WorldWideScience

Sample records for bi-directional continuous flow

  1. Development of an Advanced Flow Meter using the Averaging Bi-directional Flow Tube

    International Nuclear Information System (INIS)

    Advanced flow meter using the concept of averaging bi-directional flow tube was developed. To find characteristics of flow meter and derive theory of measurement in the single and two phase flow condition, some basic tests were attempted using flow meters with diameters of 27, 80 and 200 mm. The CFD(computational fluid dynamics) calculation was also performed to find the effects of temperature and pressure, and to optimize design of a prototypic flow meter. Following this procedure, prototypical flow meters with diameters of 200 and 500 mm were designed and manufactured. It is aimed to use in the region in which calibration constant was unchanged. The stress analysis showed that the proposed flow meter of H-beam shape is inherently strong against the bending force induced by flow. The flow computer was developed for the flow rate calculation from the measured pressure difference. In this study, the performance test using this prototype flow meter was carried out. The developed flow meter can be applied in the wide range of pressure and temperature. The basic tests showed that the lineality of the proposed flow meter is ± 0.5 % of full scale and flow turn down ratio is 1:20 where the Reynolds number is larger than 10,000

  2. Impact of holding umbrella on uni- and bi-directional pedestrian flow: Experiments and modeling

    CERN Document Server

    Guo, Ning; Jiang, Rui; Hu, Mao-Bin; Jia, Bin

    2016-01-01

    In this paper, the impact of holding umbrella on the uni- and bi-directional flow has been investigated via experiment and modeling. In the experiments, pedestrians are required to walk clockwise/anti-clockwise in a ring-shaped corridor under normal situation and holding umbrella situation. No matter in uni- or bi-directional flow, the flow rate under holding umbrella situation decreases comparing with that in normal situation. In bidirectional flow, pedestrians segregate into two opposite moving streams very quickly under normal situation, and clockwise/anti-clockwise walking pedestrians are always in the inner/outer lane due to right-walking preference. Under holding umbrella situation, spontaneous lane formation has also occurred. However, when holding umbrella, pedestrians may separate into more than two lanes. Moreover, the merge of lanes have been observed, and clockwise/anti-clockwise pedestrians are not always in the inner/outer lane. To model the flow dynamics, an improved force-based model has been ...

  3. Longitudinal force measurement in continuous welded rail with bi-directional FBG strain sensors

    Science.gov (United States)

    Wang, Ping; Xie, Kaize; Shao, Liyang; Yan, Lianshan; Xu, Jingmang; Chen, Rong

    2016-01-01

    In this work, a new method has been proposed to accurately determine longitudinal force measurement in continuous welded rail (CWR) with bi-directional fiber Bragg grating (B-FBGs) strain sensors (vertically and longitudinally installed according to the axis of rail). The response of B-FBGs has been theoretically analyzed by binding on CWR under different restrained conditions, where the coefficient of strain sensitivity of FBG is calibrated by its temperature sensitivity. Then the proposed sensor structure has been installed at two elaborately selected points on the subgrade on a Chinese high-speed railway in field. The experiment lasts for about 23 h. During the experiment, the rail temperature varied by about 7.8 °C and the differentials of relative value of wavelength change of B-FBGs of two points were 1.7850 × 10-5 and 1.4969 × 10-5. The maximum difference between the experimental and theoretical results is 13.8 kN. The experimental results agree with the theoretical analysis very well. To guarantee the measurement accuracy of over 95%, the ratio of strain sensitivity coefficients of two FBG sensors of B-FBGs structure at one test point shall be within 0.78 ˜ 1.22.

  4. A new method for the measurement of two-phase mass flow rate using average bi-directional flow tube

    International Nuclear Information System (INIS)

    Average bi-directional flow tube was suggested to apply in the air/steam-water flow condition. Its working principle is similar with Pitot tube, however, it makes it possible to eliminate the cooling system which is normally needed to prevent from flashing in the pressure impulse line of pitot tube when it is used in the depressurization condition. The suggested flow tube was tested in the air-water vertical test section which has 80mm inner diameter and 10m length. The flow tube was installed at 120 of L/D from inlet of test section. In the test, the pressure drop across the average bi-directional flow tube, system pressure and average void fraction were measured on the measuring plane. In the test, fluid temperature and injected mass flow rates of air and water phases were also measured by a RTD and two coriolis flow meters, respectively. To calculate the phasic mass flow rates : from the measured differential pressure and void fraction, Chexal drift-flux correlation was used. In the test a new correlation of momentum exchange factor was suggested. The test result shows that the suggested instrumentation using the measured void fraction and Chexal drift-flux correlation can predict the mass flow rates within 10% error of measured data

  5. A mathematical model and computational framework for three-dimensional chondrocyte cell growth in a porous tissue scaffold placed inside a bi-directional flow perfusion bioreactor.

    Science.gov (United States)

    Shakhawath Hossain, Md; Bergstrom, D J; Chen, X B

    2015-12-01

    The in vitro chondrocyte cell culture for cartilage tissue regeneration in a perfusion bioreactor is a complex process. Mathematical modeling and computational simulation can provide important insights into the culture process, which would be helpful for selecting culture conditions to improve the quality of the developed tissue constructs. However, simulation of the cell culture process is a challenging task due to the complicated interaction between the cells and local fluid flow and nutrient transport inside the complex porous scaffolds. In this study, a mathematical model and computational framework has been developed to simulate the three-dimensional (3D) cell growth in a porous scaffold placed inside a bi-directional flow perfusion bioreactor. The model was developed by taking into account the two-way coupling between the cell growth and local flow field and associated glucose concentration, and then used to perform a resolved-scale simulation based on the lattice Boltzmann method (LBM). The simulation predicts the local shear stress, glucose concentration, and 3D cell growth inside the porous scaffold for a period of 30 days of cell culture. The predicted cell growth rate was in good overall agreement with the experimental results available in the literature. This study demonstrates that the bi-directional flow perfusion culture system can enhance the homogeneity of the cell growth inside the scaffold. The model and computational framework developed is capable of providing significant insight into the culture process, thus providing a powerful tool for the design and optimization of the cell culture process.

  6. Boundary layer flow of three-dimensional viscoelastic nanofluid past a bi-directional stretching sheet with Newtonian heating

    Directory of Open Access Journals (Sweden)

    M. Ramzan

    2015-05-01

    Full Text Available This paper deals with steady three dimensional boundary layer flow of an incompressible viscoelastic nanofluid flow in the presence of Newtonian heating. An appropriate transformation is employed to convert the highly non linear partial differential equations into ordinary differential equations. Homotopy Analysis method (HAM is used to find series solution of the obtained coupled highly non linear differential equations. The convergence of HAM solutions is discussed via h-curves. Graphical illustrations displaying the influence of emerging parameters on velocity, temperature and concentration profiles are given. It is observed that γ the conjugate parameter for Newtonian heating show increasing behavior on both temperature and concentration profiles. However, the temperature and concentration profiles are increasing and decreasing functions of Brownian motion parameter Nb respectively.

  7. Organocatalysis in continuous flow

    NARCIS (Netherlands)

    Berg, van den S.A.

    2016-01-01

    Continuous flow chemistry is an enabling technique in organic chemistry. Advantages include extremely fast mixing and heat transfer capabilities as well as rapid screening of reaction conditions. Combining continuous flow chemistry with solid-supported organocatalysis presents challenges that have b

  8. Asymmetric reactions in continuous flow

    Directory of Open Access Journals (Sweden)

    Xiao Yin Mak

    2009-04-01

    Full Text Available An overview of asymmetric synthesis in continuous flow and microreactors is presented in this review. Applications of homogeneous and heterogeneous asymmetric catalysis as well as biocatalysis in flow are discussed.

  9. Monolithic Continuous-Flow Bioreactors

    Science.gov (United States)

    Stephanopoulos, Gregory; Kornfield, Julia A.; Voecks, Gerald A.

    1993-01-01

    Monolithic ceramic matrices containing many small flow passages useful as continuous-flow bioreactors. Ceramic matrix containing passages made by extruding and firing suitable ceramic. Pores in matrix provide attachment medium for film of cells and allow free movement of solution. Material one not toxic to micro-organisms grown in reactor. In reactor, liquid nutrients flow over, and liquid reaction products flow from, cell culture immobilized in one set of channels while oxygen flows to, and gaseous reaction products flow from, culture in adjacent set of passages. Cells live on inner surfaces containing flowing nutrient and in pores of walls of passages. Ready access to nutrients and oxygen in channels. They generate continuous high yield characteristic of immobilized cells, without large expenditure of energy otherwise incurred if necessary to pump nutrient solution through dense biomass as in bioreactors of other types.

  10. Development of a simple extraction cell with bi-directional continuous flow coupled on-line to ICP-MS for assessment of elemental associations in solid samples

    DEFF Research Database (Denmark)

    Buanuam, Janya; Tiptanasup, Kasipa; Shiowatana, Juwadee;

    2006-01-01

    reagents as addressed in the BCR scheme, that is, 0.11 M CH3COOH, 0.1 NH2OH·HCl and 30% H2O2, even when a well recognized matrix-sensitive detector, such as ICP-MS, is used. As a result of the enhanced temporal resolution of the ongoing extraction, insights into the breaking down of phases...

  11. Silent and Efficient Supersonic Bi-Directional Flying Wing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose a Phase I study for a novel concept of a supersonic bi-directional (SBiDir) flying wing (FW) that has the potential to revolutionize supersonic flight...

  12. Design of Bi-Directional Hydrofoils for Tidal Current Turbines

    Science.gov (United States)

    Nedyalkov, Ivaylo; Wosnik, Martin

    2015-11-01

    Tidal Current Turbines operate in flows which reverse direction. Bi-directional hydrofoils have rotational symmetry and allow such turbines to operate without the need for pitch or yaw control, decreasing the initial and maintenance costs. A numerical test-bed was developed to automate the simulations of hydrofoils in OpenFOAM and was utilized to simulate the flow over eleven classes of hydrofoils comprising a total of 700 foil shapes at different angles of attack. For promising candidate foil shapes physical models of 75 mm chord and 150 mm span were fabricated and tested in the University of New Hampshire High-Speed Cavitation Tunnel (HiCaT). The experimental results were compared to the simulations for model validation. The numerical test-bed successfully generated simulations for a wide range of foil shapes, although, as expected, the k - ω - SST turbulence model employed here was not adequate for some of the foils and for large angles of attack at which separation occurred. An optimization algorithm is currently being coupled with the numerical test-bed and additional turbulence models will be implemented in the future.

  13. Piezoelectric power converter with bi-directional power transfer

    OpenAIRE

    Meyer, Kaspar Sinding; Rødgaard, Martin Schøler; Andersen, Michael A. E.; Andersen, Thomas

    2014-01-01

    The present invention relates to a bi-directional piezoelectric power converter com¬ prising a piezoelectric transformer. The piezoelectric transformer comprises an input electrode electrically coupled to a primary section of the piezoelectric transformer and an output electrode electrically coupled to an output section of the piezoelectric transformer to provide a transformer output signal. A bi-directional switching circuit is coupled between the output electrode and a DC or AC output volta...

  14. Comparison of laser-assisted damage in soft tissue using bi-directional and forward-firing optical fiber

    Science.gov (United States)

    Kim, Changhwan; Sohn, Ik-Bu; Park, Hoyong; Lee, Yong Joong; Lee, Ho

    2014-03-01

    Laser-assisted endoscopic surgery is made possible by employing optical devices such as fiber optics and hollow wave-guides. In some applications of laser-assisted endoscopic surgery, it is necessary to change the direction of the light emission. Our group reported a new fabrication method for bi-directional firing fibers. The conical surface of the fiber tip made the bi-directional emission of the laser light at the distal end of the fiber. In this study, we employed the bi-directional firing fiber for laser-assisted coagulation of soft tissue. The developed fiber and the normal forward-firing fiber are used for the endoscopic delivery system of a continuous IR laser into an in vitro porcine liver. The ablation and coagulation pattern were compared for two distinctive fiber systems. Regardless of the laser's parameters, the bi-directional firing fiber produced a cavity and coagulation zone with more or less a circular shape, while the forward fiber produced an elongated cavity and coagulation region. The bi-directional firing fiber produced wider and shorter coagulation and cavity zones compared to that of the forward-firing fiber. We expect the bi-directional firing fiber to be an excellent optical delivery system for endoscopic laser-hyperthermia when used against various tumors in the liver, breast and thyroid.

  15. Global evaluation of ammonia bi-directional exchange

    Directory of Open Access Journals (Sweden)

    L. Zhu

    2015-02-01

    Full Text Available Bi-directional air–surface exchange of ammonia (NH3 has been neglected in many air quality models. In this study, we implement the bi-directional exchange of NH3 in the GEOS-Chem global chemical transport model. We also introduce an updated diurnal variability scheme for NH3 livestock emissions and evaluate the recently developed MASAGE_NH3 bottom up inventory. While updated diurnal variability improves comparison of modeled-to-hourly in situ measurements in the Southeastern US, NH3 concentrations decrease throughout the globe, up to 17 ppb in India and Southeastern China, with corresponding decreases in aerosol nitrate by up to 7 μg m−3. The ammonium (NH4+ soil pool in the bi-directional exchange model largely extends the NH3 lifetime in the atmosphere. Including bi-directional exchange generally increases NH3 gross emissions (7.1% and surface concentrations (up to 3.9 ppb throughout the globe in July, except in India and Southeastern China. In April and October, it decreases NH3 gross emissions in the Northern Hemisphere (e.g., 43.6% in April in China and increases NH3 gross emissions in the Southern Hemisphere. Bi-directional exchange does not largely impact NH4+ wet deposition overall. While bi-directional exchange is fundamentally a better representation of NH3 emissions from fertilizers, emissions from primary sources are still underestimated and thus significant model biases remain when compared to in situ measurements in the US. The adjoint of bi-directional exchange has also been developed for the GEOS-Chem model and is used to investigate the sensitivity of NH3 concentrations with respect to soil pH and fertilizer application rate. This study thus lays the groundwork for future inverse modeling studies to more directly constrain these physical processes rather than tuning bulk uni-directional NH3 emissions.

  16. Piezoelectric power converter with bi-directional power transfer

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a bi-directional piezoelectric power converter com¬ prising a piezoelectric transformer. The piezoelectric transformer comprises an input electrode electrically coupled to a primary section of the piezoelectric transformer and an output electrode electrically...... coupled to an output section of the piezoelectric transformer to provide a transformer output signal. A bi-directional switching circuit is coupled between the output electrode and a DC or AC output voltage of the power converter. Forward and reverse current conducting periods of the bi......, a reverse current is conducted through the bi-directional switching circuit from the DC or AC output voltage to the output electrode to discharge the DC or AC output voltage and return power to the primary section of the piezoelectric transformer....

  17. Detailed string stability analysis for bi-directional optimal velocity model

    Institute of Scientific and Technical Information of China (English)

    郑亮

    2015-01-01

    The class of bi-directional optimal velocity models can describe the bi-directional looking effect that usually exists in the reality and is even enhanced with the development of the connected vehicle technologies. Its combined string stability condition can be obtained through the method of the ring-road based string stability analysis. However, the partial string stability about traffic fluctuation propagated backward or forward was neglected, which will be analyzed in detail in this work by the method of transfer function and its H∞norm from the viewpoint of control theory. Then, through comparing the conditions of combined and partial string stabilities, their relationships can make traffic flow be divided into three distinguishable regions, displaying various combined and partial string stability performance. Finally, the numerical experiments verify the theoretical results and find that the final displaying string stability or instability performance results from the accumulated and offset effects of traffic fluctuations propagated from different directions.

  18. Error analisis of passager flow based on the bi-directional flow ratio of the section in crowd gathering early-warning%人群聚集预警中基于断面双向流量比的客流误差分析

    Institute of Scientific and Technical Information of China (English)

    李焘; 金龙哲; 刘建

    2013-01-01

    An early warning method for the risk of crowd gathering based on the bi-directional flow ratio of the section was proposed according to the characteristics of the opposite movement of pedestrian flow at the business street. Its error was analyzed in theory and verified by an example. It is found that using this method as a criterion of crowded events is feasible. Whether the measured values are greater or less than the true values, the error of the ratio between the inward and the outward flow across the section is less than that from a pedestrian flow statistic system, so the method is helpful for improving the accuracy of crowd statistic tools to some extent. In addition, the method can be used as a reference in selecting the type of a pedestrian flow statistic system according to requirements for the measuring accuracy of actual applications.%针对密集人群的安全预警管理,结合商业街人流相向运动的特点,提出通过断面双向流量比进行人群聚集风险预警的思路,并对该方法的误差进行了理论分析和实例验证.结果表明该方法用于商业街聚集人群的风险预警时,不论测量值大于真实值还是测量值小于真实值,经过断面进出比的比值误差均比客流统计系统本身误差更小,从而使客流统计产品在一定范围内精确度有所提高.此外,可应用此方法根据实际要求的测量精度为客流统计设备选型提供依据.

  19. Continuous-Flow Centrifugal Separator

    Science.gov (United States)

    Waldron, Robert D.

    1988-01-01

    Apparatus combines principles of centrifugal and cyclone separators to control movement of solid or liquid particles suspended in flowing gas. Spinning disk contains radial channels, width varys as function of distance from center. Gas flows from outer ring around disk toward center. Particles in gas collected at periphery, center or both.

  20. Transfer of Pragmatic Competences: A Bi-Directional Perspective

    Science.gov (United States)

    Su, I-Ru

    2010-01-01

    This study investigated the bi-directionality of language transfer (first language [L1] to second language [L2] and L2 to L1) at the pragmatic level with a focus on the speech act of request. The L2 participants were Chinese English as a foreign language (EFL) learners at the intermediate and advanced levels. Data were collected via discourse…

  1. Bi-directional Secure Communication Based on Discrete Chaotic Synchronization

    Institute of Scientific and Technical Information of China (English)

    LONG Min; QIU Shui-Sheng; PENG Fei

    2007-01-01

    Discrete chaotic systems are used for bi-directional secure communication. Both sides of communication keep sending signals to achieve their synchronization, and then recover the messages. However, the third side without keys cannot get useful information. Known-plaintext attack is also engaged to analyze this method, and the simulation results show that the proposed method can reach high security performance.

  2. The bi-directional moving structures in a coronal bright point

    Science.gov (United States)

    Li, Dong; Ning, Zongjun; Su, Yingna

    2016-09-01

    We report the bi-directional moving structures in a coronal bright point (CBP) on 2015 July 14. It is observed by the Atmospheric Imaging Assembly (AIA) onboard Solar Dynamics Observatory (SDO). This CBP has a lifetime of ˜10 minutes, and a curved shape. The observations show that many bright structures are moving intermittently outward from the CBP brightness core. Such moving structures are clearly seen at AIA 171 Å, 193 Å, 211 Å, 131 Å, 94 Å, 335 Å and 304 Å, slit-jaw (SJI) 1330 Å and 1400 Å. In order to analyze these moving structures, the CBP is cut along the moving direction with a curved slit from the AIA and SJI images. Then we can obtain the time-distance slices, including the intensity and intensity-derivative diagrams, from which, the moving structures are recognized as the oblique streaks, and they are characterized by the bi-direction, simultaneity, symmetry, and periodicity. The average speed is around 300 km s^{-1}, while the typically period is ˜90 s. All these features (including the bi-directional flows and their periodicity) can be detected simultaneously at all the 9 wavelengths. This CBP takes place at the site between a small pair of magnetic polarities. High time resolution observations show that they are moving close to each other during its lifetime. These facts support the magnetic reconnection model of the CBP and the bi-directional moving structures could be the observational outflows after the reconnection. Therefore, they can be as the direct observation evidence of the magnetic reconnection.

  3. Bi-directional associations between psychological arousal, cortisol, and sleep

    DEFF Research Database (Denmark)

    Garde, Anne Helene; Albertsen, Karen; Persson, Roger;

    2012-01-01

    The aim was to elucidate the possible bi-directional relation between daytime psychological arousal, cortisol, and self-reported sleep in a group of healthy employees in active employment. Logbook ratings of sleep (Karolinska Sleep Questionnaire), stress, and energy, as well as positive and negat......The aim was to elucidate the possible bi-directional relation between daytime psychological arousal, cortisol, and self-reported sleep in a group of healthy employees in active employment. Logbook ratings of sleep (Karolinska Sleep Questionnaire), stress, and energy, as well as positive...... and problems during the day. The results underpin the possibility that arousal and poor sleep might create a self-reinforcing vicious circle that negatively affects a person's well-being....

  4. High Voltage Bi-directional Flyback Converter for Capacitive Actuator

    DEFF Research Database (Denmark)

    Thummala, Prasanth; Zhang, Zhe; Andersen, Michael A. E.

    2013-01-01

    This paper presents a high voltage DC-DC converter topology for bi-directional energy transfer between a low voltage DC source and a high voltage capacitive load. The topology is a bi-directional flyback converter with variable switching frequency control during the charge mode, and constant...... switching frequency control during the discharge mode. The converter is capable of charging the capacitive load from 24 V DC source to 2.5 kV, and discharges it to 0 V. The flyback converter has been analyzed in detail during both charge and discharge modes, by considering all the parasitic elements...... in the converter, including the most dominating parameters of the high voltage transformer viz., self-capacitance and leakage inductance. The specific capacitive load for this converter is a dielectric electro active polymer (DEAP) actuator, which can be used as an effective replacement for conventional actuators...

  5. Bi-directional normalized difference vegetation index: concept and application

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The data products of land surface bi-directional reflectance distribution function (BRDF) from the space-borne Polarization and Directionality of the Earth Reflectance (POLDER) of France and the Moderate Resolution Imaging Spectroradiometer (MODIS)of USA are available recently, but the atmospheric correction for meeting the requirement of quantitative remote sensing is still a very dfficult problem. This paper presents a concept: bi-directional normalized difference vegetation index (Bi-NDVI), in order to consider simul taneously the effects of both land surface BRDF and atmospheric path scattering. An atmospheric quality index is thus defined for satellite multi-angular observations. The quality of MODIS/BRDF data products can be improved notably through iterative inversion weighed by this index.

  6. Geologically controlled bi-directional exchange of groundwater with a hypersaline lake in the Canadian prairies

    Science.gov (United States)

    Bentley, Laurence R.; Hayashi, Masaki; Zimmerman, Elena P.; Holmden, Chris; Kelley, Lynn I.

    2016-06-01

    Hypersaline lakes occur in hydrologically closed basins due to evaporitic enrichment of dissolved salts transported to the lakes by surface water and groundwater. At the hypersaline Lydden Lake in Saskatchewan, Canada, groundwater/lake-water interaction is strongly influenced by the geological heterogeneity of glacial deposits, whereby a highly permeable glaciofluvial sand/gravel deposit is underlain by glaciolacustrine deposits consisting of dense clay interspersed with silt/sand lenses. Pressure head distribution in a near shore area indicates a bi-directional flow system. It consists of topographically driven flow of fresh groundwater towards the lake in the sand/gravel aquifer and density-driven, landward flow of saline groundwater in the underlying glaciolacustrine deposits. Electrical resistivity tomography, and chemical and isotopic composition of groundwater clearly show the landward intrusion of saline water in the heterogeneous unit. The feasibility of bi-directional flow and transport is supported by numerical simulations of density-coupled groundwater flow and transport. The results suggest that the geologically controlled groundwater exchange processes have substantial influences on both inputs and outputs of dissolved minerals in hypersaline lakes in closed basins.

  7. Hybrid battery with bi-directional DC/DC converter

    Directory of Open Access Journals (Sweden)

    DUDRIK Jaroslav

    2010-05-01

    Full Text Available Bi-directional buck-boost DC/DC converterfor hybrid battery is described in this paper. The firstpart of the paper is aimed at concept of hybrid battery;main advance compared to conventional accumulatoris explained there. Control circuit with UC3637 andpower circuit of the converter are described in thesecond part of the paper. Experimental results frommeasuring of converter are mentioned in the last part.

  8. Hybrid battery with bi-directional DC/DC converter

    OpenAIRE

    DUDRIK Jaroslav; OLEJAR Martin; BERES Tomáš

    2010-01-01

    Bi-directional buck-boost DC/DC converterfor hybrid battery is described in this paper. The firstpart of the paper is aimed at concept of hybrid battery;main advance compared to conventional accumulatoris explained there. Control circuit with UC3637 andpower circuit of the converter are described in thesecond part of the paper. Experimental results frommeasuring of converter are mentioned in the last part.

  9. High-Speed Optical Local Access Network System Using Bi-Directional Polarization Multiplexing

    Institute of Scientific and Technical Information of China (English)

    Mitsuru Miyauchi; Yanjun Sun

    2003-01-01

    A high-speed and economical optical local access network system is proposed where bi-directional polarization multiplexing is applied to a bi-directional transmission. Experimental results using a prototype system confirmlow optical loss and environmental stabilities.

  10. High-Speed Optical Local Access Network System Using Bi-Directional Polarization Multiplexing

    Institute of Scientific and Technical Information of China (English)

    Mitsuru; Miyauchi; Yanjun; Sun

    2003-01-01

    A high-speed and economical optical local access network system is proposed where bi-directional polarization multiplexing is applied to a bi-directional transmission. Experimental results using a prototype system confirm low optical loss and environmental stabilities.

  11. Continuous flow measurements using fixed ultrasonic meters

    Science.gov (United States)

    Oltmann, Rick

    1993-01-01

    USGS has or soon will be installing four continuous flow-monitoring stations in the delta that will use ultrasonic velocity meters (DVM). Funding for the stations has been provided by USGS, DWR, USBR, and Contra Costa Water District.

  12. Bi-Directional DC-DC Converter for PHEV Applications

    Energy Technology Data Exchange (ETDEWEB)

    Abas Goodarzi

    2011-01-31

    Plug-In Hybrid Electric Vehicles (PHEV) require high power density energy storage system (ESS) for hybrid operation and high energy density ESS for Electric Vehicle (EV) mode range. However, ESS technologies to maximize power density and energy density simultaneously are not commercially feasible. The use of bi-directional DC-DC converter allows use of multiple energy storage, and the flexible DC-link voltages can enhance the system efficiency and reduce component sizing. This will improve fuel consumption, increase the EV mode range, reduce the total weight, reduce battery initial and life cycle cost, and provide flexibility in system design.

  13. Catalytic Synthesis of Nitriles in Continuous Flow

    DEFF Research Database (Denmark)

    Nordvang, Emily Catherine

    The objective of this thesis is to report the development of a new, alternative process for the flexible production of nitrile compounds in continuous flow. Nitriles are an important class of compounds that find applications as solvents, chemical intermediates and pharmaceutical compounds......, alternative path to acetonitrile from ethanol via the oxidative dehydrogenation of ethylamine. The catalytic activity and product ratios of the batch and continuous flow reactions are compared and the effect of reaction conditions on the reaction is investigated. The effects of ammonia in the reaction...... dehydrogenation of ethylamine and post-reaction purging.Chapter 4 outlines the application of RuO2/Al2O3 catalysts to the oxidative dehydrogenation of benzylamine in air, utilizing a new reaction setup. Again, batch and continuous flow reactions are compared and the effects of reaction conditions, ammonia...

  14. Steady-state analysis of the integrated natural gas and electric power system with bi-directional energy conversion

    DEFF Research Database (Denmark)

    Zeng, Qing; Fang, Jiakun; Liu, Jinghua;

    2016-01-01

    Nowadays, the electric power system and natural gas network are becoming increasingly coupled and interdependent. A harmonized integration of natural gas and electricity network with bi-directional energy conversion is expected to accommodate high penetration levels of renewables in terms of system...... flexibility. This work focuses on the steady-state analysis of the integrated natural gas and electric power system with bi-directional energy conversion. A unified energy flow formulation is developed to describe the nodal balance and branch flow in both systems and it is solved with the Newton...... series of wind power and power load are used to investigate the mitigation effect of the integrated energy system. At last, the effect of wind power and power demand on the output of Power to Gas (P2G) and gas-fired power generation (GPG) has also been investigated....

  15. Continuous flow synthesis of conjugated polymers.

    Science.gov (United States)

    Seyler, Helga; Jones, David J; Holmes, Andrew B; Wong, Wallace W H

    2012-02-01

    A selection of conjugated polymers, widely studied in organic electronics, was synthesised using continuous flow methodology. As a result of superior heat transfer and reagent control, excellent polymer molecular mass distributions were achieved in significantly reduced reaction times compared to conventional batch reactions.

  16. Continuous-Flow Gas-Phase Bioreactors

    Science.gov (United States)

    Wise, Donald L.; Trantolo, Debra J.

    1994-01-01

    Continuous-flow gas-phase bioreactors proposed for biochemical, food-processing, and related industries. Reactor contains one or more selected enzymes dehydrated or otherwise immobilized on solid carrier. Selected reactant gases fed into reactor, wherein chemical reactions catalyzed by enzyme(s) yield product biochemicals. Concept based on discovery that enzymes not necessarily placed in traditional aqueous environments to function as biocatalysts.

  17. Analytical approach to continuous and intermittent bottleneck flows

    DEFF Research Database (Denmark)

    Helbing, D.; Johansson, A.; Mathiesen, Joachim Kaj;

    2006-01-01

    Many-particle-inspired theory, Continuous and Intermittent Bottleneck Flows Udgivelsesdato: Oct. 20......Many-particle-inspired theory, Continuous and Intermittent Bottleneck Flows Udgivelsesdato: Oct. 20...

  18. Continuous dynamic flow micropumps for microfluid manipulation

    International Nuclear Information System (INIS)

    Recent years have seen considerable progress in the development of microfabricated systems for use in the chemical and biological sciences. The term micro total analytical system (µTAS) is now a well-accepted concept. Much development has been driven by a need to perform effective manipulation of chemical and biological liquids with small volumes at micro and/or nano flowrate level in these systems. In this review, the focus will be on the pumping techniques used for delivery and control of liquids, especially those physical-chemical 'continuous dynamic flow micropumps'. The principles of these pumping techniques are mainly based on one or several well-known phenomena such as electrical, light, magnetic, thermal and other actuated mechanisms. Electrokinetically-driven continuous flow pumps such as the electrophoretic pump and electroosmotic pump, surface chemistry based continuous flow micropumps such as the opto-electrowetting-based pump, optically-driven pump, electrochemical pump and constant gravity-driven pump, and combination-driven techniques such as hydrodynamic flow and electrokinetic/gravity/magnetophoretic pumping will be summarized. The focus will be on the research highlights, trends and future of these pump techniques. Finally, mixing techniques on the microscale are briefly reviewed. (topical review)

  19. A bi-directional DC/DC converter for hybrid wind generator/battery system with state machine control

    Energy Technology Data Exchange (ETDEWEB)

    Hua, C.C.; Liao, Y.C. [National Yunlin Univ. of Science and Technology, Yunlin, Taiwan (China). Dept. of Electrical Engineering

    2008-07-01

    A bi-directional DC to DC converter used in a hybrid wind generator/lead-acid battery power system was presented. A state machine control strategy was used to control both the system power flow and load distribution. It was also used to increase the power capacity of the system. The battery was also charged or discharged through the bi-directional DC to DC converter. Multi-stage current charging control of the batteries was accomplished by adjusting the duty cycle of the power converter. This also improved the charging efficiency by the maximum power point tracking algorithm. It was concluded that the proposed control method can be readily extended to other renewable energy conversion systems. 6 refs., 13 figs.

  20. A bi-directional gap model for simulating the directional thermal radiance of row crops

    Institute of Scientific and Technical Information of China (English)

    CHEN; Liangfu; (陈良富); LIU; Qinhuo; (柳钦火); FAN; Wenjie; (范闻捷); LI; Xiaowen; (李小文); XIAO; Qing; (肖青); YAN; Guangjian; (闫广建); TIAN; Guoliang; (田国良)

    2002-01-01

    Row crops are a kind of typical vegetation canopy between discrete canopy and continuous canopy. Kimes et al. studied the directional thermal radiation of row crops using the geometrical optical model, which simplified row structure as "box" and neglected the gap among foliage and did not consider the emissivity effects. In this work we take account of the gaps along illumination and viewing directions and propose a bi-direction gap model on the basis of the idea of gap probability of discrete vegetation canopy introduced by "Li-Strahler" and inter-correlation of continuous vegetation developed by Kuusk. It can be used to explain "hot spot" effects in thermal infrared region. The gap model has been validated by field experiment on winter wheat planted in shape of rows and results show that the gap model is better than Kimes' model in describing the directionality of thermal infrared emission for row crops.

  1. Continuous microwave flow synthesis of mesoporous hydroxyapatite

    Energy Technology Data Exchange (ETDEWEB)

    Akram, Muhammad; Alshemary, Ammar Z.; Goh, Yi-Fan; Wan Ibrahim, Wan Aini [Department of Chemistry, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Lintang, Hendrik O. [Centre for Sustainable Nanomaterials (CSNano), Ibnu Sina Institute for Scientific and Industrial Research, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia); Hussain, Rafaqat, E-mail: rafaqat@kimia.fs.utm.my [Centre for Sustainable Nanomaterials (CSNano), Ibnu Sina Institute for Scientific and Industrial Research, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor (Malaysia)

    2015-11-01

    We have successfully used continuous microwave flow synthesis (CMFS) technique for the template free synthesis of mesoporous hydroxyapatite. The continuous microwave flow reactor consisted of a modified 2.45 GHz household microwave, peristaltic pumps and a Teflon coil. This cost effective and efficient system was exploited to produce semi-crystalline phase pure nano-sized hydroxyapatite. Effect of microwave power, retention time and the concentration of reactants on the phase purity, degree of crystallinity and surface area of the final product was studied in detail. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to study the phase purity and composition of the product, while transmission electron microscopy (TEM) was used to study the effect of process parameters on the morphology of hydroxyapatite. The TEM analysis confirmed the formation of spherical particles at low microwave power; however the morphology of the particles changed to mesoporous needle and rod-like structure upon exposing the reaction mixture to higher microwave power and longer retention time inside the microwave. The in-vitro ion dissolution behavior of the as synthesized hydroxyapatite was studied by determining the amount of Ca{sup 2+} ion released in SBF solution. - Highlights: • Continuous microwave flow synthesis method was used to prepare hydroxyapatite. • Increase in microwave power enhanced the degree of crystallinity. • TEM images confirmed the presence of mesopores on the surface of HA.

  2. Bi-directional charger for swiss2G - Annual report; Bi-directional charger for swiss2G - Jahresbericht

    Energy Technology Data Exchange (ETDEWEB)

    Schwab, M.; Baumann, P.

    2010-11-15

    This short annual report for 2010 for the Swiss Federal Office of Energy (SFOE) takes a look at a bi-directional charger that can be used in intelligent 'Smart Grid' applications. The idea is based on being able to use electric vehicles as a source of electricity to help meet peak demand for mains electricity. The swiss2G project aims to produce an electric car battery-charger that also functions as an inverter to convert the car's DC battery voltage to mains electricity. The project was started in September 2010. The report describes the aims of the project and reports on initial work done in the areas of safety, switching electronics and AC/DC conversion. National and international co-operation is noted and prospects for further work are discussed.

  3. UWB Bi-directional Bow-tie antenna loaded by rings

    Science.gov (United States)

    Peng, Lin; Sun, Kai; Xie, Ji-yang; Qiu, Yu-jie; Jiang, Xing

    2016-07-01

    Performances of bow-tie antennae can be improved by loading a ring. Specially, the distorted radiation patterns of the reference bow-tie antenna (RBA) at high frequencies become less distorted when a ring is added. That is due to the disciplined current flows trained by the ring. Furthermore, when more rings are loaded, which act as reflectors, higher directivities are obtained and, patterns become bi-directional. Antennae with no ring (RBA), one ring, two rings (three cases), three rings, and four rings are investigated. Research find that loading more rings means better directivity. The directivity of the RBA varies from 2.29 dB to 3.66 dB for the frequency band from 2.5 to 7.5 GHz while the directivity for the four-ring-loaded case varies from 4.27 dB to 7.61 dB in that frequency band.

  4. APLIKASI MIGRASI DATABASE DAN REPLIKASI BI-DIRECTIONAL

    Directory of Open Access Journals (Sweden)

    Michael Yoseph Ricky

    2011-11-01

    Full Text Available This study aims to analyze and design a migration and replication configurations in an enterprise using several methods such as literary study and direc survey to the company; analysis on hangar systems, process migration and replication as well as existing problems; and a prototype design for migration process implementated with Oracle SQL Developer and replication process implementated with Oracle GoldenGate. The study resluts ini a prototype for migration and replication configuration processes using Oracle's Golden Gate which can produce two sets of identical data for backup and recovery. Also a simple tool is designed to assist active-active replication process as well as active-passive one. The migration process from MySQL database to Oracle database using Oracle GoldenGate can not be done because GoldenGate Oracle has bugs related to the binary log, so database migration is done using Oracle SQL Developer. However, bi-directional replication between Oracle database using Oracle GoldenGate can ensure data availability and reduce the workload of primary database.

  5. Continuous microwave flow synthesis of mesoporous hydroxyapatite.

    Science.gov (United States)

    Akram, Muhammad; Alshemary, Ammar Z; Goh, Yi-Fan; Wan Ibrahim, Wan Aini; Lintang, Hendrik O; Hussain, Rafaqat

    2015-11-01

    We have successfully used continuous microwave flow synthesis (CMFS) technique for the template free synthesis of mesoporous hydroxyapatite. The continuous microwave flow reactor consisted of a modified 2.45GHz household microwave, peristaltic pumps and a Teflon coil. This cost effective and efficient system was exploited to produce semi-crystalline phase pure nano-sized hydroxyapatite. Effect of microwave power, retention time and the concentration of reactants on the phase purity, degree of crystallinity and surface area of the final product was studied in detail. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) were used to study the phase purity and composition of the product, while transmission electron microscopy (TEM) was used to study the effect of process parameters on the morphology of hydroxyapatite. The TEM analysis confirmed the formation of spherical particles at low microwave power; however the morphology of the particles changed to mesoporous needle and rod-like structure upon exposing the reaction mixture to higher microwave power and longer retention time inside the microwave. The in-vitro ion dissolution behavior of the as synthesized hydroxyapatite was studied by determining the amount of Ca(2+) ion released in SBF solution.

  6. Renormalization group flows and continual Lie algebras

    CERN Document Server

    Bakas, Ioannis

    2003-01-01

    We study the renormalization group flows of two-dimensional metrics in sigma models and demonstrate that they provide a continual analogue of the Toda field equations based on the infinite dimensional algebra G(d/dt;1). The resulting Toda field equation is a non-linear generalization of the heat equation, which is integrable in target space and shares the same dissipative properties in time. We provide the general solution of the renormalization group flows in terms of free fields, via Backlund transformations, and present some simple examples that illustrate the validity of their formal power series expansion in terms of algebraic data. We study in detail the sausage model that arises as geometric deformation of the O(3) sigma model, and give a new interpretation to its ultra-violet limit by gluing together two copies of Witten's two-dimensional black hole in the asymptotic region. We also provide some new solutions that describe the renormalization group flow of negatively curved spaces in different patches...

