rate Control Valve for Fuel Supply of Scramjet Engines

    Institute of Scientific and Technical Information of China (English)

    ZENG Wen; TONG Zhizhong; LI Songjing; LI Hongzhou; ZHANG Liang

    2012-01-01

    Thermodynamic characteristics are of great importance for the performance of a high-temperature flow-rate control valve,as high-temperature environment may bring problems,such as blocking of spool and increasing of leakage,to the valve.In this paper,a high-temperature flow-rate control valve,pilot-controlled by a pneumatic servo system is developed to control the fuel supply for scramjet engines.After introducing the construction and working principle,the thermodynamic mathematical models of the valve are built based on the heat transfer methods inside the valve.By using different boundary conditions,different methods of simulations are carried out and compared.The steady-state and transient temperature field distribution inside the valve body are predicted and temperatures at five interested points are measured.By comparing the simulation and experimental results,a reasonable 3D finite element analysis method is suggested to predict the thermodynamic characteristics of the high-temperature flow-rate control valve.

  18. Low flow rates and high air throughput: Cross-flow blowers; Niedrige Stroemungsgeschwindigkeiten bei hohem Luftdurchsatz: Querstromventilatoren

    Energy Technology Data Exchange (ETDEWEB)

    Lutz, J. [ebm-papst Landshut GmbH (Germany)

    2006-05-15

    Cross-flow blowers are everywhere, in electric towel driers, heaters, night storage heaters, floor heating systems, and open chimneys. With a diameter of only 30 mm, they are compact and effective. (orig.)

  19. Effects of changes in lung volume on oscillatory flow rate during high-frequency chest wall oscillation

    OpenAIRE

    Scott J Butcher; Pasiorowski, Michal P; Jones, Richard L

    2007-01-01

    BACKGROUND: The effectiveness of high-frequency chest wall oscillation (HFCWO) in mucolysis and mucous clearance is thought to be dependant on oscillatory flow rate (Fosc). Therefore, increasing Fosc during HFCWO may have a clinical benefit.OBJECTIVES: To examine effects of continuous positive airway pressure (CPAP) on Fosc at two oscillation frequencies in healthy subjects and patients with airway obstruction.METHODS: Five healthy subjects and six patients with airway obstruction underwent 1...

  20. High rates of gene flow by pollen and seed in oak populations across Europe

    NARCIS (Netherlands)

    Gerber, S.; Chadoeuf, J.; Gugerli, F.; Lascoux, M.; Buiteveld, J.; Cottrell, J.; Dounavi, A.; Fineschi, S.; Forrest, L.; Fogelqvist, J.; Goicoechea, P.G.; Jensen, J.S.; Salvini, D.; Vendramin, G.G.; Kremer, A.

    2014-01-01

    Gene flow is a key factor in the evolution of species, influencing effective population size, hybridisation and local adaptation. We analysed local gene flow in eight stands of white oak (mostly Quercus petraea and Q. robur, but also Q. pubescens and Q. faginea) distributed across Europe. Adult tree

  1. Assessment of impact of high particulate concentration on peak expiratory flow rate of lungs of sand stone quarry workers.

    Science.gov (United States)

    Singh, Suresh Kumar; Chowdhary, G R; Purohit, Gopal

    2006-12-01

    This study was designed to assess the impact of high particulate concentration on peak expiratory flow rate of lungs of sand stone quarry workers. The workers were engaged in different types of activities such as drilling, loading and dressing. These different working conditions had different concentrations of RSPM, leading to different exposure levels in workers. It was found that exposure duration and exposure concentrations were the main factors responsible for damage to the respiratory tracts of the workers. The particles were deposited at various areas of the respiratory system and reduced the peak flow rate. It was also revealed from the study that most of the workers suffered from silicosis if the exposure duration was more than 20 years.

  2. Multi-rate mass transfer modeling of two-phase flow in highly heterogeneous fractured and porous media

    Science.gov (United States)

    Tecklenburg, Jan; Neuweiler, Insa; Carrera, Jesus; Dentz, Marco

    2016-05-01

    We study modeling of two-phase flow in highly heterogeneous fractured and porous media. The flow behaviour is strongly influenced by mass transfer between a highly permeable (mobile) fracture domain and less permeable (immobile) matrix blocks. We quantify the effective two-phase flow behavior using a multirate rate mass transfer (MRMT) approach. We discuss the range of applicability of the MRMT approach in terms of the pertinent viscous and capillary diffusion time scales. We scrutinize the linearization of capillary diffusion in the immobile regions, which allows for the formulation of MRMT in the form of a non-local single equation model. The global memory function, which encodes mass transfer between the mobile and the immobile regions, is at the center of this method. We propose two methods to estimate the global memory function for a fracture network with given fracture and matrix geometry. Both employ a scaling approach based on the known local memory function for a given immobile region. With the first method, the local memory function is calculated numerically, while the second one employs a parametric memory function in form of truncated power-law. The developed concepts are applied and tested for fracture networks of different complexity. We find that both physically based parameter estimation methods for the global memory function provide predictive MRMT approaches for the description of multiphase flow in highly heterogeneous porous media.

  3. Effect of the spray pattern, water flow rate, and cutting position on the cutting efficiency of high-speed dental handpieces.

    Science.gov (United States)

    Yang, Wen-jie; Sun, Jian

    2013-01-01

    The aim of this study was to evaluate the effect of the spray pattern, water flow rate, and cutting position on the cutting efficiency of high-speed dental handpieces. One- and three-port high-speed handpieces were selected. Cutting efficiency (mm/s) in different cutting positions was evaluated in vitro on machinable ceramic underwater flow rates of 15, 25, and 35 mL/min. Statistical analysis revealed significant differences in cutting efficiency for the various cutting positions and flow rates. The authors recommend multiport handpieces with a flow rate greater than 30 mL/min for use in clinical practice, especially during groove cutting.

  4. Optimum solar collector fluid flow rates

    DEFF Research Database (Denmark)

    Furbo, Simon; Shah, Louise Jivan

    1996-01-01

    the energy consumption of a normal ciculation pump in the solar heating system.Calculations showed that the highest thermal performances for small SDHW systems based on mantle tanks with constant volume flow rates in the solar collector loops are achieved if the flow rate is situated in the interval from 0...... to the temperature difference between the solar collector and the bottom of the mantle - an increase of about 1% of the thermal performance is possible.Finally, calculations showed that the highest thermal performance for large SDHW systems with constant volume flow rates in the solar collector loops are achieved....... The flow rate is increasing for increasing temperature.The flow rate at the high temperature level is typically 70 % greater than the flow rate at the low temperature level.Further, the energy consumption for the electronically controlled pump in a solar heating system will be somewhat smaller than...

  5. MHD interaction in an Electromagnetic Pump for high flow rate loop of ASTRID Sodium Fast Reactor secondary circuit -performances

    OpenAIRE

    Letout, S; Duterrail, Y; Fautrelle, Y; Medina, M. , il.; Rey, F.; Laffont, G.

    2015-01-01

    International audience; The present paper deals with the analysis of the performances of a very large Annular Linear Induction Pumps (ALIP) for liquid sodium. This pump is able to provide high flow rates (more than 7,000 m3.h-1 with a pressure discharge of about 3.7 bar). Dimensions of pumping channel under the active part are of an average diameter of 966 mm and a length of 4,500 mm. It’s a double sided inductor pump. On the base of an imposed 2D axisymmetric geometry, performances (discharg...

  6. MHD interaction in an Electromagnetic Pump for high flow rate loop of ASTRID Sodium Fast Reactor secondary circuit, behavior

    OpenAIRE

    Letout, S; Duterrail, Y; Fautrelle, Y; Medina, M. , il.; Rey, F.; Laffont, G.

    2015-01-01

    International audience; The present paper deals with the analysis of the behaviour of a very large Annular Linear Induction Pumps (ALIP) for liquid sodium. This pump is able to provide high flow rates (more than 7,000 m3/h with a pressure discharge of about 3.7 bar). Dimensions of pumping channel under the active part are of an average diameter of 966 mm and a length of 4,500 mm. The global and local stability of the pump are analyzed. It is found that in the nominal conditions, stable operat...

  7. Multi-rate mass transfer modeling of two-phase flow in highly heterogeneous fractured and porous media

    CERN Document Server

    Tecklenburg, Jan; Carrera, Jesus; Dentz, Marco

    2016-01-01

    We study modeling of two-phase flow in highly heterogeneous fractured and porous media. The flow behaviour is strongly influenced by mass transfer between a highly permeable (mobile) fracture domain and less permeable (immobile) matrix blocks. We quantify the effective two-phase flow behaviour using a multirate rate mass transfer (MRMT) approach. We discuss the range of applicability of the MRMT approach in terms of the pertinent viscous and capillary diffusion time scales. We scrutinize the linearization of capillary diffusion in the immobile regions, which allows for the formulation of MRMT in the form of a non-local single equation model. The global memory function, which encodes mass transfer between the mobile and the immobile regions, is at the center of this method. We propose two methods to estimate the global memory function for a fracture network with given fracture and matrix geometry. Both employ a scaling approach based on the known local memory function for a given immobile region. With the firs...

  8. Effect of blood flow rate on internal filtration in a high-flux dialyzer with polysulfone membrane.

    Science.gov (United States)

    Sakiyama, Ryoichi; Ishimori, Isamu; Akiba, Takashi; Mineshima, Michio

    2012-09-01

    Internal filtration/backfiltration (IF/BF) of a dialyzer depends on several parameters. This study evaluated the effect of the blood flow rate (Q (B)) on the internal filtration flow rate (Q (IF)) measured using Doppler ultrasonography for a high-flux dialyzer with a polysulfone membrane, APS-15E. In an in vitro study, bovine blood was circulated through the dialyzer, at a Q (B) of 100-350 mL/min. The clearances (CL) of creatinine, β(2)-microglobulin, and α(1)-microglobulin were then investigated. Q (IF) increased with the Q (B) value. A good correlation was obtained between Q (IF) and the pressure difference between the pressures at the inlet of the blood compartment and the pressure at the outlet of the dialysate compartment. The creatinine CL values strongly depended on Q (B) because molecular diffusion was dominant. The β(2)-microglobulin CL also depended on Q (B), because its removal rate seemed to be affected by both diffusive and convective transport caused by the IF/BF. An extremely low CL value was obtained for α(1)-microglobulin because of its low diffusivity and membrane fouling induced by proteins plugging the membrane. In conclusion, the IF/BF in the dialyzer strongly depends on Q (B). Furthermore, the dependence of the solute clearance on Q (B) decreased with increasing molecular size of the solute because of the decrease in diffusivity through the membrane.

  9. Photogrammetric Measurement of Recession Rates of Low Temperature Ablators Subjected to High Speed Flow

    Science.gov (United States)

    2011-06-01

    Fully Implicit Ablation and Thermal response code FRSI Felt Reusable Surface Insulation GIANTS Gauss -Seidel Implicit Aero thermodynamic Navier-Stokes...which point the shroud was released and allowed to progress downstream. Video cameras ( Canon L1 Hi-8 and Canon GL1) were used to capture the test at...Chen and Milos (Chen & Milos, Navier–Stokes Solutions with Finite Rate Ablation, 2005) utilized a code referred to as GIANTS ( Gauss -Seidel Implicit

  10. A new concept of high flow rate non-thermal plasma reactor for air treatment

    Energy Technology Data Exchange (ETDEWEB)

    Goujard, V.; Tatibouet, J.M. [Univ. de Poitiers, Poitiers (France). Centre national de la recherche scientifique, Laboratoire de Catalyse en Chimie Organique

    2010-07-01

    Although several non-thermal plasma reactors have been tested for air treatment at the laboratory scale, up-scaling to pilot or industrial scale remains a challenge because several parameters must be considered, such as hydrodynamic behaviour, maximum voltage in an industrial environment, and maintenance of the system. This paper presented a newly developed reactor which consists to a DBD plasma generated on individual supports that could be directly inserted in gas pipes where air flow must be treated. Elimination of 40 percent of 15 ppm of propene was obtained with a energy density as low as 10 J/L. The propene conversion increased when a manganese oxide based catalyst was used because the ozone produced by the plasma was used as an as an oxidant. A simple model of the plasma-catalyst reactor behaviour showed that more than 90 percent of propene conversion can be expected for an input energy density of 10 J/L and residual ozone concentration less than 100 ppb.

  11. Columbus Payloads Flow Rate Anomalies

    Science.gov (United States)

    Quaranta, Albino; Bufano, Gaetana; DePalo, Savino; Holt, James M.; Szigetvari, Zoltan; Palumberi, Sergio; Hinderer, S.

    2011-01-01

    The Columbus Active Thermal Control System (ATCS) is the main thermal bus for the pressurized racks working inside the European laboratory. One of the ATCS goals is to provide proper water flow rate to each payload (P/L) by controlling actively the pressure drop across the common plenum distribution piping. Overall flow measurement performed by the Water Pump Assembly (WPA) is the only flow rate monitor available at system level and is not part of the feedback control system. At rack activation the flow rate provided by the system is derived on ground by computing the WPA flow increase. With this approach, several anomalies were raised during these 3 years on-orbit, with the indication of low flow rate conditions on the European racks FSL, BioLab, EDR and EPM. This paper reviews the system and P/Ls calibration approach, the anomalies occurred, the engineering evaluation on the measurement approach and the accuracy improvements proposed, the on-orbit test under evaluation with NASA and finally discusses possible short and long term solutions in case of anomaly confirmation.

  12. Using Omega and NIF to Advance Theories of High-Pressure, High-Strain-Rate Tantalum Plastic Flow

    Science.gov (United States)

    Rudd, R. E.; Arsenlis, A.; Barton, N. R.; Cavallo, R. M.; Huntington, C. M.; McNaney, J. M.; Orlikowski, D. A.; Park, H.-S.; Prisbrey, S. T.; Remington, B. A.; Wehrenberg, C. E.

    2015-11-01

    Precisely controlled plasmas are playing an important role as both pump and probe in experiments to understand the strength of solid metals at high energy density (HED) conditions. In concert with theory, these experiments have enabled a predictive capability to model material strength at Mbar pressures and high strain rates. Here we describe multiscale strength models developed for tantalum and vanadium starting with atomic bonding and extending up through the mobility of individual dislocations, the evolution of dislocation networks and so on up to full scale. High-energy laser platforms such as the NIF and the Omega laser probe ramp-compressed strength to 1-5 Mbar. The predictions of the multiscale model agree well with the 1 Mbar experiments without tuning. The combination of experiment and theory has shown that solid metals can behave significantly differently at HED conditions; for example, the familiar strengthening of metals as the grain size is reduced has been shown not to occur in the high pressure experiments. Work performed under the auspices of the U.S. Dept. of Energy by Lawrence Livermore National Lab under contract DE-AC52-07NA273.

  13. Sinks for photosynthetic electron flow in green petioles and pedicels of Zantedeschia aethiopica: evidence for innately high photorespiration and cyclic electron flow rates.

    Science.gov (United States)

    Yiotis, Charilaos; Manetas, Yiannis

    2010-07-01

    A combination of gas exchange and various chlorophyll fluorescence measurements under varying O(2) and CO(2) partial pressures were used to characterize photosynthesis in green, stomata-bearing petioles of Zantedeschia aethiopica (calla lily) while corresponding leaves served as controls. Compared to leaves, petioles displayed considerably lower CO(2) assimilation rates, limited by both stomatal and mesophyll components. Further analysis of mesophyll limitations indicated lower carboxylating efficiencies and insufficient RuBP regeneration but almost similar rates of linear electron transport. Accordingly, higher oxygenation/carboxylation ratios were assumed for petioles and confirmed by experiments under non-photorespiratory conditions. Higher photorespiration rates in petioles were accompanied by higher cyclic electron flow around PSI, the latter being possibly linked to limitations in electron transport from intermediate electron carriers to end acceptors and low contents of PSI. Based on chlorophyll fluorescence methods, similar conclusions can be drawn for green pedicels, although gas exchange in these organs could not be applied due to their bulky size. Since our test plants were not subjected to stress we argue that higher photorespiration and cyclic electron flow rates are innate attributes of photosynthesis in stalks of calla lily. Active nitrogen metabolism may be inferred, while increased cyclic electron flow may provide the additional ATP required for the enhanced photorespiratory activity in petiole and pedicel chloroplasts and/or the decarboxylation of malate ascending from roots.

  14. Predicting the indicators of development of the Emba deposits with high visocity oils based on models of the flow rate and accumulated extraction

    Energy Technology Data Exchange (ETDEWEB)

    Dzhakiyev, K.T.

    1983-01-01

    Two types of curves of flow rate and accumulated extraction are identified on the basis of processing and analysis of actual data from the operation of the Emba deposits with increased and high viscosity oils. This made it possible to acquire two models of flow rate and accumulated extraction for deposits being developed in a water and pressure mode of mean activity and close to hard activity. An expression is acquired of the evaluation coefficient of extraction which is used in rating the annual (maximal) extraction and in designing a model of the flow rate and the accumulated extraction. A comparison of the actual curves of flow rate and accumulated extraction is given with models which are built based on an assigned volume of the extractable reserves and the parameters of the stratum and the fluids. A good convergence is noted between the calculated and factual curves of flow rate and accumulated extraction. The acquired models are recommended in rating the volumes of oil extraction by deposits which have left the stage of commercial exploration and by deposits which are entering the latter stage of development.

  15. Using the developed cross-flow filtration chip for collecting blood plasma under high flow rate condition and applying the immunoglobulin E detection

    Science.gov (United States)

    Yeh, Chia-Hsien; Hung, Chia-Wei; Wu, Chun-Han; Lin, Yu-Cheng

    2014-09-01

    This paper presents a cross-flow filtration chip for separating blood cells (white blood cells, red blood cells, and platelets) and obtaining blood plasma from human blood. Our strategy is to flow the sample solution in parallel to the membrane, which can generate a parallel shear stress to remove the clogging microparticles on the membrane, so the pure sample solution is obtained in the reservoir. The cross-flow filtration chip includes a cross-flow layer, a Ni-Pd alloy micro-porous membrane, and a reservoir layer. The three layers are packaged in a polymethylmethacrylate (PMMA) frame to create the cross-flow filtration chip. Various dilutions of the blood sample (original, 2 × , 3 × , 5 × , and 10×), pore sizes with different diameters (1 µm, 2 µm, 4 µm, 7 µm, and 10 µm), and different flow rates (1 mL/min, 3 mL/min, 5 mL/min, 7 mL/min, and 10 mL/min) are tested to determine their effects on filtration percentage. The best filtration percentage is 96.2% when the dilution of the blood sample is 10 × , the diameter of pore size of a Ni-Pd alloy micro-porous membrane is 2 µm, and the flow rate is 10 mL/min. Finally, for the clinical tests of the immunoglobulin E (IgE) concentration, the cross-flow filtration chip is used to filter the blood of the allergy patients to obtain the blood plasma. This filtered blood plasma is compared with that obtained using the conventional centrifugation based on the enzyme-linked immunosorbent assay. The results reveal that these two blood separation methods have similar detection trends. The proposed filtration chip has the advantages of low cost, short filtration time, and easy operation and thus can be applied to the separation of microparticles, cells, bacteria, and blood.

  16. PERMCAT experiments with tritium at high helium flow rates relevant for the tritium extraction systems using the CAPER facility at TLK

    Energy Technology Data Exchange (ETDEWEB)

    Bükki-Deme, András, E-mail: andras.buekki-deme@kit.edu; Demange, David; Le, Thanh-Long; Fanghänel, Eleonore; Simon, Karl-Heinz

    2016-11-01

    Highlights: • We examined PERMCAT reactor efficiency processing tritiated water at high Helium carrier flow rates. • We have found that – as expected from previous studies – that the swamping ratio (ratio between the impurity and purge side flow rates) has a key effect on the decontamination factors. • On the other hand, some rather unexpected effects tend to show that the limiting phenomena of such specific operation of PERMCAT reactors (at high impurity flow rates, thus short residence time) lies on the kinetics of the isotope exchange reactions. - Abstract: Experiments are still necessary to consolidate the processes retained for the Tritium Extraction Systems of the European ITER Test Blanket Modules (TBM). A PERMCAT reactor combines a catalyst promoting isotope exchange reactions and a Pd/Ag membrane allowing tritium recovery from complex gaseous mixtures containing tritium in different chemical forms. Originally developed for the Tokamak Exhaust Processing, the PERMCAT process is also candidate to detritiate the water arising from an adsorption column installed in the TBM ancillary systems. We discuss the results of an extensive experimental campaign using a PERMCAT reactor to process Q{sub 2}O containing impurity gas mixtures at high flow rates. Two different experimental configurations were studied, namely PERMCAT stand-alone, and PERMCAT in combination with a zeolite molecular sieve bed (MSB, previously loaded with Q{sub 2}O) under regeneration. On the one hand, many expected behaviors were observed, such as the key influence of the swamping ratio (ratio between the impurity and purge side flow rates) on the decontamination factors. On the other hand, some rather unexpected effects tend to show that the limiting phenomena of such specific operation of PERMCAT reactors (at high flow rates, thus short residence time) lies on the kinetics of the isotope exchange reactions.

  17. Exchange Rate Forecasting with Information Flow Approach

    Directory of Open Access Journals (Sweden)

    Irena Mačerinskienė

    2016-06-01

    Full Text Available The purpose of this article is to assess exchange rate forecasting possibilities with an information flow approach model. In the model the three types of information flows are distinguished: fundamental analysis information flow through particular macroeconomic determinants, microstructure approach information flow through dealer clients’ positioning data, technical analysis information flow through technical indicators. By using regression analysis it is shown that the composed model can forecast the exchange rate, the most significant information flows are distinguished. The results lead to further development of the information flow approach as a tool to forecast exchange rate fluctuations.

  18. Growth of silicon-doped Al0.6Ga0.4N with low carbon concentration at high growth rate using high-flow-rate metal organic vapor phase epitaxy reactor

    Science.gov (United States)

    Ikenaga, Kazutada; Mishima, Akira; Yano, Yoshiki; Tabuchi, Toshiya; Matsumoto, Koh

    2016-05-01

    The relationship between the carbon concentration and electrical characteristics of silicon-doped AlGaN (Al > 0.5) was investigated using a high-flow-rate metal organic vapor phase epitaxy (MOVPE) reactor. The carbon concentration and electrical properties of AlGaN (Al > 0.5) were measured as a function of the growth rate, V/III ratio, and growth temperature. The growth rate of Al0.6Ga0.4N was linearly controlled up to 7.2 µm/h under a constant ammonia (NH3) flow rate. However, a decrease in V/III ratio resulted in an increase in carbon concentration to 8 × 1017 cm-3. With increased growth temperature, the carbon concentration decreased to less than 2 × 1017 cm-3 without showing any reduction in growth rate. As a result, n-type Al0.6Ga0.4N with a carrier concentration of 5.4 × 1018 cm-3 and a resistivity of 2.2 × 10-2 Ω·cm was obtained.

  19. Tidal Modulation of Ice Flow on Kangerdlugssuaq and Helheim Glaciers, East Greenland, from High-Rate GPS Measurements

    DEFF Research Database (Denmark)

    Hamilton, G. S.; Stearns, L. A.; Elosegui, P.

    , and there was a detectable tidally-modulated variation in horizontal flow speed. Maximum uplift of the glacier was in phase with high tide. The absence of a lag indicates that the glacier tongue was responding to tidal height, and not to a progressive pressurization of the subglacial drainage system. Helheim Glacier also...... appears to have a short floating tongue, based on an analysis of GPS data collected in June-August 2006 at several stations located at increasing distances from the calving front. Glacier uplift was in phase with measured and modeled tidal height, but attenuated rapidly beyond ~~1 km from the terminus. We...

  20. Flow rate logging seepage meter

    Science.gov (United States)

    Reay, William G. (Inventor); Walthall, Harry G. (Inventor)

    1996-01-01

    An apparatus for remotely measuring and logging the flow rate of groundwater seepage into surface water bodies. As groundwater seeps into a cavity created by a bottomless housing, it displaces water through an inlet and into a waterproof sealed upper compartment, at which point, the water is collected by a collection bag, which is contained in a bag chamber. A magnet on the collection bag approaches a proximity switch as the collection bag fills, and eventually enables the proximity switch to activate a control circuit. The control circuit then rotates a three-way valve from the collection path to a discharge path, enables a data logger to record the time, and enables a pump, which discharges the water from the collection bag, through the three-way valve and pump, and into the sea. As the collection bag empties, the magnet leaves the proximity of the proximity switch, and the control circuit turns off the pump, resets the valve to provide a collection path, and restarts the collection cycle.

  1. HANARO core channel flow-rate measurement

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Heon Il; Chae, Hee Tae; Im, Don Soon; Kim, Seon Duk [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1996-06-01

    HANARO core consists of 23 hexagonal flow tubes and 16 cylindrical flow tubes. To get the core flow distribution, we used 6 flow-rate measuring dummy fuel assemblies (instrumented dummy fuel assemblies). The differential pressures were measured and converted to flow-rates using the predetermined relationship between AP and flow-rate for each instrumented dummy fuel assemblies. The flow-rate for the cylindrical flow channels shows +-7% relative errors and that for the hexagonal flow channels shows +-3.5% relative errors. Generally the flow-rates of outer core channels show smaller values compared to those of inner core. The channels near to the core inlet pipe and outlet pipes also show somewhat lower flow-rates. For the lower flow channels, the thermal margin was checked by considering complete linear power histories. From the experimental results, the gap flow-rate was estimated to be 49.4 kg/s (cf. design flow of 50 kg/s). 15 tabs., 9 figs., 10 refs. (Author) .new.

  2. Quantification of debris-flow erosion rates by using high-resolution multitemporal terrestrial and airborne LiDAR data in the Kaunertal/Eastern Alps, Austria

    Science.gov (United States)

    Neugirg, Fabian; Haas, Florian; Heckmann, Tobias; Hilger, Ludwig; Dusik, Jana-Marie; Becht, Michael

    2013-04-01

    Geomorphic processes in alpine high mountain areas show very high intensities. Not only high reliefs and steep slopes, but also the availability of recently exposed sediments in proglacial areas contribute to this fact. Furthermore the thawing and degradation of permafrost in high elevation zones trigger rock falls and debris flows in areas above and close to the glacier tongues, which provides for additional sediment input into the proglacial area. The work presented here is part of the interdisciplinary joint project PROSA (High-resolution measurements of morphodynamics in rapidly changing PROglacial Systems of the Alps) which deals with the quantification of the sediment budget of an alpine catchment, broken down by geomorphic process and accounting for glacial, fluvial and gravitative processes. The investigations are focused on the forefield of the Gepatschferner, Oetztal Alps, Austria which is overtowered by steep moraine slopes of the Little Ice Age glacial maximum. The rather poorly consolidated material of these moraine slopes leads to frequent occurrence of slope type debris flows. In order to quantify the activity of debris flows, high-resolution terrestrial laser scanning data of the lateral moraine slope of the Gepatschferner were acquired repeatedly from six different scanning positions. The resulting point clouds were used to derive high-resolution digital elevation models (DEMs) of the moraine slopes. Highly accurate co-registration of the multi-epoch LiDAR data was ensured by usage of permanently fixed reflectors on immobile bedrock faces within and next to the area investigated. For investigating larger debris flow events on the catchment scale, high-resolution multitemporal airborne LiDAR data were used to derive DEMs. Very accurate debris flow erosion and deposition rates can be obtained from DEMs of difference and a sediment budget can be calculated. A limit of detection threshold, based on the individual measuring errors of the device, was

  3. Exchange Rate Forecasting with Information Flow Approach

    OpenAIRE

    Irena Mačerinskienė; Andrius Balčiūnas

    2016-01-01

    The purpose of this article is to assess exchange rate forecasting possibilities with an information flow approach model. In the model the three types of information flows are distinguished: fundamental analysis information flow through particular macroeconomic determinants, microstructure approach information flow through dealer clients’ positioning data, technical analysis information flow through technical indicators. By using regression analysis it is shown that the composed model can for...

  4. Relationship of long-term highly active antiretroviral therapy on salivary flow rate and CD4 Count among HIV-infected patients

    Directory of Open Access Journals (Sweden)

    J Vijay Kumar

    2015-01-01

    Full Text Available Objectives: To determine if long-term highly active antiretroviral therapy (HAART therapy alters salivary flow rate and also to compare its relation of CD4 count with unstimulated and stimulated whole saliva. Materials and Methods: A cross-sectional study was performed on 150 individuals divided into three groups. Group I (50 human immunodeficiency virus (HIV seropositive patients, but not on HAART therapy, Group II (50 HIV-infected subjects and on HAART for less than 3 years called short-term HAART, Group III (50 HIV-infected subjects and on HAART for more than or equal to 3 years called long-term HAART. Spitting method proposed by Navazesh and Kumar was used for the measurement of unstimulated and stimulated salivary flow rate. Chi-square test and analysis of variance (ANOVA were used for statistical analysis. Results: The mean CD4 count was 424.78 ΁ 187.03, 497.82 ΁ 206.11 and 537.6 ΁ 264.00 in the respective groups. Majority of the patients in all the groups had a CD4 count between 401 and 600. Both unstimulated and stimulated whole salivary (UWS and SWS flow rates in Group I was found to be significantly higher than in Group II (P < 0.05. Unstimulated salivary flow rate between Group II and III subjects were also found to be statistically significant (P < 0.05. ANOVA performed between CD4 count and unstimulated and stimulated whole saliva in each group demonstrated a statistically significant relationship in Group II (P < 0.05. There were no significant results found between CD4 count and stimulated whole saliva in each groups. Conclusion:The reduction in CD4 cell counts were significantly associated with salivary flow rates of HIV-infected individuals who are on long-term HAART.

  5. Coriolis mass flow rate meters for low flows

    NARCIS (Netherlands)

    Mehendale, A.

    2008-01-01

    The accurate and quick measurement of small mass flow rates (~10 mg/s) of fluids is considered an “enabling technology��? in semiconductor, fine-chemical, and food & drugs industries. Flowmeters based on the Coriolis effect offer the most direct sensing of the mass flow rate, and for this reason do

  6. Coriolis mass flow rate meters for low flows

    NARCIS (Netherlands)

    Mehendale, Aditya

    2008-01-01

    The accurate and quick measurement of small mass flow rates (~10 mg/s) of fluids is considered an "enabling technology" in semiconductor, fine-chemical, and food & drugs industries. Flowmeters based on the Coriolis effect offer the most direct sensing of the mass flow rate, and for this reason do no

  7. Capital Flows, Exchange Rate Flexibility, and the Real Exchange Rate

    OpenAIRE

    Jean-Louis Combes; Patrick Plane; Tidiane Kinda

    2011-01-01

    This paper analyzes the impact of capital inflows and exchange rate flexibility on the real exchange rate in developing countries based on panel cointegration techniques. The results show that public and private flows are associated with a real exchange rate appreciation. Among private flows, portfolio investment has the highest appreciation effect-almost seven times that of foreign direct investment or bank loans-and private transfers have the lowest effect. Using a de facto measure of excha...

  8. Enhanced energy harvesting and analysis of a High Concentration Photovoltaic / Thermal System with support of Cooling fluid and Increased Mass Flow Rates

    Directory of Open Access Journals (Sweden)

    A S R Murty

    2016-04-01

    Full Text Available In this paper a high concentration photovoltaic (HCPV system is considered. A parabolic dish collector focuses the incident energy on to a triple junction solar system. High concentration ratios ranging from 10 x to 1000x increases the cell temperature, resulting in a decrease in electrical efficiency. Thermal analysis of a water based cooling system is modeled to enhance the electrical efficiency and also to study the thermal efficiency of such HCPV system. It is to be noted that with an increase in mass flow rate of water, the electrical efficiency increases and the thermal efficiency decreases. Finally, a comparison of efficiencies with and without cooling are presented.

  9. Electromechanically Actuated Valve for Controlling Flow Rate

    Science.gov (United States)

    Patterson, Paul

    2007-01-01

    A proposed valve for controlling the rate of flow of a fluid would include an electric-motor-driven ball-screw mechanism for adjusting the seating element of the valve to any position between fully closed and fully open. The motor would be of a type that can be electronically controlled to rotate to a specified angular position and to rotate at a specified rate, and the ball screw would enable accurate linear positioning of the seating element as a function of angular position of the motor. Hence, the proposed valve would enable fine electronic control of the rate of flow and the rate of change of flow. The uniqueness of this valve lies in a high degree of integration of the actuation mechanism with the flow-control components into a single, relatively compact unit. A notable feature of this integration is that in addition to being a major part of the actuation mechanism, the ball screw would also be a flow-control component: the ball screw would be hollow so as to contain part of the main flow passage, and one end of the ball screw would be the main seating valve element. The relationships among the components of the valve are best understood by reference to the figure, which presents meridional cross sections of the valve in the fully closed and fully open positions. The motor would be supported by a bracket bolted to the valve body. By means of gears or pulleys and a timing belt, motor drive would be transmitted to a sleeve that would rotate on bearings in the valve body. A ball nut inside the sleeve would be made to rotate with the sleeve by use of a key. The ball screw would pass through and engage the ball nut. A key would prevent rotation of the ball screw in the valve body while allowing the ball screw to translate axially when driven by the ball nut. The outer surface of the ball screw would be threaded only in a mid-length region: the end regions of the outer surface of the ball screw would be polished so that they could act as dynamic sealing surfaces

  10. High-rate nitrogen removal and microbial community of an up-flow anammox reactor with ceramics as biomass carrier.

    Science.gov (United States)

    Ren, Yuhui; Li, Dong; Li, Xiangkun; Yang, Liu; Ding, An; Zhang, Jie

    2014-10-01

    Nitrogen removal performance and responsible microbial community of anammox process at low temperatures, and long term effect of dissolved oxygen (DO) on the performance of anammox process were investigated in a biofilm reactor, which was operated at 33±1°C (159d) and 20±2°C (162d) with an influent DO concentration of 0.7-1.5mgL(-1). Nitrogen removal recovered to 70% after 2wk with the temperature drastically decreasing from 33±1°C to 20±2°C. At 20±2°C, the average effluent (NH4(+)-N+NO2(-)-N) concentration was 0.08±0.08mgL(-1) at a hydraulic retention time of 1.5h. A total nitrogen removal efficiency of the reactor of 1.0gNL(-1)d(-1) was obtained for up to one month while the nitrogen loading rate was 1.16gNL(-1)d(-1). Results of T-RFLP and 16S rRNA phylogenic analysis revealed that Candidatus Jettenia asiatica, as confirmed to adapt to low temperature, was considered to be responsible for the stable and high nitrogen removal performance.

  11. Solids flow rate measurement in dense slurries

    Energy Technology Data Exchange (ETDEWEB)

    Porges, K.G.; Doss, E.D.

    1993-09-01

    Accurate and rapid flow rate measurement of solids in dense slurries remains an unsolved technical problem, with important industrial applications in chemical processing plants and long-distance solids conveyance. In a hostile two-phase medium, such a measurement calls for two independent parameter determinations, both by non-intrusive means. Typically, dense slurries tend to flow in laminar, non-Newtonian mode, eliminating most conventional means that usually rely on calibration (which becomes more difficult and costly for high pressure and temperature media). These issues are reviewed, and specific solutions are recommended in this report. Detailed calculations that lead to improved measuring device designs are presented for both bulk density and average velocity measurements. Cross-correlation, chosen here for the latter task, has long been too inaccurate for practical applications. The cause and the cure of this deficiency are discussed using theory-supported modeling. Fluid Mechanics are used to develop the velocity profiles of laminar non-Newtonian flow in a rectangular duct. This geometry uniquely allows the design of highly accurate `capacitive` devices and also lends itself to gamma transmission densitometry on an absolute basis. An absolute readout, though of less accuracy, is also available from a capacitive densitometer and a pair of capacitive sensors yields signals suitable for cross-correlation velocity measurement.

  12. Development of means to augment peritoneal urea clearances: the synergistic effects of combining high dialysate temperature and high dialysate flow rates with dextrose and nitroprusside.

    Science.gov (United States)

    De Santo, N G; Capodicasa, G; Capasso, G; Giordano, C

    1981-11-01

    By combining: a) nitroprusside (4.5 mg/L); b) dextrose concentration of 42.5 gm/L; c) dialysate temperature of 42 degrees C and d) dialysate flow rates of 3.5 L/hour in seven uremic subjects on CAPD, it was possible to increase peritoneal urea clearance up to 35.6 +/- 3.8 ml/min/1.73 m2 (range 30.3 to 42.2). This effect in six out of seven cases was associated with a fall in blood pressure and an increase in heart rate. This study is the first which deals with a combination of these factors and demonstrates that this approach is easy to handle, does not require the use of mechanical devices, and is available at any bedside.

  13. Tidal Modulation of Ice Flow on Kangerdlugssuaq and Helheim Glaciers, East Greenland, from High-Rate GPS Measurements

    DEFF Research Database (Denmark)

    Hamilton, G. S.; Stearns, L. A.; Elosegui, P.

    Boundary conditions at the frontal margins of tidewater glaciers provide important constraints on the balance of forces affecting ice flow and iceberg calving. For many large outlet glaciers in Greenland, the type of boundary condition (floating vs grounded ice) is not well known, owing to limited...... periods of 2-5 days in July 2005, and June, July and August 2006. The data were post-processed using a Kalman predictive filter to yield epoch-by-epoch station positions and elevations. Modeled ocean tides are shown to have good agreement with the tide stage measured over ~~3 weeks in July-August 2006...... in Sermilik fjord, close to the terminus of Helheim Glacier. An analysis of ice vertical displacement and modeled ocean tide for Kangerdlugssuaq Glacier indicates the calving terminus was likely at near-flotation in July 2005. A tidal amplitude of ~~2.5 m produced an uplift of ~~2 m...

  14. Flow rate measurements by means of tracers

    Energy Technology Data Exchange (ETDEWEB)

    Mosetti, F. (Trieste Univ. (Italy). Istituto di Geodesia e Geofisica)

    The application of some sources of diffusion for the flow rate measurement of water or other fluids is here presented. The laminar instantaneous source, obtained in practice with easy devices, is very useful in river or channel measurements. The analysis of the measurements could supply the flow rate and the presence of water losses or recharges. The section of the channel can also be determined by such a method.

  15. Studies on pressure losses and flow rate optimization in vanadium redox flow battery

    Science.gov (United States)

    Tang, Ao; Bao, Jie; Skyllas-Kazacos, Maria

    2014-02-01

    Premature voltage cut-off in the operation of the vanadium redox flow battery is largely associated with the rise in concentration overpotential at high state-of-charge (SOC) or state-of-discharge (SOD). The use of high constant volumetric flow rate will reduce concentration overpotential, although potentially at the cost of consuming excessive pumping energy which in turn lowers system efficiency. On the other hand, any improper reduction in flow rate will also limit the operating SOC and lead to deterioration in battery efficiency. Pressure drop losses are further exacerbated by the need to reduce shunt currents in flow battery stacks that requires the use of long, narrow channels and manifolds. In this paper, the concentration overpotential is modelled as a function of flow rate in an effort to determine an appropriate variable flow rate that can yield high system efficiency, along with the analysis of pressure losses and total pumping energy. Simulation results for a 40-cell stack under pre-set voltage cut-off limits have shown that variable flow rates are superior to constant flow rates for the given system design and the use of a flow factor of 7.5 with respect to the theoretical flow rate can reach overall high system efficiencies for different charge-discharge operations.

  16. Visible-light active thin-film WO3 photocatalyst with controlled high-rate deposition by low-damage reactive-gas-flow sputtering

    Directory of Open Access Journals (Sweden)

    Nobuto Oka

    2015-10-01

    Full Text Available A process based on reactive gas flow sputtering (GFS for depositing visible-light active photocatalytic WO3 films at high deposition rates and with high film quality was successfully demonstrated. The deposition rate for this process was over 10 times higher than that achieved by the conventional sputtering process and the process was highly stable. Furthermore, Pt nanoparticle-loaded WO3 films deposited by the GFS process exhibited much higher photocatalytic activity than those deposited by conventional sputtering, where the photocatalytic activity was evaluated by the extent of decomposition of CH3CHO under visible light irradiation. The decomposition time for 60 ppm of CH3CHO was 7.5 times more rapid on the films deposited by the GFS process than on the films deposited by the conventional process. During GFS deposition, there are no high-energy particles bombarding the growing film surface, whereas the bombardment of the surface with high-energy particles is a key feature of conventional sputtering. Hence, the WO3 films deposited by GFS should be of higher quality, with fewer structural defects, which would lead to a decrease in the number of centers for electron-hole recombination and to the efficient use of photogenerated holes for the decomposition of CH3CHO.

  17. Vitreous flow rates through dual pneumatic cutters: effects of duty cycle and cut rate

    Directory of Open Access Journals (Sweden)

    Abulon DJK

    2015-02-01

    Full Text Available Dina Joy K Abulon Medical Affairs, Alcon Research, Ltd, Lake Forest, CA, USA Purpose: We aimed to investigate effects of instrument settings on porcine vitreous flow rates through dual pneumatic high-speed vitrectomy probes. Methods: The CONSTELLATION® Vision System was tested with 250, 450, and 650 mmHg of vacuum using six ULTRAVIT® vitrectomy probes of each diameter (25+®, 25, 23, and 20 gauge operated from 500 cuts per minute (cpm up to 5,000 cpm. Duty cycle modes tested included biased open, 50/50, and biased closed. Flow rates were calculated by assessing the change in weight of porcine eyes during vitreous aspiration. Volumetric flow rate was measured with a computer-connected electronic scale. Results: At lower cut rates, the biased open mode produced higher flow than did the 50/50 mode, which produced higher flow than did the biased closed mode. In the biased closed and 50/50 modes, vitreous flow rates tended to increase with increasing cut rate. Vitreous flow rates in the biased open duty cycle mode remained relatively constant across cut rates. Conclusion: Vitreous flow rates through dual pneumatic vitrectomy probes could be manipulated by changing the duty cycle modes on the vitrectomy system. Differences in duty cycle behavior suggest that high-speed cut rates of 5,000 cpm may optimize vitreous aspiration. Keywords: enhanced 25-gauge vitrectomy, 25-gauge vitrectomy, 20-gauge vitrectomy, 23-gauge vitrectomy, aspiration, Constellation Vision System

  18. Internal Flow of Contra-Rotating Small Hydroturbine at Off- Design Flow Rates

    Science.gov (United States)

    SHIGEMITSU, Toru; TAKESHIMA, Yasutoshi; OGAWA, Yuya; FUKUTOMI, Junichiro

    2016-11-01

    Small hydropower generation is one of important alternative energy, and enormous potential lie in the small hydropower. However, efficiency of small hydroturbines is lower than that of large one. Then, there are demands for small hydroturbines to keep high performance in wide flow rate range. Therefore, we adopted contra-rotating rotors, which can be expected to achieve high performance. In this research, performance of the contra-rotating small hydroturbine with 60mm casing diameter was investigated by an experiment and numerical analysis. Efficiency of the contra-rotating small hydroturbine was high in pico-hydroturbine and high efficiency could be kept in wide flow rate range, however the performance of a rear rotor decreased significantly in partial flow rates. Then, internal flow condition, which was difficult to measure experimentally, was investigated by the numerical flow analysis. Then, a relation between the performance and internal flow condition was considered by the numerical analysis result.

  19. Negative Policy Rates, Banking Flows and Exchange Rates

    OpenAIRE

    Khayat, Anwar

    2015-01-01

    Setting negative nominal rates is one of the unconventional policies implemented after the Great Recession to overcome the Zero Lower Bound. Using data from the euro area and Denmark, I assess the impact of introducing a negative interest rate on reserves. I find that it did put a depreciation pressure on the currency due to a reversal in banking flows. This effect is not only caused by policy differentials, but also by a distinct impact of going into negative territory from lowering interest...

  20. A new series of small turbochargers for high flow rates and high pressure ratios; Eine neue Serie von kleinen Turboladern fuer hohe Volumenstroeme und hohe Druckverhaeltnisse

    Energy Technology Data Exchange (ETDEWEB)

    Hunziker, R.; Meier, A.; Jacoby, P. [ABB Turbo Systems, Baden (Switzerland)

    2002-06-01

    A new turbocharger series TPS.-F33 has been developed by ABB to fulfil the current and future requirements of small medium-speed and large high speed diesel engines as well as gas engines, all ranging from 500 kW to 3500 kW output power. The development was focused on increasing pressure ratio and increasing flow capacity while ensuring high efficiency, reliability, long lifetime, and ease of maintenance. This new series - with the same outline dimensions as the current TPS.D/E turbochargers - is comprised of four different turbocharger sizes and allows for a substantial performance increase. (orig.) [German] ABB hat die neue TPS..-F33-Turboladerbaureihe entwickelt, um die heutigen und zukuenftigen Anforderungen von kleinen mittelschnell laufenden Dieselmotoren und grossen schnell laufenden Diesel- und Gasmotoren im Leistungsbereich von 500 bis 3500 kW zu erfuellen. Die Entwicklung zielte auf hoehere Druckverhaeltnisse und Volumendurchsaetze bei hohen Wirkungsgraden, Zuverlaessigkeit, hoher Lebensdauer und Wartungsfreundlichkeit. Die TPS..-F33-Baureihe - mit denselben aeusseren Dimensionen wie die TPS..D/E-Turbolader - umfasst vier Turboladergroessen mit einer hoeheren Leistungsdichte und erlaubt eine betraechtliche Leistungssteigerung. Ein praemierter Bericht des CIMAC-Kongresses 2001. (orig.)

  1. Exchange Flow Rate Measurement Technique in Density Different Gases

    Directory of Open Access Journals (Sweden)

    Motoo Fumizawa

    2012-04-01

    Full Text Available Buoyancy-driven exchange flows of helium-air through inclined a narrow tube was investigated. Exchange flows may occur following the opening of a window for ventilation, as well as when a pipe ruptures in a high temperature gas-cooled reactor. The experiment in this paper was carried out in a test chamber filled with helium and the flow was visualized using the smoke wire method. A high-speed camera recorded the flow behavior. The image of the flow was transferred to digital data, and the slow flow velocity, i.e. micro flow rate was measured by PIV software. Numerical simulation was carried out by the code of moving particle method with Lagrange method.

  2. High rate CNP removal from a milk processing wastewater in a single ultrasound augmented up-flow anaerobic/aerobic/anoxic bioreactor.

    Science.gov (United States)

    Rezaee, S; Zinatizadeh, A A L; Asadi, A

    2015-03-01

    Simultaneous removal of carbon, nitrogen and phosphorus (CNP) in a single bioreactor is of high significance in terms of reactor volume and energy consumption. Therefore, in this study, an innovative up-flow anaerobic/aerobic/anoxic bioreactor (UAAASB) augmented by ultrasound was developed as a high rate single bioreactor for the simultaneous removal of nutrients from a milk processing wastewater. The ultrasonic irradiation used in this work was in the range of high frequency (1.7 MHz). The central composite design (CCD) and response surface methodology (RSM) were applied to design the experimental conditions, model obtained data, and optimize the process. The effects of three independent variables, i.e. hydraulic retention time (HRT), aeration mode and mixed liquor suspended solid (MLSS) concentration on 10 process responses were investigated. The results prove that the ultrasonic irradiation has a positive effect on the sludge settling velocity and effluent turbidity. The optimum conditions were determined as 12-15 h, 4000-5000 mg/l and 1.5-2 for HRT, MLSS concentration and aeration mode, respectively, based on removal efficiency of sCOD ⩾ 90%, TN and TP ⩾ 50%.

  3. Preparation of low flow-resistant methacrylate-based monolithic stationary phases of different hydrophobicity and the application to rapid reversed-phase liquid chromatographic separation of alkylbenzenes at high flow rate and elevated temperature.

    Science.gov (United States)

    Ueki, Yuji; Umemura, Tomonari; Iwashita, Yoshikazu; Odake, Tamao; Haraguchi, Hiroki; Tsunoda, Kin-ichi

    2006-02-17

    Low flow-resistant alkyl methacrylate-based monolithic stationary phases of different hydrophobicity were constructed for reversed-phase capillary liquid chromatography by thermally initiated radical polymerization of respective methacrylate ester monomer with different alkyl chain (C2, C4, C6, C12, C18) and ethylene glycol dimethacrylate (EDMA) in a 250 microm i.d. fused silica capillary. The hydrophobicity was basically controlled by changing the length and/or the density of the alkyl-chain, while the composition and the ratio of porogenic solvent were adjusted to obtain highly permeable rigid monoliths with adequate column efficiency. Among the prepared monolithic stationary phases, C18-methacrylate monoliths polymerized from a binary porogenic solvent of isoamyl alcohol and 1,4-buthandiol exhibited the most promising performance in terms of hydraulic resistance and column efficiency. The pressure drops of 20-cm long monolithic columns were below approximately 0.4 MPa at a normal linear velocity of 1mm/s (a flow rate of 3 microL/min), and the numbers of theoretical plates for alkylbenzenes mostly exceeded 3000 plates/20 cm. The produced monolithic columns had good mechanical strength for high pressure and temperature, and could be properly operated even at a temperature of 80 degrees C and at a pressure of at least 33 MPa. At 80 degrees C, the theoretical plate numbers reached 6000 plates/20 cm because of the enhanced mass transfer. Due to the novel hydraulic resistance and mechanical strength, the separation time could be reduced 120-fold simply by raising the flow rate and column temperature.

  4. High Repetition-Rate Neutron Generation by Several-mJ, 35 fs pulses interacting with Free-Flowing D2O

    Science.gov (United States)

    Hah, Jungmoo; Petrov, George; Nees, John; He, Zhaohan; Hammig, Mark; Krushelnick, Karl; Thomas, Alexander

    2016-10-01

    Recent advance in ultra-high power laser technology allows a development of laser-based neutron sources. Here we demonstrate heavy-water based neutron source. Using several-mJ energy pulses from a high-repetition rate (½kHz), ultrashort (35 fs) pulsed laser interacting with a 10 μm diameter stream of free-flowing heavy water (D2O), we get a 2.45 MeV neutron flux of 105/s. In the intentionally generated pre-plasma, laser pulse energy is efficiently absorbed, and energetic deuterons are generated. As a convertor, the bulk heavy water stream target and the large volume of low density D2O vapor near the target are collided with accelerated deuterons, generating neutron through d(d,n)3He reactions. As laser pulse energy increased from 6mJ to 12mJ, the neutron flux increased. From the 2D particle-in-cell simulation, comparable neutron fluxes are shown at the similar laser characteristics to the experiment. Also, simulation shows forward and backward moving deuterons, which are main distributing ions impinging upon D2O stream and vapor, respectively. This material is based upon work supported by the Air Force Office of Scien- tific Research under Award Numbers FA9550-12-1-0310 (Young Investigator Program) and FA9550-14-1-0282.

  5. Fabrication of cm scale buckypapers of horizontally aligned multiwalled carbon nanotubes highly filled with Fe3C: the key roles of Cl and Ar-flow rates.

    Science.gov (United States)

    Boi, Filippo S; Guo, Jian; Wang, Shanling; He, Yi; Xiang, Gang; Zhang, Xi; Baxendale, Mark

    2016-03-18

    A key challenge in the fabrication of ferromagnetically filled carbon-nanotube buckypapers in the presence of Cl-radicals is the achievement of a preferential horizontal nanotube-alignment. We show that a horizontal-alignment can be achieved by tuning two main CVD parameters for a fixed dichlorobenzene concentration: the precursor-evaporation temperature and the flow rate.

  6. High frame rate synthetic aperture duplex imaging

    DEFF Research Database (Denmark)

    Stuart, Matthias Bo; Tomov, Borislav Gueorguiev; Pihl, Michael Johannes

    2013-01-01

    aperture flow imaging as demonstrated in this paper. Synthetic aperture, directional beamforming, and cross-correlation are used to produce B-mode and vector velocity images at high frame rates. The frame rate equals the effective pulse repetition frequency of each imaging mode. Emissions for making the B...

  7. The Salivary IgA Flow Rate Is Increased by High Concentrations of Short-Chain Fatty Acids in the Cecum of Rats Ingesting Fructooligosaccharides

    Directory of Open Access Journals (Sweden)

    Yuko Yamamoto

    2016-08-01

    Full Text Available Salivary immunoglobulin A (IgA serves as a major effector in mucosal immunity by preventing submucosal invasion of pathogens. However, the mechanism by which consumption of fermentable fibers increases IgA in saliva was not fully elucidated. This study investigated the effects of fructooligosaccharides (FOS intake and time after feeding on IgA levels in the saliva and cecal digesta and on the concentration of short-chain fatty acids (SCFA in the cecum in rats. Five-week-old rats were fed a fiber-free diet or a diet with 50 g/kg FOS for zero, one, four, and eight weeks. Ingestion of FOS at one and eight weeks led to a higher IgA flow rate of saliva per weight of submandibular gland tissue (p < 0.05, which positively correlated with the concentration of SCFA in the cecal digesta (rs = 0.86, p = 0.0006, n = 12, but showed no correlation with the concentration of IgA in the cecal digesta (rs = 0.15, p = 0.3, n = 48. These results suggested that ingestion of FOS increased salivary IgA secretion through high levels of SCFA in the large intestine, which was produced by fermentation of FOS. Thus, continuously ingesting FOS for more than one week could increase secretion of salivary IgA.

  8. The Salivary IgA Flow Rate Is Increased by High Concentrations of Short-Chain Fatty Acids in the Cecum of Rats Ingesting Fructooligosaccharides.

    Science.gov (United States)

    Yamamoto, Yuko; Takahahi, Toru; To, Masahiro; Nakagawa, Yusuke; Hayashi, Takashi; Shimizu, Tomoko; Kamata, Yohei; Saruta, Juri; Tsukinoki, Keiichi

    2016-08-17

    Salivary immunoglobulin A (IgA) serves as a major effector in mucosal immunity by preventing submucosal invasion of pathogens. However, the mechanism by which consumption of fermentable fibers increases IgA in saliva was not fully elucidated. This study investigated the effects of fructooligosaccharides (FOS) intake and time after feeding on IgA levels in the saliva and cecal digesta and on the concentration of short-chain fatty acids (SCFA) in the cecum in rats. Five-week-old rats were fed a fiber-free diet or a diet with 50 g/kg FOS for zero, one, four, and eight weeks. Ingestion of FOS at one and eight weeks led to a higher IgA flow rate of saliva per weight of submandibular gland tissue (p IgA in the cecal digesta (rs = 0.15, p = 0.3, n = 48). These results suggested that ingestion of FOS increased salivary IgA secretion through high levels of SCFA in the large intestine, which was produced by fermentation of FOS. Thus, continuously ingesting FOS for more than one week could increase secretion of salivary IgA.

  9. Wall Shear Rates in Taylor Vortex Flow

    Directory of Open Access Journals (Sweden)

    V. Sobolik

    2011-01-01

    Full Text Available Wall shear rate and its axial and azimuthal components were evaluated in stable Taylor vortices. The measurements were carried out in a broad interval of Taylor numbers (52-725 and several gap width (R1/R2 = 0.5 – 0.8 by two three-segment electrodiffusion probes and three single probes flush mounted in the wall of the outer fixed cylinder. The axial distribution of wall shear rate components was obtained by sweeping the vortices along the probes using a slow axial flow. The experimental results were verified by CFD simulations. The knowledge of local wall shear rates and its fluctuations is of primordial interest for industrial applications like tangential filtration, membrane reactors and bioreactors containing shear sensitive cells.

  10. High rate drift chambers

    Energy Technology Data Exchange (ETDEWEB)

    Christian, D.C. (Fermilab, Batavia, IL 60510 (United States)); Berisso, M.C. (Fermilab, Batavia, IL 60510 (United States)); Gutierrez, G. (Fermilab, Batavia, IL 60510 (United States)); Holmes, S.D. (Fermilab, Batavia, IL 60510 (United States)); Wehmann, A. (Fermilab, Batavia, IL 60510 (United States)); Avilez, C. (Instituto de Fisica, Universidad de Guanajuato, Leon, Guanajuato (Mexico)); Felix, J. (Instituto de Fisica, Universidad de Guanajuato, Leon, Guanajuato (Mexico)); Moreno, G. (Instituto de Fisica, Universidad de Guanajuato, Leon, Guanajuato (Mexico)); Romero, M. (Instituto de Fisica, Universidad de Guanajuato, Leon, Guanajuato (Mexico)); Sosa, M. (Instituto de Fisica, Universidad de Guanajuato, Leon, Guanajuato (Mexico)); Forbush, M. (Department of Physics, Texas A and M University, College Station, TX 77843 (United States)); Huson, F.R. (Department of Physics, Texas A and M University, College Station, TX 77843 (United States)); Wightman, J.A. (Department of Physi

    1994-06-01

    Fermilab experiment 690, a study of target dissociation reactions pp[yields]pX using an 800 GeV/c proton beam and a liquid hydrogen target, collected data in late 1991. The incident beam and 600-800 GeV/c scattered protons were measured using a system of six 6 in.x4 in. and two 15 in.x8 in. pressurized drift chambers spaced over 260 m. These chambers provided precise measurements at rates above 10 MHz (2 MHz per cm of sense wire). The measurement resolution of the smaller chambers was 90 [mu]m, and the resolution of the larger chambers was 125 [mu]m. Construction details and performance results, including radiation damage, are presented. ((orig.))