  7. Hybrid Amyloid Membranes for Continuous Flow Catalysis.

    Science.gov (United States)

    Bolisetty, Sreenath; Arcari, Mario; Adamcik, Jozef; Mezzenga, Raffaele

    2015-12-29

    Amyloid fibrils are promising nanomaterials for technological applications such as biosensors, tissue engineering, drug delivery, and optoelectronics. Here we show that amyloid-metal nanoparticle hybrids can be used both as efficient active materials for wet catalysis and as membranes for continuous flow catalysis applications. Initially, amyloid fibrils generated in vitro from the nontoxic β-lactoglobulin protein act as templates for the synthesis of gold and palladium metal nanoparticles from salt precursors. The resulting hybrids possess catalytic features as demonstrated by evaluating their activity in a model catalytic reaction in water, e.g., the reduction of 4-nitrophenol into 4-aminophenol, with the rate constant of the reduction increasing with the concentration of amyloid-nanoparticle hybrids. Importantly, the same nanoparticles adsorbed onto fibrils surface show improved catalytic efficiency compared to the same unattached particles, pointing at the important role played by the amyloid fibril templates. Then, filter membranes are prepared from the metal nanoparticle-decorated amyloid fibrils by vacuum filtration. The resulting membranes serve as efficient flow catalysis active materials, with a complete catalytic conversion achieved within a single flow passage of a feeding solution through the membrane.

  8. A chronic generalized bi-directional brain-machine interface

    Science.gov (United States)

    Rouse, A. G.; Stanslaski, S. R.; Cong, P.; Jensen, R. M.; Afshar, P.; Ullestad, D.; Gupta, R.; Molnar, G. F.; Moran, D. W.; Denison, T. J.

    2011-06-01

    A bi-directional neural interface (NI) system was designed and prototyped by incorporating a novel neural recording and processing subsystem into a commercial neural stimulator architecture. The NI system prototype leverages the system infrastructure from an existing neurostimulator to ensure reliable operation in a chronic implantation environment. In addition to providing predicate therapy capabilities, the device adds key elements to facilitate chronic research, such as four channels of electrocortigram/local field potential amplification and spectral analysis, a three-axis accelerometer, algorithm processing, event-based data logging, and wireless telemetry for data uploads and algorithm/configuration updates. The custom-integrated micropower sensor and interface circuits facilitate extended operation in a power-limited device. The prototype underwent significant verification testing to ensure reliability, and meets the requirements for a class CF instrument per IEC-60601 protocols. The ability of the device system to process and aid in classifying brain states was preclinically validated using an in vivo non-human primate model for brain control of a computer cursor (i.e. brain-machine interface or BMI). The primate BMI model was chosen for its ability to quantitatively measure signal decoding performance from brain activity that is similar in both amplitude and spectral content to other biomarkers used to detect disease states (e.g. Parkinson's disease). A key goal of this research prototype is to help broaden the clinical scope and acceptance of NI techniques, particularly real-time brain state detection. These techniques have the potential to be generalized beyond motor prosthesis, and are being explored for unmet needs in other neurological conditions such as movement disorders, stroke and epilepsy.

  9. Upgrade of a transverse ventilation system in a bi-directional tunnel

    Directory of Open Access Journals (Sweden)

    Vidmar Peter

    2012-01-01

    Full Text Available The Karavanke tunnel forms an important link between Slovenia and Austria. The almost 8 km long tunnel is operated with bi-directional traffic and does not have dedicated escape routes. Moreover, the ventilation in case of fire does not satisfy requirements of the EU Directive 2004/54/EC that specifies the minimum requirements for tunnels in the trans-European road network. The paper present results of the research conducted regarding the possibility of upgrade the existing system in order to reach the required level of safety at lower costs possible. It is shown that with simple but novel adaptations of the ventilation system, a sizeable increase in the overall level of safety can be achieved. The methodology applied is a combination of a simple pipe model for tunnel ventilation and for detailed fluid dynamics analysis the CFD model is used. The existing ventilation system that in fire ventilation extracts smoke from a single duct is replaced with the smoke extraction from both ducts applying four axial fans. The analysis is focused on air/smoke flow through the vents and ducts and on pressure drops calculated over the length of the ventilation duct and its influence on the total flow. The change of the flow condition also has influence on ventilation fan operation point that is investigated in the paper as well.

  10. Measuring bi-directional current through a field-effect transistor by virtue of drain-to-source voltage measurement

    Science.gov (United States)

    Turner, Steven Richard

    2006-12-26

    A method and apparatus for measuring current, and particularly bi-directional current, in a field-effect transistor (FET) using drain-to-source voltage measurements. The drain-to-source voltage of the FET is measured and amplified. This signal is then compensated for variations in the temperature of the FET, which affects the impedance of the FET when it is switched on. The output is a signal representative of the direction of the flow of current through the field-effect transistor and the level of the current through the field-effect transistor. Preferably, the measurement only occurs when the FET is switched on.

  11. Behavior of composite rigid frame bridge under bi-directional seismic excitations

    Directory of Open Access Journals (Sweden)

    Xiaogang Liu

    2014-02-01

    Full Text Available Pushover analysis and time history analysis are conducted to explore the bi-directional seismic behavior of composite steel-concrete rigid frame bridge, which is composed of RC piers and steel-concrete composite girders. Both longitudinal and transverse directions excitations are investigated using OpenSees. Firstly, the applicability of pushover analysis based on the fundamental mode is discussed. Secondly, an improved pushover analysis method considering the contribution of higher modes is proposed, and the applicability on composite rigid frame bridges under bi-directional earthquake is verified. Based on this method, an approach to predict the displacement responses of composite rigid frame bridge under random bi-directional seismic excitations by revising the elasto-plastic demand curve is also proposed. It is observed that the developed method yield a good estimate on the responses of composite rigid frame bridges under bi-directional seismic excitations.

  12. Bi-directional Multi Dimension CAP Transmission for Smart Grid Communication Services

    DEFF Research Database (Denmark)

    Zhang, Xu; Binti Othman, Maisara; Pang, Xiaodan;

    2012-01-01

    We experimentally demonstrate bi-directional multi dimension carrierless amplitude and phase (CAP) transmission for smart grid communication services based on optical fiber networks. The proposed system is able to support multi-Gb/s transmission with high spectral efficiency.......We experimentally demonstrate bi-directional multi dimension carrierless amplitude and phase (CAP) transmission for smart grid communication services based on optical fiber networks. The proposed system is able to support multi-Gb/s transmission with high spectral efficiency....

  13. Bi-directional light transmission properties assessment for venetian blinds : Computer simulations compared to photogoniometer measurements

    OpenAIRE

    Andersen, Marilyne; Scartezzini, J.-L.; Rubin, M. D.; Powles, R. C.

    2003-01-01

    An accurate evaluation of daylight distribution through advanced fenestration systems (complex glazing, solar shading systems) requires the knowledge of their Bi-directional light Transmission Distribution Function (BTDF). An innovative equipment for the experimental assessment of these bi-directional functions has been developed, based on a digital imaging detection system. An extensive set of BTDF measurements was performed with this photogoniometer on venetian blinds presenting curved slat...

  14. Low frequency radio observations of bi-directional electron beams in the solar corona

    CERN Document Server

    Carley, Eoin P; Vilmer, Nicole; Gallagher, Peter T

    2015-01-01

    The radio signature of a shock travelling through the solar corona is known as a type II solar radio burst. In rare cases these bursts can exhibit a fine structure known as `herringbones', which are a direct indicator of particle acceleration occurring at the shock front. However, few studies have been performed on herringbones and the details of the underlying particle acceleration processes are unknown. Here, we use an image processing technique known as the Hough transform to statistically analyse the herringbone fine structure in a radio burst at $\\sim$20-90 MHz observed from the Rosse Solar-Terrestrial Observatory on 2011 September 22. We identify 188 individual bursts which are signatures of bi-directional electron beams continuously accelerated to speeds of 0.16$_{-0.10}^{+0.11} c$. This occurs at a shock acceleration site initially at a constant altitude of $\\sim$0.6 R$_{\\odot}$ in the corona, followed by a shift to $\\sim$0.5 R$_{\\odot}$. The anti-sunward beams travel a distance of 170$_{-97}^{+174}$ ...

  15. Low Frequency Radio Observations of Bi-directional Electron Beams in the Solar Corona

    Science.gov (United States)

    Carley, E.; Reid, H.; Vilmer, N.; Gallagher, P.

    2015-12-01

    The radio signature of a shock travelling through the solar corona is known as a type II solar radio burst. In rare cases, these bursts can exhibit a fine structure known as 'herringbones' which are a direct indicator of particle acceleration occurring at the shock front. However, few studies have been performed on herringbones and the details of the underlying particle acceleration processes are unknown. Here, we use an image processing technique known as the Hough transform to statistically analyse the herringbone fine structure in a radio burst at 20-90MHz observed from the Rosse Solar-Terrestrial Observatory on 2011 September 22. We identify 188 individual bursts which are signatures of bi-directional electron beams continuously accelerated to speeds of 0.16 c. This occurs at a shock acceleration site initially at a constant altitude of 0.6 Rsun in the corona, followed by a shift to 0.5 Rsun. The anti-sunward beams travel a distance of 170 Mm (and possibly further) away from the acceleration site, while those travelling toward the sun come to a stop sooner, reaching a smaller distance of 112 Mm. We show that the stopping distance for the sunward beams may depend on the total number density and the velocity of the beam. Our study concludes that a detailed statistical analysis of herringbone fine structure can provide information on the physical properties of the corona which lead to these relatively rare radio bursts.

  16. INFORMATION FLOW ASSURED BY ITC CONTINUITY PLANNING

    Directory of Open Access Journals (Sweden)

    Gabriel Cozgarea

    2009-05-01

    Full Text Available Forwarding the frequent usage of complex processes and the big volume of information, it is imperative to manage the automatic circuit of the document flow in a company activity. The main advantage of such a system consist in document waiting to be proces

  17. Bi-directional magnetic resonance based wireless power transfer for electronic devices

    Science.gov (United States)

    Kar, Durga P.; Nayak, Praveen P.; Bhuyan, Satyanarayan; Mishra, Debasish

    2015-09-01

    In order to power or charge electronic devices wirelessly, a bi-directional wireless power transfer method has been proposed and experimentally investigated. In the proposed design, two receiving coils are used on both sides of a transmitting coil along its central axis to receive the power wirelessly from the generated magnetic fields through strongly coupled magnetic resonance. It has been observed experimentally that the maximum power transfer occurs at the operating resonant frequency for optimum electric load connected across the receiving coils on both side. The optimum wireless power transfer efficiency is 88% for the bi-directional power transfer technique compared 84% in the one side receiver system. By adopting the developed bi-directional power transfer method, two electronic devices can be powered up or charged simultaneously instead of a single device through usual one side receiver system without affecting the optimum power transfer efficiency.

  18. Bi-directional magnetic resonance based wireless power transfer for electronic devices

    Energy Technology Data Exchange (ETDEWEB)

    Kar, Durga P.; Nayak, Praveen P.; Bhuyan, Satyanarayan; Mishra, Debasish [Department of Electronics and Instrumentation Engineering, Institute of Technical Education and Research, Siksha ‘O’ Anushandhan University, Bhubaneswar 751030 (India)

    2015-09-28

    In order to power or charge electronic devices wirelessly, a bi-directional wireless power transfer method has been proposed and experimentally investigated. In the proposed design, two receiving coils are used on both sides of a transmitting coil along its central axis to receive the power wirelessly from the generated magnetic fields through strongly coupled magnetic resonance. It has been observed experimentally that the maximum power transfer occurs at the operating resonant frequency for optimum electric load connected across the receiving coils on both side. The optimum wireless power transfer efficiency is 88% for the bi-directional power transfer technique compared 84% in the one side receiver system. By adopting the developed bi-directional power transfer method, two electronic devices can be powered up or charged simultaneously instead of a single device through usual one side receiver system without affecting the optimum power transfer efficiency.

  19. Detection of Bi-Directionality in Strain-Gage Balance Calibration Data

    Science.gov (United States)

    Ulbrich, Norbert

    2012-01-01

    An indicator variable was developed for both visualization and detection of bi-directionality in wind tunnel strain-gage balance calibration data. First, the calculation of the indicator variable is explained in detail. Then, a criterion is discussed that may be used to decide which gage outputs of a balance have bi- directional behavior. The result of this analysis could be used, for example, to justify the selection of certain absolute value or other even function terms in the regression model of gage outputs whenever the Iterative Method is chosen for the balance calibration data analysis. Calibration data of NASA s MK40 Task balance is analyzed to illustrate both the calculation of the indicator variable and the application of the proposed criterion. Finally, bi directionality characteristics of typical multi piece, hybrid, single piece, and semispan balances are determined and discussed.

  20. Bi-directional magnetic resonance based wireless power transfer for electronic devices

    International Nuclear Information System (INIS)

    In order to power or charge electronic devices wirelessly, a bi-directional wireless power transfer method has been proposed and experimentally investigated. In the proposed design, two receiving coils are used on both sides of a transmitting coil along its central axis to receive the power wirelessly from the generated magnetic fields through strongly coupled magnetic resonance. It has been observed experimentally that the maximum power transfer occurs at the operating resonant frequency for optimum electric load connected across the receiving coils on both side. The optimum wireless power transfer efficiency is 88% for the bi-directional power transfer technique compared 84% in the one side receiver system. By adopting the developed bi-directional power transfer method, two electronic devices can be powered up or charged simultaneously instead of a single device through usual one side receiver system without affecting the optimum power transfer efficiency

  1. Bi-directional WDM transmission by use of SOAs as inline amplifiers without isolators

    DEFF Research Database (Denmark)

    Jeppesen, Palle; Yu, Jianjun

    2001-01-01

    Error-free bi-directional transmission of 8×10 Gb/s signals over two inline SOAs is realized for the first time. It is demonstrated that SOAs can be used for inline amplifiers in bidirectional multi-wavelength transmission systems at 10 Gb/s without any isolator.......Error-free bi-directional transmission of 8×10 Gb/s signals over two inline SOAs is realized for the first time. It is demonstrated that SOAs can be used for inline amplifiers in bidirectional multi-wavelength transmission systems at 10 Gb/s without any isolator....

  2. Transducer-type bi-directional linear ultrasonic motor and experiment

    Institute of Scientific and Technical Information of China (English)

    CHU Xiangcheng; CHEN Zaili

    2002-01-01

    A transducer-type bi-directional linear ultrasonic notor is presented. It has the features of flexible bi-directional drive, simple construction and easy control, etc. The characteristics parameters of the prototype are: frequency 21.46 kHz, maximum moving speed 400 mm/s under pre-load of 3.2 N, maximum thrust 2.1 N under pre-load of 1.6 N. The influence of phase shift and vibration amplitude of ultrasonic transducers on ideal elliptical locus and output characteristics are investigated with theoretical and experimental methods.

  3. Model of Bi-directional Flyback Converter for Hybrid AC/DC Distribution System

    OpenAIRE

    Riku Pasonen

    2013-01-01

    In this article, a simulation model and concept of two switch bi-directional isolated DC/DC converter is presented. Converter is based on flyback converter type. Also control method for voltage regulation with bi-directional power transfer is presented. Target application of the proposed converter was selected to be a hybrid AC/DC distribution system concept of which was briefly described. The requirement of galvanic isolation in the hybrid AC/DC concept comes from use of shared neutral wire;...

  4. A self-adaptive full asynchronous bi-directional transmission channel for network-on-chips

    International Nuclear Information System (INIS)

    To improve two shortcomings of conventional network-on-chips, i.e. low utilization rate in channels between routers and excessive interconnection lines, this paper proposes a full asynchronous self-adaptive bi-directional transmission channel. It can utilize interconnection lines and register resources with high efficiency, and dynamically detect the data transmission state between routers through a direction regulator, which controls the sequencer to automatically adjust the transmission direction of the bi-directional channel, so as to provide a flexible data transmission environment. Null convention logic units are used to make the circuit quasi-delay insensitive and highly robust. The proposed bi-directional transmission channel is implemented based on SMIC 0.18 μm standard CMOS technology. Post-layout simulation results demonstrate that this self-adaptive bi-directional channel has better performance on throughput, transmission flexibility and channel bandwidth utilization compared to a conventional single direction channel. Moreover, the proposed channel can save interconnection lines up to 30% and can provide twice the bandwidth resources of a single direction transmission channel. The proposed channel can apply to an on-chip network which has limited resources of registers and interconnection lines. (semiconductor integrated circuits)

  5. Reliability analysis of an LCL tuned track segmented bi-directional inductive power transfer system

    DEFF Research Database (Denmark)

    Asif Iqbal, S. M.; Madawala, U. K.; Thrimawithana, D. J.;

    2013-01-01

    Bi-directional Inductive Power Transfer (BDIPT) technique is suitable for renewable energy based applications such as electric vehicles (EVs), for the implementation of vehicle-to-grid (V2G) systems. Recently, more efforts have been made by researchers to improve both efficiency and reliability o...

  6. Anxiety and Reading Difficulties in Early Elementary School: Evidence for Unidirectional- or Bi-Directional Relations?

    Science.gov (United States)

    Grills-Taquechel, Amie E.; Fletcher, Jack M.; Vaughn, Sharon R.; Stuebing, Karla K.

    2012-01-01

    The present study examined competing models of the bi-directional influences of anxiety and reading achievement. Participants were 153 ethnically-diverse children (84 male, 69 female) from general education classes evaluated in the winter and spring of their first-grade academic year. Children completed standardized measures of reading achievement…

  7. Longitudinal Bi-Directional Relationships between Sleep and Youth Substance Use

    Science.gov (United States)

    Pasch, Keryn E.; Latimer, Lara A.; Cance, Jessica Duncan; Moe, Stacey G.; Lytle, Leslie A.

    2012-01-01

    Despite the known deficits in sleep that occur during adolescence and the high prevalence of substance use behaviors among this group, relatively little research has explored how sleep and substance use may be causally related. The purpose of this study was to explore the longitudinal bi-directional relationships between sleep duration, sleep…

  8. Properties and Stability of Max-Product Fuzzy Bi-Directional Associative Memory

    Institute of Scientific and Technical Information of China (English)

    SHU Lan

    2005-01-01

    In this paper, a fuzzy operator of max-product is defined at first, and the fuzzy bi-directional associative memory (FBAM) based on the fuzzy operator of max-product is given. Then the properties and the Lyapunov stability of equilibriums of the networks are studied.

  9. Inferring bi-directional interactions between circadian clock genes and metabolism with model ensembles

    NARCIS (Netherlands)

    Grzegorczyk, Marco; Aderhold, Andrej; Husmeier, Dirk

    2015-01-01

    There has been much interest in reconstructing bi-directional regulatory networks linking the circadian clock to metabolism in plants. A variety of reverse engineering methods from machine learning and computational statistics have been proposed and evaluated. The emphasis of the present paper is on

  10. High Efficiency Interleaved Bi-Directional ZVS DC-DC Converter

    DEFF Research Database (Denmark)

    Zafar Ullah Khan, M.; Mohsin Naveed, M.; Hussain, Dil Muhammad Akbar

    2013-01-01

    A High Efficiency Interleaved Bi-Directional ZVS DC-DC converter is presented in this paper. This converter can be operated in both buck and boost mode. CoolMOS is used as a power device to achieve low conduction losses and fast turn off. The value of inductance is selected such that the Cool...

  11. Achievable rate regions and outer bounds for a multi-pair bi-directional relay network

    CERN Document Server

    Kim, Sang Joon; Devroye, Natasha

    2010-01-01

    In a bi-directional relay channel, a pair of nodes wish to exchange independent messages over a shared wireless half-duplex channel with the help of relays. Recent work has mostly considered information theoretic limits of the bi-directional relay channel with two terminal nodes (or end users) and one relay. In this work we consider bi-directional relaying with one base station, multiple terminal nodes and one relay, all of which operate in half-duplex modes. We assume that each terminal node communicates with the base-station in a bi-directional fashion through the relay and do not place any restrictions on the channels between the users, relays and base-stations; that is, each node has a direct link with every other node. Our contributions are three-fold: 1) the introduction of four new temporal protocols which fully exploit the two-way nature of the data and outperform simple routing or multi-hop communication schemes by carefully combining network coding, random binning and user cooperation which exploit ...

  12. Absolute exponential stability analysis of delayed bi-directional associative memory neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Lou Xuyang [Research Center of Control Science and Engineering, Southern Yangtze University, 1800 Lihu Road, Wuxi, Jiangsu 214122 (China); Cui Baotong [Research Center of Control Science and Engineering, Southern Yangtze University, 1800 Lihu Road, Wuxi, Jiangsu 214122 (China)]. E-mail: btcui@sohu.com

    2007-02-15

    The problem of absolute exponential stability for delayed bi-directional associative memory neural networks with time delay is investigated via Lyapunov stability theory. A new sufficient condition ensuring existence and uniqueness of equilibrium and its absolute exponential stability is derived. An illustrative example is given to demonstrate the effectiveness of the obtained results.

  13. Bi-directional Flooding Protocol for Underwater Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Tariq Ali

    2014-05-01

    Full Text Available Underwater Wireless Sensor Networks (UWSNs are getting more importance in the oceanic exploration. The planet earth is basically a planet of water with less than 30% land mass available for humans to live on. However, the areas covered with water are important to mankind for the various resources which have been proven to be valuable. Such resources are gas, oil, marine products which can be used as food and other minerals. In view of the vast area in which these resources can be found, a network of sensors is necessary so that they can be explored. However, sensor networks may not be helpful in the exploration of these resources if they do not have a sufficiently good routing mechanism. Node mobility, 3-D spaces and horizontal communication links are some critical challenges to the researcher in designing new routing protocols for UWSNs. In this study, we have proposed a novel routing protocol called Layer by Layer Angle-Based Flooding (L2-ABF to address the issues of continuous node movements, end-to-end delays and energy consumption. In L2-ABF, every node can calculate its flooding zone to forward data packets toward the sinks without using any explicit configuration or location information. The simulation results show that L2-ABF has some advantages over some existing flooding-based techniques and also can easily manage quick routing changes where node movements are frequent.

  14. Continuous-Flow Biochips: Technology, Physical Design Methods and Testing

    DEFF Research Database (Denmark)

    Pop, Paul; Araci, Ismail Emre; Chakrabarty, Krishnendu

    2015-01-01

    This article is a tutorial on continuous-flow biochips where the basic building blocks are microchannels, and microvalves, and by combining them, more complex units such as mixers, switches, and multiplexers can be built. It also presents the state of the art in flow-based biochip technology...... and emerging research challenges in the areas of physical design and testing techniques....

  15. High-bandwidth continuous-flow arc furnace

    Science.gov (United States)

    Hardt, David E.; Lee, Steven G.

    1996-01-01

    A high-bandwidth continuous-flow arc furnace for stream welding applications includes a metal mass contained in a crucible having an orifice. A power source charges an electrode for generating an arc between the electrode and the mass. The arc heats the metal mass to a molten state. A pressurized gas source propels the molten metal mass through the crucible orifice in a continuous stream. As the metal is ejected, a metal feeder replenishes the molten metal bath. A control system regulates the electrode current, shielding gas pressure, and metal source to provide a continuous flow of molten metal at the crucible orifice. Independent control over the electrode current and shield gas pressure decouples the metal flow temperature and the molten metal flow rate, improving control over resultant weld characteristics.

  16. Tissue Microarray Study of Vasculogenic Mimicry in Bi-directional Differentiated Malignant Tumors

    Institute of Scientific and Technical Information of China (English)

    XishanHao; BaocunSun; ShiwuZhang; XiulanZhao

    2004-01-01

    OBJECTIVE To determine if vasculogenic mimicry (VM) exists in bi-directional differentiated malignant tumors. METHODS The blood supply models for bi-directional differentiated tumors were studied with immunohistochemical and PAS double-staining techniques. New sections were made from 158 paraffin-embedded bi-directional malignant-tumor samples, including melanoma (high malignancy n=30, low malignancy n=30); synoviosarcoma(SS) (high malignancy n=26, low malignancy n=13); acinar rhabdomyosarcoma (All) (high malignancy n=16,low malignancy n=13); malignant mesothelioma (MM) (n=26), and epithelioid sarcoma (ES)(n=4). Tissue microarrays were made. The representative points in the paraffin sections were labeled and two tissue microarrays were made, one included 60 cases of melanoma, and the other included the other tumors. Immunohistochemical staining of the platelet-endothelial cell adhesive molecule(CD31 antigen) and periodic acid Schiff(PAS) staining were conducted. The areas were calculated of vessel-like channels consisting of CD31 antigen-positive tumor cells and of PAS positive materials. The VM was studied using the data obtained. RESULTS Some of these bi-directional tumor cells secreted PAS-positive materials and 0D31 positive materials. The walls of the VM consisted of PAS-positive materials lined with CD31 negative tumor cells with red blood cells inside the channel, whereas the walls of the epithelium-dependent vessels were comprised of CD31 positive materials. The positive areas of CD31 were significantly less than that of PAS (P<0.01). The number of cases with VM in highly malignant tumors was greater than that found in the lowly malignant tumors. CONCLUSIONS Bi-directional differentiated malignant tumor cells have the ability to auto-transform and might interact with the extracellular matrix to form a vessel channel system which mimics blood vessels for transporting blood. That process is called VM. Results in this study show that bi-directional

  17. Defining pulsatility during continuous-flow ventricular assist device support.

    Science.gov (United States)

    Soucy, Kevin G; Koenig, Steven C; Giridharan, Guruprasad A; Sobieski, Michael A; Slaughter, Mark S

    2013-06-01

    Continuous-flow ventricular assist devices (CVADs) have gained widespread use as an effective clinical therapy for patients with advanced-stage heart failure. Axial and centrifugal CVADs have been successfully used as bridge-to-transplant and destination therapy. CVADs are smaller, more reliable, and less complex than the first-generation pulsatile-flow ventricular assist devices. Despite their recent clinical success, arteriovenous malformations, gastrointestinal bleeding, hemorrhagic strokes, aortic valve insufficiency, and valve fusion have been reported in heart failure patients supported by CVADs. It has been hypothesized that diminished arterial pressure and flow pulsatility delivered by CVAD may be a contributing factor to these adverse events. Subsequently, the clinical significance of vascular pulsatility continues to be highly debated. Studies comparing pulsatile-flow and continuous-flow support have presented conflicting findings, largely due to variations in device operation, support duration, and the criteria used to quantify pulsatility. Traditional measurements of pulse pressure and pulsatility index are less effective at quantifying pulsatility for mechanically derived flows, particularly with the growing trend of CVAD speed modulation to achieve various pulsatile flow patterns. Kinetic measurements of energy equivalent pressure and surplus hemodynamic energy can better quantify pulsatile energies, yet technologic and conceptual challenges are impeding their clinical adaption. A review of methods for quantifying vascular pulsatility and their application as a research tool for investigating physiologic responses to CVAD support are presented. PMID:23540401

  18. Identification of a bi-directional promoter from Tomato yellow leaf curl China virus

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A bi-directional promoter of Tomato yellow leaf curl China virus (TYLCCNV) was obtained with the total DNA from TYLCCNV isolate Y10 infected tobacco leaves as a template. Plant expression vectors were constructed by fusing the amplified DNA fragment with the gus gene and nopaline terminator in different orientations. The vectors containing promoter fragments were transferred into leaf cells and plant stems of Nicotiana benthamiana by Agrobacterium-mediated method. Transient expression results showed that both the complementary and virion-sense promoters could drive the gus gene to express, and the GUS activity of the complementary-sense promoter was stronger than that of the virion-sense. Co-expression of the vector containing βC1 gene of TYLCCNV DNAβ with the vector containing a bi-directional promoter revealed that the βC1 protein has no impact on expression of either the virion- or the complementarysense promoter.

  19. Model of Bi-directional Flyback Converter for Hybrid AC/DC Distribution System

    Directory of Open Access Journals (Sweden)

    Riku Pasonen

    2013-12-01

    Full Text Available In this article, a simulation model and concept of two switch bi-directional isolated DC/DC converter is presented. Converter is based on flyback converter type. Also control method for voltage regulation with bi-directional power transfer is presented. Target application of the proposed converter was selected to be a hybrid AC/DC distribution system concept of which was briefly described. The requirement of galvanic isolation in the hybrid AC/DC concept comes from use of shared neutral wire; DC current runs with unbalanced part of AC current in neutral wire. Without galvanic isolation grounded neutral would cause short circuit if DC/DC converter is connected to three phase rectifier or inverter. Simulation was carried out with PSCAD electromagnetic transient simulator.

  20. Sorting and Manipulation of Magnetic Droplets in Continuous Flow

    Science.gov (United States)

    Al-Hetlani, Entesar; Hatt, Oliver J.; Vojtíšek, Martin; Tarn, Mark D.; Iles, Alexander; Pamme, Nicole

    2010-12-01

    We report the rapid on-chip generation and subsequent manipulation of magnetic droplets in continuous flow. Magnetic droplets were formed using aqueous-based ferrofluid as the dispersed phase and fluorocarbon oil as the continuous phase. Droplet manipulation was demonstrated with simple permanent magnets using two microfluidic platforms: (i) flow focusing droplet generation followed by their splitting into daughter droplets containing different amounts of magnetic nanoparticles, and (ii) droplet generation at a T-junction and their downstream deflection across a chamber for sorting based on the applied magnetic field and magnetite loading of the droplet. Both systems show great potential for performing a wide range of high throughput continuous flow processes including sample dilution, cell sorting and screening, and microparticle fabrication.

  1. Inferring bi-directional interactions between circadian clock genes and metabolism with model ensembles

    OpenAIRE

    Grzegorczyk, Marco; Aderhold, Andrej; Husmeier, Dirk

    2015-01-01

    There has been much interest in reconstructing bi-directional regulatory networks linking the circadian clock to metabolism in plants. A variety of reverse engineering methods from machine learning and computational statistics have been proposed and evaluated. The emphasis of the present paper is on combining models in a model ensemble to boost the network reconstruction accuracy, and to explore various model combination strategies to maximize the improvement. Our results demonstrate that a r...

  2. Matrix Converter Bi-directional Switch Power Loss and Cooling Condition Estimation for Integrated Drives

    OpenAIRE

    Sokolovs, A; Galkins, I

    2010-01-01

    In this paper power loss estimation of bi-directional switch of matrix converter is done by means of calculation and experiments. For safe operation of power devices an efficient cooling system of specific device must be designed. This work is part of a greater project of integrated matrix converter AC drives and the cooling problem here is viewed in context of this task. It is necessary to develop a compact power board and cooling system to extract excessive heat from power devices.

  3. BI-DIRECTIONAL COHEN-GROSSBERG NEURAL NETWORK WITH DISCRETE TIME

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Discrete-time version of the bi-directional Cohen-Grossberg neural network is stud-ied in this paper. Some sufficient conditions are obtained to ensure the global exponen-tial stability of such networks with discrete time based on Lyapunov method. These results do not require the symmetry of the connection matrix and the monotonicity, boundedness and differentiability of the activation function.

  4. BI-DIRECTIONAL COHEN-GROSSBERG NEURAL NETWORK WITH DISCRETE TIME

    Institute of Scientific and Technical Information of China (English)

    Du Dejun; Chen Anping

    2009-01-01

    Discrete-time version of the bi-directional Cohen-Grossberg neural network is stu-died in this paper. Some sufficient conditions are obtained to ensure the global ex-ponential stability of such" networks with discrete time based on Lyapunov method. These results do not require the symmetry of the connection matrix and the monoto-nicity, boundedness and differentiability of the activation function.

  5. Upgrade of a transverse ventilation system in a bi-directional tunnel

    OpenAIRE

    Vidmar Peter; Petelin Stojan; Luin Blaž

    2012-01-01

    The Karavanke tunnel forms an important link between Slovenia and Austria. The almost 8 km long tunnel is operated with bi-directional traffic and does not have dedicated escape routes. Moreover, the ventilation in case of fire does not satisfy requirements of the EU Directive 2004/54/EC that specifies the minimum requirements for tunnels in the trans-European road network. The paper present results of the research conducted regarding the possibility of upgrade the existing system in or...

  6. Continuous-flow free acid monitoring method and system

    Science.gov (United States)

    Strain, J.E.; Ross, H.H.

    1980-01-11

    A free acid monitoring method and apparatus is provided for continuously measuring the excess acid present in a process stream. The disclosed monitoring system and method is based on the relationship of the partial pressure ratio of water and acid in equilibrium with an acid solution at constant temperature. A portion of the process stream is pumped into and flows through the monitor under the influence of gravity and back to the process stream. A continuous flowing sample is vaporized at a constant temperature and the vapor is subsequently condensed. Conductivity measurements of the condensate produces a nonlinear response function from which the free acid molarity of the sample process stream is determined.

  7. Development of an efficient bi-directional promoter with tripartite enhancer employing three viral promoters.

    Science.gov (United States)

    Patro, Sunita; Maiti, Indu B; Dey, Nrisingha

    2013-02-10

    We have developed a novel bi-directional promoter (FsFfCBD) by placing two heterogeneous core-promoters from the Figwort mosaic virus sub-genomic transcript promoter (FsCP, -69 to +31) and Cauliflower mosaic virus 35S promoter (CCP, -89 to +1) respectively on upstream (5') and downstream (3') ends of a tri-hybrid enhancer (FsEFfECE), in reverse orientation. The FsEFfECE domain encompasses three heterologous enhancer fragments from Figwort mosaic virus sub-genomic transcript promoter (FsE, 101 bp, -70 to -170), Figwort mosaic virus full-length transcript promoter (FfE, 196 bp, -249 to -54) and Cauliflower mosaic virus 35S promoter (CE, 254 bp, -343 to -90). The bi-directional nature of the FsFfCBD promoter (coupled to GFP and GUS) was established both in transient systems (onion epidermal cells and tobacco protoplasts) and transgenic plant (Nicotiana tabacum samsun NN) by monitoring the simultaneous expression of GFP and GUS employing fluorescence (for GFP) and biochemical (for GUS) based assays. In transgenic plants, the FsFfCBD promoter was found to be 6.8 and 2.5 times stronger than two parent promoters; Fs and FfC respectively. The bi-directional compound promoter FsFfCBD, composed of three heterologous enhancers with enhanced activity could become a valuable additional tool for efficient plant metabolic engineering and molecular pharming. PMID:23183382

  8. The Bi-directional Moving Structures in a Coronal Bright Point

    CERN Document Server

    Li, Dong; Su, Yingna

    2016-01-01

    We report the bi-directional moving structures in a coronal bright point (CBP) on 2015 July 14. It is observed by the Atmospheric Imaging Assembly (AIA) onboard Solar Dynamics Observatory (SDO). This CBP has a lifetime of about 10 minutes, and a curved shape. The observations show that many bright structures are moving intermittently outward from the CBP brightness core. Such moving structures are clearly seen at AIA 171, 193, 211, 131, 94, 335 and 304 A, slit-jaw (SJI) 1330 and 1400 A. In order to analyze these moving structures, the CBP is cut along the moving direction with a curved slit from the AIA and SJI images. Then we can obtain the time-distance slices, including the intensity and intensity-derivative diagrams, from which, the moving structures are recognized as the oblique streaks, and they are characterized by the bi-direction, simultaneity, symmetry, and periodicity. The average speed is around 300 km/s, while the typically period is about 90 s. All these features (including the bi-directional fl...

  9. Development of an efficient bi-directional promoter with tripartite enhancer employing three viral promoters.

    Science.gov (United States)

    Patro, Sunita; Maiti, Indu B; Dey, Nrisingha

    2013-02-10

    We have developed a novel bi-directional promoter (FsFfCBD) by placing two heterogeneous core-promoters from the Figwort mosaic virus sub-genomic transcript promoter (FsCP, -69 to +31) and Cauliflower mosaic virus 35S promoter (CCP, -89 to +1) respectively on upstream (5') and downstream (3') ends of a tri-hybrid enhancer (FsEFfECE), in reverse orientation. The FsEFfECE domain encompasses three heterologous enhancer fragments from Figwort mosaic virus sub-genomic transcript promoter (FsE, 101 bp, -70 to -170), Figwort mosaic virus full-length transcript promoter (FfE, 196 bp, -249 to -54) and Cauliflower mosaic virus 35S promoter (CE, 254 bp, -343 to -90). The bi-directional nature of the FsFfCBD promoter (coupled to GFP and GUS) was established both in transient systems (onion epidermal cells and tobacco protoplasts) and transgenic plant (Nicotiana tabacum samsun NN) by monitoring the simultaneous expression of GFP and GUS employing fluorescence (for GFP) and biochemical (for GUS) based assays. In transgenic plants, the FsFfCBD promoter was found to be 6.8 and 2.5 times stronger than two parent promoters; Fs and FfC respectively. The bi-directional compound promoter FsFfCBD, composed of three heterologous enhancers with enhanced activity could become a valuable additional tool for efficient plant metabolic engineering and molecular pharming.

  10. Shape complexes in continuous max-flow segmentation

    Science.gov (United States)

    Baxter, John S. H.; Yuan, Jing; Drangova, Maria; Peters, Terry M.; Inoue, Jiro

    2016-03-01

    Optimization-based segmentation approaches deriving from discrete graph-cuts and continuous max-flow have become increasingly nuanced, allowing for topological and geometric constraints on the resulting segmentation while retaining global optimality. However, these two considerations, topological and geometric, have yet to be combined in a unified manner. This paper presents the concept of shape complexes, which combine geodesic star convexity with extendable continuous max-flow solvers. These shape complexes allow more complicated shapes to be created through the use of multiple labels and super-labels, with geodesic star convexity governed by a topological ordering. These problems can be optimized using extendable continuous max-flow solvers. Previous work required computationally expensive co-ordinate system warping which are ill-defined and ambiguous in the general case. These shape complexes are validated in a set of synthetic images as well as atrial wall segmentation from contrast-enhanced CT. Shape complexes represent a new, extendable tool alongside other continuous max-flow methods that may be suitable for a wide range of medical image segmentation problems.

  11. Coupled chemo(enzymatic reactions in continuous flow

    Directory of Open Access Journals (Sweden)

    Ruslan Yuryev

    2011-10-01

    Full Text Available This review highlights the state of the art in the field of coupled chemo(enzymatic reactions in continuous flow. Three different approaches to such reaction systems are presented herein and discussed in view of their advantages and disadvantages as well as trends for their future development.

  12. From continuous flow analysis to programmable Flow Injection techniques. A history and tutorial of emerging methodologies.

    Science.gov (United States)

    Ruzicka, Jaromir Jarda

    2016-09-01

    Automation of reagent based assays, also known as Flow Analysis, is based on sample processing, in which a sample flows towards and through a detector for monitoring of its components. The Achilles heel of this methodology is that the majority of FA techniques use constant continuous forward flow to transport the sample - an approach which continually consumes reagents and generates chemical waste. Therefore the purpose of this report is to highlight recent developments of flow programming that not only save reagents, but also lead by means of advanced sample processing to selective and sensitive assays based on stop flow measurement. Flow programming combined with a novel approach to data harvesting yields a novel approach to single standard calibration, and avoids interference caused by refractive index. Finally, flow programming is useful for sample preparation, such as rapid, extensive sample dilution. The principles are illustrated by selected references to an available online tutorial http://www.flowinjectiontutorial,com/. PMID:27343609

  13. Visualization periodic flows in a continuously stratified fluid.

    Science.gov (United States)

    Bardakov, R.; Vasiliev, A.

    2012-04-01

    To visualize the flow pattern of viscous continuously stratified fluid both experimental and computational methods were developed. Computational procedures were based on exact solutions of set of the fundamental equations. Solutions of the problems of flows producing by periodically oscillating disk (linear and torsion oscillations) were visualized with a high resolutions to distinguish small-scale the singular components on the background of strong internal waves. Numerical algorithm of visualization allows to represent both the scalar and vector fields, such as velocity, density, pressure, vorticity, stream function. The size of the source, buoyancy and oscillation frequency, kinematic viscosity of the medium effects were traced in 2D an 3D posing problems. Precision schlieren instrument was used to visualize the flow pattern produced by linear and torsion oscillations of strip and disk in a continuously stratified fluid. Uniform stratification was created by the continuous displacement method. The buoyancy period ranged from 7.5 to 14 s. In the experiments disks with diameters from 9 to 30 cm and a thickness of 1 mm to 10 mm were used. Different schlieren methods that are conventional vertical slit - Foucault knife, vertical slit - filament (Maksoutov's method) and horizontal slit - horizontal grating (natural "rainbow" schlieren method) help to produce supplementing flow patterns. Both internal wave beams and fine flow components were visualized in vicinity and far from the source. Intensity of high gradient envelopes increased proportionally the amplitude of the source. In domains of envelopes convergence isolated small scale vortices and extended mushroom like jets were formed. Experiments have shown that in the case of torsion oscillations pattern of currents is more complicated than in case of forced linear oscillations. Comparison with known theoretical model shows that nonlinear interactions between the regular and singular flow components must be taken

  14. Modeling the distribution of ammonia across Europe including bi-directional surface-atmosphere exchange

    Directory of Open Access Journals (Sweden)

    R. J. Wichink Kruit

    2012-04-01

    Full Text Available A large shortcoming of current chemistry transport models for simulating the fate of ammonia in the atmosphere is the lack of a description of the bi-directional surface-atmosphere exchange. In this paper, results of an update of the dry deposition module DEPAC in the LOTOS-EUROS model are discussed. It is shown that with the new description, which includes bi-directional surface-atmosphere exchange, the modeled ammonia concentrations increase almost everywhere, in particular in agricultural source areas. The reason is that by using a compensation point the ammonia life time and transport distance is increased. As a consequence, deposition of ammonia and ammonium decreases in agricultural source areas, while it increases in large nature areas and remote regions especially in Southern Scandinavia. The inclusion of a compensation point for water reduces the dry deposition over sea and allows reproducing the observed marine background concentrations at coastal locations to a better extend. A comparison with measurements shows that the model results better represent the measured ammonia concentrations. The concentrations in nature areas are slightly overestimated, while the concentrations in agricultural source areas are still underestimated. Although the introduction of the compensation point improves the model performance, the modeling of ammonia remains challenging. Important aspects are emission patterns in space and time as well as a proper approach to deal with the high concentration gradients in relation to model resolution. In short, the inclusion of a bi-directional surface atmosphere exchange is a significant step forward for modeling ammonia.

  15. Compartmentalized Droplets for Continuous Flow Liquid-Liquid Interface Catalysis.

    Science.gov (United States)

    Zhang, Ming; Wei, Lijuan; Chen, Huan; Du, Zhiping; Binks, Bernard P; Yang, Hengquan

    2016-08-17

    To address the limitations of batch organic-aqueous biphasic catalysis, we develop a conceptually novel method termed Flow Pickering Emulsion, or FPE, to process biphasic reactions in a continuous flow fashion. This method involves the compartmentalization of bulk water into micron-sized droplets based on a water-in-oil Pickering emulsion, which are packed into a column reactor. The compartmentalized water droplets can confine water-soluble catalysts, thus "immobilizing" the catalyst in the column reactor, while the interstices between the droplets allow the organic (oil) phase to flow. Key fundamental principles underpinning this method such as the oil phase flow behavior, the stability of compartmentalized droplets and the confinement capability of these droplets toward water-soluble catalysts are experimentally and theoretically investigated. As a proof of this concept, case studies including a sulfuric acid-catalyzed addition reaction, a heteropolyacid-catalyzed ring opening reaction and an enzyme-catalyzed chiral reaction demonstrate the generality and versatility of the FPE method. Impressively, in addition to the excellent durability, the developed FPE reactions exhibit up to 10-fold reaction efficiency enhancement in comparison to the existing batch reactions, indicating a unique flow interface catalysis effect. This study opens up a new avenue to allow conventional biphasic catalysis reactions to access more sustainable and efficient flow chemistry using an innovative liquid-liquid interface protocol. PMID:27429173

  16. Continuous-Flow N-Heterocyclic Carbene Generation and Organocatalysis.

    Science.gov (United States)

    Di Marco, Lorenzo; Hans, Morgan; Delaude, Lionel; Monbaliu, Jean-Christophe M

    2016-03-18

    Two methods were assessed for the generation of common N-heterocyclic carbenes (NHCs) from stable imidazol(in)ium precursors using convenient and straightforward continuous-flow setups with either a heterogeneous inorganic base (Cs2 CO3 or K3 PO4 ) or a homogeneous organic base (KN(SiMe3 )2 ). In-line quenching with carbon disulfide revealed that the homogeneous strategy was most efficient for the preparation of a small library of NHCs. The generation of free nucleophilic carbenes was next telescoped with two benchmark NHC-catalyzed reactions; namely, the transesterification of vinyl acetate with benzyl alcohol and the amidation of N-Boc-glycine methyl ester with ethanolamine. Both organocatalytic transformations proceeded with total conversion and excellent yields were achieved after extraction, showcasing the first examples of continuous-flow organocatalysis with NHCs. PMID:26880372

  17. Modelling of Serpentine Continuous Flow Polymerase Chain Reaction Microfluidics

    Directory of Open Access Journals (Sweden)

    Abubakar Mohammed

    2012-03-01

    Full Text Available The continuous flow Polymerase Chain Reaction (PCR microfluidics DNA amplification device is a recent discovery aimed at eliminating the cyclic hold experienced while using the alternative stationary device.The Application of Computational Fluid Dynamics is increasingly growing and can help achieve optimal designs before actual fabrication. This paper presents a CFD modelling of a continuous flow serpentine PCR device with narrow and wider channels. There are two temperature regions at 950C and 600C for denaturation and annealing respectively. Extension is achieved along the middle of the channel at 720C owing to temperature gradient. The model require a pressure of 42.6KPa for a 30 cycle amplification.

  18. Continuous-flow sheathless diamagnetic particle separation in ferrofluids

    Science.gov (United States)

    Zhou, Yilong; Song, Le; Yu, Liandong; Xuan, Xiangchun

    2016-08-01

    Separating particles from a complex mixture is often necessary in many chemical and biomedical applications. This work presents a continuous-flow sheathless diamagnetic particle separation in ferrofluids through U-shaped microchannels. Due to the action of a size-dependent magnetic force, diamagnetic particles are focused into a single stream in the inlet branch of the U-turn and then continuously separated into two streams in its outlet branch. A 3D numerical model is developed to predict and understand the diamagnetic particle transport during this separation process. The numerical predictions are found to agree well with the experimental observations in a systematic study of the effects of multiple parameters including ferrofluid flow rate, concentration and magnet-channel distance. Additional numerical studies of the geometric effects of the U-turn reveal that increasing the outlet-branch width of the U-turn can significantly enhance the diamagnetic particle separation in ferrofluids.

  19. Optimization of Bi-Directional Flyback Converter for a High Voltage Capacitor Charging Application

    DEFF Research Database (Denmark)

    Thummala, Prasanth; Schneider, Henrik; Zhang, Zhe;

    2014-01-01

    This paper presents an optimization technique for a flyback converter with a bidirectional energy transfer. The main goal is to optimize the converter for driving an incremental dielectric electro active polymer actuator, which must be charged and discharged from 0 V to 2500 V DC, supplied from...... for this application. The efficiency and loss distribution results provided by the optimization routine provide a deep insight into the transformer design and its impact on total converter efficiency. Finally, experimental work on a prototype of the bi-directional flyback converter is presented. The maximum charging...... and discharging energy efficiencies of the optimized design, are 96.1% and 85%, respectively....

  20. Analysis of global exponential stability for a class of bi-directional associative memory networks

    Institute of Scientific and Technical Information of China (English)

    王宏霞; 何晨

    2003-01-01

    In real-time applications of bi-directional associative memory (BAM) networks, a global exponentially stable equilibrium is highly desired. The existence, uniqueness and global exponential stability for a class of BAM networks are studied in this paper, the signal function of neurons is assumed to be piece-wise linear from the engineering point of view. A very concise condition for the equilibrium of such a network being globally exponentially stable is derived,which makes the practical design of this kind of networks an easy job.

  1. Study on Application of Bi-directional Combination Technology Integrating Residue Hydrotreating with Catalytic Cracking RICP

    Institute of Scientific and Technical Information of China (English)

    Niu Chuanfeng; Gao Yongcan; Dai Lishun; Li Dadong

    2008-01-01

    After analysing the disadvantages of the traditional residue hydrotreating-catalytic cracking combination process, RIPP has proposed a bi-directional combination technology integrating residue hydrotreating with catalytic cracking called RICP which does not further recycles the FCC heavy cycle oil (HCO) inside the FCC unit and delivers HCO to the residue hydrotreating unit as a diluting oil for the residue that is concurrently subjected to hydrotreating prior to being used as the FCC feed oil. The RICP technology can stimulate residue hydrotreating reactions through utilization of HCO along with an increased yield of FCC light distillate, resulting in enhanced petroleum utilization and economic benefits of the refinery.

  2. Method and apparatus for continuous flow injection extraction analysis

    Energy Technology Data Exchange (ETDEWEB)

    Hartenstein, Steven D. (Idaho Falls, ID); Siemer, Darryl D. (Idaho Falls, ID)

    1992-01-01

    A method and apparatus for a continuous flow injection batch extraction aysis system is disclosed employing extraction of a component of a first liquid into a second liquid which is a solvent for a component of the first liquid, and is immiscible with the first liquid, and for separating the first liquid from the second liquid subsequent to extraction of the component of the first liquid.

  3. Development of a continuous-flow fluidic pump

    International Nuclear Information System (INIS)

    A study was made of a fluidic pump which utilizes gas pistons, a venturi-like reverse-flow-diverter, and a planar Y-type flow junction to produce a continuous flow of liquid from a system containing no moving parts. The study included an evaluation of the system performance and of methods for controlling the stability of the fluidic system. A mathematical model of the system was developed for steady-state operation using accepted theories of fluid mechanics. Although more elaborate models are needed for detailed design and optimization of specific systems, the model determined some of the main factors controlling the system performance and will be used in the development of more accurate models. 49 refs., 39 figs., 9 tabs

  4. iGC2: an architecture for micro gas chromatographs utilizing integrated bi-directional pumps and multi-stage preconcentrators

    International Nuclear Information System (INIS)

    This paper reports an integrated micro gas chromatography (µGC) architecture which utilizes a bi-directional micropump. Four integral components-–the bi-directional Knudsen pump (KP2), a two-stage preconcentrator-focuser (PCF2), a separation column, and a gas detector-–are integrated in a 4.3 cm3 stack, forming a serial flow path. All four components are fabricated using the same three-mask process. Compared to the conventional approach used with multi-stage preconcentrators, in which valves are used to reverse flow between the sampling phase and the separation phase, this µGC architecture reduces the overall complexity. In this architecture, the vapors being sampled are drawn through the detector and column before reaching the PCF2. The microsystem operation is experimentally validated by quantitative analyses of benzene, toluene, and xylene vapors ranging in concentration from 43–1167 mg m−3. (paper)

  5. Flow of Steel in Mold Region During Continuous Casting

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xing-guo; ZHANG Wen-xiao; JIN Jun-ze; J. W. Evans

    2007-01-01

    The particle image velocimetry (PIV) technique was used to study the fluid flow phenomena that occurred during continuous casting, using a water model with dimensions of 1 840 mm×280 mm. Two types of solidified shells, i.e., the smooth type and the coarse type, were used to characterize the dendrite in order to simulate different liquid-solid interfacial conditions. The influence of the nozzle angle and the immersion depth of nozzle, as well as the casting speed on the flow behavior was investigated quantitatively. The results were as follows: (1) There are two large recirculations above and below the fluid jet in the mold, respectively, under the smooth interface condition. However, in the case of the dendrite solidified shell, it was found that the flow velocity of the fluid decreased and more smaller vortices appeared in the upper region of the mold. (2) The angle and the immersion depth of nozzle are two important factors affecting the flow pattern, and they are also capable of bringing about the change in the flow direction. (3) The higher the casting speed, the higher are the jet stream and the impacting point on the narrow face. However, the high casting speed causes serious fluctuation of the meniscus, and correspondingly leads to various defects.

  6. Moral judgment modulation by disgust is bi-directionally moderated by individual sensitivity

    Directory of Open Access Journals (Sweden)

    How Hwee eOng

    2014-03-01

    Full Text Available Modern theories of moral judgment predict that both conscious reasoning and unconscious emotional influences affect the way people decide about right and wrong. In a series of experiments, we tested the effect of subliminal and conscious priming of disgust facial expressions on moral dilemmas. Trolley-car-type scenarios were used, with subjects rating how acceptable they found the utilitarian course of action to be. On average, subliminal priming of disgust facial expressions resulted in higher rates of utilitarian judgments compared to neutral facial expressions. Further, in replication, we found that individual change in moral acceptability ratings due to disgust priming was modulated by individual sensitivity to disgust, revealing a bi-directional function. Our second replication extended this result to show that the function held for both subliminally and consciously presented stimuli. Combined across these experiments, we show a reliable bi-directional function, with presentation of disgust expression primes to individuals with higher disgust sensitivity resulting in more utilitarian judgments (i.e., number-based and presentations to individuals with lower sensitivity resulting in more deontological judgments (i.e., rules-based. Our results may reconcile previous conflicting reports of disgust modulation of moral judgment by modeling how individual sensitivity to disgust determines the direction and degree of this effect.

  7. Review and parameterisation of bi-directional ammonia exchange between vegetation and the atmosphere

    Science.gov (United States)

    Massad, R.-S.; Nemitz, E.; Sutton, M. A.

    2010-11-01

    Current deposition schemes used in atmospheric chemical transport models do not generally account for bi-directional exchange of ammonia (NH3). Bi-directional exchange schemes, which have so far been applied at the plot scale, can be included in transport models, but need to be parameterised with appropriate values of the ground layer compensation point (χg), stomatal compensation point (χs) and cuticular resistance (Rw). We review existing measurements of χg, χs as well as Rw and compile a comprehensive dataset from which we then propose generalised parameterisations. χs is related to Γs, the non-dimensional ratio of [NH4+]apo and [H+]apo in the apoplast, through the temperature dependence of the combined Henry and dissociation equilibrium. The meta-analysis suggests that the nitrogen (N) input is the main driver of the apoplastic and bulk leaf concentrations of ammonium (NH4 apomodel for example). In principle, the parameterisations should be applicable to other climates, though there is a need for more underpinning data, with the uncertainties being especially large for tropical and subtropical conditions.

  8. Flow Patterns in a Continuous Glass-Making Furnace

    International Nuclear Information System (INIS)

    Investigations have been made with 51Cr on the flow patterns in a glass-making furnace containing 720 tons of melt and operating continuously with six sheet-glass drawing machines. The radioactive tracer was injected rapidly through the left-side feeder-pocket of the furnace in the form of chromium oxide. The tracer was dissolved in the glass-melt and the path of this labelled melt was detected by sampling and subsequently measuring the activity of the samples. Sampling was performed on three opposite points of the left and right sides of the furnace respectively, partly from the melt, and partly from the edge of the product sheet every two hours throughout 24 days. However, samples were also taken at the left-side sampling points every quarter of an hour of the first three days. During the entire investigation, 2500 samples were tested. The specific activities of the samples in terms of time, i.e. the distribution of the residence-time of the isotope 51Cr, well represent the flow of the melt for different sampling positions. From these functions an average flow rate of 0.16-0.19 m/h can be calculated for the different parts of the furnace. The areas between the curves and the abscissa which are proportional to the quantity of the tracer passing through the sampling points are not equal. Comparing these areas one can see that at 10 m from the feeder-pocket the flow rate is highest in the centre of the tank. Fifty-six per cent of the melt flowing along the sides of the tank is from the material fed in on the same side whereas the other 44% is from that on the opposite side. At 24 m from the feeder-pocket the flow is uniform over the whole cross-section of the furnace and in the forked part (so-called forehearth) the flow rate depends on the ratio between the glass production of the left and right side machines. The descending and ascending branches of the curves of the distribution functions are described by equations which hold for backmix flow-type reactors with

  9. Fluid Flow in Continuous Casting Mold with a Configured Nozzle

    Institute of Scientific and Technical Information of China (English)

    王镭; 沈厚发; 柳百成

    2004-01-01

    The influence of a configured nozzle on the turbulent fluid flow in a continuous casting mold was investigated using the simulation program Visual Cast, which used the finite difference method and the SIMPLER algorithm. CAD software was used to construct the complicated nozzle in the calculational region. The simulation accuracy was validated by comparison with the classic driven cavity flow problem. The simulation results agree well with water modeling experiments. The simulations show that the velocity distribution at the nozzle port is uneven and the jet faces downward more than the nozzle outlet. Simulations with a configured nozzle and the inlet velocity at the nozzle entrance give precise results and overcome the traditional difficulty in determining the nozzle outlet velocity.

  10. Multistep Continuous-Flow Synthesis in Medicinal Chemistry

    DEFF Research Database (Denmark)

    Petersen, Trine P; Mirsharghi, Sahar; Rummel, Pia Cwarzko;

    2013-01-01

    A three-step continuous-flow synthesis system and its application to the assembly of a new series of chemokine receptor ligands directly from commercial building blocks is reported. No scavenger columns or solvent switches are necessary to recover the desired test compounds, which were obtained i...... studies in medicinal chemistry....... in overall yields of 49-94 %. The system is modular and flexible, and the individual steps of the sequence can be interchanged with similar outcome, extending the scope of the chemistry. Biological evaluation confirmed activity on the chemokine CCR8 receptor and provided initial structure...

  11. Use Of Infrared Imagery In Continuous Flow Wind Tunnels

    Science.gov (United States)

    Stallings, D. W.; Whetsel, R. G.

    1983-03-01

    Thermal mapping with infrared imagery is a very useful test technique in continuous flow wind tunnels. Convective-heating patterns over large areas of a model can be obtained through remote sensing of the surface temperature. A system has been developed at AEDC which uses a commercially available infrared scanning camera to produce these heat-transfer maps. In addition to the camera, the system includes video monitors, an analog tape recording, an analog-to-digital converter, a digitizer control, and two minicomputers. This paper will describe the individual components, data reduction techniques, and typical applications. *

  12. Flow and Temperature Fields in Slab Continuous Casting Molds

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In order to develop super-board and super-thick slabs, the flow and temperature fields were studied in slab continuous casting molds under different practical conditions, such as slab dimensions, with-drawing slab speed, design of nozzles, and superheat temperature. The results showed that it is preferred to incline nozzle bores downwards and the submerged depth of the nozzles is best kept between 250€?300 mm. In addition, the solidified shell is thicker at the wide face than that at the narrow face, while the thin points along the wide face exist both in the center and in the some area toward each respective end.

  13. Graphene-based battery electrodes having continuous flow paths

    Science.gov (United States)

    Zhang, Jiguang; Xiao, Jie; Liu, Jun; Xu, Wu; Li, Xiaolin; Wang, Deyu

    2014-05-24

    Some batteries can exhibit greatly improved performance by utilizing electrodes having randomly arranged graphene nanosheets forming a network of channels defining continuous flow paths through the electrode. The network of channels can provide a diffusion pathway for the liquid electrolyte and/or for reactant gases. Metal-air batteries can benefit from such electrodes. In particular Li-air batteries show extremely high capacities, wherein the network of channels allow oxygen to diffuse through the electrode and mesopores in the electrode can store discharge products.

  14. Response of piping system on friction support to bi-directional excitation

    International Nuclear Information System (INIS)

    Installation of friction devices between a piping system and its supporting medium is an effective way of energy dissipation in the piping systems. In this paper, seismic effectiveness of friction type support for a piping system subjected to two horizontal components of earthquake motion is investigated. The interaction between the mobilized restoring forces of the friction support is duly considered. The non-linear behavior of the restoring forces of the support is modeled as an elastic-perfectly plastic system with a very high value of initial stiffness. Such an idealization avoids keeping track of transitional rules (as required in conventional modeling of friction systems) under arbitrary dynamic loading. The frictional forces mobilized at the friction support are assumed to be dependent on the sliding velocity and instantaneous normal force acting on the support. A detailed systematic procedure for analysis of piping systems supported on friction support considering the effects of bi-directional interaction of the frictional forces is presented. The proposed procedure is validated by comparing the analytical seismic responses of a spatial piping system supported on a friction support with the corresponding experimental results. The responses of the piping system and the frictional forces of the support are observed to be in close agreement with the experimental results validating the proposed analysis procedure. It was also observed that the friction supports are very effective in reducing the seismic response of piping systems. In order to investigate the effects of bi-directional interaction of the frictional forces, the seismic responses of the piping system are compared by considering and ignoring the interaction under few narrow-band and broad-band (real earthquake) ground motions. The bi-directional interaction of the frictional forces has significant effects on the response of piping system and should be included in the analysis of piping systems

  15. Continuous measurements of real-life bidirectional pedestrian flows on a wide walkway

    CERN Document Server

    Corbetta, Alessandro; Lee, Chung-min; Toschi, Federico

    2016-01-01

    Employing partially overlapping overhead \\kinectTMS sensors and automatic pedestrian tracking algorithms we recorded the crowd traffic in a rectilinear section of the main walkway of Eindhoven train station on a 24/7 basis. Beside giving access to the train platforms (it passes underneath the railways), the walkway plays an important connection role in the city. Several crowding scenarios occur during the day, including high- and low-density dynamics in uni- and bi-directional regimes. In this paper we discuss our recording technique and we illustrate preliminary data analyses. Via fundamental diagrams-like representations we report pedestrian velocities and fluxes vs. pedestrian density. Considering the density range $0$ - $1.1\\,$ped/m$^2$, we find that at densities lower than $0.8\\,$ped/m$^2$ pedestrians in unidirectional flows walk faster than in bidirectional regimes. On the opposite, velocities and fluxes for even bidirectional flows are higher above $0.8\\,$ped/m$^2$.

  16. High Resolution Continuous Flow Analysis System for Polar Ice Cores

    Science.gov (United States)

    Dallmayr, Remi; Azuma, Kumiko; Yamada, Hironobu; Kjær, Helle Astrid; Vallelonga, Paul; Azuma, Nobuhiko; Takata, Morimasa

    2014-05-01

    In the last decades, Continuous Flow Analysis (CFA) technology for ice core analyses has been developed to reconstruct the past changes of the climate system 1), 2). Compared with traditional analyses of discrete samples, a CFA system offers much faster and higher depth resolution analyses. It also generates a decontaminated sample stream without time-consuming sample processing procedure by using the inner area of an ice-core sample.. The CFA system that we have been developing is currently able to continuously measure stable water isotopes 3) and electrolytic conductivity, as well as to collect discrete samples for the both inner and outer areas with variable depth resolutions. Chemistry analyses4) and methane-gas analysis 5) are planned to be added using the continuous water stream system 5). In order to optimize the resolution of the current system with minimal sample volumes necessary for different analyses, our CFA system typically melts an ice core at 1.6 cm/min. Instead of using a wire position encoder with typical 1mm positioning resolution 6), we decided to use a high-accuracy CCD Laser displacement sensor (LKG-G505, Keyence). At the 1.6 cm/min melt rate, the positioning resolution was increased to 0.27mm. Also, the mixing volume that occurs in our open split debubbler is regulated using its weight. The overflow pumping rate is smoothly PID controlled to maintain the weight as low as possible, while keeping a safety buffer of water to avoid air bubbles downstream. To evaluate the system's depth-resolution, we will present the preliminary data of electrolytic conductivity obtained by melting 12 bags of the North Greenland Eemian Ice Drilling (NEEM) ice core. The samples correspond to different climate intervals (Greenland Stadial 21, 22, Greenland Stadial 5, Greenland Interstadial 5, Greenland Interstadial 7, Greenland Stadial 8). We will present results for the Greenland Stadial -8, whose depths and ages are between 1723.7 and 1724.8 meters, and 35.520 to

  17. A distributed optical fiber bi-directional strain-displacement sensor

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A distributed optical fiber strain-displacement sensor is developed, which consists of an optical fiber gauge of strain-displacement and an optical time domain reflectometer (OTDR). The operational principle is the modulation of fiber loss in OTDR, i.e. the strain and displacement in monitoring position are obtained from the bending loss of optical fiber bonded on the optical fiber gauge of strain-displacement. After examining the strain and displacement in the cantilever and the micro displacement rack respectively, the result indicates that the distributed optical fiber gauge of strain-displacement can monitor strains or displacements in different sensitive lengths. The key technique for measuring bi-directional strain-displacement is the pretreatment of bending of the freely suspended optical fibers, which can be identified with OTDR by inserting time delay optical fiber.

  18. Bi-directional causality in California's electricity and natural-gas markets

    International Nuclear Information System (INIS)

    The Granger instantaneous-causality test is applied to explore the potential causal relationships between wholesale electricity and natural-gas prices in California. The test shows these relationships to be bi-directional, and reveals California's electricity and natural-gas markets to be as inextricably intertwined as casual observation and theoretical considerations would suggest they ought to be. This meshing of markets exacerbated the effects of California's natural-gas crisis on the contemporaneous electricity crisis, while concurrently the electricity crisis may have contributed to the dysfunction in the national-gas market and helped to precipitate the natural-gas crisis. The finding supports an integrated approach, as opposed to a piecemeal approach, for formulating energy policy recommendations, not just in California but in the world at large. (author)

  19. A multi-layered vascular scaffold with symmetrical structure by bi-directional gradient electrospinning.

    Science.gov (United States)

    Wu, Tong; Huang, Chen; Li, Dawei; Yin, Anlin; Liu, Wei; Wang, Jing; Chen, Jianfeng; Ei-Hamshary, Hany; Al-Deyab, Salem S; Mo, Xiumei

    2015-09-01

    Multi-layered scaffolds are advantageous in vascular tissue engineering, in consideration of better combination of biomechanics, biocompatibility and biodegradability than the scaffolds with single structure. In this study, a bi-directional gradient electrospinning method was developed to fabricate poly(l-lactide-co-caprolactone) (P(LLA-CL)), collagen and chitosan based tubular scaffold with multi-layered symmetrical structure. The multi-layered composite scaffold showed improved mechanical property and biocompatibility, in comparison to the blended scaffold using the same proportion of raw materials. Endothelialization on the multi-layered scaffold was accelerated owing to the bioactive surface made of pure natural materials. hSMCs growth showed the similar results because of its better biocompatibility. Additionally, fibers morphology change, pH value balance and long term mechanical support results showed that the gradient structure effectively improved biodegradability. PMID:26101818

  20. High efficiency interleaved bi-directional ZVS DC-DC converter

    Science.gov (United States)

    Zafarullah Khan, M.; Mohsin Naveed, M.; Akbar Hussain, D. M.

    2013-06-01

    A high efficiency interleaved bi-directional ZVS DC-DC converter is presented in this paper. This converter can be operated in both buck and boost mode. CoolMOS is used as a power device to achieve low conduction losses and fast turn off. The value of inductance is selected such that the CoolMOS drain-to-source voltage always falls to zero before it turns on and ZVS is achieved. Multiphase interleaved inductors are used to achieve high power and low ripple currents. Converter is operated at 50kHz and MATLAB Simulink simulation is performed. 6kW prototype converter is implemented in buck mode and simulation results are verified.

  1. Inference of biological networks using Bi-directional Random Forest Granger causality.

    Science.gov (United States)

    Furqan, Mohammad Shaheryar; Siyal, Mohammad Yakoob

    2016-01-01

    The standard ordinary least squares based Granger causality is one of the widely used methods for detecting causal interactions between time series data. However, recent developments in technology limit the utilization of some existing implementations due to the availability of high dimensional data. In this paper, we are proposing a technique called Bi-directional Random Forest Granger causality. This technique uses the random forest regularization together with the idea of reusing the time series data by reversing the time stamp to extract more causal information. We have demonstrated the effectiveness of our proposed method by applying it to simulated data and then applied it to two real biological datasets, i.e., fMRI and HeLa cell. fMRI data was used to map brain network involved in deductive reasoning while HeLa cell dataset was used to map gene network involved in cancer. PMID:27186478

  2. Regenerative Strategy for Sum-rate Enhancement in Bi-directional Three-node Cooperation

    Institute of Scientific and Technical Information of China (English)

    Hu Ning; Zhong Xiaofeng; Zhao Ming; Wang Jing

    2009-01-01

    In bi-directional three-node cooperation, one regenerative strategy with network coding and power optimization is proposed for system sum-rate under a total energy constraint. In this paper, the network coding and power optimization are applied to improve system sum-rate. But max-min optimization problem in power allocation is a NP-hard problem. In high Signal-to-Noise Ratio regime, this NP-hard problem is transformed into constrained polynomial optimization problem, which can be computed in polynomial time. Although it is a suboptimal solution, numerical simulations show that this strategy enhances the system sum-rate up to 45% as compared to a traditional four-phase strategy, and up to 13% as compared to the three-phase strategy without power optimization.

  3. A possible mechanism for self coordination of bi-directional traffic across nuclear pores

    CERN Document Server

    Kapon, Ruti; Mukamel, David; Reich, and Ziv

    2008-01-01

    Nuclear pore complexes are constantly confronted by large fluxes of macromolecules and macromolecular complexes that need to get into and out of the nucleus. Such bi-directional traffic occurring in a narrow channel can easily lead to jamming. How then is passage between the nucleus and cytoplasm maintained under the varying conditions that arise during the lifetime of the cell? Here, we address this question using computer simulations in which the behaviour of the ensemble of transporting cargoes is analyzed under different conditions. We suggest that traffic can exist in two distinct modes, depending on concentration of cargoes and dissociation rates of the transport receptor-cargo complexes from the pores. In one mode, which prevails when dissociation is quick and cargo concentration is low, transport in either direction proceeds uninterrupted by the other direction. The result is that overall-traffic-direction fluctuates rapidly and unsystematically between import and export. Remarkably, when cargo concen...

  4. Demonstration and experimental evaluation of a bi-directional 10-GHz microwave photonic filter

    Science.gov (United States)

    Zaldívar-Huerta, I. E.; Correa-Mena, A. G.; Hernández-Nava, P.; García-Juárez, A.; Rodríguez-Asomoza, J.; Lee, Min Won

    2016-09-01

    A bi-directional 10-GHz microwave photonic filter is proposed and experimentally evaluated. Its frequency response consists of a series of microwave band-pass windows obtained by the interaction of externally modulated multimode laser diodes emitting around of 1550 nm associated to the chromatic dispersion parameter of an optical fiber, as well as the length of the optical link. Microwave band-pass windows exhibit on average a-3 dB bandwidth of 378 MHz. This electro-optical system shows an efficient configuration and good performance. Potentially, filtered microwave signals can be used as electrical carriers in optical communication systems to transmit and distribute services such as video, voice and data.

  5. Power system transient stability simulation based on module bi-directional iteration

    Institute of Scientific and Technical Information of China (English)

    FANG; Dazhong; YANG; Xiaodong

    2005-01-01

    A new simultaneous solution method using module bi-directional iteration is proposed for power system transient stability simulation. In this method, power network is partitioned into a tree hierarchy; computation modules are established for decomposed power networks and various power system components respectively. Through representing every computation module by a computation node, a computation tree is constructed by connecting the nodes together according to their electrical relations in power systems. A tree-traversing procedure called forward reduction and backward evaluation is performed to calculate correction factors of the variables in Newton iterations. This high-efficiency simulation method is feasible to be applied in parallel computation for large interconnected systems. Simulation tests are conducted on the New England 10-generator test power system and the North China-Northeast interconnected system, and the results are compared with those of the commercial software BPA to validate the effectiveness and correctness of this method.

  6. Identifying missing and spurious connections via the bi-directional diffusion on bipartite networks

    Science.gov (United States)

    Zhang, Peng; Zeng, An; Fan, Ying

    2014-06-01

    Link prediction and spurious link detection in complex networks have attracted increasing attention from both physical and computer science communities, due to their wide applications in many real systems. Related previous works mainly focus on monopartite networks while these problems in bipartite networks are not yet systematically addressed. Containing two different kinds of nodes, bipartite networks are essentially different from monopartite networks, especially in node similarity calculation: the similarity between nodes of different kinds (called inter-similarity) is not well defined. In this letter, we employ the local diffusion processes to measure the inter-similarity in bipartite networks. We find that the inter-similarity is asymmetric if the diffusion is applied in different directions. Accordingly, we propose a bi-directional hybrid diffusion method which is shown to achieve higher accuracy than the existing diffusion methods in identifying missing and spurious links in bipartite networks.

  7. Bi-directional conversion between microwave and optical frequencies in a piezoelectric optomechanical device

    Science.gov (United States)

    Vainsencher, Amit; Satzinger, K. J.; Peairs, G. A.; Cleland, A. N.

    2016-07-01

    We describe the principles of design, fabrication, and operation of a piezoelectric optomechanical crystal with which we demonstrate bi-directional conversion of energy between microwave and optical frequencies. The optomechanical crystal has an optical mode at 1523 nm co-located with a mechanical breathing mode at 3.8 GHz, with a measured optomechanical coupling strength gom/2π of 115 kHz. The breathing mode is driven and detected by curved interdigitated transducers that couple to a Lamb mode in suspended membranes on either end of the optomechanical crystal, allowing the external piezoelectric modulation of the optical signal as well as the converse, the detection of microwave electrical signals generated by a modulated optical signal. We compare measurements to theory where appropriate.

  8. Clinico-serologic co-relation in bi-directional ABO incompatible hemopoietic stem cell transplantation

    Directory of Open Access Journals (Sweden)

    Sabita Basu

    2015-01-01

    Full Text Available Background: The ABO blood group system is of prime significance in red cell transfusion and organ transplantation. However, ABO compatibility is not critical in allogenic hemopoietic stem cell transplantation (HSCT and approximately 40-50% of hemopoietic stem cell transplants are ABO incompatible. This incompatibility may be major, minor or bi-directional. Though there are descriptions of transfusion practice and protocols in ABO incompatible HSCT, there are considerable variations and transfusion support in these patients can be very challenging. Aims: The immunohematologic observations in two cases of bi-directional ABO incompatible HSCT have been described, and clinico-serologic correlation has been attempted. Materials and Methods: In both cases, peripheral blood stem cell harvests were obtained using the Cobe spectra cell separator. Immunohematologic assessments in the donor and recipient were done as a part of pre HSCT evaluation. Both the standard tube technique and column agglutination method (Ortho Biovue Micro Bead System was used. Antibody screen was done by column agglutination method using three cell panel (Surgiscreen cells. Isoagglutinin titration was done by the master dilution method and standard validated techniques were used. Results: The pattern of laboratory findings in the two cases was different and so were the clinical outcomes. Although there was early engraftment in the first case, the second case developed pure red cell aplasia and this was well-reflected in the immunohematologic assessments. Conclusion: Immunohematologic assessment correlated well with the clinical picture and could be used to predict clinical outcome and onset of complications in ABO incompatible HSCT.

  9. An Experimental Investigation of the Responses of Classic Spar Platform Subjected to Bi-directional Waves

    Directory of Open Access Journals (Sweden)

    V.J. Kurian

    2015-01-01

    Full Text Available The effect of the bi-directional short-crested waves on the dynamic motion responses of the moored classic spar is demonstrated from the results of the models test in this study. Practically in the design of offshore structures, long-crested or 2-dimensional wave properties that propagated to one direction are considered. Even though such long-crested wave is widely used for the design purposes, it is hardly determined in the real sea. The wind generated sea state in the real sea conditions are indeed well represented by the short-crested waves. Short-crested waves are defined as linear summation of long-crested wave series that propagated to different directions. Hence, the motions of the model were investigated experimentally by conducting the wave tank tests in the wave tank of Offshore Laboratory of Universiti Teknologi PETRONAS. Five groups of bi-directional wave series were defined and exerted on the classic spar model, which fabricated by using steel with scaling factor of 1:100. From the results measured, it was found that similar trends of the responses in term of Response Amplitude Operator (RAO for surge, heave and pitch motions were obtained. Maximum responses of surge, heave and pitch were found due to wave crossing angle 90°, while minimum response was found due to wave crossing angle 135°, respectively. It could be concluded that the wave crossing angle 90° (BD3 gives the widest spreading for short crested waves, while the wave crossing angle 135° (BD4 gives the narrowest spreading for short crested waves.

  10. Continuous-Flow Detector for Rapid Pathogen Identification

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, Louise M. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Microfluidics; Skulan, Andrew J. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Microfluidics; Singh, Anup K. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Microfluidics; Cummings, Eric B. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Microfluidics; Fiechtner, Gregory J. [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Microfluidics

    2006-09-01

    This report describes the continued development of a low-power, portable detector for the rapid identification of pathogens such as B. anthracis and smallpox. Based on our successful demonstration of the continuous filter/concentrator inlet, we believe strongly that the inlet section will enable differentiation between viable and non-viable populations, between types of cells, and between pathogens and background contamination. Selective, continuous focusing of particles in a microstream enables highly selective and sensitive identification using fluorescently labeled antibodies and other receptors such as peptides, aptamers, or small ligands to minimize false positives. Processes such as mixing and lysing will also benefit from the highly localized particle streams. The concentrator is based on faceted prisms to contract microfluidic flows while maintaining uniform flowfields. The resulting interfaces, capable of high throughput, serve as high-, low-, and band-pass filters to direct selected bioparticles to a rapid, affinity-based detection system. The proposed device is superior to existing array-based detectors as antibody-pathogen binding can be accomplished in seconds rather than tens of minutes or even hours. The system is being designed to interface with aerosol collectors under development by the National Laboratories or commercial systems. The focused stream is designed to be interrogated using diode lasers to differentiate pathogens by light scattering. Identification of particles is done using fluorescently labeled antibodies to tag the particles, followed by multiplexed laser-induced fluorescence (LIF) detection (achieved by labeling each antibody with a different dye).