  11. Increasing granular flow rate with obstructions

    Directory of Open Access Journals (Sweden)

    Alan Murray

    2016-03-01

    Full Text Available We describe a simple experiment involving spheres rolling down an inclined plane towards a bottleneck and through a gap. Results of the experiment indicate that flow rate can be increased by placing an obstruction at optimal positions near the bottleneck. We use the experiment to develop a computer simulation using the PhysX physics engine. Simulations confirm the experimental results and we state several considerations necessary to obtain a model that agrees well with experiment. We demonstrate that the model exhibits clogging, intermittent and continuous flow, and that it can be used as a tool for further investigations in granular flow. Received: 22 November 2015, Accepted: 19 February 2016; Edited by: L. A. Pugnaloni; Reviewed by: C. M. Carlevaro, Instituto de Física de Líquidos y Sistemas Biológicos, La Plata, Argentina; DOI: http://dx.doi.org/10.4279/PIP.080003 Cite as: A Murray, F Alonso-Marroquin, Papers in Physics 8, 080003 (2016

  12. Responses of prawn to water flow rates

    Energy Technology Data Exchange (ETDEWEB)

    Vascotto, G.L.; Nilas, P.U.

    1987-05-28

    An aquarium study to determine the responses of postlarval macrobrachium rosenbergii to varying water changes was carried out. Six week old postlarvae were raised in glass aquaria receiving 0, 1.15, 7.2 and 14.4 water changes per day over a 12 week period. The treatments had significant influences on survival, biomass, and average size of the animals. Maximum survival and highest biomass were found in the 1.15 water turnover treatment; however, this treatment also produced the smallest average size animals. Early high mortalities were attributed to poor growing conditions in the high and low flow treatments, while later mortality appeared to be biomass dependent.

  13. Relationship between salivary flow rates and Candida albicans counts.

    Science.gov (United States)

    Navazesh, M; Wood, G J; Brightman, V J

    1995-09-01

    Seventy-one persons (48 women, 23 men; mean age, 51.76 years) were evaluated for salivary flow rates and Candida albicans counts. Each person was seen on three different occasions. Samples of unstimulated whole, chewing-stimulated whole, acid-stimulated parotid, and candy-stimulated parotid saliva were collected under standardized conditions. An oral rinse was also obtained and evaluated for Candida albicans counts. Unstimulated and chewing-stimulated whole flow rates were negatively and significantly (p or = 500 count. Differences in stimulated parotid flow rates were not significant among different levels of Candida counts. The results of this study reveal that whole saliva is a better predictor than parotid saliva in identification of persons with high Candida albicans counts.

  14. High-Throughput Contact Flow Lithography.

    Science.gov (United States)

    Le Goff, Gaelle C; Lee, Jiseok; Gupta, Ankur; Hill, William Adam; Doyle, Patrick S

    2015-10-01

    High-throughput fabrication of graphically encoded hydrogel microparticles is achieved by combining flow contact lithography in a multichannel microfluidic device and a high capacity 25 mm LED UV source. Production rates of chemically homogeneous particles are improved by two orders of magnitude. Additionally, the custom-built contact lithography instrument provides an affordable solution for patterning complex microstructures on surfaces.

  15. Process Measurement Deviation Analysis for Flow Rate due to Miscalibration

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Eunsuk; Kim, Byung Rae; Jeong, Seog Hwan; Choi, Ji Hye; Shin, Yong Chul; Yun, Jae Hee [KEPCO Engineering and Construction Co., Deajeon (Korea, Republic of)

    2016-10-15

    An analysis was initiated to identify the root cause, and the exemption of high static line pressure correction to differential pressure (DP) transmitters was one of the major deviation factors. Also the miscalibrated DP transmitter range was identified as another major deviation factor. This paper presents considerations to be incorporated in the process flow measurement instrumentation calibration and the analysis results identified that the DP flow transmitter electrical output decreased by 3%. Thereafter, flow rate indication decreased by 1.9% resulting from the high static line pressure correction exemption and measurement range miscalibration. After re-calibration, the flow rate indication increased by 1.9%, which is consistent with the analysis result. This paper presents the brief calibration procedures for Rosemount DP flow transmitter, and analyzes possible three cases of measurement deviation including error and cause. Generally, the DP transmitter is required to be calibrated with precise process input range according to the calibration procedure provided for specific DP transmitter. Especially, in case of the DP transmitter installed in high static line pressure, it is important to correct the high static line pressure effect to avoid the inherent systematic error for Rosemount DP transmitter. Otherwise, failure to notice the correction may lead to indicating deviation from actual value.

  16. Life history and past demography maintain genetic structure, outcrossing rate, contemporary pollen gene flow of an understory herb in a highly fragmented rainforest

    Directory of Open Access Journals (Sweden)

    Pilar Suárez-Montes

    2016-12-01

    Full Text Available Introduction Theory predicts that habitat fragmentation, by reducing population size and increasing isolation among remnant populations, can alter their genetic diversity and structure. A cascade of effects is expected: genetic drift and inbreeding after a population bottleneck, changes in biotic interactions that may affect, as in the case of plants, pollen dynamics, mating system, reproductive success. The detection of the effects of contemporary habitat fragmentation on the genetic structure of populations are conditioned by the magnitude of change, given the few number of generations since the onset of fragmentation, especially for long-lived organisms. However, the present-day genetic structure of populations may bear the signature of past demography events. Here, we examine the effects of rainforest fragmentation on the genetic diversity, population structure, mating system (outcrossing rate, indirect gene flow and contemporary pollen dynamics in the understory herb Aphelandra aurantiaca. Also, we assessed its present-day genetic structure under different past demographic scenarios. Methods Twelve populations of A. aurantiaca were sampled in large (4, medium (3, and small (5 forest fragments in the lowland tropical rainforest at Los Tuxtlas region. Variation at 11 microsatellite loci was assessed in 28–30 reproductive plants per population. In two medium- and two large-size fragments we estimated the density of reproductive plants, and the mating system by analyzing the progeny of different mother plants per population. Results Despite prevailing habitat fragmentation, populations of A. aurantiaca possess high genetic variation (He = 0.61, weak genetic structure (Rst = 0.037, and slight inbreeding in small fragments. Effective population sizes (Ne were large, but slightly lower in small fragments. Migrants derive mostly from large and medium size fragments. Gene dispersal is highly restricted but long distance gene dispersal events

  17. Understanding High Saving Rate in China

    Institute of Scientific and Technical Information of China (English)

    Xinhua He; Yongfu Cao

    2007-01-01

    This paper presents a detailed analysis of the Chinese saving rate based on the flow of funds data. It finds that the most widely adopted view of precautionary saving, which is regarded as the top reason for maintaining a high saving rate in China, is misleading because this conclusion is drawn from the household survey data. In fact, the household saving rate has declined dramatically since the mid-1990s, as is observed from the flow of funds framework.The high national saving rate is attributed to the increasing shares of both government and corporation disposable incomes. Insufficient consumption demand is caused by the persistent decrease in percentage share of household to national disposable income. Governmentdirected income redistribution urgently needs to be improved to accelerate consumption,which in turn would make the Chinese economy less investment-led and help to reduce the current account surplus.

  18. Effects of argon gas flow rate on laser-welding.

    Science.gov (United States)

    Takayama, Yasuko; Nomoto, Rie; Nakajima, Hiroyuki; Ohkubo, Chikahiro

    2012-01-01

    The purpose of this study was to evaluate the effects of the rate of argon gas flow on joint strength in the laser-welding of cast metal plates and to measure the porosity. Two cast plates (Ti and Co-Cr alloy) of the same metal were abutted and welded together. The rates of argon gas flow were 0, 5 and 10 L/min for the Co-Cr alloy, and 5 and 10 L/min for the Ti. There was a significant difference in the ratio of porosity according to the rate of argon gas flow in the welded area. Argon shielding had no significant effect on the tensile strength of Co-Cr alloy. The 5 L/min specimens showed greater tensile strength than the 10 L/min specimens for Ti. Laser welding of the Co-Cr alloy was influenced very little by argon shielding. When the rate of argon gas flow was high, joint strength decreased for Ti.

  19. Construction of the flow rate nomogram using polynomial regression.

    Science.gov (United States)

    Hosmane, B; Maurath, C; McConnell, M

    1993-04-01

    The urinary flow rates of normal individuals depend on the initial bladder volume in a non-linear fashion (J. Urol. 109 (1973) 874). A flow rate nomogram was developed by Siroky, Olsson and Krane, (J. Vol. 122 (1979) 665), taking the non-linear relationship into account, as an aid in the interpretation of urinary flow rate data. The use of a flow rate nomogram is to differentiate normal from obstructed individuals and is useful in the post operative follow-up of urinary outflow obstruction. It has been shown (J. Urol. 123 (1980) 123) that the flow rate nomogram is an objective measure of the efficacy of medical or surgical therapy. Instead of manually reading nomogram values from the flow rate nomogram, an algorithm is developed using polynomial regression to fit the flow rate nomograms and hence compute nomogram values directly from the fitted nomogram equations.

  20. Droplet entrainment rate in gas-liquid annular flow

    Energy Technology Data Exchange (ETDEWEB)

    Sawant, P. [Energy Research Inc., Rockville, Maryland (United States); Liu, Y.; Ishii, M. [Purdue Univ., West Lafayette, Indiana (United States); Mori, M. [Tokyo Electric Power Co., Inc., Yokohama (Japan); Chen, S. [Purdue Univ., West Lafayette, Indiana (United States)

    2011-07-01

    Droplet entrainment and deposition are the two most important physical phenomena in the gas-liquid annular two-phase flow. Modeling of these phenomena is essential for the estimation of dryout margins in the Light Water Reactors (LWRs) and the boilers. In this study, gas-liquid annular two-phase flow experiments are performed in a vertical round tube test section under adiabatic conditions. Air-water and organic fluid Freon-113 are used as the test fluids. The experiments covered a wide range of pressure and flow conditions. Liquid film extraction technique was used for the measurement of droplet entrainment and deposition rates. Additionally, the thickness of liquid film was measured in the air-water experiments using the ring type conductance probes. In this paper, the experimental data on entrainment rate is used to analyze the currently available correlations in the literature. The analysis showed that the existing correlations failed to predict the data at high gas velocity conditions. At high gas velocity, the experimental entrainment rate approaches a maximum limiting value; however, the correlations predicted continuously increasing entrainment rate as the gas velocity increases. (author)

  1. Effect of Flow Characteristics in the Downstream of Butterfly Valve on the Flow Rate Measurement using Venturi Tube

    Science.gov (United States)

    Yoon, Seok Ho; Lee, Jungho; Yu, Cheong Hwan; Park, San-Jin; Chung, Chang-Hwan

    2010-06-01

    For testing large-capacity pump, the accurate flow rate measurement is needed in the test loop. As a measuring method of flow rate, venturi tube is recommended due to its low pressure loss. However, upstream disturbance of loop component such as valve has an effect upon the accuracy of flow rate measurement. For controlling flow rate in case of high flow rate and large-scale piping system, butterfly-type valve is generally used due to its compactness. However, butterfly valve disturbs downstream flow by generating turbulence, cavities, or abrupt pressure change. In this study, the effect of downstream disturbance of butterfly valve on the flow rate measurement using venturi tube is investigated. Test loop consists of circulation pump, reservoir, butterfly valve, venturi tube, and reference flow meter. The test is conducted with regard to a different valve opening angle of butterfly valve. PIV system is used to visualize and analyze flow in the downstream region of butterfly valve. According to valve opening angle, the flow characteristics and the accuracy of flow rate measurement are investigated.

  2. Thrombus Formation at High Shear Rates.

    Science.gov (United States)

    Casa, Lauren D C; Ku, David N

    2017-06-21

    The final common pathway in myocardial infarction and ischemic stroke is occlusion of blood flow from a thrombus forming under high shear rates in arteries. A high-shear thrombus forms rapidly and is distinct from the slow formation of coagulation that occurs in stagnant blood. Thrombosis at high shear rates depends primarily on the long protein von Willebrand factor (vWF) and platelets, with hemodynamics playing an important role in each stage of thrombus formation, including vWF binding, platelet adhesion, platelet activation, and rapid thrombus growth. The prediction of high-shear thrombosis is a major area of biofluid mechanics in which point-of-care testing and computational modeling are promising future directions for clinically relevant research. Further research in this area will enable identification of patients at high risk for arterial thrombosis, improve prevention and treatment based on shear-dependent biological mechanisms, and improve blood-contacting device design to reduce thrombosis risk.

  3. Fisetin-Rich Extracts of Rhus verniciflua Stokes Improve Blood Flow Rates in Mice Fed Both Normal and High-Fat Diets.

    Science.gov (United States)

    Im, Won Kyun; Park, Hyun Jung; Lee, Kwang Soo; Lee, Jung Hoon; Kim, Young Dong; Kim, Kyeong-Hee; Park, Sang-Jae; Hong, Seokmann; Jeon, Sung Ho

    2016-02-01

    Although it has been previously reported that Rhus verniciflua Stokes (RVS) possesses in vitro anti-inflammatory activity, the precise in vivo mechanisms of RVS extracts and a main active component called fisetin have not been well elucidated. In this study, using newly developed protocols, we prepared urushiol-free but fisetin-enriched RVS extracts and investigated their effects on the vascular immune system. We found that the water-soluble fractions of detoxified RVS with the flavonoid fisetin can inhibit lipopolysaccharide-induced production of nitric oxide (NO) and prostaglandin E2 (PGE2). Furthermore, RVS can reduce inducible nitric oxide synthase and COX2 gene expression levels, which are responsible for NO and PGE2 production, respectively, in RAW264.7 macrophage cells. Because inflammation is linked to the activation of the coagulation system, we hypothesized that RVS and its active component fisetin possess anticoagulatory activities. As expected, we found that both RVS and fisetin could inhibit the coagulation of human peripheral blood cells. Moreover, in vivo RVS treatment could return the retarded blood flow elicited by a high-fat diet (HFD) back to the normal level in mice. In addition, RVS treatment has significantly reduced body weight gained by HFD in mice. Taken together, the fisetin-rich RVS extracts have potential antiplatelet and antiobesity activities and could be used as a functional food ingredient to improve blood circulation.

  4. Study of low resistivity and high work function ITO films prepared by oxygen flow rates and N2O plasma treatment for amorphous/crystalline silicon heterojunction solar cells.

    Science.gov (United States)

    Hussain, Shahzada Qamar; Oh, Woong-Kyo; Kim, Sunbo; Ahn, Shihyun; Le, Anh Huy Tuan; Park, Hyeongsik; Lee, Youngseok; Dao, Vinh Ai; Velumani, S; Yi, Junsin

    2014-12-01

    Pulsed DC magnetron sputtered indium tin oxide (ITO) films deposited on glass substrates with lowest resistivity of 2.62 x 10(-4) Ω x cm and high transmittance of about 89% in the visible wavelength region. We report the enhancement of ITO work function (Φ(ITO)) by the variation of oxygen (O2) flow rate and N2O surface plasma treatment. The Φ(ITO) increased from 4.43 to 4.56 eV with the increase in O2 flow rate from 0 to 4 sccm while surface treatment of N2O plasma further enhanced the ITO work function to 4.65 eV. The crystallinity of the ITO films improved with increasing O2 flow rate, as revealed by XRD analysis. The ITO work function was increased by the interfacial dipole resulting from the surface rich in O- ions and by the dipole moment formed at the ITO surface during N2O plasma treatment. The ITO films with high work functions can be used to modify the front barrier height in heterojunction with intrinsic thin layer (HIT) solar cells.

  5. A novel concept of measuring mass flow rates using flow induced stresses

    Indian Academy of Sciences (India)

    P I Jagad; B P Puranik; A W Date

    2015-08-01

    Measurement of mass flow rate is important for automatic control of the mass flow rate in many industries such as semiconductor manufacturing and chemical industry (for supply of catalyst to a reaction). In the present work, a new concept for direct measurement of mass flow rates which does not depend on the volumetric flow rate measurement and obviates the need for the knowledge of density is proposed from the measurement of the flow induced stresses in a substrate. The concept is formulated by establishing the relationship between the mass flow rate and the stress in the substrate. To this end, the flow field and the stress field in the substrate are evaluated simultaneously using a numerical procedure and the necessary correlations are derived. A least squares based procedure is used to derive the mass flow rate from the correlations as a function of the stress in the substrate.

  6. Measuring Flow Rate in Crystalline Bedrock Wells Using the Dissolved Oxygen Alteration Method.

    Science.gov (United States)

    Vitale, Sarah A; Robbins, Gary A

    2017-03-22

    Determination of vertical flow rates in a fractured bedrock well can aid in planning and implementing hydraulic tests, water quality sampling, and improving interpretations of water quality data. Although flowmeters are highly accurate in flow rate measurement, the high cost and logistics may be limiting. In this study the dissolved oxygen alteration method (DOAM) is expanded upon as a low-cost alternative to determine vertical flow rates in crystalline bedrock wells. The method entails altering the dissolved oxygen content in the wellbore through bubbler aeration, and monitoring the vertical advective movement of the dissolved oxygen over time. Measurements were taken for upward and downward flows, and under ambient and pumping conditions. Vertical flow rates from 0.06 to 2.30 Lpm were measured. To validate the method, flow rates determined with the DOAM were compared to pump discharge rates and found to be in agreement within 2.5%.

  7. Continuum modeling of rate-dependent granular flows in SPH

    Science.gov (United States)

    Hurley, Ryan C.; Andrade, José E.

    2016-09-01

    We discuss a constitutive law for modeling rate-dependent granular flows that has been implemented in smoothed particle hydrodynamics (SPH). We model granular materials using a viscoplastic constitutive law that produces a Drucker-Prager-like yield condition in the limit of vanishing flow. A friction law for non-steady flows, incorporating rate-dependence and dilation, is derived and implemented within the constitutive law. We compare our SPH simulations with experimental data, demonstrating that they can capture both steady and non-steady dynamic flow behavior, notably including transient column collapse profiles. This technique may therefore be attractive for modeling the time-dependent evolution of natural and industrial flows.

  8. Continuum modeling of rate-dependent granular flows in SPH

    Science.gov (United States)

    Hurley, Ryan C.; Andrade, José E.

    2017-01-01

    We discuss a constitutive law for modeling rate-dependent granular flows that has been implemented in smoothed particle hydrodynamics (SPH). We model granular materials using a viscoplastic constitutive law that produces a Drucker-Prager-like yield condition in the limit of vanishing flow. A friction law for non-steady flows, incorporating rate-dependence and dilation, is derived and implemented within the constitutive law. We compare our SPH simulations with experimental data, demonstrating that they can capture both steady and non-steady dynamic flow behavior, notably including transient column collapse profiles. This technique may therefore be attractive for modeling the time-dependent evolution of natural and industrial flows.

  9. High Data Rate Quantum Cryptography

    Science.gov (United States)

    Kwiat, Paul; Christensen, Bradley; McCusker, Kevin; Kumor, Daniel; Gauthier, Daniel

    2015-05-01

    While quantum key distribution (QKD) systems are now commercially available, the data rate is a limiting factor for some desired applications (e.g., secure video transmission). Most QKD systems receive at most a single random bit per detection event, causing the data rate to be limited by the saturation of the single-photon detectors. Recent experiments have begun to explore using larger degree of freedoms, i.e., temporal or spatial qubits, to optimize the data rate. Here, we continue this exploration using entanglement in multiple degrees of freedom. That is, we use simultaneous temporal and polarization entanglement to reach up to 8.3 bits of randomness per coincident detection. Due to current technology, we are unable to fully secure the temporal degree of freedom against all possible future attacks; however, by assuming a technologically-limited eavesdropper, we are able to obtain 23.4 MB/s secure key rate across an optical table, after error reconciliation and privacy amplification. In this talk, we will describe our high-rate QKD experiment, with a short discussion on our work towards extending this system to ship-to-ship and ship-to-shore communication, aiming to secure the temporal degree of freedom and to implement a 30-km free-space link over a marine environment.

  10. GROWTH RATE DISTRIBUTION OF BORAX SINGLE CRYSTALS ON THE (001 FACE UNDER VARIOUS FLOW RATES

    Directory of Open Access Journals (Sweden)

    Suharso Suharso

    2010-06-01

    Full Text Available The growth rates of borax single crystals from aqueous solutions at various flow rates in the (001 direction were measured using in situ cell method. From the growth rate data obtained, the growth rate distribution of borax crystals was investigated using Minitab Software and SPSS Software at relative supersaturation of 0807 and temperature of 25 °C. The result shows that normal, gamma, and log-normal distribution give a reasonably good fit to GRD. However, there is no correlation between growth rate distribution and flow rate of solution.   Keywords: growth rate dispersion (GRD, borax, flow rate

  11. Effect of flow rate on diameter of electrospun nanoporous fibers

    Directory of Open Access Journals (Sweden)

    Tang Xiao-Peng

    2014-01-01

    Full Text Available The effect of flow rate on the diameter of the charged jet in the electrospinning process is studied theoretically. The obtained theoretical results offer in-depth physical understanding and mechanism of nanoporous fibers. It also reveals that the morphology and diameter of nanoporous microspheres can be controlled by the flow rate.

  12. 14 CFR 23.1095 - Carburetor deicing fluid flow rate.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Carburetor deicing fluid flow rate. 23.1095 Section 23.1095 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Induction System § 23.1095 Carburetor deicing fluid flow rate. (a) If a carburetor deicing fluid system...

  13. A high-strain-rate superplastic ceramic.

    Science.gov (United States)

    Kim, B N; Hiraga, K; Morita, K; Sakka, Y

    2001-09-20

    High-strain-rate superplasticity describes the ability of a material to sustain large plastic deformation in tension at high strain rates of the order of 10-2 to 10-1 s-1 and is of great technological interest for the shape-forming of engineering materials. High-strain-rate superplasticity has been observed in aluminium-based and magnesium-based alloys. But for ceramic materials, superplastic deformation has been restricted to low strain rates of the order of 10-5 to 10-4 s-1 for most oxides and nitrides with the presence of intergranular cavities leading to premature failure. Here we show that a composite ceramic material consisting of tetragonal zirconium oxide, magnesium aluminate spinel and alpha-alumina phases exhibits superplasticity at strain rates up to 1 s-1. The composite also exhibits a large tensile elongation, exceeding 1,050 per cent for a strain rate of 0.4 s-1. The tensile flow behaviour and deformed microstructure of the material indicate that superplasticity is due to a combination of limited grain growth in the constitutive phases and the intervention of dislocation-induced plasticity in the zirconium oxide phase. We suggest that the present results hold promise for the application of shape-forming technologies to ceramic materials.

  14. Electrorheological Effects at High Shear Rate

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Much attention has been given to electrorheological (ER) fluids because of the ER effect, which has been described by a large number of researchers as a notable increase in the apparent viscosity of a fluid upon the application of an electric field. The description of ER effects is, however, not accurate at high shear rates. To clarify the discrepancy, we analyze and compute the apparent viscosity as a function of shear rate for ER fluid flow between rotating coaxial cylinders in the presence of an electric field. The theoretical predictions show that the increase of electric intensity contributes little to the apparent viscosity enhancement at high shear rates, while ER effects for ER fluids with a higher polarization rate still exist and ER devices possess controllability in this regime. Description of the ER effect by the apparent viscosity leads to an unrealistic conclusion that ER effects disappear at high shear rates, because the apparent viscosity of ER fluids approaches the value for Newtonian fluids. Therefore, it is concluded that the proper description of ER effects, i.e., one that holds uniformly for any strain rate when ER effects exist, is manifested by a remarkable increase in the extra stress rather than in the apparent viscosity of ER fluids.

  15. Impact Strength and Flow Melt Flow Rate of High Density Polyethylene Melts%高密度聚乙烯共混物的抗冲击强度与熔体流动速率

    Institute of Scientific and Technical Information of China (English)

    廖华勇; 陶国良

    2013-01-01

    Four high density polyethylene blends (HDPE 8916/5000S,HDPE 9641/5000S,HDPE 5306/5000S and HDPE 8916/6003T) were prepared.The notch impact strength σin and melt flow rate(MFR) were measured,and their relation was investigated.The results show that the notch impact strength σin drops with the increase of MFR,the σin-MFR curve meets the law of exponential decay.The area of σin-MFR curve surrounded by coordinate axes is the highest for HDPE 5306/HDPE5000S blend,which suggests it is the easiest for HDPE 5306/HDPE5000S blend to meet the notch impact strength and MFR requirement.Then HDPE 5306/HDPE5000S blend was toughened by adding polyolefin elastomer (POE).The results show when the mass ratio of HDPE 5306/ HDPE5000S/POE is 28.5/66.5/5,the notch impact strength σin arrives 42.88 kJ/m2 and the MFR is 2.64 g/10min (230℃,2.16kg),much higher than of HDPE 5306/HDPE5000S (30/70,mass ratio,similarly hereinafter),28.16 kJ/m2 and 2.55 g/10min(230℃,2.16kg),respectively.%制备了4种高密度聚乙烯(HDPE) HDPE 8916/5000S、HDPE 9641/5000S、HDPE 5306/5000S和HDPE 8916/6003T共混物,并测试其缺口冲击强度σin和熔体流动速率(MFR),探讨了两者之间的关系.结果表明,随着MFR的增加,缺口冲击强度逐渐下降,两者之间符合指数衰减规律.而其中HDPE 5306/HDPE5000S的σin-MFR曲线与坐标轴之间包围的面积最大,比其它3种共混物更容易实现同时满足冲击强度和流动性的要求.文中还对HDPE 5306/HDPE5000S共混物用乙烯-辛烯共高聚物(POE)进行增韧改性.结果表明,当HDPE 5306/HDPE5000S/POE的质量比为28.5/66.5/5时,缺口冲击强度达到42.88kJ/m2,高于HDPE 5306/HDPE5000S(30/70,质量比,下同)时的28.16kJ/m2,而POE增韧后共混物的MFR为2.64 g/10min(230℃,2.16kg),比HDPE 5306/HDPE5000S(30/70)时的MFR值2.55g/10min(230℃,2.16kg)高.

  16. Influence of total gas flow rate on microcrystalline silicon films prepared by VHF-PECVD

    Institute of Scientific and Technical Information of China (English)

    Gao Yan-Tao; Zhang Xiao-Dan; Zhao Ying; Sun Jian; Zhu Feng; Wei Chang-Chun; Chen Fei

    2006-01-01

    Hydrogenated microcrystalline silicon (μc-Si:H) films are fabricated by very high frequency plasma enhanced chemical vapour deposition (VHF-PECVD) at a silane concentration of 7% and a varying total gas flow rate (H2+SiH4).Relations between the total gas flow rate and the electrical and structural properties as well as deposition rate of the films are studied. The results indicate that with the total gas flow rate increasing the photosensitivity and deposition rate increase, but the crystalline volume fraction (Xc) and dark conductivity decrease. And the intensity of (220) peak first increases then decreases with the increase of the total gas flow rate. The cause for the changes in the structure and deposition rate of the films with the total gas flow rate is investigated using optical emission spectroscopy (OES).

  17. COMPUTATIONAL FLOW RATE FEEDBACK AND CONTROL METHOD IN HYDRAULIC ELEVATORS

    Institute of Scientific and Technical Information of China (English)

    Xu Bing; Ma Jien; Lin Jianjie

    2005-01-01

    The computational flow rate feedback and control method, which can be used in proportional valve controlled hydraulic elevators, is discussed and analyzed. In a hydraulic elevator with this method, microprocessor receives pressure information from the pressure transducers and computes the flow rate through the proportional valve based on pressure-flow conversion real time algorithm. This hydraulic elevator is of lower cost and energy consumption than the conventional closed loop control hydraulic elevator whose flow rate is measured by a flow meter. Experiments are carried out on a test rig which could simulate the load of hydraulic elevator. According to the experiment results, the means to modify the pressure-flow conversion algorithm are pointed out.

  18. 4D ultrafast ultrasound flow imaging: in vivo quantification of arterial volumetric flow rate in a single heartbeat

    Science.gov (United States)

    Correia, Mafalda; Provost, Jean; Tanter, Mickael; Pernot, Mathieu

    2016-12-01

    We present herein 4D ultrafast ultrasound flow imaging, a novel ultrasound-based volumetric imaging technique for the quantitative mapping of blood flow. Complete volumetric blood flow distribution imaging was achieved through 2D tilted plane-wave insonification, 2D multi-angle cross-beam beamforming, and 3D vector Doppler velocity components estimation by least-squares fitting. 4D ultrafast ultrasound flow imaging was performed in large volumetric fields of view at very high volume rate (>4000 volumes s-1) using a 1024-channel 4D ultrafast ultrasound scanner and a 2D matrix-array transducer. The precision of the technique was evaluated in vitro by using 3D velocity vector maps to estimate volumetric flow rates in a vessel phantom. Volumetric Flow rate errors of less than 5% were found when volumetric flow rates and peak velocities were respectively less than 360 ml min-1 and 100 cm s-1. The average volumetric flow rate error increased to 18.3% when volumetric flow rates and peak velocities were up to 490 ml min-1 and 1.3 m s-1, respectively. The in vivo feasibility of the technique was shown in the carotid arteries of two healthy volunteers. The 3D blood flow velocity distribution was assessed during one cardiac cycle in a full volume and it was used to quantify volumetric flow rates (375  ±  57 ml min-1 and 275  ±  43 ml min-1). Finally, the formation of 3D vortices at the carotid artery bifurcation was imaged at high volume rates.

  19. Characterization of Absorbent Flow Rate in Towel and Tissue

    Directory of Open Access Journals (Sweden)

    Paul D. Beuther

    2010-06-01

    Full Text Available The quality of a paper towel is often judged based on how quickly it can wipe up a spill. However, the test methods currently available cannot repeatably measure significant differences in absorbent rate between samples. Recent round-robin testing evaluations by TAPPI and CEN organizations have shown that past methods, such as ASTM D5802-95 and TAPPI T561-pm [1], are unreliable due to high variability. The reasons for the lack of repeatability are unclear. The relation between the wicking mechanism and the fundamental absorbent properties needs to be better understood. This paper uses x-ray imaging to show the overall flow characteristics of fluid absorption within a towel, and compares the results to model predictions to show which parameters are important to the process. From this understanding, a revised test method is proposed that provides adequate statistical discernment of absorbent rate properties of tissue on a simple lab-bench scale device.

  20. Implementation of an Associative Flow Rule Including Hydrostatic Stress Effects Into the High Strain Rate Deformation Analysis of Polymer Matrix Composites

    Science.gov (United States)

    Goldberg, Robert K.; Roberts, Gary D.; Gilat, Amos

    2003-01-01

    A previously developed analytical formulation has been modified in order to more accurately account for the effects of hydrostatic stresses on the nonlinear, strain rate dependent deformation of polymer matrix composites. State variable constitutive equations originally developed for metals have been modified in order to model the nonlinear, strain rate dependent deformation of polymeric materials. To account for the effects of hydrostatic stresses, which are significant in polymers, the classical J2 plasticity theory definitions of effective stress and effective inelastic strain, along with the equations used to compute the components of the inelastic strain rate tensor, are appropriately modified. To verify the revised formulation, the shear and tensile deformation of two representative polymers are computed across a wide range of strain rates. Results computed using the developed constitutive equations correlate well with experimental data. The polymer constitutive equations are implemented within a strength of materials based micromechanics method to predict the nonlinear, strain rate dependent deformation of polymer matrix composites. The composite mechanics are verified by analyzing the deformation of a representative polymer matrix composite for several fiber orientation angles across a variety of strain rates. The computed values compare well to experimentally obtained results.

  1. Analytically computed rates of seepage flow into drains and cavities

    Science.gov (United States)

    Fujii, N.; Kacimov, A. R.

    1998-04-01

    The known formulae of Freeze and Cherry, Polubarinova-Kochina, Vedernikov for flow rate during 2-D seepage into horizontal drains and axisymmetric flow into cavities are examined and generalized. The case of an empty drain under ponded soil surface is studied and existence of drain depth providing minimal seepage rate is presented. The depth is found exhibiting maximal difference in rate between a filled and an empty drain. 3-D flow to an empty semi-spherical cavity on an impervious bottom is analysed and the difference in rate as compared with a completely filled cavity is established. Rate values for slot drains in a two-layer aquifer are inverted using the Schulgasser theorem from the Polubarinova-Kochina expressions for corresponding flow rates under a dam. Flow to a point sink modelling a semi-circular drain in a layered aquifer is treated by the Fourier transform method. For unsaturated flow the catchment area of a single drain is established in terms of the quasi-linear model assuming the isobaric boundary condition along the drain contour. Optimal shape design problems for irrigation cavities are addressed in the class of arbitrary contours with seepage rate as a criterion and cavity cross-sectional area as an isoperimetric restriction.

  2. Design and Implementation of Automatic Air Flow Rate Control System

    Science.gov (United States)

    Akbar, A.; Saputra, C.; Munir, M. M.; Khairurrijal

    2016-08-01

    Venturimeter is an apparatus that can be used to measure the air flow rate. In this experiment we designed a venturimeter which equipped with a valve that is used to control the air flow rate. The difference of pressure between the cross sections was measured with the differential pressure sensor GA 100-015WD which can calculate the difference of pressures from 0 to 3737.33 Pa. A 42M048C Z36 stepper motor was used to control the valve. The precision of this motor rotation is about 0.15 °. A Graphical User Interface (GUI) was developed to monitor and set the value of flow rate then an 8-bit microcontroller was used to process the control system In this experiment- the venturimeter has been examined to get the optimal parameter of controller. The results show that the controller can set the stable output air flow rate.

  3. High flow nasal cannula for respiratory support in preterm infants.

    LENUS (Irish Health Repository)

    Wilkinson, Dominic

    2011-01-01

    High flow nasal cannulae (HFNC) are small, thin, tapered cannulae used to deliver oxygen or blended oxygen and air at flow rates of > 1 L\\/min. HFNC can be used to provide high concentrations of oxygen and may deliver positive end-expiratory pressure.

  4. Blood flow rate measurements with indicator techniques revisited

    DEFF Research Database (Denmark)

    Sejrsen, Per; Bülow, Jens

    2009-01-01

    In view of the emerging role, disturbances in regional blood flow rate seem to play in the pathogenesis of the metabolic syndrome; we review the concepts of the classical indicator dilution and washout techniques used for determinations of regional blood flow rate. Prerequisites, assumptions......, necessary precautions for the application of these experimental techniques are emphasized. Special attention has been carried out to elucidate the consequence of a choice of indicators having a large distribution volume in the tissues....

  5. Circuit and interconnect design for high bit-rate applications

    NARCIS (Netherlands)

    Veenstra, H.

    2006-01-01

    This thesis presents circuit and interconnect design techniques and design flows that address the most difficult and ill-defined aspects of the design of ICs for high bit-rate applications. Bottlenecks in interconnect design, circuit design and on-chip signal distribution for high bit-rate applicati

  6. Influence of Gas Flow Rate on the Deposition Rate on Stainless Steel 202 Substrates

    Directory of Open Access Journals (Sweden)

    M.A. Chowdhury

    2012-12-01

    Full Text Available Solid thin films have been deposited on stainless steel 202 (SS 202 substrates at different flow rates of natural gas using a hot filament thermal chemical vapor deposition (CVD reactor. In the experiments, the variations of thin film deposition rate with the variation of gas flow rate have been investigated. The effects of gap between activation heater and substrate on the deposition rate have also been observed. Results show that deposition rate on SS 202 increases with the increase in gas flow rate within the observed range. It is also found that deposition rate increases with the decrease in gap between activation heater and substrate. In addition, friction coefficient and wear rate of SS 202 sliding against SS 304 under different sliding velocities are also investigated before and after deposition. The experimental results reveal that improved friction coefficient and wear rate is obtained after deposition than that of before deposition.

  7. Numerical study on flow rate limitation of open capillary channel flow through a wedge

    Directory of Open Access Journals (Sweden)

    Ting-Ting Zhang

    2016-04-01

    Full Text Available The flow characteristics of slender-column flow in wedge-shaped channel under microgravity condition are investigated in this work. The one-dimensional theoretical model is applied to predict the critical flow rate and surface contour of stable flow. However, the one-dimensional model overestimates the critical flow rate for not considering the extra pressure loss. Then, we develop a three-dimensional simulation method with OpenFOAM, a computational fluid dynamics tool, to simulate various phenomena in wedge channels with different lengths. The numerical results are verified with the capillary channel flow experimental data on the International Space Station. We find that the three-dimensional simulation perfectly predicts the critical flow rates and surface contours under various flow conditions. Meanwhile, the general behaviors in subcritical, critical, and supercritical flow are studied in three-dimensional simulation considering variations of flow rate and open channel length. The numerical techniques for three-dimensional simulation is validated for a wide range of configurations and is hopeful to provide valuable guidance for capillary channel flow experiment and efficient liquid management in space.

  8. The influence of the flow rate on periodic flow unsteadiness behaviors in a sewage centrifugal pump

    Institute of Scientific and Technical Information of China (English)

    裴吉; 袁寿其; 袁建平; 王文杰

    2013-01-01

    To design a single-blade pump with a good performance in a wide operational range and to increase the pump reliability in the multi-conditional hydraulic design process, an understanding of the unsteady flow behaviors as related with the flow rate is very important. However, the traditional design often considers only a single design condition, and the unsteady flow behaviors have not been well studied for single-blade pumps under different conditions. A comparison analysis of the flow unsteadiness behaviors at di-fferent flow rates within the whole flow passage of the pump is carried out in this paper by solving the three-dimensional unsteady Reynolds-averaged Navier-Stokes equations with the Shear Stress Transport (SST) turbulence model. A definition of the unsteadi-ness in the pump is made and applied to analyze the unsteady intensity distributions, and the flow rate effect on the complex unsteady flow in the pump is studied quantitatively while the flow mechanism is also analyzed. The CFD results are validated by experimental data collected at the laboratory. It is shown that a significant flow rate effect on the time-averaged unsteadiness and the turbulence in-tensity distribution can be observed in both rotor and stator domains including the side chamber. The findings would be useful to re-duce the flow unsteadiness and to increase the pump reliability under multi-conditions.

  9. Investigation of the Flow Rate Effect Upstream of the Constant-Geometry Throttle on the Gas Mass Flow

    Directory of Open Access Journals (Sweden)

    Yu. M. Timofeev

    2016-01-01

    Full Text Available The turbulent-flow throttles are used in pneumatic systems and gas-supply ones to restrict or measure gas mass flow. It is customary to install the throttles in joints of pipelines (in teejoints and cross tees or in joints of pipelines with pneumatic automation devices Presently, in designing the pneumatic systems and gas-supply ones a gas mass flow through a throttle is calculated by a known equation derived from the Saint-Venant-Vantсel formula for the adiabatic flow of ideal gas through a nozzle from an unrestrictedly high capacity tank. Neglect of gas velocity at the throttle inlet is one of the assumptions taken in the development of the above equation. As may be seen in practice, in actual systems the diameters of the throttle and the pipe wherein it is mounted can be commensurable. Neglect of the inlet velocity therewith can result in an error when determining the required throttle diameter in design calculation and a flow rate in checking calculation, as well as when measuring a flow rate in the course of the test. The theoretical study has revealed that the flow velocity at the throttle inlet is responsible for two parameter values: the outlet flow velocity and the critical pressure ratio, which in turn determine the gas mass flow value. To calculate the gas mass flow, the dependencies are given in the paper, which allow taking into account the flow rate at the throttle inlet. The analysis of obtained dependencies has revealed that the degree of influence of inlet flow rate upon the mass flow is defined by two parameters: pressure ratio at the throttle and open area ratio of the throttle and the pipe wherein it is mounted. An analytical investigation has been pursued to evaluate the extent to which the gas mass flow through the throttle is affected by the inlet flow rate. The findings of the investigation and the indications for using the present dependencies are given in this paper. By and large the investigation allowed the

  10. Highly deformable nanofilaments in flow

    Science.gov (United States)

    Pawłowska, S.

    2016-10-01

    Experimental analysis of hydrogel nanofilaments conveyed by flow is conducted to help in understanding physical phenomena responsible for transport properties and shape deformations of long bio-objects, like DNA or proteins. Investigated hydrogel nanofilaments exhibit typical macromolecules-like behavior, as spontaneous conformational changes and cross-flow migration. Results of the experiments indicate critical role of thermal fluctuations behavior of single filaments.

  11. VARIABLE FIRING RATE OIL BURNER USING PULSE FUEL FLOW CONTROL.

    Energy Technology Data Exchange (ETDEWEB)

    KRISHNA,C.R.; BUTCHER,T.A.; KAMATH,B.R.

    2004-10-01

    The residential oil burner market is currently dominated by the pressure-atomized retention head burner, which has an excellent reputation for reliability and efficiency. In this burner, oil is delivered to a fuel nozzle at pressures from 100 to 150 psi. In addition, to atomizing the fuel, the small, carefully controlled size of the nozzle exit orifice serves to control the burner firing rate. Burners of this type are currently available at firing rates of more than 0.5 gallons-per-hour (70,000 Btu/hr). Nozzles have been made for lower firing rates, but experience has shown that such nozzles suffer rapid fouling of the necessarily small passages, leading to bad spray patterns and poor combustion performance. Also, traditionally burners and the nozzles are oversized to exceed the maximum demand. Typically, this is figured as follows. The heating load of the house on the coldest day for the location is considered to define the maximum heat load. The contractor or installer adds to this to provide a safety margin and for future expansion of the house. If the unit is a boiler that provides domestic hot water through the use of a tankless heating coil, the burner capacity is further increased. On the contrary, for a majority of the time, the heating system is satisfying a much smaller load, as only rarely do all these demands add up. Consequently, the average output of the heating system has to be much less than the design capacity and this is accomplished by start and stop cycling operation of the system so that the time-averaged output equals the demand. However, this has been demonstrated to lead to overall efficiencies lower than the steady-state efficiency. Therefore, the two main reasons for the current practice of using oil burners much larger than necessary for space heating are the unavailability of reliable low firing rate oil burners and the desire to assure adequate input rate for short duration, high draw domestic hot water loads. One approach to solve this

  12. Long term low latitude and high elevation cosmogenic 3He production rate inferred from a 107 ka-old lava flow in northern Chile; 22°S-3400 m a.s.l.

    Science.gov (United States)

    Delunel, Romain; Blard, Pierre-Henri; Martin, Léo C. P.; Nomade, Sébastien; Schlunegger, Fritz

    2016-07-01

    Available geological calibration sites used to estimate the rate at which cosmogenic 3He is produced at the Earth's surface are mostly clustered in medium to high latitudes. Moreover, most of them have exposure histories shorter than tens of thousands of years. This lack of sites prevents a qualitative assessment of available production models used to convert cosmogenic 3He concentrations into exposure ages and/or denudation rates. It thus limits our ability to take into account the atmospheric, geomagnetic and solar modulation conditions that might have affected the production of cosmogenic nuclides in the past for longer exposure histories and in low latitude regions. We present the cosmogenic 3He production rate inferred from a new geological calibration site located in northern Chile. Five samples were collected on the surface of the largest and best-preserved lava flow of the San Pedro volcano (21.934°S-68.510°W-3390 m a.s.l.), which displays pristine crease-structure features. 40Ar/39Ar dating yields a reliable plateau age of 107 ± 12 ka for the eruption of this lava flow. Eight pyroxene aliquots separated from the surface samples yield a weighted average cosmogenic 3He concentration of 99.3 ± 1.2 Mat g-1 from which a local cosmogenic 3He production rate of 928 ± 101 at g-1 yr-1 is calculated. The local production rate is then scaled to a sea level high latitude (SLHL) reference position using different combinations of geographic spatialization schemes, atmosphere models and geomagnetic field reconstructions, yielding SLHL production rates between 103 ± 11 and 130 ± 14 at g-1 yr-1 consistent with the most recent estimates available from the literature. Finally, we use the same scaling frameworks to re-evaluate the mean global-scale cosmogenic 3He production rate in olivine and pyroxene minerals at 120 ± 16 at g-1 yr-1 from the compilation of previously published calibration datasets.

  13. Nocturnal variations in peripheral blood flow, systemic blood pressure, and heart rate in humans

    DEFF Research Database (Denmark)

    Sindrup, J H; Kastrup, J; Christensen, H

    1991-01-01

    was associated with a 30-40% increase in blood flow rate and a highly significant decrease in mean arterial blood pressure and heart rate (P less than 0.001 for all). Approximately 100 min after the subjects went to sleep an additional blood flow rate increment (mean 56%) and a simultaneous significant decrease......Subcutaneous adipose tissue blood flow rate, together with systemic arterial blood pressure and heart rate under ambulatory conditions, was measured in the lower legs of 15 normal human subjects for 12-20 h. The 133Xe-washout technique, portable CdTe(Cl) detectors, and a portable data storage unit...... were used for measurement of blood flow rates. An automatic portable blood pressure recorder and processor unit was used for measurement of systolic blood pressure, diastolic blood pressure, and heart rate every 15 min. The change from upright to supine position at the beginning of the night period...

  14. Flow of granular materials-I. Discharge rates from hoppers

    Energy Technology Data Exchange (ETDEWEB)

    Nedderman, R.M. (Univ. of Cambridge, England); Tuezuen, U.; Savage, S.B.; Houlsby, G.T.

    1982-01-01

    This was the first of a set of three review papers on the flow of granular materials. The objective of the papers was to review the published literature in these fields. Much information was drawn from a body of unpulished work represented by internal reports of the Chemical Engineering Department at Cambridge. This paper discussed the experimental results for hopper discharge rates and the correlations of these results. Then theoretical analyses that have been advanced to explain the observations were presented. Also the effects of interstitial pressure gradients were discussed, both those that arise due to deliberate pressurization of the hopper and those caused by the dilation of the flowing material. The flow of coarse, free-flowing materials through orifices seemed to have been adequately investigated experimentally and the correlation of Beverloo or minor modifications of it appeared to predict the flow rates with acceptable precision. Some difficulties were however encountered with narrow angled conical hoppers or in cases where the orifice is close to a vertical wall. The effects of an imposed gas flow were also correlated to reasonable precision at least for modest gas flow rates. Though the correlations seemed satisfactory, there was no really adequate theoretical explanations of the observations. Several theories exist that give qualitative trends in accord with obsrvation but there is no theory that can be used without empirical adjustments of the coefficients. However, with fine particles many more difficulties are encountered. 6 figures. (DP)

  15. Effects of High-Flow Experiments from Glen Canyon Dam on Abundance, Growth, and Survival Rates of Early Life Stages of Rainbow Trout in the Lees Ferry Reach of the Colorado River

    Science.gov (United States)

    Korman, Josh; Kaplinski, Matthew; Melis, Theodore S.

    2010-01-01

    High-flow experiments (HFEs) from Glen Canyon Dam are primarily intended to conserve fine sediment and improve habitat conditions for native fish in the Colorado River as it flows through Grand Canyon National Park, Arizona. These experimental flows also have the potential to affect the rainbow trout (Oncorhynchus mykiss) population in the Lees Ferry tailwater reach immediately below the dam, which supports a highly valued recreational fishery and likely influences the abundance of rainbow trout in Grand Canyon. Understanding how flow regimes affect the survival and growth of juvenile rainbow trout is critical to interpreting trends in adult abundance. This study reports on the effects of HFEs in 2004 and 2008 on early life stages of rainbow trout in the Lees Ferry reach on the basis of monthly sampling of redds (egg nests) and the abundance of the age-0 trout (fertilization to about 1 to 2 months from emergence) and their growth during a 7-year period between 2003 and 2009. Multiple lines of evidence indicate that the March 2008 HFE resulted in a large increase in early survival rates of age-0 trout because of an improvement in habitat conditions. A stock-recruitment analysis demonstrated that age-0 abundance in July 2008 was more than fourfold higher than expected, given the number of viable eggs that produced these fish. A hatch-date analysis showed that early survival rates were much higher for cohorts that hatched about 1 month after the 2008 HFE (about April 15, 2008) relative to those fish that hatched before this date. These cohorts, fertilized after the 2008 HFE, would have emerged into a benthic invertebrate community that had recovered, and was possibly enhanced by, the HFE. Interannual differences in growth of age-0 trout, determined on the basis of otolith microstructure, support this hypothesis. Growth rates in the summer and fall of 2008 (0.44 mm/day) were virtually the same as in 2006 (0.46 mm/day), the highest recorded during 6 years, even though

  16. Effects of High-Flow Experiments from Glen Canyon Dam on Abundance, Growth, and Survival Rates of Early Life Stages of Rainbow Trout in the Lees Ferry Reach of the Colorado River

    Science.gov (United States)

    Korman, Josh; Kaplinski, Matthew; Melis, Theodore S.

    2010-01-01

    High-flow experiments (HFEs) from Glen Canyon Dam are primarily intended to conserve fine sediment and improve habitat conditions for native fish in the Colorado River as it flows through Grand Canyon National Park, Arizona. These experimental flows also have the potential to affect the rainbow trout (Oncorhynchus mykiss) population in the Lees Ferry tailwater reach immediately below the dam, which supports a highly valued recreational fishery and likely influences the abundance of rainbow trout in Grand Canyon. Understanding how flow regimes affect the survival and growth of juvenile rainbow trout is critical to interpreting trends in adult abundance. This study reports on the effects of HFEs in 2004 and 2008 on early life stages of rainbow trout in the Lees Ferry reach on the basis of monthly sampling of redds (egg nests) and the abundance of the age-0 trout (fertilization to about 1 to 2 months from emergence) and their growth during a 7-year period between 2003 and 2009. Multiple lines of evidence indicate that the March 2008 HFE resulted in a large increase in early survival rates of age-0 trout because of an improvement in habitat conditions. A stock-recruitment analysis demonstrated that age-0 abundance in July 2008 was more than fourfold higher than expected, given the number of viable eggs that produced these fish. A hatch-date analysis showed that early survival rates were much higher for cohorts that hatched about 1 month after the 2008 HFE (about April 15, 2008) relative to those fish that hatched before this date. These cohorts, fertilized after the 2008 HFE, would have emerged into a benthic invertebrate community that had recovered, and was possibly enhanced by, the HFE. Interannual differences in growth of age-0 trout, determined on the basis of otolith microstructure, support this hypothesis. Growth rates in the summer and fall of 2008 (0.44 mm/day) were virtually the same as in 2006 (0.46 mm/day), the highest recorded during 6 years, even though

  17. Ultrasonic 3-D vector flow method for quantitative in vivo peak velocity and flow rate estimation

    DEFF Research Database (Denmark)

    Holbek, Simon; Ewertsen, Caroline; Bouzari, Hamed;

    2017-01-01

    Current clinical ultrasound systems are limited to show blood flow movement in either 1-D or 2-D. In this paper, a method for estimating 3-D vector velocities in a plane using the Transverse Oscillation (TO) method, a 32 x 32 element matrix array, and the experimental ultrasound scanner SARUS...... is presented. The aim of this paper is to estimate precise flow rates and peak velocities derived from 3-D vector flow estimates. The emission sequence provides 3-D vector flow estimates at up to 1.145 frames per second in a plane, and was used to estimate 3-D vector flow in a cross sectional image plane....... The method is validated in two phantom studies, where flow rates are measured in a flow-rig, providing a constant parabolic flow, and in a straight-vessel phantom (ø = 8 mm) connected to a flow pump capable of generating time varying waveforms. Flow rates are estimated to be 82.1 ± 2.8 L/min in the flow...

  18. Influence of Reduced Mass Flow Rate and Chamber Backpressure on Swirl Injector Fluid Mechanics

    Science.gov (United States)

    Kenny, R Jeremy; Hulka, James R.

    2008-01-01

    Industry interest in variable-thrust liquid rocket engines places a demand on engine injector technology to operate over a wide range of liquid mass flow rates and chamber backpressures. One injection technology of current interest for variable thrust applications is an injector design with swirled fluids. Current swirl injector design methodologies do not take into account how swirl injector design parameters respond to elevated chamber backpressures at less than design mass flow rates. The current work was created to improve state-of-the-art swirl injector design methods in this area. The specific objective was to study the effects of elevated chamber backpressure and off-design mass flow rates on swirl injector fluid mechanics. Using a backpressure chamber with optical access, water was flowed through a swirl injector at various combinations of chamber backpressure and mass flow rates. The film thickness profile down the swirl injector nozzle section was measured through a transparent nozzle section of the injector. High speed video showed measurable increases in the film thickness profile with application of chamber backpressure and mass flow rates less than design. At prescribed combinations of chamber backpressure and injected mass flow rate, a discrete change in the film thickness profile was observed. Measured injector discharge coefficient values showed different trends with increasing chamber backpressure at low mass flow rates as opposed to near-design mass flow rates. Downstream spray angles showed classic changes in morphology as the mass flow rate was decreased below the design value. Increasing chamber backpressure decreased the spray angle at any injection mass flow rate. Experimental measurements and discussion of these results are reported in this paper.

  19. Influence of Reduced Mass Flow Rate and Chamber Backpressure on Swirl Injector Fluid Mechanics

    Science.gov (United States)

    Kenny, R Jeremy; Hulka, James R.

    2008-01-01

    Industry interest in variable-thrust liquid rocket engines places a demand on engine injector technology to operate over a wide range of liquid mass flow rates and chamber backpressures. One injection technology of current interest for variable thrust applications is an injector design with swirled fluids. Current swirl injector design methodologies do not take into account how swirl injector design parameters respond to elevated chamber backpressures at less than design mass flow rates. The current work was created to improve state-of-the-art swirl injector design methods in this area. The specific objective was to study the effects of elevated chamber backpressure and off-design mass flow rates on swirl injector fluid mechanics. Using a backpressure chamber with optical access, water was flowed through a swirl injector at various combinations of chamber backpressure and mass flow rates. The film thickness profile down the swirl injector nozzle section was measured through a transparent nozzle section of the injector. High speed video showed measurable increases in the film thickness profile with application of chamber backpressure and mass flow rates less than design. At prescribed combinations of chamber backpressure and injected mass flow rate, a discrete change in the film thickness profile was observed. Measured injector discharge coefficient values showed different trends with increasing chamber backpressure at low mass flow rates as opposed to near-design mass flow rates. Downstream spray angles showed classic changes in morphology as the mass flow rate was decreased below the design value. Increasing chamber backpressure decreased the spray angle at any injection mass flow rate. Experimental measurements and discussion of these results are reported in this paper.

  20. Estimation of Saturation Flow Rates at Signalized Intersections

    Directory of Open Access Journals (Sweden)

    Chang-qiao Shao

    2012-01-01

    Full Text Available The saturation flow rate is a fundamental parameter to measure the intersection capacity and time the traffic signals. However, it is revealed that traditional methods which are mainly developed using the average value of observed queue discharge headways to estimate the saturation headway might lead to underestimate saturation flow rate. The goal of this paper is to study the stochastic nature of queue discharge headways and to develop a more accurate estimate method for saturation headway and saturation flow rate. Based on the surveyed data, the characteristics of queue discharge headways and the estimation method of saturated flow rate are studied. It is found that the average value of queue discharge headways is greater than the median value and that the skewness of the headways is positive. Normal distribution tests were conducted before and after a log transformation of the headways. The goodness-of-fit test showed that for some surveyed sites, the queue discharge headways can be fitted by the normal distribution and for other surveyed sites, the headways can be fitted by lognormal distribution. According to the queue discharge headway characteristics, the median value of queue discharge headways is suggested to estimate the saturation headway and a new method of estimation saturation flow rates is developed.

  1. Doppler-Based Flow Rate Sensing in Microfluidic Channels

    Directory of Open Access Journals (Sweden)

    Liron Stern

    2014-09-01

    Full Text Available We design, fabricate and experimentally demonstrate a novel generic method to detect flow rates and precise changes of flow velocity in microfluidic devices. Using our method we can measure flow rates of ~2 mm/s with a resolution of 0.08 mm/s. The operation principle is based on the Doppler shifting of light diffracted from a self-generated periodic array of bubbles within the channel and using self-heterodyne detection to analyze the diffracted light. As such, the device is appealing for variety of “lab on chip” bio-applications where a simple and accurate speed measurement is needed, e.g., for flow-cytometry and cell sorting.

  2. High-shear-rate capillary viscometer for inkjet inks

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xi [FUJIFILM Dimatix, Inc., Lebanon, New Hampshire 03766 (United States); Carr, Wallace W.; Bucknall, David G. [School of Polymer, Textile, and Fiber Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States); Morris, Jeffrey F. [Department of Chemical Engineering and Benjamin Levich Institute for Physico-Chemical Hydrodynamics, City College of New York, New York, New York 10031 (United States)

    2010-06-15

    A capillary viscometer developed to measure the apparent shear viscosity of inkjet inks at high apparent shear rates encountered during inkjet printing is described. By using the Weissenberg-Rabinowitsch equation, true shear viscosity versus true shear rate is obtained. The device is comprised of a constant-flow generator, a static pressure monitoring device, a high precision submillimeter capillary die, and a high stiffness flow path. The system, which is calibrated using standard Newtonian low-viscosity silicone oil, can be easily operated and maintained. Results for measurement of the shear-rate-dependent viscosity of carbon-black pigmented water-based inkjet inks at shear rates up to 2x10{sup 5} s{sup -1} are discussed. The Cross model was found to closely fit the experimental data. Inkjet ink samples with similar low-shear-rate viscosities exhibited significantly different shear viscosities at high shear rates depending on particle loading.

  3. A MEMS-Based Flow Rate and Flow Direction Sensing Platform with Integrated Temperature Compensation Scheme

    Directory of Open Access Journals (Sweden)

    Chia-Yen Lee

    2009-07-01

    Full Text Available This study develops a MEMS-based low-cost sensing platform for sensing gas flow rate and flow direction comprising four silicon nitride cantilever beams arranged in a cross-form configuration, a circular hot-wire flow meter suspended on a silicon nitride membrane, and an integrated resistive temperature detector (RTD. In the proposed device, the flow rate is inversely derived from the change in the resistance signal of the flow meter when exposed to the sensed air stream. To compensate for the effects of the ambient temperature on the accuracy of the flow rate measurements, the output signal from the flow meter is compensated using the resistance signal generated by the RTD. As air travels over the surface of the cross-form cantilever structure, the upstream cantilevers are deflected in the downward direction, while the downstream cantilevers are deflected in the upward direction. The deflection of the cantilever beams causes a corresponding change in the resistive signals of the piezoresistors patterned on their upper surfaces. The amount by which each beam deflects depends on both the flow rate and the orientation of the beam relative to the direction of the gas flow. Thus, following an appropriate compensation by the temperature-corrected flow rate, the gas flow direction can be determined through a suitable manipulation of the output signals of the four piezoresistors. The experimental results have confirmed that the resulting variation in the output signals of the integrated sensors can be used to determine not only the ambient temperature and the velocity of the air flow, but also its direction relative to the sensor with an accuracy of ± 7.5o error.

  4. A MEMS-Based Flow Rate and Flow Direction Sensing Platform with Integrated Temperature Compensation Scheme.

    Science.gov (United States)

    Ma, Rong-Hua; Wang, Dung-An; Hsueh, Tzu-Han; Lee, Chia-Yen

    2009-01-01

    This study develops a MEMS-based low-cost sensing platform for sensing gas flow rate and flow direction comprising four silicon nitride cantilever beams arranged in a cross-form configuration, a circular hot-wire flow meter suspended on a silicon nitride membrane, and an integrated resistive temperature detector (RTD). In the proposed device, the flow rate is inversely derived from the change in the resistance signal of the flow meter when exposed to the sensed air stream. To compensate for the effects of the ambient temperature on the accuracy of the flow rate measurements, the output signal from the flow meter is compensated using the resistance signal generated by the RTD. As air travels over the surface of the cross-form cantilever structure, the upstream cantilevers are deflected in the downward direction, while the downstream cantilevers are deflected in the upward direction. The deflection of the cantilever beams causes a corresponding change in the resistive signals of the piezoresistors patterned on their upper surfaces. The amount by which each beam deflects depends on both the flow rate and the orientation of the beam relative to the direction of the gas flow. Thus, following an appropriate compensation by the temperature-corrected flow rate, the gas flow direction can be determined through a suitable manipulation of the output signals of the four piezoresistors. The experimental results have confirmed that the resulting variation in the output signals of the integrated sensors can be used to determine not only the ambient temperature and the velocity of the air flow, but also its direction relative to the sensor with an accuracy of ± 7.5° error.

  5. Flow Rate of He Ⅱ Liquid-Vapor Phase Separator

    Institute of Scientific and Technical Information of China (English)

    Xingen YU; Qing LI; Qiang LI; Zhengyu LI

    2005-01-01

    Experimental results are presented for superfluld (He Ⅱ) flow through porous plug liquid-vapor phase separators.Tests have been performed on seven porous plugs with different thicknesses or different permeabilities. The temperature was measured from 1.5K to 1.9K. Two flow regions were observed in small and large pressure and temperature differences regions respectively. The experimental data are compared with theoretical predictions.The performance and applicability of the basic theory are discussed. Hysteresis of the flow rate is also observed and discussed.

  6. Compressibility, turbulence and high speed flow

    CERN Document Server

    Gatski, Thomas B

    2013-01-01

    Compressibility, Turbulence and High Speed Flow introduces the reader to the field of compressible turbulence and compressible turbulent flows across a broad speed range, through a unique complimentary treatment of both the theoretical foundations and the measurement and analysis tools currently used. The book provides the reader with the necessary background and current trends in the theoretical and experimental aspects of compressible turbulent flows and compressible turbulence. Detailed derivations of the pertinent equations describing the motion of such turbulent flows is provided and

  7. Effects of N2/O2 flow rate on the surface properties and biocompatibility of nano-structured TiOxNy thin films prepared by high vacuum magnetron sputtering

    Science.gov (United States)

    Saleem, Sehrish; Ahmad, R.; Ikhlaq, Uzma; Ayub, R.; Wei, Hong Jin; Rui Zhen, Xu; Peng, Hui Li; Abbas, Khizra; Chu, Paul K.

    2015-07-01

    NiTi shape memory alloys (SMA) have many biomedical applications due to their excellent mechanical and biocompatible properties. However, nickel in the alloy may cause allergic and toxic reactions, which limit some applications. In this work, titanium oxynitride films were deposited on NiTi samples by high vacuum magnetron sputtering for various nitrogen and oxygen gas flow rates. The x-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) results reveal the presence of different phases in the titanium oxynitride thin films. Energy dispersive spectroscopy (EDS) elemental mapping of samples after immersion in simulated body fluids (SBF) shows that Ni is depleted from the surface and cell cultures corroborate the enhanced biocompatibility in vitro. Project supported by the Higher Education Commission, Hong Kong Research Grants Council (RGC) General Research Funds (GRF), China (Grant No. 112212) and the City University of Hong Kong Applied Research Grant (ARG), China (Grant No. 9667066).

  8. Debris flows and cosmogenic catchment wide denudation rates

    Science.gov (United States)

    Kober, F.; Hippe, K.; Salcher, B.; Ivy-Ochs, S.; Kubik, P. W.; Christl, M.; Wacker, L.

    2012-04-01

    One of the basic question in alpine Quantitative Geomorphology is: Are widely measured cosmogenic nuclide-derived denudation rates in alpine catchments truly representative for the whole catchment at any given time? Or in contrast can they vary markedly in response to extreme events and perturbations? And if such perturbations affect cosmogenic nuclide-derived denudation rates then what bias can occur when such denudation rates are compared with sediment yield or thermochronological data or to various morphometric parameters, such as slope, mean elevation or uplift rates as potential controlling factors? We present 10Be and 14C results measured in sand samples from an active river channel from a single catchment (upper Aare), in the Swiss Alps (up to monthly sampling between 2008 to 2011). Our goal was to establish a time series to see if extreme events (such as landslides or debris flows) do have a discernible effect on derived denudation rates. The admixture of sediment of debris flows in 2009, originating upstream of the sampling spot, began to have a marked effect on 10Be concentrations and thus catchment wide denudation rates that are assumed to be in a long-term range mode prior to 2009. In summer of 2010, several extreme debris flows were recorded in the studied catchment. Samples taken document a doubling of denudation rates over the values determined from 2008. These cosmogenic nuclide data clearly demonstrate the impact of episodic events on sediment flux and the related perturbation of catchment wide denudation rates. We have recently expanded this dataset into 2011, with i) a spatial sub-sampling of debris flow and non-debris flow catchment compartments and ii) including again a major debris flow event in early autumn 2011. These data will be presented at the conference. Never-the-less the fact that the CWDR's only doubled does suggest a certain robustness in the method beyond a certain catchment size. In addition to the 10Be data, in situ 14C

  9. Efficiencies of flat plate solar collectors at different flow rates

    DEFF Research Database (Denmark)

    Chen, Ziqian; Furbo, Simon; Perers, Bengt;

    2012-01-01

    Two flat plate solar collectors for solar heating plants from Arcon Solvarme A/S are tested in a laboratory test facility for solar collectors at Technical University of Denmark (DTU). The collectors are designed in the same way. However, one collector is equipped with an ETFE foil between...... the absorber and the cover glass and the other is without ETFE foil. The efficiencies for the collectors are tested at different flow rates. On the basis of the measured efficiencies, the efficiencies for the collectors as functions of flow rate are obtained. The calculated efficiencies are in good agreement...

  10. Kinetic assessment of measured mass flow rates and streamwise pressure distributions in microchannel gas flows

    Institute of Scientific and Technical Information of China (English)

    Jing Fan; Chong Xie; Jianzheng Jiang

    2007-01-01

    Measured mass flow rates and streamwise pressure distributions of gas flowing through microchannels were reported by many researchers. Assessment of these data is crucial before they are used in the examination of slip models and numerical schemes, and in the design of microchannel elements in various MEMS devices. On the basis of kinetic solutions of the mass flow rates and pressure distributions in microchannel gas flows, the measured data available are properly normalized and then are compared with each other. The 69 normalized data of measured pressure distributions are in excellent agreement, and 67 of them are within 1 ± 0.05. The normalized data of mass flow-rates ranging between 0.95 and 1 agree well with each other as the inlet Knudsen number Kni > 0.02, but they scat ter between 0.85 and 1.15 as Kni < 0.02 with, to some extent, a very interesting bifurcation trend.

  11. Homogenization of High-Contrast Brinkman Flows

    KAUST Repository

    Brown, Donald L.

    2015-04-16

    Modeling porous flow in complex media is a challenging problem. Not only is the problem inherently multiscale but, due to high contrast in permeability values, flow velocities may differ greatly throughout the medium. To avoid complicated interface conditions, the Brinkman model is often used for such flows [O. Iliev, R. Lazarov, and J. Willems, Multiscale Model. Simul., 9 (2011), pp. 1350--1372]. Instead of permeability variations and contrast being contained in the geometric media structure, this information is contained in a highly varying and high-contrast coefficient. In this work, we present two main contributions. First, we develop a novel homogenization procedure for the high-contrast Brinkman equations by constructing correctors and carefully estimating the residuals. Understanding the relationship between scales and contrast values is critical to obtaining useful estimates. Therefore, standard convergence-based homogenization techniques [G. A. Chechkin, A. L. Piatniski, and A. S. Shamev, Homogenization: Methods and Applications, Transl. Math. Monogr. 234, American Mathematical Society, Providence, RI, 2007, G. Allaire, SIAM J. Math. Anal., 23 (1992), pp. 1482--1518], although a powerful tool, are not applicable here. Our second point is that the Brinkman equations, in certain scaling regimes, are invariant under homogenization. Unlike in the case of Stokes-to-Darcy homogenization [D. Brown, P. Popov, and Y. Efendiev, GEM Int. J. Geomath., 2 (2011), pp. 281--305, E. Marusic-Paloka and A. Mikelic, Boll. Un. Mat. Ital. A (7), 10 (1996), pp. 661--671], the results presented here under certain velocity regimes yield a Brinkman-to-Brinkman upscaling that allows using a single software platform to compute on both microscales and macroscales. In this paper, we discuss the homogenized Brinkman equations. We derive auxiliary cell problems to build correctors and calculate effective coefficients for certain velocity regimes. Due to the boundary effects, we construct

  12. Impact of increased flow rate on specific growth rate of juvenile turbot (Scophthalmus maximus, Rafinesque 1810)

    NARCIS (Netherlands)

    Schram, E.; Verdegem, M.C.J.; Widjaja, R.T.O.B.H.; Kloet, C.J.; Foss, A.; Schelvis-Smit, A.A.M.

    2009-01-01

    The effect of flow rate on growth was investigated in juvenile turbot. Fish with a mean (SD) initial weight of 102 (10.4) g were reared at 6 different flow rates, equaling 1, 2, 3, 4, 6 or 8 tank volumes/h in 196 L tanks during 29 days at 18 ± 0.29 °C, a salinity of 18.0 ± 0.77¿ and a pH ranging

  13. Controlling Surface Roughness to Enhance Mass Flow Rates in Nanochannels

    Science.gov (United States)

    Zimon, Malgorzata; Emerson, David; Reese, Jason

    2012-11-01

    A very active field of research in fluid mechanics and material science is predicting the behavior of Newtonian fluids flowing over porous media with different wettabilities. Opposite effects have been observed: some state that wall roughness always suppresses fluid-slip, whereas others show that for some cases roughness may reduce the surface friction. In this work, MD simulations were carried out to further investigate physical mechanisms for liquid slip, and factors affecting it. A rough wall was formed by either periodically spaced rectangular protrusions or was represented by a cosine wave. The MD simulations were conducted to study Poiseuille and Couette flow of liquid argon in a nanochannel with hydrophilic kryptonian walls. The effect of wall roughness and interface wettability on the streaming velocity, and the slip-length at the walls, is observed to be significant. Our results show a dependency of mass flow rate on the type of flow and topography of the channel walls. For a fixed magnitude of the driving force, an increase in the mass flow rate, compared to the smooth surface, was observed for the wavy roughness, whereas the opposite effect was observed for Couette flow where a higher slip was obtained for rectangular gaps. The study is funded in the UK by the Engineering and Physical Sciences Research Council.

  14. Flow-rate Characteristics Measurement of Regulators Based on the Pressure Response in an Isothermal Tank

    Institute of Scientific and Technical Information of China (English)

    FAN Wei; ZHANG Hongli; WANG Tao; PENG Guangzheng; ONEYAMA Naotake

    2009-01-01

    Regulators are important components in pneumatic system, and their flow-rate characteristics are the key parameters for designers. According to the correlatively international standard and national standard of China, which describe the flow-rate characteristics measurement method of pneumatic regulators, the pressure and the flow are measured point by point, and then the flow-rate characteristics curve is plotted point to point. This method has some disadvantages, such as equipment complexity, much air consumption, and low efficiency. To settle the problems presented above, this paper puts forward a new high efficient and energy saving flow-rate characteristics measurement method of regulators, which is based on the pressure response when charging and discharging to an isothermal tank without any flow meters. The measurement principle, the system and the steps are introduced. And the tracking differentiator is used for the data processing of the pressure difference. Two typical kinds of regulators were experimentally investigated, and their flow-rate characteristics curves were obtained with the new and the conventional method, respectively. Comparatively, it's proved that this new method is feasible because it is not only able to meet the demand of the measurement precision, but also to save energy and improve efficiency. Compared to the conventional method, the new method takes only about 1/10 amount of time and consumes about only 1/30 amount of air. Hopefully it will be able to serve as an international standard of flow-rate characteristics measurement method of regulators.

  15. Autism's 'Worryingly' High Suicide Rates Spur Conference

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_165946.html Autism's 'Worryingly' High Suicide Rates Spur Conference Signs of ... News) -- High rates of suicide among people with autism are drawing specialists to a conference this week ...

  16. Numerical Simulation of Muzzle Flow Field for Super-high Firing-rate Series Launched Weapon%超高射频武器串联发射膛口流场数值模拟

    Institute of Scientific and Technical Information of China (English)

    张学伟; 李强; 刘武; 张正涛

    2016-01-01

    A study is made of the muzzle flow field and the influence on the projectile flying of the su-per-high firing-rate series launched weapon based on the ALE equation and chimera grids technology, in combination with dynamic grid method. The result clearly reveals that complex muzzle flow field structure of complicated gunpowder gas was formed in the process of the high firing-rate. In addition, under the same explosive charge,on the high firing-rate,the acceleration of the following projectile is far less than that of the first one. The following projectile outside the barrel,the gunpowder gas before the projectile expansion formed a low pressure area,while the pressure after the projectile is higher than the first,so that acceleration for the following projectile is greater than that for the first projectile. The simulation results provide some theoretical basis for the study of the rapid-fire strong coupling launch projectile force analysis.%为了研究超高射频武器高频连发时膛口流场形成机理和对弹丸飞行的影响,基于 ALE方程和嵌入网格技术,结合动网格方法进行数值仿真分析。数值结果清晰地揭示了高频连发时火药气体相互叠加形成的复杂流场的结构。在相同装药量下,高频连发时后续弹丸膛内加速度远小于首发弹丸;后续弹丸出膛口后,弹前火药燃气膨胀形成低压区,而弹后压力高于首发弹丸弹后压力,使其加速度大于首发弹丸。仿真结果为研究超高射频武器高频连发时弹丸受力分析提供一些理论依据。

  17. Assessment of salivary flow rate: biologic variation and measure error.

    NARCIS (Netherlands)

    Jongerius, P.H.; Limbeek, J. van; Rotteveel, J.J.

    2004-01-01

    OBJECTIVE: To investigate the applicability of the swab method in the measurement of salivary flow rate in multiple-handicap drooling children. To quantify the measurement error of the procedure and the biologic variation in the population. STUDY DESIGN: Cohort study. METHODS: In a repeated measurem

  18. High Flow Nasal Cannulae in preterm infants

    Directory of Open Access Journals (Sweden)

    F. Ciuffini

    2013-06-01

    Full Text Available Despite of improved survival of premature infants, the incidence of long term pulmonary complications, mostly associated with ventilation-induced lung injury, remains high. Non invasive ventilation (NIV is able to reduce the adverse effects of mechanical ventilation. Although nasal continuous positive airway pressure (NCPAP is an effective mode of NIV, traumatic nasal complications and intolerance of the nasal interface are common. Recently high flow nasal cannula (HFNC is emerging as an efficient, better tolerated form of NIV, allowing better access to the baby’s face, which may improve nursing, feeding and bonding. The aim of this review is to discuss the available evidence of effectiveness and safety of HFNC in preterm newborns with respiratory distress syndrome (RDS. It is known that distending pressure generated by HFNC increases with increasing flow rate and decreasing infant size and varies according to the amount of leaks by nose and mouth. The effects of HFNC on lung mechanics, its clinical efficacy and safety are still insufficiently investigated. In conclusion, there is a growing evidence of the feasibility of HFNC as an alternative mode of NIV. However, further larger randomized trials are required, before being able to recommend HFNC in the treatment of moderate respiratory distress of preterm infants.

  19. Proposed method for measurement of flow rate in turbulent periodic pipe flow

    Science.gov (United States)

    Werzner, E.; Ray, S.; Trimis, D.

    2011-12-01

    The present investigation deals with a previously proposed flow metering technique for laminar, fully-developed, time-periodic pipe flow. Employing knowledge of the pulsation frequency-dependent relationship between the mass flow rate and the pressure gradient, the method allows reconstruction of the instantaneous mass flow rate on the basis of a recorded pressure gradient time series. In order to explore if the procedure can be extended for turbulent flows, numerical simulations for turbulent, fully-developed, sinusoidally pulsating pipe flow with low pulse amplitude have been carried out using a ν2-f turbulence model. The study covers pulsation frequencies, ranging from the quasi-steady up to the inertia-dominated frequency regime, and three cycle-averaged Reynolds numbers of 4360, 9750 and 15400. After providing the theoretical background of the flow rate reconstruction principle, the numerical model and an experimental facility for the verification of simulations are explained. The obtained results, presented in time and frequency domain, show good agreement with each other and indicate a frequency dependence, similar to that used for the signal reconstruction for laminar flows. A modified dimensionless frequency definition has been introduced, which allows a generalised representation of the results considering the influence of Reynolds number.

  20. Dividend growth, cash flow, and discount rate news

    OpenAIRE

    Garrett, Ian; Priestley, Richard

    2012-01-01

    Using a new variable based on a model of dividend smoothing, we find that dividend growth is highly predictable and that cash flow news contributes importantly to return variability. Cash flow betas derived from this predictability are central to explaining the size effect in the cross section of returns. However, they do not explain the value effect; this is explained by noise betas. We also find that the relative importance of cash flow news in explaining recent stock price run-ups and subs...

  1. Dividend growth, cash flow, and discount rate news

    OpenAIRE

    Garrett, Ian; Priestley, Richard

    2012-01-01

    Using a new variable based on a model of dividend smoothing, we find that dividend growth is highly predictable and that cash flow news contributes importantly to return variability. Cash flow betas derived from this predictability are central to explaining the size effect in the cross section of returns. However, they do not explain the value effect; this is explained by noise betas. We also find that the relative importance of cash flow news in explaining recent stock price run-ups and subs...

  2. High-Frame-Rate Oil Film Interferometry

    CERN Document Server

    White, Jonathan C; Chen, John

    2010-01-01

    The fluid dynamics video to which this abstract relates contains visualization of the response of a laminar boundary layer to a sudden puff from a small hole. The boundary layer develops on a flat plate in a wind tunnel; the hole is located at a streamwise Reynolds number of 100,000. The visualization of the boundary layer response is accomplished using interferometry of a transparent, thin film of oil placed on the surface immediately downstream of the hole and with its leading edge perpendicular to the direction of flow. Through lubrication theory, it is understood that the rate of change of the spacing of the interference fringes is proportional to the skin friction at any instant. For reference, a small disk-shaped protrusion of the type often used to trip the boundary layer in wind model tunnel testing is also shown. Three cases with different puff strengths are included. Using a high-speed commercial camera, frame rates in excess of 1000/sec have been recorded; the video shown here was taken at 24 frame...

  3. Direct Measurement of Planar Flow Rate in Excised Canine Larynx Model

    Science.gov (United States)

    Oren, Liran; Khosla, Sid; Dembinski, Doug; Ying, Jun; Gutmark, Ephraim

    2014-01-01

    Objective During phonation, skewing of the glottal flow waveform (Q) during phonation refers to a phenomenon that occurs when the flow decelerates more rapidly than it accelerates. This skewing is clinically important because it increases the glottal efficiency, which is defined by the acoustic intensity (units are sound pressure level or SPL) divided by the subglottal pressure. Current theoretical models predict that the only mechanism to cause skewing of Q involves changes in the vocal tract inertance. The purpose of the current work is to show that other factors at the vocal fold level can also cause skewing of Q and to determine if the acoustic intensity is correlated with MFDR. Study design Basic Science Methods Intraglottal geometry and velocity measurements were taken in five canine larynges at the mid-membranous plane using two-dimensional particle imaging velocimetry (PIV). The flow rate at the glottal exit was computed from the PIV measurements for low, medium, and high subglottal pressures. Results Vortices form in the superior aspect of the divergent glottis during closing. These vortices produce negative pressure that increases both the maximum value of Q and the rapid deceleration of the flow. The skewing of the flow rate is increased as the intraglottal vortices are increased by increasing the subglottal pressure. The increase in the acoustic intensity is highly correlated with certain properties of the flow rate waveform, such as maximum flow rate. Conclusion Flow skewing and the acoustic intensity can be increased by increasing the intraglottal vortices. PMID:25093928

  4. Flow rate dependency of critical wall shear stress in a radial-flow cell

    DEFF Research Database (Denmark)

    Detry, J.G.; Jensen, Bo Boye Busk; Sindic, M.

    2009-01-01

    of a water or ethanol suspension of starch granules on the surfaces. Depending on the substrate and on the suspending liquid, the aggregates differed in size and shape. Aggregate removal was studied at two flow rates. At the lower flow rate (Re-inlet = 955), the values of critical wall shear stress......In the present work, a radial-flow cell was used to study the removal of starch particle aggregates from several solid substrates (glass, stainless steel, polystyrene and PTFE) in order to determine the critical wall shear stress value for each case. The particle aggregates were formed by aspersion...... for the different surfaces suggested that capillary forces were, for all of them, playing an important role in aggregate adhesion since aqueous based aggregates were always more difficult to remove. At the higher flow rate (Re-inlet = 2016) the critical wall shear stress increased as a result of the change...

  5. Research in high flow therapy: mechanisms of action.

    Science.gov (United States)

    Dysart, Kevin; Miller, Thomas L; Wolfson, Marla R; Shaffer, Thomas H

    2009-10-01

    Recently, heater/humidifier devices that use novel methods to condition breathing gases from an external source have been introduced. The addition of sufficient warmth and high levels of humidification to breathing gas has allowed for higher flow rates from nasal cannula devices to be applied to patients (i.e., high flow therapy). This article provides a review of the proposed mechanisms behind the efficacy of high flow therapy via nasal cannula, which include washout of nasopharyngeal dead space, attenuation of the inspiratory resistance associated with the nasopharynx, improvement in conductance and pulmonary compliance, mild distending pressure and reduction in energy expenditure for gas conditioning.

  6. Macropore system characteristics controls on non-reactive solute transport at different flow rates

    Science.gov (United States)

    Larsbo, Mats; Koestel, John

    2014-05-01

    Preferential flow and transport in macroporous soils are important pathways for the leaching of agrochemicals through soils. Preferential solute transport in soil is to a large extent determined by the macropore system characteristics and the water flow conditions. The importance of different characteristics of the macropore system is likely to vary with the flow conditions. The objective of this study was to determine which properties of the macropore system that control the shape of non-reactive tracer solute breakthrough curves at different steady-state flow rates. We sampled five undisturbed columns (20 cm high, 20 cm diameter) from the soil surface of four soils with clay contents between 21 and 50 %. Solute transport experiments were carried out under unsaturated conditions at 2, 4, 6, 8 and 12 mm h-1 flow rates. For each flow rate a pulse of potassium bromide solution was applied at the soil surface and the electrical conductivity was measured with high temporal resolution in the column effluent. We used the 5 % arrival time and the holdback factor to estimate the degree of preferential transport from the resulting breakthrough curves. Unsaturated hydraulic conductivities were measured at the soil surface of the columns using a tension disc infiltrometer. The macropore system was imaged by industrial X-ray computed tomography at a resolution of 125 μm in all directions. Measures of the macropore system characteristics including measures of pore continuity were calculated from these images using the ImageJ software. Results show that the degree of preferential transport is generally increasing with flow rate when larger pores become active in the transport. The degree of preferential flow was correlated to measures of macropore topology. This study show that conclusions drawn from experiments carried out at one flow rate should generally not be extrapolated to other flow rates.

  7. Propellant flow rate through simulated liquid-core nuclear rocket fuel bed.

    Science.gov (United States)

    Mcguirk, J. P.; Park, C.

    1972-01-01

    Experimental investigation of the validity of Zuber and Finlay's (1965) gas flow-rate formula for a two-phase flow in a rotating cylinder under high centrifugal acceleration. This formula was originally derived from tests in a 1-g environment in pipes. In the light of the investigation results obtained, the formula is valid also for a high-g environment in the rotating chamber tested.

  8. High-Throughput Continuous Flow Production of Nanoscale Liposomes by Microfluidic Vertical Flow Focusing.

    Science.gov (United States)

    Hood, Renee R; DeVoe, Don L

    2015-11-18

    Liposomes represent a leading class of nanoparticles for drug delivery. While a variety of techniques for liposome synthesis have been reported that take advantage of microfluidic flow elements to achieve precise control over the size and polydispersity of nanoscale liposomes, with important implications for nanomedicine applications, these methods suffer from extremely limited throughput, making them impractical for large-scale nanoparticle synthesis. High aspect ratio microfluidic vertical flow focusing is investigated here as a new approach to overcoming the throughput limits of established microfluidic nanoparticle synthesis techniques. Here the vertical flow focusing technique is utilized to generate populations of small, unilamellar, and nearly monodisperse liposomal nanoparticles with exceptionally high production rates and remarkable sample homogeneity. By leveraging this platform, liposomes with modal diameters ranging from 80 to 200 nm are prepared at production rates as high as 1.6 mg min(-1) in a simple flow-through process.

  9. Effect of air-flow rate and turning frequency on bio-drying of dewatered sludge.

    Science.gov (United States)

    Zhao, Ling; Gu, Wei-Mei; He, Pin-Jing; Shao, Li-Ming

    2010-12-01

    Sludge bio-drying is an approach for biomass energy utilization, in which sludge is dried by means of the heat generated by aerobic degradation of its organic substances. The study aimed at investigating the interactive influence of air-flow rate and turning frequency on water removal and biomass energy utilization. Results showed that a higher air-flow rate (0.0909m(3)h(-1)kg(-1)) led to lower temperature than did the lower one (0.0455m(3)h(-1)kg(-1)) by 17.0% and 13.7% under turning per two days and four days. With the higher air-flow rate and lower turning frequency, temperature cumulation was almost similar to that with the lower air-flow rate and higher turning frequency. The doubled air-flow rate improved the total water removal ratio by 2.86% (19.5gkg(-1) initial water) and 11.5% (75.0gkg(-1) initial water) with turning per two days and four days respectively, indicating that there was no remarkable advantage for water removal with high air-flow rate, especially with high turning frequency. The heat used for evaporation was 60.6-72.6% of the total heat consumption (34,400-45,400kJ). The higher air-flow rate enhanced volatile solids (VS) degradation thus improving heat generation by 1.95% (800kJ) and 8.96% (3200kJ) with turning per two days and four days. With the higher air-flow rate, heat consumed by sensible heat of inlet air and heat utilization efficiency for evaporation was higher than the lower one. With the higher turning frequency, sensible heat of materials and heat consumed by turning was higher than lower one.

  10. Vacuum rated flow controllers for inert gas ion engines

    Science.gov (United States)

    Pless, L. C.

    1987-01-01

    Electrical propulsion systems which use a gas as a propellant require a gas flowmeter/controller which is capable of operating in a vacuum environment. The presently available instruments in the required flow ranges are designed and calibrated for use at ambient pressure. These instruments operate by heating a small diameter tube through which the gas is flowing and then sensing the change in temperature along the length of the tube. This temperature change is a function of the flow rate and the gas heat capacity. When installed in a vacuum, the change in the external thermal characteristics cause the tube to overheat and the temperature sensors are then operating outside their calibrated range. In addition, the variation in heat capacity with temperature limit the accuracy obtainable. These problems and the work in progress to solve them are discussed.

  11. Mass flow-rate control through time periodic electro-osmotic flows in circular microchannels

    Science.gov (United States)

    Chakraborty, Suman; Ray, Subhashis

    2008-08-01

    The present study is directed towards devising a scientific strategy for obtaining controlled time-periodic mass flow-rate characteristics through the employment of pulsating electric fields in circular microchannels by exploiting certain intrinsic characteristics of periodic electro-osmosis phenomenon. Within the assumption of thin electrical double layers, the governing equations for potential distribution and fluid flow are derived, corresponding to a steady base state and a time-varying perturbed state, by assuming periodic forms of the imposed electrical fields and the resultant velocity fields. For sinusoidal pulsations of the electric field superimposed over its mean, a signature map depicting the amplitudes of the mass flow rate and the electrical field as well as their phase differences is obtained from the theoretical analysis as a function of a nondimensional frequency parameter for different ratios of the characteristic electric double layer thickness relative to the microchannel radius. Distinctive characteristics in the signature profiles are obtained for lower and higher frequencies, primarily attributed to the finite time scale for momentum propagation away from the walls. The signature characteristics, obtained from the solution of the prescribed sinusoidal electric field, are subsequently used to solve the "inverse" problem, where the mass flow rate is prescribed in the form of sinusoidal pulsations and the desired electric fields that would produce the required mass flow-rate variations are obtained. The analysis is subsequently extended for controlled triangular and trapezoidal pulsations in the mass flow rate and the required electric fields are successfully obtained. It is observed that the higher the double layer thickness is in comparison to the channel radius, the more prominent is the deviation of the shape of the required electric field pulsation from the desired transience in the mass flow-rate characteristics. Possible extensions of the

  12. Stretching Behavior of Red Blood Cells at High Strain Rates

    Science.gov (United States)

    Mancuso, Jordan; Ristenpart, William

    2016-11-01

    Most work on the mechanical behavior of red blood cells (RBCs) has focused on simple shear flows. Relatively little work has examined RBC deformations in the physiologically important extensional flow that occurs at the entrance to a constriction. In particular, previous work suggests that RBCs rapidly stretch out and then retract upon entering the constriction, but to date no model predicts this behavior for the extremely high strain rates typically experienced there. In this work, we use high speed video to perform systematic measurements of the dynamic stretching behavior of RBCs as they enter a microfluidic constriction. We demonstrate that a simple viscoelastic model captures the observed stretching dynamics, up to strain rates as high as 1000 s-1. The results indicate that the effective elastic modulus of the RBC membrane at these strain rates is an order of magnitude larger than moduli measured by micropipette aspiration or other low strain rate techniques.

  13. Variation analysis of flow rate delivered using a blister pump

    Science.gov (United States)

    Selvakumar, Sivesh; Linares, Rodrigo; Oppenheimer, Aaron; Anthony, Brian

    2012-03-01

    Components for on-chip storage and delivery of liquid reagent are necessary for many commercial applications of lab-on- a-chip technology. One such system uses a 'blister-pack' that is pushed by an actuator. This paper explores the sensitivity of the flow rate produced by a blister-actuator pair to the expected manufacturing variations in its dimensions. A numerical model of the blister-actuator pair is developed and the tool of Variation Simulation Modeling (VSM) is used to determine the robustness of fluid delivery. For a flow-rate requirement of +/- 10%, the number of out-of-spec parts is found to be less than 0.01%. The critical dimensions that need to be controlled to improve robustness are also identified.

  14. THE OPTIMIZATION OF FLOW RATES OF AN EXTRUDER

    Directory of Open Access Journals (Sweden)

    I.O. Popoola

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: The article addresses how the flow rates of an extruder can be optimized. It mentions the plastic recycling industry as an example, which is only one of many solid waste recycling industries. The literature on flow rates is reviewed to demonstrate a gap that the current study aims to fills, in the hope that it will stimulate further research in a fertile area.

    AFRIKAANSE OPSOMMING: Die artikel adresseer die vraagstuk van vloeitempo van ‘n ekstrusieproses. Dit handel met ‘n voorbeeld van ‘n plastiekherwinningsproses wat spruit uit soliede afvalverwerking. ‘n Literatuurstudie toon hoedat die navorsing verdere areas wat braak lê, aanspreek in die hoop dat verdere studie gestimuleer sal word.

  15. Measurement of cerebral blood flow rate and its relationship with brain function using optical coherence tomography

    Science.gov (United States)

    Liu, Jian; Wang, Yi; Zhao, Yuqian; Dou, Shidan; Ma, Yushu; Ma, Zhenhe

    2016-03-01

    Activity of brain neurons will lead to changes in local blood flow rate (BFR). Thus, it is important to measure the local BFR of cerebral cortex on research of neuron activity in vivo, such as rehabilitation evaluation after stroke, etc. Currently, laser Doppler flowmetry is commonly used for blood flow measurement, however, relatively low resolution limits its application. Optical coherence tomography (OCT) is a powerful noninvasive 3D imaging modality with high temporal and spatial resolutions. Furthermore, OCT can provide flow distribution image by calculating Doppler frequency shift which makes it possible for blood flow rate measurement. In this paper, we applied OCT to measure the blood flow rate of the primary motor cortex in rats. The animal was immobilized and anesthetized with isoflurane, an incision was made along the sagittal suture, and bone was exposed. A skull window was opened on the primary motor cortex. Then, blood flow rate changes in the primary motor cortex were monitored by our homemade spectral domain OCT with a stimulation of the passive movement of the front legs. Finally, we established the relationship between blood flow rate and the test design. The aim is to demonstrate the potential of OCT in the evaluation of cerebral cortex function.

  16. A flux monitoring method for easy and accurate flow rate measurement in pressure-driven flows.

    Science.gov (United States)

    Siria, Alessandro; Biance, Anne-Laure; Ybert, Christophe; Bocquet, Lydéric

    2012-03-07

    We propose a low-cost and versatile method to measure flow rate in microfluidic channels under pressure-driven flows, thereby providing a simple characterization of the hydrodynamic permeability of the system. The technique is inspired by the current monitoring method usually employed to characterize electro-osmotic flows, and makes use of the measurement of the time-dependent electric resistance inside the channel associated with a moving salt front. We have successfully tested the method in a micrometer-size channel, as well as in a complex microfluidic channel with a varying cross-section, demonstrating its ability in detecting internal shape variations.

  17. Innovative model-based flow rate optimization for vanadium redox flow batteries

    Science.gov (United States)

    König, S.; Suriyah, M. R.; Leibfried, T.

    2016-11-01

    In this paper, an innovative approach is presented to optimize the flow rate of a 6-kW vanadium redox flow battery with realistic stack dimensions. Efficiency is derived using a multi-physics battery model and a newly proposed instantaneous efficiency determination technique. An optimization algorithm is applied to identify optimal flow rates for operation points defined by state-of-charge (SoC) and current. The proposed method is evaluated against the conventional approach of applying Faraday's first law of electrolysis, scaled to the so-called flow factor. To make a fair comparison, the flow factor is also optimized by simulating cycles with different charging/discharging currents. It is shown through the obtained results that the efficiency is increased by up to 1.2% points; in addition, discharge capacity is also increased by up to 1.0 kWh or 5.4%. Detailed loss analysis is carried out for the cycles with maximum and minimum charging/discharging currents. It is shown that the proposed method minimizes the sum of losses caused by concentration over-potential, pumping and diffusion. Furthermore, for the deployed Nafion 115 membrane, it is observed that diffusion losses increase with stack SoC. Therefore, to decrease stack SoC and lower diffusion losses, a higher flow rate during charging than during discharging is reasonable.

  18. A correction to collision rates of droplets in turbulent flows

    CERN Document Server

    Zhang, Huang

    2016-01-01

    This paper makes a correction to the collision rates of small droplets in turbulent fluid derived by Saffman and Turner(1956). Not only the distortion but also the rotation of the fluid is taken into account between two close droplets. A rotation reference is fixed on one drop, and the fluxes of the other drops moving towards the fixed one are carried out based on this new reference. The behaviors of turbulent flow are analyzed within the smallest eddies under the rotation reference, and a correction is made to the collision rates by multiplying a factor sqrt(2).

  19. Understanding High Rate Behavior Through Low Rate Analog

    Science.gov (United States)

    2014-04-28

    Dioh, N.N., et al., The High-Strain Rate Behavior of Polymers. Journal De Physique Iv, 1994. 4(C8): p. 119-124. 21. Dioh, N.N., P.S. Leevers, and J.G...constitutive response of polymeric materials as a function of temperature and strain rate. Journal De Physique Iv, 2003. 110: p. 27-32. 23. Brown, E.N...properties of polycarbonate under dynamic loading. Journal De Physique Iv, 2003. 110: p. 159-164. 56. Li, Z.H. and J. Lambros, Strain rate effects on the

  20. Assessment of Average Tracer Concentration Approach for Flow Rate Measurement and Field Calibration

    Directory of Open Access Journals (Sweden)

    P. Sidauruk

    2015-12-01

    Full Text Available Tracer method is one of the methods available for open channel flow rate measurements such as in irrigation canals. Average tracer concentration approach is an instantaneous injection method that based on the average tracer concentrations value at the sampling point. If the procedures are correct and scientific considerations are justified, tracer method will give relatively high accuracy of measurements. The accuracy of the average tracer concentration approach has been assessed both in laboratory and field. The results of accuracy tests of open channel flow that has been conducted at the Center for Application Isotopes and Radiation Laboratory-BATAN showed that the accuracy level of average concentrations approach method was higher than 90% compared to the true value (volumetric flow rate. The accuracy of average tracer concentration approach was also assessed during the application of the method to measure flow rate of Mrican irrigation canals as an effort to perform field calibration of existing weirs. Both average tracer concentration approach and weirs can predict the trend of the flow correctly. However, it was observed that flow discrepancies between weirs measurement and average tracer concentration approach predictions were as high as 27%. The discrepancies might be due to the downgrading performances of the weirs because of previous floods and high sediment contents of the flow

  1. Relationship between Formation Water Rate, Equivalent Penetration Rate and Volume Flow Rate of Air in Air Drilling

    Institute of Scientific and Technical Information of China (English)

    Wang Kexiong; Zhang Laibin; Jiang Hongwei

    2007-01-01

    Formation water invasion is the most troublesome problem associated with air drilling. However, it is not economical to apply mist drilling when only a small amount of water flows into wellbore from formation during air drilling. Formation water could be circulated out of the wellbore through increasing the gas injection rate. In this paper,the Angel model was modified by introducing Nikurade friction factor for the flow in coarse open holes and translating formation water rate into equivalent penetration rate. Thus the distribution of annular pressure and the relationship between minimum air injection rate and formation water rate were obtained. Real data verification indicated that the modified model is more accurate than the Angel model and can provide useful information for air drilling.

  2. Impact of extracorporeal blood flow rate on blood pressure, pulse rate and cardiac output during haemodialysis

    DEFF Research Database (Denmark)

    Schytz, Philip Andreas; Mace, Maria Lerche; Soja, Anne Merete Boas

    2015-01-01

    BACKGROUND: If blood pressure (BP) falls during haemodialysis (HD) [intradialytic hypotension (IDH)] a common clinical practice is to reduce the extracorporeal blood flow rate (EBFR). Consequently the efficacy of the HD (Kt/V) is reduced. However, only very limited knowledge on the effect of redu...

  3. Flow rate calibration to determine cell-derived microparticles and homogeneity of blood components.

    Science.gov (United States)

    Noulsri, Egarit; Lerdwana, Surada; Kittisares, Kulvara; Palasuwan, Attakorn; Palasuwan, Duangdao

    2017-07-18

    Cell-derived microparticles (MPs) are currently of great interest to screening transfusion donors and blood components. However, the current approach to counting MPs is not affordable for routine laboratory use due to its high cost. The current study aimed to investigate the potential use of flow-rate calibration for counting MPs in whole blood, packed red blood cells (PRBCs), and platelet concentrates (PCs). The accuracy of flow-rate calibration was investigated by comparing the platelet counts of an automated counter and a flow-rate calibrator. The concentration of MPs and their origins in whole blood (n=100), PRBCs (n=100), and PCs (n=92) were determined using a FACSCalibur. The MPs' fold-changes were calculated to assess the homogeneity of the blood components. Comparing the platelet counts conducted by automated counting and flow-rate calibration showed an r(2) of 0.6 (y=0.69x+97,620). The CVs of the within-run and between-run variations of flow-rate calibration were 8.2% and 12.1%, respectively. The Bland-Altman plot showed a mean bias of -31,142platelets/μl. MP enumeration revealed both the difference in MP levels and their origins in whole blood, PRBCs, and PCs. Screening the blood components demonstrated high heterogeneity of the MP levels in PCs when compared to whole blood and PRBCs. The results of the present study suggest the accuracy and precision of flow-rate calibration for enumerating MPs. This flow-rate approach is affordable for assessing the homogeneity of MPs in blood components in routine laboratory practice. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Rate Control Protocol for Fast Flows: A Survey

    Directory of Open Access Journals (Sweden)

    Mr. Gaganpreet Singh,

    2014-01-01

    Full Text Available In today’s world, congestion control is a main objective to maximize fairness, utilization and throughput of the Internet. Every protocol has its own features to handle the congestion. The most widely used protocol over the Internet is Transfer Control Protocol. It aims at reliable and in order delivery of bytes to the higher layer and it also protect the network from congestive control. Other congestion control protocols are XCP and RCP. These new protocols are advancement over TCP. We study new congestion control protocol like Rate Control Protocol that make flows complete frequently as compared to TCP and other version of TCP and XCP. In this paper we have presented a comparison between TCP, XCP and RCP, which shows that RCP is a superior choice to use over the Internet to make flows complete quickly

  5. The wall shear rate in non-Newtonian turbulent pipe flow

    CERN Document Server

    Trinh, K T

    2010-01-01

    This paper presents a method for calculating the wall shear rate in pipe turbulent flow. It collapses adequately the data measured in laminar flow and turbulent flow into a single flow curve and gives the basis for the design of turbulent flow viscometers. Key words: non-Newtonian, wall shear rate, turbulent, rheometer

  6. Design and optimization of a large flow rate booster pump in SWRO energy recovery system

    Science.gov (United States)

    Lai, Z. N.; Wu, P.; Wu, D. Z.; Wang, L. Q.

    2013-12-01

    Seawater reverse osmosis (SWRO) is a high energy-consumption industry, so energy efficiency is an important issue. Energy recovery systems, which contain a pressure exchanger and a booster pump, are widely used in SWRO plants. As a key part of energy recovery system, the difficulty of designing booster pumps lies in high inlet pressure, high medium causticity and large flow rate. High inlet pressure adds difficulties to seal design, and large flow rate and high efficiency requirement bring high demand for hydraulic design. In this paper, a 625 m3/h booster pump is designed and optimized according to the CFD (Computational Fluid Dynamics) simulation results. The impeller and volute is well designed, a new type of high pressure mechanical seal is applied and axial force is well balanced. After optimization based on blade redesign, the efficiency of the pump was improved. The best efficiency reaches more than 85% at design point according to the CFD simulation result.

  7. Mercury flow experiments. 4th report Measurements of erosion rate caused by mercury flow

    CERN Document Server

    Kinoshita, H; Hino, R; Kaminaga, M

    2002-01-01

    The Japan Atomic Energy Research Institute (JAERI) and the High Energy Accelerator Research Organization (KEK) are promoting a construction plan of the Material-Life Science Facility, which is consisted of a Muon Science Facility and a Neutron Scattering Facility, in order to open up the new science fields. The Neutron Scattering Facility will be utilized for advanced fields of Material and Life science using high intensity neutron generated by the spallation reaction of a 1 MW pulsed proton beam and mercury target. Design of the spallation mercury target system aims to obtain high neutron performance with high reliability and safety. Since the target system is using mercury as the target material and contains large amount of radioactive spallation products, it is necessary to estimate reliability for strength of instruments in a mercury flow system during lifetime of the facility. Piping and components in the mercury flow system would be damaged by erosion with mercury flow, since these components will be we...

  8. Effect of water flow rate and feed training on "pacamã" (Siluriforme: Pseudopimelodidae juvenile production

    Directory of Open Access Journals (Sweden)

    R.K. Luz

    2011-08-01

    Full Text Available The effects of different water flow rates and feed training on the production of "pacamã" Lophiosilurus alexandri juveniles were evaluated. In the first experiment, nine day post-hatch larvae (n= 2,400 were stocked at a density of 5 larvae/L. Different water flow (F rates were tested: F1 = 180; F2 = 600; F3 = 1,300; and F4 = 2,600mL/min. Artemia nauplii were offered as food during the first 15 days of active feeding. In the second experiment for feed training, 720 juveniles (total length of 22.2mm were stocked at a density of 1.5 juveniles/L. A water flow rate similar to F1 was used. The use of extruded dry diet was tested, and feed training was done with and without other enhanced flavors (Artemia nauplii or Scott emulsion. The water flow rates did not influence the survival or growth of L. alexandri. Cannibalism occurred during feed training. The worst survival, specific growth rate and high mortality were found with the use of extruded dry diet, while similar values were registered with the different feed training diets used. Reduced water flow rate can be used to lower water consumption during larviculture and feed training of L. alexandri.

  9. High burn rate solid composite propellants

    Science.gov (United States)

    Manship, Timothy D.

    High burn rate propellants help maintain high levels of thrust without requiring complex, high surface area grain geometries. Utilizing high burn rate propellants allows for simplified grain geometries that not only make production of the grains easier, but the simplified grains tend to have better mechanical strength, which is important in missiles undergoing high-g accelerations. Additionally, high burn rate propellants allow for a higher volumetric loading which reduces the overall missile's size and weight. The purpose of this study is to present methods of achieving a high burn rate propellant and to develop a composite propellant formulation that burns at 1.5 inches per second at 1000 psia. In this study, several means of achieving a high burn rate propellant were presented. In addition, several candidate approaches were evaluated using the Kepner-Tregoe method with hydroxyl terminated polybutadiene (HTPB)-based propellants using burn rate modifiers and dicyclopentadiene (DCPD)-based propellants being selected for further evaluation. Propellants with varying levels of nano-aluminum, nano-iron oxide, FeBTA, and overall solids loading were produced using the HTPB binder and evaluated in order to determine the effect the various ingredients have on the burn rate and to find a formulation that provides the burn rate desired. Experiments were conducted to compare the burn rates of propellants using the binders HTPB and DCPD. The DCPD formulation matched that of the baseline HTPB mix. Finally, GAP-plasticized DCPD gumstock dogbones were attempted to be made for mechanical evaluation. Results from the study show that nano-additives have a substantial effect on propellant burn rate with nano-iron oxide having the largest influence. Of the formulations tested, the highest burn rate was a 84% solids loading mix using nano-aluminum nano-iron oxide, and ammonium perchlorate in a 3:1(20 micron: 200 micron) ratio which achieved a burn rate of 1.2 inches per second at 1000

  10. Nasal high flow oxygen therapy in patients with COPD reduces respiratory rate and tissue carbon dioxide while increasing tidal and end-expiratory lung volumes: a randomised crossover trial.

    Science.gov (United States)

    Fraser, John F; Spooner, Amy J; Dunster, Kimble R; Anstey, Chris M; Corley, Amanda

    2016-08-01

    Patients with COPD using long-term oxygen therapy (LTOT) over 15 h per day have improved outcomes. As inhalation of dry cold gas is detrimental to mucociliary clearance, humidified nasal high flow (NHF) oxygen may reduce frequency of exacerbations, while improving lung function and quality of life in this cohort. In this randomised crossover study, we assessed short-term physiological responses to NHF therapy in 30 males chronically treated with LTOT. LTOT (2-4 L/min) through nasal cannula was compared with NHF at 30 L/min from an AIRVO through an Optiflow nasal interface with entrained supplemental oxygen. Comparing NHF with LTOT: transcutaneous carbon dioxide (TcCO2) (43.3 vs 46.7 mm Hg, ptranscutaneous oxygen (TcO2) (97.1 vs 101.2 mm Hg, p=0.01), I:E ratio (0.75 vs 0.86, p=0.02) and respiratory rate (RR) (15.4 vs 19.2 bpm, p<0.001) were lower; and tidal volume (Vt) (0.50 vs 0.40, p=0.003) and end-expiratory lung volume (EELV) (174% vs 113%, p<0.001) were higher. EELV is expressed as relative change from baseline (%Δ). Subjective dyspnoea and interface comfort favoured LTOT. NHF decreased TcCO2, I:E ratio and RR, with a concurrent increase in EELV and Vt compared with LTOT. This demonstrates a potential mechanistic rationale behind the improved outcomes observed in long-term treatment with NHF in oxygen-dependent patients. ACTRN12613000028707. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  11. THE IMPACT OF THE EXCHANGE RATE ON THE COMMERCIALS FLOWS

    Directory of Open Access Journals (Sweden)

    Mihaela IAVORSCHI

    2015-04-01

    Full Text Available The liberalization of capital movements between states and of the trade of goods and services, are one of the most important phenomena in the current world economy. The purpose of the present study, in the case of Romania, is to answer the question whether the interventions by means of the exchange rate of the national currency contributes to the fluidization and improvement of the commercial trades. The study demonstrates that the leu devaluation does not lead to a substantial increase of the exports. As a mechanism of influence of the commercials flows, the exchange rate has a short-term influence and the economy requires structural reforms, meant to stimulate the growth of the economic competitiveness.

  12. Turbulent Poiseuille & Couette flows at high Re

    Science.gov (United States)

    Lee, Myoungkyu; Moser, Robert D.

    2016-11-01

    We present the results of direct numerical simulation (DNS) of high Re turbulent Poiseuille and Couette flows. Couette flow has been simulated with a streamwise (x) domain that is 100 πδ long at Reynolds number up to Reτ 500 . In addition Poiseuille flow simulations up to Reτ 5200 were performed. In Couette flow, extremely large scale motions, which are approximately 50 πδ long in the x-direction with very strong intensity, have been observed. In this presentation we will focus on a comparison between these two flows in terms of the vorticity-velocity co-spectra, which are interesting because of the relationship between the Reynolds stress and the velocity-vorticity correlation (∂y = - ). Also considered will be the spectra of the turbulent transport term in the evolution equation for the turbulent kinetic energy. In both (co)-spectra it is shown that the difference between the two flows at high Re are primarily at large scales. This work was supported by NSF (OCI-0749223 and PRAC Grant 0832634), and computation resources were provided by the Argonne Leadership Computing Facility through the Early Science, INCITE 2013 and Directors Discretionary Programs.

  13. Chaotic behaviour of high Mach number flows

    Science.gov (United States)

    Varvoglis, H.; Ghosh, S.

    1985-01-01

    The stability of the super-Alfvenic flow of a two-fluid plasma model with respect to the Mach number and the angle between the flow direction and the magnetic field is investigated. It is found that, in general, a large scale chaotic region develops around the initial equilibrium of the laminar flow when the Mach number exceeds a certain threshold value. After reaching a maximum the size of this region begins shrinking and goes to zero as the Mach number tends to infinity. As a result high Mach number flows in time independent astrophysical plasmas may lead to the formation of 'quasi-shocks' in the presence of little or no dissipation.

  14. Molecule-based approach for computing chemical-reaction rates in upper atmosphere hypersonic flows.

    Energy Technology Data Exchange (ETDEWEB)

    Gallis, Michail A.; Bond, Ryan Bomar; Torczynski, John Robert

    2009-08-01

    This report summarizes the work completed during FY2009 for the LDRD project 09-1332 'Molecule-Based Approach for Computing Chemical-Reaction Rates in Upper-Atmosphere Hypersonic Flows'. The goal of this project was to apply a recently proposed approach for the Direct Simulation Monte Carlo (DSMC) method to calculate chemical-reaction rates for high-temperature atmospheric species. The new DSMC model reproduces measured equilibrium reaction rates without using any macroscopic reaction-rate information. Since it uses only molecular properties, the new model is inherently able to predict reaction rates for arbitrary nonequilibrium conditions. DSMC non-equilibrium reaction rates are compared to Park's phenomenological non-equilibrium reaction-rate model, the predominant model for hypersonic-flow-field calculations. For near-equilibrium conditions, Park's model is in good agreement with the DSMC-calculated reaction rates. For far-from-equilibrium conditions, corresponding to a typical shock layer, the difference between the two models can exceed 10 orders of magnitude. The DSMC predictions are also found to be in very good agreement with measured and calculated non-equilibrium reaction rates. Extensions of the model to reactions typically found in combustion flows and ionizing reactions are also found to be in very good agreement with available measurements, offering strong evidence that this is a viable and reliable technique to predict chemical reaction rates.

  15. High-Rate Receiver Design Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose an initial architectural and preliminary hardware design study for a high-rate receiver capable of decoding modulation suites specified by CCSDS 413.0-G-1...

  16. Evaluation of Bubbler Irrigation System at Different Emission Flow Rates for Young Mango Orchard

    Directory of Open Access Journals (Sweden)

    Rajesh Kumar Soothar

    2016-08-01

    Full Text Available An experiment was conducted on evaluating performance of bubbler irrigation system under young mango plant rows at the Higher Education Commission, research station at Sindh Agriculture University, Tandojam. The experimental station possesses more than 70 mango plants, irrigated by micro and traditional irrigation methods fed by tubewell with average water static level of 9 ft below ground surface. Bubbler irrigation system was designed to irrigate 12 mango plants. The aim of study was to assess the performance of the bubbler irrigation system at different emission flow rates with an installed bubbler irrigation system to improve water distribution uniformity. The result of this study showed that the high pressure losses and the system operated on one gallon per minute flow rate of each bubbler, water distribution uniformity was low, with an average of 68 %. Other hand, comparison with emission (bubbler flow rate was adjusted at half gallon per minute has shown high water emission uniformity of system performed with an average of 92 % distribution uniformity. The reasons for the minimum distribution uniformity of bubblers were observed at one gallon per minute emission flow and this study recommended to improve the bubbler irrigation at dissimilar flow rates.