  11. Continuous-flow chemiluminometric determination of some tetracyclines

    International Nuclear Information System (INIS)

    Chemiluminescence is found to be generated by action of lucigenin or hexacyanoferrate(III) on tetracyclines. The reaction with lucigenin exhibits chemiluminescence after alkaline degradation of tetracyclines to the corresponding iso derivatives. The reaction with hexacyanoferrate (III) occurs after acidic degradation of tetracyclines to corresponding anhydro derivatives. The chemiluminescence reaction takes place in alkaline medium, and allows the development of a continuous-flow method for the determination of 1.00-10.0 μgml-1 oxytetracycline and doxycycline. When applied to commercial formulations, the procedure was relatively free from interferences from common excipients. The results obtained for the assay of dosage forms compared well with those obtained by the official methods and demonstrated good accuracy and precision. (author). 32 refs.; 5 figs.; 6 tabs

  12. Continuous-flow chemiluminometric determination of some tetracyclines

    Energy Technology Data Exchange (ETDEWEB)

    Syropoulos, A.B.; Calokerinos, A.C. (University of Athens (greece). Laboratory of Analytical Chemistry)

    1991-12-24

    Chemiluminescence is found to be generated by action of lucigenin or hexacyanoferrate(III) on tetracyclines. The reaction with lucigenin exhibits chemiluminescence after alkaline degradation of tetracyclines to the corresponding iso derivatives. The reaction with hexacyanoferrate (III) occurs after acidic degradation of tetracyclines to corresponding anhydro derivatives. The chemiluminescence reaction takes place in alkaline medium, and allows the development of a continuous-flow method for the determination of 1.00-10.0 {mu}gml{sup -1} oxytetracycline and doxycycline. When applied to commercial formulations, the procedure was relatively free from interferences from common excipients. The results obtained for the assay of dosage forms compared well with those obtained by the official methods and demonstrated good accuracy and precision. (author). 32 refs.; 5 figs.; 6 tabs.

  13. Continuous flow ink etching for direct micropattern of silicon dioxide

    Science.gov (United States)

    Xing, Jiyao; Rong, Weibin; Wang, Lefeng; Sun, Lining

    2016-07-01

    A continuous flow ink etching (CFIE) method is presented to directly create micropatterns on a 60 nm thick silicon dioxide (SiO2) layer. This technique employs a micropipette filled with potassium bifluoride (KHF2) aqueous solution to localize SiO2 dissolution in the vicinity of the micropipette tip. Both dot and line features with well-defined edges were fabricated and used as hardmasks for silicon etching. The linear density of etchant ink deposited on the SiO2 can be used to regulate the depth, width and 2D morphology of the line pattern. The characterization of CFIE including the resolution (about 4 μm), reproducibility and capability to form complex structures are reported. This technique provides a simple and flexible alternative to generate the SiO2 hardmask for silicon microstructure fabrication.

  14. Transition and Continuance in Science Production: Authorship Flow in Chemistry

    Directory of Open Access Journals (Sweden)

    Mahsa Nikzad

    2016-03-01

    Full Text Available The aim of this article is to study authorship flow in Iranian ISI articles in the field of chemistry based on Price’s model. Price divided authors in each given period in any field into four groups including newcomers, transients, continuants, and terminators. He maintained that actuarial statistics could be applied to authorship to calculate death rate and birth rate in scientific fields. A total 25,573 articles written by 59,661 Iranian chemistry authors between 1973 and 2012 were downloaded from Web of Science and were subjected to statistical analysis. The average birth rate was 66.7%, the average death rate was 19.4%, infant mortality rate was 51.2%, average natural increase was 47.3%, the average life expectancy was 1.98 years and the longest scientific age was 22 years. The results show that although a large number of people start their scientific activity, the number of those who terminate their activity in the same year as they start (infant death rate is also large and little continuity exist in publishing activities of Iranian chemists. The overall labor force in the field of chemistry in Iran was not satisfactory as the majority of authors in each period are transients. Policy makers need to take measures to improve the situation.

  15. Manually-powered continuous-flow maize-sheller

    Energy Technology Data Exchange (ETDEWEB)

    Nkakini, S.O.; Ayotamuno, M.J.; Maeba, G.P.D. [Agricultural and Environmental Engineering Department, Rivers State University of Science and Technology, Port Harcourt. P.M.B. 5080, Rivers State (Nigeria); Ogaji, S.O.T.; Probert, S.D. [School of Engineering, Cranfield University, Bedfordshire MK43 OAL (United Kingdom)

    2007-12-15

    This sheller uses abrasion between a rotating shelling-disc and stationary concave compartments to achieve the stripping. A manually-operated handle is used to rotate two shafts, one of which translates rotational motion to become linear motion of a slider crank. The slider pushes the maize cobs into the sheller continually one after another. Though manually operated, the sheller can provide a continuous flow; the kernels being collected via a chute. At a speed of 60 rpm, a shelling effectiveness of 67% was achieved, with a low kernel-breakage factor of 0.090 and a throughput of 6.82 kg/h. For the trial runs, the machine was designed to shell a batch of 100 maize cobs, which were introduced into the feed hopper in one batch, without stopping until all the cobs were stripped via the shelling unit. This design is preferred, because of its rapid operation, low human-energy expenditure, low breakage-factor for the kernels as well as relatively little dust being emitted during shelling; hence leading to a relatively-healthier local atmosphere for the operator. Its wider use is therefore recommended. (author)

  16. Continuous-flow metal biosorption in a regenerable Sargassum column.

    Science.gov (United States)

    Volesky, B; Weber, J; Park, J M

    2003-01-01

    Metal biosorption behavior of raw seaweed S. filipendula in ten consecutive sorption-desorption cycles has been investigated in a packed-bed flow-through column during a continuous removal of copper from a 35mg/L aqueous solution at pH 5. The elutant used was a 1% (w/v) CaCl2/HCl-solution at pH 3. The sorption and desorption was carried out for an average of 85 and 15h, respectively, representing more than 41 days of continuous use of the biosorbent. The weight loss of biomass after this time was 21.6%. The Cu-biosorption capacity of the biomass, based on the initial dry weight, remained relatively constant at approximately 38 mg Cu/g. Loss of sorption performance was indicated by a shortening breakthrough time and a broadening mass-transfer zone. The column service time, considered up to 1 mg Cu/L in the effluent, decreased continuously from 25.4 h for the first to 12.7 h for the last cycle. The critical bed length, representing the mass-transfer zone, increased almost linearly from 28 to 34cm. "Life-factors" for S. filipendula were found to be 0.0008h(-1) for the breakthrough time and 0.008cm/h for the critical bed length, using an exponential decay and linear fitting functions, respectively. Regeneration with CaCl2/HCl at pH 3 provided elution efficiencies up to 100%. Maximum concentration factors were determined to be in the range 16-44, a decreasing tendency was observed with an increasing exposure time. PMID:12502059

  17. ROLE OF LEAF SURFACE WATER IN THE BI-DIRECTIONAL AMMONIA EXCHANGE BETWEEN THE ATMOSPHERE AND TERRESTRIAL BIOSPHERE

    Science.gov (United States)

    A field experiment was conducted to study the ammonia exchange between plants and the atmosphere in a soybean field in Duplin County, North Carolina during the summer of 2002. Measurements indicate that the net canopy-scale ammonia exchange is bi-directional and has a significant...

  18. Dielectric Electro Active Polymer Incremental Actuator Driven by Multiple High-Voltage Bi-directional DC-DC Converters

    DEFF Research Database (Denmark)

    Thummala, Prasanth; Zhang, Zhe; Andersen, Michael A. E.;

    2013-01-01

    capacitive sub-actuators. It needs to be driven by three high voltage (~2.5 kV) DC-DC converters, to achieve the linear incremental motion. The topology used for this application is a bi-directional flyback DC-DC converter. The control of the incremental actuator involves, implementation of digital...

  19. Performance Impairments due to Gain Transients in a Raman-based Bi-directional Long-reach PON Link

    DEFF Research Database (Denmark)

    Kjær, Rasmus; Tafur Monroy, Idelfonso; Jensen, Jesper Bevensee;

    2007-01-01

    A Raman-based bi-directional long-reach passive optical network (PON) link was proposed and had shown to be very robust toward WDM channel add/drops and therefore look promising for future high-capacity fiber-to-the-premises (FTTP) systems with bursty traffic. Penalty measurements on a weak data...

  20. 78 FR 65306 - Best Practices for Continuous Monitoring of Temperature and Flow in Wadeable Streams

    Science.gov (United States)

    2013-10-31

    ... Development. The report describes best practices for the deployment of continuous temperature and flow sensors... AGENCY Best Practices for Continuous Monitoring of Temperature and Flow in Wadeable Streams AGENCY... Continuous Monitoring of Temperature and Flow in Wadeable Streams'' (EPA/600/R-13/170). The EPA also...

  1. Arginine bi-directional translocation and breakdown into ornithine along the arbuscular mycorrhizal mycelium

    Institute of Scientific and Technical Information of China (English)

    JIN HaiRu

    2009-01-01

    Bi-directional translocatlon and degradation of Arginine (Arg) along the arbuscular mycorrhizal (AM) fungal mycellum were testified through 15N and/or 13C isotopic labeling. In vitro mycorrhizas of Glomus intraradices and Ri T-DNA-transformed carrot roots were grown in dual compartment Petri dishes. [15N-and/or13C]Arg was supplied to either the fungal compartment or the mycorrhizal compartment or separate dishes containing the uncolonized roots. The levels and labeling of free amino acids (AAs) in the mycorrhizal roots and in the extraradical mycelia(ERM) were measured by gas chromatogra-phy/mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). The ERM of AM fungi exposed in either NH4+ or urea as sole external nitrogen source had much higher 15N enrichment of Arg, compared with those In nitrate or exogenous Arg; however, glycerol supplied as an external car-bon source to the ERM had no significant effect on the level of Arg in the ERM. Meanwhile, Arg bio-synthesized In the ERM could be translocated intact to the mycorrhizal roots and thereby the level of Arg in the mycorrhizal roots increased to about 20% after culture of ERM in 4 mmol/L NH4+ for 6 weeks.Also Arg was found to be bi-directionally transported along the AM fungal mycelium through [U-13C]Arg labeling either In the mycorrhizal compartment or in the fungal compartment. Once Arg was translo-cated to the potential N-limited sites, it would be further degraded into ornithine (Orn) and urea since either [U-13C] or [U-15N/U-13C]Orn was apparently shown up in the mycorrhizal root tissues when [U-13C] or [U-15N/U-13C]Arg was labeled In the fungal compartment, respectively. Evidently Orn formation indi-cated the ongoing activities of Arg translocation and degradation through the urea cycle in AM fungal mycelium.

  2. Arginine bi-directional translocation and breakdown into ornithine along the arbuscular mycorrhizal mycelium

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Bi-directional translocation and degradation of Arginine (Arg) along the arbuscular mycorrhizal (AM) fungal mycelium were testified through 15N and/or 13C isotopic labeling. In vitro mycorrhizas of Glomus intraradices and Ri T-DNA-transformed carrot roots were grown in dual compartment Petri dishes. [15N- and/or13C]Arg was supplied to either the fungal compartment or the mycorrhizal compartment or separate dishes containing the uncolonized roots. The levels and labeling of free amino acids (AAs) in the mycorrhizal roots and in the extraradical mycelia(ERM) were measured by gas chromatogra- phy/mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). The ERM of AM fungi exposed in either NH4+ or urea as sole external nitrogen source had much higher 15N enrichment of Arg, compared with those in nitrate or exogenous Arg; however, glycerol supplied as an external car- bon source to the ERM had no significant effect on the level of Arg in the ERM. Meanwhile, Arg bio- synthesized in the ERM could be translocated intact to the mycorrhizal roots and thereby the level of Arg in the mycorrhizal roots increased to about 20% after culture of ERM in 4 mmol/L NH4+ for 6 weeks. Also Arg was found to be bi-directionally transported along the AM fungal mycelium through [U-13C]Arg labeling either in the mycorrhizal compartment or in the fungal compartment. Once Arg was translo- cated to the potential N-limited sites, it would be further degraded into ornithine (Orn) and urea since either [U-13C] or [U-15N/U-13C]Orn was apparently shown up in the mycorrhizal root tissues when [U-13C] or [U-15N/U-13C]Arg was labeled in the fungal compartment, respectively. Evidently Orn formation indi- cated the ongoing activities of Arg translocation and degradation through the urea cycle in AM fungal mycelium.

  3. Continuous-flow leaching studies of crushed and cored SYNROC

    International Nuclear Information System (INIS)

    Both crushed (150 to 300 μm) and cored (1.8 mm diameter) samples of SYNROC have been leached with the single-pass continuous-flow leaching equipment. Crushed samples of Cs-hollandite were also leached in a similar experiment. Temperatures used were 25 and 750C and leachates were 0.03 N NaHCO3 and distilled water. Leaching rates from SYNROC C were ranked Cs > Sr greater than or equal to Ca > Ba > Zr. A comparison of leaching rates is made between crushed SYNROC, cored SYNROC, and PNL 76-68 glass beads. This comparison depends on how the surface areas are determined for each sample. Based on geometric surface areas for SYNROC cores and glass beads Cs leach rates from SYNROC compare well with both Na and Np leached from the glass. The other elements leached from SYNROC are lower than Na and Np leached from glass. They also vary for each element while glass shows nearly the same leach rate for both Na and Np

  4. Hydrothermal upgrading of algae paste in a continuous flow reactor.

    Science.gov (United States)

    Patel, Bhavish; Hellgardt, Klaus

    2015-09-01

    This investigation demonstrates the utility of a novel laboratory scale continuous plug flow reactor for fast Hydrothermal Liquefaction (HTL) of microalgae in a quartz lined chamber. Reactions were carried out between 300 and 380 °C and residence times of 0.5-4 min. Cyclohexane was used as a co-solvent to enhance extraction and prevent char formation. Highest biocrude yield of 38 wt.% was achieved at 380 °C and 30 s as well as Water Soluble Fraction containing up to 60 wt.% matter recovered. Analysis of the biocrude showed that the extent of deoxygenation and denitrogenation after HTL varied and is dependent on the reaction conditions, Fourier Transform Infrared Spectroscopy analysis showed that biocrude contains similar functional moieties with only a small difference observed at different reaction conditions. Conversely, the Simulated Distillation and Size Exclusion Chromatography data showed that harsher conditions produced marginally better biocrude with improved boiling point profile and lower molecular weight compounds, respectively which was confirmed using Gas Chromatography-Mass Spectrometry. PMID:25908412

  5. A Bi-Directional Refinement Algorithm for the Calculus of (Co)Inductive Constructions

    CERN Document Server

    Asperti, Andrea; Coen, Claudio Sacerdoti; Tassi, Enrico

    2012-01-01

    The paper describes the refinement algorithm for the Calculus of (Co)Inductive Constructions (CIC) implemented in the interactive theorem prover Matita. The refinement algorithm is in charge of giving a meaning to the terms, types and proof terms directly written by the user or generated by using tactics, decision procedures or general automation. The terms are written in an "external syntax" meant to be user friendly that allows omission of information, untyped binders and a certain liberal use of user defined sub-typing. The refiner modifies the terms to obtain related well typed terms in the internal syntax understood by the kernel of the ITP. In particular, it acts as a type inference algorithm when all the binders are untyped. The proposed algorithm is bi-directional: given a term in external syntax and a type expected for the term, it propagates as much typing information as possible towards the leaves of the term. Traditional mono-directional algorithms, instead, proceed in a bottom-up way by inferring...

  6. Inferring bi-directional interactions between circadian clock genes and metabolism with model ensembles.

    Science.gov (United States)

    Grzegorczyk, Marco; Aderhold, Andrej; Husmeier, Dirk

    2015-04-01

    There has been much interest in reconstructing bi-directional regulatory networks linking the circadian clock to metabolism in plants. A variety of reverse engineering methods from machine learning and computational statistics have been proposed and evaluated. The emphasis of the present paper is on combining models in a model ensemble to boost the network reconstruction accuracy, and to explore various model combination strategies to maximize the improvement. Our results demonstrate that a rich ensemble of predictors outperforms the best individual model, even if the ensemble includes poor predictors with inferior individual reconstruction accuracy. For our application to metabolomic and transcriptomic time series from various mutagenesis plants grown in different light-dark cycles we also show how to determine the optimal time lag between interactions, and we identify significant interactions with a randomization test. Our study predicts new statistically significant interactions between circadian clock genes and metabolites in Arabidopsis thaliana, and thus provides independent statistical evidence that the regulation of metabolism by the circadian clock is not uni-directional, but that there is a statistically significant feedback mechanism aiming from metabolism back to the circadian clock. PMID:25719342

  7. Bi-directional modulation of AMPA receptor unitary conductance by synaptic activity

    Directory of Open Access Journals (Sweden)

    Matthews Paul

    2004-11-01

    Full Text Available Abstract Background Knowledge of how synapses alter their efficiency of communication is central to the understanding of learning and memory. The most extensively studied forms of synaptic plasticity are long-term potentiation (LTP and its counterpart long-term depression (LTD of AMPA receptor-mediated synaptic transmission. In the CA1 region of the hippocampus, it has been shown that LTP often involves a rapid increase in the unitary conductance of AMPA receptor channels. However, LTP can also occur in the absence of any alteration in AMPA receptor unitary conductance. In the present study we have used whole-cell dendritic recording, failures analysis and non-stationary fluctuation analysis to investigate the mechanism of depotentiation of LTP. Results We find that when LTP involves an increase in unitary conductance, subsequent depotentiation invariably involves the return of unitary conductance to pre-LTP values. In contrast, when LTP does not involve a change in unitary conductance then depotentiation also occurs in the absence of any change in unitary conductance, indicating a reduction in the number of activated receptors as the most likely mechanism. Conclusions These data show that unitary conductance can be bi-directionally modified by synaptic activity. Furthermore, there are at least two distinct mechanisms to restore synaptic strength from a potentiated state, which depend upon the mechanism of the previous potentiation.

  8. Bi-directional Effects of Peer Relationships and Adolescent Substance Use: A Longitudinal Study.

    Science.gov (United States)

    McDonough, Meghan H; Jose, Paul E; Stuart, Jaimee

    2016-08-01

    Understanding the predictors of the onset and maintenance of substance use in adolescence is important because it is a recognized health risk. The present longitudinal study examined whether negative peer influence and peer connectedness predicted changes in adolescent alcohol, cigarette, marijuana, and other illegal drug use, and reciprocally whether substance use predicted changes in peer relationships. Adolescents (N = 1940; 52 % female; 52 % European New Zealanders, 30 % Maori, 12 % Pacific Islander) aged 10-15 years completed measures annually for 3 years. Cross-lagged panel models were used to examine bi-directional effects. Negative peer influence predicted increased use of all substances. In turn, alcohol, cigarette, and marijuana use predicted increased negative peer influence, but this effect was inconsistent over time. Peer connectedness, predicted to diminish the frequency of substance use, was found to be unrelated to it. Breaking the reciprocal cycle between peer coercion and substance use would seem to be useful for reducing substance use. PMID:26391360

  9. Current understanding of the bi-directional relationship of major depression with inflammation

    Directory of Open Access Journals (Sweden)

    Messay Berhane

    2012-02-01

    Full Text Available Abstract Consistent evidence links major depression and its affective components to negative health outcomes. Although the pathways of these effects are likely complex and multifactorial, recent evidence suggests that innate inflammatory processes may play a role. An overview of current literature suggests that pathways between negative moods and inflammation are bi-directional. Indeed, negative moods activate peripheral physiologic mechanisms that result in an up regulation of systemic levels of inflammation. Conversely, peripheral inflammatory mediators signal the brain to affect behavioral, affective and cognitive changes that are consistent with symptoms of major depressive disorder. It is likely that these pathways are part of a complex feedback loop that involves the nervous, endocrine, and immune systems and plays a role in the modulation of peripheral inflammatory responses to central and peripheral stimuli, in central responses to peripheral immune activation and in the maintenance of homeostatic balance. Further research is warranted to fully understand the role of central processes in this feedback loop, which likely contributes to the pathophysiology of mental and physical health.

  10. Possible bi-directional link between ETA receptors and protein kinase C in rat blood vessels

    Directory of Open Access Journals (Sweden)

    A. M. Northover

    1995-01-01

    Full Text Available Possible links have been investigated between activation of protein kinase C (PKC and endothelin (ET production by small blood vessels. Perfusion pressures were recorded from rat isolated mesenteric artery, with or without the small intestine attached, before and after addition to the perfusate of either ET-1, ET-3 or the PKC activator 12-deoxyphorbol 13-phenylacetate (DOPPA. Rises in perfusion pressure in response to ET-1 (10−8 Mor DOPPA (10−6 M were reduced significantly by pre-treatment with either the ETA receptor antagonist PD151242 (10−6 M or the PKC inhibitor Ro 31-8220 (10−6 M. ET-3 (10−8 M had a significant, albeit small, effect only when the gut was still attached to the mesentery. Inthis latter preparation ET-1 and DOPPA increased the permeability of villi microvessels to colloidal carbon in the perfusate. This effect of DOPPA was reduced by pre-treatment with either PD151242 or Ro 31-8220, but the effects of ET-1 were reduced significantly only by Ro 31-8220. ET-3 (10−8 M was without effect. The results suggest a possible bi-directional link between ETA receptors and PKC in the intestinal vasculature.

  11. Efficient Parallel and Out of Core Algorithms for Constructing Large Bi-directed de Bruijn Graphs

    CERN Document Server

    Kundeti, Vamsi; Dinh, Hieu

    2010-01-01

    Assembling genomic sequences from a set of overlapping reads is one of the most fundamental problems in computational biology. Algorithms addressing the assembly problem fall into two broad categories -- based on the data structures which they employ. The first class uses an overlap/string graph and the second type uses a de Bruijn graph. However with the recent advances in short read sequencing technology, de Bruijn graph based algorithms seem to play a vital role in practice. Efficient algorithms for building these massive de Bruijn graphs are very essential in large sequencing projects based on short reads. In Jackson et. al. ICPP-2008, an $O(n/p)$ time parallel algorithm has been given for this problem. Here $n$ is the size of the input and $p$ is the number of processors. This algorithm enumerates all possible bi-directed edges which can overlap with a node and ends up generating $\\Theta(n\\Sigma)$ messages. In this paper we present a $\\Theta(n/p)$ time parallel algorithm with a communication complexity e...

  12. On-chip free-flow magnetophoresis: Separation and detection of mixtures of magnetic particles in continuous flow

    NARCIS (Netherlands)

    Pamme, Nicole; Eijkel, Jan C.T.; Manz, Andreas

    2006-01-01

    The complete separation of mixtures of magnetic particles was achieved by on-chip free-flow magnetophoresis. In continuous flow, magnetic particles were deflected from the direction of larninar flow by a perpendicular magnetic field depending on their magnetic susceptibility and size and on the flow

  13. 4x10Gb/s WDM Bi-directional Gating in a Semiconductor Optical Amplifier by Using Polarization Multiplexing Technique

    DEFF Research Database (Denmark)

    Yu, Jianjun; Jeppesen, Palle

    2000-01-01

    Bi-directional SOA gating can further reduce the number of gating elements in the space switch, we demonstrate that a conventional SOA employing polarization multiplexing technique (PMT) can be used for bi-directional WDM gating operation at 10Gb/s....

  14. Comparison of plateletpheresis on three continuous flow cell separators

    Directory of Open Access Journals (Sweden)

    Tendulkar Anita

    2009-01-01

    Full Text Available Introduction: Platelet concentrate (PC remains one of the most important support measures in thrombocytopenic patients. An efficient cell separator is a prerequisite for an optimally functioning apheresis setup. Donor blood count may undergo a temporary reduction after the procedure. Aim: The aim was to find the extent of reduction in donor blood count (hemoglobin, hematocrit, white blood cell, and platelet after plateletpheresis and to evaluate the cell separator for collection efficiency, processing time, and leukoreduction. Study Design and Methods: Two hundred and thirty seven procedures performed on the Amicus (N = 121, Fenwal CS-3000 Plus (N = 50 and Cobe spectra (N = 66 in a one year period were evaluated. The procedures performed on the continuous flow centrifugation (CFC cell separators and donor blood counts (pre and post donation done were included in the study. Results: The percent reduction in hemoglobin (HB, hematocrit (HCT, white blood cell (WBC and platelet count ((PLT ct was 2.9, 3.1, 9, 30.7 (Mean, N = 237 respectively after the procedure. The post donation PLT ct reduced to < 100x109/L (range 80-100 in five donors (N = 5/237, Amicus. The pre donation PLT ct in them was 150-200x109/L. Collection efficiency (percent of Amicus (79.3 was better as compared to the other two machines (CS: 62.5, Cobe: 57.5. PC collected on Cobe spectra had < 1x106 WBC. The donor pre donation PLT levels had a positive correlation to the product PLT yield (r = 0.30, P = 0.000. Conclusion: Monitoring donor blood counts helps to avoid pheresis induced adverse events. A cautious approach is necessary in donors whose pre donation PLT ct is 150-200x109/L. The main variable in PLT yield is donor PLT ct (pre donation. High collection efficiency is a direct measure of an optimally functioning cell separator.

  15. Review and parameterisation of bi-directional ammonia exchange between vegetation and the atmosphere

    Directory of Open Access Journals (Sweden)

    R.-S. Massad

    2010-11-01

    Full Text Available Current deposition schemes used in atmospheric chemical transport models do not generally account for bi-directional exchange of ammonia (NH3. Bi-directional exchange schemes, which have so far been applied at the plot scale, can be included in transport models, but need to be parameterised with appropriate values of the ground layer compensation point (χg, stomatal compensation point (χs and cuticular resistance (Rw. We review existing measurements of χg, χs as well as Rw and compile a comprehensive dataset from which we then propose generalised parameterisations. χs is related to Γs, the non-dimensional ratio of [NH4+]apo and [H+]apo in the apoplast, through the temperature dependence of the combined Henry and dissociation equilibrium. The meta-analysis suggests that the nitrogen (N input is the main driver of the apoplastic and bulk leaf concentrations of ammonium (NH4 apo, NH4 bulk. For managed ecosystems, the main source of N is fertilisation which is reflected in a peak value of χs a few days following application, but also alters seasonal values of NH4 apo and NH4 bulk. We propose a parameterisation for χs which includes peak values as a function of amount and type of fertiliser application which gradually decreases to a background value. The background χs is based on total N input to the ecosystem as a yearly fertiliser application and N deposition (Ndep. For non-managed ecosystems, χs is parameterised based solely on the link with Ndep.

    For Rw we propose a general parameterisation as a function of atmospheric relative humidity (RH, incorporating a minimum value (

  16. Review and parameterisation of bi-directional ammonia exchange between vegetation and the atmosphere

    Directory of Open Access Journals (Sweden)

    R.-S. Massad

    2010-04-01

    Full Text Available Current deposition schemes used in atmospheric chemical transport models do not generally account for bi-directional exchange of ammonia (NH3. Bi-directional exchange schemes, which have so far been applied at the plot scale, can be included in transport models, but need to be parameterised with appropriate values of the stomatal compensation point (χs and cuticular resistance (Rw. We here review existing measurements of χs as well as Rw and compile a comprehensive dataset from which we then propose generalised parameterisations. χs is related to Γs, the non-dimensional ratio of [NH4+]apo and [H+]apo in the apoplast, through the temperature dependence of the combined Henry and solubility equilibrium. The meta-analysis suggests that the nitrogen (N input is the main driver of the apoplastic and bulk leaf concentrations of ammonium (NH+4 apo, NH+4 bulk. For managed ecosystems, the main source of N is fertilisation which is reflected in a peak value of χs a few days following application, but also alters seasonal values of NH+4 apo and NH+4 bulk. We propose a parameterisation for χs which includes peak values as a function of amount and type of fertiliser application which gradually decreases to a background value. The background χs is set based on total N input to the ecosystem as a yearly fertiliser application and N deposition (Ndep. For non-managed ecosystems, χs is parameterised based solely on the link with Ndep.

    For Rw we propose a general parameterisation as a function of atmospheric Relative Humidity (RH, incorporating a minimum value (R w(min, which depends on the ratio of atmospheric acid

  17. Bi-Directional Tuning of Amygdala Sensitivity in Combat Veterans Investigated with fMRI.

    Directory of Open Access Journals (Sweden)

    Tom Brashers-Krug

    Full Text Available Combat stress can be followed by persistent emotional consequences. It is thought that these emotional consequences are caused in part by increased amygdala reactivity. It is also thought that amygdala hyper-reactivity results from decreased inhibition from portions of the anterior cingulate cortex (ACC in which activity is negatively correlated with activity in the amygdala. However, experimental support for these proposals has been inconsistent.We showed movies of combat and civilian scenes during a functional magnetic resonance imaging (fMRI session to 50 veterans of recent combat. We collected skin conductance responses (SCRs as measures of emotional arousal. We examined the relation of blood oxygenation-level dependent (BOLD signal in the amygdala and ACC to symptom measures and to SCRs.Emotional arousal, as measured with SCR, was greater during the combat movie than during the civilian movie and did not depend on symptom severity. As expected, amygdala signal during the less-arousing movie increased with increasing symptom severity. Surprisingly, during the more-arousing movie amygdala signal decreased with increasing symptom severity. These differences led to the unexpected result that amygdala signal in highly symptomatic subjects was lower during the more-arousing movie than during the less-arousing movie. Also unexpectedly, we found no significant inverse correlation between any portions of the amygdala and ACC. Rather, signal throughout more than 80% of the ACC showed a strong positive correlation with signal throughout more than 90% of the amygdala.Amygdala reactivity can be tuned bi-directionally, either up or down, in the same person depending on the stimulus and the degree of post-traumatic symptoms. The exclusively positive correlations in BOLD activity between the amygdala and ACC contrast with findings that have been cited as evidence for inhibitory control of the amygdala by the ACC. The conceptualization of post

  18. Continuous flow measurements using ultrasonic velocity meters - an update

    Science.gov (United States)

    Oltmann, Rick

    1995-01-01

    An article in the summer 1993 Newsletter described USGS work to continously monitor tidal flows in the delta using ultrasonic velocity meters.  This article updates progress since 1993, including new installations, results of data analysis, damage during this year's high flows, and the status of each site.

  19. Comparing contact and immersion freezing from continuous flow diffusion chambers

    Science.gov (United States)

    Nagare, Baban; Marcolli, Claudia; Welti, André; Stetzer, Olaf; Lohmann, Ulrike

    2016-07-01

    Ice nucleating particles (INPs) in the atmosphere are responsible for glaciating cloud droplets between 237 and 273 K. Different mechanisms of heterogeneous ice nucleation can compete under mixed-phase cloud conditions. Contact freezing is considered relevant because higher ice nucleation temperatures than for immersion freezing for the same INPs were observed. It has limitations because its efficiency depends on the number of collisions between cloud droplets and INPs. To date, direct comparisons of contact and immersion freezing with the same INP, for similar residence times and concentrations, are lacking. This study compares immersion and contact freezing efficiencies of three different INPs. The contact freezing data were obtained with the ETH CoLlision Ice Nucleation CHamber (CLINCH) using 80 µm diameter droplets, which can interact with INPs for residence times of 2 and 4 s in the chamber. The contact freezing efficiency was calculated by estimating the number of collisions between droplets and particles. Theoretical formulations of collision efficiencies gave too high freezing efficiencies for all investigated INPs, namely AgI particles with 200 nm electrical mobility diameter, 400 and 800 nm diameter Arizona Test Dust (ATD) and kaolinite particles. Comparison of freezing efficiencies by contact and immersion freezing is therefore limited by the accuracy of collision efficiencies. The concentration of particles was 1000 cm-3 for ATD and kaolinite and 500, 1000, 2000 and 5000 cm-3 for AgI. For concentrations nucleation process that is enhanced compared to immersion freezing due to the position of the INP on the droplet, and we discriminate it from collisional contact freezing, which assumes an enhancement due to the collision of the particle with the droplet. For best comparison with contact freezing results, immersion freezing experiments of the same INPs were performed with the continuous flow diffusion chamber Immersion Mode Cooling chAmber-Zurich Ice

  20. Flow coefficient measurements for an engine cylinder head under transient flow conditions with continuous valve lift change

    Directory of Open Access Journals (Sweden)

    Daesan Oh

    2015-06-01

    Full Text Available A flow coefficient measurement system which is operated under an unsteady intake flow condition in the intake port of a diesel engine cylinder head was developed. In order to determine the actual engine intake flow condition, the valve lift of the intake valve, whose rod is in contact with the camshaft, is varied continuously by rotating the camshaft directly. While varying the rotation speed of the camshaft, the flow coefficients were calculated by measuring various sensor signals, in this case the surge tank pressure, differential pressure in the flow meter, the valve lift when synchronized with the camshaft angle position, and the intake air temperature. The measurement of the flow coefficient was automated using a DAQ board and a computer. The flow coefficients change with the valve lift, and the effects of inertia of the intake flow on the flow coefficients are identified. The mean flow coefficients are obtained by integrating flow coefficients over the camshaft angle position.

  1. Performance assessment of bi-directional knotless tissue-closure devices in juvenile Chinook salmon surgically implanted with acoustic transmitters

    Energy Technology Data Exchange (ETDEWEB)

    Woodley, Christa M.; Wagner, Katie A.; Bryson, Amanda J.; Eppard, Matthew B.

    2013-07-02

    Acoustic transmitters used in survival and telemetry studies are often surgically implanted in fish. While this is a well-established method, it has the potential to affect health, behavior, and survival, thus affecting study results. Much research has been done to try to minimize the harmful effects caused by the transmitter and tagging process. In 2009, we first investigated the use of a bi-directional knotless (barbed) suture material in juvenile Chinook salmon (Oncorhynchus tshawytscha). We found that it resulted in higher tag retention than the simple interrupted suture pattern; however, the occurrence of ulceration and redness increased. The objective of this study was to refine the suturing patterns of the bi-directional knotless suture and retest suture performance in juvenile Chinook salmon. We tested the bi-directional suture using 3 different suture patterns and two needle types: 6-Point (12-mm needle circumference), Wide “N” (12-mm needle circumference), Wide “N” Knot 12 (12-mm needle circumference), and Wide “N” Knot 18 (18-mm needle circumference).

  2. INFORMATION FLOW ASSURED BY IT&C CONTINUITY PLANNING

    OpenAIRE

    Delia Babeanu; Gabriel Cozgarea; Irina Bogdana Pugna; Alexandru Adrian Gavrila

    2009-01-01

    Forwarding the frequent usage of complex processes and the big volume of information, it is imperative to manage the automatic circuit of the document flow in a company activity. The main advantage of such a system consist in document waiting to be proces

  3. Cash flow in the context of economic equation of continuity

    Directory of Open Access Journals (Sweden)

    Fernando Gómez Villarraga

    2006-07-01

    Full Text Available The mathematic scheme, known as economic equation of continuity, is established for the balance of economic resources. In order to apply this equation it is necessary to determine an economic volume of control. The patrimonial equation is also proposed as a speed equationfor this volurne. The integral equation of economic continuity is applied to the «cash» system along with the integral patrimonial equation and so it gets expressions that correspond to model to elaborate cashflow statement with the particularities of the direct and indirect method. This model generales a useful definition for the calculation of this basic financial statement classified by operating, investing and financing activities.

  4. 21 CFR 862.2150 - Continuous flow sequential multiple chemistry analyzer for clinical use.

    Science.gov (United States)

    2010-04-01

    ... analyzer for clinical use. (a) Identification. A continuous flow sequential multiple chemistry analyzer for... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Continuous flow sequential multiple chemistry analyzer for clinical use. 862.2150 Section 862.2150 Food and Drugs FOOD AND DRUG...

  5. 42 CFR 84.148 - Type C supplied-air respirator, continuous flow class; minimum requirements.

    Science.gov (United States)

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Type C supplied-air respirator, continuous flow... RESPIRATORY PROTECTIVE DEVICES Supplied-Air Respirators § 84.148 Type C supplied-air respirator, continuous flow class; minimum requirements. (a) Respirators tested under this section shall be approved only...

  6. PROCESS INTENSIFICATION: MICROWAVE INITIATED REACTIONS USING A CONTINUOUS FLOW REACTOR

    Science.gov (United States)

    The concept of process intensification has been used to develop a continuous narrow channel reactor at Clarkson capable of carrying out reactions under isothermal conditions whilst being exposed to microwave (MW) irradiation thereby providing information on the true effect of mi...

  7. Projecting Ammonia Dry Deposition Using Passive Samplers and a Bi-Directional Exchange Model

    Science.gov (United States)

    Robarge, W. P.; Walker, J. T.; Austin, R. E.

    2011-12-01

    Animal agriculture within the United States is known to be a source of ammonia (NH3) emissions. Dry deposition of NH3 to terrestrial ecosystems immediately surrounding large local sources of NH3 emissions (e.g. animal feeding operations) is difficult to measure, and is best estimated via models. Presented here are results for a semi-empirical modeling approach for estimating air-surface exchange fluxes of NH3 downwind of a large poultry facility (~ 3.5 million layers) using a bi-directional air-surface exchange model. The modeling domain is the western section of the Pocosin Lakes National Wildlife Refuge in Tyrrell, Washington, and Hyde Counties of eastern North Carolina in the South Atlantic Coastal Plain physiographic region. Vegetation within the modeling domain is primarily pocosin wetlands, characterized by acid (pH 3.6) peat soils and a thick canopy of shrub vegetation (leatherwood (Cyrilla racemiflora), inkberry (Ilex glabra), wax myrtle (Morella cerifera)). Land surrounding the refuge is primarily used for crop production: ~ 28%, 24%, and 45% agricultural in Tyrell, Hyde, and Washington counties, respectively. Ammonia air-surface exchange (flux) was calculated using a two-layer canopy compensation point model developed by Nemitz et al. (2001. Quart. J. Roy. Met. Soc. 127, 815 - 833.) as implemented by Walker et al. (2008. Atmos. Environ., 42, 3407 - 3418.), in which the competing processes of emission and deposition within the foliage-soil system were taken into account by relating the net canopy-scale NH3 flux to the net emission potential of the canopy (i.e., foliage and soil). Ammonia air concentrations were measured using ALPHA passive samplers (Center for Ecology and Hydrology, Edinburgh) along transects to the north and northeast of the poultry facility at distances of 800, 2000 and 3200 m, respectively. Samplers were deployed in duplicate at each location at a height of 5.8 m from July 2008 to July 2010 weekly during warm months and bi-weekly curing

  8. Laboratory characterization of a CCD camera system for retrieval of bi-directional reflectance distribution function

    Science.gov (United States)

    Nandy, Prabal; Thome, Kurtis J.; Biggar, Stuart F.