  17. Simulating High Reynolds Number Flow by Lattice Boltzmann Method

    Institute of Scientific and Technical Information of China (English)

    KANG Xiu-Ying; LIU Da-He; ZHOU Jing; JIN Yong-Juan

    2005-01-01

    @@ A two-dimensional channel flow with different Reynolds numbers is tested by using the lattice Boltzmann method under different pressure and velocity boundary conditions. The results show that the simulation error increases,and the pressure and the flow rate become unstable under a high Reynolds number. To improve the simulation precision under a high Reynolds number, the number of fluid nodes should be enlarged. For a higher Reynoldsnumber flow, the velocity boundary with an approximately parabolic velocity profile is found to be more adaptive.Blood flow in an artery with cosine shape symmetrical narrowing is then simulated under a velocity boundary condition. Its velocity, pressure and wall shear stress distributions are consistent with previous studies.

  18. Carbon film deposition from high velocity rarefied flow

    Energy Technology Data Exchange (ETDEWEB)

    Rebrov, A.K., E-mail: rebrov@itp.nsc.ru; Emelyanov, A.A.; Yudin, I.B.

    2015-01-30

    The presented study is based on the idea of the activation of a gas-precursor high velocity flow by hot wire. The wire forms the channel for flow before expansion to substrate. The construction allows change of the specific flow rate, velocity, composition and temperature of a gas mixture by studying the film synthesis in conditions from free molecular to continuum flow at velocities from hundreds to thousands of m/s. At a high pressure, the film has typical and unusual hexagonal incorporations for diamond tetragonal particles. Raman spectrum with the pronounced diamond peak is typical for diamond-like film. X-ray diffraction points in the presence of lonsdaleite. Conditions of deposition were simulated by Monte Carlo method. Collisions with hot surfaces and chemical transformations were taken into consideration as well.

  19. Model for charge/discharge-rate-dependent plastic flow in amorphous battery materials

    Science.gov (United States)

    Khosrownejad, S. M.; Curtin, W. A.

    2016-09-01

    Plastic flow is an important mechanism for relaxing stresses that develop due to swelling/shrinkage during charging/discharging of battery materials. Amorphous high-storage-capacity Li-Si has lower flow stresses than crystalline materials but there is evidence that the plastic flow stress depends on the conditions of charging and discharging, indicating important non-equilibrium aspects to the flow behavior. Here, a mechanistically-based constitutive model for rate-dependent plastic flow in amorphous materials, such as LixSi alloys, during charging and discharging is developed based on two physical concepts: (i) excess energy is stored in the material during electrochemical charging and discharging due to the inability of the amorphous material to fully relax during the charging/discharging process and (ii) this excess energy reduces the barriers for plastic flow processes and thus reduces the applied stresses necessary to cause plastic flow. The plastic flow stress is thus a competition between the time scales of charging/discharging and the time scales of glassy relaxation. The two concepts, as well as other aspects of the model, are validated using molecular simulations on a model Li-Si system. The model is applied to examine the plastic flow behavior of typical specimen geometries due to combined charging/discharging and stress history, and the results generally rationalize experimental observations.

  20. International Portfolio Flows and Exchange Rate Volatility for Emerging Markets

    OpenAIRE

    Caporale, Guglielmo Maria; Ali, Faek Menla; Spagnolo, Fabio; Spagnolo, Nicola

    2015-01-01

    This paper investigates the effects of equity and bond portfolio inflows on exchange rate volatility, using monthly bilateral data for the US vis-a-vis eight Asian developing and emerging countries (India, Indonesia, South Korea, Pakistan, Hong Kong, Thailand, the Philippines, and Taiwan) over the period 1993:01-2012:11, and estimating a time-varying transition probability Markov-switching model. We find that net equity (bond) inflows drive the exchange rate to a high (low) volatility state. ...

  1. Energy dissipation rate limits for flow through rough channels and tidal flow across topography

    CERN Document Server

    Kerswell, R R

    2016-01-01

    An upper bound on the energy dissipation rate per unit mass, $\\epsilon$, for pressure-driven flow through a channel with rough walls is derived for the first time. For large Reynolds numbers, $Re$, the bound - $\\epsilon \\,\\leq \\, c\\, U^3/h$ where $U$ is the mean flow through the channel, $h$ the channel height and $c$ a numerical prefactor - is independent of $Re$ (i.e. the viscosity) as in the smooth channel case but the numerical prefactor $c$, which is only a function of the surface heights and surface gradients (i.e. not higher derivatives), is increased. Crucially, this new bound captures the correct scaling law of what is observed in rough pipes and demonstrates that while a smooth pipe is a singular limit of the Navier-Stokes equations (data suggests $\\epsilon \\, \\sim \\, 1/(\\log Re)^2\\, U^3/h$ as $Re \\rightarrow \\infty$), it is a regular limit for current bounding techniques. As an application, the bound is extended to oscillatory flow to estimate the energy dissipation rate for tidal flow across botto...

  2. Development of digital flow control system for multi-channel variable-rate sprayers

    Science.gov (United States)

    Precision modulation of nozzle flow rates is a critical step for variable-rate spray applications in orchards and ornamental nurseries. An automatic flow rate control system activated with microprocessors and pulse width modulation (PWM) controlled solenoid valves was developed to control flow rates...

  3. Variability in venom volume, flow rate and duration in defensive stings of five scorpion species.

    Science.gov (United States)

    van der Meijden, Arie; Coelho, Pedro; Rasko, Mykola

    2015-06-15

    Scorpions have been shown to control their venom usage in defensive encounters, depending on the perceived threat. Potentially, the venom amount that is injected could be controlled by reducing the flow speed, the flow duration, or both. We here investigated these variables by allowing scorpions to sting into an oil-filled chamber, and recording the accreting venom droplets with high-speed video. The size of the spherical droplets on the video can then be used to calculate their volume. We recorded defensive stings of 20 specimens representing 5 species. Significant differences in the flow rate and total expelled volume were found between species. These differences are likely due to differences in overall size between the species. Large variation in both venom flow speed and duration are described between stinging events of single individuals. Both venom flow rate and flow duration correlate highly with the total expelled volume, indicating that scorpions may control both variables in order to achieve a desired end volume of venom during a sting.

  4. Copepod feeding currents : flow patterns, filtration rates and energetics

    NARCIS (Netherlands)

    van Duren, LA; Stamhuis, EJ; Videler, JJ

    2003-01-01

    Particle image velocimetry was used to construct a quasi 3-dimensional image of the flow generated by the feeding appendages of the calanoid copepod Temora longicornis. By scanning layers of flow, detailed information was obtained on flow velocity and velocity gradients. The flow around feeding T. l

  5. High rate fabrication of compression molded components

    Energy Technology Data Exchange (ETDEWEB)

    Matsen, Marc R.; Negley, Mark A.; Dykstra, William C.; Smith, Glen L.; Miller, Robert J.

    2016-04-19

    A method for fabricating a thermoplastic composite component comprises inductively heating a thermoplastic pre-form with a first induction coil by inducing current to flow in susceptor wires disposed throughout the pre-form, inductively heating smart susceptors in a molding tool to a leveling temperature with a second induction coil by applying a high-strength magnetic field having a magnetic flux that passes through surfaces of the smart susceptors, shaping the magnetic flux that passes through surfaces of the smart susceptors to flow substantially parallel to a molding surface of the smart susceptors, placing the heated pre-form between the heated smart susceptors; and applying molding pressure to the pre-form to form the composite component.

  6. Nanoparticle transport in water-unsaturated porous media: effects of solution ionic strength and flow rate

    Science.gov (United States)

    Prédélus, Dieuseul; Lassabatere, Laurent; Louis, Cédric; Gehan, Hélène; Brichart, Thomas; Winiarski, Thierry; Angulo-Jaramillo, Rafael

    2017-03-01

    This paper presents the influence of ionic strength and flow on nanoparticle (NP) retention rate in an unsaturated calcareous medium, originating from a heterogeneous glaciofluvial deposit of the region of Lyon (France). Laboratory columns 10 cm in diameter and 30 cm in length were used. Silica nanoparticles (Au-SiO2-FluoNPs), with hydrodynamic diameter ranging from 50 to 60 nm and labeled with fluorescein derivatives, were used to simulate particle transport, and bromide was used to characterize flow. Three flow rates and five different ionic strengths were tested. The transfer model based on fractionation of water into mobile and immobile fractions was coupled with the attachment/detachment model to fit NPs breakthrough curves. The results show that increasing flow velocity induces a decrease in nanoparticle retention, probably as the result of several physical but also geochemical factors. The results show that NPs retention increases with ionic strength. However, an inversion of retention occurs for ionic strength >5.10-2 M, which has been scarcely observed in previous studies. The measure of zeta potential and DLVO calculations show that NPs may sorb on both solid-water and air-water interfaces. NPs size distribution shows the potential for nanoparticle agglomeration mostly at low pH, leading to entrapment in the soil pores. These mechanisms are highly sensitive to both hydrodynamic and geochemical conditions, which explains their high sensitivity to flow rates and ionic strength.

  7. High-rate squeezing process of bulk metallic glasses

    Science.gov (United States)

    Fan, Jitang

    2017-03-01

    High-rate squeezing process of bulk metallic glasses from a cylinder into an intact sheet achieved by impact loading is investigated. Such a large deformation is caused by plastic flow, accompanied with geometrical confinement, shear banding/slipping, thermo softening, melting and joining. Temperature rise during the high-rate squeezing process makes a main effect. The inherent mechanisms are illustrated. Like high-pressure torsion (HPT), equal channel angular pressing (ECAP) and surface mechanical attrition treatments (SMAT) for refining grain of metals, High-Rate Squeezing (HRS), as a multiple-functions technique, not only creates a new road of processing metallic glasses and other metallic alloys for developing advanced materials, but also directs a novel technology of processing, grain refining, coating, welding and so on for treating materials.

  8. Design and construction of a novel Coriolis mass flow rate meter

    NARCIS (Netherlands)

    Mehendale, Aditya; Zwikker, Rini; Jouwsma, Wybren

    2009-01-01

    The Coriolis principle for measuring flow rates has great advantages compared to other flow measurement principles, the most important being that mass flow is measured directly. Up to now the measurement of low flow rates posed a great challenge. In a joint research project, the University of Twente

  9. Design and construction of a novel Coriolis mass flow rate meter

    NARCIS (Netherlands)

    Mehendale, A.; Zwikker, Rini; Jouwsma, Wybren

    2009-01-01

    The Coriolis principle for measuring flow rates has great advantages compared to other flow measurement principles, the most important being that mass flow is measured directly. Up to now the measurement of low flow rates posed a great challenge. In a joint research project, the University of Twente

  10. Highly stable superhydrophobic surfaces under flow conditions

    Science.gov (United States)

    Lee, Moonchan; Yim, Changyong; Jeon, Sangmin

    2015-01-01

    We synthesized hydrophobic anodic aluminum oxide nanostructures with pore diameters of 35, 50, 65, and 80 nm directly on quartz crystal microresonators, and the stability of the resulting superhydrophobicity was investigated under flow conditions by measuring changes in the resonance frequency and dissipation factor. When the quartz substrates were immersed in water, their hydrophobic surfaces did not wet due to the presence of an air interlayer. The air interlayer was gradually replaced by water over time, which caused decreases in the resonance frequency (i.e., increases in mass) and increases in the dissipation factor (i.e., increases in viscous damping). Although the water contact angles of the nanostructures increased with increasing pore size, the stability of their superhydrophobicity increased with decreasing pore size under both static conditions (without flow) and dynamic conditions (with flow); this increase can be attributed to an increase in the solid surface area that interacts with the air layer above the nanopores as the pore size decreases. Further, the effects of increasing the flow rate on the stability of the superhydrophobicity were quantitatively determined.

  11. Single-pulse dynamics and flow rates of inertial micropumps

    CERN Document Server

    Govyadinov, A N; Markel, D P; Torniainen, E D

    2015-01-01

    Bubble-driven inertial pumps are a novel method of moving liquids through microchannels. We combine high-speed imaging, computational fluid dynamics (CFD) simulations and an effective one-dimensional model to study the fundamentals of inertial pumping. Single-pulse flow through 22 x 17 um2 U-shaped channels containing 4-um polystyrene tracer beads has been imaged with a high-speed camera. The results are used to calibrate the CFD and one-dimensional models to extract an effective bubble strength. Then the frequency dependence of inertial pumping is studied both experimentally and numerically. The pump efficiency is found to gradually decrease once the successive pulses start to overlap in time.

  12. Investigation of relationship between mental workload and information flow rate of accident diagnosis tasks in NPPs

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Chang Hoon

    2005-02-15

    eye movements related to the operator's blinking and fixation on Areas Of Interests (AOIs). AOIs in the simulator interface, FISA-2/WS, are defined to analyzed the eye movement data. Blink frequency, blink duration, eye closure fraction, number of fixations on AOIs, and fixation time on AOIs are analyzed as the physiological measures. The duration and the rate of blinking decrease when the mental demand of the task increases. Since visual input is unavailable during eye closure, reduced blink rates help to maintain continuous visual input when high levels of attention are required. With higher the mental workloads, the fixation time and the more the number of fixations for instrument observation both increase. Through the experiments, the relationship between the information flow rate of accident diagnosis tasks and the selected measures is investigated. Results show that the information flow rate is significantly related to the subjective measures and physiological measures. In this study, the information flow rate of diagnosis tasks is in high agreement with both subjective rating scores and eye movements parameters related to blinking and fixation on AOIs. It appears, then, that information flow rate can be an alternative as an analytic approach for measuring mental workload. By using data on the information flow rate, we can predict the mental workload required for a task without performing experiments in advance.

  13. Multiple states in highly turbulent Taylor-Couette flow

    CERN Document Server

    Huisman, Sander G; Sun, Chao; Lohse, Detlef

    2016-01-01

    The ubiquity of turbulent flows in nature and technology makes it of utmost importance to fundamentally understand turbulence. Kolmogorov's 1941 paradigm suggests that for strongly turbulent flows with many degrees of freedom and its large fluctuations, there would only be \\emph{one} turbulent state as the large fluctuations would explore the entire higher-dimensional phase space. Here we report the first conclusive evidence of multiple turbulent states for large Reynolds number $\\text{Re}=\\mathcal{O}(10^6)$ (Taylor number $\\text{Ta}=\\mathcal{O}(10^{12})$) Taylor-Couette flow in the regime of ultimate turbulence, by probing the phase space spanned by the rotation rates of the inner and outer cylinder. The manifestation of multiple turbulent states is exemplified by providing combined global torque and local velocity measurements. This result verifies the notion that bifurcations can occur in high-dimensional flows i.e. very large $\\text{Re}$) and questions Kolmogorov's paradigm.

  14. Effect of pulsed corona discharge voltage and feed gas flow rate on dissolved ozone concentration

    Energy Technology Data Exchange (ETDEWEB)

    Prasetyaningrum, A., E-mail: ajiprasetyaningrum@gmail.com; Ratnawati,; Jos, B. [Department of Chemical Engineering, Faculty of Engineering, Diponegoro University Jl. Prof. H. Soedarto Tembalang, Semarang, Central Java, Indonesia, 50276 (Indonesia)

    2015-12-29

    Ozonization is one of the methods extensively used for water purification and degradation of organic materials. Ozone (O{sub 3}) is recognized as a powerful oxidizing agent. Due to its strong oxidability and better environmental friendless, ozone increasing being used in domestic and industrial applications. Current technology in ozone production utilizes several techniques (corona discharge, ultra violet radiation and electrolysis). This experiment aimed to evaluating effect of voltage and gas flow rate on ozone production with corona discharge. The system consists of two net-type stainless steel electrode placed in a dielectric barrier. Three pulsed voltage (20, 30, 40 KV) and flow rate (5, 10, 15 L/min) were prepare for operation variable at high frequency (3.7 kHz) with AC pulsed power supply. The dissolved ozone concentration depends on the applied high-voltage level, gas flow rate and the discharge exposure duration. The ozone concentration increases with decreasing gas flow rate. Dissolved ozone concentrations greater than 200 ppm can be obtained with a minimum voltage 40 kV.

  15. GROWTH RATE DISPERSION (GRD OF THE (010 FACE OF BORAX CRYSTALS IN FLOWING SOLUTION

    Directory of Open Access Journals (Sweden)

    Suharso Suharso

    2010-06-01

    Full Text Available The growth rates of borax crystals from aqueous solutions in the (010 direction at various flow rates were measured. The observed variations of the growth rate can be represented by a normal distribution.  It was found that there is no correlation between growth rate distribution and solution flow under these experimental conditions.   Keywords: Growth rate dispersion (GRD, borax, flow rate

  16. High Strain Rate Characterisation of Composite Materials

    DEFF Research Database (Denmark)

    Eriksen, Rasmus Normann Wilken

    The high strain rate characterisation of FRP materials present the experimenter with a new set of challenges in obtaining valid experimental data. These challenges were addressed in this work with basis in classic wave theory. The stress equilibrium process for linear elastic materials, as fibre...... a linear elastic specimen to reach a state of constant strain rate before fracture. This was in contrast to ductile materials, which are widely tested with for the High-speed servohydraulic test machine. The development of the analysis and the interpretation of the results, were based on the experience...

  17. Investigation and numerical simulation of inner-flow of an axial mineflow fan under low flow rate conditions

    Institute of Scientific and Technical Information of China (English)

    LI Yi-min; ZHOU Zhong-ning

    2008-01-01

    Because of unstable properties of axial mine flow fans working under conditions of low flow rates, the safety and reli-ability of fans in their operational zone is reduced. At times, serious vibration may bring about the destruction of equipment or even jeopardize the safety of entire factories. By means of oil flow visualization techniques and numerical simulation, we have investi-gated the inner-flow of an axial mine flow fan working under low flow rate conditions. The fundamental reasons of complex flow phenomena of the inner-flow of the flow fan under these stated conditions were revealed. At the same time and in order to improve the inner-flow under conditions of low flow rates, a blade separator and air separator were designed. From our tests we found that the blade separator and air separator are two kinds efficient methods to improve the unstable working characteristics of the axial mine flow fan operating under low flow rate conditions. The effect of the improvement of the air separator is stronger than that of the blade separator.

  18. Dependence of Selected Water Quality Parameters on Flow Rates in River Profiles in the Czech Republic

    Directory of Open Access Journals (Sweden)

    Eduard Hanslík

    2016-06-01

    The results show that in the monitored profiles, there is a direct relationship with flow rate in case of N-NO3-, suspended solids and O2. Temperature shows an inverse relationship with the flow rate. Other parameters show different relationship with the flow rate in individual monitored profiles or do not show statistically significant relation.

  19. Effects of Purge-Flow Rate on Microbubble Capture in Radial Arterial-Line Filters.

    Science.gov (United States)

    Herbst, Daniel P

    2016-09-01

    The process of microbubble filtration from blood is complex and highly dependent on the forces of flow and buoyancy. To protect the patient from air emboli, arterial-line filters commonly use a micropore screen, a large volume housing with purpose-built shape, and a purge port to trap, separate, and remove circulating microbubbles. Although it has been proposed that an insufficient buoyancy force renders the purge port ineffective at removing microbubbles smaller than 500 μm, this research attempts to investigate the purge flow of an arterial-line filter to better understand the microbubble removal function in a typical radial filter design. As its primary objective, the study aims to determine the effect of purge-flow rate on bubble capture using air bolus injections from a syringe pump with 22-gauge needle and Doppler ultrasound bubble detection. The measureable bubble size generated in the test circuit ranged between 30 and 500 μm, while purge flow was varied between .1 and .5 L/min for testing. Statistical analysis of the test data was handled using a repeated measures design with significance set at p purge flows yielded higher bubble counts, but the effect of purge-flow rate on bubble capture decreased as bubble size increased. Results also showed that purge flow from the test filter was capable of capturing all bubble sizes being generated over the entire flow range tested, and confirms utility of the purge port in removing microbubbles smaller than 500 μm. By analyzing bubble counts in the purge flow of a typical radial-filter design, this study demonstrates that currently available micropore filter technology is capable of removing the size range of bubbles that commonly pass through modern pump-oxygenator systems and should continue to be considered during extracorporeal circulation as a measure to improve patient safety.

  20. High Resolution Measurement of the Glycolytic Rate

    Science.gov (United States)

    Bittner, Carla X.; Loaiza, Anitsi; Ruminot, Iván; Larenas, Valeria; Sotelo-Hitschfeld, Tamara; Gutiérrez, Robin; Córdova, Alex; Valdebenito, Rocío; Frommer, Wolf B.; Barros, L. Felipe

    2010-01-01

    The glycolytic rate is sensitive to physiological activity, hormones, stress, aging, and malignant transformation. Standard techniques to measure the glycolytic rate are based on radioactive isotopes, are not able to resolve single cells and have poor temporal resolution, limitations that hamper the study of energy metabolism in the brain and other organs. A new method is described in this article, which makes use of a recently developed FRET glucose nanosensor to measure the rate of glycolysis in single cells with high temporal resolution. Used in cultured astrocytes, the method showed for the first time that glycolysis can be activated within seconds by a combination of glutamate and K+, supporting a role for astrocytes in neurometabolic and neurovascular coupling in the brain. It was also possible to make a direct comparison of metabolism in neurons and astrocytes lying in close proximity, paving the way to a high-resolution characterization of brain energy metabolism. Single-cell glycolytic rates were also measured in fibroblasts, adipocytes, myoblasts, and tumor cells, showing higher rates for undifferentiated cells and significant metabolic heterogeneity within cell types. This method should facilitate the investigation of tissue metabolism at the single-cell level and is readily adaptable for high-throughput analysis. PMID:20890447

  1. High resolution measurement of the glycolytic rate

    Directory of Open Access Journals (Sweden)

    Carla X Bittner

    2010-09-01

    Full Text Available The glycolytic rate is sensitive to physiological activity, hormones, stress, aging and malignant transformation. Standard techniques to measure the glycolytic rate are based on radioactive isotopes, are not able to resolve single cells and have poor temporal resolution, limitations that hamper the study of energy metabolism in the brain and other organs. A new method is described in this article, which makes use of a recently-developed FRET glucose nanosensor to measure the rate of glycolysis in single cells with high temporal resolution. Used in cultured astrocytes, the method showed for the first time that glycolysis can be activated within seconds by a combination of glutamate and K+, supporting a role for astrocytes in neurometabolic and neurovascular coupling in the brain. It was also possible to make a direct comparison of metabolism in neurons and astrocytes lying in close proximity, paving the way to a high-resolution characterization of brain energy metabolism. Single-cell glycolytic rates were also measured in fibroblasts, adipocytes, myoblasts and tumor cells, showing higher rates for undifferentiated cells and significant metabolic heterogeneity within cell types. This method should facilitate the investigation of tissue metabolism at the single-cell level and is readily adaptable for high-throughput analysis.

  2. High rate, high reliability Li/SO2 cells

    Science.gov (United States)

    Chireau, R.

    1982-03-01

    The use of the lithium/sulfur dioxide system for aerospace applications is discussed. The high rate density in the system is compared to some primary systems: mercury zinc, silver zinc, and magnesium oxide. Estimates are provided of the storage life and shelf life of typical lithium sulfur batteries. The design of lithium cells is presented and criteria are given for improving the output of cells in order to achieve high rate and high reliability.

  3. Determination of flow rates of oil, water and gas in pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Roach, G.J.; Watt, J.S.; Zastawny, H.W. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lucas Heights, NSW (Australia). Div. of Mineral Physics

    1993-12-31

    This paper describes a multiphase flow meter developed by CSIRO for determining of the flow rates of oil, water and gas in high pressure pipelines, and the results of a trial of this flow meter on an offshore oil platform. Two gamma-ray transmission gauges are mounted about a pipeline carrying the full flow of oil, water and gas. The flow rates are determined by combining single energy gamma-ray transmission measurements which determine the mass per unit area of fluids in the gamma-ray beam as a function of time, dual energy gamma-ray transmission (DUET) which determine the approximate mass fraction of oil in the liquids, cross-correlation of gamma-ray transmission measurements, with one gauge upstream of the other, which determines flow velocity, pressure and temperature measurements, and knowledge of the specific gravities of oil and (salt) water, and solubility of the gas in the liquids, all as a function of pressure and temperature. 3 figs.

  4. Accuracy of flow convergence estimates of mitral regurgitant flow rates obtained by use of multiple color flow Doppler M-mode aliasing boundaries: an experimental animal study.

    Science.gov (United States)

    Zhang, J; Jones, M; Shandas, R; Valdes-Cruz, L M; Murillo, A; Yamada, I; Kang, S U; Weintraub, R G; Shiota, T; Sahn, D J

    1993-02-01

    The proximal flow convergence method of multiplying color Doppler aliasing velocity by flow convergence surface area has yielded a new means of quantifying flow rate by noninvasively derived measurements. Unlike previous methods of visualizing the turbulent jet of mitral regurgitation on color flow Doppler mapping, flow convergence methods are less influenced by machine factors because of the systematic structure of the laminar flow convergence region. However, recent studies have demonstrated that the flow rate calculated from the first aliasing boundary of color flow Doppler imaging is dependent on orifice size, flow rate, aliasing velocity and therefore on the distance from the orifice chosen for measurement. In this study we calculated the regurgitant flow rates acquired by use of multiple proximal aliasing boundaries on color Doppler M-mode traces and assessed the effect of distances of measurement and aliasing velocities on the calculated regurgitant flow rate. Six sheep with surgically induced mitral regurgitation were studied. The distances from the mitral valve leaflet M-mode line to the first, second, and third sequential aliasing boundaries on color Doppler M-mode traces were measured and converted to the regurgitant flow rates calculated by applying the hemispheric flow equation and averaging instantaneous flow rates throughout systole. The flow rates that were calculated from the first, second, and third aliasing boundaries correlated well with the actual regurgitant flow rates (r = 0.91 to 0.96). The mean percentage error from the actual flow rates were 151% for the first aliasing boundary, 7% for the second aliasing boundary, and -43% for the third aliasing boundary; and the association between aliasing velocities and calculated flow rates indicates an inverse relationship, which suggests that in this model, there were limited velocity-distance combinations that fit with a hemispheric assumption for flow convergence geometry. The second aliasing

  5. High Rate Performing Li-ion Battery

    Science.gov (United States)

    2015-02-09

    permeable to lithium ions and efficient in transferring the electrons into/from the LVP surface to the corresponding current collector. a) b) c) d) e...PO4)3/C for High Rate Lithium-ion Battery Applications”, Lee Hwang Sheng, Nail Suleimanov, Vishwanathan Ramar, Mangayarkarasi Murugan, Kuppan

  6. [Hopes of high dose-rate radiotherapy].

    Science.gov (United States)

    Fouillade, Charles; Favaudon, Vincent; Vozenin, Marie-Catherine; Romeo, Paul-Henri; Bourhis, Jean; Verrelle, Pierre; Devauchelle, Patrick; Patriarca, Annalisa; Heinrich, Sophie; Mazal, Alejandro; Dutreix, Marie

    2017-04-01

    In this review, we present the synthesis of the newly acquired knowledge concerning high dose-rate irradiations and the hopes that these new radiotherapy modalities give rise to. The results were presented at a recent symposium on the subject. Copyright © 2017. Published by Elsevier Masson SAS.

  7. Understanding High School Graduation Rates in Arizona

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  8. Understanding High School Graduation Rates in Delaware

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  9. Understanding High School Graduation Rates in Idaho

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  10. Understanding High School Graduation Rates in Illinois

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  11. Understanding High School Graduation Rates in Massachusetts

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  12. Understanding High School Graduation Rates in Pennsylvania

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  13. Understanding High School Graduation Rates in Minnesota

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  14. Understanding High School Graduation Rates in Kentucky

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  15. Understanding High School Graduation Rates in Maryland

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  16. Understanding High School Graduation Rates in Wisconsin

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  17. Understanding High School Graduation Rates in Wyoming

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  18. Understanding High School Graduation Rates in Alaska

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  19. Understanding High School Graduation Rates in Oklahoma

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  20. Understanding High School Graduation Rates in Tennessee

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  1. Understanding High School Graduation Rates in Georgia

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  2. Understanding High School Graduation Rates in Iowa

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  3. Understanding High School Graduation Rates in Nevada

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  4. Understanding High School Graduation Rates in Texas

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  5. Understanding High School Graduation Rates in Florida

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  6. Understanding High School Graduation Rates in Nebraska

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  7. Understanding High School Graduation Rates in Oregon

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  8. Understanding High School Graduation Rates in Kansas

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  9. Understanding High School Graduation Rates in Virginia

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  10. Understanding High School Graduation Rates in Connecticut

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  11. Understanding High School Graduation Rates in Hawaii

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  12. Understanding High School Graduation Rates in Vermont

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  13. Understanding High School Graduation Rates in Mississippi

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  14. Understanding High School Graduation Rates in California

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  15. Understanding High School Graduation Rates in Ohio

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  16. Understanding High School Graduation Rates in Montana

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  17. Understanding High School Graduation Rates in Maine

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  18. Understanding High School Graduation Rates in Washington

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  19. Understanding High School Graduation Rates in Louisiana

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  20. Understanding High School Graduation Rates in Colorado

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  1. Understanding High School Graduation Rates in Michigan

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  2. Understanding High School Graduation Rates in Indiana

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  3. Understanding High School Graduation Rates in Utah

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  4. Understanding High School Graduation Rates in Alabama

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  5. Understanding High School Graduation Rates in Arkansas

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  6. Understanding High School Graduation Rates in Missouri

    Science.gov (United States)

    Alliance for Excellent Education, 2009

    2009-01-01

    Graduation rates are a fundamental indicator of whether or not the nation's public school system is doing what it is intended to do: enroll, engage, and educate youth to be productive members of society. Since almost 90 percent of the fastest-growing and highest-paying jobs require some postsecondary education, having a high school diploma and the…

  7. High speed optical holography of retinal blood flow

    CERN Document Server

    Pellizzari, Mathilde; Degardin, Julie; Sahel, Jose-Alain; Fink, Mathias; Paques, Michel; Atlan, Michael

    2016-01-01

    We performed non-invasive video imaging of retinal blood flow in a pigmented rat by holographic interferometry of near-infrared laser light backscattered by retinal tissue, beating against an off-axis reference beam sampled at a frame rate of 39 kHz with a high throughput camera. Local Doppler contrasts emerged from the envelopes of short-time Fourier transforms and the phase of autocorrelation functions of holograms rendered by Fresnel transformation. This approach permitted imaging of blood flow in large retinal vessels (30 microns diameter) over 400 by 400 pixels with a spatial resolution of 8 microns and a temporal resolution of 6.5 ms.

  8. A parallel microfluidic flow cytometer for high-content screening.

    Science.gov (United States)

    McKenna, Brian K; Evans, James G; Cheung, Man Ching; Ehrlich, Daniel J

    2011-05-01

    A parallel microfluidic cytometer (PMC) uses a high-speed scanning photomultiplier-based detector to combine low-pixel-count, one-dimensional imaging with flow cytometry. The 384 parallel flow channels of the PMC decouple count rate from signal-to-noise ratio. Using six-pixel one-dimensional images, we investigated protein localization in a yeast model for human protein misfolding diseases and demonstrated the feasibility of a nuclear-translocation assay in Chinese hamster ovary (CHO) cells expressing an NFκB-EGFP reporter.

  9. Demonstration of a high repetition rate capillary discharge waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Gonsalves, A. J., E-mail: ajgonsalves@lbl.gov; Pieronek, C.; Daniels, J.; Bulanov, S. S.; Waldron, W. L.; Mittelberger, D. E.; Leemans, W. P. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Liu, F.; Antipov, S.; Butler, J. E. [Euclid TechLabs, Gaithersburg, Maryland 20879 (United States); Bobrova, N. A.; Sasorov, P. V. [Keldysh Institute of Applied Mathematics, Moscow (Russian Federation)

    2016-01-21

    A hydrogen-filled capillary discharge waveguide operating at kHz repetition rates is presented for parameters relevant to laser plasma acceleration (LPA). The discharge current pulse was optimized for erosion mitigation with laser guiding experiments and MHD simulation. Heat flow simulations and measurements showed modest temperature rise at the capillary wall due to the average heat load at kHz repetition rates with water-cooled capillaries, which is promising for applications of LPAs such as high average power radiation sources.

  10. Method and apparatus for controlling the flow rate of mercury in a flow system

    Science.gov (United States)

    Grossman, Mark W.; Speer, Richard

    1991-01-01

    A method for increasing the mercury flow rate to a photochemical mercury enrichment utilizing an entrainment system comprises the steps of passing a carrier gas over a pool of mercury maintained at a first temperature T1, wherein the carrier gas entrains mercury vapor; passing said mercury vapor entrained carrier gas to a second temperature zone T2 having temperature less than T1 to condense said entrained mercury vapor, thereby producing a saturated Hg condition in the carrier gas; and passing said saturated Hg carrier gas to said photochemical enrichment reactor.

  11. High-deposition-rate ceramics synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Allendorf, M.D.; Osterheld, T.H.; Outka, D.A. [Sandia National Laboratories, Livermore, CA (United States)] [and others

    1995-05-01

    Parallel experimental and computational investigations are conducted in this project to develop validated numerical models of ceramic synthesis processes. Experiments are conducted in the High-Temperature Materials Synthesis Laboratory in Sandia`s Combustion Research Facility. A high-temperature flow reactor that can accommodate small preforms (1-3 cm diameter) generates conditions under which deposition can be observed, with flexibility to vary both deposition temperature (up to 1500 K) and pressure (as low as 10 torr). Both mass spectrometric and laser diagnostic probes are available to provide measurements of gas-phase compositions. Experiments using surface analytical techniques are also applied to characterize important processes occuring on the deposit surface. Computational tools developed through extensive research in the combustion field are employed to simulate the chemically reacting flows present in typical industrial reactors. These include the CHEMKIN and Surface-CHEMKIN suites of codes, which permit facile development of complex reaction mechanisms and vastly simplify the implementation of multi-component transport and thermodynamics. Quantum chemistry codes are also used to estimate thermodynamic and kinetic data for species and reactions for which this information is unavailable.

  12. Observation of Oil Flow Characteristics in Rolling Piston Rotary Compressor for Reducing Oil Circulation Rate

    Science.gov (United States)

    Song, S. j.; Noh, K. Y.; Min, B. C.; Yang, J. S.; Choi, G. M.; Kim, D. J.

    2015-08-01

    The oil circulation rate (OCR) of the rolling piston rotary compressor is a significant factor which affects the performance of refrigeration system. The increase of oil discharge causes decreasing of the heat transfer efficiency in the heat exchanger, pressure drop and lack of oil in lubricate part in compressor. In this study, the internal flow of compressor was visualized to figure out the oil droplet flow characteristics. The experiments and Computational Fluid Dynamics (CFD) simulations were conducted in various frequency of compressor to observe the effect of operation frequency on oil droplet flow characteristics for reducing OCR. In situ, measurement of oil droplet diameter and velocity were conducted by using high speed image visualization and Particle Image Velocimetry (PIV). The flow paths were dominated by copper wire parts driving the motor which was inserted in compressor. In order to verify the reliability of CFD simulation, the tendency of oil flow characteristics in each flow path and the compressor operating conditions were applied in CFD simulation. For reducing OCR, the structure such as vane, disk and ring is installed in the compressor to restrict the main flow path of oil particle. The effect of additional structure for reducing OCR was evaluated using CFD simulation and the results were discussed in detail.

  13. Wake flow characteristics at high wind speed

    DEFF Research Database (Denmark)

    Aagaard Madsen, Helge; Larsen, Torben J.; Larsen, Gunner Chr.

    2016-01-01

    power. In the present study we simulate the wake flow for a row of turbines with the wind aligned with the row using a simplified approach. The velocity deficit, being a function of the thrust coefficient, is simulated based on the BEM solution for wake expansion. An axis-symmetric boundary layer...... equation model (the same as implemented in the DWM model) is subsequently used to develop the deficit down to the next turbine, and then the approach is successively repeated. Simulation results for four different spacing’s in a row with eight turbines show that there are two major flow regimes...... in the intersection region between the two flow regimes a strong variation in power and thrust occur, e.g. going from almost zero power to rated power for a wind speed change of 4m/s. Another result is that the inflow profile to the last turbine in the row at a wind speed of 16m/s for a spacing of 3D shows...

  14. A miniature high repetition rate shock tube.

    Science.gov (United States)

    Tranter, R S; Lynch, P T

    2013-09-01

    A miniature high repetition rate shock tube with excellent reproducibility has been constructed to facilitate high temperature, high pressure, gas phase experiments at facilities such as synchrotron light sources where space is limited and many experiments need to be averaged to obtain adequate signal levels. The shock tube is designed to generate reaction conditions of T > 600 K, P shock waves with predictable characteristics are created, repeatably. Two synchrotron-based experiments using this apparatus are also briefly described here, demonstrating the potential of the shock tube for research at synchrotron light sources.

  15. Intrapericardial denervation - Radial artery blood flow and heart rate responses to LBNP

    Science.gov (United States)

    Mckeever, Kenneth H.; Skidmore, Michael G.; Keil, Lanny C.; Sandler, Harold

    1990-01-01

    The effects of intrapericardial denervation on the radial artery blood flow velocity (RABFV) and heart rate (HR) responses to LBNP in rhesus monkeys were investigated by measuring the RABFV transcutaneously by a continuous-wave Doppler ultrasonic flowmeter in order to derive an index of forearm blood flow response to low (0 to -20 mm Hg) and high (0 to -60 mm Hg) ramp exposures during supine LBNP. Four of the eight subjects were subjected to efferent and afferent cardiac denervation. It was found that, during low levels of LBNP, monkeys with cardiac denervation exhibited no cardiopulmonary baroreceptor-mediated change in the RABFV or HR, unlike the intact animals, which showed steady decreases in RABFV during both high- and low-pressure protocols. It is suggested that forearm blood flow and HR responses to low-level LBNP, along with pharmacological challenge, are viable physiological tests for verifying the completeness of atrial and cardiopulmonary baroreceptor denervation.

  16. Effect of flow rate and lead/copper pipe sequence on lead release from service lines.

    Science.gov (United States)

    Cartier, Clément; Arnold, Roger B; Triantafyllidou, Simoni; Prévost, Michèle; Edwards, Marc

    2012-09-01

    A pilot experiment examined lead leaching from four representative configurations of service lines including: (1) 100% lead (Pb), (2) 100% copper (Cu), (3) 50% Pb upstream of 50% Cu, and (4) 50% Pb-downstream of 50% Cu using a range of flow rates. The cumulative mass of lead release indicated that a typical partial replacement configuration (50% lead downstream of copper) did not provide a net reduction in lead when compared to 100% lead pipe (85 mg for 50% Pb-downstream versus 83 mg for 100%-Pb) due to galvanic and deposition corrosion. The partially replaced service line configuration also had a much greater likelihood of producing water with "spikes" of lead particulates at higher flow rates, while tending to produce lower levels of lead at very low flow rates. After the first 214 days the galvanic current between copper and lead was only reduced by 34%, proving that galvanic impacts can be highly persistent even in water with optimized corrosion control by dosing of zinc orthophosphate. Finally, this experiment raises concern about the low flow rates used during some prior home sampling events, which may underestimate exposure to lead during normal water use, especially when galvanic Pb:Cu connections are present.

  17. High strain rate behaviour of polypropylene microfoams

    Science.gov (United States)

    Gómez-del Río, T.; Garrido, M. A.; Rodríguez, J.; Arencón, D.; Martínez, A. B.

    2012-08-01

    Microcellular materials such as polypropylene foams are often used in protective applications and passive safety for packaging (electronic components, aeronautical structures, food, etc.) or personal safety (helmets, knee-pads, etc.). In such applications the foams which are used are often designed to absorb the maximum energy and are generally subjected to severe loadings involving high strain rates. The manufacture process to obtain polymeric microcellular foams is based on the polymer saturation with a supercritical gas, at high temperature and pressure. This method presents several advantages over the conventional injection moulding techniques which make it industrially feasible. However, the effect of processing conditions such as blowing agent, concentration and microfoaming time and/or temperature on the microstructure of the resulting microcellular polymer (density, cell size and geometry) is not yet set up. The compressive mechanical behaviour of several microcellular polypropylene foams has been investigated over a wide range of strain rates (0.001 to 3000 s-1) in order to show the effects of the processing parameters and strain rate on the mechanical properties. High strain rate tests were performed using a Split Hopkinson Pressure Bar apparatus (SHPB). Polypropylene and polyethylene-ethylene block copolymer foams of various densities were considered.

  18. High strain rate behaviour of polypropylene microfoams

    Directory of Open Access Journals (Sweden)

    Martínez A.B.

    2012-08-01

    Full Text Available Microcellular materials such as polypropylene foams are often used in protective applications and passive safety for packaging (electronic components, aeronautical structures, food, etc. or personal safety (helmets, knee-pads, etc.. In such applications the foams which are used are often designed to absorb the maximum energy and are generally subjected to severe loadings involving high strain rates. The manufacture process to obtain polymeric microcellular foams is based on the polymer saturation with a supercritical gas, at high temperature and pressure. This method presents several advantages over the conventional injection moulding techniques which make it industrially feasible. However, the effect of processing conditions such as blowing agent, concentration and microfoaming time and/or temperature on the microstructure of the resulting microcellular polymer (density, cell size and geometry is not yet set up. The compressive mechanical behaviour of several microcellular polypropylene foams has been investigated over a wide range of strain rates (0.001 to 3000 s−1 in order to show the effects of the processing parameters and strain rate on the mechanical properties. High strain rate tests were performed using a Split Hopkinson Pressure Bar apparatus (SHPB. Polypropylene and polyethylene-ethylene block copolymer foams of various densities were considered.

  19. Grain-size-independent plastic flow at ultrahigh pressures and strain rates.

    Science.gov (United States)

    Park, H-S; Rudd, R E; Cavallo, R M; Barton, N R; Arsenlis, A; Belof, J L; Blobaum, K J M; El-dasher, B S; Florando, J N; Huntington, C M; Maddox, B R; May, M J; Plechaty, C; Prisbrey, S T; Remington, B A; Wallace, R J; Wehrenberg, C E; Wilson, M J; Comley, A J; Giraldez, E; Nikroo, A; Farrell, M; Randall, G; Gray, G T

    2015-02-13

    A basic tenet of material science is that the flow stress of a metal increases as its grain size decreases, an effect described by the Hall-Petch relation. This relation is used extensively in material design to optimize the hardness, durability, survivability, and ductility of structural metals. This Letter reports experimental results in a new regime of high pressures and strain rates that challenge this basic tenet of mechanical metallurgy. We report measurements of the plastic flow of the model body-centered-cubic metal tantalum made under conditions of high pressure (>100  GPa) and strain rate (∼10(7)  s(-1)) achieved by using the Omega laser. Under these unique plastic deformation ("flow") conditions, the effect of grain size is found to be negligible for grain sizes >0.25  μm sizes. A multiscale model of the plastic flow suggests that pressure and strain rate hardening dominate over the grain-size effects. Theoretical estimates, based on grain compatibility and geometrically necessary dislocations, corroborate this conclusion.

  20. Non-contact flow gauging for the extension and development of rating curves

    Science.gov (United States)

    Perks, Matthew; Large, Andy; Russell, Andy

    2015-04-01

    Accurate measurement of river discharge is fundamental to understanding hydrological processes, associated hazards and ecological responses within fluvial systems. Established protocols for determining river discharge are partial, predominantly invasive and logistically difficult during high flows. There is demand for new methods for accurate quantification of flow velocity under high-flow/flood conditions to in turn enable better post-event reconstruction of peak discharge. As a consequence considerable effort has been devoted to the development of innovative technologies for the representation of flow in open channels. Remotely operated fixed and mobile systems capable of providing quantitative estimates of instantaneous and time-averaged flow characteristics using non-contact methods has been a major development. Amongst the new approaches for stand-alone continuous monitoring of surface flows is Large Scale Particle Image Velocimetry (LSPIV). Here we adapt the LSPIV concept, to provide continuous discharge measurements in non-uniform channels with complex flow conditions. High Definition videos (1080p; 30fps) of the water surface are acquired at 5 minute intervals. The image is rectified to correct for perspective distortion using a new, open source tool which minimises errors resulting from oblique image capture. Naturally occurring artefacts on the water surface (e.g. bubbles, debris, etc.) are tracked with the Kanade-Lucas-Tomasi (KLT) algorithm. The data generated is in the form of a complex surface water velocity field which can be interrogated to extract a range of hydrological information such as the streamwise velocity at a cross-section of interest, or even allow the interrogation of hydrodynamic flow structures. Here we demonstrate that this approach is capable of generating river discharge data comparable to concurrent measurements made using existing, accepted technologies (e.g. ADCP). The outcome is better constraint and extension of rating curves

  1. A Rate-Based Flow Control Mechanism for AvoidingCongestion

    Institute of Scientific and Technical Information of China (English)

    张孝林; 王宇宏; 吴介一

    2002-01-01

    The rate-based flow control mechanisms for the Available Bit Rate (ABR) service are used to share the available bandwidth of a bottleneck switch connected to a bottleneck link fairly and reasonably among many competitive users, and to maintain the buffer queue length of the switch at a desired level in order to avoid congestion in Asynchronous Transfer Mode (ATM) networks. In this paper, a control theoretic approach that uses a DeadbeatResponse (DR) controller to the design of a rate-based flow control mechanism is presented.The mechanism has a simple structure and is robust in the sense that its stability is not sensitive to the change of the number of active Virtual Connections (VCs). Simulation results show that this mechanism not only ensures fair share of the bandwidth for all active VCs regardless of the number of hops they traverse but also has the advantages of fast convergence, no oscillation,and high link bandwidth utilization.

  2. Relationships between medication intake, complaints of dry mouth, salivary flow rate and composition, and the rate of tooth demineralization in situ.

    Science.gov (United States)

    Bardow, A; Nyvad, B; Nauntofte, B

    2001-05-01

    The aim of this study was to describe the relationships between the rate of tooth demineralisation and medication intake, subjective feeling of dry mouth, saliva flow, saliva composition and the salivary level of lactobacilli. The study group consisted of 28 subjects that were divided into three groups according to their unstimulated whole saliva flow rate. Group 1 had an unstimulated saliva low rate 0.30 ml/min (n=9). The rate of tooth demineralization was determined as mineral loss assessed by quantitative microradiography of human root surfaces, exposed to the oral environment for 62 days in situ. The unstimulated and stimulated saliva flow rates, pH, bicarbonate, calcium, phosphate, and protein concentrations, as well as the degree of saturation of saliva with hydroxyapatite and the saliva buffer capacity were determined. The results showed that almost all subjects developed demineralization, albeit at highly varying rates. Eighty-five percent of the subjects in group 1, 33% of the subjects in group 2, and 0% of the subjects in group 3 developed mineral loss above the mean mineral loss for all the root surfaces in this experiment. Futhermore, group 1 differed significantly from groups 2 and 3 in having a higher medication intake, a more pronounced feeling of dry mouth, lower stimulated saliva flow rate, lower stimulated bicarbonate concentration, lower unstimulated and stimulated compositional outputs (bicarbonate, calcium, phosphate, and protein), and a higher Lactobacillus level. The best explanatory variable for high mineral loss in this study was a low unstimulated saliva flow rate. In conclusion, our results suggest that an unstimulated salivary flow rate Navazesh et al. (1992), is a better indicator of increased caries risk due to impaired salivation, than the currently accepted definition of hyposalivation (unstimulated saliva flow rate < or =0.10 ml/min), which relates to the function of the salivary glands (Sreebny, 1992).

  3. Volumetric flow rate comparisons for water and product on pasteurization systems.

    Science.gov (United States)

    Schlesser, J E; Stroup, W H; McKinstry, J A

    1994-04-01

    A flow calibration tube system was assembled to determine the volumetric flow rates for water and various dairy products through a holding tube, using three different flow promotion methods. With the homogenizer, the volumetric flow rates of water and reconstituted skim milk were within 1.5% of each other. With the positive displacement pump, the flow rate for reconstituted skim milk increased compared with that for water as the pressure increased or temperature decreased. The largest increase in flow rate was at 310-kPa gauge and 20 degrees C. On a magnetic flow meter system, the volumetric flow rates of water and reconstituted skim milk were within .5% of the flow rate measured from the volume collected in a calibrated tank. The flow rate of whole milk was similar to that of skim milk on the three flow promoters evaluated. Ice milk mix increased the flow rate of the positive displacement pump, but not the homogenizer and magnetic flow meter system.

  4. Effect of warming and flow rate conditions of blood warmers on red blood cell integrity.

    Science.gov (United States)

    Poder, T G; Pruneau, D; Dorval, J; Thibault, L; Fisette, J-F; Bédard, S K; Jacques, A; Beauregard, P

    2016-11-01

    Fluid warmers are routinely used to reduce the risk of hypothermia and cardiac complications associated with the infusion of cold blood products. However, warming blood products could generate haemolysis. This study was undertaken to compare the impact of temperature of blood warmers on the per cent haemolysis of packed red blood cells (RBCs) heated at different flow rates as well as non-flow conditions. Infusion warmers used were calibrated at 41·5°C ± 0·5°C and 37·5°C ± 0·5°C. Cold RBC units stored at 4°C in AS-3 (n = 30), aged 30-39 days old, were divided into half units before being allocated under two different scenarios (i.e. infusion pump or syringe). Blood warmers were effective to warm cold RBCs to 37·5°C or 41·5°C when used in conjunction with an infusion pump at flow rate up to 600 ml/h. However, when the warmed blood was held in a syringe for various periods of time, such as may occur in neonatal transfusions, the final temperature was below the expected requirements with measurement as low as 33·1°C. Increasing the flow with an infusion pump increased haemolysis in RBCs from 0·2% to up to 2·1% at a flow rate of 600 ml/h regardless of the warming device used (P < 0·05). No relevant increase of haemolysis was observed using a syringe. The use of a blood warmer adjusted to 41·5°C is probably the best choice for reducing the risk of hypothermia for the patient without generating haemolysis. However, we should be cautious with the use of an infusion pump for RBC transfusion, particularly at high flow rates. © 2016 International Society of Blood Transfusion.

  5. HIGH HEATING RATES AFFECTS GREATLY THE INACTIVATION RATE OF ESCHERICHIA COLI

    Directory of Open Access Journals (Sweden)

    Juan Pablo Huertas

    2016-08-01

    Full Text Available Heat resistance of microorganisms can be affected by different influencing factors. Although the effect of heating rates has been scarcely explored by the scientific community, recent researches have unraveled its important effect on the thermal resistance of different species of vegetative bacteria. Typically heating rates described in the literature ranged from 1 to 20ºC/min but the impact of much higher heating rates is unclear. The aim of this research was to explore the effect of different heating rates, such as those currently achieved in the heat exchangers used in the food industry, on the heat resistance of Escherichia coli. A pilot plant tubular heat exchanger and a thermoresistometer Mastia were used for this purpose. Results showed that fast heating rates had a deep impact on the thermal resistance of E. coli. Heating rates between 20 and 50ºC/min were achieved in the heat exchanger, which were much slower than those around 20ºC/s achieved in the thermoresistometer. In all cases, these high heating rates led to higher inactivation than expected: in the heat exchanger, for all the experiments performed, when the observed inactivation had reached about seven log cycles, the predictions estimates about 1 log cycle of inactivation; in the thermoresistometer these differences between observed and predicted values were even more than ten times higher, from 4.07 log cycles observed to 0.34 predicted at a flow rate of 70 mL/min and a maximum heating rate of 14.7ºC/s. A quantification of the impact of the heating rates on the level of inactivation achieved was established. These results point out the important effect that the heating rate has on the thermal resistance of E. coli, with high heating rates resulting in an additional sensitization to heat and therefore an effective food safety strategy in terms of food processing.

  6. High Heating Rates Affect Greatly the Inactivation Rate of Escherichia coli

    Science.gov (United States)

    Huertas, Juan-Pablo; Aznar, Arantxa; Esnoz, Arturo; Fernández, Pablo S.; Iguaz, Asunción; Periago, Paula M.; Palop, Alfredo

    2016-01-01

    Heat resistance of microorganisms can be affected by different influencing factors. Although, the effect of heating rates has been scarcely explored by the scientific community, recent researches have unraveled its important effect on the thermal resistance of different species of vegetative bacteria. Typically heating rates described in the literature ranged from 1 to 20°C/min but the impact of much higher heating rates is unclear. The aim of this research was to explore the effect of different heating rates, such as those currently achieved in the heat exchangers used in the food industry, on the heat resistance of Escherichia coli. A pilot plant tubular heat exchanger and a thermoresistometer Mastia were used for this purpose. Results showed that fast heating rates had a deep impact on the thermal resistance of E. coli. Heating rates between 20 and 50°C/min were achieved in the heat exchanger, which were much slower than those around 20°C/s achieved in the thermoresistometer. In all cases, these high heating rates led to higher inactivation than expected: in the heat exchanger, for all the experiments performed, when the observed inactivation had reached about seven log cycles, the predictions estimated about 1 log cycle of inactivation; in the thermoresistometer these differences between observed and predicted values were even more than 10 times higher, from 4.07 log cycles observed to 0.34 predicted at a flow rate of 70 mL/min and a maximum heating rate of 14.7°C/s. A quantification of the impact of the heating rates on the level of inactivation achieved was established. These results point out the important effect that the heating rate has on the thermal resistance of E. coli, with high heating rates resulting in an additional sensitization to heat and therefore an effective food safety strategy in terms of food processing. PMID:27563300

  7. High strain rate characterization of polymers

    Science.gov (United States)

    Siviour, Clive R.

    2017-01-01

    This paper reviews the literature on the response of polymers to high strain rate deformation. The main focus is on the experimental techniques used to characterize this response. The paper includes a small number of examples as well as references to experimental data over a wide range of rates, which illustrate the key features of rate dependence in these materials; however this is by no means an exhaustive list. The aim of the paper is to give the reader unfamiliar with the subject an overview of the techniques available with sufficient references from which further information can be obtained. In addition to the `well established' techniques of the Hopkinson bar, Taylor Impact and Transverse impact, a discussion of the use of time-temperature superposition in interpreting and experimentally replicating high rate response is given, as is a description of new techniques in which mechanical parameters are derived by directly measuring wave propagation in specimens; these are particularly appropriate for polymers with low wave speeds. The vast topic of constitutive modelling is deliberately excluded from this review.

  8. A prototype of a high rating MRPC

    Institute of Scientific and Technical Information of China (English)

    WANG Yi; WANG Jing-Bo; YAN Qiang; LI Yuan-Jing; CHENG Jian-Ping; YUE Qian; LI Jin

    2009-01-01

    Six-gap resistive plate chamber (MRPC) prototypes with semiconductive glass electrodes (bulk resistivity~1010.cm) were studied for suitability in time-of-flight (TOF) applications at high rates. These studies were performed using a continuous electron beam of 800 MeV at IHEP and an X-ray machine. Time resolutions of about 100 ps and efficiencies larger than 90% were obtained for flux densities up to 28 kHz/cm2.

  9. Highly viscous fluid flow in a spinning and nutating cylinder

    Science.gov (United States)

    Herbert, T.

    1985-02-01

    Spin-stabilized projectiles with liquid payloads can experience a severe flight instability characterized by a rapid yaw angle growth and a simultaneous loss in spin rate. Laboratory experiments and field tests have shown that this instability originates from the internal fluid motion in the range of high viscosity. Evaluation of the experimental data and analysis of the equations for the fluid motion in a spinning and nutating cylinder suggest a theoretical approach in three major steps: (1) analysis of the steady viscous flow in an infinitely long cylinder, (2) hydrodynamic stability analysis of this basic flow, and (3) analysis of the end effects. The basic flow has been found in analytical form. At low Reynolds number, this flow agrees well with computational results for the center section of a cylinder of aspect ratio 4.3. The despin moment caused by this flow largely agrees with experimental data for a wide range of Reynolds numbers. Current work aims at the stability of this flow.

  10. Influence of mechanical rock properties and fracture healing rate on crustal fluid flow dynamics

    Science.gov (United States)

    Sachau, Till; Bons, Paul; Gomez-Rivas, Enrique; Koehn, Daniel; de Riese, Tamara

    2016-04-01

    Fluid flow in the Earth's crust is very slow over extended periods of time, during which it occurs within the connected pore space of rocks. If the fluid production rate exceeds a certain threshold, matrix permeability alone is insufficient to drain the fluid volume and fluid pressure builds up, thereby reducing the effective stress supported by the rock matrix. Hydraulic fractures form once the effective pressure exceeds the tensile strength of the rock matrix and act subsequently as highly effective fluid conduits. Once local fluid pressure is sufficiently low again, flow ceases and fractures begin to heal. Since fluid flow is controlled by the alternation of fracture permeability and matrix permeability, the flow rate in the system is strongly discontinuous and occurs in intermittent pulses. Resulting hydraulic fracture networks are largely self-organized: opening and subsequent healing of hydraulic fractures depends on the local fluid pressure and on the time-span between fluid pulses. We simulate this process with a computer model and describe the resulting dynamics statistically. Special interest is given to a) the spatially and temporally discontinuous formation and closure of fractures and fracture networks and b) the total flow rate over time. The computer model consists of a crustal-scale dual-porosity setup. Control parameters are the pressure- and time-dependent fracture healing rate, and the strength and the permeability of the intact rock. Statistical analysis involves determination of the multifractal properties and of the power spectral density of the temporal development of the total drainage rate and hydraulic fractures. References Bons, P. D. (2001). The formation of large quartz veins by rapid ascent of fluids in mobile hydrofractures. Tectonophysics, 336, 1-17. Miller, S. a., & Nur, A. (2000). Permeability as a toggle switch in fluid-controlled crustal processes. Earth and Planetary Science Letters, 183(1-2), 133-146. Sachau, T., Bons, P. D

  11. Microstructure from simulated Brownian suspension flows at large shear rate

    Science.gov (United States)

    Morris, Jeffrey F.; Katyal, Bhavana

    2002-06-01

    Pair microstructure of concentrated Brownian suspensions in simple-shear flow is studied by sampling of configurations from dynamic simulations by the Stokesian Dynamics technique. Simulated motions are three dimensional with periodic boundary conditions to mimic an infinitely extended suspension. Hydrodynamic interactions through Newtonian fluid and Brownian motion are the only physical influences upon the motion of the monodisperse hard-sphere particles. The dimensionless parameters characterizing the suspension are the particle volume fraction and Péclet number, defined, respectively, as φ=(4π/3)na3 with n the number density and a the sphere radius, and Pe=6πηγ˙a3/kT with η the fluid viscosity, γ˙ the shear rate, and kT the thermal energy. The majority of the results reported are from simulations at Pe=1000; results of simulations at Pe=1, 25, and 100 are also reported for φ=0.3 and φ=0.45. The pair structure is characterized by the pair distribution function, g(r)=P1|1(r)/n, where P1|1(r) is the conditional probability of finding a pair at a separation vector r. The structure under strong shearing exhibits an accumulation of pair probability at contact, and angular distortion (from spherical symmetry at Pe=0), with both effects increasing with Pe. Flow simulations were performed at Pe=1000 for eight volume fractions in the range 0.2⩽φ⩽0.585. For φ=0.2-0.3, the pair structure at contact, g(|r|=2)≡g(2), is found to exhibit a single region of strong correlation, g(2)≫1, at points around the axis of compression, with a particle-deficient wake in the extensional zones. A qualitative change in microstructure is observed between φ=0.3 and φ=0.37. For φ⩾0.37, the maximum g(2) lies at points in the shear plane nearly on the x axis of the bulk simple shear flow Ux=γ˙y, while at smaller φ, the maximum g(2) lies near the compressional axis; long-range string ordering is not observed. For φ=0.3 and φ=0.45, g(2)˜Pe0.7 for 1⩽Pe⩽1000, a

  12. Relationship between sperm viability as determined by flow cytometry and nonreturn rate of dairy bulls.

    Science.gov (United States)

    Christensen, Preben; Boelling, Dorothee; Pedersen, Kurt Myrup; Korsgaard, Inge Riis; Jensen, Just

    2005-01-01

    A newly developed flow cytometric method for determination of sperm concentration and viability was tested in an insemination trial with cryopreserved bull sperm to establish the relationship between sperm viability and nonreturn rates. Semen for experimental inseminations was produced from 157 young sires (114 Holstein and 43 Jersey), each contributing 4 experimental semen collections. Straws containing approximately 15 x 10(6) motile sperm before freezing were used in 118,680 experimental inseminations performed by 254 artificial insemination technicians in 6352 Danish herds. Statistical analysis based on 44,946 experimental first inseminations showed that the major part (95.4%) of variation in the 56-day nonreturn rate (NRR56) was residual. Only 0.38% of the total variation in NRR56 was due to bulls and differences between ejaculate within bull. However, bulls were preselected, and a relatively high insemination dose was used. Correlations between sperm viability as assessed by flow cytometry and NRR56 was slightly lower than observed for microscopic assessment of sperm motility. However, flow cytometry makes it possible to achieve an objective and precise determination of sperm viability. It was therefore possible to calculate the effect on NRR56 provided selection of semen is based on the flow cytometric method. Three freezing extenders were used in this experiment, but a significant difference in NRR56 was not observed. Flow cytometric results for 1 extender (Biociphos Plus) indicated poorer sperm survival during postthaw incubation compared with Triladyl extender with whole and with clarified egg yolk.

  13. High Count Rate Electron Probe Microanalysis

    Science.gov (United States)

    Geller, Joseph D.; Herrington, Charles

    2002-01-01

    Reducing the measurement uncertainty of quantitative analyses made using electron probe microanalyzers (EPMA) requires a careful study of the individual uncertainties from each definable step of the measurement. Those steps include measuring the incident electron beam current and voltage, knowing the angle between the electron beam and the sample (takeoff angle), collecting the emitted x rays from the sample, comparing the emitted x-ray flux to known standards (to determine the k-ratio) and transformation of the k-ratio to concentration using algorithms which includes, as a minimum, the atomic number, absorption, and fluorescence corrections. This paper discusses the collection and counting of the emitted x rays, which are diffracted into the gas flow or sealed proportional x-ray detectors. The representation of the uncertainty in the number of collected x rays collected reduces as the number of counts increase. The uncertainty of the collected signal is fully described by Poisson statistics. Increasing the number of x rays collected involves either counting longer or at a higher counting rate. Counting longer means the analysis time increases and may become excessive to get to the desired uncertainty. Instrument drift also becomes an issue. Counting at higher rates has its limitations, which are a function of the detector physics and the detecting electronics. Since the beginning of EPMA analysis, analog electronics have been used to amplify and discriminate the x-ray induced ionizations within the proportional counter. This paper will discuss the use of digital electronics for this purpose. These electronics are similar to that used for energy dispersive analysis of x rays with either Si(Li) or Ge(Li) detectors except that the shaping time constants are much smaller. PMID:27446749

  14. High strain rate deformation of layered nanocomposites

    Science.gov (United States)

    Lee, Jae-Hwang; Veysset, David; Singer, Jonathan P.; Retsch, Markus; Saini, Gagan; Pezeril, Thomas; Nelson, Keith A.; Thomas, Edwin L.

    2012-11-01

    Insight into the mechanical behaviour of nanomaterials under the extreme condition of very high deformation rates and to very large strains is needed to provide improved understanding for the development of new protective materials. Applications include protection against bullets for body armour, micrometeorites for satellites, and high-speed particle impact for jet engine turbine blades. Here we use a microscopic ballistic test to report the responses of periodic glassy-rubbery layered block-copolymer nanostructures to impact from hypervelocity micron-sized silica spheres. Entire deformation fields are experimentally visualized at an exceptionally high resolution (below 10 nm) and we discover how the microstructure dissipates the impact energy via layer kinking, layer compression, extreme chain conformational flattening, domain fragmentation and segmental mixing to form a liquid phase. Orientation-dependent experiments show that the dissipation can be enhanced by 30% by proper orientation of the layers.

  15. High frame-rate digital radiographic videography

    Energy Technology Data Exchange (ETDEWEB)

    King, N.S.P.; Cverna, F.H.; Albright, K.L.; Jaramillo, S.A.; Yates, G.J.; McDonald, T.E. [Los Alamos National Lab., NM (United States); Flynn, M.J.; Tashman, S. [Henry Ford Health System, Detroit, MI (United States)

    1994-09-01

    High speed x-ray imaging can be an important tool for observing internal processes in a wide range of applications. In this paper we describe preliminary implementation of a system having the eventual goal of observing the internal dynamics of bone and joint reactions during loading. Two Los Alamos National Laboratory (LANL) gated and image intensified camera systems were used to record images from an x-ray image convertor tube to demonstrate the potential of high frame-rate digital radiographic videography in the analysis of bone and joint dynamics of the human body. Preliminary experiments were done at LANL to test the systems. Initial high frame-rate imaging (from 500 to 1000 frames/s) of a swinging pendulum mounted to the face of an X-ray image convertor tube demonstrated high contrast response and baseline sensitivity. The systems were then evaluated at the Motion Analysis Laboratory of Henry Ford Health Systems Bone and Joint Center. Imaging of a 9 inch acrylic disk with embedded lead markers rotating at approximately 1000 RPM, demonstrated the system response to a high velocity/high contrast target. By gating the P-20 phosphor image from the X-ray image convertor with a second image intensifier (II) and using a 100-microsecond wide optical gate through the second II, enough prompt light decay from the x-ray image convertor phosphor had taken place to achieve reduction of most of the motion blurring. Measurement of the marker velocity was made by using video frames acquired at 500 frames/s. The data obtained from both experiments successfully demonstrated the feasibility of the technique. Several key areas for improvement are discussed along with salient test results and experiment details.

  16. 40 CFR 53.53 - Test for flow rate accuracy, regulation, measurement accuracy, and cut-off.

    Science.gov (United States)

    2010-07-01

    ... definitions. (1) Sample flow rate means the quantitative volumetric flow rate of the air stream caused by the... the flow rate cut-off test, download the archived data from the test sampler and verify that the...

  17. Novel High Rate Lithium Intercalation Cathode Materials

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Application of amorphous V2O5/carbon/neodymium oxide (Nd2O3) composite is one of ways to surmount the lower electrical conductivity of V2O5. A new type of V2O5/carbon/Nd2O3 composite was prepared by mixing vanadium oxide hydrosol, acetone, carbon and Nd2O3 powder. High rate discharge/charge property of the composite electrode was tested electrochemically. This composite with Nd2O3 added shows the improvement of not only the discharge capacity but also cycle durability discharge capacity. The rate capability of the composite cathode also increases with the addition of Nd2O3.and cycle life are probably caused by the increase in porosity of open pores and short diffusion length of the active material on the lithium-ion insertion.

  18. Interplay of Natural Organic Matter with Flow Rate and Particle Size on Colloid Transport: Experimentation, Visualization, and Modeling.

    Science.gov (United States)

    Yang, Xinyao; Zhang, Yimeng; Chen, Fangmin; Yang, Yuesuo

    2015-11-17

    The investigation on factors that affect the impact of natural organic matter (NOM) on colloid transport in complex hydraulic flow systems remains incomplete. Using our previously established approach, the interplay of flow rate and particle size on the NOM effect was quantified, using flow rates of 1 and 2 mL/min and particle sizes of 50 and 200 nm to represent small nanoparticles (1-100 nm) and large non-nano-microspheres (100-1000 nm) in the low-flow groundwater environment. Latex particles, Suwannee River humic acid (SRHA), and iron oxide-coated sand were used as model particles, NOM, and the aquifer medium, respectively. The quantitative results show NOM blocked more sites for large particles at a high flow rate: 1 μg of SRHA blocked 5.95 × 10(9) microsphere deposition sites at 2 mL/min but only 7.38 × 10(8) nanoparticle deposition sites at 1 mL/min. The particle size effect dominated over the flow rate, and the overall effect of the two is antagonistic. Granule-scale visualization of the particle packing on the NOM-presented sand surface corroborates the quantification results, revealing a more dispersed status of large particles at a high flow rate. We interpret this phenomenon as a polydispersivity effect resulting from the differential size of the particles and NOM: high flow and a high particle size enlarge the ratio of particle-blocked to NOM-blocked areas and thus the NOM blockage. To our knowledge, this is the first model-assisted quantification on the interplay of NOM, flow rate, and particle size on colloid transport. These findings are significant for nanorisk assessment and nanoremediation practices.

  19. Performance prediction and flow analysis in the vaned distributor of a pump turbine under low flow rate in pump mode

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The main goal of this work is to investigate the possible different flow patterns existing in pump turbine under off-design conditions in pump mode. Numerical simulations by solving the Navier-Stokes equation, coupled with the "SST k-ω" turbulence model, were carried out. Flow characteristics were assumed to be stalled in the appropriate region of ?ow rate levels of Q/QD=0.15–0.61. The simulation result was compared with experimental data and they showed good agreement. Consequently, velocity fields in three axial locations in stay vanes and guide vanes were analysed in details. It was shown that "jet-wake" flow pattern exists near the band, which changes little in the whole shape with flow rate increasing; to the middle location of vanes, reverse flow begins to appear on the interface between the runner and guide vanes, which will disappear gradually as the flow rate increases; massive reverse flow is captured near the crown, whose intensity will be weakened as the flow rate increases. Ultimately, it was found that the special head-flow profile can be ascribed to the special hydraulic loss characteristics of the stay vanes and guide vanes.

  20. Experimental recombination rates for highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Reinhold Schuch [Dept. of Atomic Physics, Stockholm Univ., Frescativ., Stockholm (Sweden)

    2000-01-01

    Recent studies of recombination between free electrons and highly charged ions using electron coolers of heavy-ion storage rings have produced accurate rate coefficients of interest for plasma modeling and diagnostics. Some surprises were discovered which can lead to revisions of recombination models. With bare ions one finds at low energy a strong and puzzling deviation from radiative recombination theory. Dielectronic recombination with C3+, N4+ show that jj coupling gives essential contributions to the cross section also for light ions. (author)

  1. Flow-rate fluctuations in the outpouring of grains from a two-dimensional silo.

    Science.gov (United States)

    Janda, A; Harich, R; Zuriguel, I; Maza, D; Cixous, P; Garcimartín, A

    2009-03-01

    We present experimental results obtained with a two-dimensional silo discharging under gravity through an orifice at the flat bottom. High-speed measurements provide enough time resolution to detect every single bead that goes out and this allows the measurement of the flow rate in short-time windows. Two different regimes are clearly distinguished: one for large orifices, which can be described by Gaussian fluctuations, and another for small orifices, in which extreme events appear. The frontier between those two regimes coincides with the outlet size below which jamming events are frequent. Moreover, it is shown that the power spectrum of the flow-rate oscillations is not dominated by any particular frequency.

  2. Chemical elements potentially toxic at different flow rates in the Turvo Sujo river, MG, Brazil

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Cecon

    2009-08-01

    Full Text Available Some chemical elements in small amounts are essential to life; however, in high concentrations can commit the quality of the water courses and cause damages to human health. The objective of this work was to quantify the presence of potentially toxic elements, in a section of the Turvo Sujo river in the Viçosa city during different flow rates. In this river five collection points were chosen and monitored in four different seasons. For each point, the concentrations of copper, manganese, iron, zinc, chromium, cadmium and lead were obtained. The iron and manganese concentrations were larger in summer time, due to the largest superficial drainage in this period, while the most toxic elements, such as chromium, cadmium and lead were observed in higher concentrations in the spring period corresponding to the lowest rate flow.

  3. An electronic flow control system for a variable-rate tree sprayer

    Science.gov (United States)

    Precise modulation of nozzle flow rates is a critical measure to achieve variable-rate spray applications. An electronic flow rate control system accommodating with microprocessors and pulse width modulation (PWM) controlled solenoid valves was designed to manipulate the output of spray nozzles inde...

  4. Recrystallization of High Carbon Steel during High Strain Rate

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The recrystallization of high carbon steel during high temperature and high speed rolling has been studied by analyzing the stress-strain curves and the austenite grain size.Isothermal multi-pass hot compression at high strain rate was carried out by Gleeble-2000. The austenite grain size was measured by IBAS image analysis system. The results show that static recrystallization occurred at interpass time under pre-finish rolling, and at the finish rolling stage, due to the brief interpass time, static recrystallization can not be found.

  5. Numerical investigation and thermodynamic analysis of the effect of electrolyte flow rate on performance of all vanadium redox flow batteries

    Science.gov (United States)

    Khazaeli, Ali; Vatani, Ali; Tahouni, Nassim; Panjeshahi, Mohammad Hassan

    2015-10-01

    In flow batteries, electrolyte flow rate plays a crucial role on the minimizing mass transfer polarization which is at the compensation of higher pressure drop. In this work, a two-dimensional numerical method is applied to investigate the effect of electrolyte flow rate on cell voltage, maximum depth of discharge and pressure drop a six-cell stack of VRFB. The results show that during the discharge process, increasing electrolyte flow rate can raise the voltage of each cell up to 50 mV on average. Moreover, the maximum depth of discharge dramatically increases with electrolyte flow rate. On the other hand, the pressure drop also positively correlates with electrolyte flow rate. In order to investigate all these effects simultaneously, average energy and exergy efficiencies are introduced in this study for the transient process of VRFB. These efficiencies give insight into choosing an appropriate strategy for the electrolyte flow rate. Finally, the energy efficiency of electricity storage using VRFB is investigated and compared with other energy storage systems. The results illustrate that this kind of battery has at least 61% storage efficiency based on the second law of thermodynamics, which is considerably higher than that of their counterparts.

  6. Real time mass flow rate measurement using multiple fan beam optical tomography.

    Science.gov (United States)

    Abdul Rahim, R; Leong, L C; Chan, K S; Rahiman, M H; Pang, J F

    2008-01-01

    This paper presents the implementing multiple fan beam projection technique using optical fibre sensors for a tomography system. From the dynamic experiment of solid/gas flow using plastic beads in a gravity flow rig, the designed optical fibre sensors are reliable in measuring the mass flow rate below 40% of flow. Another important matter that has been discussed is the image processing rate or IPR. Generally, the applied image reconstruction algorithms, the construction of the sensor and also the designed software are considered to be reliable and suitable to perform real-time image reconstruction and mass flow rate measurements.

  7. High deposition rate nanocrystalline silicon with enhanced homogeneity

    Energy Technology Data Exchange (ETDEWEB)

    Verkerk, Arjan; Rath, Jatindra K.; Schropp, Ruud [Section Nanophotonics-Physics of Devices, Debye Institute for Nanomaterials Science, Faculty of Science, Utrecht University, P.O. Box 80000, 3508 TA Utrecht (Netherlands)

    2010-03-15

    High rate growth of hydrogenated nanocrystalline silicon (nc-Si:H) brings additional challenges for the homogeneity in the growth direction, since the start-up effects affect a larger portion of the film, and the very high degree of depletion increases the influence of back diffusion from the inactive region into the plasma zone. It was calculated that back diffusion plays a role in the regime for high deposition rate (4.5 nm/s) via the residence time for particles in the plasma and the corresponding diffusion length for silane from outside the plasma. The stabilization time for back diffusion was derived and found to be on the order of tens of seconds. Experiment showed that the incubation layer for nc-Si:H is very thick in films deposited at a high rate compared to films deposited in a regime of lower deposition rate. The use of a hydrogen plasma start greatly reduced this incubation layer. Further control of the crystalline fraction could be achieved via slight reduction of the degree of depletion via the silane flow. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  8. Binary interactions with high accretion rates onto main sequence stars

    Science.gov (United States)

    Shiber, Sagiv; Schreier, Ron; Soker, Noam

    2016-07-01

    Energetic outflows from main sequence stars accreting mass at very high rates might account for the powering of some eruptive objects, such as merging main sequence stars, major eruptions of luminous blue variables, e.g., the Great Eruption of Eta Carinae, and other intermediate luminosity optical transients (ILOTs; red novae; red transients). These powerful outflows could potentially also supply the extra energy required in the common envelope process and in the grazing envelope evolution of binary systems. We propose that a massive outflow/jets mediated by magnetic fields might remove energy and angular momentum from the accretion disk to allow such high accretion rate flows. By examining the possible activity of the magnetic fields of accretion disks, we conclude that indeed main sequence stars might accrete mass at very high rates, up to ≈ 10-2 M ⊙ yr-1 for solar type stars, and up to ≈ 1 M ⊙ yr-1 for very massive stars. We speculate that magnetic fields amplified in such extreme conditions might lead to the formation of massive bipolar outflows that can remove most of the disk's energy and angular momentum. It is this energy and angular momentum removal that allows the very high mass accretion rate onto main sequence stars.

  9. Maximizing protein translation rate in the non-homogeneous ribosome flow model: a convex optimization approach.

    Science.gov (United States)

    Poker, Gilad; Zarai, Yoram; Margaliot, Michael; Tuller, Tamir

    2014-11-06

    Translation is an important stage in gene expression. During this stage, macro-molecules called ribosomes travel along the mRNA strand linking amino acids together in a specific order to create a functioning protein. An important question, related to many biomedical disciplines, is how to maximize protein production. Indeed, translation is known to be one of the most energy-consuming processes in the cell, and it is natural to assume that evolution shaped this process so that it maximizes the protein production rate. If this is indeed so then one can estimate various parameters of the translation machinery by solving an appropriate mathematical optimization problem. The same problem also arises in the context of synthetic biology, namely, re-engineer heterologous genes in order to maximize their translation rate in a host organism. We consider the problem of maximizing the protein production rate using a computational model for translation-elongation called the ribosome flow model (RFM). This model describes the flow of the ribosomes along an mRNA chain of length n using a set of n first-order nonlinear ordinary differential equations. It also includes n + 1 positive parameters: the ribosomal initiation rate into the mRNA chain, and n elongation rates along the chain sites. We show that the steady-state translation rate in the RFM is a strictly concave function of its parameters. This means that the problem of maximizing the translation rate under a suitable constraint always admits a unique solution, and that this solution can be determined using highly efficient algorithms for solving convex optimization problems even for large values of n. Furthermore, our analysis shows that the optimal translation rate can be computed based only on the optimal initiation rate and the elongation rate of the codons near the beginning of the ORF. We discuss some applications of the theoretical results to synthetic biology, molecular evolution, and functional genomics.

  10. Turbulent Flow past High Temperature Surfaces

    Science.gov (United States)

    Mehmedagic, Igbal; Thangam, Siva; Carlucci, Pasquale; Buckley, Liam; Carlucci, Donald

    2014-11-01

    Flow over high-temperature surfaces subject to wall heating is analyzed with applications to projectile design. In this study, computations are performed using an anisotropic Reynolds-stress model to study flow past surfaces that are subject to radiative flux. The model utilizes a phenomenological treatment of the energy spectrum and diffusivities of momentum and heat to include the effects of wall heat transfer and radiative exchange. The radiative transport is modeled using Eddington approximation including the weighted effect of nongrayness of the fluid. The time-averaged equations of motion and energy are solved using the modeled form of transport equations for the turbulence kinetic energy and the scalar form of turbulence dissipation with an efficient finite-volume algorithm. The model is applied for available test cases to validate its predictive capabilities for capturing the effects of wall heat transfer. Computational results are compared with experimental data available in the literature. Applications involving the design of projectiles are summarized. Funded in part by U.S. Army, ARDEC.

  11. High counting rate resistive-plate chamber

    Science.gov (United States)

    Peskov, V.; Anderson, D. F.; Kwan, S.

    1993-05-01

    Parallel-plate avalanche chambers (PPAC) are widely used in physics experiments because they are fast (less than 1 ns) and have very simple construction: just two parallel metallic plates or mesh electrodes. Depending on the applied voltage they may work either in spark mode or avalanche mode. The advantage of the spark mode of operation is a large signal amplitude from the chamber, the disadvantage is that there is a large dead time (msec) for the entire chamber after an event. The main advantage of the avalanche mode is high rate capability 10(exp 5) counts/mm(sup 2). A resistive-plate chamber (RPC) is similar to the PPAC in construction except that one or both of the electrodes are made from high resistivity (greater than 10(exp 10) Omega(cm) materials. In practice RPC's are usually used in the spark mode. Resistive electrodes are charged by sparks, locally reducing the actual electric field in the gap. The size of the charged surface is about 10 mm(sup 2), leaving the rest of the detector unaffected. Therefore, the rate capability of such detectors in the spark mode is considerably higher than conventional spark counters. Among the different glasses tested the best results were obtained with electron type conductive glasses, which obey Ohm's law. Most of the work with such glasses was done with high pressure parallel-plate chambers (10 atm) for time-of-flight measurements. Resistive glasses have been expensive and produced only in small quantities. Now resistive glasses are commercially available, although they are still expensive in small scale production. From the positive experience of different groups working with the resistive glasses, it was decided to review the old idea to use this glass for the RPC. This work has investigated the possibility of using the RPC at 1 atm and in the avalanche mode. This has several advantages: simplicity of construction, high rate capability, low voltage operation, and the ability to work with non-flammable gases.

  12. Changes in Peak Expiratory Flow Rate, Blood Pressure

    African Journals Online (AJOL)

    FinePrint

    2010-03-23

    Mar 23, 2010 ... (PEFR), blood pressure and pulse rate in an attempt to determine some physiological effects of ... SBP increased significantly at 4g and 6g when compared .... Decrease in heart rate associated with ... exercise performance .

  13. Nonlinear Analysis of Bedload Transport Rate of Paroxysm Debris Flow

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The evolution characteristics of bedload transport feature of paroxysm debris flow have been studied by means of both theory analysis and experimental data.The analysis based on the flume experiment data of a sand pile model as well as a large amount of field data of debris flow clearly shown that the statistical distribu- tion for the main variable of the sand pile made of non-uniform sand (according the sand pile experiment,φ≥2.55) conform to the negative power law,that means the non-uniform sand syste...

  14. Flow propagation velocity is not a simple index of diastolic function in early filling. A comparative study of early diastolic strain rate and strain rate propagation, flow and flow propagation in normal and reduced diastolic function

    Directory of Open Access Journals (Sweden)

    Skjaerpe Terje

    2003-04-01

    Full Text Available Abstract Background Strain Rate Imaging shows the filling phases of the left ventricle to consist of a wave of myocardial stretching, propagating from base to apex. The propagation velocity of the strain rate wave is reduced in delayed relaxation. This study examined the relation between the propagation velocity of strain rate in the myocardium and the propagation velocity of flow during early filling. Methods 12 normal subjects and 13 patients with treated hypertension and normal systolic function were studied. Patients and controls differed significantly in diastolic early mitral flow measurements, peak early diastolic tissue velocity and peak early diastolic strain rate, showing delayed relaxation in the patient group. There were no significant differences in EF or diastolic diameter. Results Strain rate propagation velocity was reduced in the patient group while flow propagation velocity was increased. There was a negative correlation (R = -0.57 between strain rate propagation and deceleration time of the mitral flow E-wave (R = -0.51 and between strain rate propagation and flow propagation velocity and there was a positive correlation (R = 0.67 between the ratio between peak mitral flow velocity / strain rate propagation velocity and flow propagation velocity. Conclusion The present study shows strain rate propagation to be a measure of filling time, but flow propagation to be a function of both flow velocity and strain rate propagation. Thus flow propagation is not a simple index of diastolic function in delayed relaxation.

  15. High-energy, high-rate materials processing

    Science.gov (United States)

    Marcus, H. L.; Bourell, D. L.; Eliezer, Z.; Persad, C.; Weldon, W.

    1987-12-01

    The increasingly available range of pulsed-power, high energy kinetic storage devices, such as low-inductance pulse-forming networks, compulsators, and homopolar generators, is presently considered as a basis for industrial high energy/high rate (HEHR) processing to accomplish shock hardening, drilling, rapid surface alloying and melting, welding and cutting, transformation hardening, and cladding and surface melting in metallic materials. Time-temperature-transformation concepts furnish the basis for a fundamental understanding of the potential advantages of this direct pulsed power processing. Attention is given to the HEHR processing of a refractory molybdenum alloy, a nickel-base metallic glass, tungsten, titanium aluminides, and metal-matrix composites.

  16. High spin rate magnetic controller for nanosatellites

    Science.gov (United States)

    Slavinskis, A.; Kvell, U.; Kulu, E.; Sünter, I.; Kuuste, H.; Lätt, S.; Voormansik, K.; Noorma, M.

    2014-02-01

    This paper presents a study of a high rate closed-loop spin controller that uses only electromagnetic coils as actuators. The controller is able to perform spin rate control and simultaneously align the spin axis with the Earth's inertial reference frame. It is implemented, optimised and simulated for a 1-unit CubeSat ESTCube-1 to fulfil its mission requirements: spin the satellite up to 360 deg s-1 around the z-axis and align its spin axis with the Earth's polar axis with a pointing error of less than 3°. The attitude of the satellite is determined using a magnetic field vector, a Sun vector and angular velocity. It is estimated using an Unscented Kalman Filter and controlled using three electromagnetic coils. The algorithm is tested in a simulation environment that includes models of space environment and environmental disturbances, sensor and actuator emulation, attitude estimation, and a model to simulate the time delay caused by on-board calculations. In addition to the normal operation mode, analyses of reduced satellite functionality are performed: significant errors of attitude estimation due to non-operational Sun sensors; and limited actuator functionality due to two non-operational coils. A hardware-in-the-loop test is also performed to verify on-board software.

  17. Flow Rate in the Discharge of a Two-dimensional Silo

    Science.gov (United States)

    Zuriguel, I.; Janda, A.; Garcimartín, A.; Maza, D.

    2009-06-01

    We present an experimental study of the flow rate in the discharge of a flat bottomed two-dimensional silo. The results of the flow rate dependence on the size of the orifice evidence that the Beverloo expression is not valid for small outlet sizes. This behavior is related with the properties of the flow rate which has been found to fluctuate in a gaussian like form for large orifices. On the contrary, for small orifices extreme events appear at zero flow rates causing a significant slow down of the average flow rate. These events are explained in terms of the existence of arches that block the outlet instantaneously but are unstable to permanently halt the flow.

  18. High readmission rate after heart valve surgery

    DEFF Research Database (Denmark)

    Sibilitz, K L; Berg, S K; Thygesen, Lau Caspar;

    2015-01-01

    of anxiety and depression were present in 13.6% and 13.8%, respectively (Hospital Anxiety and Depression Scale score ≥ 8). Twelve months following discharge, 483 persons (56%) were readmitted. Readmission was associated with lower self-reported health (SF-36 PCS: 46.5 vs. 43.9, and MCS 52.2 vs. 50.7). Higher...... after surgery (3.2 (1.2-8.9)) predicted mortality. CONCLUSIONS: 6-12 months after heart valve surgery the readmission rate is high and the self-reported health status is low. Readmission is associated with low self-reported health. Therefore, targeted follow-up strategies post-surgery are needed....

  19. Litter ammonia losses amplified by higher air flow rates

    Science.gov (United States)

    ABSTRACT Broiler litter utilization has largely been associated with land application as fertilizer. Reducing ammonia (NH3) released from litter enhances its fertilizer value and negates detrimental impacts to the environment. A laboratory study was conducted to quantify the effect of air flow var...

  20. Consideration of wear rates at high velocity

    Science.gov (United States)

    Hale, Chad S.

    The development of the research presented here is one in which high velocity relative sliding motion between two bodies in contact has been considered. Overall, the wear environment is truly three-dimensional. The attempt to characterize three-dimensional wear was not economically feasible because it must be analyzed at the micro-mechanical level to get results. Thus, an engineering approximation was carried out. This approximation was based on a metallographic study identifying the need to include viscoplasticity constitutive material models, coefficient of friction, relationships between the normal load and velocity, and the need to understand wave propagation. A sled test run at the Holloman High Speed Test Track (HHSTT) was considered for the determination of high velocity wear rates. In order to adequately characterize high velocity wear, it was necessary to formulate a numerical model that contained all of the physical events present. The experimental results of a VascoMax 300 maraging steel slipper sliding on an AISI 1080 steel rail during a January 2008 sled test mission were analyzed. During this rocket sled test, the slipper traveled 5,816 meters in 8.14 seconds and reached a maximum velocity of 1,530 m/s. This type of environment was never considered previously in terms of wear evaluation. Each of the features of the metallography were obtained through micro-mechanical experimental techniques. The byproduct of this analysis is that it is now possible to formulate a model that contains viscoplasticity, asperity collisions, temperature and frictional features. Based on the observations of the metallographic analysis, these necessary features have been included in the numerical model, which makes use of a time-dynamic program which follows the movement of a slipper during its experimental test run. The resulting velocity and pressure functions of time have been implemented in the explicit finite element code, ABAQUS. Two-dimensional, plane strain models

  1. Enstrophy-based proper orthogonal decomposition of flow past rotating cylinder at super-critical rotating rate

    Science.gov (United States)

    Sengupta, Tapan K.; Gullapalli, Atchyut

    2016-11-01

    Spinning cylinder rotating about its axis experiences a transverse force/lift, an account of this basic aerodynamic phenomenon is known as the Robins-Magnus effect in text books. Prandtl studied this flow by an inviscid irrotational model and postulated an upper limit of the lift experienced by the cylinder for a critical rotation rate. This non-dimensional rate is the ratio of oncoming free stream speed and the surface speed due to rotation. Prandtl predicted a maximum lift coefficient as CLmax = 4π for the critical rotation rate of two. In recent times, evidences show the violation of this upper limit, as in the experiments of Tokumaru and Dimotakis ["The lift of a cylinder executing rotary motions in a uniform flow," J. Fluid Mech. 255, 1-10 (1993)] and in the computed solution in Sengupta et al. ["Temporal flow instability for Magnus-robins effect at high rotation rates," J. Fluids Struct. 17, 941-953 (2003)]. In the latter reference, this was explained as the temporal instability affecting the flow at higher Reynolds number and rotation rates (>2). Here, we analyze the flow past a rotating cylinder at a super-critical rotation rate (=2.5) by the enstrophy-based proper orthogonal decomposition (POD) of direct simulation results. POD identifies the most energetic modes and helps flow field reconstruction by reduced number of modes. One of the motivations for the present study is to explain the shedding of puffs of vortices at low Reynolds number (Re = 60), for the high rotation rate, due to an instability originating in the vicinity of the cylinder, using the computed Navier-Stokes equation (NSE) from t = 0 to t = 300 following an impulsive start. This instability is also explained through the disturbance mechanical energy equation, which has been established earlier in Sengupta et al. ["Temporal flow instability for Magnus-robins effect at high rotation rates," J. Fluids Struct. 17, 941-953 (2003)].

  2. Gully recharge rates and debris flows: A combined numerical modeling and field-based investigation, Haida Gwaii, British Columbia

    Science.gov (United States)

    Martin, Yvonne E.; Johnson, E. A.; Chaikina, Olga

    2017-02-01

    Rainfall, snowmelt and/or other mass movements are possible triggers to initiate debris flows. In supply-limited landscapes, clastic and organic materials (together termed debris) accumulate in the gully via various geomorphic processes that occur on gully sidewalls. The conceptualization of this phenomenon has been termed the gully recharge rate, with several recent field studies measuring such rates in coastal British Columbia. In the present study, a simple numerical model is introduced to estimate debris flow volumes in Haida Gwaii, British Columbia based on debris flow recurrence intervals, gully recharge rates and factors affecting deposition of debris flow material. Debris flow volumes obtained in model runs are somewhat lower than field-based values by about half, which is a reasonable result for this exploratory study. The annual erosion rate (clastic material) for debris flows in the model run is 0.031 mm yr- 1. This value is about 0.57 × of the field-based value and is lower than the erosion rate for debris slides in Haida Gwaii of 0.1 mm yr- 1. Deposition of debris flows in the model occurs in 60% of cases due to a decrease in channel gradient, with deposition resulting from high stream junction angles being less common. Locations for initiation of debris flow deposition were situated in stream orders 3 and 4 in 60% of cases. Sensitivity analysis shows that in comparison to other model variables, recharge rate has the greatest effect on the statistics and frequency distributions of debris flow volumes and total debris flow volume (summation of all debris activity in a basin) over the study time period.

  3. High order Poisson Solver for unbounded flows

    DEFF Research Database (Denmark)

    Hejlesen, Mads Mølholm; Rasmussen, Johannes Tophøj; Chatelain, Philippe

    2015-01-01

    as regularisation we document an increased convergence rate up to tenth order. The method however, can easily be extended well beyond the tenth order. To show the full extend of the method we present the special case of a spectrally ideal regularisation of the velocity formulated integration kernel, which achieves......This paper presents a high order method for solving the unbounded Poisson equation on a regular mesh using a Green’s function solution. The high order convergence was achieved by formulating mollified integration kernels, that were derived from a filter regularisation of the solution field...... or by performing the differentiation as a multiplication of the Fourier coefficients. In this way, differential operators such as the divergence or curl of the solution field could be solved to the same high order convergence without additional computational effort. The method was applied and validated using...

  4. High-Resolution Flow Logging for Hydraulic Characterization of Boreholes and Aquifer Flow Zones at Contaminated Bedrock Sites

    Science.gov (United States)

    Williams, J. H.; Johnson, C. D.; Paillet, F. L.

    2004-05-01

    In the past, flow logging was largely restricted to the application of spinner flowmeters to determine flow-zone contributions in large-diameter production wells screened in highly transmissive aquifers. Development and refinement of tool-measurement technology, field methods, and analysis techniques has greatly extended and enhanced flow logging to include the hydraulic characterization of boreholes and aquifer flow zones at contaminated bedrock sites. State-of-the-art in flow logging will be reviewed, and its application to bedrock-contamination investigations will be presented. In open bedrock boreholes, vertical flows are measured with high-resolution flowmeters equipped with flexible rubber-disk diverters fitted to the nominal borehole diameters to concentrate flow through the measurement throat of the tools. Heat-pulse flowmeters measure flows in the range of 0.05 to 5 liters per minute, and electromagnetic flowmeters measure flows in the range of 0.3 to 30 liters per minute. Under ambient and low-rate stressed (either extraction or injection) conditions, stationary flowmeter measurements are collected in competent sections of the borehole between fracture zones identified on borehole-wall images. Continuous flow, fluid-resistivity, and temperature logs are collected under both sets of conditions while trolling with a combination electromagnetic flowmeter and fluid tool. Electromagnetic flowmeters are used with underfit diverters to measure flow rates greater than 30 liters per minute and suppress effects of diameter variations while trolling. A series of corrections are applied to the flow-log data to account for the zero-flow response, bypass, trolling, and borehole-diameter biases and effects. The flow logs are quantitatively analyzed by matching simulated flows computed with a numerical model to measured flows by varying the hydraulic properties (transmissivity and hydraulic head) of the flow zones. Several case studies will be presented that demonstrate

  5. Measurement and Modelling of Air Flow Rate in a Naturally Ventilated Double Skin Facade

    DEFF Research Database (Denmark)

    Heiselberg, Per; Kalyanova, Olena; Jensen, Rasmus Lund

    2008-01-01

    Air flow rate in a naturally ventilated double skin façade (DSF) is extremely difficult to measure due to the stochastic nature of wind, and as a consequence non-uniform and dynamic flow conditions. This paper describes the results of two different methods to measure the air flow in a full-scale ...

  6. In Vivo Three-Dimensional Velocity Vector Imaging and Volumetric Flow Rate Measurements

    DEFF Research Database (Denmark)

    Pihl, Michael Johannes; Stuart, Matthias Bo; Tomov, Borislav Gueorguiev

    2013-01-01

    scanner SARUS. Measurements are conducted on a carotid artery flow phantom from Danish Phantom Design, and 20 frames are acquired with a constant flow rate of 16.7±0.17 mL/s provided by a Shelley Medical Imaging Technologies CompuFlow 1000 system. The peak velocity magnitude in the vessel is found...

  7. Upgrade Strategy for ALICE at High Rate

    CERN Document Server

    Musa, L

    2012-01-01

    The longterm goal of the ALICE experiment is to provide a precise characterization of the Quark-Gluon Plasma (QGP) state. Such a determination of its properties including initial temperature, degrees of freedom, speed of sound, and in general, transport coefficients would be a major achievement. This would go a long way towards a better understanding of QCD as a genuine multi-particle theory. To achieve this goal, high statistics measurements are required, which will give access also to the very rare physics channels needed to understand the dynamics of this condensed phase of QCD. The general upgrade strategy for the ALICE central barrel is conceived to deal with this challenge with expected Pb-Pb interaction rates of up to 50 kHz, that would provide an accumulated sample of the order of 10 nb^-1 in the period 2019-2023. In this document we sketch the modifications/replacements needed in all ALICE central barrel detectors and online systems (Trigger, DAQ and HLT) for high luminosity running. As the ALICE for...

  8. Investigation of the effect of wall friction on the flow rate in 2D and 3D Granular Flow

    Science.gov (United States)

    Carballo-Ramirez, Brenda; Pleau, Mollie; Easwar, Nalini; Birwa, Sumit; Shah, Neil; Tewari, Shubha

    We have measured the mass flow rate of spherical steel spheres under gravity in vertical, straight-walled 2 and 3-dimensional hoppers, where the flow velocity is controlled by the opening size. Our measurements focus on the role of friction and its placement along the walls of the hopper. In the 2D case, an increase in the coefficient of static friction from μ = 0.2 to 0.6 is seen to decrease the flow rate significantly. We have changed the placement of frictional boundaries/regions from the front and back walls of the 2D hopper to the side walls and floor to investigate the relative importance of the different regions in determining the flow rate. Fits to the Beverloo equation show significant departure from the expected exponent of 1.5 in the case of 2D flow. In contrast, 3D flow rates do not show much dependence on wall friction and its placement. We compare the experimental data to numerical simulations of gravity driven hopper granular flow with varying frictional walls constructed using LAMMPS*. *http://lammps.sandia.gov Supported by NSF MRSEC DMR 0820506.

  9. Effect of wall shear rate on biofilm deposition and grazing in drinking water flow chambers.

    Science.gov (United States)

    Paris, Tony; Skali-Lami, Salaheddine; Block, Jean-Claude

    2007-08-15

    The effect of four-wall shear rates (34.9, 74.8, 142.5, and 194.5 s(-1)) on bacterial deposition on glass slides in drinking water flow chambers was studied. Biofilm image acquisition was performed over a 50-day period. Bacterial accumulation and surface coverage curves were obtained. Microscopic observations allowed us to obtain information about the dynamics and spatial distribution of the biofilm. During the first stage of biofilm formation (210-518 h), bacterial accumulation was a function of the wall shear rate: the higher the wall shear rate, the faster the bacterial deposition (1.1 and 1.9 x 10(4) bacterial cells . cm(-2) for wall shear rates of 34.9 and 142.5 s(-1), respectively). A new similarity relationship characteristic of a non-dimensional time and function of the wall shear rate was proposed to describe initial bacterial deposition. After 50 days of exposure to drinking water, surface coverage was more or less identical under the entire wall shear rates (7.44 +/- 0.9%), suggesting that biofilm bacterial density cannot be controlled using hydrodynamics. However, the spatial distribution of the biofilm was clearly different. Under low wall shear rate, aggregates were composed of bacterial cells able to "vibrate" independently on the surface, whereas, under a high wall shear rate, aggregates were more cohesive. Therefore, susceptibility to the hydraulic discontinuities occurring in drinking water system may not be similar. In all the flow chambers, significant decreases in bacterial biomass (up to 77%) were associated with the presence of amoebae. This grazing preferentially targeted small, isolated cells.

  10. High speed optical holography of retinal blood flow.

    Science.gov (United States)

    Pellizzari, M; Simonutti, M; Degardin, J; Sahel, J-A; Fink, M; Paques, M; Atlan, M

    2016-08-01

    We performed noninvasive video imaging of retinal blood flow in a pigmented rat by holographic interferometry of near-infrared laser light backscattered by retinal tissue, beating against an off-axis reference beam sampled at a frame rate of 39 kHz with a high throughput camera. Local Doppler contrasts emerged from the envelopes of short-time Fourier transforms and the phase of autocorrelation functions of holograms rendered by Fresnel transformation. This approach permitted imaging of blood flow in large retinal vessels (∼30 microns diameter) over 400×400  pixels with a spatial resolution of ∼8 microns and a temporal resolution of ∼6.5  ms.

  11. Flow Characterization of a Piezo-Electric High Speed Valve

    Directory of Open Access Journals (Sweden)

    T. Takiya

    2012-03-01

    Full Text Available Injecting a gas into fusion reactors or semiconductor manufacturing systems, one has to quickly control the flow rate by a piezoelectric valve. In order to construct a gas injection system with high speed valves in the future, performance tests have been conducted on a commercial piezoelectric valve. An orifice flowmeter for measuring time average flowrate and a hot wire anemometer for instantaneous flowrate were manufactured. The total flow coefficient of the orifice flowmeter was obtained experimentally under a low pressure of a 10-2 Pa and a low flowrate of a few mg/s, although they are smaller than the values specified by Japanese Industrial Standards. It is found that the hot wire anemometer installed downstream in the vicinity of the valve is suitable for detecting the change in flowrate with the response time of less than 1 ms.

  12. Distributed measurement of flow rate in conduits using heated fiber optic distributed temperature sensing

    Science.gov (United States)

    Sánchez, Raúl; Zubelzu, Sergio; Rodríguez-Sinobas, Leonor; Juana, Luis

    2016-04-01

    In some cases flow varies along conduits, such as in irrigated land drainage pipes and channels, irrigation laterals and others. Detailed knowledge of flow rate along the conduit makes possible analytical evaluation of water distribution and collection systems performance. Flow rate can change continuously in some systems, like in drainage pipes and channels, or abruptly, like in conduits bifurcations or emitter insertions. A heat pulse along the conduit makes possible to get flow rate from continuity and heat balance equations. Due to the great value of specific heat of water, temperature changes along conduit are smaller than the noise that involves the measurement process. This work presents a methodology that, dealing with the noise of distributed temperature measurements, leads to flow rate determination along pressurized pipes or open channel flows.

  13. Comparison of whole saliva flow rates and mucin concentrations in healthy Caucasian young and aged adults.

    Science.gov (United States)

    Navazesh, M; Mulligan, R A; Kipnis, V; Denny, P A; Denny, P C

    1992-06-01

    Unstimulated and chewing-stimulated whole saliva samples were obtained from 42 healthy Caucasians; 21 were between 18 and 35 years of age, and 21 between 65 and 83 years of age. The unstimulated salivary flow rate was significantly lower in the aged group, but the stimulated flow rate was significantly higher in the aged than in the young group. Both groups showed significantly increased flow during salivary stimulation. MG1 and MG2 concentrations in unstimulated and stimulated saliva samples were significantly lower in the aged group. There were no significant correlations between salivary flow rates and MG1 and MG2 concentrations.

  14. High-temperature zirconia microthruster with an integrated flow sensor

    Science.gov (United States)

    Lekholm, Ville; Persson, Anders; Palmer, Kristoffer; Ericson, Fredric; Thornell, Greger

    2013-05-01

    This paper describes the design, fabrication and characterization of a ceramic, heated cold-gas microthruster device made with silicon tools and high temperature co-fired ceramic processing. The device contains two opposing thrusters, each with an integrated calorimetric propellant flow sensor and a heater in the stagnation chamber of the nozzle. The exhaust from a thruster was photographed using schlieren imaging to study its behavior and search for leaks. The heater elements were tested under a cyclic thermal load and to the maximum power before failure. The nozzle heater was shown to improve the efficiency of the thruster by 6.9%, from a specific impulse of 66 to 71 s, as calculated from a decrease of the flow rate through the nozzle of 13%, from 44.9 to 39.2 sccm. The sensitivity of the integrated flow sensor was measured to 0.15 mΩ sccm-1 in the region of 0-15 sccm and to 0.04 mΩ sccm-1 above 20 sccm, with a zero-flow sensitivity of 0.27 mΩ sccm-1. The choice of yttria-stabilized zirconia as a material for the devices makes them robust and capable of surviving temperatures locally exceeding 1000 °C.

  15. Parametric expressions of tritium flow rates and inventories in a target factory

    Energy Technology Data Exchange (ETDEWEB)

    Sherohman, J.W.

    1980-12-29

    Parametric expressions have been derived for tritium flow rates and inventories in a target factory. The expressions are based on a tritium system that interfaces with a generalized target production process. The relationship of flow rates and inventories to target production form a basis for parametric study to determine the amount of tritium involved in the target factory of an ICF power plant.

  16. Impact of catheter on uroflow rate in pressure-flow study

    Institute of Scientific and Technical Information of China (English)

    张鹏; 武治津; 高居忠

    2004-01-01

    @@ The importance of a pressure-flow study in the diagnostic work-up of patients suffering from benign prostatic hyperplasia (BPH) has been recognized. However, there is still uncertainty regarding the role the catheter might play in affecting uroflow rate during a pressure-flow study. In this present study, we retrospectively analyzed voiding data from pressure-flow studies taken before and after catheterization in 44 patients suffering from BPH to investigate whether catheterization has an effect on uroflow rate.

  17. Influence of the mass flow rate of secondary air on the gas/particle flow characteristics in the near-burner region of a double swirl flow burner

    Energy Technology Data Exchange (ETDEWEB)

    Jing, J.P.; Li, Z.Q.; Wang, L.; Chen, Z.C.; Chen, L.Z.; Zhang, F.C. [Harbin Institute of Technology, Harbin (China)

    2011-06-15

    The influence of the mass flow rate of secondary air on the gas/particle flow characteristics of a double swirl flow burner, in the near-burner region, was measured by a three-component particle-dynamics anemometer, in conjunction with a gas/particle two-phase test facility. Velocities, particle volume flux profiles, and normalized particle number concentrations were obtained. The relationship between the gas/particle flows and the combustion characteristics of the burners was discussed. For different mass flow rates of secondary air, annular recirculation zones formed only in the region of r/d=0.3-0.6 at x/d=0.1-0.3. With an increasing mass flow rate of secondary air, the peaks of the root mean square (RMS) axial fluctuating velocities, radial mean velocities, RMS radial fluctuating velocities, and tangential velocities all increased, while the recirculation increased slightly. There was a low particle volume flux in the central zone of the burner. At x/d=0.1-0.7, the profiles of particle volume flux had two peaks in the secondary air flow zone near the wall. With an increasing mass flow rate of secondary air, the peak of particle volume flux in the secondary air flow zone decreased, but the peak of particle volume flux near the wall increased. In section x/d=0.1-0.5, the particle diameter in the central zone of the burner was always less than the particle diameter at other locations.

  18. High Strain Rate Compression Testing of Ceramics and Ceramic Composites.

    Energy Technology Data Exchange (ETDEWEB)

    Blumenthal, W. R. (William R.)

    2005-01-01

    The compressive deformation and failure behavior of ceramics and ceramic-metal composites for armor applications has been studied as a function of strain rate at Los Alamos National Laboratory since the late 1980s. High strain rate ({approx}10{sup 3} s{sup -1}) uniaxial compression loading can be achieved using the Kolsky-split-Hopkinson pressure bar (SHPB) technique, but special methods must be used to obtain valid strength results. This paper reviews these methods and the limitations of the Kolsky-SHPB technique for this class of materials. The Kolsky-split-Hopkinson pressure bar (Kolsky-SHPB) technique was originally developed to characterize the mechanical behavior of ductile materials such as metals and polymers where the results can be used to develop strain-rate and temperature-dependent constitutive behavior models that empirically describe macroscopic plastic flow. The flow behavior of metals and polymers is generally controlled by thermally-activated and rate-dependent dislocation motion or polymer chain motion in response to shear stresses. Conversely, the macroscopic mechanical behavior of dense, brittle, ceramic-based materials is dominated by elastic deformation terminated by rapid failure associated with the propagation of defects in the material in response to resolved tensile stresses. This behavior is usually characterized by a distribution of macroscopically measured failure strengths and strains. The basis for any strain-rate dependence observed in the failure strength must originate from rate-dependence in the damage and fracture process, since uniform, uniaxial elastic behavior is rate-independent (e.g. inertial effects on crack growth). The study of microscopic damage and fracture processes and their rate-dependence under dynamic loading conditions is a difficult experimental challenge that is not addressed in this paper. The purpose of this paper is to review the methods that have been developed at the Los Alamos National Laboratory to

  19. Surface supersaturation in flow-rate modulation epitaxy of GaN

    Science.gov (United States)

    Akasaka, Tetsuya; Lin, Chia-Hung; Yamamoto, Hideki; Kumakura, Kazuhide

    2017-06-01

    Hillocks on N-face GaN (000 1 bar) films are effectively eliminated by group-III-source flow-rate modulation epitaxy (FME), wherein the flow-rate of group-III sources are sequentially modulated under a constant supply of NH3. A hillock-free smooth surface obtained by group-III-source FME is attributed to the enhancement of step-flow growth. We found that a hillock originates from a micropipe and grows by spiral growth around the micropipe. The spiral growth rate rapidly decreases with decreasing the degree of surface supersaturation σ, while the step-flow growth rate decreases linearly. For group-III-source FME, wherein σ is lower than conventional continuous growth, the spiral growth rate could be lower than the step-flow growth one so that the formation of hillocks is suppressed.

  20. Adaptive real-time forecast of river flow-rates from rainfall data

    Science.gov (United States)

    Bolzern, P.; Ferrario, M.; Fronza, G.

    1980-07-01

    The paper describes a stochastic rainfall—river flow-rate model of the ARMAX type. Then a real-time Kalman predictor is derived from the model, namely a recursive relationship which, at the beginning of each time step, supplies the "best" forecast of future flow-rate on the basis of current rainfall and flow-rate measurements. Three different versions (ordered in the sense of increasing complexity) of the predictor are considered, corresponding to different approaches for estimating parameters and noise statistics of the stochastic model. The flood forecast performance of all predictors is tested on a real case (Lake Maggiore water system). The performance is satisfactory (for instance correlations about 99% between forecast and true values, standard deviation of the forecast error less than 1% of the average flood flow-rate) and conspicuously better than the one given by the trivial persistence predictor (the future flow-rate is the present one).

  1. DYNAMIC CHARACTERISTICS OF LARGE FLOW RATING ELECTRO-HYDRAULIC PROPORTIONAL CARTRIDGE VALVE

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A kind of cartridge servo proportional valve is discussed, which can be used for controlling large flow rate with high performance. By analyzing the structure principle of the valve, the transfer function of the valve is derived. With the transfer function, some structure elements that may affect its performance are investigated. Through the numerical simulation and test study, some principles of optimality and effective methods for improving the dynamic performance of the valve are proposed. The test results conform to the results of the theoretical analysis and simulation, which proves the correctness of the study and simulation works. The paper provides theoretical basis for engineering applications and series expanding design works.

  2. The influence of flow rate on inter-nucleation site heat transport

    Directory of Open Access Journals (Sweden)

    Baltis Coen

    2014-01-01

    Full Text Available The main topic of this paper is the influence of vertically aligned nucleation sites on each other in upward flow boiling. A setup was constructed to facilitate vertical up-flow of deminiralized water under saturation conditions. The main test section is a glass channel with a set of vertically aligned bubble generators. Each bubble generator is operated independently, where power and wall temperature are registered and the vapour bubbles are visualized by a high-speed camera. During the experiments, the downstream bubble generator (BG1 power is kept constant, while the power fed to the upstream bubble generator (BG2 is incrementally increased. Two main trends have been identified. The first trend is dominated by added convection from one site to the other. Both bubble frequency and detachment diameter on BG1 increase with increased power fed to upstream BG2. This effect decreases with increasing inter-site distance and becomes more significant with increasing liquid flow rate. When vapor bubbles start nucleating from BG2, these vapor bubbles inhibit bubble nucleation BG1 and can even lead to deactivation of this nucleation site. This second trend is only weakly dependent on inter-site distance, since the inhibition originates from bubbles flowing past BG1 in close proximity.

  3. Effect of Injection Flow Rate on Product Gas Quality in Underground Coal Gasification (UCG Based on Laboratory Scale Experiment: Development of Co-Axial UCG System

    Directory of Open Access Journals (Sweden)

    Akihiro Hamanaka

    2017-02-01

    Full Text Available Underground coal gasification (UCG is a technique to recover coal energy without mining by converting coal into a valuable gas. Model UCG experiments on a laboratory scale were carried out under a low flow rate (6~12 L/min and a high flow rate (15~30 L/min with a constant oxygen concentration. During the experiments, the coal temperature was higher and the fracturing events were more active under the high flow rate. Additionally, the gasification efficiency, which means the conversion efficiency of the gasified coal to the product gas, was 71.22% in the low flow rate and 82.42% in the high flow rate. These results suggest that the energy recovery rate with the UCG process can be improved by the increase of the reaction temperature and the promotion of the gasification area.