    1999-12-01

    The Remote Sensing Group of the Optical Science Center at the University of Arizona has developed a four-band, multi- spectral, wide-angle, imaging radiometer for the retrieval of the bi-directional reflectance distribution function (BRDF) for vicarious calibration applications. The system consists of a fisheye lens with four interference filters centered at 470 nm, 575 nm, 660 nm, and 835 nm for spectral selection and an astronomical grade 1024 X 1024-pixel, silicon CCD array. Data taken by the system fit in the array as a nominally 0.2 degree per pixel image. This imaging radiometer system has been used in support of the calibration of Landsat-5 and SPOT- satellite sensors. This paper presents the results of laboratory characterization of the system to determine linearity of the detector, point spread function (PSF) and polarization effects. The linearity study was done on detector array without the lens, using a spherical-integrating source with a 1.5-mm aperture. This aperture simulates a point source for distances larger than 60 cm. Data were collected as both a function of exposure time and distance from the source. The results of these measurements indicate that each detector of the array is linear to better than 0.5%. Assuming a quadratic response improves this fit to better than 0.1% over 88% of the upper end of the detector's dynamic range. The point spread function (PSF) of the lens system was measured using the sphere source and aperture with the full camera system operated at a distance of 700 mm from the source, thus the aperture subtends less than the field of view of one pixel. The PSF was measured for several field angles and the signal level was found to fall to less than 1% of the peak signal within 1.5-degrees (10 pixels) for the on-axis case. The effect of this PSF on the retrieval of modeled BRDFs is shown to be less than 0.2% out to view angles of 70 degrees. The final test presented is one to assess the polarization effects of the lens

  9. Ultra-High Voltage 4H-SiC Bi-Directional Insulated Gate Bipolar Transistors

    Science.gov (United States)

    Chowdhury, Sauvik

    4H- Silicon Carbide (4H-SiC) is an attractive material for power semiconductor devices due to its large bandgap, high critical electric field and high thermal conductivity compared to Silicon (Si). For ultra-high voltage applications (BV > 10 kV), 4H-SiC Insulated Gate Bipolar Transistors (IGBTs) are favored over unipolar transistors due to lower conduction losses. With improvements in SiC materials and processing technology, promising results have been demonstrated in the area of conventional unidirectional 4H-SiC IGBTs, with breakdown voltage ratings up to 27 kV. This research presents the experimental demonstration of the world's first high voltage bi-directional power transistors in 4H-SiC. Traditionally, four (two IGBTs and two diodes) or two (two reverse blocking IGBTs) semiconductor devices are necessary to yield a bidirectional switch. With a monolithically integrated bidirectional switch as presented here, the number of semiconductor devices is reduced to only one, which results in increased reliability and reduced cost of the overall system. Additionally, by using the unique dual gate operation of BD-IGBTs, switching losses can be reduced to a small fraction of that in conventional IGBTs, resulting in increased efficiency. First, the performance limits of SiC IGBTs are calculated by using analytical methods. The performance benefits of SiC IGBTs over SiC unipolar devices and Si IGBTs are quantified. Numerical simulations are used to optimize the unit cell and edge termination structures for a 15 kV SiC BD-IGBT. The effect of different device parameters on BD-IGBT static and switching performance are quantified. Second, the process technology necessary for the fabrication of high voltage SiC BD-IGBTs is optimized. The effect of different process steps on parameters such as breakdown voltage, carrier lifetime, gate oxide reliability, SiO2-SiC interface charge density is quantified. A carrier lifetime enhancement process has been optimized for lightly doped

  10. Transitory powder flow dynamics during emptying of a continuous mixer

    OpenAIRE

    Ammarcha, Chawki; Gatumel, Cendrine; Dirion, Jean-Louis; Cabassud, Michel; Mizonov, Vadim; Berthiaux, Henri

    2013-01-01

    International audience This article investigates the emptying process of a continuous powder mixer, from both experimental and modelling points of view. The apparatus used in this work is a pilot scale commercial mixer Gericke GCM500, for which a specific experimental protocol has been developed to determine the hold up in the mixer and the real outflow. We demonstrate that the dynamics of the process is governed by the rotational speed of the stirrer, as it fixes characteristic values of ...

  11. Evaluation of a regional air-quality model with bi-directional NH3 exchange coupled to an agro-ecosystem model

    Directory of Open Access Journals (Sweden)

    J. E. Pleim

    2012-08-01

    Full Text Available Atmospheric ammonia (NH3 is the primary atmospheric base and an important precursor for inorganic particulate matter and when deposited NH3 contributes to surface water eutrophication, soil acidification and decline in species biodiversity. Flux measurements indicate that the air-surface exchange of NH3 is bi-directional. However, the effects of bi-directional exchange, soil biogeochemistry and human activity are not parameterized in air quality models. The US Environmental Protection Agency (EPA's Community Multiscale Air-Quality (CMAQ model with bi-directional NH3 exchange has been coupled with the United States Department of Agriculture (USDA's Environmental Policy Integrated Climate (EPIC agro-ecosystem model's nitrogen geochemistry algorithms. CMAQ with bi-directional NH3 exchange coupled to EPIC connects agricultural cropping management practices to emissions and atmospheric concentrations of reduced nitrogen and models the biogeochemical feedback on NH3 air-surface exchange. This coupled modeling system reduced the biases and error in NHx (NH3 + NH4+ wet deposition and in ambient aerosol concentrations in an annual 2002 Continental US (CONUS domain simulation when compared to a 2002 annual simulation of CMAQ without bi-directional exchange. Fertilizer emissions estimated in CMAQ 5.0 with bi-directional exchange exhibits markedly different seasonal dynamics than the US EPA's National Emissions Inventory (NEI, with lower emissions in the spring and fall and higher emissions in July.

  12. Production of RAFT imprinted smart hydrogel particles in a continuous flow micro-reactor

    OpenAIRE

    Machado, Carla; Freitas, Ana; Kadhirvel, Porkodi; Dias, Rolando; Costa, Mário

    2014-01-01

    Feasibility of the production of RAFT imprinted smart hydrogel particles in continuous flow micro-reactor is here showed. Microfluidic continuous operation was combined with RAFT polymerization and molecular imprinting tecniques involving selected template molecules. New strategies for the production of advanced materials with tailored properties are thus developed. Particles syntetized in the continuous flow micro-reactor (set-up scheme depicted in the graphical abstract) were purified and c...

  13. Transparent organic light-emitting diodes with different bi-directional emission colors using color-conversion capping layers

    International Nuclear Information System (INIS)

    We report a study on transparent organic light-emitting diodes (OLEDs) with different bi-directional emission colors, enabled by color-conversion organic capping layers. Starting from a transparent blue OLED with an uncapped Ag top electrode exhibiting an average transmittance of 33.9%, a 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4H-pyran (DCM)-doped tris-(8-hydroxy-quinolinato)-aluminum (Alq3) capping layer is applied to achieve color-conversion from blue to orange-red on the top side while maintaining almost unchanged device transmittance. This color-conversion capping layer does not only change the color of the top side emission, but also enhances the overall device efficiency due to the optical interaction of the capping layer with the primary blue transparent OLED. Top white emission from the transparent bi-directional OLED exhibits a correlated color temperature around 6000–7000 K, with excellent color stability as evidenced by an extremely small variation in color coordinate of Δ(x,y)=(0.002, 0.002) in the forward luminance range of 100–1000 cd m−2. At the same time, the blue emission color of bottom side is not influenced by the color conversion capping layer, which finally results in different emission colors of the two opposite sides of our transparent OLEDs. - Highlights: • We report transparent organic light-emitting diodes (OLEDs) with different bi-directional emission colors. • Transparent blue OLED with color-conversion organic capping layers (CCL) shows orange top side emission. • Top white emission exhibits a CCT around 7000 K, with excellent color stability on a driving voltage

  14. Effect on the load size on the efficiency of microwave heating under stop flow and continuous flow conditions

    NARCIS (Netherlands)

    Patil, N.G.; Rebrov, E.V.; Esveld, D.C.; Eränen, K.; Benaskar, F.; Meuldijk, Jan; Mikkola, J.P.; Hessel, V.; Hulshof, L.A.; Murzin, D.Y.; Schouten, J.C.

    2012-01-01

    A novel heating efficiency analysis of the microwave heated stop-flow (i.e. stagnant
    liquid) and continuous-flow reactors has been presented. The thermal losses to the surrounding
    air by natural convection have been taken into account for heating efficiency calculation of
    the microwave h

  15. Pattern Switchable Antenna System Using Inkjet-Printed Directional Bow-Tie for Bi-Direction Sensing Applications

    OpenAIRE

    Seung-Hyun Eom; Yunsik Seo; Sungjoon Lim

    2015-01-01

    In this paper, we propose a paper-based pattern switchable antenna system using inkjet-printing technology for bi-direction sensor applications. The proposed antenna system is composed of two directional bow-tie antennas and a switching network. The switching network consists of a single-pole-double-throw (SPDT) switch and a balun element. A double-sided parallel-strip line (DSPSL) is employed to convert the unbalanced microstrip mode to the balanced strip mode. Two directional bow-tie antenn...

  16. A Sustainable, Semi-Continuous Flow Synthesis of Hydantoins.

    Science.gov (United States)

    Vukelić, Stella; Koksch, Beate; Seeberger, Peter H; Gilmore, Kerry

    2016-09-12

    Hydantoins are an important class of heterocycles with applications in pharmacy, agriculture, and as intermediates in organic synthesis. Traditional synthetic procedures to access hydantoins are target oriented with multiple synthetic steps and often use reagents that are not commercially available or sustainable. Herein, an efficient process is described for accessing hydantoins starting from commercially available amines using consecutive gas-liquid transformations (oxygen, carbon dioxide). This semi-continuous process produced ten benzylic/aliphatic hydantoins in good overall yields (52-84 %).

  17. Electroosmotic flow and Joule heating in preparative continuous annular electrochromatography.

    Science.gov (United States)

    Laskowski, René; Bart, Hans-Jörg

    2015-09-01

    An openFOAM "computational fluid dynamic" simulation model was developed for the description of local interaction of hydrodynamics and Joule heating in annular electrochromatography. A local decline of electrical conductivity of the background eluent is caused by an electrokinetic migration of ions resulting in higher Joule heat generation. The model equations consider the Navier-Stokes equation for incompressible fluids, the energy equation for stationary temperature fields, and the mass transfer equation for the electrokinetic flow. The simulations were embedded in commercial ANSYS Fluent software and in open-source environment openFOAM. The annular gap (1 mm width) contained an inorganic C8 reverse-phase monolith as stationary phase prepared by an in situ sol-gel process. The process temperature generated by Joule heating was determined by thermal camera system. The local hydrodynamics in the prototype was detected by a gravimetric contact-free measurement method and experimental and simulated values matched quite well. PMID:25997390

  18. Arsenic incorporation into pyrite at ambient environmental conditions: a continuous-flow experiment

    NARCIS (Netherlands)

    Wolthers, M.; Butler, I.B.; Rickard, D.; Mason, P.R.D.

    2005-01-01

    Pyrite was synthesized in the presence of arsenite, As(III), at concentrations approaching those in ambient environments, under controlled, monitored, anoxic conditions in a continuous-flow reaction system at pH 6 and 25°C. During the continuous pyrite growth in these experiments, a continued uptake

  19. Scalability of Continuous Flow Production of Metal-Organic Frameworks.

    Science.gov (United States)

    Rubio-Martinez, Marta; Hadley, Trevor D; Batten, Michael P; Constanti-Carey, Keri; Barton, Tim; Marley, Dylan; Mönch, Andreas; Lim, Kok-Seng; Hill, Matthew R

    2016-05-10

    Achieving the large-scale production of metal-organic frameworks (MOFs) is crucial for their utilization in applied settings. For many MOFs, quality suffers from large-scale, batch reaction systems. We have developed continuous processes for their production which showed promise owing to their versatility and the high quality of the products. Here, we report the successful upscaling of this concept by more than two orders of magnitude to deliver unprecedented production rates and space-time-yields (STYs) while maintaining the product quality. Encouragingly, no change in the reaction parameters, obtained at small scale, was required. The production of aluminium fumarate was achieved at an STY of 97 159 kg m(-3)  day(-1) and a rate of 5.6 kg h(-1) . PMID:27075923

  20. Deterministic sequential isolation of floating cancer cells under continuous flow.

    Science.gov (United States)

    Tran, Quang D; Kong, Tian Fook; Hu, Dinglong; Marcos; Lam, Raymond H W

    2016-08-01

    Isolation of rare cells, such as circulating tumor cells, has been challenging because of their low abundance and limited timeframes of expressions of relevant cell characteristics. In this work, we devise a novel hydrodynamic mechanism to sequentially trap and isolate floating cells in biosamples. We develop a microfluidic device for the sequential isolation of floating cancer cells through a series of microsieves to obtain up to 100% trapping yield and >95% sequential isolation efficiency. We optimize the trappers' dimensions and locations through both computational and experimental analyses using microbeads and cells. Furthermore, we investigated the functional range of flow rates for effective sequential cell isolation by taking the cell deformability into account. We verify the cell isolation ability using the human breast cancer cell line MDA-MB-231 with perfect agreement with the microbead results. The viability of the isolated cells can be maintained for direct identification of any cell characteristics within the device. We further demonstrate that this device can be applied to isolate the largest particles from a sample containing multiple sizes of particles, revealing its possible applicability in isolation of circulating tumor cells in cancer patients' blood. Our study provides a promising sequential cell isolation strategy with high potential for rapid detection and analysis of general floating cells, including circulating tumor cells and other rare cell types. PMID:27387093

  1. Applications of Continuous-Flow Photochemistry in Organic Synthesis, Material Science, and Water Treatment.

    Science.gov (United States)

    Cambié, Dario; Bottecchia, Cecilia; Straathof, Natan J W; Hessel, Volker; Noël, Timothy

    2016-09-14

    Continuous-flow photochemistry in microreactors receives a lot of attention from researchers in academia and industry as this technology provides reduced reaction times, higher selectivities, straightforward scalability, and the possibility to safely use hazardous intermediates and gaseous reactants. In this review, an up-to-date overview is given of photochemical transformations in continuous-flow reactors, including applications in organic synthesis, material science, and water treatment. In addition, the advantages of continuous-flow photochemistry are pointed out and a thorough comparison with batch processing is presented.

  2. Exploration of pathological prediction of chronic kidney diseases by a novel theory of bi-directional probability

    Science.gov (United States)

    Yang, Yuan; Luo, Min; Xiao, Li; Zhu, Xue-jing; Wang, Chang; Fu, Xiao; Yuan, Shu-guang; Xiao, Fang; Liu, Hong; Dong, Zheng; Liu, Fu-you; Sun, Lin

    2016-01-01

    In the clinic, the pathological types of chronic kidney diseases (CKD) are considered references for choosing treatment protocols. From a statistical viewpoint, a non-invasive method to predict pathological types of CKD is a focus of our work. In the current study, following a frequency analysis of the clinical indices of 588 CKD patients in the department of nephrology, a third-grade class-A hospital, a novel theory is proposed: “bi-directional cumulative probability dichotomy”. Further, two models for the prediction and differential diagnosis of CKD pathological type are established. The former indicates an occurrence probability of the pathological types, and the latter indicates an occurrence of CKD pathological type according to logistic binary regression. To verify the models, data were collected from 135 patients, and the results showed that the highest accuracy rate on membranous nephropathy (MN-100%), followed by IgA nephropathy (IgAN-83.33%) and mild lesion type (MLN-73.53%), whereas lower prediction accuracy was observed for mesangial proliferative glomerulonephritis (0%) and focal segmental sclerosis type (21.74%). The models of bi-directional probability prediction and differential diagnosis indicate a good prediction value in MN, IgAN and MLN and may be considered alternative methods for the pathological discrimination of CKD patients who are unable to undergo renal biopsy. PMID:27557856

  3. The effect of bi-directional loading on fatigue assessment of pressurized piping elbows with local thinned areas

    Energy Technology Data Exchange (ETDEWEB)

    Balan, C. [Department of Mechanical Engineering, Univeristy of Ottawa, Ottawa, Ont., KIN 6N5 (Canada); Redekop, D. [Department of Mechanical Engineering, Univeristy of Ottawa, Ottawa, Ont., KIN 6N5 (Canada)]. E-mail: dredekop@tesla.cc.uottawa.ca

    2005-03-01

    An elastic-plastic finite element study is conducted to determine the effect of bi-directional loading on the fatigue characteristics of pressurized 90 deg. piping elbows with local thinned areas. The analysis is conducted on pressurized piping elbows considered previously in the literature, but analyzed only for in-plane loading. Considering also the out-of-plane loading the present analysis seeks to simulate simultaneous horizontal and vertical seismic actions. A validation study is first conducted in which the present results obtained for in-plane loading are compared with previous results. Comparisons are made for deformation patterns, hoop strain histories, and reaction forces. The relative in-plane to out-of-plane load intensities to be adopted for the combined loading case is determined next. Results considering bi-directional loadings are then found for the pressurized piping elbow for a total of 23 cases of local area thinning. Finally conclusions are drawn about the significance of considering the additional out-of-plane loading.

  4. A high-damping magnetorheological elastomer with bi-directional magnetic-control modulus for potential application in seismology

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Miao, E-mail: yumiao@cqu.edu.cn; Qi, Song; Fu, Jie; Zhu, Mi [Key Lab for Optoelectronic Technology and Systems, Ministry of Education, College of Optoelectronic Engineering, Chongqing University, Chongqing 400044 (China)

    2015-09-14

    A high-damping magnetorheological elastomer (MRE) with bi-directional magnetic-control modulus is developed. This MRE was synthesized by filling NdFeB particles into polyurethane (PU)/ epoxy (EP) interpenetrating network (IPN) structure. The anisotropic samples were prepared in a permanent magnetic field and magnetized in an electromagnetic field of 1 T. Dynamic mechanical responses of the MRE to applied magnetic fields are investigated through magneto-rheometer, and morphology of MREs is observed via scanning electron microscope (SEM). Test result indicates that when the test field orientation is parallel to that of the sample's magnetization, the shear modulus of sample increases. On the other hand, when the orientation is opposite to that of the sample's magnetization, shear modulus decreases. In addition, this PU/EP IPN matrix based MRE has a high-damping property, with high loss factor and can be controlled by applying magnetic field. It is expected that the high damping property and the ability of bi-directional magnetic-control modulus of this MRE offer promising advantages in seismologic application.

  5. Cooperation of electrically stimulated muscle and pneumatic muscle to realize RUPERT bi-directional motion for grasping.

    Science.gov (United States)

    Xikai Tu; Jiping He; Yue Wen; Jian Huang; Xinhan Huang; Hailong Huang; Meng Guo; Yong Yuan

    2014-01-01

    Robot-assisted rehabilitation is an active area of research to meet the demand of repetitive therapy in stroke rehabilitation. Robotic upper-extremity repetitive trainer (RUPERT) with its unidirectional pneumatic muscle actuation (PMA) can be used by most stroke patients that have difficulty moving in one direction because of a weak agonist or hyperactive antagonist. In this research, to broaden the usage of RUPERT, we not only add grasping functionality to the rehabilitation robot with the help of surface Functional Electrical Stimulation (FES) but also realize the robot joint bi-directional motion by using a PMA in cooperation with surface FES evoked paralyzed muscle force. This integrative rehabilitation strategy is explored for training patients to practice coordinated reaching and grasping functions. The effectiveness of this FES electrically evoked bio-actuator way is verified through a method that separates the mixed electromyogram (MEMG) into the electrically evoked electromyogram (EEMG) and voluntary electromyogram (VEMG). This is a promising approach to alleviate the size and mechanical complexity of the robot, thereby the cost of the joint bi-directional actuator rehabilitation robot by means of their own characteristics of stroke subjects.

  6. X-rays from protostellar jets: emission from continuous flows

    Science.gov (United States)

    Bonito, R.; Orlando, S.; Peres, G.; Favata, F.; Rosner, R.

    2007-02-01

    Context: Recently X-ray emission from protostellar jets has been detected with both XMM-Newton and Chandra satellites, but the physical mechanism which can give rise to this emission is still unclear. Aims: We performed an extensive exploration of the parameter space for the main parameters influencing the jet/ambient medium interaction. Aims include: 1) to constrain the jet/ambient medium interaction regimes leading to the X-ray emission observed in Herbig-Haro objects in terms of the emission by a shock forming at the interaction front between a continuous supersonic jet and the surrounding medium; 2) to derive detailed predictions to be compared with optical and X-ray observations of protostellar jets; 3) to get insight into the protostellar jet's physical conditions. Methods: We performed a set of two-dimensional hydrodynamic numerical simulations, in cylindrical coordinates, modeling supersonic jets ramming into a uniform ambient medium. The model takes into account the most relevant physical effects, namely thermal conduction and radiative losses. Results: Our model explains the observed X-ray emission from protostellar jets in a natural way. In particular, we find that a protostellar jet that is less dense than the ambient medium well reproduces the observations of the nearest Herbig-Haro object, HH 154, and allows us to make detailed predictions of a possible X-ray source proper motion (v_sh ≈500 km s-1) detectable with Chandra. Furthermore, our results suggest that the simulated protostellar jets which best reproduce the X-rays observations cannot drive molecular outflows.

  7. Continuous Flow Nucleophilic Aromatic Substitution with Dimethylamine Generated in Situ by Decomposition of DMF

    DEFF Research Database (Denmark)

    Petersen, Trine P; Larsen, Anders Foller; Ritzén, Andreas;

    2013-01-01

    A safe, practical, and scalable continuous flow protocol for the in situ generation of dimethylamine from DMF followed by nucleophilic aromatic substitution of a broad range of aromatic and heteroaromatic halides is reported....

  8. Kinetic characteristics of continuous flow polymerase chain reaction chip: A numerical investigation

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Continuous flow PCR (polymerase chain reaction) chip holds impressive advantages compared to micro chamber PCR chip. In order to have better understanding of kinetic characteristics of continuous flow PCR chip, a comprehensive mathematical model is presented in this paper, including melting, annealing and extension phases of a typical PCR process which has the essence of a convection-diffusion-reaction system. Using this model, we can simulate the PCR process in series of reaction cycles. Numerical results show that the average sample velocity plays a significant role in affecting the amplification efficiency. Also, appropriate combination of the PCR mixture is important for high-quality DNA amplification. Giving a large initial DNA concentration range, the continuous flow PCR scheme holds excellent real-time detection ability theoretically. The present numerical model bridges the temperature distribution to the real DNA amplification, and thereby is able to successfully predict continuous flow PCR properties which are important for the chip design.

  9. Continuous gas/liquid–liquid/liquid flow synthesis of 4-fluoropyrazole derivatives by selective direct fluorination

    Directory of Open Access Journals (Sweden)

    Jessica R. Breen

    2011-08-01

    Full Text Available 4-Fluoropyrazole systems may be prepared by a single, sequential telescoped two-step continuous gas/liquid–liquid/liquid flow process from diketone, fluorine gas and hydrazine starting materials.

  10. Best Practices for Continuous Monitoring of Temperature and Flow in Wadeable Streams (Final Report)

    Science.gov (United States)

    This final report is a technical "best practices" document describing sensor deployment for and collection of continuous temperature and flow data at ungaged sites in wadeable streams. This document addresses questions related to equipment needs; configuration, placement, and ins...

  11. Continuous vs. pulsating flow boiling. Part 2: Statistical comparison using response surface methodology

    DEFF Research Database (Denmark)

    Kærn, Martin Ryhl; Elmegaard, Brian; Meyer, Knud Erik;

    2016-01-01

    -motor expansion valve. Two experimental designs (data point sets) are generated using a modified Central Composite Design for each valve and their response surfaces are compared using the quadratic model. Statistical information on the significant model terms are used to clarify whether the effect of fluid flow......Response surface methodology is used to investigate an active method for flow boiling heat transfer enhancement by means of fluid flow pulsation. The flow pulsations are introduced by a flow modulating expansion device and compared with the baseline continuous flow provided by a stepper...... pulsations is statistically significant in terms of the time-averaged flow boiling heat transfer coefficient. The cycle time range from 1 s to 9 s for the pulsations. The results show that the effect of fluid flow pulsations is statistically significant, disregarding the lowest heat flux measurements...

  12. PRELIMINARY DESIGN OF OSCILLATORY FLOW BIODIESEL REACTOR FOR CONTINUOUS BIODIESEL PRODUCTION FROM JATROPHA TRIGLYCERIDES

    OpenAIRE

    AZHARI T. I. MOHD. GHAZI; M. F. M. GUNAM RESUL; R. YUNUS; T. C. SHEAN YAW

    2008-01-01

    The concept of a continuous process in producing biodiesel from jatropha oil by using an Oscillatory Flow Biodiesel Reactor (OFBR) is discussed in this paper. It has been recognized that the batch stirred reactor is a primary mode used in the synthesis of biodiesel. However, pulsatile flow has been extensively researcehed and the fundamental principles have been successfully developed upon which its hydrodynamics are based. Oscillatory flow biodiesel reactor offers precise control of mixing b...

  13. FEATURES OF LONG-TERM MECHANICAL CIRCULATORY SUPPORT WITH CONTINUOUS-FLOW PUMP

    Directory of Open Access Journals (Sweden)

    G. P. Itkin

    2012-01-01

    Full Text Available In a review of the comparative analysis of methods and tools for long-term mechanical circulatory support with continuous flow and pulsatile flow implantable pumps. Particular attention is paid to the choice of the optimal modes of the operation of pumps based on the physical principles of the interaction between a the steady flow of blood to the pulsatile mechanics of the heart chambers. 

  14. Continuous vs. pulsating flow boiling. Part 1: Experimental comparison and visualization

    DEFF Research Database (Denmark)

    Kærn, Martin Ryhl; Elmegaard, Brian; Meyer, Knud Erik;

    2016-01-01

    . The fluid pulsations are introduced by a flow modulating expansion device and are compared with continuous flow by a stepper-motor expansion valve in terms of time-averaged heat transfer coefficient. The cycle time ranges from 1 s to 9 s for the pulsations. The time-averaged heat transfer coefficients...... transfer coefficient by as much as 8 % at high heat flux (q ≥ 35 kW/m2) and cycle time (8 s). The latter reduction is adhered to the significant dry-out when the flow modulating expansion valve is closed.......This experimental study investigates an active method for flow boiling heat transfer enhancement by means of fluid flow pulsation. The hypothesis is that pulsations increase the flow boiling heat transfer by means of better bulk fluid mixing, increased wall wetting and flow-regime destabilization...

  15. Longitudinal foliation rigidity and Lipschitz-continuous invariant forms for hyperbolic flows

    CERN Document Server

    Foulon, Patrick

    2010-01-01

    In several contexts the defining invariant structures of a hyperbolic dynamical system are smooth only in systems of algebraic origin (smooth rigidity), and we prove new results of this type for a class of flows. For a compact Riemannian manifold and a uniformly quasiconformal transversely symplectic Anosov flow we define the longitudinal KAM-cocycle and use it to prove a rigidity result: The joint stable/unstable subbundle is Zygmund-regular, and higher regularity implies vanishing of the longitudinal KAM-cocycle, which in turn implies that the subbundle is Lipschitz-continuous and indeed that the flow is smoothly conjugate to an algebraic one. To establish the latter, we prove results for algebraic Anosov systems that imply smoothness and a special structure for any Lipschitz-continuous invariant 1-form. Several features of the reasoning are interesting: The use of exterior calculus for Lipschitz-continuous forms, that the arguments for geodesic flows and infranilmanifoldautomorphisms are quite different, a...

  16. Bi-directional controlled release of ibuprofen and Mg(2+) from magnesium alloys coated by multifunctional composite.

    Science.gov (United States)

    Dong, Hongzhou; Li, Qing; Tan, Cui; Bai, Ningning; Cai, Peng

    2016-11-01

    Two major problems for magnesium alloy implant are the high degradation rate and easy infection associated with implantation. Herein, a surface drug delivery system (Mg/Epoxy resin-ZnO/PCL-Ibuprofen) which can realize bi-directional controlled release of ibuprofen and Mg(2+) was designed via a dip coating process followed by spraying. The in vitro test demonstrated that the ibuprofen in drug-eluting compound material showed sustained release profiles for 22days, which can effectively solve the local cellular rejection and inflammation during the early stage of implantation. Besides, the drug carrier also exhibited improved corrosion resistance duel to the high combining strength between Epoxy resin-ZnO coating and magnesium alloy, so Mg(2+) can release slowly at first and then speeded up later. This approach may be suitable for coating other implant materials such as stainless steel, titanium alloy etc. PMID:27524048

  17. Parallel input parallel output high voltage bi-directional converters for driving dielectric electro active polymer actuators

    DEFF Research Database (Denmark)

    Thummala, Prasanth; Zhang, Zhe; Andersen, Michael A. E.;

    2014-01-01

    is to design and implement driving circuits for the DEAP actuators for their use in various applications. This paper presents implementation of parallel input, parallel output, high voltage (~2.5 kV) bi-directional DC-DC converters for driving the DEAP actuators. The topology is a bidirectional flyback DC......-DC converter incorporating commercially available high voltage MOSFETs (4 kV) and high voltage diodes (5 kV). Although the average current of the aforementioned devices is limited to 300 mA and 150 mA, respectively, connecting the outputs of multiple converters in parallel can provide a scalable design....... This enables operating the DEAP actuators in various static and dynamic applications e.g. positioning, vibration generation or damping, and pumps. The proposed idea is experimentally verified by connecting three high voltage converters in parallel to operate a single DEAP actuator. The experimental results...

  18. Bi-directional terahertz-to-infrared emission from metal-coated nanostructures upon femtosecond laser irradiation.

    Science.gov (United States)

    Zhang, Liangliang; Wu, Tong; Zhao, Ji; Zhang, Cunlin; Zhang, X-C

    2015-09-21

    We report on the investigation of bi-directional terahertz-to-infrared (THz-to-IR) radiation from a metal film coated on a substrate with randomly ordered pore arrays by irradiation of femtosecond laser pulses. THz-to-IR radiation was observed both for front-side excitation (laser incident on the metal surface) and for rear-side excitation (laser incident on the substrate). In both cases, the radiation was observed both in the propagation direction of the laser beam and in the reverse direction. Considering these findings, we propose a thermal emission mechanism based on the production of surface plasmons, either delocalized (through phase-matched excitation) or localized (through surface roughness) at the air/metal and metal/substrate interfaces. PMID:26406717

  19. Pattern Switchable Antenna System Using Inkjet-Printed Directional Bow-Tie for Bi-Direction Sensing Applications.

    Science.gov (United States)

    Eom, Seung-Hyun; Seo, Yunsik; Lim, Sungjoon

    2015-01-01

    In this paper, we propose a paper-based pattern switchable antenna system using inkjet-printing technology for bi-direction sensor applications. The proposed antenna system is composed of two directional bow-tie antennas and a switching network. The switching network consists of a single-pole-double-throw (SPDT) switch and a balun element. A double-sided parallel-strip line (DSPSL) is employed to convert the unbalanced microstrip mode to the balanced strip mode. Two directional bow-tie antennas have different radiation patterns because of the different orientation of the reflectors and antennas. It is demonstrated from electromagnetic (EM) simulation and measurement that the radiation patterns of the proposed antenna are successfully switched by the SPDT switch. PMID:26690443

  20. Pattern Switchable Antenna System Using Inkjet-Printed Directional Bow-Tie for Bi-Direction Sensing Applications

    Directory of Open Access Journals (Sweden)

    Seung-Hyun Eom

    2015-12-01

    Full Text Available In this paper, we propose a paper-based pattern switchable antenna system using inkjet-printing technology for bi-direction sensor applications. The proposed antenna system is composed of two directional bow-tie antennas and a switching network. The switching network consists of a single-pole-double-throw (SPDT switch and a balun element. A double-sided parallel-strip line (DSPSL is employed to convert the unbalanced microstrip mode to the balanced strip mode. Two directional bow-tie antennas have different radiation patterns because of the different orientation of the reflectors and antennas. It is demonstrated from electromagnetic (EM simulation and measurement that the radiation patterns of the proposed antenna are successfully switched by the SPDT switch.

  1. Activation and Inhibition of Posterior Parietal Cortex Have Bi-Directional Effects on Spatial Errors Following Interruptions

    Directory of Open Access Journals (Sweden)

    Cyrus Khan Foroughi

    2015-01-01

    Full Text Available Interruptions to ongoing mental activities are omnipresent in our modern digital world, but the brain networks involved in interrupted performance are not known, nor have the activation of those networks been modulated. Errors following interruptions reflect failures in spatial memory, whose maintenance is supported by a brain network including the right posterior parietal cortex (PPC. The present study therefore used bi-directional transcranial Direct Current Stimulation (tDCS of right PPC to examine the neuromodulation of spatial errors following interruptions, as well as performance on another PPC-dependent task, mental rotation. Anodal stimulation significantly reduced the number of interruption-based errors and increased mental rotation accuracy whereas cathodal stimulation significantly increased errors and reduced mental rotation accuracy. The results provide evidence for a causal role of the PPC in the maintenance of spatial representations during interrupted task performance.

  2. Improvised Security for RDF using Random Salt and Levels with Bi-Directional Translation to Relational Database

    Directory of Open Access Journals (Sweden)

    Siva Srinivasa Rao Mothukuri

    2013-12-01

    Full Text Available A Middleware Framework is required for SemanticWeb applications to access data from relational databases andlegacy storage systems, without replication or synchronization.Resource Description Framework is one such type ofmiddleware framework which bridges the gap between twoneeds. Though, there were some efforts to publish relationaldata as Resource Description Framework triples, they presentthe existing data into respective RDF stack only in Read-onlymanner, also in dearth of security. This paper accomplishes suchin vulnerabilities by enhancing a nexus to be bi-directional,allowing data updates specified as triples to be sent back to therelational database as tuples. The data can beUpdated/Inserted/Deleted wherever required. Also, this paperdeals with the Level-1 and Level-2 security hierarchy. In thosetwo levels, a random “salt” is added up to the data followed byencryption.

  3. 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.

  4. Mathematical Model of Fluid Flow and Solidification in Mold Region of Continuous Slab Casting

    Institute of Scientific and Technical Information of China (English)

    谭利坚; 沈厚发; 柳百成

    2003-01-01

    To simulate the phenomena in the mold region of continuous casting by coupling fluid flow and solidification, a three-dimensional mathematical model has been developedbased on the K-ε turbulence equations and the SIMPLER algorithm. A pseudo source term was introduced into the energy equation to account for the latent heat and kinetic energy. The fluid flow in the mushy zone was calculated by defining the fluid viscosity as a function of the solid fraction in the mushy zone. Fine meshes in the solid region improve convergence and reduce iteration time. Comparison of the fluid flow and temperature distribution with and without solidification shows that although the solid shell in the mold is thin, it still greatly affects the flow pattern. The numerical results obtained provide details of the fluid flow and solidification phenomena which can be used to optimize the nozzle structure and other process parameters in continuous casting.

  5. Simulation for the development of the continuous groundwater flow measurement technology

    Science.gov (United States)

    Kobayashi, Kaoru; Kumagai, Koki; Fujima, Ritsuko; Chikahisa, Hiroshi

    The flow of groundwater varies with time due to rainfall, atmospheric pressure change, tidal change, melting of snow during seasonal change, underground construction works etc. Therefore, to increase the precision of assessing in-situ groundwater flow characteristics, it is important to measure continuously the direction and velocity of the flow, in addition to obtaining accurate data for the afore mentioned environmental changes. The first part of this paper describes the development of a new device for measuring the direction and velocity of groundwater flow. The device was composed of a unique floating sensor with a hinge end at the bottom, which enabled continuous measurement of groundwater flow based on image data processing technique. In the second part, discussion is focused on clarifying the optimum cross-section shape and the behavior of the float sensor in saltwater and freshwater using numerical analysis.

  6. Bi-Directional Fluorescence Distribution and its Correction for Estimates of Gross Ecosystem Productivity and Photosynthetic Light-Use Efficiency

    Science.gov (United States)

    Liu, Liangyun; Liu, Xinjie

    2015-04-01

    Passive measurement of solar-induced chlorophyll fluorescence (SIF) presents a new way for directly estimating the photosynthetic activities. In this study, one diurnal multi-angular spectral experiment and three independent diurnal flux experiments were carried out on winter wheat and maize to assess directional emission of SIF for estimating photosynthesis activities. Firstly, the Bi-Directional Fluorescence Distribution Function (BFDF) of SIF was investigated. A BFDF shape similar to the red Bi-Directional Reflectance Distribution Function (BRDF) was observed for the directional SIF emissions at 688 nm. Secondly, the relationship between the directional emission of canopy SIF and BRDF reflectance was examined, finding a strict linear correlation between SIF and reflectance at 688 nm, with an R2> 0.80 for all seven BRDF observations on winter wheat. Then, a BFDF correction model for the canopy SIF at 688 nm was presented by dividing by the canopy reflectance, and about 65.3% of the directional variation was successfully removed. Finally, the BFDF-corrected SIF signals were linked to photosynthetic activities, including gross ecosystem productivity (GEP) and photosynthetic light-use efficiency (LUE), and the determination coefficients between photosynthetic activities and the BFDF-corrected SIF increased for most cases. For GEP, the determination coefficients were slightly improved from 0.563, 0.382, and 0.613 (for raw SIF signals) to 0.592, 0.473, and 0.640 for all three diurnal experiments. For LUE, the determination coefficients increased from 0.393, and 0.358 to 0.517, and 0.528 for two experiments, while deceased slightly from 0.695 to 0.607 for one experiment. Therefore, according to the above preliminary results, the canopy SIF cannot be regarded as isotropic, and the directional emission SIF may be an important uncertainty in estimates of GEP and LUE.

  7. A Bi-directional Energy Splitable Model for Energy Optimization in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    A. Rajeswari

    2011-01-01

    Full Text Available Wireless Sensor Networks is a budding  prototype of networking and computing, where a node may be self powered and individual node have the capability to sense and compute and communicate. Wireless Sensor Networks have been proposed for variety of applications such as Industrial control and monitoring and home automation and consumer electronics and security andMilitary sensing, Asset tracking and supply chain management, Intelligent Agriculture, Missile directing, Fire alarming, Landslide Warning, Environmental monitoring and health monitoring and commercial applications. In Wireless Sensor Network large number of nodes are deployed randomly. Depends on the network architecture the application may be personalized such as Energy Efficiency, Routing and Power Management and data dissemination. Energy Optimization involves in minimizing an energy expenditure and maximizing the lifetime of the complete network. In the proposed work, the placement of nodes are directly involved with residual energy. Energy Optimization in sensor network is very difficult task to achieve it. The optimization of energy is performed through Bidirectional Energy Splitable Model. The data flow in both forward and backward directions are considered, In order to achieve the best QOS in transmission, some parameters such as load, delay and direction of individual nodes are considered. A mathematical model is developed to determine the data flow of  individual node based on the residual energy.