  4. Flow “Fine” Synthesis: High Yielding and Selective Organic Synthesis by Flow Methods

    Science.gov (United States)

    2015-01-01

    Abstract The concept of flow “fine” synthesis, that is, high yielding and selective organic synthesis by flow methods, is described. Some examples of flow “fine” synthesis of natural products and APIs are discussed. Flow methods have several advantages over batch methods in terms of environmental compatibility, efficiency, and safety. However, synthesis by flow methods is more difficult than synthesis by batch methods. Indeed, it has been considered that synthesis by flow methods can be applicable for the production of simple gasses but that it is difficult to apply to the synthesis of complex molecules such as natural products and APIs. Therefore, organic synthesis of such complex molecules has been conducted by batch methods. On the other hand, syntheses and reactions that attain high yields and high selectivities by flow methods are increasingly reported. Flow methods are leading candidates for the next generation of manufacturing methods that can mitigate environmental concerns toward sustainable society. PMID:26337828

  5. Low flow and high flow responses to converting natural grassland into bluegum ( Eucalyptus globulus) in Nilgiris watersheds of South India

    Science.gov (United States)

    Sikka, A. K.; Samra, J. S.; Sharda, V. N.; Samraj, P.; Lakshmanan, V.

    2003-01-01

    A concern has been raised in many parts of the world over the effect of large scale planting of Eucalyptus on hydrological behaviour of small watersheds. Hydrological response of watersheds due to conversion of natural grasslands into bluegum ( Eucalyptus globulus) plantations on low flows and high flows has been presented in this paper. The concept of using low flow index (LFI) as a tool to study and quantify the effects of bluegum plantation on low flow regime has been demonstrated. Conversion of natural grasslands into bluegum plantations has resulted in decreased low flow volume as well as peak flow, which in turn increased the soil moisture losses. These effects were more pronounced during the second rotation (i.e. first coppiced growth) as compared to the first rotation. Significant reduction in low flow as a result of decline in base flow could be predicted with LFI decreasing by 2.0 and 3.75 times, in the first and second rotation, respectively. Moderation in peak discharge rates was also observed as a result of bluegum plantation. Probability plots of peak discharge tend to suggest that the effect of bluegum plantation on peak flows become insignificant for the floods with higher return periods. These results clearly suggest that caution need to be exercised while planning large scale conversion of natural grasslands into bluegum plantations in the catchments of hydro-electric reservoirs in the Nilgiris which adversely affects water availability especially during lean flow period.

  6. Effect of the flow composition on outflow rates from accretion discs around black holes

    CERN Document Server

    Kumar, Rajiv; Chattopadhyay, Indranil; Chakrabarti, Sandip K

    2013-01-01

    We studied the outflow behaviour from accretion discs around black holes taking into account the vertical equilibrium accretion flow model. The outflow rate is found to depend crucially on flow composition. Our approach is to study the outflow behaviour as function of inflow around black holes with an equation of state which allows flow to be thermally relativistic close to black holes and non relativistic far away from black holes. We studied shock ejection model. A pure electron positron pair flow never undergoes shock transition while presence of some baryons (common in outflows and jets) makes it possible to have standing shock waves in the flow. It can be concluded that the presence of protons is necessary for the flow to show the outflow behaviour. The outflow rate is maximum when the flow contains the proton number density which is 27% of the electron number density. We conclude that a pure electron-positron jet is unlikely to form.

  7. High voltage high repetition rate pulse using Marx topology

    Science.gov (United States)

    Hakki, A.; Kashapov, N.

    2015-06-01

    The paper describes Marx topology using MOSFET transistors. Marx circuit with 10 stages has been done, to obtain pulses about 5.5KV amplitude, and the width of the pulses was about 30μsec with a high repetition rate (PPS > 100), Vdc = 535VDC is the input voltage for supplying the Marx circuit. Two Ferrite ring core transformers were used to control the MOSFET transistors of the Marx circuit (the first transformer to control the charging MOSFET transistors, the second transformer to control the discharging MOSFET transistors).

  8. Influence of riparian vegetation on near-bank flow structure and erosion rates on a large meandering river

    Science.gov (United States)

    Konsoer, K. M.; Rhoads, B. L.; Langendoen, E. J.; Johnson, K.; Ursic, M.

    2012-12-01

    Rates of meander migration are dependent upon dynamic interactions between planform geometry, three-dimensional flow structure, sediment transport, and the erodibility and geotechnical properties of the channel banks and floodplains. Riparian vegetation can greatly reduce the rate of migration through root-reinforcement and increased flow resistance near the bank. In particular, forested riverbanks can also provide large woody debris (LWD) to the channel, and if located near the outer bank, can act to amour the bank by disrupting three-dimensional flow patterns and redirecting flow away from the bank-toe, the locus of erosion in meandering rivers. In this paper, three-dimensional flow patterns and migration rates are compared for two meander bends, one forested and one non-forested, on the Wabash River, near Grayville, Illinois. Flow data were obtained using acoustic Doppler current profilers (ADCP) for two large flow events in May and June 2011. LWD was mapped using a terrestrial LiDAR survey, and residence times for the LWD were estimated by comparing the survey data to time-series aerial photography. Rates of migration and planform evolution were determined through time-series analysis of aerial photography from 1938-2011. Results from this study show that near-bank LWD can have a significant influence on flow patterns through a meander bend and can disrupt helical flow near the outer bank, thereby reducing the effect of the high velocity core on the toe of the bank. Additionally, these effects influence migration rates and the planform evolution of meandering rivers.

  9. Real gas flows with high velocities

    CERN Document Server

    Lunev, Vladimir V

    2009-01-01

    Gasdynamic Model and Equations Outline of the Gasdynamic Model Basic Equations and Postulates Equations of State Kinetic Theory Second Law of Thermodynamics Speed of Sound Integral Equations of Motion Kinematics of Fluid Media Differential Equations of Gasdynamics Rheological Model Initial and Boundary Conditions Similarity and Modeling in Gasdynamics Euler Equations Navier-Stokes Equations Turbulent Flows Viscous and Inviscid Flow Models Inviscid Gasdynamics Stream Function, Potential,

  10. Flow rate-pressure drop relation for deformable shallow microfluidic channels

    Science.gov (United States)

    Christov, Ivan C.; Cognet, Vincent; Stone, Howard A.

    2013-11-01

    Laminar flow in devices fabricated from PDMS causes deformation of the passage geometry, which affects the flow rate-pressure drop relation. Having an accurate flow rate-pressure drop relation for deformable microchannels is of importance given that the flow rate for a given pressure drop can be as much as 500% of the flow rate predicted by Poiseuille's law for a rigid channel. proposed a successful model of the latter phenomenon by heuristically coupling linear elasticity with the lubrication approximation for Stokes flow. However, their model contains a fitting parameter that must be found for each channel shape by performing an experiment. We present a perturbative derivation of the flow rate-pressure drop relation in a shallow deformable microchannel using Kirchoff-Love theory of isotropic quasi-static plate bending and Stokes' equations under a ``double lubrication'' approximation (i.e., the ratio of the channel's height to its width and of the channel's width to its length are both assumed small). Our result contains no free parameters and confirms Gervais et al.'s observation that the flow rate is a quartic polynomial of the pressure drop. ICC was supported by NSF Grant DMS-1104047 and the U.S. DOE through the LANL/LDRD Program; HAS was supported by NSF Grant CBET-1132835.

  11. A generalized Forchheimer radial flow model for constant-rate tests

    Science.gov (United States)

    Liu, Ming-Ming; Chen, Yi-Feng; Zhan, Hongbin; Hu, Ran; Zhou, Chuang-Bing

    2017-09-01

    Models used for data interpretation of constant-rate tests (CRTs) are commonly derived with the assumption of Darcian flow in an idealized integer flow dimension, where the non-Darcian nature of fluid flow and the complexity of flow geometry are disregarded. In this study, a Forchheimer's law-based analytical model is proposed with the assumption of buildup (or drawdown) decomposition for characterizing the non-Darcian flow in a generalized radial formation where the flow dimension n may become non-integer. The proposed model immediately reduces to Barker's (1988) model for Darcian flow in the generalized radial formation and to Mathias et al.'s (2008) model for non-Darcian flow in a two-dimensional confined aquifer. A comparison with numerical simulations shows that the proposed model behaves well at late times for flow dimension n > 1.5. The proposed model is finally applied for data interpretation of the constant-rate pumping tests performed at Ploemeur (Le Borgne et al., 2004), showing that the intrinsic hydraulic conductivity of formations will be underestimated and the specific storage will be overestimated if the non-Darcian effect is ignored. The proposed model is an extension of the generalized radial flow (GRF) model based on Forchheimer's law, which would be of significance for data interpretation of CRTs in aquifers of complex flow geometry in which non-Darcian flow occurs.

  12. HIgh Rate X-ray Fluorescence Detector

    Energy Technology Data Exchange (ETDEWEB)

    Grudberg, Peter Matthew [XIA LLC

    2013-04-30

    The purpose of this project was to develop a compact, modular multi-channel x-ray detector with integrated electronics. This detector, based upon emerging silicon drift detector (SDD) technology, will be capable of high data rate operation superior to the current state of the art offered by high purity germanium (HPGe) detectors, without the need for liquid nitrogen. In addition, by integrating the processing electronics inside the detector housing, the detector performance will be much less affected by the typically noisy electrical environment of a synchrotron hutch, and will also be much more compact than current systems, which can include a detector involving a large LN2 dewar and multiple racks of electronics. The combined detector/processor system is designed to match or exceed the performance and features of currently available detector systems, at a lower cost and with more ease of use due to the small size of the detector. In addition, the detector system is designed to be modular, so a small system might just have one detector module, while a larger system can have many you can start with one detector module, and add more as needs grow and budget allows. The modular nature also serves to simplify repair. In large part, we were successful in achieving our goals. We did develop a very high performance, large area multi-channel SDD detector, packaged with all associated electronics, which is easy to use and requires minimal external support (a simple power supply module and a closed-loop water cooling system). However, we did fall short of some of our stated goals. We had intended to base the detector on modular, large-area detectors from Ketek GmbH in Munich, Germany; however, these were not available in a suitable time frame for this project, so we worked instead with pnDetector GmbH (also located in Munich). They were able to provide a front-end detector module with six 100 m^2 SDD detectors (two monolithic arrays of three elements each) along with

  13. Online monitoring of particle mass flow rate in bottom spray fluid bed coating--development and application.

    Science.gov (United States)

    Wang, Li Kun; Heng, Paul Wan Sia; Liew, Celine Valeria

    2010-08-16

    The primary purpose of this study is to develop a visiometric process analyzer for online monitoring of particle mass flow rate in the bottom spray fluid bed coating process. The secondary purpose is to investigate the influences of partition gap and air accelerator insert size on particle mass flow rate using the developed visiometric process analyzer. Particle movement in the region between the product chamber and partition column was captured using a high speed camera. Mean particle velocity and number of particles in the images were determined by particle image velocimetry and morphological image processing method respectively. Mass flow rate was calculated using particle velocity, number of particles in the images, particle density and size information. Particle velocity and number findings were validated using image tracking and manual particle counting techniques respectively. Validation experiments showed that the proposed method was accurate. Partition gap was found to influence particle mass flow rate by limiting the rate of solids flux into the partition column; the air accelerator insert was found to influence particle mass flow rate by a Venturi effect. Partition gap and air accelerator insert diameter needed to be adjusted accordingly in relation to the other variability sources and diameter of coating cores respectively. The potential, challenges and possible solutions of the proposed visiometric process analyzer were further discussed. Copyright (c) 2010 Elsevier B.V. All rights reserved.

  14. Analysis of electrode system for generation of high-power electrodynamic flow

    Science.gov (United States)

    Rebrov, I. E.; Khomich, V. Yu.; Yamshchikov, V. A.

    2016-08-01

    A high-power electrodynamic flow in atmospheric air is numerically simulated and experimentally studied. An electrode system consisting of a cylindrical plasma emitter and a plane metal grid collector of ions is used to generate a flow with a speed of 2 m/s and a volume rate of 15 L/s.

  15. Cheetah: A high frame rate, high resolution SWIR image camera

    Science.gov (United States)

    Neys, Joel; Bentell, Jonas; O'Grady, Matt; Vermeiren, Jan; Colin, Thierry; Hooylaerts, Peter; Grietens, Bob

    2008-10-01

    A high resolution, high frame rate InGaAs based image sensor and associated camera has been developed. The sensor and the camera are capable of recording and delivering more than 1700 full 640x512pixel frames per second. The FPA utilizes a low lag CTIA current integrator in each pixel, enabling integration times shorter than one microsecond. On-chip logics allows for four different sub windows to be read out simultaneously at even higher rates. The spectral sensitivity of the FPA is situated in the SWIR range [0.9-1.7 μm] and can be further extended into the Visible and NIR range. The Cheetah camera has max 16 GB of on-board memory to store the acquired images and transfer the data over a Gigabit Ethernet connection to the PC. The camera is also equipped with a full CameralinkTM interface to directly stream the data to a frame grabber or dedicated image processing unit. The Cheetah camera is completely under software control.

  16. Passive sampling of perfluorinated chemicals in water: flow rate effects on chemical uptake.

    Science.gov (United States)

    Kaserzon, Sarit L; Vermeirssen, Etiënne L M; Hawker, Darryl W; Kennedy, Karen; Bentley, Christie; Thompson, Jack; Booij, Kees; Mueller, Jochen F

    2013-06-01

    A recently developed modified polar organic chemical integrative sampler (POCIS) provides a means for monitoring perfluorinated chemicals (PFCs) in water. However, changes in external flow rates may alter POCIS sampling behaviour and consequently affect estimated water concentrations of analytes. In this work, uptake kinetics of selected PFCs, over 15 days, were investigated. A flow-through channel system was employed with spiked river water at flow rates between 0.02 and 0.34 m s(-1). PFC sampling rates (Rs) (0.09-0.29 L d(-1) depending on analyte and flow rate) increased from the lowest to highest flow rate employed for some PFCs (MW ≤ 464) but not for others (MW ≥ 500). Rs's for some of these smaller PFCs were increasingly less sensitive to flow rate as this increased within the range investigated. This device shows promise as a sampling tool to support monitoring efforts for PFCs in a range of flow rate conditions. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Target heart rate to determine the normal value of coronary flow reserve during dobutamine stress echocardiography

    Directory of Open Access Journals (Sweden)

    Rousse Maria G

    2011-04-01

    Full Text Available Abstract Background The determination of coronary flow reserve (CFR is an essential concept at the moment of decision-making in ischemic heart disease. There are several direct and indirect tests to evaluate this parameter. In this sense, dobutamine stress echocardiography is one of the pharmacological method most commonly used worldwide. It has been previously demonstrated that CFR can be determined by this technique. Despite our wide experience with dobutamine stress echocardiography, we ignored the necessary heart rate to consider sufficient the test for the analysis of CFR. For this reason, our main goal was to determine the velocity of coronary flow in each stage of dobutamine stress echocardiography and the heart rate value necessary to double the baseline values of coronary flow velocity in the territory of the left anterior descending (LAD coronary artery. Methods A total of 33 consecutive patients were analyzed. The patients included had low risk for coronary artery disease. All the participants underwent dobutamine stress echocardiography and coronary artery flow velocity was evaluated in the distal segment of LAD coronary artery using transthoracic color-Doppler echocardiography. Results The feasibility of determining CFR in the territory of the LAD during dobutamine stress echocardiography was high: 31/33 patients (94%. Mean CFR was 2.67 at de end of dobutamine test. There was an excellent concordance between delta HR (difference between baseline HR and maximum HR and the increase in the CFR (correlation coefficient 0.84. In this sense, we found that when HR increased by 50 beats, CFR was ≥ 2 (CI 93-99.2%. In addition, 96.4% of patients reached a CFR ≥ 2 (IC 91.1 - 99% at 75% of their predicted maximum heart rate. Conclusions We found that the feasibility of dobutamine stress echocardiography to determine CFR in the territory of the LAD coronary artery was high. In this study, it was necessary to achieve a difference of 50 bpm

  18. High-density turbidity currents: Are they sandy debris flows?

    Energy Technology Data Exchange (ETDEWEB)

    Shanmugam, G. [Mobil Exploration and Producing Technical Center, Dallas, TX (United States)

    1996-01-01

    Conventionally, turbidity currents are considered as fluidal flows in which sediment is supported by fluid turbulence, whereas debris flows are plastic flows in which sediment is supported by matrix strength, dispersive pressure, and buoyant lift. The concept of high-density turbidity current refers to high-concentration, commonly non-turbulent, flows of fluids in which sediment is supported mainly by matrix strength, dispersive pressure, and buoyant lift. The conventional wisdom that traction carpets with entrained turbulent clouds on top represent high-density turbidity currents is a misnomer because traction carpets are neither fluidal nor turbulent. Debris flows may also have entrained turbulent clouds on top. The traction carpet/debris flow and the overriding turbulent clouds are two separate entities in terms of flow rheology and sediment-support mechanism. In experimental and theoretical studies, which has linked massive sands and floating clasts to high-density turbidity currents, the term high-density turbidity current has actually been used for laminar flows. In alleviating this conceptual problem, sandy debris flow is suggested as a substitute for high-density turbidity current. Sandy debris flows represent a continuous spectrum of processes between cohesive and cohesionless debris flows. Commonly they are rheologically plastic. They may occur with or without entrained turbulent clouds on top. Their sediment-support mechanisms include matrix strength, dispersive pressure, and buoyant lift. They are characterized by laminar flow conditions, a moderate to high grain concentration, and a low to moderate mud content. Although flows evolve and transform during the course of transport in density-stratified flows, the preserved features in a deposit are useful to decipher only the final stages of deposition. At present, there are no established criteria to decipher transport mechanism from the depositional record.

  19. Microturbulence and Flow Shear in High-performance JET ITB Plasma

    Energy Technology Data Exchange (ETDEWEB)

    R.V. Budny; A. Andre; A. Bicoulet; C. Challis; G.D. Conway; W. Dorland; D.R. Ernst; T.S. Hahm; T.C. Hender; D. McCune; G. Rewoldt; S.E. Sharapov

    2001-12-05

    The transport, flow shear, and linear growth rates of microturbulence are studied for a Joint European Torus (JET) plasma with high central q in which an internal transport barrier (ITB) forms and grows to a large radius. The linear microturbulence growth rates of the fastest growing (most unstable) toroidal modes with high toroidal mode number are calculated using the GS2 and FULL gyrokinetic codes. These linear growth rates, gamma (subscript lin) are large, but the flow-shearing rates, gamma (subscript ExB) (dominated by the toroidal rotation contribution) are also comparably large when and where the ITB exists.

  20. Performance of high-rate gravel-packed oil wells

    Energy Technology Data Exchange (ETDEWEB)

    Unneland, Trond

    2001-05-01

    Improved methods for the prediction, evaluation, and monitoring of performance in high-rate cased-hole gravel-packed oil wells are presented in this thesis. The ability to predict well performance prior to the gravel-pack operations, evaluate the results after the operation, and monitor well performance over time has been improved. This lifetime approach to performance analysis of gravel-packed oil wells contributes to increase oil production and field profitability. First, analytical models available for prediction of performance in gravel-packed oil wells are reviewed, with particular emphasis on high-velocity flow effects. From the analysis of field data from three North Sea oil fields, improved and calibrated cased-hole gravel-pack performance prediction models are presented. The recommended model is based on serial flow through formation sand and gravel in the perforation tunnels. In addition, new correlations for high-velocity flow in high-rate gravel-packed oil wells are introduced. Combined, this improves the performance prediction for gravel-packed oil wells, and specific areas can be targeted for optimized well design. Next, limitations in the current methods and alternative methods for evaluation and comparison of well performance are presented. The most widely used parameter, the skin factor, remains a convenient and important parameter. However, using the skin concept in direct comparisons between wells with different reservoir properties may result in misleading or even invalid conclusions. A discussion of the parameters affecting the skin value, with a clarification of limitations, is included. A methodology for evaluation and comparison of gravel-packed well performance is presented, and this includes the use of results from production logs and the use of effective perforation tunnel permeability as a parameter. This contributes to optimized operational procedures from well to well and from field to field. Finally, the data sources available for

  1. Tangential stretching rate (TSR) analysis of non premixed reactive flows

    KAUST Repository

    Valorani, Mauro

    2016-10-16

    We discuss how the Tangential stretching rate (TSR) analysis, originally developed and tested for spatially homogeneous systems (batch reactors), is extended to spatially non homogeneous systems. To illustrate the effectiveness of the TSR diagnostics, we study the ignition transient in a non premixed, reaction–diffusion model in the mixture fraction space, whose dependent variables are temperature and mixture composition. The reactive mixture considered is syngas/air. A detailed H2/CO mechanism with 12 species and 33 chemical reactions is employed. We will discuss two cases, one involving only kinetics as a model of front propagation purely driven by spontaneous ignition, the other as a model of deflagration wave involving kinetics/diffusion coupling. We explore different aspects of the system dynamics such as the relative role of diffusion and kinetics, the evolution of kinetic eigenvalues, and of the tangential stretching rates computed by accounting for the combined action of diffusion and kinetics as well for kinetics only. We propose criteria based on the TSR concept which allow to identify the most ignitable conditions and to discriminate between spontaneous ignition and deflagration front.

  2. Inspection of Powder Flow During LMD Deposition by High Speed Imaging

    Science.gov (United States)

    Montero, Javier; Rodríguez, Ángel; Amado, José Manuel; Yáñez, Armando J.

    Laser cladding and LMD (Laser Metal Deposition) processes are continuously gaining ground in aerospace and energy industries. One of the known issues with that kind of processes is the difficulty of maintaining a constant and well distributed powder flow mass rate between the nozzle and the substrate. In this work, a method for real time inspection of powder distribution and mass flow rate is presented. Inference of mass flow rate and powder distribution is made using a high speed camera and a laser illumination device. Both on-process and off-process monitoring can be achieved. Different experimental results for the validation of the proposed method are presented.

  3. Formation of the geometrically controlled carbon coils by manipulating the additive gas (SF6) flow rate.

    Science.gov (United States)

    Jeon, Young-Chul; Kim, Sung-Hoon

    2012-07-01

    Carbon coils could be synthesized using C2H2/H2 as source gases and SF6 as an incorporated additive gas under the thermal chemical vapor deposition system. The nickel catalyst layer deposition and then hydrogen plasma pretreatment were performed prior to the carbon coils deposition reaction. The flow rate and the injection time of SF6 varied according to the different reaction processes. Geometries of carbon coils developed from embryos to nanosized coils with increasing SF, flow rate from 5 to 35 sccm under the short SF6 flow injection time (5 minutes) condition. The gradual development of carbon coils geometries from nanosized to microsized types could be observed with increasing SF6 flow rate under the full time (90 minutes) SF6 flow injection condition. The flow rate of SF6 for the coil-type geometry formation should be more than or at least equal to the flow rate of carbon source gas (C2H2). A longer injection time of SF6 flow would increase the size of coils diameters from nanometer to micrometer.

  4. Flow visualization of bubble behavior under two-phase natural circulation flow conditions using high speed digital camera

    Energy Technology Data Exchange (ETDEWEB)

    Lemos, Wanderley F.; Su, Jian, E-mail: wlemos@con.ufrj.br, E-mail: sujian@lasme.coppe.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear; Faccini, Jose L.H., E-mail: faccini@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. de Termo-Hidraulica Experimental

    2013-07-01

    The The present work aims at identifying flow patterns and measuring interfacial parameters in two-phase natural circulation by using visualization technique with high-speed digital camera. The experiments were conducted in the Natural Circulation Circuit (CCN), installed at Nuclear Engineering Institute/CNEN. The thermo-hydraulic circuit comprises heater, heat exchanger, expansion tank, the pressure relief valve and pipes to interconnect the components. A glass tube is installed at the midpoint of the riser connected to the heater outlet. The natural circulation circuit is complemented by acquisition system of values of temperatures, flow and graphic interface. The instrumentation has thermocouples, volumetric flow meter, rotameter and high-speed digital camera. The experimental study is performed through analysis of information from measurements of temperatures at strategic points along the hydraulic circuit, besides natural circulation flow rates. The comparisons between analytical and experimental values are validated by viewing, recording and processing of the images for the flows patterns. Variables involved in the process of identification of flow regimes, dimensionless parameters, the phase velocity of the flow, initial boiling point, the phenomenon of 'flashing' pre-slug flow type were obtained experimentally. (author)

  5. Effects of mass flow rate and droplet velocity on surface heat flux during cryogen spray cooling

    Energy Technology Data Exchange (ETDEWEB)

    Karapetian, Emil [Department of Chemical Engineering and Material Sciences, University of California, Irvine, CA (United States); Aguilar, Guillermo [Department of Biomedical Engineering, University of California, Irvine, CA (United States); Kimel, Sol [Beckman Laser Institute, University of California, Irvine, CA (United States); Lavernia, Enrique J [Department of Chemical Engineering and Material Sciences, University of California, Irvine, CA (United States); Nelson, J Stuart [Department of Biomedical Engineering, University of California, Irvine, CA (United States)

    2003-01-07

    Cryogen spray cooling (CSC) is used to protect the epidermis during dermatologic laser surgery. To date, the relative influence of the fundamental spray parameters on surface cooling remains incompletely understood. This study explores the effects of mass flow rate and average droplet velocity on the surface heat flux during CSC. It is shown that the effect of mass flow rate on the surface heat flux is much more important compared to that of droplet velocity. However, for fully atomized sprays with small flow rates, droplet velocity can make a substantial difference in the surface heat flux. (note)

  6. Measurement of Fluid Flow in Pipe and Porous Media by High-Resolution Magnetic Resonance Imaging

    Institute of Scientific and Technical Information of China (English)

    JIANG Lan-lan; SONG Yong-chen; LIU Yu; DOU Bin-lin; ZHU Ning-jun; ZHAO Jia-fei; BULITI Abudula

    2012-01-01

    The objective of this study is to understand the process of fluid flow in pipe and porous media with different pore structures.High-resolution Magnetic Resonance Imaging (MRI) technique was used to visualize the pore structure and measure fluid flow.The porous media was formed by packed bed of glass beads.Flow measurement was carried out by a modified spin echo sequence.The results show that the velocity distribution in pipe is annular and the linear relation between MRI velocity and actual velocity is found in pipe flow measurement.The flow distribution in porous media is rather heterogeneous,and it is consistent with heterogeneous pore structure.The flow through pores with the high volume flow rate is determined largely by geometrical effects such as pore size and cross-sectional area.

  7. Financial modeling in medicine: cash flow, basic metrics, the time value of money, discount rates, and internal rate of return.

    Science.gov (United States)

    Lexa, Frank James; Berlin, Jonathan W

    2005-03-01

    In this article, the authors cover tools for financial modeling. Commonly used time lines and cash flow diagrams are discussed. Commonly used but limited terms such as payback and breakeven are introduced. The important topics of the time value of money and discount rates are introduced to lay the foundation for their use in modeling and in more advanced metrics such as the internal rate of return. Finally, the authors broach the more sophisticated topic of net present value.

  8. Effects of Temperature, Humidity and Air Flow on Fungal Growth Rate on Loaded Ventilation Filters.

    Science.gov (United States)

    Tang, W; Kuehn, T H; Simcik, Matt F

    2015-01-01

    This study compares the fungal growth ratio on loaded ventilation filters under various temperature, relative humidity (RH), and air flow conditions in a controlled laboratory setting. A new full-size commercial building ventilation filter was loaded with malt extract nutrients and conidia of Cladosporium sphaerospermum in an ASHRAE Standard 52.2 filter test facility. Small sections cut from this filter were incubated under the following conditions: constant room temperature and a high RH of 97%; sinusoidal temperature (with an amplitude of 10°C, an average of 23°C, and a period of 24 hr) and a mean RH of 97%; room temperature and step changes between 97% and 75% RH, 97% and 43% RH, and 97% and 11% RH every 12 hr. The biomass on the filter sections was measured using both an elution-culture method and by ergosterol assay immediately after loading and every 2 days up to 10 days after loading. Fungal growth was detected earlier using ergosterol content than with the elution-culture method. A student's t-test indicated that Cladosporium sphaerospermum grew better at the constant room temperature condition than at the sinusoidal temperature condition. By part-time exposure to dry environments, the fungal growth was reduced (75% and 43% RH) or even inhibited (11% RH). Additional loaded filters were installed in the wind tunnel at room temperature and an RH greater than 95% under one of two air flow test conditions: continuous air flow or air flow only 9 hr/day with a flow rate of 0.7 m(3)/s (filter media velocity 0.15 m/s). Swab tests and a tease mount method were used to detect fungal growth on the filters at day 0, 5, and 10. Fungal growth was detected for both test conditions, which indicates that when temperature and relative humidity are optimum, controlling the air flow alone cannot prevent fungal growth. In real applications where nutrients are less sufficient than in this laboratory study, fungal growth rate may be reduced under the same operating conditions.

  9. Implications of sediment transport by subglacial water flow for interpreting contemporary glacial erosion rates

    Science.gov (United States)

    Beaud, Flavien; Flowers, Gwenn E.; Venditti, Jeremy G.

    2017-04-01

    The role of glaciers in landscape evolution is central to the interactions between climate and tectonic forces at high latitudes and in mountainous regions. Sediment yields from glacierized basins are used to quantify contemporary erosion rates on seasonal to decadal timescales, often under the assumption that subglacial water flow is the main contributor to these yields. Two recent studies have furthermore used such sediment fluxes to calibrate a glacial erosion rule, where erosion rate scales with ice sliding speed raised to a power greater than one. Subglacial sediment transport by water flow has however seldom been studied, thus the controls on sediment yield from glacierized basins remain enigmatic. To bridge this gap, we develop a 1-D model of morphodynamics in semi-circular bedrock-floored subglacial channels. We adapt a sediment conservation law from the fluvial literature, developed for both mixed bedrock / alluvial and alluvial conditions, to subglacial channels. Channel evolution is a function of the traditional melt-opening due to viscous heat dissipation from the water flow, and creep closure of the overlying ice, to which we add the closure or enlargement due to sediment deposition or removal, respectively. Using a simple ice geometry representing a land-terminating glacier, we find that the shear stresses produced by the water flow on the bed decrease significantly near the terminus. As the ice thins, creep closure decreases and large hydraulic potential gradients cannot be sustained. The resulting gradients in sediment transport lead to a bottleneck, and sediment accumulates if the sediment supply is adequate. A similar bottleneck occurs if a channel is well established and water discharge drops. Whether such constriction happens in space of time, in the presence of a sufficiently large sediment supply sediment accumulates temporarily near the terminus, followed shortly thereafter by enhanced sediment transport. Reduction in the cross-sectional area

  10. Measurement of Air Flow Rate in a Naturally Ventilated Double Skin Facade

    DEFF Research Database (Denmark)

    Kalyanova, Olena; Jensen, Rasmus Lund; Heiselberg, Per

    2007-01-01

    Air flow rate in a naturally ventilated space is extremely difficult to measure due to the stochastic nature of wind, and as a consequence non-uniform and dynamic flow conditions. This paper describes three different methods to measure the air flow in a full-scale outdoor test facility...... with a naturally ventilated double skin façade. In the first method, the air flow in the cavity is estimated on the basis of six measured velocity profiles. The second method is represented by constant injection of tracer gas and in the third method a measured relation in the laboratory is used to estimate...... the flow rate on the basis of continues measurement of the pressure difference between the surface pressure at the opening and inside pressure of the double skin façade. Although all three measurement methods are difficult to use under such dynamic air flow conditions, two of them show reasonable agreement...

  11. CASH FLOW IMPLICATIONS OF FIXED VERSUS VARIABLE INTEREST RATE DEBT STRUCTURES

    OpenAIRE

    Moe, Lonn; Thompson, Jerry L.

    1984-01-01

    The objective of this study was to discover the magnitude of the effect variable rate loans have on net operating cash flow over the period from 1968 to 1981. This was done by comparing a variable rate loan model with a fixed rate loan model under varying debt loads for four farm types.

  12. CASH FLOW IMPLICATIONS OF FIXED VERSUS VARIABLE INTEREST RATE DEBT STRUCTURES

    OpenAIRE

    Moe, Lonn; Thompson, Jerry L.

    1984-01-01

    The objective of this study was to discover the magnitude of the effect variable rate loans have on net operating cash flow over the period from 1968 to 1981. This was done by comparing a variable rate loan model with a fixed rate loan model under varying debt loads for four farm types.

  13. Power flow controller with a fractionally rated back-to-back converter

    Science.gov (United States)

    Divan, Deepakraj M.; Kandula, Rajendra Prasad; Prasai, Anish

    2016-03-08

    A power flow controller with a fractionally rated back-to-back (BTB) converter is provided. The power flow controller provide dynamic control of both active and reactive power of a power system. The power flow controller inserts a voltage with controllable magnitude and phase between two AC sources at the same frequency; thereby effecting control of active and reactive power flows between the two AC sources. A transformer may be augmented with a fractionally rated bi-directional Back to Back (BTB) converter. The fractionally rated BTB converter comprises a transformer side converter (TSC), a direct-current (DC) link, and a line side converter (LSC). By controlling the switches of the BTB converter, the effective phase angle between the two AC source voltages may be regulated, and the amplitude of the voltage inserted by the power flow controller may be adjusted with respect to the AC source voltages.

  14. Effects of neuropeptide Y on regulation of blood flow rate in canine myocardium

    DEFF Research Database (Denmark)

    Svendsen, Jesper Hastrup; Sheikh, S P; Jørgensen, J

    1990-01-01

    The effect of neuropeptide Y (NPY) on tension development was examined in isolated canine coronary arteries, and the effects on local myocardial blood flow rate were studied in open-chest anesthetized dogs by the local 133Xe washout technique. By immunohistochemistry, numerous NPY......+. In contrast, intracoronary NPY (0.01-10 micrograms) induced a considerable degree of vasoconstriction; the reduction of blood flow rate was dose related, with a maximum reduction to 52% of control values. The effect of intracoronary NPY (1 microgram) on maximally relaxed arterioles elicited by 30 s...... of ischemia was studied in separate experiments during reactive hyperemia. NPY induced a decrease in maximum blood flow during reactive hyperemia (166.6 vs. 214.6% of preocclusive blood flow rate, mean values; P = 0.05), an increase in the cumulative excess blood flow (61.0 vs. 35.3 ml/100 g; P = 0...

  15. Effects of Asymmetrical Micro Electrode Surface Topography to AC Electroosmosis flow Rate

    CERN Document Server

    Hong-Yuan, Jiang; Zhen-Xiu, Hou; Yu-Kun, Ren; Yong-Jun, Sun

    2010-01-01

    AC Electroosmosis (ACEO) has many advantages such as low power consumption, non-moving parts, and easy to integrate etc., so it is widely used for low concentration microfluid manipulation in low frequency range. Classical ACEO theory assumes that electric double layer (EDL) is the main cause of electric field induced flow, and gives electric-flow field coupling equations for ACEO flow rate. But the calculation data usually are tens times faster than the experimental velocities. In this paper, electrode surface topography is included to solve ACEO flow rate. With electrode surface roughness as the characteristic parameter, equivalent EDL model is set up to modify the classical EDL model. The relationship between flow rate and electrode surface roughness is studied. Experiment results agree with the simulation very well, proving the feasibility of equivalent EDL model.

  16. Optimization of carbon dioxide supply in raceway reactors: Influence of carbon dioxide molar fraction and gas flow rate.

    Science.gov (United States)

    Duarte-Santos, T; Mendoza-Martín, J L; Acién Fernández, F G; Molina, E; Vieira-Costa, J A; Heaven, S

    2016-07-01

    Influence of CO2 composition and gas flow rate to control pH in a pilot-scale raceway producing Scenedesmus sp. was studied. Light and temperature determined the biomass productivity whereas neither the CO2 molar fraction nor the gas flow rate used influenced it; because pH was always controlled and carbon limitation did not take place. The CO2 molar fraction and the gas flow rate influenced carbon loss in the system. At low CO2 molar fraction (2-6%) or gas flow rate (75-100l·min(-1)) the carbon efficiency in the sump was higher than 95%, 85% of the injected carbon being transformed into biomass. Conversely, at high CO2 molar fraction (14%) or gas flow rate (150l·min(-1)) the carbon efficiency in the sump was lower than 67%, 32% of the carbon being fixed as biomass. Analysis here reported allows the pH control to be optimized and production costs to be reduced by optimizing CO2 efficiency.

  17. Influences of gas flow rates on melting of particles of HVOF sprayed CoCrW coating and coating properties

    Institute of Scientific and Technical Information of China (English)

    YANG Zhongyuan

    2004-01-01

    This paper discussed influences of flow rates of O2, C3H8, and compressed air on the melting degree of particles during HVOF (high velocity oxy-fuel) sprayed CoCrW coating. The O2 flow rate has the maximal effect on the melting of particles, the C3H8 flow rate has the second, and the compressed air flow rate has the minimal effect. The bond strength of the HVOF sprayed CoCrW coating is over 54 MPa. The porosity ratio of the HVOF sprayed CoCrW coating after optimization of gas flow rates is less than 2%. The average microhardness of the coating is up to HV0.1 545. The oxidation amount per unit area of the HVOF sprayed CoCrW coating increases with the holding time increasing at 800°C. In the same way,the oxidation amount of the coating increases as the temperature increases. Particularly, the oxidation of the coating drastically increases over 850°C.

  18. Effect of Flow Velocity on Corrosion Rate and Corrosion Protection Current of Marine Material

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seong Jong [Kunsan National University, Kunsan (Korea, Republic of); Han, Min Su; Jang, Seok Ki; Kim, Seong Jong [Mokpo National Maritime University, Mokpo (Korea, Republic of)

    2015-10-15

    In spite of highly advanced paint coating techniques, corrosion damage of marine metal and alloys increase more and more due to inherent micro-cracks and porosities in coatings formed during the coating process. Furthermore, flowing seawater conditions promote the breakdown of the protective oxide of the materials introducing more oxygen into marine environments, leading to the acceleration of corrosion. Various corrosion protection methods are available to prevent steel from marine corrosion. Cathodic protection is one of the useful corrosion protection methods by which the potential of the corroded metal is intentionally lowered to an immune state having the advantage of providing additional protection barriers to steel exposed to aqueous corrosion or soil corrosion, in addition to the coating. In the present investigation, the effect of flow velocity was examined for the determination of the optimum corrosion protection current density in cathodic protection as well as the corrosion rate of the steel. It is demonstrated from the result that the material corrosion under dynamic flowing conditions seems more prone to corrosion than under static conditions.

  19. Evaluation of the impact of viscosity, injection volume, and injection flow rate on subcutaneous injection tolerance

    Directory of Open Access Journals (Sweden)

    Berteau C

    2015-11-01

    Full Text Available Cecile Berteau,1 Orchidée Filipe-Santos,1 Tao Wang,2 Humberto E Rojas,2 Corinne Granger,1 Florence Schwarzenbach1 1Becton-Dickinson Medical Pharmaceutical Systems, Le Pont de Claix, France; 2Eli Lilly and Company, Indianapolis, IN, USA Aim: The primary objective of this study was to evaluate the impact of fluid injection viscosity in combination with different injection volumes and flow rates on subcutaneous (SC injection pain tolerance. Methods: The study was a single-center, comparative, randomized, crossover, Phase I study in 24 healthy adults. Each participant received six injections in the abdomen area of either a 2 or 3 mL placebo solution, with three different fluid viscosities (1, 8–10, and 15–20 cP combined with two different injection flow rates (0.02 and 0.3 mL/s. All injections were performed with 50 mL syringes and 27G, 6 mm needles. Perceived injection pain was assessed using a 100 mm visual analog scale (VAS (0 mm/no pain, 100 mm/extreme pain. The location and depth of the injected fluid was assessed through 2D ultrasound echography images. Results: Viscosity levels had significant impact on perceived injection pain (P=0.0003. Specifically, less pain was associated with high viscosity (VAS =12.6 mm than medium (VAS =16.6 mm or low (VAS =22.1 mm viscosities, with a significant difference between high and low viscosities (P=0.0002. Target injection volume of 2 or 3 mL was demonstrated to have no significant impact on perceived injection pain (P=0.89. Slow (0.02 mL/s or fast (0.30 mL/s injection rates also showed no significant impact on perceived pain during SC injection (P=0.79. In 92% of injections, the injected fluid was located exclusively in SC tissue whereas the remaining injected fluids were found located in SC and/or intradermal layers. Conclusion: The results of this study suggest that solutions of up to 3 mL and up to 15–20 cP injected into the abdomen within 10 seconds are well tolerated without pain. High

  20. Evaluation of the impact of viscosity, injection volume, and injection flow rate on subcutaneous injection tolerance.

    Science.gov (United States)

    Berteau, Cecile; Filipe-Santos, Orchidée; Wang, Tao; Rojas, Humberto E; Granger, Corinne; Schwarzenbach, Florence

    2015-01-01

    The primary objective of this study was to evaluate the impact of fluid injection viscosity in combination with different injection volumes and flow rates on subcutaneous (SC) injection pain tolerance. The study was a single-center, comparative, randomized, crossover, Phase I study in 24 healthy adults. Each participant received six injections in the abdomen area of either a 2 or 3 mL placebo solution, with three different fluid viscosities (1, 8-10, and 15-20 cP) combined with two different injection flow rates (0.02 and 0.3 mL/s). All injections were performed with 50 mL syringes and 27G, 6 mm needles. Perceived injection pain was assessed using a 100 mm visual analog scale (VAS) (0 mm/no pain, 100 mm/extreme pain). The location and depth of the injected fluid was assessed through 2D ultrasound echography images. Viscosity levels had significant impact on perceived injection pain (P=0.0003). Specifically, less pain was associated with high viscosity (VAS =12.6 mm) than medium (VAS =16.6 mm) or low (VAS =22.1 mm) viscosities, with a significant difference between high and low viscosities (P=0.0002). Target injection volume of 2 or 3 mL was demonstrated to have no significant impact on perceived injection pain (P=0.89). Slow (0.02 mL/s) or fast (0.30 mL/s) injection rates also showed no significant impact on perceived pain during SC injection (P=0.79). In 92% of injections, the injected fluid was located exclusively in SC tissue whereas the remaining injected fluids were found located in SC and/or intradermal layers. The results of this study suggest that solutions of up to 3 mL and up to 15-20 cP injected into the abdomen within 10 seconds are well tolerated without pain. High viscosity injections were shown to be the most tolerated, whereas injection volume and flow rates did not impact perceived pain.

  1. Particle Flow Cell Formation at Minimum Fluidization Flow Rates in a Rectangular Gas-Fluidized Bed.

    Science.gov (United States)

    1981-03-01

    Kunii and Levenspiel Model ----------------- 66 C. FLUIDIZED BED VARIABLES THAT AFFECT HEAT TRANSFER ---------------------------------- 69 5 1...and Levenspiel Model -------------------------- 68 25. Heat transfer coefficient vs. mass velocity --------- 72 26. Contact geometry of surface-particle...becomes a very important factor. According to Kunii and Levenspiel [34], distributors should have a sufficient pressure drop to achieve equal flow

  2. The Myth of a High Savings Rate

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    In an attempt to entice consumers to save less and spend more, China has focused on perfecting its social security system, reforming taxation and dividend-sharing proportion between the government and state-owned enterprises. Liu Yuhui, Director of the China Economy Appraisal and Rating Center at the Institute of Finance and Banking, the Chinese Academy of Social Sciences, offered his insights in an Economic Observer article. Edited excerpts follow

  3. Numerical Simulation for Effect of Inlet Cooling Rate on Fluid Flow and Temperature Distribution in Tundish

    Institute of Scientific and Technical Information of China (English)

    QU Tian-peng; LIU Cheng-jun; JIANG Mao-fa

    2012-01-01

    The fluid flow in tundish is a non-isothermal process and the temperature variation of stream from teeming ladle dominates the fluid flow and thermal distribution in tundish. A numerical model was established to investigate the effect of inlet cooling rate on fluid flow and temperature distribution in tundish based on a FTSC (Flexible Thin Slab Casting) tundish. The inlet cooling rate varies from 0. 5 to 0. 25 ~C/rain. Under the present calculation conditions, the following conclusions were made. When the stream temperature from teeming ladle drops seriously (for inlet cooling rate of 0.5℃/min), there is a "backward flow" at the coming end of casting. The horizontal flow along the free surface turns to flow along the bottom of tundish. The bottom flow shortens the fluid flow route in tundish and deteriorates the removal effect of nonmetallic inclusions from molten steel. Nevertheless, when the inlet cooling rate decreases to 0.25℃/min, the horizontal flow is sustained during the whole casting period. The present research provides theoretical directions for temperature control in teeming ladle and continuous casting tundish during production of advanced steels.

  4. Flow Control Strategy for the High Speed Network Based on Control Theory

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Design of an effective congestion control scheme is a hot topic in the development of computer network. The flow control scheme can adjust the packet sending rate in source host, thus effectively avoiding the network congestion. This paper proposes a new flow control scheme based on discrete control theory. The simulation results show that this method can adjust the sending rate and queue level in buffer rapidly and effectively. The method is easy to implement and applicable to high speed networks.

  5. A Distributed Flow Rate Control Algorithm for Networked Agent System with Multiple Coding Rates to Optimize Multimedia Data Transmission

    Directory of Open Access Journals (Sweden)

    Shuai Zeng

    2013-01-01

    Full Text Available With the development of wireless technologies, mobile communication applies more and more extensively in the various walks of life. The social network of both fixed and mobile users can be seen as networked agent system. At present, kinds of devices and access network technology are widely used. Different users in this networked agent system may need different coding rates multimedia data due to their heterogeneous demand. This paper proposes a distributed flow rate control algorithm to optimize multimedia data transmission of the networked agent system with the coexisting various coding rates. In this proposed algorithm, transmission path and upload bandwidth of different coding rate data between source node, fixed and mobile nodes are appropriately arranged and controlled. On the one hand, this algorithm can provide user nodes with differentiated coding rate data and corresponding flow rate. On the other hand, it makes the different coding rate data and user nodes networked, which realizes the sharing of upload bandwidth of user nodes which require different coding rate data. The study conducts mathematical modeling on the proposed algorithm and compares the system that adopts the proposed algorithm with the existing system based on the simulation experiment and mathematical analysis. The results show that the system that adopts the proposed algorithm achieves higher upload bandwidth utilization of user nodes and lower upload bandwidth consumption of source node.

  6. The Combustion of HMX. [burning rate at high pressures

    Science.gov (United States)

    Boggs, T. L.; Price, C. F.; Atwood, A. I.; Zurn, D. E.; Eisel, J. L.

    1980-01-01

    The burn rate of HMX was measured at high pressures (p more than 1000 psi). The self deflagration rate of HMX was determined from 1 atmosphere to 50,000 psi. The burning rate shows no significant slope breaks.

  7. ALICE TPC upgrade for High-Rate operations

    CERN Document Server

    ,

    2015-01-01

    A new type of Time Projection Chamber (TPC) has been proposed for the upgrade of the ALICE (A Large Ion Collider Experiment at CERN) so as to cater to the high luminosity environment expected at the Large Hadron Collider (LHC) facility in future. This device will rely on the intrinsic ion back flow (IBF) suppression of Micro-Pattern Gas Detectors (MPGD) based technology in particular the Gas Electron Multiplier (GEM). GEM is to minimise the space charge effect in the main drift volume and thus will not require the standard gating grid and the resulting intrinsic dead time. It will thus be possible to read all minimum bias Pb--Pb events that the Large Hadron Collider (LHC) will deliver at the anticipated peak interaction rate of 50 kHz for the high luminosity heavy-ion era in Run 3. New read-out electronics will send the continuous data stream to a new online farm at rates up to 1~TByte/s. The new read-out chambers will consist of stacks of 4 GEM foils combining different hole pitches. In addition to a low ion...

  8. Effects of the flow rate of hydrogen on the growth of graphene

    Institute of Scientific and Technical Information of China (English)

    Yong-gui Shi; Yue Hao; Dong Wang; Jin-cheng Zhang; Peng Zhang; Xue-fang Shi; Dang Han; Zheng Chai; Jing-dong Yan

    2015-01-01

    Graphene samples with different morphologies were fabricated on the inside of copper enclosures by low pressure chemical vapor deposition and tuning the flow rate of hydrogen. It is found that the flow rate of hydrogen greatly influences the growth of graphene. Ther-modynamic analysis indicates that a higher flow rate of hydrogen is favorable to the formation of good quality graphene with regular mor-phology. However, the mass-transfer process of methane dominates the growth driving force. At very low pressure, mass-transfer proceeds by Knudsen diffusion, and the mass-transfer flux of methane decreases as the flow rate of hydrogen increases, leading to a decrease in the growth driving force. At a higher pressure, mass-transfer proceeds by Fick’s diffusion, and the mass-transfer flux of methane is dominated by the gas velocity, whose variation determines the growth driving force variation of graphene.

  9. Passive sampling of perfluorinated chemicals in water: Flow rate effects on chemical uptake

    NARCIS (Netherlands)

    Kaserzon, S.L.; Vermeirssen, E.L.M.; Hawker, D.W.; Kennedy, K.; Bentley, C.; Thompson, J.; Booij, K.; Mueller, J.F.

    2013-01-01

    A recently developed modified polar organic chemical integrative sampler (POCIS) provides a means for monitoring perfluorinated chemicals (PFCs) in water. However, changes in external flow rates may alter POCIS sampling behaviour and consequently affect estimated water concentrations of analytes. In

  10. Relationship between Supplied Oil Flow Rates and Oil Film Thicknesses under Starved Elastohydrodynamic Lubrication

    Directory of Open Access Journals (Sweden)

    Taisuke Maruyama

    2015-04-01

    Full Text Available Many studies have already considered starved lubrication. However, there have been no reports on the oil film thicknesses under steady starved EHL (elastohydrodynamic lubrication, where the ultra-low volume of oil supplied per unit time is uniform. The present study examined the relationship between the supplied oil flow rate and oil film thickness under steady starved lubrication. A ball-on-disk testing machine was used in experiments to measure the oil film thickness by means of optical interferometry. A microsyringe pump was used to accurately control the supplied oil flow rate. The supplied oil flow rate was kept constant, and the minimum oil film thickness was measured for 1 h after the start of the tests to determine the relationship between the supplied oil flow rate and oil film thickness.

  11. Influence of carrier gas flow rate on carbon nanotubes growth by TCVD with Cu catalyst

    Directory of Open Access Journals (Sweden)

    S.A. Khorrami

    2016-07-01

    Full Text Available Carbon nanotubes (CNTs were grown on copper catalyst by thermal chemical vapor deposition (TCVD using H2 and N2 as carrier gases. CNTs with different morphologies were observed using different carrier gas flow rates. The influence of carrier gas flow rates on the structure of carbon nanotubes was compared. Catalyst nanolayer was sputtered on mirror polished silicon wafers. The catalyst film thickness was determined by using the Rutherford Back Scattering (RBS technique. Ethanol as carbon source has been used. The surface morphology and nanostructure were studied by Scanning Electron Microscopy (SEM, Raman Spectroscopy, Tunneling Electron Microscopy (TEM and Atomic Force Microscopy (AFM. Results indicated that the amounts of deposited carbon decrease with increasing flow rates. These results showed that CNTs’ length decreased with increasing flow rates. Results suggest that Cu nanolayer is suitable as catalyst due to the fact that CNTs are monotonous.

  12. An in vivo assessment of the influence of needle gauges on endodontic irrigation flow rate

    Directory of Open Access Journals (Sweden)

    Velayutham Gopikrishna

    2016-01-01

    Statistical Analysis Used: The following tests were used for the statistical analysis: Independent sample "T" test, one-way ANOVA test, and post hoc multiple comparison was carried out using Tukey′s honest significant difference (HSD test using Statistical Package for the Social Sciences (SPSS version 16 for Windows. Results: The average flow rate of 26 gauge was 0.27 mLs−1 , of 27 gauge was 0.19 mLs−1 , and of 30 gauge was 0.09 mls−1 . There was statistical significance among the gauges (P < 0.001. 26 gauge had highest flow rate when compared with other groups followed by 27 gauge and 30 gauge respectively. The operator variability for flow rate of three endodontic irrigation needle gauges (26 gauge, 27 gauge, and 30 gauge was found to be not significant. Conclusions: Needle gauge has significant influence on endodontic irrigation flow rate.

  13. LIQUID ARGON CALORIMETER PERFORMANCE AT HIGH RATES

    CERN Document Server

    Kukhtin, V; The ATLAS collaboration

    2011-01-01

    The performance of the ATLAS liquid argon endcap and forward calorimeters has been projected at the planned high luminosity LHC option HL-LHC by exposing small calorimeter modules of the electromagnetic, hadronic, and forward calorimeters to high intensity proton beams at IHEP/Protvino accelerator. The results of HV current and of pulse shape analysis, and also the dependence of signal amplitude on beam intensity are presented.

  14. Two Models of DMFC under Effects of Cathode Humidification Temperature and Anode Flow Rate

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    This paper introduced a novel self-adjustment of parameters of fuzzy neural networks. Then,the effects of cathode humidification temperature and anode flow rate on the performance of direct methanol fuel cell (DMFC)were described respectively. Two dynamic performance models of DMFC under the influences of cathode humidification temperature and anode flow rate were established separately based on fuzzy neural networks. The simulation results show the accuracy of the models established is satisfactory.

  15. Flow Rates in Liquid Chromatography, Gas Chromatography and Supercritical Fluid Chromatography: A Tool for Optimization

    OpenAIRE

    Joris Meurs

    2016-01-01

    This paper aimed to develop a standalone application for optimizing flow rates in liquid chromatography (LC), gas chromatography (GC) and supercritical fluid chromatography (SFC). To do so, Van Deemter’s equation, Knox’ equation and Golay’s equation were implemented in a MATLAB script and subsequently a graphical user interface (GUI) was created. The application will show the optimal flow rate or linear velocity and the corresponding plate height for the set input parameters. Furthermore, a p...

  16. Effect of Flow Rate of Side-Type Orifice Intake on Withdrawn Water Temperature

    OpenAIRE

    Xueping Gao; Guangning Li; Yunpeng Han

    2014-01-01

    Side-type orifice intake is a type of selective withdrawal facility used in managing reservoirs to mitigate the negative effects of low-temperature water. Based on the temperature data of a thermal stratified reservoir in China, an experiment was conducted in flume to study the influence of intake flow rate on withdrawn water temperature with different temperature distributions. Results indicated that withdrawn water temperature changed with different flow rates. The temperature change was de...

  17. High Reproduction Rate versus Sexual Fidelity

    OpenAIRE

    Sousa, A. O.; de Oliveira, S. Moss

    2000-01-01

    We introduce fidelity into the bit-string Penna model for biological ageing and study the advantage of this fidelity when it produces a higher survival probability of the offspring due to paternal care. We attribute a lower reproduction rate to the faithful males but a higher death probability to the offspring of non-faithful males that abandon the pups to mate other females. The fidelity is considered as a genetic trait which is transmitted to the male offspring (with or without error). We s...

  18. Couette and Poiseuille flows in a low viscosity asthenosphere: Effects of internal heating rate, Rayleigh number, and plate representation

    Science.gov (United States)

    Shiels, C.; Butler, S. L.

    2015-09-01

    Mantle convection models with a low viscosity asthenosphere and high viscosity surface plates have been shown to produce very large aspect ratio convection cells like those inferred to exist in Earth's mantle and to exhibit two asthenospheric flow regimes. When the surface plate is highly mobile, the plate velocity exceeds the flow velocities in the asthenosphere and the plate drives a Couette-type flow in the asthenospheric channel. For sluggish plates, the flow velocities in the asthenosphere exceed the plate velocity and the asthenospheric flow is more Poiseuille-like. It has been shown that under certain circumstances, flows become increasingly Couette-like as the aspect ratio of the plate is increased in numerical simulations. These models also show an increase in the average surface heat flux with aspect ratio which is counterintuitive, as one would expect that large aspect ratio models would result in older and colder oceanic lithosphere. Previous investigations have used single internal heating rates and Rayleigh numbers and a plate formulation that did not preclude significant deformation within the plate. In this paper, we investigate the conditions necessary for Couette and Poiseuille asthenospheric flows and for surface heat flux to increase with plate aspect ratio by varying the internal heating rate, the Rayleigh number and the representation of surface plates in 2D mantle convection models Plates are represented as a high viscosity layer with (1) a free-slip top surface boundary condition and (2) a force-balance boundary condition that imposes a constant surface velocity within the plate. We find that for models with a free-slip surface boundary condition, the internal heating rate and Rayleigh number do not strongly affect the dominance of Couette or Poiseuille flows in the asthenosphere but the increase in surface heat flux with model aspect ratio in the Poiseuille asthenospheric flow regime increases with internal heating rate. For models using

  19. R&D on Resistive Heat Exchangers for HTS High Rated Current Leads%R&D on Resistive Heat Exchangers for HTS High Rated Current Leads

    Institute of Scientific and Technical Information of China (English)

    毕延芳

    2011-01-01

    The HTS current leads of superconducting magnets for large scale fusion devices and high energy particle colliders can reduce the power consumption for cooling by 2/3 compared with conventional leads. The resistive sections of high-rated current leads are usually made of a heat exchanger cooled by gas flow. The supply of the cooling mass flow incurs more than 90% of the cooling cost for the HTS leads. The mass flow rate requirement depends not only on the length and material of the resistive heat exchanger, but also on the heat transfer coefficient and HEX surface, the joint resistance at the cold end of a sheet-stack HEX with a larger specific presented in the paper. The test results of efficiency can be achieved. and its cooling approach. The design and operation surface and a much smaller hydraulic diameter are an HTS lead optimized for 8 kA show that a 98.4%

  20. Field Measurements of Influence of Sand Transport Rate on Structure of Wind-sand Flow over Coastal Transverse Ridge

    Institute of Scientific and Technical Information of China (English)

    DONG Yuxiang; S L NAMIKAS; P A HESP; MA Jun

    2008-01-01

    The structure of wind-sand flow under different total sand transport rates was measured with field vertical anemometer and sand trap on the crest of typical coastal transverse ridge in Changli Gold Coast of Hebei Province,which is one of the most typical coastal aeolian distribution regions in China and famous for the tall and typical coastal transverse ridges.The measurement results show that,on the conditions of approximate wind velocities and same surface materials and environments,some changes happen to the structure of wind-sand flow with the increase of total sand transport rate on the crest of coastal transverse ridge.First,the sand transport rates of layers at different heights in the wind-sand flow increase,with the maximum increase at the height layer of 4-8cm.Second,the ratios of sand transport rates of layers at different heights to total sand transport rate decrease at the low height layer (0-4cm),but increase at the high height layer (4-60cm).Third,the distribution of the sand transport rate in the wind-sand flow can be expressed by an exponential function at the height layer of 0-40cm,but it changes fi'om power function model to exponential function model in the whole height layer (0-60cm) and changes into polynomial function model at the height layer of 40-60cm with the increase of total sand transport rate.Those changes have a close relationship with the limit of sand grain size of wind flow transporting and composition of sand grain size in the wind-sand flow.

  1. Smoking Rates Still High in Some Racial Groups, CDC Reports

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_160256.html Smoking Rates Still High in Some Racial Groups, CDC ... lot of progress in getting Americans to stop smoking, some groups still have high smoking rates, a ...

  2. Risk Factors for Reduced Salivary Flow Rate in a Japanese Population: The Hisayama Study

    Directory of Open Access Journals (Sweden)

    Kenji Takeuchi

    2015-01-01

    Full Text Available The purpose of this study was to determine distinct risk factors causing reduced salivary flow rate in a community-dwelling population using a prospective cohort study design. This was a 5-year follow-up survey of 1,377 community-dwelling Japanese individuals aged ≥40 years. The salivary flow rate was evaluated at baseline and follow-up by collecting stimulated saliva. Data on demographic characteristics, use of medication, and general and oral health status were obtained at baseline. The relationship between reduced salivary flow rate during the follow-up period and its predictors was evaluated after adjustment for confounding factors. In a multivariate logistic regression model, higher age and plaque score and lower serum albumin levels were significantly associated with greater odds of an obvious reduction in salivary flow rate (age per decade, odds ratio [OR] = 1.25, 95% confidence interval [CI] = 1.03–1.51; serum albumin levels <4 g/dL, OR = 1.60, 95% CI = 1.04–2.46; plaque score ≥1, OR = 1.53, 95% CI = 1.04–2.24. In a multivariate linear regression model, age and plaque score remained independently associated with the increased rate of reduced salivary flow. These results suggest that aging and plaque score are important predictors of reduced salivary flow rate in Japanese adults.

  3. Flow rate of polygonal grains through a bottleneck: Interplay between shape and size

    Directory of Open Access Journals (Sweden)

    Ezequiel Goldberg

    2015-11-01

    Full Text Available We report two-dimensional simulations of circular and polygonal grains passing through an aperture at the bottom of a silo. The mass flow rate for regular polygons is lower than for disks\\red{,} as observed by other authors. We show that both the exit velocity of the grains and the packing fraction are lower for polygons, which leads to the reduced flow rate. We point out the importance of the criteria used to define when two objects of different shape are considered to be of the same size. Depending on this criteria, the mass flow rate may vary significantly for some polygons. Moreover, the particle flow rate is non-trivially related to a combination of mass flow rate, particle shape and particle size. For some polygons, the particle flow rate may be lower or higher than that of the corresponding disks depending on the size comparison criteria. Received: 18 May 2015, Accepted: 30 October 2015; Edited by: F. Melo; Reviewed by: J.-N. Roux, Universite Parsi Est, Laboratoire Navier, Champs-sur-Marne, France; DOI: http://dx.doi.org/10.4279/PIP.070016 Cite as: E Goldberg, C M Carlevaro, L A Pugnaloni, Papers in Physics 7, 070016 (2015

  4. Flow rate dictates permeability enhancement during fluid pressure oscillations in laboratory experiments

    Science.gov (United States)

    Candela, Thibault; Brodsky, Emily E.; Marone, Chris; Elsworth, Derek

    2015-04-01

    Seismic waves have been observed to increase the permeability in fractured aquifers. A detailed, predictive understanding of the process has been hampered by a lack of constraint on the primary physical controls. What aspect of the oscillatory forcing is most important in determining the magnitude of the permeability enhancement? Here we present laboratory results showing that flow rate is the primary control on permeability increases in the laboratory. We fractured Berea sandstone samples under triaxial stresses of tens of megapascals and applied dynamic fluid stresses via pore pressure oscillations. In each experiment, we varied either the amplitude or the frequency of the pressure changes. Amplitude and frequency each separately correlated with the resultant permeability increase. More importantly, the permeability changes correlate with the flow rate in each configuration, regardless of whether flow rate variations were driven by varying amplitude or frequency. We also track the permeability evolution during a single set of oscillations by measuring the phase lags (time delays) of successive oscillations. Interpreting the responses with a poroelastic model shows that 80% of the permeability enhancement is reached during the first oscillation and the final permeability enhancement scales exponentially with the imposed change in flow rate integrated over the rock volume. The establishment of flow rate as the primary control on permeability enhancement from seismic waves opens the door to quantitative studies of earthquake-hydrogeological coupling. The result also suggests that reservoir permeability could be engineered by imposing dynamic stresses and changes in flow rate.

  5. Dental erosive wear and salivary flow rate in physically active young adults

    Directory of Open Access Journals (Sweden)

    Mulic Aida

    2012-03-01

    Full Text Available Abstract Background Little attention has been directed towards identifying the relationship between physical exercise, dental erosive wear and salivary secretion. The study aimed i to describe the prevalence and severity of dental erosive wear among a group of physically active young adults, ii to describe the patterns of dietary consumption and lifestyle among these individuals and iii to study possible effect of exercise on salivary flow rate. Methods Young members (age range 18-32 years of a fitness-centre were invited to participate in the study. Inclusion criteria were healthy young adults training hard at least twice a week. A non-exercising comparison group was selected from an ongoing study among 18-year-olds. Two hundred and twenty participants accepted an intraoral examination and completed a questionnaire. Seventy of the exercising participants provided saliva samples. The examination was performed at the fitness-centre or at a dental clinic (comparison group, using tested erosive wear system (VEDE. Saliva sampling (unstimulated and stimulated was performed before and after exercise. Occlusal surfaces of the first molars in both jaws and the labial and palatal surfaces of the upper incisors and canines were selected as index teeth. Results Dental erosive wear was registered in 64% of the exercising participants, more often in the older age group, and in 20% of the comparison group. Enamel lesions were most observed in the upper central incisors (33%; dentine lesions in lower first molar (27%. One fourth of the participants had erosive wear into dentine, significantly more in males than in females (p = 0.047. More participants with erosive wear had decreased salivary flow during exercise compared with the non-erosion group (p Conclusion The study showed that a high proportion of physically active young adults have erosive lesions and indicate that hard exercise and decreased stimulated salivary flow rate may be associated with such

  6. High frame rate imaging based photometry

    DEFF Research Database (Denmark)

    Harpsøe, Kennet Bomann West; Jørgensen, U. G.; Andersen, M. I.;

    2012-01-01

    in conventional CCDs, and new methods for handling these must be developed. We aim to investigate how the normal photometric reduction steps from conventional CCDs should be adjusted to be applicable to EMCCD data. One complication is that a bias frame cannot be obtained conventionally, as the output from...... an EMCCD is not normally distributed. Also, the readout process generates spurious charges in any CCD, but in EMCCD data, these charges are visible as opposed to the conventional CCD. Furthermore we aim to eliminate the photon waste associated with lucky imaging by combining this method with shift......-and-add. A simple probabilistic model for the dark output of an EMCCD is developed. Fitting this model with the expectation-maximization algorithm allows us to estimate the bias, readout noise, amplification, and spurious charge rate per pixel and thus correct for these phenomena. To investigate the stability...

  7. A constant air flow rate control of blower for residential applications

    Energy Technology Data Exchange (ETDEWEB)

    Yang, S.M. [Tamkang Univ., Taipei (Taiwan, Province of China). Dept. of Mechanical Engineering

    1998-03-01

    This paper presents a technique to control a blower for residential applications at constant air flow rate using an induction motor drive. The control scheme combines a variable volt/hertz ratio inverter drive and an average motor current regulation loop to achieve control of the motor torque-speed characteristics, consequently controlling the air flow rate of the blower which the motor is driving. The controller is simple to implement and practical for commercialization. It is also reliable, since no external pressure or air flow sensor is required. Both a theoretical derivation and an experimental verification for the control scheme are presented in this paper.

  8. He flow rate measurements on the engineering model for the Astro-H Soft X-ray Spectrometer dewar

    Science.gov (United States)

    Mitsuishi, I.; Ezoe, Y.; Ishikawa, K.; Ohashi, T.; Fujimoto, R.; Mitsuda, K.; Tsunematsu, S.; Yoshida, S.; Kanao, K.; Murakami, M.; DiPirro, M.; Shirron, P.

    2014-11-01

    The sixth X-ray Japanese astronomy satellite, namely Astro-H, will be launched in 2015. The Soft X-ray Spectrometer onboard the Astro-H is a 6 × 6 X-ray microcalorimeter array and provides us with both a high energy resolution of cryocoolers, a 30-L superfluid helium cryostat, and a 3-stage adiabatic demagnetization refrigerator are utilized. A very small heat load up to ∼0.9 mW on the helium tank is allowable to realize the helium lifetime of >3 years, which consequently requires that the vapor flow rate out of the helium tank should be very small helium under zero gravity and safely vent the small amount of the helium vapor. We measured helium mass flow rates from the helium tank equipped in the engineering model dewar. We tilted the dewar at an angle of 75° so that one side of the porous plug located at the top of the helium tank attaches the liquid helium and the porous plug separates the liquid and vapor helium by thermomechanical effect. Helium mass flow rates were measured at helium tank temperatures of 1.3, 1.5 and 1.9 K. We confirmed that resultant mass flow rates are in good agreement within the systematic error or low compared to component test results and achieve all the requirements. The film flow suppression also worked normally. Therefore, we concluded that the SXS helium vent system satisfactorily performs integrated into the dewar.

  9. High pressure, high strain rate material strength studies

    Science.gov (United States)

    Remington, B. A.; Arsenlis, A.; Barton, N.; Belof, J.; Cavallo, R.; Maddox, B.; Park, H.-S.; Prisbrey, S.; Rudd, R.; Comley, A.; Meyers, M.; Wark, J.

    2011-10-01

    Constitutive models for material strength are currently being tested at high pressures by comparing 2D simulations with experiments measuring the Rayleigh-Taylor (RT) instability evolution in solid-state samples of vanadium (V), tantalum (Ta), and iron (Fe). The multiscale strength models being tested combine molecular dynamics, dislocation dynamics, and continuum simulations. Our analysis for the V experiments suggests that the material deformation at these conditions falls into the phonon drag regime, whereas for Ta, the deformation resides mainly in the thermal activation regime. Recent Fe-RT experiments suggest perturbation growth about the alpha-epsilon (bcc-hcp) phase transition threshold has been observed. Using the LLNL multiscale models, we decompose the strength as a function of strain rate into its dominant components of thermal activation, phonon drag, and work hardening. We have also developed a dynamic diffraction diagnostic technique to measure strength directly from shock compressed single crystal samples. Finally, recovery experiments allow a comparison of residual dislocation density with predictions from the multiscale model. This work performed under the auspices of the U.S. DoE by LLNL Security, LLC under Contract DE-AC52-07NA27344.

  10. How does transient storage change as a function of valley position and flow rate?

    Science.gov (United States)

    Ward, A. S.; Gooseff, M. N.; Bencala, K. E.; Payn, R. A.; Wondzell, S. M.; Kelleher, C.; Wagener, T.

    2011-12-01

    Stream and river networks provide the spatial structure for flow and transport. Relationships of discharge and stream velocity to stream network position have been well-studied. However, we lack understanding of the relationship between transient storage and stream network position. Here we present results of conservative solute tracer studies (sodium chloride slug additions) completed along 2.6-km of stream reach at 100-m intervals. Four series of tracer tests were performed during high, two intermediate, and low baseflow conditions. We used observed solute transport data to calculate net and gross gains and losses for each study reach, and used Monte Carlo methods to characterize transient storage model parameters and uncertainty for 106 individual tracer injections. Stream area and dispersion decreased along the stream network from outlet to headwaters, while transient storage area and exchange coefficient showed no spatial trend. Area was the best resolved parameter, followed by dispersion. Storage area and exchange coefficient parameters were highly uncertain under all flow conditions at all locations, with interquartile ranges for the top 0.5% of parameter sets spanning orders of magnitude. Uncertainty in storage area and exchange rate overwhelms any spatial organization of these parameters. Results demonstrate the disparity between gross exchanges of water across the streambed (i.e., channel water balance, quantified by mass lost) and transient storage of solutes along the stream-hyporheic network (quantified by mass recovered).

  11. High-Rate Capable Floating Strip Micromegas

    CERN Document Server

    Bortfeldt, Jonathan; Biebel, Otmar; Danger, Helge; Flierl, Bernhard; Hertenberger, Ralf; Lösel, Philipp; Moll, Samuel; Parodi, Katia; Rinaldi, Ilaria; Ruschke, Alexander; Zibell, André

    2015-01-01

    We report on the optimization of discharge insensitive floating strip Micromegas (MICRO-MEsh GASeous) detectors, fit for use in high-energy muon spectrometers. The suitability of these detectors for particle tracking is shown in high-background environments and at very high particle fluxes up to 60MHz/cm$^2$. Measurement and simulation of the microscopic discharge behavior have demonstrated the excellent discharge tolerance. A floating strip Micromegas with an active area of 48cm$\\times$50cm with 1920 copper anode strips exhibits in 120GeV pion beams a spatial resolution of 50$\\mu$m at detection efficiencies above 95%. Pulse height, spatial resolution and detection efficiency are homogeneous over the detector. Reconstruction of particle track inclination in a single detector plane is discussed, optimum angular resolutions below $5^\\circ$ are observed. Systematic deviations of this $\\mu$TPC-method are fully understood. The reconstruction capabilities for minimum ionizing muons are investigated in a 6.4cm$\\time...

  12. Experimental investigation on a high subsonic compressor cascade flow

    Directory of Open Access Journals (Sweden)

    Zhang Haideng

    2015-08-01

    Full Text Available With the aim of deepening the understanding of high-speed compressor cascade flow, this paper reports an experimental study on NACA-65 K48 compressor cascade with high subsonic inlet flow. With the increase of passage pressurizing ability, endwall boundary layer behavior is deteriorated, and the transition zone is extended from suction surface to the endwall as the adverse pressure gradient increases. Cross flow from endwall to midspan, mixing of corner boundary layer and the main stream, and reversal flow on the suction surface are caused by corner separation vortex structures. Passage vortex is the main corner separation vortex. During its movement downstream, the size grows bigger while the rotating direction changes, forming a limiting circle. With higher incidence, corner separation is further deteriorated, leading to higher flow loss. Meanwhile, corner separation structure, flow mixing characteristics and flow loss distribution vary a lot with the change of incidence. Compared with low aspect-ratio model, corner separation of high aspect-ratio model moves away from the endwall and is more sufficiently developed downstream the cascade. Results obtained present details of high-speed compressor cascade flow, which is rare in the relating research fields and is beneficial to mechanism analysis, aerodynamic optimization and flow control design.

  13. Effects of flow rate and temperature on cyclic gas exchange in tsetse flies (Diptera, Glossinidae).

    Science.gov (United States)

    Terblanche, John S; Chown, Steven L

    2010-05-01

    Air flow rates may confound the investigation and classification of insect gas exchange patterns. Here we report the effects of flow rates (50, 100, 200, 400 ml min(-1)) on gas exchange patterns in wild-caught Glossina morsitans morsitans from Zambia. At rest, G. m. morsitans generally showed continuous or cyclic gas exchange (CGE) but no evidence of discontinuous gas exchange (DGE). Flow rates had little influence on the ability to detect CGE in tsetse, at least in the present experimental setup and under these laboratory conditions. Importantly, faster flow rates resulted in similar gas exchange patterns to those identified at lower flower rates suggesting that G. m. morsitans did not show DGE which had been incorrectly identified as CGE at lower flow rates. While CGE cycle frequency was significantly different among the four flow rates (prate treatment variation. Using a laboratory colony of closely related, similar-sized G. morsitans centralis we subsequently investigated the effects of temperature, gender and feeding status on CGE pattern variation since these factors can influence insect metabolic rates. At 100 ml min(-1) CGE was typical of G. m. centralis at rest, although it was significantly more common in females than in males (57% vs. 43% of 14 individuals tested per gender). In either sex, temperature (20, 24, 28 and 32 degrees C) had little influence on the number of individuals showing CGE. However, increases in metabolic rate with temperature were modulated largely by increases in burst volume and cycle frequency. This is unusual among insects showing CGE or DGE patterns because increases in metabolic rate are usually modulated by increases in frequency, but either no change or a decline in burst volume.

  14. High dose rate brachytherapy source measurement intercomparison.

    Science.gov (United States)

    Poder, Joel; Smith, Ryan L; Shelton, Nikki; Whitaker, May; Butler, Duncan; Haworth, Annette

    2017-06-01

    This work presents a comparison of air kerma rate (AKR) measurements performed by multiple radiotherapy centres for a single HDR (192)Ir source. Two separate groups (consisting of 15 centres) performed AKR measurements at one of two host centres in Australia. Each group travelled to one of the host centres and measured the AKR of a single (192)Ir source using their own equipment and local protocols. Results were compared to the (192)Ir source calibration certificate provided by the manufacturer by means of a ratio of measured to certified AKR. The comparisons showed remarkably consistent results with the maximum deviation in measurement from the decay-corrected source certificate value being 1.1%. The maximum percentage difference between any two measurements was less than 2%. The comparisons demonstrated the consistency of well-chambers used for (192)Ir AKR measurements in Australia, despite the lack of a local calibration service, and served as a valuable focal point for the exchange of ideas and dosimetry methods.

  15. Impact of gas flow rate on breakdown of filamentary dielectric barrier discharges

    Science.gov (United States)

    Höft, H.; Becker, M. M.; Kettlitz, M.

    2016-03-01

    The influence of gas flow rate on breakdown properties and stability of pulsed dielectric barrier discharges (DBDs) in a single filament arrangement using a gas mixture of 0.1 vol. % O2 in N2 at atmospheric pressure was investigated by means of electrical and optical diagnostics, accompanied by fluid dynamics and electrostatics simulations. A higher flow rate perpendicular to the electrode symmetry axis resulted in an increased breakdown voltage and DBD current maximum, a higher discharge inception jitter, and a larger emission diameter of the discharge channel. In addition, a shift of the filament position for low gas flow rates with respect to the electrode symmetry axis was observed. These effects can be explained by the change of the residence time of charge carriers in the discharge region—i.e., the volume pre-ionization—for changed flow conditions due to the convective transport of particles out of the center of the gap.

  16. Modeling Flow Rate to Estimate Hydraulic Conductivity in a Parabolic Ceramic Water Filter

    Directory of Open Access Journals (Sweden)

    Ileana Wald

    2012-01-01

    Full Text Available In this project we model volumetric flow rate through a parabolic ceramic water filter (CWF to determine how quickly it can process water while still improving its quality. The volumetric flow rate is dependent upon the pore size of the filter, the surface area, and the height of water in the filter (hydraulic head. We derive differential equations governing this flow from the conservation of mass principle and Darcy's Law and find the flow rate with respect to time. We then use methods of calculus to find optimal specifications for the filter. This work is related to the research conducted in Dr. James R. Mihelcic's Civil and Environmental Engineering Lab at USF.

  17. Groundwater flow analysis and dose rate estimates from releases to wells at a coastal site

    Energy Technology Data Exchange (ETDEWEB)

    Kattilakoski, E.; Suolanen, V. [VTT Energy, Espoo (Finland)

    2000-09-01

    In the groundwater flow modelling part of this work the effective dilution volume in the well scenario was estimated by means of transient simulations of groundwater flow and transport, which are coupled due to the varying salinity. Both deep, drilled wells and shallow surface wells in the vicinity of the repository were considered. The simulations covered the time period from the present to 1000 years after the present. Conceptually the fractured bedrock consists of planar fracture zones (with a high fracture density and a greater ability to conduct water) and the intact rock (in which the fracture density and the hydraulic conductivity are low). For them the equivalent-continuum model was applied separately. Thus, the fractured bedrock was considered as piecewise homogeneous (except for the depth dependence) and isotropic continuum with representative average characteristics. A generic simulation model for groundwater flow and solute transport was developed on the basis of geological, hydrogeological and hydrogeochemical data at a coastal area. The simulation model contains all the data necessary for the numerical simulations, i.e. the groundwater table and topography, salinity, the postglacial land uplift and sea level rise, the conceptual geometry of fracture zones, the hydraulic properties of the bedrock as well as the description of the modelling volume. The model comprises an area of about 26 km{sup 2}. It covers an island and the surrounding sea. The finite element code FEFTRA (formerly known as FEFLOW) was used in this work for the numerical solution. The channelling along the flow routes was found to be critical for the resulting in a well. A deep well may extend near the area of the deep flow routes, but in order to get flow routes into a shallow well, it has to be placed in the immediate vicinity of the discharge areas. According to the groundwater flow analyses the effective dilution volume of the well seems to vary from 30 000 m{sup 3}/a to 460 000 m

  18. Fabrication of microfluidic architectures for optimal flow rate and concentration measurement for lab on chip application

    Science.gov (United States)

    Adam, Tijjani; Hashim, U.

    2017-03-01

    Optimum flow in micro channel for sensing purpose is challenging. In this study, The optimizations of the fluid sample flows are made through the design and characterization of the novel microfluidics' architectures to achieve the optimal flow rate in the micro channels. The biocompatibility of the Polydimetylsiloxane (Sylgard 184 silicon elastomer) polymer used to fabricate the device offers avenue for the device to be implemented as the universal fluidic delivery system for bio-molecules sensing in various bio-medical applications. The study uses the following methodological approaches, designing a novel microfluidics' architectures by integrating the devices on a single 4 inches silicon substrate, fabricating the designed microfluidic devices using low-cost solution soft lithography technique, characterizing and validating the flow throughput of urine samples in the micro channels by generating pressure gradients through the devices' inlets. The characterization on the urine samples flow in the micro channels have witnessed the constant flow throughout the devices.

  19. Liquid argon calorimeter performance at high rates

    CERN Document Server

    Seifert, F; The ATLAS collaboration

    2012-01-01

    The expected increase of luminosity at HL-LHC by a factor of ten with respect to LHC luminosities has serious consequences for the signal reconstruction, radiation hardness requirements and operations of the ATLAS liquid argon calorimeters in the endcap, respectively forward region. Small modules of each type of calorimeter have been built and exposed to a high intensity proton beam of 50 GeV at IHEP/Protvino. The beam is extracted via the bent crystal technique, offering the unique opportunity to cover intensities ranging from $10^6$ p/s up to $10^{12}$ p/s. This exceeds the deposited energy per time expected at HL-LHC by more than a factor of 100. The correlation between beam intensity and the read-out signal has been studied. The data show clear indications of pulse shape distortion due to the high ionization build-up, in agreement with MC expectations. This is also confirmed from the dependence of the HV currents on beam intensity.

  20. Liquid Argon Calorimeter performance at High Rates

    CERN Document Server

    Seifert, F; The ATLAS collaboration

    2013-01-01

    The expected increase of luminosity at HL-LHC by a factor of ten with respect to LHC luminosities has serious consequences for the signal reconstruction, radiation hardness requirements and operations of the ATLAS liquid argon calorimeters in the endcap, respectively forward region. Small modules of each type of calorimeter have been built and exposed to a high intensity proton beam of 50 GeV at IHEP/Protvino. The beam is extracted via the bent crystal technique, offering the unique opportunity to cover intensities ranging from $10^6$ p/s up to $3\\cdot10^{11}$ p/s. This exceeds the deposited energy per time expected at HL-LHC by more than a factor of 100. The correlation between beam intensity and the read-out signal has been studied. The data show clear indications of pulse shape distortion due to the high ionization build-up, in agreement with MC expectations. This is also confirmed from the dependence of the HV currents on beam intensity.

  1. High temperature flow behaviour of SiC reinforced lithium aluminosilicate composites

    Indian Academy of Sciences (India)

    Santanu Das; V S R Murthy; G S Murty

    2001-04-01

    The compressive flow behaviour of lithium aluminosilicate (LAS) glass, with and without SiC particulate reinforcements, was studied. The LAS glass crystallized to spodumene during high-temperature testing. The flow behaviour of LAS glass changed from Newtonian to non-Newtonian due to the presence of crystalline phase. Further, with the addition of 40 vol.% SiC additions, the strain rate sensitivity of flow stress decreased. While the activation energy for flow in LAS was 300 kJ/mole, it increased to 995 kJ/mole with the addition of 40 vol.% SiC reinforcements.

  2. High speed digital holographic interferometry for hypersonic flow visualization

    Science.gov (United States)

    Hegde, G. M.; Jagdeesh, G.; Reddy, K. P. J.

    2013-06-01

    Optical imaging techniques have played a major role in understanding the flow dynamics of varieties of fluid flows, particularly in the study of hypersonic flows. Schlieren and shadowgraph techniques have been the flow diagnostic tools for the investigation of compressible flows since more than a century. However these techniques provide only the qualitative information about the flow field. Other optical techniques such as holographic interferometry and laser induced fluorescence (LIF) have been used extensively for extracting quantitative information about the high speed flows. In this paper we present the application of digital holographic interferometry (DHI) technique integrated with short duration hypersonic shock tunnel facility having 1 ms test time, for quantitative flow visualization. Dynamics of the flow fields in hypersonic/supersonic speeds around different test models is visualized with DHI using a high-speed digital camera (0.2 million fps). These visualization results are compared with schlieren visualization and CFD simulation results. Fringe analysis is carried out to estimate the density of the flow field.

  3. High Resolution Simulation of Turbulent Flow in a Channel.

    Science.gov (United States)

    1987-09-25

    chosen to maintain the original Poiseuille flow . The introduction of highly unstable disturbances causes transition to turbulence so that the wall...for Turbulent Channel Flow ," Phys. Rev. Lett, Vol. 47, 832-835 (1981). 2. S.A. Orszag and L.C. Kells, "Transition to turbulence in plane Poiseuille and...plane Couette Flow ," J. Fluid Mech., Vol. 96, pp. 159-205. 3. Kreplin, H.-P. and Eckelmann, H., "Behavior of the Three Fluctucting Velocity

  4. High-speed flow visualization in hypersonic, transonic, and shock tube flows

    Science.gov (United States)

    Kleine, H.; Olivier, H.

    2017-02-01

    High-speed flow visualisation has played an important role in the investigations conducted at the Stoßwellenlabor of the RWTH Aachen University for many decades. In addition to applying the techniques of high-speed imaging, this laboratory has been actively developing new or enhanced visualisation techniques and approaches such as various schlieren methods or time-resolved Mach-Zehnder interferometry. The investigated high-speed flows are inherently highly transient, with flow Mach numbers ranging from about M = 0.7 to M = 8. The availability of modern high-speed cameras has allowed us to expand the investigations into problems where reduced reproducibility had so far limited the amount of information that could be extracted from a limited number of flow visualisation records. Following a brief historical overview, some examples of recent studies are given, which represent the breadth of applications in which high-speed imaging has been an essential diagnostic tool to uncover the physics of high-speed flows. Applications include the stability of hypersonic corner flows, the establishment of shock wave systems in transonic airfoil flow, and the complexities of the interactions of shock waves with obstacles of various shapes.

  5. The modern high rate digital cassette recorder

    Science.gov (United States)

    Clemow, Martin

    1993-01-01

    The magnetic tape recorder has played an essential role in the capture and storage of instrumentation data for more than thirty years. During this time, data recording technology has steadily progressed to meet user demands for more channels, wider bandwidths, and longer recording durations. When acquisition and processing moved from analog to digital techniques, so recorder design followed suit. Milestones marking the evolution of the data recorder through these various stages - multi-track analog, high density longitudinal digital, and more recently rotary digital - have often represented important breakthroughs in the handling of ever-greater quantities of data. Throughout this period there has been a very clear line of demarcation between data storage methods in the 'instrumentation world' on the one hand and the 'computer peripheral world' on the other. This is despite the fact that instrumentation data, whether analog or digital at the point of acquisition, is now likely to be processed on a digital computer at some stage. Regardless of whether the processing device is a small personal computer, a workstation, or the largest supercomputer, system integrators have traditionally been faced with the same basic problem - how to interface what is essentially a manually controlled, continuously running device (the tape recorder) into the fast start/stop computer environment without resorting to an excessive amount of complex custom interfacing and performance compromise. The increasing availability of affordable high power processing equipment throughout the scientific world is forcing recorder manufacturers to make their latest and perhaps most important breakthrough - the computer-friendly data recorder. The operating characteristics of such recorders are discussed and the resultant impact on both data acquisition and data analysis elements of system configuration are considered.

  6. Characterisation of DLC films deposited using titanium isopropoxide (TIPOT) at different flow rates.

    Science.gov (United States)

    Said, R; Ali, N; Ghumman, C A A; Teodoro, O M N D; Ahmed, W

    2009-07-01

    In recent years, there has been growing interest in the search for advanced biomaterials for biomedical applications, such as human implants and surgical cutting tools. It is known that both carbon and titanium exhibit good biocompatibility and have been used as implants in the human body. It is highly desirable to deposit biocompatible thin films onto a range of components in order to impart biocompatibility and to minimise wear in implants. Diamond like carbon (DLC) is a good candidate material for achieving biocompatibility and low wear rates. In this study, thin films of diamond-like-carbon DLC were deposited onto stainless steel (316) substrates using C2H2, argon and titanium isopropoxide (TIPOT) precursors. Argon was used to generate the plasma in the plasma enhanced vapour deposition (PECVD) system. A critical coating feature governing the performance of the component during service is film thickness. The as-grown films were in the thickness range 90-100 nm and were found to be dependent on TIPOT flow rate. Atomic force microscopy (AFM) was used to characterise the surface roughness of the samples. As the flow rate of TIPOT increased the average roughness was found to increase in conjunction with the film thickness. Raman spectroscopy was used to investigate the chemical structure of amorphous carbon matrix. Surface tension values were calculated using contact angle measurements. In general, the trend of the surface tension results exhibited an opposite trend to that of the contact angle. The elemental composition of the samples was characterised using a VG ToF SIMS (IX23LS) instrument and X-ray photoelectron spectroscopy (XPS). Surprisingly, SIMS and XPS results showed that the DLC samples did not show evidence of titanium since no peaks representing to titanium appeared on the SIMS/XPS spectra.

  7. Effects of oxygen flow rate on the electrical stability of zinc oxynitride thin-film transistors

    Science.gov (United States)

    Kim, Dae-Hwan; Jeong, Hwan-Seok; Jeong, Chan-Yong; Song, Sang-Hun; Kwon, Hyuck-In

    2017-02-01

    We investigated the effects of the oxygen flow rate (OFR) during the deposition of a zinc oxynitride (ZnON) channel layer on the electrical performance and stability of high-mobility ZnON thin-film transistors (TFTs). The ZnON TFTs prepared at a lower OFR exhibited higher electrical performance characteristics and a higher electrical stability under positive gate bias stresses than those prepared at a higher OFR, but showed a lower electrical stability under negative gate bias stresses. The lower density of subgap states within the channel layer and the higher hole concentration due to the small bandgap were considered as physical mechanisms responsible for the observed phenomena, respectively.

  8. A Tale of Tails: Photon Rates and Flow in Ultra-Relativistic Heavy Ion Collisions

    CERN Document Server

    McLerran, Larry

    2015-01-01

    We consider the possibility that quark and gluon distributions in the medium created in high energy heavy ion collisions may be modified by a power law tail at energies much higher than the temperature. We parametrize such a tail by Tsallis distributions with an exponent motivated by phenomenology. These distributions are characterized by an effective temperature scale that we assume to evolve in time like the temperature for thermal distributions. We find that including such a tail increases the rates for photon production and significantly delays the emission times for photons of a fixed energy. We argue that these effects are sufficiently large that they should be able to account for photon yields and flow patterns seen in LHC and RHIC experiments.

  9. Effect of silane flow rate on structural, electrical and optical properties of silicon thin films grown by VHF PECVD technique

    Energy Technology Data Exchange (ETDEWEB)

    Gope, Jhuma [Physics of Energy Harvesting Division, CSIR-Network of Institutes for Solar Energy, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India); Department of Physics, Banaras Hindu University, Varanasi 221005 (India); Kumar, Sushil, E-mail: skumar@nplindia.org [Physics of Energy Harvesting Division, CSIR-Network of Institutes for Solar Energy, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India); Sudhakar, S.; Rauthan, C.M.S. [Physics of Energy Harvesting Division, CSIR-Network of Institutes for Solar Energy, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi 110012 (India); Srivastava, P.C. [Department of Physics, Banaras Hindu University, Varanasi 221005 (India)

    2013-08-15

    Hydrogenated silicon thin films deposited by VHF PECVD process for various silane flow rates have been investigated. The silane flow rate was varied from 5 sccm to 30 sccm, maintaining all other parameters constant. The electrical, structural and optical properties of these films were systematically studied as a function of silane flow rate. These films were characterized by Raman spectroscopy, Scanning Electron Microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectroscopy and UV–visible (UV–Vis) spectroscopy. Different crystalline volume fraction (22%–60%) and band gap (∼1.58 eV–∼1.96 eV) were achieved for silicon thin films by varying the silane concentration. A transition from amorphous to nanocrystalline silicon has been confirmed by Raman and FTIR analysis. The film grown at this transition region shows the high conductivity in the order of 10{sup −4} Ω{sup −1} cm{sup −1}. - Highlights: • Silicon films grown using VHF PECVD at various F{sub silane} (silane flow rate). • Amorphous to nanocrystalline silicon transition at F{sub silane} ∼5 sccm–10 sccm. • Deposition rate increases with the increase of F{sub silane}. • Powder formation occurred beyond 20 sccm of F{sub silane}. • Film grown at 20 sccm shows max. crystalline fraction ∼60% with E{sub g} ∼1.58 eV.

  10. Influence of chemistry on steam generator primary-to-secondary stabilized low leak flow rate

    Energy Technology Data Exchange (ETDEWEB)

    Hervouet, C.; Pages, D. [EDF R and D (France); Fauchon, C.; Bretelle, J.L. [EDF GDL (France); Bus, F. [EDF DPN (France)

    2002-07-01

    The comparison of the leak flow rate behavior between the previous and the new boron/lithium coordination, the second one corresponding to an higher pH during the cycle than the first one, leads to the following conclusions, confirmed by the experimental and theoretical studies: Low leak flow rate is extremely sensitive to pH in the zone of pH of primary water because the behavior of metallic oxide is changing drastically in that range of pH (from precipitation to dissolution); Leak flow rate is often maintained lower with low pH. Let's recall however that pH can not reach a too low value which could enhance corrosion product deposition, increase dose rates along the primary circuit, and lead to reactor outages due to problems on fuel assemblies. The understanding of the governing phenomena led to adapt in 2000 the reactor cooling system chemical conditioning for the French Pressurized Water reactors facing problems with the management of the stabilized leak flow rate fluctuations, once no degradation of tube bundle integrity is proved. Each part of the cycle and operating conditions lead to an advised operating action. In general, the new recommendations for the reactors facing problems with the management of low leak flow rate are based on the principle of helping the precipitation of metallic oxide within the crack and preventing their dissolution. (authors)

  11. Engineering Mathematical Analysis Method for Productivity Rate in Linear Arrangement Serial Structure Automated Flow Assembly Line

    Directory of Open Access Journals (Sweden)

    Tan Chan Sin

    2015-01-01

    Full Text Available Productivity rate (Q or production rate is one of the important indicator criteria for industrial engineer to improve the system and finish good output in production or assembly line. Mathematical and statistical analysis method is required to be applied for productivity rate in industry visual overviews of the failure factors and further improvement within the production line especially for automated flow line since it is complicated. Mathematical model of productivity rate in linear arrangement serial structure automated flow line with different failure rate and bottleneck machining time parameters becomes the basic model for this productivity analysis. This paper presents the engineering mathematical analysis method which is applied in an automotive company which possesses automated flow assembly line in final assembly line to produce motorcycle in Malaysia. DCAS engineering and mathematical analysis method that consists of four stages known as data collection, calculation and comparison, analysis, and sustainable improvement is used to analyze productivity in automated flow assembly line based on particular mathematical model. Variety of failure rate that causes loss of productivity and bottleneck machining time is shown specifically in mathematic figure and presents the sustainable solution for productivity improvement for this final assembly automated flow line.

  12. Acute short-term mental stress does not influence salivary flow rate dynamics.

    Directory of Open Access Journals (Sweden)

    Ella A Naumova

    Full Text Available BACKGROUND: Results of studies that address the influence of stress on salivary flow rate and composition are controversial. The aim of this study was to reveal the influence of stress vulnerability and different phases of stress reactivity on the unstimulated and stimulated salivary flow rate. We examined that acute mental stress does not change the salivary flow rate. In addition, we also examined the salivary cortisol and protein level in relation to acute mental stress stimuli. METHODS: Saliva of male subjects was collected for five minutes before, immediately, 10, 30 and 120 min after toothbrushing. Before toothbrushing, the subjects were exposed to acute stress in the form of a 2 min public speech. Salivary flow rate and total protein was measured. The physiological stress marker cortisol was analyzed using enzyme-linked immunosorbent assay. To determine the subjects' psychological stress reaction, the State-Trait-Anxiety Inventory State questionnaire (STAI data were obtained. The subjects were divided into stress subgroup (S1 (psychological reactivity, stress subgroup (S2 (psychological and physiological reactivity and a control group. The area under the curve for salivarycortisol concentration and STAI-State scores were calculated. All data underwent statistical analysis using one-way analysis of variance. RESULTS: Immediately after stress exposure, all participants exhibited a psychological stress reaction. Stress exposure did not change the salivary flow rate. Only 69% of the subjects continued to display a physiological stress reaction 20 minutes after the public talk. There was no significant change in the salivary flow rate during the psychological and the physiological stress reaction phases relative to the baseline. CONCLUSIONS: Acute stress has no impact on the salivary flow rate; however, there may be other responses through salivary proteins that are increased with the acute stress stimuli. Future studies are needed to examine

  13. High energy density redox flow device

    Energy Technology Data Exchange (ETDEWEB)

    Carter, W. Craig; Chiang, Yet-Ming; Duduta, Mihai; Limthongkul, Pimpa

    2017-04-04

    Redox flow devices are described including a positive electrode current collector, a negative electrode current collector, and an ion-permeable membrane separating said positive and negative current collectors, positioned and arranged to define a positive electroactive zone and a negative electroactive zone; wherein at least one of said positive and negative electroactive zone comprises a flowable semi-solid composition comprising ion storage compound particles capable of taking up or releasing said ions during operation of the cell, and wherein the ion storage compound particles have a polydisperse size distribution in which the finest particles present in at least 5 vol % of the total volume, is at least a factor of 5 smaller than the largest particles present in at least 5 vol % of the total volume.

  14. High data rate optical transceiver terminal

    Science.gov (United States)

    Clarke, E. S.

    1973-01-01

    The objectives of this study were: (1) to design a 400 Mbps optical transceiver terminal to operate from a high-altitude balloon-borne platform in order to permit the quantitative evaluation of a space-qualifiable optical communications system design, (2) to design an atmospheric propagation experiment to operate in conjunction with the terminal to measure the degrading effects of the atmosphere on the links, and (3) to design typical optical communications experiments for space-borne laboratories in the 1980-1990 time frame. As a result of the study, a transceiver package has been configured for demonstration flights during late 1974. The transceiver contains a 400 Mbps transmitter, a 400 Mbps receiver, and acquisition and tracking receivers. The transmitter is a Nd:YAG, 200 Mhz, mode-locked, CW, diode-pumped laser operating at 1.06 um requiring 50 mW for 6 db margin. It will be designed to implement Pulse Quaternary Modulation (PQM). The 400 Mbps receiver utilizes a Dynamic Crossed-Field Photomultiplier (DCFP) detector. The acquisition receiver is a Quadrant Photomultiplier Tube (QPMT) and receives a 400 Mbps signal chopped at 0.1 Mhz.

  15. FLUVIAL PROCESSES AND SEDIMENT SCOUR RATE OF THE YELLOW RIVER UNDER ACTION OF UNSTEADY FLOWS

    Institute of Scientific and Technical Information of China (English)

    Yong-Nian XU; Zhi-Yong LIANG; Zhao-Yin WANG

    2001-01-01

    Riverbed scour of the main channel by floods in the Yellow River and its tributaries was investigated, including scour by hyper-concentrated floods. Flood scour usually causes variation of river cross-sections in a way similar to that occured when the sediment inflow is less than the sediment-laden capacity. Scour rate equation for the main channel derived based on the momentum and continuous equations was verified by field data. This equation indicates that unsteady flow scour rate is proportional to the flow density, the velocity of the flood peak, the rising rate of flow discharge per unit width, and so on. The Maximum scour depth after a flood could be predicted by the scour rate equation proposed in this paper.

  16. Effect of Various Sugary Beverages on Salivary pH, Flow Rate, and Oral Clearance Rate amongst Adults.

    Science.gov (United States)

    Hans, Rinki; Thomas, Susan; Garla, Bharat; Dagli, Rushabh J; Hans, Manoj Kumar

    2016-01-01

    Introduction. Diet is a major aetiological factor for dental caries and enamel erosion. This study was undertaken with the aim of assessing the effect of selected locally available beverages on salivary pH, flow rate, and oral clearance rate amongst adults. Materials and Method. This clinical trial comprised 120 subjects. Test beverages undertaken were pepsi, fruit drink, coffee, and sweetened milk. Statistical analysis was carried out using SPSS version 17. Descriptive statistics, one-way ANOVA, and post hoc Tukey's test were applied in the statistical tests. Results. It was found that salivary pH decreased for all the beverages immediately after consumption and the salivary flow rate increased after their consumption. The oral clearance rate of sweetened milk was found to be the least at 6.5 minutes and that of pepsi was found to be 13 minutes. However, the oral clearance rates of fruit drink and coffee were found to be equal at 15 minutes. Conclusion. Although it was found out that liquids cleared rapidly from the oral cavity, they had a significant cariogenic and erosive potential. Hence, it is always advised to minimise the consumption of beverages, especially amongst children and young adults to maintain a good oral health.

  17. Effect of Various Sugary Beverages on Salivary pH, Flow Rate, and Oral Clearance Rate amongst Adults

    Directory of Open Access Journals (Sweden)

    Rinki Hans

    2016-01-01

    Full Text Available Introduction. Diet is a major aetiological factor for dental caries and enamel erosion. This study was undertaken with the aim of assessing the effect of selected locally available beverages on salivary pH, flow rate, and oral clearance rate amongst adults. Materials and Method. This clinical trial comprised 120 subjects. Test beverages undertaken were pepsi, fruit drink, coffee, and sweetened milk. Statistical analysis was carried out using SPSS version 17. Descriptive statistics, one-way ANOVA, and post hoc Tukey’s test were applied in the statistical tests. Results. It was found that salivary pH decreased for all the beverages immediately after consumption and the salivary flow rate increased after their consumption. The oral clearance rate of sweetened milk was found to be the least at 6.5 minutes and that of pepsi was found to be 13 minutes. However, the oral clearance rates of fruit drink and coffee were found to be equal at 15 minutes. Conclusion. Although it was found out that liquids cleared rapidly from the oral cavity, they had a significant cariogenic and erosive potential. Hence, it is always advised to minimise the consumption of beverages, especially amongst children and young adults to maintain a good oral health.

  18. Modeling of high speed micro rotors in moderate flow confinement

    NARCIS (Netherlands)

    Dikmen, E.; Hoogt, van der P.J.M.; Aarts, R.G.K.M.

    2008-01-01

    The recent developments in high speed micro rotating machinery lead to the need for multiphysical modeling of the rotor and the surrounding medium. In this study, thermal and flow induced effects on rotor dynamics of geometries with moderate flow confinement are studied. The structure is modeled via

  19. Tracheal compliance and limit flow rate changes in a murine model of asthma

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Trachea is the unique passage for air to flow in and out. Its tone is of importance for the respiration system. However, investigation on how tracheal tone changes due to asthma is limited. Aiming at studying how the mechanical property changes due to asthma as well as the compliance and flow limitation, the following methods are adopted. Static and passive pressure-volume tests of rats’ trachea of the asthmatic and control groups are carried out and a new type of tube law is formulated to fit the experimental data, based on which changes of compliance and limit flow rate are investigated. In order to give explanation to such changes, histological examinations with tracheal soft tissues are made. The results show that compliance, limit flow rate and material constants included in the tube law largely depend on the longitudinal stretching ratio. Compared with the control group, the tracheal compliance of asthmatic animals decreases significantly, which results in an increased limit flow rate. Histological studies indicate that asthma can lead to hyperplasia/hypertrophy of smooth muscle cells, and increase elastin and collagen fibres in the muscular membrane. Though decreasing compliance increases sta- bility, during the onset of asthma, limit flow rate is much smaller due to the lower transmural pressure. Asthma leads to a stiffer trachea and the obtained results reveal some aspects relevant to asthma-induced tracheal remodelling.

  20. Tracheal compliance and limit flow rate changes in a urine model of asthma

    Institute of Scientific and Technical Information of China (English)

    TENG ZhongZhao; WANG YiQin; LI FuFeng; YAN HaiXia; LIU ZhaoRong

    2008-01-01

    Trachea is the unique passage for air to flow in and out. Its tone is of importance for the respiration system. However, investigation on how tracheal tone changes due to asthma is limited. Aiming at studying how the mechanical property changes due to asthma as well as the compliance and flow limitation, the following methods are adopted. Static and passive pressure-volume tests of rats' trachea of the asthmatic and control groups are carried out and a new type of tube law is formulated to fit the experimental data, based on which changes of compliance and limit flow rate are investigated. In order to give explanation to such changes, histological examinations with tracheal soft tissues are made. The results show that compliance, limit flow rate and material constants included in the tube law largely depend on the longitudinal stretching ratio. Compared with the control group, the tracheal compliance of asthmatic animals decreases significantly, which results in an increased limit flow rate. Histological studies indicate that asthma can lead to hyperplasia/hypertrophy of smooth muscle cells, and increase elastin and collagen fibres in the muscular membrane. Though decreasing compliance increases sta-bility, during the onset of asthma, limit flow rate is much smaller due to the lower transmural pressure. Asthma leads to a stiffer trachea and the obtained results reveal some aspects relevant to asthma-induced tracheal remodelling.

  1. Characterization of fractured reservoirs using tracer and flow-rate data

    Science.gov (United States)

    Juliusson, Egill; Horne, Roland N.

    2013-05-01

    This article introduces a robust method for characterizing fractured reservoirs using tracer and flow-rate data. The flow-rate data are used to infer the interwell connectivity matrix, which describes how injected fluids are divided between producers in the reservoir. The tracer data are used to find a function called the tracer kernel for each injector-producer connection. The tracer kernel describes the volume and dispersive properties of the interwell flow path. A combination of parametric and nonparametric regression methods was developed to estimate the tracer kernels in situations where data are collected at variable flow rate or variable-injected concentration conditions. This characterization method was developed to describe enhanced geothermal systems, although it works well in general for characterizing incompressible flow in fractured reservoirs (e.g., geothermal, carbon sequestration, radioactive waste and waterfloods of oil fields) where transverse dispersivity can be considered negligible and production takes place at constant bottomhole pressure conditions. The inferred metrics can be used to sketch informative field maps and predict tracer breakthrough curves at variable flow-rate conditions.

  2. Mechanism for measurement of flow rate of cerebrospinal fluid in hydrocephalus shunts.

    Science.gov (United States)

    Rajasekaran, Sathish; Kovar, Spencer; Qu, Peng; Inwald, David; Williams, Evan; Qu, Hongwei; Zakalik, Karol

    2014-01-01

    The measurement of the flow rate of cerebrospinal fluid (CSF) or existence of CSF flow inside the shunt tube after shunt implant have been reported as tedious process for both patients and doctors; this paper outlines a potential in vitro flow rate measurement method for CSF in the hydrocephalus shunt. The use of implantable titanium elements in the shunt has been proposed to allow for an accurate temperature measurement along the shunt for prediction of CSF flow rate. The CSF flow velocity can be deduced by decoupling the thermal transfer in the measured differential time at a pair of measurement spots of the titanium elements. Finite element analyses on the fluidic and thermal behaviors of the shunt system have been conducted. Preliminary bench-top measurements on a simulated system have been carried out. The measured flow rates, ranging from 0.5 mm/sec to 1.0 mm/sec, which is clinically practical, demonstrate good agreements with the simulation results.

  3. On rating curve variability in presence of movable bed and unsteady flow. Applications to Tuscan rivers.

    Science.gov (United States)

    Minatti, Lorenzo; Nicoletta De Cicco, Pina; Paris, Enio

    2014-05-01

    In common engineering practice, rating curves are obtained from direct stage-discharge measurements or, more often, from stage measurements coupled with flow simulations. The present work mainly focuses on the latter technique, where stage-measuring gauges are usually installed on bridges with flow conditions likely to be influenced by local geometry constraints. In such cases, backwater flow and flow transition to supercritical state may occur, influencing sediment transport capacity and triggering more intense changes in river morphology. The unsteadiness of the flow hydrograph may play an important role too, according to the velocity of its rising and falling limbs. Nevertheless, the simulations conducted to build a rating curve are often carried out with steady flow and fixed bed conditions where the afore-mentioned effects are not taken into account at all. Numerical simulations with mobile bed and different unsteady flow conditions have been conducted on some real case studies in the rivers of Tuscany (Italy), in order to assess how rating curves change with respect to the "standard" one (that is, the classical steady flow rating curve). A 1D finite volume numerical model (REMo, River Evolution Modeler) has been employed for the simulations. The model solves the 1D Shallow Water equations coupled with the sediments continuity equation in composite channels, where the overbanks are treated with fixed bed conditions while the main channel can either aggrade or be scoured. The model employs an explicit scheme with 2nd order accuracy in both space and time: this allows the correct handling of moderately stiff source terms via a local corrector step. Such capability is very important for the applications of the present work as it allows the modelling of abrupt contractions and jumps in bed bottom elevations which often occur near bridges. The outcomes of the simulations are critically analyzed in order to provide a first insight on the conditions inducing

  4. Dryout-type critical heat flux in vertical upward annular flow: effects of entrainment rate, initial entrained fraction and diameter

    Science.gov (United States)

    Wu, Zan; Wadekar, Vishwas; Wang, Chenglong; Sunden, Bengt

    2017-07-01

    This study aims to reveal the effects of liquid entrainment, initial entrained fraction and tube diameter on liquid film dryout in vertical upward annular flow for flow boiling. Entrainment and deposition rates of droplets were included in mass conservation equations to estimate the local liquid film mass flux in annular flow, and the critical vapor quality at dryout conditions. Different entrainment rate correlations were evaluated using flow boiling data of water and organic liquids including n-pentane, iso-octane and R134a. Effect of the initial entrained fraction (IEF) at the churn-to-annular flow transition was also investigated. A transitional Boiling number was proposed to separate the IEF-sensitive region at high Boiling numbers and the IEF-insensitive region at low Boiling numbers. Besides, the diameter effect on dryout vapor quality was studied. The dryout vapor quality increases with decreasing tube diameter. It needs to be pointed out that the dryout characteristics of submillimeter channels might be different because of different mechanisms of dryout, i.e., drying of liquid film underneath long vapor slugs and flow boiling instabilities.

  5. Skeletal blood flow, iliac histomorphometry, and strontium kinetics in osteoporosis: a relationship between blood flow and corrected apposition rate

    Energy Technology Data Exchange (ETDEWEB)

    Reeve, J.; Arlot, M.; Wootton, R.; Edouard, C.; Tellez, M.; Hesp, R.; Green, J.R.; Meunier, P.J.

    1988-06-01

    In 20 untreated patients with idiopathic or postmenopausal osteoporosis, kinetic studies of skeletal blood flow (using /sup 18/F) and bone turnover (using /sup 85/Sr) were combined with dynamic histomorphometry performed on transiliac biopsies taken within 6 weeks of each other. In 8 patients the combined studies were repeated after treatment. A further 5 patients were studied only while receiving treatment. As expected, skeletal blood flow measured by /sup 18/F correlated with an index of /sup 85/Sr uptake into the exchangeable pools of bone. Additionally and independently, skeletal blood flow correlated with an index of the work rate of the osteoblasts in each multicellular unit of bone (the corrected apposition rate of Parfitt). These correlations were statistically significant in both the untreated patients (P less than 0.05) and the whole group (P less than 0.001). Further indices related to bone turnover at the level of the skeleton as a whole were significantly associated with skeletal blood flow only in the combined group.

  6. Stereoscopic PIV measurements of flow in the nasal cavity with high flow therapy

    Science.gov (United States)

    Spence, C. J. T.; Buchmann, N. A.; Jermy, M. C.; Moore, S. M.

    2011-04-01

    Knowledge of the airflow characteristics within the nasal cavity with nasal high flow (NHF) therapy and during unassisted breathing is essential to understand the treatment's efficacy. The distribution and velocity of the airflow in the nasal cavity with and without NHF cannula flow has been investigated using stereoscopic particle image velocimetry at steady peak expiration and inspiration. In vivo breathing flows were measured and dimensionally scaled to reproduce physiological conditions in vitro. A scaled model of the complete nasal cavity was constructed in transparent silicone and airflow simulated with an aqueous glycerine solution. NHF modifies nasal cavity flow patterns significantly, altering the proportion of inspiration and expiration through each passageway and producing jets with in vivo velocities up to 17.0 ms-1 for 30 l/min cannula flow. Velocity magnitudes differed appreciably between the left and right sides of the nasal cavity. The importance of using a three-component measurement technique when investigating nasal flows has been highlighted.

  7. Flow rate impacts on capillary pressure and interface curvature of connected and disconnected fluid phases during multiphase flow in sandstone

    Science.gov (United States)

    Herring, Anna L.; Middleton, Jill; Walsh, Rick; Kingston, Andrew; Sheppard, Adrian

    2017-09-01

    We investigate capillary pressure-saturation (PC-S) relationships for drainage-imbibition experiments conducted with air (nonwetting phase) and brine (wetting phase) in Bentheimer sandstone cores. Three different flow rate conditions, ranging over three orders of magnitude, are investigated. X-ray micro-computed tomographic imaging is used to characterize the distribution and amount of fluids and their interfacial characteristics. Capillary pressure is measured via (1) bulk-phase pressure transducer measurements, and (2) image-based curvature measurements, calculated using a novel 3D curvature algorithm. We distinguish between connected (percolating) and disconnected air clusters: curvatures measured on the connected phase interfaces are used to validate the curvature algorithm and provide an indication of the equilibrium condition of the data; curvature and volume distributions of disconnected clusters provide insight to the snap-off processes occurring during drainage and imbibition under different flow rate conditions.