  8. Flow angle dependent photoacoustic Doppler power spectra under intensity-modulated continuous wave laser excitation

    Directory of Open Access Journals (Sweden)

    Yu Tong

    2016-02-01

    Full Text Available Photoacoustic Doppler (PAD power spectra showing an evident Doppler shift represent the major characteristics of the continuous wave-excited or burst wave-excited versions of PAD flow measurements. In this paper, the flow angle dependences of the PAD power spectra are investigated using an experiment setup that was established based on intensity-modulated continuous wave laser excitation. The setup has an overall configuration that is similar to a previously reported configuration, but is more sophisticated in that it accurately aligns the laser illumination with the ultrasound detection process, and in that it picks up the correct sample position. In the analysis of the power spectra data, we find that the background power spectra can be extracted by combining the output signals from the two channels of the lock-in amplifier, which is very useful for identification of the PAD power spectra. The power spectra are presented and analyzed in opposite flow directions, at different flow speeds, and at different flow angles. The power spectra at a 90° flow angle show the unique properties of symmetrical shapes due to PAD broadening. For the other flow angles, the smoothed power spectra clearly show a flow angle cosine relationship.

  9. Weak Continuity of the Flow Maps for Some Classical Nonlinear Dispersive Equations on the Line

    CERN Document Server

    Cui, Shangbin

    2009-01-01

    In this paper we establish the weak continuity of the flow maps for some classical one-dimensional nonlinear dispersive equations on the line. These equations include: the cubic nonlinear Schrodinger equation, the Benjamin-Ono equation and the modified Benjamin-Ono equation. By using the "local-smoothing" estimates combined with suitable uniqueness results, we prove that the flow maps for cubic NLS in L^2(R), for Benjamin-Ono in L^2(R) and for modified Benjamin-Ono in H^{1/2}(R) are all weakly continuous. The spaces considered here are borderline Sobolev spaces for the corresponding equations from the point view of the local well-posedness theory. Meanwhile, recently it has been proved that, in the periodic case, the flow maps in L^2(T) of the cubic NLS and the Benjamin-Ono equation are not weakly continuous.

  10. Continuation in a parameter - Experience with viscous and free surface flows

    Science.gov (United States)

    Kheshgi, H. S.; Basaran, O. A.; Benner, R. E.; Kistler, S. F.; Scriven, L. E.

    1983-01-01

    The results of modifications in continuation methods applied to obtain solutions to the Navier-Stokes systems of equations for incompressible, two-dimensional, steady flows are reported. It is shown that parameter continuation permits prediction of accurate, initial estimates for iterative processing of nonlinear finite difference and finite element equations of motions. The new parameter steps are derived from values of the preceding parameter steps. The accuracy of the estimates is ensured with appropriate choices of the step size. The continuation predictor/iterative corrector is demonstrated to trace the branches of parameter space along which steady flow states are found, and techniques are available for tracing multiply branching paths. The techniques are applied to solving the Navier-Stokes equations for flow through a rotating square channel, the formation of a falling liquid curtain, and gyrostatic equilibria of rotating cylindrical drops.

  11. Performance estimation of bi-directional turbines in wave energy plants

    Institute of Scientific and Technical Information of China (English)

    S. Anand; V. Jayashankar; S. Nagata; K. Toyota; M.Takao; T. Setoguchi

    2007-01-01

    Oscillating water column (OWC) based wave energy plants have been designed with several types of bidirectional turbines for converting pneumatic power to shaft power. Impulse turbines with linked guide vanes and fixed guide vanes have been tested at the Indian Wave Energy plant. This was after initial experimentation with Well's turbines. In contrast to the Well's turbine which has a linear damping characteristic, impulse turbines have non-linear damping. This has an important effect in the overall energy conversion from wave to wire. Optimizing the wave energy plant requires a turbine with linear damping and good efficiency over a broad range of flow coefficient. This work describes how such a design can be made using fixed guide vane impulse turbines. The Indian Wave Energy plant is used as a case study.

  12. Progress on the Design and Development of the Continuous-Flow Total Artificial Heart

    OpenAIRE

    Kobayashi, Mariko; Horvath, David J.; Mielke, Nicole; Shiose, Akira; Kuban, Barry; Goodin, Mark; Fukamachi, Kiyotaka; Golding, Leonard A.R.

    2012-01-01

    Cleveland Clinic’s continuous-flow total artificial heart has one motor and one rotating assembly supported by a hydrodynamic bearing. The right hydraulic output is self regulated by passive axial movement of the rotating assembly to balance itself with the left output. The purpose of this article is to present progress in four areas of development: the automatic speed control system, self-regulation to balance right/left inlet pressures and flows, hemolysis testing using calf blood, and coup...

  13. Hyperemic flow heterogeneity within the calf, foot, and forearm measured with continuous arterial spin labeling MRI

    OpenAIRE

    Wu, Wen-Chau; Wang, Jiongjiong; Detre, John A.; Wehrli, Felix W.; Mohler, Emile; Ratcliffe, Sarah J.; Floyd, Thomas F

    2008-01-01

    Arterial spin labeling (ASL) is a noninvasive magnetic resonance imaging (MRI) technique for microvascular blood flow measurement. We used a continuous ASL scheme (CASL) to investigate the hyperemic flow difference between major muscle groups in human extremities. Twenty-four healthy subjects with no evidence of vascular disease were recruited. MRI was conducted on a 3.0 Tesla Siemens Trio whole body system with a transmit/receive knee coil. A nonmagnetic orthopedic tourniquet system was used...

  14. Mean Field Theory of Sandpile Avalanches: from the Intermittent to the Continuous Flow Regime

    OpenAIRE

    Benza, V. G.; Nori, Franco; Pla, Oscar

    1993-01-01

    We model the dynamics of avalanches in granular assemblies in partly filled rotating cylinders using a mean-field approach. We show that, upon varying the cylinder angular velocity $\\omega$, the system undergoes a hysteresis cycle between an intermittent and a continuous flow regimes. In the intermittent flow regime, and approaching the transition, the avalanche duration exhibits critical slowing down with a temporal power-law divergence. Upon adding a white noise term, and close to the trans...

  15. Residence times and mixing of a novel continuous oscillatory flow screening reactor

    OpenAIRE

    Reis, N.; A.A. Vicente; Teixeira, J. A.; Mackley, M.R.

    2004-01-01

    This paper is concernedwith the fluidmechanics andmixing performance of a novel oscillatory flow screening reactor. Using fibre optic probes, a mixing coefficient k_m is determinedfor the system as a function of the applied fluid oscillation frequency and amplitud. In a continuous operation mean residence time and a backmixing coefficient g are estimatedas a function of the oscillation conditions. Finally, in order to compare data with numerical simulations steady state flow data are...

  16. Epidural blood flow and regression of sensory analgesia during continuous postoperative epidural infusion of bupivacaine

    DEFF Research Database (Denmark)

    Mogensen, T; Højgaard, L; Scott, N B;

    1988-01-01

    Epidural blood flow was measured in seven patients undergoing elective abdominal surgery during combined lumbar epidural and general anesthesia. After an initial dose of 20 ml plain bupivacaine 0.5%, a continuous epidural infusion of bupivacaine 0.5% (8 ml/hr) was given for 16 hours for postopera......Epidural blood flow was measured in seven patients undergoing elective abdominal surgery during combined lumbar epidural and general anesthesia. After an initial dose of 20 ml plain bupivacaine 0.5%, a continuous epidural infusion of bupivacaine 0.5% (8 ml/hr) was given for 16 hours...... surgery, and 8, 12, and 16 hours later during the continuous infusion. Initial blood flow was 6.0 +/- 0.7 ml/min per 100 g tissue (mean +/- SEM). After epidural bupivacaine, blood flow increased in all seven patients to 7.4 +/- 0.7 ml (P less than 0.02). Initial level of sensory analgesia was T4.5 +/- 0...... than 0.03) in the other five patients as the level of sensory analgesia regressed postoperatively. These data suggest that changes in epidural blood flow during continuous epidural infusion of bupivacaine, and thus changes in rates of vascular absorption of bupivacaine from the epidural space, may...

  17. An efficient continuous flow process for the synthesis of a non-conventional mixture of fructooligosaccharides.

    Science.gov (United States)

    Zambelli, Paolo; Tamborini, Lucia; Cazzamalli, Samuele; Pinto, Andrea; Arioli, Stefania; Balzaretti, Silvia; Plou, Francisco J; Fernandez-Arrojo, Lucia; Molinari, Francesco; Conti, Paola; Romano, Diego

    2016-01-01

    A sustainable and scalable process for the production of a new mixture of fructooligosaccharides (FOS) was developed using a continuous-flow approach based on an immobilized whole cells-packed bed reactor. The technological transfer from a classical batch system to an innovative flow environment allowed a significant improvement of the productivity. Moreover, the stability of this production system was ascertained by up to 7 days of continuous working. These results suggest the suitability of the proposed method for a large-scale production of the desired FOS mixture, in view of a foreseeable use as a novel prebiotic preparation. PMID:26213017

  18. Continuous-Flow Processes in Heterogeneously Catalyzed Transformations of Biomass Derivatives into Fuels and Chemicals

    Directory of Open Access Journals (Sweden)

    Antonio A. Romero

    2012-07-01

    Full Text Available Continuous flow chemical processes offer several advantages as compared to batch chemistries. These are particularly relevant in the case of heterogeneously catalyzed transformations of biomass-derived platform molecules into valuable chemicals and fuels. This work is aimed to provide an overview of key continuous flow processes developed to date dealing with a series of transformations of platform chemicals including alcohols, furanics, organic acids and polyols using a wide range of heterogeneous catalysts based on supported metals, solid acids and bifunctional (metal + acidic materials.

  19. Continuous-flow organic synthesis: a tool for the modern medicinal chemist.

    Science.gov (United States)

    Wiles, Charlotte; Watts, Paul

    2009-12-01

    Medicinal chemists are under increasing pressure, not only to identify lead compounds and optimize them into clinical candidates, but also to produce materials in sufficient quantities for subsequent investigation. With this in mind, continuous-flow methodology presents an opportunity to reduce the time taken to, first, identify the compound and, second, scale the process for evaluation and, where necessary, production. It is therefore the aim of this review to provide the reader with an insight into the advantages associated with the use of continuous-flow chemistry through the use of strategically selected literature examples. PMID:21425981

  20. Titer-plate formatted continuous flow thermal reactors: Design and performance of a nanoliter reactor

    OpenAIRE

    Chen, Pin-Chuan; Park, Daniel S.; You, Byoung-Hee; Kim, Namwon; Park, Taehyun; Steven A Soper; Nikitopoulos, Dimitris E.; Murphy, Michael C.

    2010-01-01

    Arrays of continuous flow thermal reactors were designed, configured, and fabricated in a 96-device (12 × 8) titer-plate format with overall dimensions of 120 mm × 96 mm, with each reactor confined to a 8 mm × 8 mm footprint. To demonstrate the potential, individual 20-cycle (740 nL) and 25-cycle (990 nL) reactors were used to perform the continuous flow polymerase chain reaction (CFPCR) for amplification of DNA fragments of different lengths. Since thermal isolation of the required temperatu...

  1. Continuous-flow stereoselective organocatalyzed Diels-Alder reactions in a chiral catalytic "homemade" HPLC column.

    Science.gov (United States)

    Chiroli, Valerio; Benaglia, Maurizio; Cozzi, Franco; Puglisi, Alessandra; Annunziata, Rita; Celentano, Giuseppe

    2013-07-19

    Continuous-flow organocatalyzed Diels-Alder reactions have been performed with excellent enantioselectivity for the first time in a chiral "homemade" HPLC column, packed with silica on which a MacMillan catalyst has been supported by a straightforward immobilization procedure. The versatility of the system was also proven by running with the same column continuous-flow stereoselective reactions with three different substrates, showing that the catalytic reactor may efficiently work in continuo for more than 150 h; the regeneration of the HPLC column was also demonstrated, allowing to further extend the activity of the reactor to more than 300 operating hours. PMID:23808663

  2. LATTICE BGK MODEL SIMULATION OF ASYMMETRIC FLOW INSIDE A CONTINUOUS SLAB CASTING MOLD

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao-jun; SHEN Hou-fa

    2006-01-01

    The incompressible lattice Bhatnager-Gross-Krook (BGK) model of computational fluid dynamics, from which the unsteady incompressible Navier-Stokes equations can be exactly derived with the limit of small Mach number, was established in continuous casting mold. An asymmetric flow pattern in the two-dimensional central plane of continuous slab casting mold was simulated, and the flow pattern is not stationary but changes over frequently if the Reynolds number is larger than 3000 or so. The results are found to be in excellent agreement with previous experimental results.

  3. Study of an ammonia-based wet scrubbing process in a continuous flow system

    Energy Technology Data Exchange (ETDEWEB)

    Mao, James X.; Lee, Anita S.; Kitchin, John R.; Nulwala, Hunaid B.; Luebke, David R.; Damodaran, Krishnan

    2013-01-01

    A continuous gas and liquid flow, regenerative scrubbing process for CO{sub 2} capture was demonstrated at the bench-scale level. An aqueous ammonia-based solution captures CO{sub 2} from simulated flue gas in an absorber and releases a nearly pure stream of CO{sub 2} in the regenerator. After the regeneration, the solution of ammonium compounds is recycled to the absorber. The design of a continuous flow unit was based on earlier exploratory results from a semi-batch reactor, where a CO{sub 2} and N{sub 2} simulated flue gas mixture flowed through a well-mixed batch of ammonia-based solution. During the semi-batch tests, the solution was cycled between absorption and regeneration steps to measure the carrying capacity of the solution at various initial ammonia concentrations and temperatures. Consequentially, a series of tests were conducted on the continuous unit to observe the effect of various parameters on CO{sub 2} removal efficiency and regenerator effectiveness within the flow system. The parameters that were studied included absorber temperature, regenerator temperature, initial NH{sub 3} concentration, simulated flue gas flow rate, liquid solvent inventory in the flow system, and height of the packed-bed absorber. From this testing and subsequent testing, ammonia losses from both the absorption and regeneration steps were quantified, and attempts were made to maintain steady state during operations. Implications of experimental results with respect to process design are discussed.

  4. Multistep continuous-flow synthesis of (R)- and (S)-rolipram using heterogeneous catalysts

    Science.gov (United States)

    Tsubogo, Tetsu; Oyamada, Hidekazu; Kobayashi, Shū

    2015-04-01

    Chemical manufacturing is conducted using either batch systems or continuous-flow systems. Flow systems have several advantages over batch systems, particularly in terms of productivity, heat and mixing efficiency, safety, and reproducibility. However, for over half a century, pharmaceutical manufacturing has used batch systems because the synthesis of complex molecules such as drugs has been difficult to achieve with continuous-flow systems. Here we describe the continuous-flow synthesis of drugs using only columns packed with heterogeneous catalysts. Commercially available starting materials were successively passed through four columns containing achiral and chiral heterogeneous catalysts to produce (R)-rolipram, an anti-inflammatory drug and one of the family of γ-aminobutyric acid (GABA) derivatives. In addition, simply by replacing a column packed with a chiral heterogeneous catalyst with another column packed with the opposing enantiomer, we obtained antipole (S)-rolipram. Similarly, we also synthesized (R)-phenibut, another drug belonging to the GABA family. These flow systems are simple and stable with no leaching of metal catalysts. Our results demonstrate that multistep (eight steps in this case) chemical transformations for drug synthesis can proceed smoothly under flow conditions using only heterogeneous catalysts, without the isolation of any intermediates and without the separation of any catalysts, co-products, by-products, and excess reagents. We anticipate that such syntheses will be useful in pharmaceutical manufacturing.

  5. Continuous-flow precipitation of hydroxyapatite at 37 °C in a meso oscillatory flow reactor

    OpenAIRE

    Castro, Filipa; Ferreira, António; Rocha, Fernando; A.A. Vicente; Teixeira, J. A.

    2013-01-01

    Continuous-flow precipitation of hydroxyapatite (HAp) was investigated in a meso oscillatory flow reactor (meso- OFR) and in a scaled-up meso-OFR, obtained by associating in series eight vertical meso-ORFs. Experiments were carried out under near-physiological conditions of temperature and pH, using fixed frequency ( f = 0.83 Hz) and amplitude (x0 = 4.5 mm), and varying the residence time from 0.4 to 6.7 min. It has been shown that the mean particle size and the aggregation degree of...

  6. Structure and Function of the Bi-Directional Bacterial Flagellar Motor

    Directory of Open Access Journals (Sweden)

    Yusuke V. Morimoto

    2014-02-01

    Full Text Available The bacterial flagellum is a locomotive organelle that propels the bacterial cell body in liquid environments. The flagellum is a supramolecular complex composed of about 30 different proteins and consists of at least three parts: a rotary motor, a universal joint, and a helical filament. The flagellar motor of Escherichia coli and Salmonella enterica is powered by an inward-directed electrochemical potential difference of protons across the cytoplasmic membrane. The flagellar motor consists of a rotor made of FliF, FliG, FliM and FliN and a dozen stators consisting of MotA and MotB. FliG, FliM and FliN also act as a molecular switch, enabling the motor to spin in both counterclockwise and clockwise directions. Each stator is anchored to the peptidoglycan layer through the C-terminal periplasmic domain of MotB and acts as a proton channel to couple the proton flow through the channel with torque generation. Highly conserved charged residues at the rotor–stator interface are required not only for torque generation but also for stator assembly around the rotor. In this review, we will summarize our current understanding of the structure and function of the proton-driven bacterial flagellar motor.

  7. Generation and Synthetic Application of Trifluoromethyl Diazomethane Utilizing Continuous Flow Technologies.

    Science.gov (United States)

    Pieber, Bartholomäus; Kappe, C Oliver

    2016-03-01

    A continuous process for the synthesis and inline separation of anhydrous trifluoromethyl diazomethane in a single continuous flow process is presented. The diazo building block is generated from the corresponding amine and NaNO2 under acidic, aqueous conditions and subsequently diffuses through a gas-permeable membrane into an organic stream. To avoid storage and transportation of the hazardous compound, a representative downstream process in a packed-bed reactor yielding highly functionalized building blocks was developed. PMID:26902154

  8. Predicting bulk powder flow dynamics in a continuous mixer operating in transitory regimes

    OpenAIRE

    Ammarcha, Chawki; Gatumel, Cendrine; Dirion, Jean-Louis; Cabassud, Michel; Mizonov, Vadim; Berthiaux, Henri

    2012-01-01

    International audience Over recent years there has been increasing interest in continuous powder mixing processes, due mainly to the development of on-line measurement techniques. However, our understanding of these processes remains limited, particularly with regard to their flow and mixing dynamics. In the present work, we study the behaviour of a pilot-scale continuous mixer during transitory regimes, in terms of hold-up weight and outflow changes. We present and discuss experimental re...

  9. Numerical Polynomial Homotopy Continuation Method to Locate All The Power Flow Solutions

    OpenAIRE

    Mehta, Dhagash; Nguyen, Hung; Turitsyn, Konstantin

    2014-01-01

    The manuscript addresses the problem of finding all solutions of power flow equations or other similar nonlinear system of algebraic equations. This problem arises naturally in a number of power systems contexts, most importantly in the context of direct methods for transient stability analysis and voltage stability assessment. We introduce a novel form of homotopy continuation method called the numerical polynomial homotopy continuation (NPHC) method that is mathematically guaranteed to find...

  10. A finite element modeling on the fluid flow and solidification in a continuous casting process

    Energy Technology Data Exchange (ETDEWEB)

    Kim, T.H.; Kim, D.S. [Hanyang University Graduate School, Seoul (Korea); Choi, H.C. [Agency for Defence Development, Taejon (Korea); Kim, S.W. [Hanyang University, Seoul (Korea); Lee, S.K. [Chung Buk National University, Chungju (Korea)

    1999-07-01

    The coupled turbulent flow and solidification is considered in a typical slab continuous casting process using commercial program FIDAP. Standard {kappa}-{epsilon} turbulence model is modified to decay turbulent viscosity in the mushy zone and laminar viscosity is set to a sufficiently large value at the solid region. This coupled turbulent flow and solidification model also contains thermal contact resistance due to the mold powder and air gap between the strand and mold using an effective thermal conductivity. From the computed flow pattern, the trajectory of inclusion particles was calculated. The comparison between the predicted and experimental solidified shell thickness shows a good agreement. (author). 27 refs., 11 figs., 2 tabs.

  11. SUPERSONIC CONTINUATION OF THE EVERSHED FLOW OUTSIDE A SUNSPOT AS OBSERVED WITH HINODE

    International Nuclear Information System (INIS)

    We report on the discovery of mostly horizontal field channels just outside sunspot penumbrae (in the so-called 'moat' region) that are seen to sustain supersonic flows (line-of-sight component of 6 km s-1). The spectral signature of these supersonic flows corresponds to circular polarization profiles with an additional, satellite, third lobe of the same sign as the parent sunspot' Stokes V blue lobe, for both downflows and upflows. This is consistent with an outward directed flow that we interpret as the continuation of the magnetized Evershed flow outside sunspots at supersonic speeds. In Stokes Q and U, a clear signature of a transverse field connecting the two flow streams is observed. Such an easily detectable spectral signature should allow for a clear identification of these horizontal field channels in other spectropolarimetric sunspot data. For the spot analyzed in this paper, a total of five channels with this spectral signature have been unambiguously found.

  12. Axial and centrifugal continuous-flow rotary pumps: a translation from pump mechanics to clinical practice.

    Science.gov (United States)

    Moazami, Nader; Fukamachi, Kiyotaka; Kobayashi, Mariko; Smedira, Nicholas G; Hoercher, Katherine J; Massiello, Alex; Lee, Sangjin; Horvath, David J; Starling, Randall C

    2013-01-01

    The recent success of continuous-flow circulatory support devices has led to the growing acceptance of these devices as a viable therapeutic option for end-stage heart failure patients who are not responsive to current pharmacologic and electrophysiologic therapies. This article defines and clarifies the major classification of these pumps as axial or centrifugal continuous-flow devices by discussing the difference in their inherent mechanics and describing how these features translate clinically to pump selection and patient management issues. Axial vs centrifugal pump and bearing design, theory of operation, hydrodynamic performance, and current vs flow relationships are discussed. A review of axial vs centrifugal physiology, pre-load and after-load sensitivity, flow pulsatility, and issues related to automatic physiologic control and suction prevention algorithms is offered. Reliability and biocompatibility of the two types of pumps are reviewed from the perspectives of mechanical wear, implant life, hemolysis, and pump deposition. Finally, a glimpse into the future of continuous-flow technologies is presented.

  13. Deconvolution-based resolution enhancement of chemical ice core records obtained by continuous flow analysis

    DEFF Research Database (Denmark)

    Rasmussen, Sune Olander; Andersen, Katrine K.; Johnsen, Sigfus Johann;

    2005-01-01

    Continuous flow analysis (CFA) has become a popular measuring technique for obtaining high-resolution chemical ice core records due to an attractive combination of measuring speed and resolution. However, when analyzing the deeper sections of ice cores or cores from low-accumulation areas, there ...

  14. Catalytic Macrocyclization Strategies Using Continuous Flow: Formal Total Synthesis of Ivorenolide A.

    Science.gov (United States)

    de Léséleuc, Mylène; Godin, Éric; Parisien-Collette, Shawn; Lévesque, Alexandre; Collins, Shawn K

    2016-08-01

    A formal total synthesis of ivorenolide A has been accomplished employing a Z-selective olefin cross metathesis and a macrocyclic Glaser-Hay coupling as key steps. The macrocyclization protocol employed a phase separation/continuous flow manifold whose advantages include catalysis, fast reaction times, high concentrations, and facile scale-up. PMID:27404899

  15. Amination of Aryl Halides and Esters Using Intensified Continuous Flow Processing

    OpenAIRE

    Thomas M. Kohl; Christian H. Hornung; John Tsanaktsidis

    2015-01-01

    Significant process intensification of the amination reactions of aryl halides and esters has been demonstrated using continuous flow processing. Using this technology traditionally difficult amination reactions have been performed safely at elevated temperatures. These reactions were successfully conducted on laboratory scale coil reactor modules with 1 mm internal diameter (ID) and on a preparatory scale tubular reactor with 6 mm ID containing static mixers.

  16. Semi-continuous protein fractionating using Affinity Cross-Flow Filtration

    NARCIS (Netherlands)

    Borneman, Z.; Zhang, W.; Boomgaard, van den Th.; Smolders, C.A.

    2002-01-01

    Protein purification by means of downstream processing is increasingly important. At the University of Twente a semi-continuous process is developed for the isolation of BSA out of crude protein mixtures. For this purpose an automated Affinity Cross-Flow Filtration, ACFF, process is developed. This

  17. Solar oxidation and removal of arsenic--Key parameters for continuous flow applications.

    Science.gov (United States)

    Gill, L W; O'Farrell, C

    2015-12-01

    Solar oxidation to remove arsenic from water has previously been investigated as a batch process. This research has investigated the kinetic parameters for the design of a continuous flow solar reactor to remove arsenic from contaminated groundwater supplies. Continuous flow recirculated batch experiments were carried out under artificial UV light to investigate the effect of different parameters on arsenic removal efficiency. Inlet water arsenic concentrations of up to 1000 μg/L were reduced to below 10 μg/L requiring 12 mg/L iron after receiving 12 kJUV/L radiation. Citrate however was somewhat surprisingly found to promote a detrimental effect on the removal process in the continuous flow reactor studies which is contrary to results found in batch scale tests. The impact of other typical water groundwater quality parameters (phosphate and silica) on the process due to their competition with arsenic for photooxidation products revealed a much higher sensitivity to phosphate ions compared to silicate. Other results showed no benefit from the addition of TiO2 photocatalyst but enhanced arsenic removal at higher temperatures up to 40 °C. Overall, these results have indicated the kinetic envelope from which a continuous flow SORAS single pass system could be more confidently designed for a full-scale community groundwater application at a village level.

  18. Evaluation of wind flow with a nacelle-mounted continuous-wave lidar

    DEFF Research Database (Denmark)

    Medley, John; Slinger, Chris; Barker, Will;

    Nacelle-mounted lidar is becoming widely recognized as a tool with potential for assessing power curves, understanding wind flow characteristics, and controlling turbines. As rotor diameters continue to increase, and the deployment of turbines in complex terrain becomes more widespread, knowledge...

  19. Evaluation of wind flow with a nacelle-mounted, continuous wave wind lidar

    DEFF Research Database (Denmark)

    Medley, John; Barker, Will; Harris, Mike;

    2014-01-01

    Nacelle-mounted lidar is becoming widely recognized as a tool with potential for assessing power curves, understanding wind flow characteristics, and controlling turbines. As rotor diameters continue to increase, and the deployment of turbines in complex terrain becomes more widespread, knowledge...

  20. Series DNA Amplification Using the Continuous-Flow Polymerase Chain Reaction Chip

    Science.gov (United States)

    Joung, Seung-Ryong; Kang, Chi Jung; Kim, Yong-Sang

    2008-02-01

    We proposed a continuous-flow polymerase chain reaction (PCR) chip that can be used for series DNA amplification. The continuous-flow PCR chip has several advantages such as fast thermal cycling, series of amplifications, cost-effective fabrication, portability, and fluorescence detection. The continuous-flow PCR chip is composed of two parts namely poly(dimethylsiloxane) (PDMS) microchannel for sample injection and indium-tin-oxide (ITO) heater/glass chip for thermal cycling. The fabricated microchannel width and depth are 250 and 200 µm, respectively. Also, the total working length of the PDMS microchannel is 1340 mm which is equivalent for 20 cycles of amplification. A 2:2:3 microchannel length ratio for three different temperature zones namely denaturation, annealing, and extension was assigned, respectively. Upon the operation of the fabricated continuous-flow PCR chip, the amplification of plasmid DNA pKS-GFP with 720 base pairs and PG-noswsi with 300 base pairs were found successfully with a total reaction time of 15 min.

  1. Methylation of 2-Naphthol Using Dimethyl Carbonate under Continuous-Flow Gas-Phase Conditions

    Science.gov (United States)

    Tundo, Pietro; Rosamilia, Anthony E.; Arico, Fabio

    2010-01-01

    This experiment investigates the methylation of 2-naphthol with dimethyl carbonate. The volatility of the substrates, products, and co-products allows the reaction to be performed using a continuous-flow gas-phase setup at ambient pressure. The reaction uses catalytic quantities of base, achieves high conversion, produces little waste, and…

  2. Hemodynamic stress echocardiography in patients supported with a continuous-flow left ventricular assist device

    DEFF Research Database (Denmark)

    Andersen, Mads; Gustafsson, Finn; Madsen, Per Lav;

    2010-01-01

    Functional assessment of continuous-flow left ventricular assist devices (LVADs) is usually performed with the patient at rest. This study compared echocardiographic indices of contraction and filling pressure with invasive measures in 12 ambulatory LVAD patients undergoing symptom-limited bicycl...

  3. Continuous flow hydrogenation of nitroarenes, azides and alkenes using maghemite-Pd nanocomposites

    Science.gov (United States)

    Maghemite-supported ultra-fine Pd (1-2 nm) nanoparticles, prepared by a simple co-precipitation method, find application in the catalytic continuous flow hydrogenation of nitroarenes, azides, and alkenes wherein they play an important role in reduction of various functional group...

  4. A continuation method for computing non-linear 3-D free surface flows

    Energy Technology Data Exchange (ETDEWEB)

    Petersson, N.A.

    1993-01-01

    The subject of this paper is a pseudo-arclength continuation method for computing non-linear three-dimensional steady potential flow around a submerged body moving in a infinitely deep liquid at constant speed and distance below the free surface.

  5. Enrichment of denitrifying methane-oxidizing microorganisms using up-flow continuous reactors and batch cultures.

    Directory of Open Access Journals (Sweden)

    Masashi Hatamoto

    Full Text Available Denitrifying anaerobic methane oxidizing (DAMO microorganisms were enriched from paddy field soils using continuous-flow and batch cultures fed with nitrate or nitrite as a sole electron acceptor. After several months of cultivation, the continuous-flow cultures using nitrite showed remarkable simultaneous methane oxidation and nitrite reduction and DAMO bacteria belonging to phylum NC10 were enriched. A maximum volumetric nitrite consumption rate of 70.4±3.4 mg-N·L(-1·day(-1 was achieved with very short hydraulic retention time of 2.1 hour. In the culture, about 68% of total microbial cells were bacteria and no archaeal cells were detected by fluorescence in situ hybridization. In the nitrate-fed continuous-flow cultures, 58% of total microbial cells were bacteria while archaeal cells accounted for 7% of total cell numbers. Phylogenetic analysis of pmoA gene sequence showed that enriched DAMO bacteria in the continuous-flow cultivation had over 98% sequence similarity to DAMO bacteria in the inoculum. In contrast, for batch culture, the enriched pmoA gene sequences had 89-91% sequence similarity to DAMO bacteria in the inoculum. These results indicate that electron acceptor and cultivation method strongly affect the microbial community structures of DAMO consortia.

  6. 42 CFR 84.155 - Airflow resistance test; Type C supplied-air respirator, continuous flow class and Type CE...

    Science.gov (United States)

    2010-10-01

    ... respirator, continuous flow class and Type CE supplied-air respirator; minimum requirements. 84.155 Section... Respirators § 84.155 Airflow resistance test; Type C supplied-air respirator, continuous flow class and Type... shall not exceed 25 mm. (1 inch) of water-column height when the air flow into the...

  7. Rapid continuous flow synthesis of high-quality silver nanocubes and nanospheres

    KAUST Repository

    Mehenni, Hakim

    2013-01-01

    We report a biphasic-liquid segmented continuous flow method for the synthesis of high-quality plasmonic single crystal silver nanocubes and nanospheres. The nanocubes were synthesized with controllable edge lengths from 20 to 48 nm. Single crystal nanospheres with a mean size of 29 nm were obtained by in-line continuous-flow etching of as-produced 39 nm nanocubes with an aqueous solution of FeNO3. In comparison to batch synthesis, the demonstrated processes represent highly scalable reactions, in terms of both production rate and endurance. The reactions were conducted in a commercially available flow-reactor system that is easily adaptable to industrial-scale production, facilitating widespread utilization of the procedure and the resulting nanoparticles. This journal is © The Royal Society of Chemistry 2013.

  8. Simulation of fluid flow and solididification in the funnel type crystalizer of thin slab continuous cast

    Directory of Open Access Journals (Sweden)

    M.H. Zare

    2014-01-01

    Full Text Available The present work models the fluid flow and heat transfer with solidification of a steel in the funnel type mold region of a thin slab steel continuous caster.ªª In current modeling a turbulent fluid flow has been supposed and used K-ɛ model in order to anticipate the heat transfer distribution in mold region. To consider the solidification effects on fluid flow and solid crust, the Darci model was applied, also for outlet heat flow measurement a simple method was used. The fluid flowresults indicate a special flow pattern in the caster for a tetra-furcated nozzle. revealed to have two large downward and upward recirculation zones with a classic double-roll and two small vortices generated by the upward flow from the upper ports of the submerged entry nozzle. Heat transfer results indicate that increasing the continuous casting velocity and reducing submergence depth would lead to reduction in the thichness of the solidified shell while decrease the surface freezingFinally achieved the optimum condition related to heat transfer phenomena and surface distribution

  9. On-demand continuous-flow production of pharmaceuticals in a compact, reconfigurable system.

    Science.gov (United States)

    Adamo, Andrea; Beingessner, Rachel L; Behnam, Mohsen; Chen, Jie; Jamison, Timothy F; Jensen, Klavs F; Monbaliu, Jean-Christophe M; Myerson, Allan S; Revalor, Eve M; Snead, David R; Stelzer, Torsten; Weeranoppanant, Nopphon; Wong, Shin Yee; Zhang, Ping

    2016-04-01

    Pharmaceutical manufacturing typically uses batch processing at multiple locations. Disadvantages of this approach include long production times and the potential for supply chain disruptions. As a preliminary demonstration of an alternative approach, we report here the continuous-flow synthesis and formulation of active pharmaceutical ingredients in a compact, reconfigurable manufacturing platform. Continuous end-to-end synthesis in the refrigerator-sized [1.0 meter (width) × 0.7 meter (length) × 1.8 meter (height)] system produces sufficient quantities per day to supply hundreds to thousands of oral or topical liquid doses of diphenhydramine hydrochloride, lidocaine hydrochloride, diazepam, and fluoxetine hydrochloride that meet U.S. Pharmacopeia standards. Underlying this flexible plug-and-play approach are substantial enabling advances in continuous-flow synthesis, complex multistep sequence telescoping, reaction engineering equipment, and real-time formulation. PMID:27034366

  10. Self-vibration cancellation of a novel bi-directional magnetized NdFeB/magnetostrictive/piezoelectric laminate.

    Science.gov (United States)

    Leung, Chung Ming; Wang, Feifei; Wang, Ya

    2016-06-01

    A novel magnetoelectric (ME) laminated composite structure is proposed in this work, aiming to provide a good self-vibration cancellation performance under the magnetic field detection environment. The proposed structure consists of two Terfenol-D magnetostrictive alloy plates which are revised and length-magnetized by two NdFeB magnets bonded on the top surface of a thickness-polarized Pb(Zr, Ti)O3 (PZT) ceramic plate with separate electrodes. Experiments have shown that great vibration suppression up to 44 dB under harmonic disturbance was observed. The ME coefficient of the proposed structure also reaches up to ∼29 mV/Oe at non-resonance frequency and 758 mV/Oe at resonance frequency of 79 kHz which is ∼2 times larger than the traditional L-T Terfenol-D/PZT bilayer configuration of the same scale. Such performance improvement is achieved based on the bi-directional magnetic field bias (HBias) of two NdFeB magnets in magnetostrictive layer, internal in-series electrical wire connection in piezoelectric layer. The proposed design has great potential to be used for industrial applications associated with heavy environmental vibration noise. PMID:27370467

  11. Self-vibration cancellation of a novel bi-directional magnetized NdFeB/magnetostrictive/piezoelectric laminate

    Science.gov (United States)

    Leung, Chung Ming; Wang, Feifei; Wang, Ya

    2016-06-01

    A novel magnetoelectric (ME) laminated composite structure is proposed in this work, aiming to provide a good self-vibration cancellation performance under the magnetic field detection environment. The proposed structure consists of two Terfenol-D magnetostrictive alloy plates which are revised and length-magnetized by two NdFeB magnets bonded on the top surface of a thickness-polarized Pb(Zr, Ti)O3 (PZT) ceramic plate with separate electrodes. Experiments have shown that great vibration suppression up to 44 dB under harmonic disturbance was observed. The ME coefficient of the proposed structure also reaches up to ˜29 mV/Oe at non-resonance frequency and 758 mV/Oe at resonance frequency of 79 kHz which is ˜2 times larger than the traditional L-T Terfenol-D/PZT bilayer configuration of the same scale. Such performance improvement is achieved based on the bi-directional magnetic field bias (HBias) of two NdFeB magnets in magnetostrictive layer, internal in-series electrical wire connection in piezoelectric layer. The proposed design has great potential to be used for industrial applications associated with heavy environmental vibration noise.