  8. The Effect of Minimum Wage Rates on High School Completion

    Science.gov (United States)

    Warren, John Robert; Hamrock, Caitlin

    2010-01-01

    Does increasing the minimum wage reduce the high school completion rate? Previous research has suffered from (1. narrow time horizons, (2. potentially inadequate measures of states' high school completion rates, and (3. potentially inadequate measures of minimum wage rates. Overcoming each of these limitations, we analyze the impact of changes in…

  9. The influence of the gas flow rate during methane biofiltration on an inorganic packing material

    Energy Technology Data Exchange (ETDEWEB)

    Nikiema, J.; Heitz, M. [Sherbrooke Univ., PQ (Canada). Dept. of Chemical Engineering

    2009-02-15

    Sanitary landfills are a major anthropogenic source of methane (CH{sub 4}), an important greenhouse gas (GHG). In 2005, sanitary landfills contributed nearly 25 per cent of the total atmospheric CH{sub 4} emissions in Canada. In order to address this concern, 52 landfills were equipped with gas collection systems in 2005. This study measured the influence of the gas flow rate (GFR) on CH{sub 4} elimination through biofiltration and estimated the maximum level of GFR that allowed conversions within the biofilter above 90 per cent. Since CH{sub 4} biodegrades in the biofilter due to microbial activity, the efficiency of this bioprocess is affected by the number and type of microorganisms present in the biofilter. This study also compared the performance of the biofilter under different gas flow regimes, at two different phosphorus concentrations. The experiments involved the use of a nitrogen minimal salt nutrient solution, for the biofilter periodic irrigation, in which the nitrogen concentration was maintained at 0.75 g/L, while the phosphorus concentration was 1.5 g/L. The objective was to determine if the phosphorus concentration can modify the influence of the GFR on the biofilter. The results showed that the GFR is an important parameter which affects the biofilter performance. It was concluded that the biofiltration process requires a high phosphorus level in the nutrient solution. 23 refs., 2 tabs., 5 figs.

  10. Core surface flow modelling from high-resolution secular variation

    DEFF Research Database (Denmark)

    Holme, R.; Olsen, Nils

    2006-01-01

    -flux hypothesis, but the spectrum of the SV implies that a conclusive test of frozen-flux is not possible. We parametrize the effects of diffusion as an expected misfit in the flow prediction due to departure from the frozen-flux hypothesis; at low spherical harmonic degrees, this contribution dominates...... the expected departure of the SV predictions from flow to the observed SV, while at high degrees the SV model uncertainty is dominant. We construct fine-scale core surface flows to model the SV. Flow non-uniqueness is a serious problem because the flows are sufficiently small scale to allow flow around non......-series of magnetic data and better parametrization of the external magnetic field....

  11. Control of skin blood flow, sweating, and heart rate - Role of skin vs. core temperature

    Science.gov (United States)

    Wyss, C. R.; Brengelmann, G. L.; Johnson, J. M.; Rowell, L. B.; Niederberger, M.

    1974-01-01

    A study was conducted to generate quantitative expressions for the influence of core temperature, skin temperature, and the rate of change of skin temperature on sweat rate, skin blood flow, and heart rate. A second goal of the study was to determine whether the use of esophageal temperature rather than the right atrial temperature as a measure of core temperature would lead to different conclusions about the control of measured effector variables.

  12. ChargeOut! : discounted cash flow compared with traditional machine-rate analysis

    Science.gov (United States)

    Ted Bilek

    2008-01-01

    ChargeOut!, a discounted cash-flow methodology in spreadsheet format for analyzing machine costs, is compared with traditional machine-rate methodologies. Four machine-rate models are compared and a common data set representative of logging skidders’ costs is used to illustrate the differences between ChargeOut! and the machine-rate methods. The study found that the...

  13. Flow "Fine" Synthesis: High Yielding and Selective Organic Synthesis by Flow Methods.

    Science.gov (United States)

    Kobayashi, Shū

    2016-02-18

    The concept of flow "fine" synthesis, that is, high yielding and selective organic synthesis by flow methods, is described. Some examples of flow "fine" synthesis of natural products and APIs are discussed. Flow methods have several advantages over batch methods in terms of environmental compatibility, efficiency, and safety. However, synthesis by flow methods is more difficult than synthesis by batch methods. Indeed, it has been considered that synthesis by flow methods can be applicable for the production of simple gasses but that it is difficult to apply to the synthesis of complex molecules such as natural products and APIs. Therefore, organic synthesis of such complex molecules has been conducted by batch methods. On the other hand, syntheses and reactions that attain high yields and high selectivities by flow methods are increasingly reported. Flow methods are leading candidates for the next generation of manufacturing methods that can mitigate environmental concerns toward sustainable society. © 2015 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  14. Impact of stretching-segment on saturated flow rate of signalized intersection using cellular automation

    Institute of Scientific and Technical Information of China (English)

    李岩; 陈宽民; 过秀成

    2013-01-01

    In order to analyze the impact of stretching-segment on the saturated flow rate of signalized intersection approach, an improved cellular automation model was proposed to estimate its saturated flow rate. The NaSch model was improved by adding different slow probabilities, turning deceleration rules and modified lane changing rules. The relationship between the saturated flow rate of stretching-segments and adjacent lanes was tested in numerical simulation. The length of stretching-segment, cycle length and green time were selected as impact factors of the cellular automation model. The simulation result indicates that the geometrics design of stretching-segment and the traffic signal timing scenario have major effects on the saturated flow rate of the intersection approach. The saturated flow rate will continually increase with increasing stretching-segment length until it reaches a threshold. After reaching the threshold, the stretching-segment can be treated as a separate lane. The green time is approximately linearly related to the threshold length of the stretching-segment. An optimum cycle length exists when the length of the stretching-segment is not long enough, and it is approximately linearly related to the length of stretching-segment.

  15. A Flow Rate Control Approach on Off-Design Analysis of an Organic Rankine Cycle System

    Directory of Open Access Journals (Sweden)

    Ben-Ran Fu

    2016-09-01

    Full Text Available This study explored effects of off-design heat source temperature (TW,in or flow rate (mW on heat transfer characteristics and performance of an organic Rankine cycle system by controlling the flow rate of working fluid R245fa (i.e., the operation flow rate of R245fa was controlled to ensure that R245fa reached saturation liquid and vapor states at the outlets of the preheater and evaporator, respectively. The results showed that the operation flow rate of R245fa increased with TW,in or mW; higher TW,in or mW yielded better heat transfer performance of the designed preheater and required higher heat capacity of the evaporator; heat transfer characteristics of preheater and evaporator differed for off-design TW,in and mW; and net power output increased with TW,in or mW. The results further indicated that the control strategy should be different for various off-design conditions. Regarding maximum net power output, the flow rate control approach is optimal when TW,in or mW exceeds the design point, but the pressure control approach is better when TW,in or mW is lower than the design point.

  16. A joint stochastic-deterministic approach for long-term and short-term modelling of monthly flow rates

    Science.gov (United States)

    Stojković, Milan; Kostić, Srđan; Plavšić, Jasna; Prohaska, Stevan

    2017-01-01

    The authors present a detailed procedure for modelling of mean monthly flow time-series using records of the Great Morava River (Serbia). The proposed procedure overcomes a major challenge of other available methods by disaggregating the time series in order to capture the main properties of the hydrologic process in both long-run and short-run. The main assumption of the conducted research is that a time series of monthly flow rates represents a stochastic process comprised of deterministic, stochastic and random components, the former of which can be further decomposed into a composite trend and two periodic components (short-term or seasonal periodicity and long-term or multi-annual periodicity). In the present paper, the deterministic component of a monthly flow time-series is assessed by spectral analysis, whereas its stochastic component is modelled using cross-correlation transfer functions, artificial neural networks and polynomial regression. The results suggest that the deterministic component can be expressed solely as a function of time, whereas the stochastic component changes as a nonlinear function of climatic factors (rainfall and temperature). For the calibration period, the results of the analysis infers a lower value of Kling-Gupta Efficiency in the case of transfer functions (0.736), whereas artificial neural networks and polynomial regression suggest a significantly better match between the observed and simulated values, 0.841 and 0.891, respectively. It seems that transfer functions fail to capture high monthly flow rates, whereas the model based on polynomial regression reproduces high monthly flows much better because it is able to successfully capture a highly nonlinear relationship between the inputs and the output. The proposed methodology that uses a combination of artificial neural networks, spectral analysis and polynomial regression for deterministic and stochastic components can be applied to forecast monthly or seasonal flow rates.

  17. SONIC SPEED AND SHOCK WAVE IN HIGH VELOCITY AERATED FLOWS FROM HIGH HEAD DISCHARGE STRUCTURES

    Institute of Scientific and Technical Information of China (English)

    Dong Zhi-yong

    2003-01-01

    The compressible characteristics in aerated flows at the high velocity of about 50m/s were analyzed. Based on the theory of compressible the relations between the sonic speed and shock wave in high-velocity aerated flow were theoretically deduced. And comparisons with measured data were made. The theoretical and experimental results show the sonic speed in aerated flow is merely of the order of several-dozen meters per second, and its minimum value is only 20m/s, which is far much less than that in water or air alone. So high subsonic flow, supersonic flow and transonic flow as well as compression wave, shock wave and expansion wave similarly to aerodnamics may be produced in high velocity aerated flow at the speed of the order of 50m/s. Hence the influences of these compressible characteristics on high head discharge structures can not be neglected, especially on super high dams over 200m high.

  18. Optimal power flow calculation for power system with UPFC considering load rate equalization

    Science.gov (United States)

    Liu, Jiankun; Chen, Jing; Zhang, Qingsong

    2017-06-01

    Unified power flow controller (UPFC) device can change system electrical quantity (such as voltage, impedance, phase angle, etc.) rapidly and flexibly under the premise of maintain security, stability and reliability of power system, thus can improve the transmission power and transmission line utilization, so as to enhance the power supply capacity of the power grid. Based on a thorough study of the steady-state model of UPFC, taking load rate equalization as objective function, the optimal power flow model is established with UPFC, and simplified interior point method is used to solve it. Finally, optimal power flow of 24 continuous sections actual data is calculated on a typical day of Nanjing network. The results show that the optimal power flow calculation with UPFC can optimize the load rate equalization on the basis of eliminating line overload, improving the voltage level of local power network.

  19. Flow Rate of Particles through Apertures Obtained from Self-Similar Density and Velocity Profiles

    Science.gov (United States)

    Janda, Alvaro; Zuriguel, Iker; Maza, Diego

    2012-06-01

    “Beverloo’s law” is considered as the standard expression to estimate the flow rate of particles through apertures. This relation was obtained by simple dimensional analysis and includes empirical parameters whose physical meaning is poorly justified. In this Letter, we study the density and velocity profiles in the flow of particles through an aperture. We find that, for the whole range of apertures studied, both profiles are self-similar. Hence, by means of the functionality obtained for them the mass flow rate is calculated. The comparison of this expression with the Beverloo’s one reveals some differences which are crucial to understanding the mechanism that governs the flow of particles through orifices.

  20. Evaporation of polydispersed droplets in a highly turbulent channel flow

    Science.gov (United States)

    Cochet, M.; Bazile, Rudy; Ferret, B.; Cazin, S.

    2009-09-01

    A model experiment for the study of evaporating turbulent two-phase flows is presented here. The study focuses on a situation where pre-atomized and dispersed droplets vaporize and mix in a heated turbulent flow. The test bench consists in a channel flow with characteristics of homogeneous and isotropic turbulence where fluctuations levels reach very high values (25% in the established zone). An ultrasonic atomizer allows the injection of a mist of small droplets of acetone in the carrier flow. The large range diameters ensure that every kind of droplet behavior with regards to turbulence is possible. Instantaneous concentration fields of the vaporized phase are extracted from fluorescent images (PLIF) of the two phase flow. The evolution of the mixing of the acetone vapor is analyzed for two different liquid mass loadings. Despite the high turbulence levels, concentration fluctuations remain significant, indicating that air and acetone vapor are not fully mixed far from the injector.

  1. Evaporation of polydispersed droplets in a highly turbulent channel flow

    Energy Technology Data Exchange (ETDEWEB)

    Cochet, M.; Bazile, Rudy; Ferret, B.; Cazin, S. [INPT, UPS, IMFT (Institut de Mecanique des Fluides de Toulouse), Universite de Toulouse (France)

    2009-09-15

    A model experiment for the study of evaporating turbulent two-phase flows is presented here. The study focuses on a situation where pre-atomized and dispersed droplets vaporize and mix in a heated turbulent flow. The test bench consists in a channel flow with characteristics of homogeneous and isotropic turbulence where fluctuations levels reach very high values (25% in the established zone). An ultrasonic atomizer allows the injection of a mist of small droplets of acetone in the carrier flow. The large range diameters ensure that every kind of droplet behavior with regards to turbulence is possible. Instantaneous concentration fields of the vaporized phase are extracted from fluorescent images (PLIF) of the two phase flow. The evolution of the mixing of the acetone vapor is analyzed for two different liquid mass loadings. Despite the high turbulence levels, concentration fluctuations remain significant, indicating that air and acetone vapor are not fully mixed far from the injector. (orig.)

  2. High regression rate, high density hybrid fuels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR program will investigate high energy density novel nanofuels combined with high density binders for use with an N2O oxidizer. Terves has developed...

  3. Time Decay Rates of the Isotropic Non-Newtonian Flows in Rn

    Institute of Scientific and Technical Information of China (English)

    Bo-Qing Dong

    2007-01-01

    This paper is concerned with time decay rates for weak solutions to a class system of isotropic incompressible non-Newtonian fluid motion in Rn. With the use of the spectral decomposition methods of Stokes operator, the optimal decay estimates of weak solutions in L2 norm are derived under the different conditions on the initial velocity. Moreover, the error estimates of the difference between non-Newtonian flow and Navier-Stokes flow are also investigated.

  4. Investigation on the Core Bypass Flow in a Very High Temperature Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Hassan, Yassin

    2013-10-22

    Uncertainties associated with the core bypass flow are some of the key issues that directly influence the coolant mass flow distribution and magnitude, and thus the operational core temperature profiles, in the very high-temperature reactor (VHTR). Designers will attempt to configure the core geometry so the core cooling flow rate magnitude and distribution conform to the design values. The objective of this project is to study the bypass flow both experimentally and computationally. Researchers will develop experimental data using state-of-the-art particle image velocimetry in a small test facility. The team will attempt to obtain full field temperature distribution using racks of thermocouples. The experimental data are intended to benchmark computational fluid dynamics (CFD) codes by providing detailed information. These experimental data are urgently needed for validation of the CFD codes. The following are the project tasks: • Construct a small-scale bench-top experiment to resemble the bypass flow between the graphite blocks, varying parameters to address their impact on bypass flow. Wall roughness of the graphite block walls, spacing between the blocks, and temperature of the blocks are some of the parameters to be tested. • Perform CFD to evaluate pre- and post-test calculations and turbulence models, including sensitivity studies to achieve high accuracy. • Develop the state-of-the art large eddy simulation (LES) using appropriate subgrid modeling. • Develop models to be used in systems thermal hydraulics codes to account and estimate the bypass flows. These computer programs include, among others, RELAP3D, MELCOR, GAMMA, and GAS-NET. Actual core bypass flow rate may vary considerably from the design value. Although the uncertainty of the bypass flow rate is not known, some sources have stated that the bypass flow rates in the Fort St. Vrain reactor were between 8 and 25 percent of the total reactor mass flow rate. If bypass flow rates are on the

  5. Influence of biogas flow rate on biomass composition during the optimization of biogas upgrading in microalgal-bacterial processes.

    Science.gov (United States)

    Serejo, Mayara L; Posadas, Esther; Boncz, Marc A; Blanco, Saúl; García-Encina, Pedro; Muñoz, Raúl

    2015-03-03

    The influence of biogas flow rate (0, 0.3, 0.6, and 1.2 m(3) m(-2) h(-1)) on the elemental and macromolecular composition of the algal-bacterial biomass produced from biogas upgrading in a 180 L photobioreactor interconnected to a 2.5 L external bubbled absorption column was investigated using diluted anaerobically digested vinasse as cultivation medium. The influence of the external liquid recirculation/biogas ratio (0.5 biogas, was also evaluated. A L/G ratio of 10 was considered optimum to support CO2 and H2S removals of 80% and 100%, respectively, at all biogas flow rates tested. Biomass productivity increased at increasing biogas flow rate, with a maximum of 12 ± 1 g m(-2) d(-1) at 1.2 m(3) m(-2) h(-1), while the C, N, and P biomass content remained constant at 49 ± 2%, 9 ± 0%, and 1 ± 0%, respectively, over the 175 days of experimentation. The high carbohydrate contents (60-76%), inversely correlated to biogas flow rates, would allow the production of ≈100 L of ethanol per 1000 m(3) of biogas upgraded under a biorefinery process approach.

  6. Convective high-speed flow and field-aligned high-speed flows explored by TC-1

    Institute of Scientific and Technical Information of China (English)

    ZHANG LingQian; LIU ZhenXing; MA ZhiWei; W.BAUMJOHANN; M.W.DUNLOP4; WANG GuangJun; WANG Xiao; H.REME; C.CARR

    2008-01-01

    From June 1, 2004 to October 31, 2006, a total 465 high-speed flow events are observed by the TC-1 satellite in the near-Earth region (-13 RE < X < -9 RE, |Y|<10 RE, |2|<5 RE). Based on the angle between the flow and the magnetic field, the high-speed flow events are further divided into two types, that is,field-aligned high-speed flow (FAHF) in the plasma sheet boundary and convective bursty bulk flow (BBF) in the center plasma sheet. Among the total 465 high-speed flow events, there are 371 FAHFs,and 94 BBFs. The CHF are mainly concentrated in the plasma sheet, the intersection angle between the flow and the magnetic field is larger, the magnetic field intensity is relatively weak. The FHF are mainly distributed near the boundary layer of the plasma sheet, the intersection angle between the flow and magnetic field is smaller, and the magnetic field intensity is relatively strong. The convective BBFs have an important effect on the substorm.

  7. Laminar flow at a three-dimensional stagnation point with large rates of injection

    Science.gov (United States)

    Libby, P. A.

    1976-01-01

    Exact calculations of the titled flow are presented and compared to the predictions of an asymptotic analysis for large rates of injection. The inner layer of the boundary layer is found to involve outflow in both orthogonal directions whether the external flow along the y axis is inward or outward. As a result, the flow at a nearly two-dimensional stagnation point involves drastic changes as a weak outflow changes to a weak inflow. It is also found that the velocity profiles in the two directions in the inner layer are quite different.

  8. Unsteady Unidirectional Flow of Voigt Fluid through the Parallel Microgap Plates with Wall Slip and Given Inlet Volume Flow Rate Variations

    OpenAIRE

    Yinwei Lin; Chen, C. K.

    2015-01-01

    In order to solve the velocity profile and pressure gradient of the unsteady unidirectional slip flow of Voigt fluid, Laplace transform method is adopted in this research. Between the parallel microgap plates, the flow motion is induced by a prescribed arbitrary inlet volume flow rate which varies with time. The velocity slip condition on the wall and the flow conditions are known. In this paper, two basic flow situations are solved, which are a suddenly started and a constant acc...

  9. Mass flow-rate control unit to calibrate hot-wire sensors

    Energy Technology Data Exchange (ETDEWEB)

    Durst, F.; Uensal, B. [FMP Technology GmbH, Erlangen (Germany); Haddad, K. [FMP Technology GmbH, Erlangen (Germany); Friedrich-Alexander-Universitaet Erlangen-Nuernberg, LSTM-Erlangen, Institute of Fluid Mechanics, Erlangen (Germany); Al-Salaymeh, A.; Eid, Shadi [University of Jordan, Mechanical Engineering Department, Faculty of Engineering and Technology, Amman (Jordan)

    2008-02-15

    Hot-wire anemometry is a measuring technique that is widely employed in fluid mechanics research to study the velocity fields of gas flows. It is general practice to calibrate hot-wire sensors against velocity. Calibrations are usually carried out under atmospheric pressure conditions and these suggest that the wire is sensitive to the instantaneous local volume flow rate. It is pointed out, however, that hot wires are sensitive to the instantaneous local mass flow rate and, of course, also to the gas heat conductivity. To calibrate hot wires with respect to mass flow rates per unit area, i.e., with respect to ({rho}U), requires special calibration test rigs. Such a device is described and its application is summarized within the ({rho}U) range 0.1-25 kg/m{sup 2} s. Calibrations are shown to yield the same hot-wire response curves for density variations in the range 1-7 kg/m{sup 3}. The application of the calibrated wires to measure pulsating mass flows is demonstrated, and suggestions are made for carrying out extensive calibrations to yield the ({rho}U) wire response as a basis for advanced fluid mechanics research on ({rho}U) data in density-varying flows. (orig.)

  10. Computational analysis of high-throughput flow cytometry data

    Science.gov (United States)

    Robinson, J Paul; Rajwa, Bartek; Patsekin, Valery; Davisson, Vincent Jo

    2015-01-01

    Introduction Flow cytometry has been around for over 40 years, but only recently has the opportunity arisen to move into the high-throughput domain. The technology is now available and is highly competitive with imaging tools under the right conditions. Flow cytometry has, however, been a technology that has focused on its unique ability to study single cells and appropriate analytical tools are readily available to handle this traditional role of the technology. Areas covered Expansion of flow cytometry to a high-throughput (HT) and high-content technology requires both advances in hardware and analytical tools. The historical perspective of flow cytometry operation as well as how the field has changed and what the key changes have been discussed. The authors provide a background and compelling arguments for moving toward HT flow, where there are many innovative opportunities. With alternative approaches now available for flow cytometry, there will be a considerable number of new applications. These opportunities show strong capability for drug screening and functional studies with cells in suspension. Expert opinion There is no doubt that HT flow is a rich technology awaiting acceptance by the pharmaceutical community. It can provide a powerful phenotypic analytical toolset that has the capacity to change many current approaches to HT screening. The previous restrictions on the technology, based on its reduced capacity for sample throughput, are no longer a major issue. Overcoming this barrier has transformed a mature technology into one that can focus on systems biology questions not previously considered possible. PMID:22708834

  11. Debris-flow deposits and watershed erosion rates near southern Death Valley, CA, United States

    Science.gov (United States)

    Schmidt, K.M.; Menges, C.M.; ,

    2003-01-01

    Debris flows from the steep, granitic hillslopes of the Kingston Range, CA are commensurate in age with nearby fluvial deposits. Quaternary chronostratigraphic differentiation of debris-flow deposits is based upon time-dependent characteristics such as relative boulder strength, derived from Schmidt Hammer measurements, degree of surface desert varnish, pedogenesis, and vertical separation. Rock strength is highest for Holocene-aged boulders and decreases for Pleistocene-aged boulders weathering to grus. Volumes of age-stratified debris-flow deposits, constrained by deposit thickness above bedrock, GPS surveys, and geologic mapping, are greatest for Pleistocene deposits. Shallow landslide susceptibility, derived from a topographically based GIS model, in conjunction with deposit volumes produces watershed-scale erosion rates of ???2-47 mm ka-1, with time-averaged Holocene rates exceeding Pleistocene rates. ?? 2003 Millpress.

  12. Flow rate and humidification effects on a PEM fuel cell performance and operation

    Science.gov (United States)

    Guvelioglu, Galip H.; Stenger, Harvey G.

    A new algorithm is presented to integrate component balances along polymer electrolyte membrane fuel cell (PEMFC) channels to obtain three-dimensional results from a detailed two-dimensional finite element model. The analysis studies the cell performance at various hydrogen flow rates, air flow rates and humidification levels. This analysis shows that hydrogen and air flow rates and their relative humidity are critical to current density, membrane dry-out, and electrode flooding. Uniform current densities along the channels are known to be critical for thermal management and fuel cell life. This approach, of integrating a detailed two-dimensional across-the-channel model, is a promising method for fuel cell design due to its low computational cost compared to three-dimensional computational fluid dynamics models, its applicability to a wide range of fuel cell designs, and its ease of extending to fuel cell stack models.

  13. Pre-Spud Mud Loss Flow Rate in Steeply Folded Structures

    Directory of Open Access Journals (Sweden)

    Wang Zhiyuan

    2014-12-01

    Full Text Available In this paper, a new method that predicts the pre-spud mud loss flow rate in formations with tectonic fractures of steeply folded structures is proposed. The new method is based on finite element analysis of the palaeo-tectonic and current tectonic stress field and fracture distribution. The steps of the method are as follows. First, palaeo-tectonic stress distribution is simulated through finite element analysis. The tectonic fracture distribution of the region is obtained by combining rock failure criteria with palaeo-tectonic stress distribution. Afterward, the tectonic fracture density, aperture, porosity and permeability are calculated by studying the rebuilding process of current stress to the fracture parameters. Finally, the mud loss flow rate is calculated according to fracture parameters and the basic data of a given well. The new method enables the prediction of the mud loss flow rate before drilling steeply folded structures.

  14. Primary standards for measuring flow rates from 100 nl/min to 1 ml/min - gravimetric principle.

    Science.gov (United States)

    Bissig, Hugo; Petter, Harm Tido; Lucas, Peter; Batista, Elsa; Filipe, Eduarda; Almeida, Nelson; Ribeiro, Luis Filipe; Gala, João; Martins, Rui; Savanier, Benoit; Ogheard, Florestan; Niemann, Anders Koustrup; Lötters, Joost; Sparreboom, Wouter

    2015-08-01

    Microflow and nanoflow rate calibrations are important in several applications such as liquid chromatography, (scaled-down) process technology, and special health-care applications. However, traceability in the microflow and nanoflow range does not go below 16 μl/min in Europe. Furthermore, the European metrology organization EURAMET did not yet validate this traceability by means of an intercomparison between different National Metrology Institutes (NMIs). The NMIs METAS, Centre Technique des Industries Aérauliques et Thermiques, IPQ, Danish Technological Institute, and VSL have therefore developed and validated primary standards to cover the flow rate range from 0.1 μl/min to at least 1 ml/min. In this article, we describe the different designs and methods of the primary standards of the gravimetric principle and the results obtained at the intercomparison for the upper flow rate range for the various NMIs and Bronkhorst High-Tech, the manufacturer of the transfer standards used.

  15. Effect of transient change in strain rate on plastic flow behaviour of low carbon steel

    Indian Academy of Sciences (India)

    A Ray; P Barat; P Mukherjee; A Sarkar; S K Bandyopadhyay

    2007-02-01

    Plastic flow behaviour of low carbon steel has been studied at room temperature during tensile deformation by varying the initial strain rate of 3.3 × 10-4 s-1 to a final strain rate ranging from 1.33 × 10-3 s-1 to 2 × 10-3 s-1 at a fixed engineering strain of 12%. Haasen plot revealed that the mobile dislocation density remained almost invariant at the juncture where there was a sudden increase in stress with a change in strain rate and the plastic flow was solely dependent on the velocity of mobile dislocations. In that critical regime, the variation of stress with time was fitted with a Boltzmann type Sigmoid function. The increase in stress was found to increase with final strain rate and the time elapsed in attaining these stress values showed a decreasing trend. Both of these parameters saturated asymptotically at a higher final strain rate.

  16. Numerical simulations of high Knudsen number gas flows and microchannel electrokinetic liquid flows

    Science.gov (United States)

    Yan, Fang

    Low pressure and microchannel gas flows are characterized by high Knudsen numbers. Liquid flows in microchannels are characterized by non-conventional driving potentials like electrokinetic forces. The main thrust of the dissertation is to investigate these two different kinds of flows in gases and liquids respectively. High Knudsen number (Kn) gas flows were characterized by 'rarified' or 'microscale' behavior. Because of significant non-continuum effect, traditional CFD techniques are often inaccurate for analyzing high Kn number gas flows. The direct simulation Monte Carlo (DSMC) method offers an alternative to traditional CFD which retains its validity in slip and transition flow regimes. To validate the DSMC code, comparisons of simulation results with theoretical analysis and experimental data are made. The DSMC method was first applied to compute low pressure, high Kn flow fields in partially heated two dimensional channels. The effects of varying pressure, inlet flow and gas transport properties (Kn, Reynolds number, Re and the Prandtl number, Pr respectively) on the wall heat transfer (Nusselt number, Nu) were examined. The DSMC method was employed to explore mixing gas flows in two dimensional microchannels. Mixing of two gas streams (H2 and O2) was considered within a microchannel. The effect of the inlet-outlet pressure difference, the pressure ratio of the incoming streams and the accommodation coefficient of the solid wall on mixing length were all examined. Parallelization of a three-dimensional DSMC code was implemented using OpenMP procedure on a shared memory multi-processor computer. The parallel code was used to simulate 3D high Kn number Couette flow and the flow characteristics are found to be very different from their continuum counterparts. A mathematical model describing electrokinetically driven mass transport phenomena in microfabricated chip devices will also be presented. The model accounts for the principal physical phenomena affecting

  17. Estimation of Leak Flow Rate during Post-LOCA Using Cascaded Fuzzy Neural Networks

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Yeong [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Na, Man Gyun [Chosun University, Gwangju (Korea, Republic of)

    2016-10-15

    In this study, important parameters such as the break position, size, and leak flow rate of loss of coolant accidents (LOCAs), provide operators with essential information for recovering the cooling capability of the nuclear reactor core, for preventing the reactor core from melting down, and for managing severe accidents effectively. Leak flow rate should consist of break size, differential pressure, temperature, and so on (where differential pressure means difference between internal and external reactor vessel pressure). The leak flow rate is strongly dependent on the break size and the differential pressure, but the break size is not measured and the integrity of pressure sensors is not assured in severe circumstances. In this paper, a cascaded fuzzy neural network (CFNN) model is appropriately proposed to estimate the leak flow rate out of break, which has a direct impact on the important times (time approaching the core exit temperature that exceeds 1200 .deg. F, core uncover time, reactor vessel failure time, etc.). The CFNN is a data-based model, it requires data to develop and verify itself. Because few actual severe accident data exist, it is essential to obtain the data required in the proposed model using numerical simulations. In this study, a CFNN model was developed to predict the leak flow rate before proceeding to severe LOCAs. The simulations showed that the developed CFNN model accurately predicted the leak flow rate with less error than 0.5%. The CFNN model is much better than FNN model under the same conditions, such as the same fuzzy rules. At the result of comparison, the RMS errors of the CFNN model were reduced by approximately 82 ~ 97% of those of the FNN model.

  18. Co-Relationships between Glandular Salivary Flow Rates and Dental Caries

    Science.gov (United States)

    de Guillory, Carolina Diaz; Schoolfield, John D; Johnson, Dorthea; Yeh, Chih-Ko; Chen, Shuo; Cappelli, David P; Bober-Moken, Irene G; Dang, Howard

    2013-01-01

    Objective This study was designed to evaluate the relationship of age, gender, ethnicity and salivary flow rates on dental caries in an adult population using data collected from the Oral Health San Antonio Longitudinal Study of Aging (OH:SALSA). Background Saliva is essential to maintain a healthy oral environment and diminished output can result in dental caries. Although gender and age play a role in the quantity of saliva, little is known about the interaction of age, gender and ethnicity on dental caries and salivary flow rates. Materials and Methods Data from the 1,147 participants in the OH: SALSA was analyzed. The dependent variables were the number of teeth with untreated coronal caries, number of teeth with root caries, and the number of coronal and root surfaces with untreated caries. The independent variables were stimulated and unstimulated glandular salivary flow rates along with the age, sex, and ethnicity (e.g. European or Mexican ancestry) of the participants. Results Coronal caries experience was greater in younger participants while root surface caries experience was greater in the older participants. Coronal caries was lower in the older age groups while the root caries experience increased. Men had a statistically significant (p<0.02) higher experience of root caries than women. Values for unstimulated and stimulated parotid salivary flow rates showed no age difference and remained constant with age, whereas the age differences in the unstimulated and stimulated submandibular/sublingual salivary flow rates were significant. The mean number of teeth with coronal and root caries was higher in Mexican-Americans than in European-Americans. Conclusions Over one-fourth of the adults between the ages of 60 and 79 have untreated root caries over one-third having untreated coronal caries. Lower salivary flow rates play a significant role in the both the number of teeth and the number of surfaces developing caries in these adults. Women and individuals

  19. Strain rate effect in high-speed wire drawing process

    Science.gov (United States)

    He, S.; Van Houtte, P.; Van Bael, A.; Mei, F.; Sarban, A.; Boesman, P.; Galvez, F.; Atienza, J. M.

    2002-05-01

    This paper presents a study on the strain rate effect during high-speed wire drawing process by means of finite element simulation. Based on the quasistatic stresses obtained by normal tensile tests and dynamic stresses at high strain rates by split Hopkinson pressure bar tests, the wire drawing process was simulated for low carbon steel and high carbon steel. The results show that both the deformation process and the final properties of drawn wires are influenced by the strain rate.

  20. High-Rate Strong-Signal Quantum Cryptography

    Science.gov (United States)

    Yuen, Horace P.

    1996-01-01

    Several quantum cryptosystems utilizing different kinds of nonclassical lights, which can accommodate high intensity fields and high data rate, are described. However, they are all sensitive to loss and both the high rate and the strong-signal character rapidly disappear. A squeezed light homodyne detection scheme is proposed which, with present-day technology, leads to more than two orders of magnitude data rate improvement over other current experimental systems for moderate loss.

  1. Experimental characterization of breakage rate of colloidal aggregates in axisymmetric extensional flow.

    Science.gov (United States)

    Saha, Debashish; Soos, Miroslav; Lüthi, Beat; Holzner, Markus; Liberzon, Alex; Babler, Matthaus U; Kinzelbach, Wolfgang

    2014-12-09

    Aggregates prepared under fully destabilized conditions by the action of Brownian motion were exposed to an extensional flow generated at the entrance of a sudden contraction. Two noninvasive techniques were used to monitor their breakup process [i.e. light scattering and three-dimensional (3D) particle tracking velocimetry (3D-PTV)]. While the first one can be used to measure the size and the morphology of formed fragments after the breakage event, the latter is capable of resolving trajectories of individual aggregates up to the breakage point as well as the trajectories of formed fragments. Furthermore, measured velocity gradients were used to determine the local hydrodynamic conditions at the breakage point. All this information was combined to experimentally determine for the first time the breakage rate of individual aggregates, given in the form of a size reduction rate K(R), as a function of the applied strain rate, as well as the properties of the formed fragments (i.e., the number of formed fragments and the size ratio between the largest fragment and the original aggregate). It was found that K(R) scales with the applied strain rate according to a power law with the slope being dependent on the initial fractal dimension only, while the obtained data indicates a linear dependency of K(R) with the initial aggregate size. Furthermore, the probability distribution function (PDF) of the number of formed fragments and the PDF of the size ratio between the largest fragment and the original aggregate indicate that breakage will result with high probability (75%) in the formation of two to three fragments with a rather asymmetric ratio of sizes of about 0.8. The obtained results are well in agreement with the results from the numerical simulations published in the literature.

  2. Depressurization and two-phase flow of water containing high levels of dissolved nitrogen gas

    Science.gov (United States)

    Simoneau, R. J.

    1981-01-01

    Depressurization of water containing various concentrations of dissolved nitrogen gas was studied. In a nonflow depressurization experiment, water with very high nitrogen content was depressurized at rates from 0.09 to 0.50 MPa per second and a metastable behavior which was a strong function of the depressurization rate was observed. Flow experiments were performed in an axisymmetric, converging diverging nozzle, a two dimensional, converging nozzle with glass sidewalls, and a sharp edge orifice. The converging diverging nozzle exhibited choked flow behavior even at nitrogen concentration levels as low as 4 percent of the saturation level. The flow rates were independent of concentration level. Flow in the two dimensional, converging, visual nozzle appeared to have a sufficient pressure drop at the throat to cause nitrogen to come out of solution, but choking occurred further downstream. The orifice flow motion pictures showed considerable oscillation downstream of the orifice and parallel to the flow. Nitrogen bubbles appeared in the flow at back pressures as high as 3.28 MPa, and the level at which bubbles were no longer visible was a function of nitrogen concentration.

  3. Investigations on efficiencies of HT solar collectors for different flow rates and collector tilts

    DEFF Research Database (Denmark)

    Chen, Ziqian; Perers, Bengt; Furbo, Simon;

    2013-01-01

    Two HT solar collectors for solar heating plants from Arcon Solvarme A/S are tested in a laboratory test facility for solar collectors at Technical University of Denmark (DTU). The collectors are designed in the same way. However, one solar collector is equipped with an ETFE foil between...... the absorber and the cover glass and the other is without ETFE foil. The efficiencies for the collectors are tested at different flow rates and tilt. On the basis of the measured efficiencies, the efficiencies for the collectors as functions of flow rates are obtained. The calculated efficiencies are in good...... agreement with the measured efficiencies....

  4. Cash flow and discount rate risk in up and down markets: What is actually priced?

    OpenAIRE

    Botshekan, M.; Kraeussl, R.G.W.; Lucas, A

    2010-01-01

    This discussion paper resulted in a publication in the 'Journal of Financial and Quantitative Analysis', 2012, 47(6), 1279-1301. We test whether asymmetric preferences for losses versus gains as in Ang, Chen, and Xing (2006) also affect the pricing of cash flow versus discount rate news as in Campbell and Vuolteenaho (2004). We construct a new four-fold beta decomposition, distinguishing cash flow and discount rate betas in up and down markets. Using CRSP data over 1963--2008, we find that th...

  5. Robust and Optimal Control of Magnetic Microparticles inside Fluidic Channels with Time-Varying Flow Rates

    Directory of Open Access Journals (Sweden)

    Islam S.M. Khalil

    2016-06-01

    Full Text Available Targeted therapy using magnetic microparticles and nanoparticles has the potential to mitigate the negative side-effects associated with conventional medical treatment. Major technological challenges still need to be addressed in order to translate these particles into in vivo applications. For example, magnetic particles need to be navigated controllably in vessels against flowing streams of body fluid. This paper describes the motion control of paramagnetic microparticles in the flowing streams of fluidic channels with time-varying flow rates (maximum flow is 35 ml.hr−1. This control is designed using a magnetic-based proportional-derivative (PD control system to compensate for the time-varying flow inside the channels (with width and depth of 2 mm and 1.5 mm, respectively. First, we achieve point-to-point motion control against and along flow rates of 4 ml.hr−1, 6 ml.hr−1, 17 ml.hr−1, and 35 ml.hr−1. The average speeds of single microparticle (with average diameter of 100 μm against flow rates of 6 ml.hr−1 and 30 ml.hr−1 are calculated to be 45 μm.s−1 and 15 μm.s−1, respectively. Second, we implement PD control with disturbance estimation and compensation. This control decreases the steady-state error by 50%, 70%, 73%, and 78% at flow rates of 4 ml.hr−1, 6 ml.hr−1, 17 ml.hr−1, and 35 ml.hr−1, respectively. Finally, we consider the problem of finding the optimal path (minimal kinetic energy between two points using calculus of variation, against the mentioned flow rates. Not only do we find that an optimal path between two collinear points with the direction of maximum flow (middle of the fluidic channel decreases the rise time of the microparticles, but we also decrease the input current that is supplied to the electromagnetic coils by minimizing the kinetic energy of the microparticles, compared to a PD control with disturbance compensation.

  6. Robust and Optimal Control of Magnetic Microparticles Inside Fluidic Channels with Time-varying Flow Rates

    Directory of Open Access Journals (Sweden)

    Islam S.M. Khalil

    2016-06-01

    Full Text Available Targeted therapy using magnetic microparticles and nanoparticles has the potential to mitigate the negative side-effects associated with conventional medical treatment. Major technological challenges still need to be addressed in order to translate these particles into in vivo applications. For example, magnetic particles need to be navigated controllably in vessels against flowing streams of body fluid. This paper describes the motion control of paramagnetic microparticles in the flowing streams of fluidic channels with time-varying flow rates (maximum flow is 35 ml.hr-1. This control is designed using a magnetic-based proportional-derivative (PD control system to compensate for the time-varying flow inside the channels (with width and depth of 2 mm and 1.5 mm, respectively. First, we achieve point-to-point motion control against and along flow rates of 4 ml.hr-1, 6 ml.hr-1, 17 ml.hr-1, and 35 ml.hr-1. The average speeds of single microparticle (with average diameter of 100 μm against flow rates of 6 ml.hr-1 and 30 ml.hr-1 are calculated to be 45 μm.s-1 and 15 μm.s-1, respectively. Second, we implement PD control with disturbance estimation and compensation. This control decreases the steady-state error by 50%, 70%, 73%, and 78% at flow rates of 4 ml.hr-1, 6 ml.hr-1, 17 ml.hr-1, and 35 ml.hr-1, respectively. Finally, we consider the problem of finding the optimal path (minimal kinetic energy between two points using calculus of variation, against the mentioned flow rates. Not only do we find that an optimal path between two collinear points with the direction of maximum flow (middle of the fluidic channel decreases the rise time of the microparticles, but we also decrease the input current that is supplied to the electromagnetic coils by minimizing the kinetic energy of the microparticles, compared to a PD control with disturbance compensation.

  7. Flow structure around high-speed train in open air

    Institute of Scientific and Technical Information of China (English)

    田红旗; 黄莎; 杨明智

    2015-01-01

    According to the analysis of the turbulent intensity level around the high-speed train, the maximum turbulent intensity ranges from 0.2 to 0.5 which belongs to high turbulent flow. The flow field distribution law was studied and eight types of flow regions were proposed. They are high pressure with air stagnant region, pressure decreasing with air accelerating region, low pressure with high air flow velocity region I, turbulent region, steady flow region, low pressure with high air flow velocity region II, pressure increasing with air decelerating region and wake region. The analysis of the vortex structure around the train shows that the vortex is mainly induced by structures with complex mutation and large curvature change. The head and rear of train, the underbody structure, the carriage connection section and the wake region are the main vortex generating sources while the train body with even cross-section has rare vortexes. The wake structure development law studied lays foundation for the train drag reduction.

  8. Instrument for thermal radiation flux measurement in high temperature gas flow (Cuernavaca instrument)

    Energy Technology Data Exchange (ETDEWEB)

    Afgan, N.H. [Universidade Tecnica, Lisbon (Portugal); Leontiev, A.I. [Moscow State Technical University (Russian Federation)

    1995-05-01

    A new instrument for hemispherical radiation heat flux measurement is proposed. It is based on the theory of blow of the boundary layer, taking into account that at the critical mass flow rate through the porous surface the thermal boundary layer is blown off and only radiation flux from high temperature gases reaches the porous surface. With the measurement of blow of gas flow and the temperature of the porous material, the respective heat flux is obtained. (author)

  9. Impact of bypass flow rate and catheter position in veno-venous extracorporeal membrane oxygenation on gas exchange in vivo.

    Science.gov (United States)

    Togo, Konomi; Takewa, Yoshiaki; Katagiri, Nobumasa; Fujii, Yutaka; Kishimoto, Satoru; Date, Kazuma; Miyamoto, Yuji; Tatsumi, Eisuke

    2015-06-01

    The clinical use of veno-venous extracorporeal membrane oxygenation (VVECMO) in adult patients with respiratory failure is rapidly increasing. However, recirculation of blood oxygenated by ECMO back into the circuit may occur in VVECMO, resulting in insufficient oxygenation. The cannula position and bypass flow rate are two major factors influencing recirculation, but the relationship and ideal configuration of these factors are not fully understood. In the present study, we attempted to clarify these parameters for effective gas exchange. VVECMO was performed in eight adult goats under general anesthesia. The position of the drainage cannula was fixed in the inferior vena cava (IVC), but the return cannula position was varied between the IVC, right atrium (RA), and superior vena cava (SVC). At each position, the recirculation rates calculated, and the adequacy of oxygen delivery by ECMO in supplying systemic oxygen demand was assessed by measuring the arterial oxygen saturation (SaO2) and pressure (PaO2). Although the recirculation rates increased as the bypass flow rates increased, SaO2 and PaO2 also increased in any position of return cannula. The recirculation rates and PaO2 were 27 ± 2% and 162 ± 16 mmHg, 36 ± 6% and 139 ± 11 mmHg, and 63 ± 6% and 77 ± 9 mmHg in the SVC, RA and IVC position at 4 L/min respectively. In conclusion, the best return cannula position was the SVC, and a high bypass flow rate was advantageous for effective oxygenation. Both the bypass flow rates and cannula position must be considered to achieve effective oxygenation.

  10. An investigation of the effect of pore scale flow on average geochemical reaction rates using direct numerical simulation

    Energy Technology Data Exchange (ETDEWEB)

    Molins, Sergi [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Division; Trebotich, David [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Computational Research Division; Steefel, Carl I. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Division; Shen, Chaopeng [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Computational Research Division

    2012-03-30

    The scale-dependence of geochemical reaction rates hinders their use in continuum scale models intended for the interpretation and prediction of chemical fate and transport in subsurface environments such as those considered for geologic sequestration of CO2. Processes that take place at the pore scale, especially those involving mass transport limitations to reactive surfaces, may contribute to the discrepancy commonly observed between laboratory-determined and continuum-scale or field rates. In this study we investigate the dependence of mineral dissolution rates on the pore structure of the porous media by means of pore scale modeling of flow and multicomponent reactive transport. The pore scale model is composed of high-performance simulation tools and algorithms for incompressible flow and conservative transport combined with a general-purpose multicomponent geochemical reaction code. The model performs direct numerical simulation of reactive transport based on an operator-splitting approach to coupling transport and reactions. The approach is validated with a Poiseuille flow single-pore experiment and verified with an equivalent 1-D continuum-scale model of a capillary tube packed with calcite spheres. Using the case of calcite dissolution as an example, the high-resolution model is used to demonstrate that nonuniformity in the flow field at the pore scale has the effect of decreasing the overall reactivity of the system, even when systems with identical reactive surface area are considered. In conclusion, the effect becomes more pronounced as the heterogeneity of the reactive grain packing increases, particularly where the flow slows sufficiently such that the solution approaches equilibrium locally and the average rate becomes transport-limited.

  11. High-efficiency design of a mixed-flow pump

    Institute of Scientific and Technical Information of China (English)

    KIM; Jin-Hyuk; AHN; Hyung-Jin; KIM; Kwang-Yong

    2010-01-01

    High-efficiency design of a mixed-flow pump has been carried out based on numerical analysis of a three-dimensional viscous flow.For analysis,the Reynolds-averaged Navier-Stokes equations with a shear stress transport turbulence model were discretized by finite-volume approximations.Structured grid system was constructed in the computational domain,which has O-type grids near the blade surfaces and H/J-type grids in other regions.The numerical results were validated with experimental data for the heads and hydraulic efficiencies at different flow coefficients.The hydraulic efficiency at the design flow coefficient was evaluated with variation of the geometric variables,i.e.,the area of the discharge and length of the vane in the diffuser.The result has shown that the hydraulic efficiency of a mixed-flow pump at the design condition is improved by the modification of the geometry.

  12. Deployable Emergency Shutoff Device Blocks High-Velocity Fluid Flows

    Science.gov (United States)

    Nabors, Sammy A.

    2015-01-01

    NASA's Marshall Space Flight Center has developed a device and method for blocking the flow of fluid from an open pipe. Motivated by the sea-bed oil-drilling catastrophe in the Gulf of Mexico in 2010, NASA innovators designed the device to plug, control, and meter the flow of gases and liquids. Anchored with friction fittings, spikes, or explosively activated fasteners, the device is well-suited for harsh environments and high fluid velocities and pressures. With the addition of instrumentation, it can also be used as a variable area flow metering valve that can be set based upon flow conditions. With robotic additions, this patent-pending innovation can be configured to crawl into a pipe then anchor and activate itself to block or control fluid flow.

  13. High Blood Pressure Rates Have Doubled Worldwide Since 1975

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_162069.html High Blood Pressure Rates Have Doubled Worldwide Since 1975 Most of ... News) -- The number of people worldwide with high blood pressure has nearly doubled over the past 40 years, ...

  14. Turbulent behaviour of non-cohesive sediment gravity flows at unexpectedly high flow density

    Science.gov (United States)

    Baker, Megan; Baas, Jaco H.; Malarkey, Jonathan; Kane, Ian

    2016-04-01

    Experimental lock exchange-type turbidity currents laden with non-cohesive silica-flour were found to be highly dynamic at remarkably high suspended sediment concentrations. These experiments were conducted to produce sediment gravity flows of volumetric concentrations ranging from 1% to 52%, to study how changes in suspended sediment concentration affects the head velocities and run-out distances of these flows, in natural seawater. Increasing the volumetric concentration of suspended silica-flour, C, up to C = 46%, within the flows led to a progressive increase in the maximum head velocity. This relationship suggests that suspended sediment concentration intensifies the density difference between the turbulent suspension and the ambient water, which drives the flow, even if almost half of the available space is occupied by sediment particles. However, from C = 46% to C = 52% a rapid reduction in the maximum head velocity was measured. It is inferred that at C = 46%, friction from grain-to-grain interactions begins to attenuate turbulence within the flows. At C > 46%, the frictional stresses become progressively more dominant over the turbulent forces and excess density, thus producing lower maximum head velocities. This grain interaction process started to rapidly reduce the run-out distance of the silica-flour flows at equally high concentrations of C ≥ 47%. All flows with C 9%. Yet, the critical flow concentration at which turbulence modulation commenced for these silica-flour laden flows appeared to be much higher. We suggest that Bagnold's 9% criterion cannot be applied to flows that carry fine-grained sediment, because turbulent forces are more important than dispersive forces, and frictional forces start to affect the flows only at concentrations just below the cubic packing density of spheres of C = 52%. These experimental results also imply that natural flows may be able to transport vast volumes of non-cohesive sediment with relative ease, especially

  15. Electron-impact vibrational excitation rates in the flow field of aeroassisted orbital transfer vehicles

    Science.gov (United States)

    Lee, J.-H.

    1985-01-01

    This paper examines the vibrational excitation rate processes expected in the flow field of aeroassisted orbital transfer vehicles (AOTVs). An analysis of the multiple-quantum vibrational excitation processes by electron impact is made to predict the vibrational excitation cross sections, rate coefficients, and relaxation times which control vibrational temperature. The expression for the rate of electron-vibration energy transfer is derived by solving the system of master equations which account for the multiple-level transitions. The vibrational excitation coefficients, which are the prerequisite physical quantities in solving the obtained vibrational equation, are calculated based on the theoretically predicted cross sections. These cross sections are obtained from quantum mechanical calculations, based on the concept that vibrational excitation of molecules by electron impact occurs through formation of an intermediate negative ion state. Finally, the modified Landau-Teller-type rate equation, which is suitable for the numerical calculations for the AOTV flow fields, is suggested.

  16. Research on Gas-liquid Flow Rate Optimization in Foam Drilling

    Science.gov (United States)

    Gao, B. K.; Sun, D. G.; Jia, Z. G.; Huang, Z. Q.

    2010-03-01

    With the advantages of less gas consumption, higher carrying rocks ability, lower leakage and higher penetration rate, foam drilling is widely used today in petroleum industry. In the process of foam underbalanced drilling, the mixture of gas, liquid and cuttings flows upwards through the annular, so it is a typical gas-liquid-solid multi-phase flow. In order to protect the reservoir and avoid borehole wall collapsing during foam drilling, it is crucial to ensure that the bottom hole pressure is lower than the formation pressure and higher than the formation collapse pressure, and in the mean time, foam drilling fluid in the whole wellbore should be in the best foam quality stage in order to have sufficient capacity to carry cuttings. In this paper, main relations between bottom hole pressure and gas-liquid injecting rate are analyzed with the underbalanced multiphase flow models. And in order to obtain precise flow pattern and flow pressure, the whole well bore is spatial meshed and iterative method is used. So, a convenient safety window expressed by gas-liquid injecting rate is obtained instead of that by bottom hole pressure. Finally, a foam drilling example from a block in Yemen is presented; the drilling results show that this method is reliable and practical.

  17. Cerberus Fossae and Elysium Planitia Lavas, Mars: Source Vents, Flow Rates, Edifice Styles and Water Interactions

    Science.gov (United States)

    Sakimoto, S. E. H.; Gregg, T. K. P.

    2004-01-01

    The Cerberus Fossae and Elysium Planitia regions have been suggested as some of the youngest martian surfaces since the Viking mission, although there was doubt whether the origins were predominantly volcanic or fluvial. The Mars Global Surveyor and Mars Odyssey Missions have shown that the region is certainly young in terms of the topographic preservation and the youthful crater counts (e.g. in the tens to a few hundred million yrs.). Numerous authors have shown that fluvial and volcanic features share common flow paths and vent systems, and that there is evidence for some interaction between the lava flows and underlying volatiles as well as the use by lavas and water of the same vent system. Given the youthful age and possible water-volcanism interaction environment, we'd like constraints on water and volcanic flux rates and interactions. Here, we model ranges of volcanic flow rates where we can well-constrain them, and consider the modest flow rate results results in context with local eruption styles, and track vent locations, edifice volumes, and flow sources and data.

  18. Effects of Gas Flow Rate on the Discharge Characteristics of a DC Excited Plasma Jet

    Science.gov (United States)

    Li, Xuechen; Jia, Pengying; Di, Cong; Bao, Wenting; Zhang, Chunyan

    2015-09-01

    A direct current (DC) source excited plasma jet consisting of a hollow needle anode and a plate cathode has been developed to form a diffuse discharge plume in ambient air with flowing argon as the working gas. Using optical and electrical methods, the discharge characteristics are investigated for the diffuse plasma plume. Results indicate that the discharge has a pulse characteristic, under the excitation of a DC voltage. The discharge pulse corresponds to the propagation process of a plasma bullet travelling from the anode to the cathode. It is found that, with an increment of the gas flow rate, both the discharge plume length and the current peak value of the pulsed discharge decrease in the laminar flow mode, reach their minima at about 1.5 L/min, and then slightly increase in the turbulent mode. However, the frequency of the pulsed discharge increases in the laminar mode with increasing the argon flow rate until the argon flow rate equals to about 1.5 L/min, and then slightly decreases in the turbulent mode. supported by National Natural Science Foundation of China (Nos. 10805013, 11375051), Funds for Distinguished Young Scientists of Hebei Province, China (No. A2012201045), Department of Education for Outstanding Youth Project of China (No. Y2011120), and Youth Project of Hebei University of China (No. 2011Q14)

  19. Performance of PEM fuel cells stack as affected by number of cell and gas flow-rate

    Science.gov (United States)

    Syampurwadi, A.; Onggo, H.; Indriyati; Yudianti, R.

    2017-03-01

    The proton exchange membrane fuel cell (PEMFC) is a promising technology as an alternative green energy due to its high power density, low operating temperatures, low local emissions, quiet operation and fast start up-shutdown. In order to apply fuel cell as portable power supply, the performance investigation of small number of cells is needed. In this study, PEMFC stacks consisting of 1, 3, 5 and 7-cells with an active area of 25 cm2 per cell have been designed and developed. Their was evaluated in variation of gas flow rate. The membrane electrode assembly (MEA) was prepared by hot-pressing commercial gas diffusion electrodes (Pt loading 0.5 mg/cm2) on pre-treated Nafion 117 membrane. The stacks were constructed using bipolar plates in serpentine pattern and Z-type gas flow configuration. The experimental results were presented as polarization and power output curves which show the effects of varying number of cells and H2/O2 flow-rates on the PEMFC performance. The experimental results showed that not only number of cells and gas flow-rates affected the fuel cells performance, but also the operating temperature as a result of electrochemistry reaction inside the cell.

  20. Review of flow rate estimates of the Deepwater Horizon oil spill

    Science.gov (United States)

    McNutt, Marcia K.; Camilli, Rich; Crone, Timothy J.; Guthrie, George D.; Hsieh, Paul A.; Ryerson, Thomas B.; Savas, Omer; Shaffer, Frank

    2012-01-01

    The unprecedented nature of the Deepwater Horizon oil spill required the application of research methods to estimate the rate at which oil was escaping from the well in the deep sea, its disposition after it entered the ocean, and total reservoir depletion. Here, we review what advances were made in scientific understanding of quantification of flow rates during deep sea oil well blowouts. We assess the degree to which a consensus was reached on the flow rate of the well by comparing in situ observations of the leaking well with a time-dependent flow rate model derived from pressure readings taken after the Macondo well was shut in for the well integrity test. Model simulations also proved valuable for predicting the effect of partial deployment of the blowout preventer rams on flow rate. Taken together, the scientific analyses support flow rates in the range of ~50,000–70,000 barrels/d, perhaps modestly decreasing over the duration of the oil spill, for a total release of ~5.0 million barrels of oil, not accounting for BP's collection effort. By quantifying the amount of oil at different locations (wellhead, ocean surface, and atmosphere), we conclude that just over 2 million barrels of oil (after accounting for containment) and all of the released methane remained in the deep sea. By better understanding the fate of the hydrocarbons, the total discharge can be partitioned into separate components that pose threats to deep sea vs. coastal ecosystems, allowing responders in future events to scale their actions accordingly.