  12. Are there Bi-directional Associations between Depressive Symptoms and C-Reactive Protein in Mid-life Women?

    Science.gov (United States)

    Matthews, Karen A.; Schott, Laura L.; Bromberger, Joyce T.; Cyranowski, Jill M.; Everson-Rose, Susan A.; Sowers, MaryFran

    2009-01-01

    OBJECTIVE: To test whether depressive symptoms are related to subsequent C-reactive protein (CRP) levels and/or whether CRP levels are related to subsequent depressive symptoms in mid-life women. METHODS: Women enrolled in the Study of Women's Health Across the Nation (SWAN) were followed for seven years and had measures of CES-Depression scores and CRP seven times during the follow-up period. Women were pre- or early peri-menopausal at study entry and were of Caucasian, African American, Hispanic, Japanese, or Chinese race/ethnicity. Analyses were restricted to initially healthy women. RESULTS: Longitudinal mixed linear regression models adjusting for age, race, site, time between exams, and outcome variable at year X showed that higher CES-D scores predicted higher subsequent CRP levels and vice versa over a 7-year period. Full multivariate models adjusting for body mass index, physical activity, medications, health conditions, and other covariates showed that higher CRP levels at year X predicted higher CES-D scores at year X+1, p = 0.03. Higher depressive symptoms predicted higher subsequent CRP levels at marginally significant levels, p=0.10. CONCLUSIONS: Higher CRP levels led to higher subsequent depressive symptoms, albeit the effect was small. The study demonstrates the importance of considering bi-directional relationships for depression and other psychosocial factors and risk for heart disease. PMID:19683568

  13. Motile properties of the bi-directional kinesin-5 Cin8 are affected by phosphorylation in its motor domain

    Science.gov (United States)

    Shapira, Ofer; Gheber, Larisa

    2016-01-01

    The Saccharomyces cerevisiae kinesin-5 Cin8 performs essential mitotic functions in spindle assembly and anaphase B spindle elongation. Recent work has shown that Cin8 is a bi-directional motor which moves towards the minus-end of microtubules (MTs) under high ionic strength (IS) conditions and changes directionality in low IS conditions and when bound between anti-parallel microtubules. Previous work from our laboratory has also indicated that Cin8 is differentially phosphorylated during late anaphase at cyclin-dependent kinase 1 (Cdk1)-specific sites located in its motor domain. In vivo, such phosphorylation causes Cin8 detachment from spindles and reduces the spindle elongation rate, while maintaining proper spindle morphology. To study the effect of phosphorylation on Cin8 motor function, we examined in vitro motile properties of wild type Cin8, as well as its phosphorylation using phospho-deficient and phospho-mimic variants, in a single molecule fluorescence motility assay. Analysis was performed on whole cell extracts and on purified Cin8 samples. We found that addition of negative charges in the phospho-mimic mutant weakened the MT-motor interaction, increased motor velocity and promoted minus-end-directed motility. These results indicate that phosphorylation in the catalytic domain of Cin8 regulates its motor function. PMID:27216310

  14. Process intensification of biodiesel production using a continuous oscillatory flow reactor

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, A.P.; Mackley, M.R.; Seliger, T. [University of Cambridge (United Kingdom). Department of Chemical Engineering

    2003-07-01

    Oscillatory flow reactors (OFRs) are a novel type of continuous reactor, consisting of tubes containing equally spaced orifice plate baffles. An oscillatory motion is superimposed upon the net flow of the process fluid, creating flow patterns conducive to efficient heat and mass transfer, whilst maintaining plug flow. Unlike conventional plug flow reactors, where a minimum Reynolds number must be maintained, the degree of mixing is independent of the net flow, allowing long residence times to be achieved in a reactor of greatly reduced length-to-diameter ratio. Many long residence time processes are currently performed in batch, as conventional designs of plug flow reactor prove to be impractical due to their high length-to-diameter ratios, which lead to problems such as high capital cost, large 'footprint', high pumping costs and, also control is difficult. The OFR allows these processes to be converted to continuous, thereby intensifying the process. The transesterification of various natural oils to form 'biodiesel' is a 'long' reaction, usually performed in batch. Conversion to continuous processing should improve the economics of the process, as the improved mixing should generate a better product (rendering the downstream separation processes easier), at lower residence time (reduction in reactor volume). These improvements can decrease the price of 'biodiesel', making it a more realistic competitor to 'petrodiesel'. This paper shows that it is feasible to perform this reaction in an OFR at a lower residence time. The reaction was performed in a pilot-scale plant, using rapeseed oil and methanol as the feedstocks, and NaOH as the catalyst. (author)

  15. Simulation of fluid flow inside a continuous slab-casting machine

    Science.gov (United States)

    Thomas, B. G.; Mika, L. J.; Najjar, F. M.

    1990-04-01

    A finite element model has been developed and applied to compute the fluid flow distribution inside the shell in the mold region of a continuous, steel slab-casting machine. The model was produced with the commercial program FIDAP, which allows this nonlinear, highly turbulent problem to be simulated using the K- ɛ turbulence model. It consists of separate two-dimensional (2-D) models of the nozzle and a section through the mold, facing the broad face. The predicted flow patterns and velocity fields show reasonable agreement with experimental observations and measurements conducted using a transparent plastic water model. The effects of nozzle angle, casting speed, mold width, and turbulence simulation parameters on the flow pattern have been investigated. The overall flow field is relatively insensitive to process parameters.

  16. Numerical Solution of Heat Tranfer Problem with Flow and Solidification in Round Billet Continuous Casting of Steel

    Institute of Scientific and Technical Information of China (English)

    JiahongGUO; XinHong

    1999-01-01

    In this paper,two dimensional unsteady flow and energy equations are employed for simulation of the flow and heat transfer in round billet continuous casting A numerical method is developed,by using finite volume method and equivalent specific heat method to solve the equations of flow and heat transfer with solidification.The numerical result shows that the method of this paper is efficient for analyzing the flow and heat transfer with solidification of round billet continuous casting.

  17. Contactless Inductive Flow Tomography: Brief History and Recent Developments in Its Application to Continuous Casting

    Directory of Open Access Journals (Sweden)

    Matthias Ratajczak

    2014-01-01

    Full Text Available The contactless inductive flow tomography (CIFT aims at reconstructing the velocity field of electrically conducting fluids, with special focus on applications in metallurgy and crystal growth technologies. The method relies on the induction of secondary magnetic fields if the moving fluid is exposed to a primary magnetic field. The theoretical foundation of the method is delineated, and some early experiments on the reconstruction of the three-dimensional flow in a cylinder are sketched. Then, the recent efforts to apply CIFT to various model problems in connection with the continuous casting of steel are summarized.

  18. Purification and concentration of influenza inactivated viruses by continuous-flow zonal centrifugation.

    Science.gov (United States)

    Mistretta, A P; Crovari-Cuneo, P; Giacometti, G; Sacchi, G; Strozzi, F

    1975-01-01

    A mathod is described for the purification, on an industrial scale, of influenza viruses grown in allantoic cavity of embryonated eggs. The mehtod consists of combining continuous-flow centrifugation with zonal centrifugation in a sucrose (36.6 per cent-52.5 per cent w/v) density gradient. The sample flow rate is approximately 3.7 litres/h and the volumes treated vary between 3 and 33 litres of allantoic fluid. Both the recovery of the virus and the degree of concentration and purification result satisfactory.

  19. Increase in circadian variation after continuous-flow ventricular assist device implantation.

    Science.gov (United States)

    Slaughter, Mark S; Ising, Michael S; Tamez, Daniel; O'Driscoll, Gerry; Voskoboynikov, Neil; Bartoli, Carlo R; Koenig, Steven C; Giridharan, Guruprasad A

    2010-06-01

    The circadian rhythm of varying blood pressure and heart rate is attenuated or absent in patients with severe heart failure. In 28 patients supported by a left ventricular assist device (LVAD) for at least 30 days, a restoration of the circadian rhythm was demonstrated by a consistent nocturnal decrease, and then increase, of the LVAD flow while at a constant LVAD speed. The return of the circadian rhythm has implications for cardiac recovery, and the observation indicates that the continuous-flow LVAD has an intrinsic automatic response to physiologic demands. PMID:20207167

  20. C1-Continuous relative permeability and hybrid upwind discretization of three phase flow in porous media

    Science.gov (United States)

    Lee, S. H.; Efendiev, Y.

    2016-10-01

    Three-phase flow in a reservoir model has been a major challenge in simulation studies due to slowly convergent iterations in Newton solution of nonlinear transport equations. In this paper, we examine the numerical characteristics of three-phase flow and propose a consistent, "C1-continuous discretization" (to be clarified later) of transport equations that ensures a convergent solution in finite difference approximation. First, we examine three-phase relative permeabilities that are critical in solving nonlinear transport equations. Three-phase relative permeabilities are difficult to measure in the laboratory, and they are often correlated with two-phase relative permeabilities (e.g., oil-gas and water-oil systems). Numerical convergence of non-linear transport equations entails that three-phase relative permeability correlations are a monotonically increasing function of the phase saturation and the consistency conditions of phase transitions are satisfied. The Modified Stone's Method II and the Linear Interpolation Method for three-phase relative permeability are closely examined for their mathematical properties. We show that the Linear Interpolation Method yields C1-continuous three-phase relative permeabilities for smooth solutions if the two phase relative permeabilities are monotonic and continuously differentiable. In the second part of the paper, we extend a Hybrid-Upwinding (HU) method of two-phase flow (Lee, Efendiev and Tchelepi, ADWR 82 (2015) 27-38) to three phase flow. In the HU method, the phase flux is divided into two parts based on the driving forces (in general, it can be divided into several parts): viscous and buoyancy. The viscous-driven and buoyancy-driven fluxes are upwinded differently. Specifically, the viscous flux, which is always co-current, is upwinded based on the direction of the total velocity. The pure buoyancy-induced flux is shown to be only dependent on saturation distributions and counter-current. In three-phase flow, the

  1. Contactless inductive flow tomography: basic principles and first applications in the experimental modelling of continuous casting

    Science.gov (United States)

    Stefani, F.; Eckert, S.; Ratajczak, M.; Timmel, K.; Wondrak, T.

    2016-07-01

    Contactless inductive flow tomography (CIFT) aims at reconstructing the flow structure of a liquid metal from the magnetic fields measured at various positions outside the fluid body which are induced by the flow under the influence of one or multiple applied magnetic fields. We recap the basic mathematical principles of CIFT and the results of an experiment in which the propeller-driven three-dimensional flow in a cylindrical had been reconstructed. We also summarize the recent activities to utilize CIFT in various problems connected with the experimental simulation of the continuous casting process. These include flow reconstructions in single-phase and two-phase flow problems in the Mini-LIMMCAST model of slab-casting, studies of the specific effects of an electromagnetic stirrer attached to the Submerged Entry Nozzle (SEN), as well as first successful applications of CIFT on the background of a strong electromagnetic brake field. We conclude by discussing some remaining obstacles for the deployment of CIFT in a real caster.

  2. Validation of a continuous penile blood-flow measurement by pulse-volume-plethysmography.

    Science.gov (United States)

    Lavoisier, P; Barbe, R; Gally, M

    2002-04-01

    Today, in the assessment of cavernous artery blood-flow, the most commonly used technique is Doppler ultrasound velocimetry (continuous, pulsed, color-coded or power), which is often considered as the gold standard. Plethysmographic techniques and radioactive tracers have been widely used for the assessment of global penis flow variations but are not adequate for continuous blood-flow measurement. A new pulse-volume plethysmographic (PVP) device using a water-filled penile cuff was employed to assess continuous blood-flow measurement in the penis. Simultaneously Doppler velocity was recorded and served as a gold standard. A penile water-cuff is connected through a pressure tube to a three-way tap. The pulse-volume changes in the penile water-cuff are measured by means of a latex membrane placed over one of the three-way taps. The displacements of the latex are recorded by a photoplethysmograph. The third tap is connected to a 5 l perfusion bag placed 30 cm above the penis so as to maintain constant pressure in the whole device whatever the penis volume. Twenty-four volunteers were tested. The Doppler velocity signal and pulse volume of cavernous arteries were measured simultaneously after PGE1 intra-cavernous injection. Blood-flow variations were induced by increasing penis artery compression with a second penile water-cuff used as a tourniquet fitted onto the penis root, and the pressure of which could be modified by a water-filled syringe. The amplitude of the plethysmographic pulse-volume signal and the area under the Doppler velocity signal were correlated. The inter-patient (n=24) correlation ranged from 0.455 to 0.904, with a mean correlation of 0.704 and P<0.0001. PVP measurement by a water-filled cuff was validated by ultrasound velocimetry. This new continuous, non-invasive and easy-to-use technique enables physiological and physiopathological flow-measurement during sleep, under visual sexual stimulation (VSS), or following artificial erection

  3. Development of tailored hydrogels using RAFT polymerization in continuous flow microreactor

    OpenAIRE

    Machado, Carla; Oliveira, Tânia; Reitor, Patrícia; de Oliveira, Daniela; Freitas, Filipa; Kadhirvel, Porkodi; Dias, Rolando; Costa, Mário

    2014-01-01

    This research is devoted to the development of tools aiding the production of smart hydrogels with tailored molecular architecture and properties. Molecular imprinting, RAFT polymerization and operation in continuous flow microreactor are individually considered and also simultaneously combined in order to try the synthesis of materials with improved performance. FCT and FEDER under Programme COMPETE (Project PEst-C/EQB/LA0020/2013), QREN, ON2 and FEDER (Project NORTE-07-0162-FEDER-000050)...

  4. Continuous-flow enantioselective α-aminoxylation of aldehydes catalyzed by a polystyrene-immobilized hydroxyproline

    Directory of Open Access Journals (Sweden)

    Xacobe C. Cambeiro

    2011-10-01

    Full Text Available The application of polystyrene-immobilized proline-based catalysts in packed-bed reactors for the continuous-flow, direct, enantioselective α-aminoxylation of aldehydes is described. The system allows the easy preparation of a series of β-aminoxy alcohols (after a reductive workup with excellent optical purity and with an effective catalyst loading of ca. 2.5% (four-fold reduction compared to the batch process working at residence times of ca. 5 min.

  5. Growth and Methane Oxidation Rates of Anaerobic Methanotrophic Archaea in a Continuous-Flow Bioreactor

    OpenAIRE

    Peter R. Girguis; Orphan, Victoria J; Hallam, Steven J.; DeLong, Edward F

    2003-01-01

    Anaerobic methanotrophic archaea have recently been identified in anoxic marine sediments, but have not yet been recovered in pure culture. Physiological studies on freshly collected samples containing archaea and their sulfate-reducing syntrophic partners have been conducted, but sample availability and viability can limit the scope of these experiments. To better study microbial anaerobic methane oxidation, we developed a novel continuous-flow anaerobic methane incubation system (AMIS) that...

  6. Microfluidic continuous-flow radiosynthesis of [18F]FPEB suitable for human PET imaging

    Science.gov (United States)

    Liang, Steven H.; Yokell, Daniel L.; Jackson, Raul N.; Rice, Peter A.; Callahan, Ronald; Johnson, Keith A.; Alagille, David; Tamagnan, Gilles; Collier, Thomas Lee; Vasdev, Neil

    2014-01-01

    The synthesis of fluorine-18 labeled 3-fluoro-5-[(pyridin-3-yl)ethynyl] benzonitrile ([18F]FPEB) for imaging metabotropic glutamate receptor subtype type 5 (mGluR5) was achieved with a commercial continuous-flow microfluidics device. This work represents the first positron emission tomography (PET) radiopharmaceutical that is suitable for human use with this technology. We also describe a validated synthesis of [18F]FPEB with a commercial reactor-based system. PMID:25431646

  7. Investigation of power flow in a continuous floating raft isolation system

    Institute of Scientific and Technical Information of China (English)

    SONG Kongjie; MAO Yinghong; LIN Li

    2001-01-01

    A general dynamic model of a floating raft isolation system with multiple machines and supports is established. Considering the coupling of the foundation in high frequency and basing on the mobility analysis of substructures, the expression of the power flow transmission spectrum of the finite continuous isolation system of asymmetry is derived. At the same time the mathematical calculation and analysis by figure are made to find the rules related to the isolation effect in the case of different parameters of the system.

  8. Holographic interferometry and its application in visualizing particle movements in continuous flow

    OpenAIRE

    Magnussen, Stian

    2004-01-01

    This thesis presents the work performed at the Department of Physics and Technology at the University of Bergen during a collaborative project funded by Statoil. The parties in this collaboration were the University of Bergen, Rogaland Research (RF) and the University College of Stavanger The overall project objective was to visualize and quantify particle motion in continuous flow. At the Department of Physics and Technology we have built a closed-loop tank system consisting of three gla...

  9. Development of Safe and Scalable Continuous-Flow Methods for Palladium-Catalyzed Aerobic Oxidation Reactions†

    OpenAIRE

    Ye, Xuan; Johnson, Martin D.; Diao, Tianning; Yates, Matthew H.; Stahl, Shannon S.

    2010-01-01

    The synthetic scope and utility of Pd-catalyzed aerobic oxidation reactions has advanced significantly over the past decade, and these reactions have potential to address important green-chemistry challenges in the pharmaceutical industry. This potential has been unrealized, however, because safety concerns and process constraints hinder large-scale applications of this chemistry. These limitations are addressed by the development of a continuous-flow tube reactor, which has been demonstrated...

  10. A Microfluidic Device for Continuous-Flow Magnetically Controlled Capture and Isolation of Microparticles

    OpenAIRE

    Zhou, Yao; Wang, Yi; Lin, Qiao

    2010-01-01

    This paper presents a novel microfluidic device that exploits magnetic manipulation for integrated capture and isolation of microparticles in continuous flow. The device, which was fabricated from poly(dimethylsiloxane) (PDMS) by soft-lithography techniques, consists of an incubator and a separator integrated on a single chip. The incubator is based on a novel scheme termed target acquisition by repetitive traversal (TART), in which surface-functionalized magnetic beads repetitively traverse ...

  11. Biological anoxic phosphorus removal in a continuous-flow external nitrification activated sludge system

    Energy Technology Data Exchange (ETDEWEB)

    Kapagiannidis, A. G.; Aivasidis, A.

    2009-07-01

    Application of Biological Nutrient Removal (BNR) process in wastewater treatment is necessitated for the protection of water bodies from eutrophication. an alternative BNR method is tested for simultaneous Carbon (C), Nitrogen (N) and Phosphorus (P) removal in a continuous-flow bench scale plant for municipal wastewater treatment. The plant operation is based on the activity of two microbial populations which grow under different operational conditions (two sludge system). (Author)

  12. Rapid Synthesis of Aryl Fluorides in Continuous Flow through the Balz-Schiemann Reaction.

    Science.gov (United States)

    Park, Nathaniel H; Senter, Timothy J; Buchwald, Stephen L

    2016-09-19

    The Balz-Schiemann reaction remains a highly utilized means for preparing aryl fluorides from anilines. However, the limitations associated with handling aryl diazonium salts often hinder both the substrate scope and scalability of this reaction. To address this, a new continuous flow protocol was developed that eliminates the need to isolate the aryl diazonium salts. The new process has enabled the fluorination of an array of aryl and heteroaryl amines. PMID:27558308

  13. Domestic wastewater treatment using multi-electrode continuous flow MFCs with a separator electrode assembly design

    KAUST Repository

    Ahn, Yongtae

    2012-10-11

    Treatment of domestic wastewater using microbial fuel cells (MFCs) will require reactors with multiple electrodes, but this presents unique challenges under continuous flow conditions due to large changes in the chemical oxygen demand (COD) concentration within the reactor. Domestic wastewater treatment was examined using a single-chamber MFC (130 mL) with multiple graphite fiber brush anodes wired together and a single air cathode (cathode specific area of 27 m2/m3). In fed-batch operation, where the COD concentration was spatially uniform in the reactor but changed over time, the maximum current density was 148 ± 8 mA/m2 (1,000 Ω), the maximum power density was 120 mW/m2, and the overall COD removal was >90 %. However, in continuous flow operation (8 h hydraulic retention time, HRT), there was a 57 % change in the COD concentration across the reactor (influent versus effluent) and the current density was only 20 ± 13 mA/m2. Two approaches were used to increase performance under continuous flow conditions. First, the anodes were separately wired to the cathode, which increased the current density to 55 ± 15 mA/m2. Second, two MFCs were hydraulically connected in series (each with half the original HRT) to avoid large changes in COD among the anodes in the same reactor. The second approach improved current density to 73 ± 13 mA/m2. These results show that current generation from wastewaters in MFCs with multiple anodes, under continuous flow conditions, can be improved using multiple reactors in series, as this minimizes changes in COD in each reactor. © 2012 Springer-Verlag Berlin Heidelberg.

  14. Continuous surface force based lattice Boltzmann equation method for simulating thermocapillary flow

    CERN Document Server

    Zheng, Lin; Zhai, Qinglan

    2014-01-01

    In this paper, we extend a lattice Boltzmann equation (LBE) with continuous surface fore (CSF) to simulate thermocapillary flows. The model is designed on our previous CSF LBE for athermal two phase flow, in which the interfacial tension forces and the Marangoni stresses as the results of the interface interactions between different phases are described by a conception of CSF. In this model, the sharp interfaces between different phases are separated by a narrow transition layers, and the kinetics and morphology evolution of phase separation would be characterized by an order parameter visa Cahn-Hilliard equation which is solved in the frame work of LBE. The scalar convection-diffusion equation for temperature field is also solved by thermal LBE. The models are validated by thermal two layered Poiseuille flow, and a two superimposed planar fluids at negligibly small Reynolds and Marangoni numbers for the thermocapillary driven convection, which have analytical solutions for the velocity and temperature. Then ...

  15. Changes of a continuous character caused by gene flow. A Monte Carlo study

    Science.gov (United States)

    Sznajd-Weron, Katarzyna; Pȩkalski, Andrzej

    We introduce a model of a large, sexual, population in which partners for reproduction are chosen randomly, without any bias. This large population is composed of two groups of local populations living in different environments and being in contact. We propose a dynamic equation describing, like the existing one for the allele frequency, the temporal changes of a continuous character due to gene flow, i.e. the transfer of the allels resulting from migration of individuals between the populations, and natural selection. We show that the gene flow can be described by the linear term in the proposed equation and the natural selection by the nonlinear term. Additional killing rule introduces a random factor into our model. We discuss the role of both factors (gene flow and selection) on the structure of the population, i.e. spatial distribution of the considered character and the resulting from it existence of hybrid zones. We use the standard Monte Carlo simulations.

  16. On-chip determination of C-reactive protein using magnetic particles in continuous flow.

    Science.gov (United States)

    Phurimsak, Chayakom; Tarn, Mark D; Peyman, Sally A; Greenman, John; Pamme, Nicole

    2014-11-01

    We demonstrate the application of a multilaminar flow platform, in which functionalized magnetic particles are deflected through alternating laminar flow streams of reagents and washing solutions via an external magnet, for the rapid detection of the inflammatory biomarker, C-reactive protein (CRP). The two-step sandwich immunoassay was accomplished in less than 60 s, a vast improvement on the 80-300 min time frame required for enzyme-linked immunosorbent assays (ELISA) and the 50 min necessary for off-chip magnetic particle-based assays. The combination of continuous flow and a stationary magnet enables a degree of autonomy in the system, while a detection limit of 0.87 μg mL(-1) makes it suitable for the determination of CRP concentrations in clinical diagnostics. Its applicability was further proven by assaying real human serum samples and comparing those results to values obtained using standard ELISA tests.

  17. [Quick Start-up and Sustaining of Shortcut Nitrification in Continuous Flow Reactor].

    Science.gov (United States)

    Wu, Peng; Zhang Shi-ying; Song, Yin-ling; Xu, Yue-zhong; Shen, Yao-liang

    2016-04-15

    How to achieve fast and stable startup of shortcut nitrification has a very important practical value for treatment of low C/N ratio wastewater. Thus, the quick start-up and sustaining of shortcut nitrification were investigated in continuous flow reactor targeting at the current situation of urban wastewater treatment plant using a continuous flow process. The results showed that quick start-up of shortcut nitrification could be successfully achieved in a continuous flow reactor after 60 days' operation with intermittent aeration and controlling of three stages of stop/aeration time (15 min/45 min, 45 min/45 min and 30 min/30 min). The nitrification rates could reach 90% or 95% respectively, while influent ammonia concentrations were 50 or 100 mg · L⁻¹ with stop/aeration time of 30 min/30 min. In addition, intermittent aeration could inhibit the activity of nitrite oxidizing bacteria (NOB), while short hydraulic retention time (HRT) may wash out NOB. And a combined use of both measures was beneficial to sustain shortcut nitrification. PMID:27548971

  18. Comparison between continuous and localized methods to evaluate the flow rate through containment concrete structures

    International Nuclear Information System (INIS)

    Highlights: • The contribution focuses on the gas transfer through reinforced concrete structures. • A continuous approach with a damage–permeability law is investigated. • It is significant, for this case, only when the damage variable crosses the section. • In this case, two localized approaches are compared. • It helps at evaluating a “reference” crack opening for engineering laws. - Abstract: In this contribution, different techniques are compared to evaluate the gas flow rate through a representative section of a reinforced and prestressed concrete containment structure. A continuous approach is first applied which is based on the evaluation of the gas permeability as a function of the damage variable. The calculations show that the flow rate becomes significant only when the damage variable crosses the section. But in this situation, the continuous approach is no longer fully valid. That is why localized approaches, based on a fine description of the crack openings, are then investigated. A comparison between classical simplified laws (Poiseuille flow) and a more refined model which takes into account the evolution of the crack opening in the depth of the section enables to define the validity domain of the simplified laws and especially the definition of the associated “reference opening”

  19. Rapid detection of genetically modified organisms on a continuous-flow polymerase chain reaction microfluidics.

    Science.gov (United States)

    Li, Yuyuan; Xing, Da; Zhang, Chunsun

    2009-02-01

    The ability to perform DNA amplification on a microfluidic device is very appealing. In this study, a compact continuous-flow polymerase chain reaction (PCR) microfluidics was developed for rapid analysis of genetically modified organisms (GMOs) in genetically modified soybeans. The device consists of three pieces of copper and a transparent polytetrafluoroethylene capillary tube embedded in the spiral channel fabricated on the copper. On this device, the P35S and Tnos sequences were successfully amplified within 9min, and the limit of detection of the DNA sample was estimated to be 0.005 ng microl(-1). Furthermore, a duplex continuous-flow PCR was also reported for the detection of the P35S and Tnos sequences in GMOs simultaneously. This method was coupled with the intercalating dye SYBR Green I and the melting curve analysis of the amplified products. Using this method, temperature differences were identified by the specific melting temperature values of two sequences, and the limit of detection of the DNA sample was assessed to be 0.01 ng microl(-1). Therefore, our results demonstrated that the continuous-flow PCR assay could discriminate the GMOs in a cost-saving and less time-consuming way.

  20. PRELIMINARY DESIGN OF OSCILLATORY FLOW BIODIESEL REACTOR FOR CONTINUOUS BIODIESEL PRODUCTION FROM JATROPHA TRIGLYCERIDES

    Directory of Open Access Journals (Sweden)

    AZHARI T. I. MOHD. GHAZI

    2008-08-01

    Full Text Available The concept of a continuous process in producing biodiesel from jatropha oil by using an Oscillatory Flow Biodiesel Reactor (OFBR is discussed in this paper. It has been recognized that the batch stirred reactor is a primary mode used in the synthesis of biodiesel. However, pulsatile flow has been extensively researcehed and the fundamental principles have been successfully developed upon which its hydrodynamics are based. Oscillatory flow biodiesel reactor offers precise control of mixing by means of the baffle geometry and pulsation which facilitates to continuous operation, giving plug flow residence time distribution with high turbulence and enhanced mass and heat transfer. In conjunction with the concept of reactor design, parameters such as reactor dimensions, the hydrodynamic studies and physical properties of reactants must be considered prior to the design work initiated recently. The OFBR reactor design involves the use of simulation software, ASPEN PLUS and the reactor design fundamentals. Following this, the design parameters shall be applied in fabricating the OFBR for laboratory scale biodiesel production.

  1. Removal of natural organic matter and arsenic from water by electrocoagulation/flotation continuous flow reactor.

    Science.gov (United States)

    Mohora, Emilijan; Rončević, Srdjan; Dalmacija, Božo; Agbaba, Jasmina; Watson, Malcolm; Karlović, Elvira; Dalmacija, Milena

    2012-10-15

    The performance of the laboratory scale electrocoagulation/flotation (ECF) reactor in removing high concentrations of natural organic matter (NOM) and arsenic from groundwater was analyzed in this study. An ECF reactor with bipolar plate aluminum electrodes was operated in the horizontal continuous flow mode. Electrochemical and flow variables were optimized to examine ECF reactor contaminants removal efficiency. The optimum conditions for the process were identified as groundwater initial pH 5, flow rate=4.3 l/h, inter electrode distance=2.8 cm, current density=5.78 mA/cm(2), A/V ratio=0.248 cm(-1). The NOM removal according to UV(254) absorbance and dissolved organic matter (DOC) reached highest values of 77% and 71% respectively, relative to the raw groundwater. Arsenic removal was 85% (6.2 μg As/l) relative to raw groundwater, satisfying the drinking water standards. The specific reactor electrical energy consumption was 17.5 kWh/kg Al. The specific aluminum electrode consumption was 66 g Al/m(3). According to the obtained results, ECF in horizontal continuous flow mode is an energy efficient process to remove NOM and arsenic from groundwater. PMID:22902131

  2. Factors influencing arsenic and nitrate removal from drinking water in a continuous flow electrocoagulation (EC) process

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, N. Sanjeev [Civil Engineering Department, IIT Kharagpur, Kharagpur 721302 (India); Goel, Sudha, E-mail: sudhagoel@civil.iitkgp.ernet.in [Civil Engineering Department, IIT Kharagpur, Kharagpur 721302 (India)

    2010-01-15

    An experimental study was conducted under continuous flow conditions to evaluate some of the factors influencing contaminant removal by electrocoagulation (EC). A bench-scale simulation of drinking water treatment was done by adding a filtration column after a rectangular EC reactor. Contaminant removal efficiency was determined for voltages ranging from 10 to 25 V and a comparative study was done with distilled water and tap water for two contaminants: nitrate and arsenic(V). Maximum removal efficiency was 84% for nitrate at 25 V and 75% for arsenic(V) at 20 V. No significant difference in contaminant removal was observed in tap water versus distilled water. Increase in initial As(V) concentration from 1 ppm to 2 ppm resulted in a 10% increase in removal efficiency. Turbidity in the EC reactor effluent was 52 NTU and had to be filtered to achieve acceptable levels of final turbidity (5 NTU) at steady-state. The flow regime in the continuous flow reactor was also evaluated in a tracer study to determine whether it is a plug flow reactor (PFR) or constantly stirred tank reactor (CSTR) and the results show that this reactor was close to an ideal CSTR, i.e., it was fairly well-mixed.

  3. Active Continuous-Flow Micromixer Using an External Braille Pin Actuator Array

    Directory of Open Access Journals (Sweden)

    Junichi Miwa

    2013-03-01

    Full Text Available We present a continuous-flow active micromixer based on channel-wall deflection in a polydimethylsiloxane (PDMS chip for volume flows in the range up to 2 μL s−1 which is intended as a novel unit operation for the microfluidic Braille pin actuated platform. The chip design comprises a main microchannel connected to a series of side channels with dead ends aligned on the Braille pins. Computer-controlled deflection of the side-channel walls induces chaotic advection in the main-channel, which substantially accelerates mixing in low-Reynolds number flow. Sufficient mixing (mixing index MI below 0.1 of volume flows up to 0.5 μL s−1 could be achieved within residence times ~500 ms in the micromixer. As an application, continuous dilution of a yeast cell sample by a ratio down to 1:10 was successfully demonstrated. The mixer is intended to serve as a component of bio-analytical devices or as a unit operation in the microfluidic Braille pin actuated platform.

  4. Epidural blood flow and regression of sensory analgesia during continuous postoperative epidural infusion of bupivacaine

    DEFF Research Database (Denmark)

    Mogensen, T; Højgaard, L; Scott, N B;

    1988-01-01

    Epidural blood flow was measured in seven patients undergoing elective abdominal surgery during combined lumbar epidural and general anesthesia. After an initial dose of 20 ml plain bupivacaine 0.5%, a continuous epidural infusion of bupivacaine 0.5% (8 ml/hr) was given for 16 hours...... for postoperative pain relief. The epidural blood flow was measured by a local 133Xe clearance technique in which 15-35 MBq 133Xe diluted in 1 ml saline was injected through the epidural catheter on the day before surgery (no bupivacaine), 30 minutes after the initial dose of bupivacaine on the morning before...... surgery, and 8, 12, and 16 hours later during the continuous infusion. Initial blood flow was 6.0 +/- 0.7 ml/min per 100 g tissue (mean +/- SEM). After epidural bupivacaine, blood flow increased in all seven patients to 7.4 +/- 0.7 ml (P less than 0.02). Initial level of sensory analgesia was T4.5 +/- 0...

  5. Using Flow Electrodes in Multiple Reactors in Series for Continuous Energy Generation from Capacitive Mixing

    KAUST Repository

    Hatzell, Marta C.

    2014-12-09

    Efficient conversion of “mixing energy” to electricity through capacitive mixing (CapMix) has been limited by low energy recoveries, low power densities, and noncontinuous energy production resulting from intermittent charging and discharging cycles. We show here that a CapMix system based on a four-reactor process with flow electrodes can generate constant and continuous energy, providing a more flexible platform for harvesting mixing energy. The power densities were dependent on the flow-electrode carbon loading, with 5.8 ± 0.2 mW m–2 continuously produced in the charging reactor and 3.3 ± 0.4 mW m–2 produced in the discharging reactor (9.2 ± 0.6 mW m–2 for the whole system) when the flow-electrode carbon loading was 15%. Additionally, when the flow-electrode electrolyte ion concentration increased from 10 to 20 g L–1, the total power density of the whole system (charging and discharging) increased to 50.9 ± 2.5 mW m–2.

  6. Insulin-like Growth Factor-I and Slow, Bi-directional Perfusion Enhance the Formation of Tissue-Engineered Cardiac Grafts

    OpenAIRE

    Cheng, Mingyu; Moretti, Matteo; Engelmayr, George C.; Freed, Lisa E.

    2008-01-01

    Biochemical and mechanical signals enabling cardiac regeneration can be elucidated using in vitro tissue-engineering models. We hypothesized that insulin-like growth factor-I (IGF) and slow, bi-directional perfusion could act independently and interactively to enhance the survival, differentiation, and contractile performance of tissue-engineered cardiac grafts. Heart cells were cultured on three-dimensional porous scaffolds in medium with or without supplemental IGF and in the presence or ab...

  7. The association between attachment style and uni- and bi-directional pursuer-distancer patterns in couples: A clinical sample of couples in counseling

    OpenAIRE

    Davies, Lorin Christopher

    2004-01-01

    This study examined the relationship between adult attachment style and pursuer-distancer patterns in couples. Both uni- and bi-directional pursuer-distancer patterns were studied. Participants were 67 individuals (including 32 couples) in therapy. Each partner, independent of the other, completed an anonymous questionnaire containing the Multi-item Measure of Adult Romantic Attachment (Brennan, Clark, & Shaver, 1998) and a four-item measure of pursuer-distancer pattern designed for this s...

  8. Neutralization of Alkaline Wasterwater with CO{sub 2} in a continuous flow jet loop reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Dae Yeop; Kim, Mi Ran; Lim, Jun Heok; Lee, Tae Yoon; Lee, Jea Keun [Pukyong National Univ., Busan (Korea, Republic of)

    2016-02-15

    This paper investigates the feasibility of applying the jet loop reactor for the neutralization of alkaline wastewater using carbon dioxide (CO2). In this study, pH changes and CO2 removal characteristics were examined by changing influent flow rate of alkaline wastewater (initial pH=10.1) and influent CO2 flow rates. Influent flow rates of alkaline wastewater (QL,in) ranged between 0.9 and 6.6 L/min, and inlet gas flow rate (QG,in) of 1 and 6 L/min in a lab-scale continuous flow jet loop reactor. The outlet pH of wastewater was maintained at 7.2 when the ratio (QL,in/QG,in) of QL,in and QG,in was 1.1. However, the CO2 removal efficiency and the outlet pH of wastewater were increased when QL,in/QG,in ratio was higher than 1.1. Throughout the experiments, the maximum CO2 removal efficiency and the outlet pH of wastewater were 98.06% and 8.43 at the condition when QG,in and QL,in were 2 L/min and 4 L/min, respectively.

  9. Influence of System Variables on the Heating Characteristics of Water during Continuous Flow Microwave Heating

    Directory of Open Access Journals (Sweden)

    Hosahalli S. Ramaswamy

    2011-01-01

    Full Text Available A domestic microwave oven (1000 W was modified to permit the continuous flow of liquids run through a helical coil centrally located inside the oven cavity. Heating characteristics were evaluated by measuring inlet and outlet temperatures of coil as a function of system variables. The influence of number of turns, coil diameter, tube diameter, pitch and initial temperature were evaluated at different flow rates. The average residence time of water was computed by dividing the coil volume by the volumetric flow rate. The influence of Dean number was evaluated. Results from this study showed that (1 higher number of turns resulted in lower heating rate, lower temperature fluctuations, higher exit temperature and longer time to achieve temperature equilibrium; (2 larger tube or coil diameter gave larger coil volume causing the heating rate to decrease; (3 faster flow rates resulted in lower exit temperatures, lower temperature fluctuation, higher Dean number and slightly higher heating rate; (4 higher initial temperatures resulted in higher exit temperatures; (5 higher Dean number resulted in more uniform heating and slightly higher heating rate. Overall, the coil volume was the more dominant factor affecting heating rate as compared with flow rate and Dean number.

  10. Continuous-flow leach testing method for various nuclear waste forms

    International Nuclear Information System (INIS)

    Nuclear waste is planned to be buried in deep geological repositories. If these repositories were ever invaded by ground water, the waste form could be corroded and the nuclear waste released to the surrounding geologic medium. The rate at which this flowing ground water corrodes the waste form can be studied using the Lawrence Livermore National Laboratory's single-pass continuous-flow leaching test. This repository-relevant leaching test places the waste form of interest into a flowing stream of leachant. The flow rates can be set to approximate the low flow rates encountered in actual aquifers. The leachant contacts the waste only once and then exits the cell where it is collected and analyzed. Such a scheme avoids potential solution saturation problems encountered with static tests. The composition of leachants used with this test has ranged from saturated salt brine to distilled water. Temperature has been varied from 250C to 750C. These values cover the range of ambient temperatures expected at depths of 2 to 3 km. This test was designed to reproduce conditions of a flooded repository in the laboratory. The testing methodology is discussed as well as examples of data obtained from leaching a variety of waste forms under various conditions

  11. Removal of natural organic matter and arsenic from water by electrocoagulation/flotation continuous flow reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mohora, Emilijan, E-mail: emohora@ifc.org [University of Novi Sad Faculty of Sciences, Department of Chemistry, Biochemistry and Environmental Protection, Trg D. Obradovica 3, 21000 Novi Sad (Serbia); Roncevic, Srdjan; Dalmacija, Bozo; Agbaba, Jasmina; Watson, Malcolm; Karlovic, Elvira; Dalmacija, Milena [University of Novi Sad Faculty of Sciences, Department of Chemistry, Biochemistry and Environmental Protection, Trg D. Obradovica 3, 21000 Novi Sad (Serbia)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer A continuous electrocoagulation/flotation reactor was designed built and operated. Black-Right-Pointing-Pointer Highest NOM removal according to UV{sub 254} was 77% relative to raw groundwater. Black-Right-Pointing-Pointer Highest NOM removal accordance to DOC was 71%, relative to raw groundwater. Black-Right-Pointing-Pointer Highest As removal archived was 85% (6.2 {mu}g/l), relative to raw groundwater. Black-Right-Pointing-Pointer Specific reactor energy and electrode consumption was 1.7 kWh/m{sup 3} and 66 g Al/m{sup 3}. - Abstract: The performance of the laboratory scale electrocoagulation/flotation (ECF) reactor in removing high concentrations of natural organic matter (NOM) and arsenic from groundwater was analyzed in this study. An ECF reactor with bipolar plate aluminum electrodes was operated in the horizontal continuous flow mode. Electrochemical and flow variables were optimized to examine ECF reactor contaminants removal efficiency. The optimum conditions for the process were identified as groundwater initial pH 5, flow rate = 4.3 l/h, inter electrode distance = 2.8 cm, current density = 5.78 mA/cm{sup 2}, A/V ratio = 0.248 cm{sup -1}. The NOM removal according to UV{sub 254} absorbance and dissolved organic matter (DOC) reached highest values of 77% and 71% respectively, relative to the raw groundwater. Arsenic removal was 85% (6.2 {mu}g As/l) relative to raw groundwater, satisfying the drinking water standards. The specific reactor electrical energy consumption was 17.5 kWh/kg Al. The specific aluminum electrode consumption was 66 g Al/m{sup 3}. According to the obtained results, ECF in horizontal continuous flow mode is an energy efficient process to remove NOM and arsenic from groundwater.

  12. Bioremoval of trivalent chromium using Bacillus biofilms through continuous flow reactor

    International Nuclear Information System (INIS)

    Highlights: ► Effective bioremoval of Cr(III) using bacterial biofilms. ► Simplified bioreactor was fabricated for the biofilm development and Cr(III) removal. ► Economically feasible substrate like coarse sand and pebbles were used. - Abstract: Present study deals with the applicability of bacterial biofilms for the bioremoval of trivalent chromium from tannery effluents. A continuous flow reactor was designed for the development of biofilms on different substrates like glass beads, pebbles and coarse sand. The parameters for the continuous flow reactor were 20 ml/min flow rate at 30 °C, pH4. Biofilm biomass on the substrates was in the following sequence: coarse sand > pebbles > glass beads (4.8 × 107, 4.5 × 107 and 3.5 × 105 CFU/cm2), which was confirmed by CLSM. Biofilms developed using consortium of Bacillus subtilis and Bacillus cereus on coarse sand had more surface area and was able to remove 98% of Cr(III), SEM-EDX proved 92.60% Cr(III) adsorption on biofilms supported by coarse sand. Utilization of Bacillus biofilms for effective bioremoval of Cr(III) from chrome tanning effluent could be a better option for tannery industry, especially during post chrome tanning operation.

  13. Ultrafast synthesis of isoquercitrin by enzymatic hydrolysis of rutin in a continuous-flow microreactor

    Directory of Open Access Journals (Sweden)

    Wang Jun

    2015-01-01

    Full Text Available Isoquercitrin is a rare flavonol glycoside with a wide range of biological activities and is a key synthetic intermediate for the production of enzymatically modified isoquercitrin. In order to establish an ultrafast bioprocess for obtaining isoquercitrin, a novel continuous flow biosynthesis of isoquercitrin using the hesperidinase-catalyzed hydrolysis of rutin in a glass-polydimethylsiloxane (PDMS microreactor was first carried out. Using the developed microchannel reactor (200μm width, 50μm depth, and 2 m length with one T-shaped inlet and one outlet, the maximum yield of isoquercitrin (98.6% was achieved in a short time (40 min under the following optimum conditions: rutin concentration at 1 g L-1, hesperidinase concentration at 0.1 g mL-1, reaction temperature at 40°C, and a flow rate at 2 μL min-1. The activation energy value Ea of the enzymatic reaction was 4.61 kJ mol-1, and the reaction rate and volumetric productivity were approximately 16.1-fold and 30% higher, respectively, than those in the batch reactor. Thus, the use of a continuous-flow microreactor for the enzymatic hydrolysis of rutin is an efficient and simple approach to achieve a relative high yield of isoquercitrin.

  14. Bioremoval of trivalent chromium using Bacillus biofilms through continuous flow reactor

    Energy Technology Data Exchange (ETDEWEB)

    Sundar, K.; Sadiq, I. Mohammed; Mukherjee, Amitava [Centre for Nanobiotechnology, Nano Bio-Medicine Laboratory School of Bio Sciences and Technology VIT University, Vellore - 632014 (India); Chandrasekaran, N., E-mail: nchandrasekaran@vit.ac.in [Centre for Nanobiotechnology, Nano Bio-Medicine Laboratory School of Bio Sciences and Technology VIT University, Vellore - 632014 (India)

    2011-11-30

    Highlights: Black-Right-Pointing-Pointer Effective bioremoval of Cr(III) using bacterial biofilms. Black-Right-Pointing-Pointer Simplified bioreactor was fabricated for the biofilm development and Cr(III) removal. Black-Right-Pointing-Pointer Economically feasible substrate like coarse sand and pebbles were used. - Abstract: Present study deals with the applicability of bacterial biofilms for the bioremoval of trivalent chromium from tannery effluents. A continuous flow reactor was designed for the development of biofilms on different substrates like glass beads, pebbles and coarse sand. The parameters for the continuous flow reactor were 20 ml/min flow rate at 30 Degree-Sign C, pH4. Biofilm biomass on the substrates was in the following sequence: coarse sand > pebbles > glass beads (4.8 Multiplication-Sign 10{sup 7}, 4.5 Multiplication-Sign 10{sup 7} and 3.5 Multiplication-Sign 10{sup 5} CFU/cm{sup 2}), which was confirmed by CLSM. Biofilms developed using consortium of Bacillus subtilis and Bacillus cereus on coarse sand had more surface area and was able to remove 98% of Cr(III), SEM-EDX proved 92.60% Cr(III) adsorption on biofilms supported by coarse sand. Utilization of Bacillus biofilms for effective bioremoval of Cr(III) from chrome tanning effluent could be a better option for tannery industry, especially during post chrome tanning operation.

  15. Titer-plate formatted continuous flow thermal reactors: Design and performance of a nanoliter reactor.

    Science.gov (United States)

    Chen, Pin-Chuan; Park, Daniel S; You, Byoung-Hee; Kim, Namwon; Park, Taehyun; Soper, Steven A; Nikitopoulos, Dimitris E; Murphy, Michael C

    2010-08-01

    Arrays of continuous flow thermal reactors were designed, configured, and fabricated in a 96-device (12 × 8) titer-plate format with overall dimensions of 120 mm × 96 mm, with each reactor confined to a 8 mm × 8 mm footprint. To demonstrate the potential, individual 20-cycle (740 nL) and 25-cycle (990 nL) reactors were used to perform the continuous flow polymerase chain reaction (CFPCR) for amplification of DNA fragments of different lengths. Since thermal isolation of the required temperature zones was essential for optimal biochemical reactions, three finite element models, executed with ANSYS (v. 11.0, Canonsburg, PA), were used to characterize the thermal performance and guide system design: (1) a single device to determine the dimensions of the thermal management structures; (2) a single CFPCR device within an 8 mm × 8 mm area to evaluate the integrity of the thermostatic zones; and (3) a single, straight microchannel representing a single loop of the spiral CFPCR device, accounting for all of the heat transfer modes, to determine whether the PCR cocktail was exposed to the proper temperature cycling. In prior work on larger footprint devices, simple grooves between temperature zones provided sufficient thermal resistance between zones. For the small footprint reactor array, 0.4 mm wide and 1.2 mm high fins were necessary within the groove to cool the PCR cocktail efficiently, with a temperature gradient of 15.8°C/mm, as it flowed from the denaturation zone to the renaturation zone. With temperature tolerance bands of ±2°C defined about the nominal temperatures, more than 72.5% of the microchannel length was located within the desired temperature bands. The residence time of the PCR cocktail in each temperature zone decreased and the transition times between zones increased at higher PCR cocktail flow velocities, leading to less time for the amplification reactions. Experiments demonstrated the performance of the CFPCR devices as a function of flow

  16. Solar disinfection for the post-treatment of greywater by means of a continuous flow reactor.

    Science.gov (United States)

    Pansonato, Natália; Afonso, Marcos V G; Salles, Carlos A; Boncz, Marc A; Paulo, Paula L

    2011-01-01

    SODIS (solar disinfection) is a low-cost alternative for water decontamination. The method is based on the exposure of water, contained in PET bottles, to direct sunlight, and mainly its UV-A and infrared components. The present research studied SODIS as a low cost alternative for the inactivation of Escherichia coli (E. coli) in treated greywater, aiming at its reuse for more noble applications. Experiments were performed in (i) batch mode (2 L PET-bottles), testing the effect of turbidity on system efficiency and, (ii) in a continuous pilot-scale reactor prototype (51 L, using interconnected 2 L-PET bottles), testing hydraulic retention times (HRT) of 18 and 24 h. Samples were exposed to an average solar radiation intensity of 518 W/m2. The results obtained indicate that the SODIS system has potential for total coliforms and E. coli inactivation in the pre-treated greywater, reaching 2.1 log units E. coli inactivation in batch experiments for low turbidity samples (21 NTU), and > 2 log units inactivation of total coliforms (and E. coli, when present) for the 24 h HRT-continuous prototype. The continuous flow prototype needs more testing and structural improvements to cope with the difficulties posed by algae growth, as they complicate maintaining conditions of constant flow and make frequent maintenance inevitable.

  17. Flow and thermal behavior of the top surface flux/powder layers in continuous casting molds

    Science.gov (United States)

    McDavid, R. M.; Thomas, B. G.

    1996-08-01

    Steady-state finite-element models have been formulated to investigate the coupled fluid flow and thermal behavior of the top-surface flux layers in continuous casting of steel slabs. The three-dimensional (3-D) FIDAP model includes the shear stresses imposed on the flux/steel interface by flow velocities calculated in the molten steel pool. It also includes different temperature-dependent powder properties for solidification and melting. Good agreement between the 3-D model and experimental measurements was obtained. The shear forces, imposed by the steel surface motion toward the submerged entry nozzle (SEN), create a large recirculation zone in the liquid flux pool. Its depth increases with increasing casting speed, increasing liquid flux conductivity, and decreasing flux viscosity. For typical conditions, this zone contains almost 4 kg of flux, which contributes to an average residence time of about 2 minutes. Additionally, because the shear forces produced by the narrowface consumption and the steel flow oppose each other, the flow in the liquid flux layer separates at a location centered 200 mm from the narrowface wall. This flow separation depletes the liquid flux pool at this location and may contribute to generically poor feeding of the mold-strand gap there. As a further consequence, a relatively cold spot develops at the wideface mold wall near the separation point. This nonuniformity in the temperature distribution may result in nonuniform heat removal, and possibly nonuniform initial shell growth in the meniscus region along the wideface off-corner region. In this way, potential steel quality problems may be linked to flow in the liquid flux pool.

  18. On-line monitoring of continuous flow chemical synthesis using a portable, small footprint mass spectrometer.

    Science.gov (United States)

    Bristow, Tony W T; Ray, Andrew D; O'Kearney-McMullan, Anne; Lim, Louise; McCullough, Bryan; Zammataro, Alessio

    2014-10-01

    For on-line monitoring of chemical reactions (batch or continuous flow), mass spectrometry (MS) can provide data to (1) determine the fate of starting materials and reagents, (2) confirm the presence of the desired product, (3) identify intermediates and impurities, (4) determine steady state conditions and point of completion, and (5) speed up process optimization. Recent developments in small footprint atmospheric pressure ionization portable mass spectrometers further enable this coupling, as the mass spectrometer can be easily positioned with the reaction system to be studied. A major issue for this combination is the transfer of a sample that is representative of the reaction and also compatible with the mass spectrometer. This is particularly challenging as high concentrations of reagents and products can be encountered in organic synthesis. The application of a portable mass spectrometer for on-line characterization of flow chemical synthesis has been evaluated by coupling a Microsaic 4000 MiD to the Future Chemistry Flow Start EVO chemistry system. Specifically, the Hofmann rearrangement has been studied using the on-line mass spectrometry approach. Sample transfer from the flow reactor is achieved using a mass rate attenuator (MRA) and a sampling make-up flow from a high pressure pump. This enables the appropriate sample dilution, transfer, and preparation for electrospray ionization. The capability of this approach to provide process understanding is described using an industrial pharmaceutical process that is currently under development. The effect of a number of key experimental parameters, such as the composition of the sampling make-up flow and the dilution factor on the mass spectrometry data, is also discussed. PMID:25106707

  19. Comparison of different Methods to model Transient Turbulent Magnetohydrodynamic Flow in Continuous Casting Molds

    Science.gov (United States)

    Kratzsch, C.; Asad, A.; Schwarze, R.

    2016-07-01

    Modeling of the processes in the continuous casting mold engaged many scientists once the computer-technology was able to accomplish that task. Despite that, CFD modeling of the fluid flow is still challenging. The methods allow deeper and deeper inside views into transient flow processes. Mostly two kinds of methods are applied for this purpose. URANS simulations are used for a coarse overview of the transient behavior on scales determined by the big rollers inside the mold. Besides, LES were done to study the processes on smaller scales. Unfortunately, the effort to set up a LES is orders of magnitude higher in time and space compared to URANS. Often, the flow determining processes take place in small areas inside the flow domain. Hence, scale resolving methods (SRS) came up, which resolve the turbulence in some amount in these regions, whereas they go back to URANS in the regions of less importance. It becomes more complex when dealing with magnetic fields in terms of EMBr devices. The impact of electro magnetically forces changes the flow structure remarkably. Many important effects occur, e.g. MHD turbulence, which are attributable to processes on large turbulent scales. To understand the underlying phenomena in detail, SRS allows a good inside view by resolving these processes partially. This study compares two of these methods, namely the Scale Adaptive Simulation (SAS) and the Delayed Detached Eddy Simulation (DDES), with respect to rendition of the results known from experiments and URANS simulation. The results show, that the SAS as well as the DDES are able to deliver good results with higher mesh resolutions in important regions in the flow domain

  20. ET-AAS determination of aluminium in dialysis concentrates after continuous flow solvent extraction.

    Science.gov (United States)

    Komárek, J; Cervenka, R; Růzicka, T; Kubán, V

    2007-11-01

    Conditions of a continuous flow extraction (CFE) of aluminium acetylacetonate in acetylacetone and aluminium 8-hydroxyquinolinate into methylisobutylketone (lengths of reaction and extraction coils, flow rates of aqueous and organic phases and their flow rate ratio, pH of aqueous phase, lengths of coils for transport of aqueous and organic phases and effect of salts) were studied. The analytical signal of the aluminium chelates present in the organic phase was measured at 309.3 nm using atomic absorption spectrometry with electrothermal atomization (ET-AAS) at the flow rate ratio F aq/F org=3 for aqueous and organic phases. The five points calibration curves were linear (R2 0.9973 and 0.9987) up to 21 microgl(-1) Al with the limits of detection of 0.3 microgl(-1) and the recovery 100+/-2% and precision of 3% at 2-10-fold dilution of the dialysis concentrates. The acetylacetonate method was applied to the determination of aluminium in real dialysis concentrates. Aluminium in concentrations 5-6 microgl(-1) (R.S.D.s 5-10% in real samples) were found and the results were in the very good agreement with those obtained by an ET-AAS using preconcentration of Al(III) on a Spheron-Salicyl chelating sorbent (absolute and relative differences were under 0.4 microgl(-1) and 8.2%, respectively). PMID:17897803

  1. Accelerated gas-liquid visible light photoredox catalysis with continuous-flow photochemical microreactors.

    Science.gov (United States)

    Straathof, Natan J W; Su, Yuanhai; Hessel, Volker; Noël, Timothy

    2016-01-01

    In this protocol, we describe the construction and use of an operationally simple photochemical microreactor for gas-liquid photoredox catalysis using visible light. The general procedure includes details on how to set up the microreactor appropriately with inlets for gaseous reagents and organic starting materials, and it includes examples of how to use it to achieve continuous-flow preparation of disulfides or trifluoromethylated heterocycles and thiols. The reported photomicroreactors are modular, inexpensive and can be prepared rapidly from commercially available parts within 1 h even by nonspecialists. Interestingly, typical reaction times of gas-liquid visible light photocatalytic reactions performed in microflow are lower (in the minute range) than comparable reactions performed as a batch process (in the hour range). This can be attributed to the improved irradiation efficiency of the reaction mixture and the enhanced gas-liquid mass transfer in the segmented gas-liquid flow regime.

  2. Accelerated gas-liquid visible light photoredox catalysis with continuous-flow photochemical microreactors.

    Science.gov (United States)

    Straathof, Natan J W; Su, Yuanhai; Hessel, Volker; Noël, Timothy

    2016-01-01

    In this protocol, we describe the construction and use of an operationally simple photochemical microreactor for gas-liquid photoredox catalysis using visible light. The general procedure includes details on how to set up the microreactor appropriately with inlets for gaseous reagents and organic starting materials, and it includes examples of how to use it to achieve continuous-flow preparation of disulfides or trifluoromethylated heterocycles and thiols. The reported photomicroreactors are modular, inexpensive and can be prepared rapidly from commercially available parts within 1 h even by nonspecialists. Interestingly, typical reaction times of gas-liquid visible light photocatalytic reactions performed in microflow are lower (in the minute range) than comparable reactions performed as a batch process (in the hour range). This can be attributed to the improved irradiation efficiency of the reaction mixture and the enhanced gas-liquid mass transfer in the segmented gas-liquid flow regime. PMID:26633128

  3. Continuous-flow stirred-tank reactor 20-L demonstration test: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lee, D.D.; Collins, J.L.

    2000-02-01

    One of the proposed methods of removing the cesium, strontium, and transuranics from the radioactive waste storage tanks at Savannah River is the small-tank tetraphenylborate (TPB) precipitation process. A two-reactor-in-series (15-L working volume each) continuous-flow stirred-tank reactor (CSTR) system was designed, constructed, and installed in a hot cell to test the Savannah River process. The system also includes two cross-flow filtration systems to concentrate and wash the slurry produced in the process, which contains the bulk of radioactivity from the supernatant processed through the system. Installation, operational readiness reviews, and system preparation and testing were completed. The first test using the filtration systems, two CSTRs, and the slurry concentration system was conducted over a 61-h period with design removal of Cs, Sr, and U achieved. With the successful completion of Test 1a, the following tests, 1b and 1c, were not required.

  4. Process Design of Continuous-Flow Pervaporation Separa tion for Alcohol Dehydration

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The separation characteristics of the PVA-CS (polyvinyl alcohol-chitosan) blended composite membrane for dehydration of ethanol-water mixture are examined. The relationships of flux and separation factor with the feed concentration and operation temperature are established. Using this correlated equation, the continuous-flow pervaporation process about 500 kilolitres/year dehydrated ethanol is designed. The numbers of stage and reheater are calculated by stage-by-stage method for two kinds of cascades: one with equal membrane area and the other with 10℃C of temperature decrement per section. The results show that when the numbers of stage and reheater are the same, the cascade with 10℃C of temperature decrement has more advantages than that with equal membrane area. The influences of feed concentration and flow rate on the numbers of stage and reheater in the cascades are discnssed.

  5. Rapid identification of Yersinia pestis and Brucella melitensis by chip-based continuous flow PCR

    Science.gov (United States)

    Dietzsch, Michael; Hlawatsch, Nadine; Melzer, Falk; Tomaso, Herbert; Gärtner, Claudia; Neubauer, Heinrich

    2012-06-01

    To combat the threat of biological agents like Yersinia pestis and Brucella melitensis in bioterroristic scenarios requires fast, easy-to-use and safe identification systems. In this study we describe a system for rapid amplification of specific genetic markers for the identification of Yersinia pestis and Brucella melitensis. Using chip based PCR and continuous flow technology we were able to amplify the targets simultaneously with a 2-step reaction profile within 20 minutes. The subsequent analysis of amplified fragments by standard gel electrophoresis requires another 45 minutes. We were able to detect both pathogens within 75 minutes being much faster than most other nucleic acid amplification technologies.

  6. Optimization of High-Resolution Continuous Flow Analysis for Transient Climate Signals in Ice Cores

    DEFF Research Database (Denmark)

    Bigler, Matthias; Svensson, Anders; Kettner, Ernesto;

    2011-01-01

    Over the past two decades, continuous flow analysis (CFA) systems have been refined and widely used to measure aerosol constituents in polar and alpine ice cores in very high-depth resolution. Here we present a newly designed system consisting of sodium, ammonium, dust particles, and electrolytic...... a depth resolution in the ice of a few millimeters which is considerably better than other CFA systems. Thus, the new system can resolve ice strata down to 10 mm thickness and has the potential of identifying annual layers in both Greenland and Antarctic ice cores throughout the last glacial cycle....

  7. Comparison of Fourier transform and continuous wavelet transform to study echo-planar imaging flow maps

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez G, A.; Bowtell, R.; Mansfield, P. [Area de Procesamiento Digital de Senales e Imagenes Biomedicas. Universidad Autonoma Metropolitana Iztapalapa. Mexico D.F. 09340 Mexico (Mexico)

    1998-12-31

    Velocity maps were studied combining Doyle and Mansfield method (1986) with each of the following transforms: Fourier, window Fourier and wavelet (Mexican hat). Continuous wavelet transform was compared against the two Fourier transform to determine which technique is best suited to study blood maps generated by Half Fourier Echo-Planar Imaging. Coefficient images were calculated and plots of the pixel intensity variation are presented. Finally, contour maps are shown to visualize the behavior of the blood flow in the cardiac chambers for the wavelet technique. (Author)

  8. Mechanistic insights into the oxidative dehydrogenation of amines to nitriles in continuous flow

    DEFF Research Database (Denmark)

    Corker, Emily C.; Ruiz-Martínez, Javier; Riisager, Anders;

    2015-01-01

    The oxidative dehydrogenation of various aliphatic amines to their corresponding nitrile compounds using RuO2/Al2O3 catalysts in air was successfully applied to a continuous flow reaction. Conversions of amines (up to >99%) and yields of nitriles (up to 77%) varied depending on reaction conditions...... and the amine utilised. The presence of water was found to be important for the activity and stability of the RuO2/Al2O3 catalyst. The Hammett relationship and in situ infrared spectroscopy were applied to divulge details about the catalytic mechanism of the oxidative dehydrogenation of amines over Ru...

  9. MHD visco elastic boundary layer flow with free convention past a continuous moving surface

    International Nuclear Information System (INIS)

    The behaviour of free convective boundary layer flow of an electrically conducting, viscoelastic, incompressible fluid over a continuously moving flat surface in presence of uniform magnetic field with constant suction is studied in this section. A uniform magnetic field is assumed to be applied perpendicular to the moving flat surface. The velocity and temperature field are obtained. The effect of R (small Reynold's number), M (Hartmann number), G (Grashoff number) and Ko (visco-elastic parameter) on velocity field and temperature field are discussed with the help of graphs. (author)

  10. Nitrification and denitrifying phosphorus removal in an upright continuous flow reactor.

    Science.gov (United States)

    Reza, Maryam; Alvarez Cuenca, Manuel

    2016-01-01

    Simultaneous nitrification and denitrifying phosphorus removal was achieved in a single-sludge continuous flow bioreactor. The upright bioreactor was aligned with a biomass fermenter (BF) and operated continuously for over 350 days. This study revealed that unknown bacteria of the Saprospiraceae class may have been responsible for the successful nutrient removal in this bioreactor. The successive anoxic-aerobic stages of the bioreactor with upright alignment along with a 60 L BF created a unique ecosystem for the growth of nitrifier, denitrifiers, phosphorus accumulating organisms and denitrifying phosphorus accumulating organisms. Furthermore, total nitrogen to chemical oxygen demand (COD) ratio and total phosphorus to COD ratio of 0.6 and 0.034, respectively, confirmed the comparative advantages of this advanced nutrient removal process relative to both sequencing batch reactors and activated sludge processes. The process yielded 95% nitrogen removal and over 90% phosphorus removal efficiencies. PMID:27148710

  11. Process Development for Hydrothermal Liquefaction of Algae Feedstocks in a Continuous-Flow Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, Douglas C.; Hart, Todd R.; Schmidt, Andrew J.; Neuenschwander, Gary G.; Rotness, Leslie J.; Olarte, Mariefel V.; Zacher, Alan H.; Albrecht, Karl O.; Hallen, Richard T.; Holladay, Johnathan E.

    2013-10-01

    Wet algae slurries can be converted into an upgradeable biocrude by hydrothermal liquefaction (HTL). High levels of carbon conversion to gravity-separable biocrude product were accomplished at relatively low temperature (350 °C) in a continuous-flow, pressurized (sub-critical liquid water) environment (20 MPa). As opposed to earlier work in batch reactors reported by others, direct oil recovery was achieved without the use of a solvent and biomass trace components were removed by processing steps so that they did not cause process difficulties. High conversions were obtained even with high slurry concentrations of up to 35 wt% of dry solids. Catalytic hydrotreating was effectively applied for hydrodeoxygenation, hydrodenitrogenation, and hydrodesulfurization of the biocrude to form liquid hydrocarbon fuel. Catalytic hydrothermal gasification was effectively applied for HTL byproduct water cleanup and fuel gas production from water soluble organics, allowing the water to be considered for recycle of nutrients to the algae growth ponds. As a result, high conversion of algae to liquid hydrocarbon and gas products was found with low levels of organic contamination in the byproduct water. All three process steps were accomplished in bench-scale, continuous-flow reactor systems such that design data for process scale-up was generated.

  12. A disposable, continuous-flow polymerase chain reaction device: design, fabrication and evaluation.

    Science.gov (United States)

    Ragsdale, Victoria; Li, Huizhong; Sant, Himanshu; Ameel, Tim; Gale, Bruce K

    2016-08-01

    Polymerase Chain Reaction (PCR) is used to amplify a specific segment of DNA through a thermal cycling protocol. The PCR industry is shifting its focus away from macro-scale systems and towards micro-scale devices because: micro-scale sample sizes require less blood from patients, total reaction times are on the order of minutes opposed to hours, and there are cost advantages as many microfluidic devices are manufactured from inexpensive polymers. Some of the fastest PCR devices use continuous flow, but they have all been built of silicon or glass to allow sufficient heat transfer. This article presents a disposable polycarbonate (PC) device that is capable of achieving real-time, continuous flow PCR in a completely disposable polymer device in less than 13 minutes by thermally cycling the sample through an established temperature gradient in a serpentine channel. The desired temperature gradient was determined through simulations and validated by experiments which showed that PCR was achieved. Practical demonstration included amplification of foot-and-mouth disease virus (FMDV) derived cDNA. PMID:27393216

  13. Continued development of the Nimbus/University of Pittsburgh (UOP) axial flow left ventricular assist system.

    Science.gov (United States)

    Thomas, D C; Butler, K C; Taylor, L P; Le Blanc, P; Griffith, B P; Kormos, R L; Borovetz, H S; Litwak, P; Kameneva, M V; Choi, S; Burgreen, G W; Wagner, W R; Wu, Z; Antaki, J F

    1997-01-01

    Nimbus and the University of Pittsburgh (UOP) have continued the development of a totally implanted axial flow blood pump under the National Institutes of Health (NIH) Innovative Ventricular Assist System (IVAS) program. This 62 cc device has an overall length of 84 mm and an outer diameter of 34.5 mm. The inner diameter of the blood pump is 12 mm. It is being designed to be a totally implanted permanent device. A key achievement during the past year was the completion of the Model 2 pump design. Ten of these pumps have been fabricated and are being used to conduct in vitro and in vivo experiments to evaluate the performance of different materials and hydraulic components. Efforts for optimizing the closed loop speed control have continued using mathematical modeling, computer simulations, and in vitro and in vivo testing. New hydraulic blade designs have been tested using computational fluid dynamics (CFD) and flow visualization. A second generation motor was designed with improved efficiency. To support the new motor, a new motor controller fabricated as a surface mount PC board has been completed. The program is now operating under a formal QA system.

  14. Continuous surface force based lattice Boltzmann equation method for simulating thermocapillary flow

    Science.gov (United States)

    Zheng, Lin; Zheng, Song; Zhai, Qinglan

    2016-02-01

    In this paper, we extend a lattice Boltzmann equation (LBE) with continuous surface force (CSF) to simulate thermocapillary flows. The model is designed on our previous CSF LBE for athermal two phase flow, in which the interfacial tension forces and the Marangoni stresses as the results of the interface interactions between different phases are described by a conception of CSF. In this model, the sharp interfaces between different phases are separated by a narrow transition layers, and the kinetics and morphology evolution of phase separation would be characterized by an order parameter via Cahn-Hilliard equation which is solved in the frame work of LBE. The scalar convection-diffusion equation for temperature field is resolved by thermal LBE. The models are validated by thermal two layered Poiseuille flow, and two superimposed planar fluids at negligibly small Reynolds and Marangoni numbers for the thermocapillary driven convection, which have analytical solutions for the velocity and temperature. Then thermocapillary migration of two/three dimensional deformable droplet are simulated. Numerical results show that the predictions of present LBE agreed with the analytical solution/other numerical results.

  15. On Grain Dynamics in Debris Discs: Continuous Outward Flows and Embedded Planets

    CERN Document Server

    Jiang, Ing-Guey

    2009-01-01

    This study employed grain dynamic models to examine the density distribution of debris discs, and discussed the effects of the collisional time-intervals of asteroidal bodies, the maximum grain sizes, and the chemical compositions of the dust grains of the models, in order to find out whether a steady out-moving flow with an 1/R profile could be formed. The results showed that a model with new grains every 100 years, a smaller maximum grain size, and a composition C400 has the best fit to the 1/R profile because: (1) the grains have larger values of beta on average,therefore, they can be blown out easily; (2) the new grains are generated frequently enough to replace those have been blown out. With the above two conditions, some other models can have a steady out-moving flow with an approximate 1/R profile. However, those models in which new grains are generated every 1000 years have density distributions far from the profile of a continuous out-moving flow. Moreover, the analysis on the signatures of planets ...

  16. Practical Strategies for Stable Operation of HFF-QCM in Continuous Air Flow

    Directory of Open Access Journals (Sweden)

    Siegfried R. Waldvogel

    2013-09-01

    Full Text Available Currently there are a few fields of application using quartz crystal microbalances (QCM. Because of environmental conditions and insufficient resolution of the microbalance, chemical sensing of volatile organic compounds in an open system was as yet not possible. In this study we present strategies on how to use 195 MHz fundamental quartz resonators for a mobile sensor platform to detect airborne analytes. Commonly the use of devices with a resonant frequency of about 10 MHz is standard. By increasing the frequency to 195 MHz the frequency shift increases by a factor of almost 400. Unfortunately, such kinds of quartz crystals tend to exhibit some challenges to obtain a reasonable signal-to-noise ratio. It was possible to reduce the noise in frequency in a continuous air flow of 7.5 m/s to 0.4 Hz [i.e., σ(τ = 2 × 10−9] by elucidating the major source of noise. The air flow in the vicinity of the quartz was analyzed to reduce turbulences. Furthermore, we found a dependency between the acceleration sensitivity and mechanical stress induced by an internal thermal gradient. By reducing this gradient, we achieved reduction of the sensitivity to acceleration by more than one decade. Hence, the resulting sensor is more robust to environmental conditions such as temperature, acceleration and air flow.

  17. Practical strategies for stable operation of HFF-QCM in continuous air flow.

    Science.gov (United States)

    Wessels, Alexander; Klöckner, Bernhard; Siering, Carsten; Waldvogel, Siegfried R

    2013-09-09

    Currently there are a few fields of application using quartz crystal microbalances (QCM). Because of environmental conditions and insufficient resolution of the microbalance, chemical sensing of volatile organic compounds in an open system was as yet not possible. In this study we present strategies on how to use 195 MHz fundamental quartz resonators for a mobile sensor platform to detect airborne analytes. Commonly the use of devices with a resonant frequency of about 10 MHz is standard. By increasing the frequency to 195 MHz the frequency shift increases by a factor of almost 400. Unfortunately, such kinds of quartz crystals tend to exhibit some challenges to obtain a reasonable signal-to-noise ratio. It was possible to reduce the noise in frequency in a continuous air flow of 7.5 m/s to 0.4 Hz [i.e., σ(τ) = 2 × 10-9] by elucidating the major source of noise. The air flow in the vicinity of the quartz was analyzed to reduce turbulences. Furthermore, we found a dependency between the acceleration sensitivity and mechanical stress induced by an internal thermal gradient. By reducing this gradient, we achieved reduction of the sensitivity to acceleration by more than one decade. Hence, the resulting sensor is more robust to environmental conditions such as temperature, acceleration and air flow.

  18. Modeling on Fluid Flow and Inclusion Motion in Centrifugal Continuous Casting Strands

    Science.gov (United States)

    Wang, Qiangqiang; Zhang, Lifeng; Sridhar, Seetharaman

    2016-08-01

    During the centrifugal continuous casting process, unreasonable casting parameters can cause violent level fluctuation, serious gas entrainment, and formation of frozen shell pieces at the meniscus. Thus, in the current study, a three-dimensional multiphase turbulent model was established to study the transport phenomena during centrifugal continuous casting process. The effects of nozzle position, casting and rotational speed on the flow pattern, centrifugal force acting on the molten steel, level fluctuation, gas entrainment, shear stress on mold wall, and motion of inclusions during centrifugal continuous casting process were investigated. Volume of Fluid model was used to simulate the molten steel-air two-phase. The level fluctuation and the gas entrainment during casting were calculated by user-developed subroutines. The trajectory of inclusions in the rotating system was calculated using the Lagrangian approach. The results show that during centrifugal continuous casting, a large amount of gas was entrained into the molten steel, and broken into bubbles of various sizes. The greater the distance to the mold wall, the smaller the centrifugal force. Rotation speed had the most important influence on the centrifugal force distribution at the side region. Angular moving angle of the nozzle with 8° and keeping the rotation speed with 60 revolutions per minute can somehow stabilize the level fluctuation. The increase of angular angle of nozzle from 8 to 18 deg and rotation speed from 40 to 80 revolutions per minute favored to decrease the total volume of entrained bubbles, while the increase of distance of nozzle moving left and casting speed had reverse effects. The trajectories of inclusions in the mold were irregular, and then rotated along the strand length. After penetrating a certain distance, the inclusions gradually moved to the center of billet and gathered there. More work, such as the heat transfer, the solidification, and the inclusions entrapment

  19. Quantitative Assessment of Mass Flow Boundaries in Continuous Twin-screw Granulation.

    Science.gov (United States)

    Schmidt, Adrian; de Waard, Hans; Moll, Klaus-Peter; Krumme, Markus; Kleinebudde, Peter

    2016-01-01

    In pharmaceutical manufacturing, there is an increasing interest in continuous manufacturing. As an example for fast continuous processes in general of considerable complexity, this study was focussed on improving the understanding of twin-screw wet granulation. The impact of the liquid-to-solid (L/S) mass flow ratio on product quality (granules) as well as on downstream process operations (tableting) was investigated in detail. Initially two methods were used to define L/S ratio boundaries for the granulation regime in twin-screw wet granulation. It was shown that the first method, which is based on measuring the wet granule mass flow variation, can be used to define the upper L/S ratio boundary of the granulation regime. The second method, based on measuring the granule size distribution, can be used to define the lower L/S ratio boundary of the regime. Using these methods, the granulation regime for different formulations could be established. This information was then used to show that the formulation could be optimised such that the process is more robust (i.e. wider L/S ratio boundaries for the granulation regime). Also it could be used to optimise the formulation considering further downstream processing such as drying (using as little water as possible to reduce drying efforts) or tableting (obtain granules with optimised tableting properties). Preferably, the process should be performed close to the lower L/S ratio boundary of the granulation regime. In summary, these tools enabled the quantitative establishment of granulation regime boundaries in a twin-screw wet granulation process and can be used to optimise formulation and to create a robust process. Analogies to other continuous processes in completely different applications can be conceived. PMID:27646540

  20. Thermal performance of shallow solar pond under open cycle continuous flow heating mode for heat extraction

    Energy Technology Data Exchange (ETDEWEB)

    El-Sebaii, A.A. [Department of Physics, Faculty of Science, Tanta University, Tanta 31527 (Egypt)]. E-mail: aasebaii@yahoo.com; Aboul-Enein, S. [Department of Physics, Faculty of Science, Tanta University, Tanta 31527 (Egypt); Ramadan, M.R.I. [Department of Physics, Faculty of Science, Tanta University, Tanta 31527 (Egypt); Khallaf, A.M. [Department of Physics, Faculty of Science, Tanta University, Tanta 31527 (Egypt)

    2006-05-15

    The thermal performance of a shallow solar pond (SSP) under an open cycle continuous flow heating mode for heat extraction has been investigated. A serpentine heat exchanger (HE), either welded to the absorber plate or immersed in the pond water, has been used for extracting the heat. Suitable computer programs have been developed based on analytical solutions of the energy balance equations for the various elements of the SSP in the presence of the HE. Numerical calculations have been performed to study the effect of different operational and configurational parameters on the pond performance. In order to improve the pond performance, optimization of the various dimensions of the pond with the HE has been performed. The effects of the design parameters of the HE's tube, i.e. length L{sub he}, diameter D and mass flow rate m-bar {sub f} of the fluid flowing through the HE, on the pond performance have been investigated. The outlet temperature of the HE's fluid T{sub fo} is found to increase with increase of the HE length L{sub he}, and it decreases with increase of the mass flow rate of the HE's fluid m-bar {sub f} up to typical values for these parameters. Typical values for L{sub he} and m-bar {sub f} are found to be 4m and 0.004kg/s beyond which the change in T{sub fo} becomes insignificant. Experiments have been performed for the pond under different operational conditions with a HE welded to the absorber plate. To validate the proposed mathematical models, comparisons between experimental and theoretical results have been performed. Good agreement has been achieved.

  1. Numerical study on three-dimensional flow field of continuously rotating detonation in a toroidal chamber

    Institute of Scientific and Technical Information of China (English)

    Xu-Dong Zhang; Bao-Chun Fan; Ming-Yue Gui; Zhen-Hua Pan; Gang Dong

    2012-01-01

    Gaseous detonation propagating in a toroidal chamber was numerically studied for hydrogen/oxygen/nitrogen mixtures.The numerical method used is based on the three-dimensional Euler equations with detailed finiterate chemistry.The results show that the calculated streak picture is in qualitative agreement with the picture recorded by a high speed streak camera from published literature.The three-dimensional flow field induced by a continuously rotating detonation was visualized and distinctive features of the rotating detonations were clearly depicted.Owing to the unconfined character of detonation wavelet,a deficit of detonation parameters was observed.Due to the effects of wall geometries,the strength of the outside detonation front is stronger than that of the inside portion.The detonation thus propagates with a constant circular velocity.Numerical simulation also shows three-dimensional rotating detonation structures,which display specific feature of the detonationshock combined wave. Discrete burning gas pockets are formed due to instability of the discontinuity.It is believed that the present study could give an insight into the interesting properties of the continuously rotating detonation,and is thus beneficial to the design of continuous detonation propulsion systems.

  2. The Bi-Directional Prediction of Carbon Fiber Production Using a Combination of Improved Particle Swarm Optimization and Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Chuncai Xiao

    2014-12-01

    Full Text Available This paper creates a bi-directional prediction model to predict the performance of carbon fiber and the productive parameters based on a support vector machine (SVM and improved particle swarm optimization (IPSO algorithm (SVM-IPSO. In the SVM, it is crucial to select the parameters that have an important impact on the performance of prediction. The IPSO is proposed to optimize them, and then the SVM-IPSO model is applied to the bi-directional prediction of carbon fiber production. The predictive accuracy of SVM is mainly dependent on its parameters, and IPSO is thus exploited to seek the optimal parameters for SVM in order to improve its prediction capability. Inspired by a cell communication mechanism, we propose IPSO by incorporating information of the global best solution into the search strategy to improve exploitation, and we employ IPSO to establish the bi-directional prediction model: in the direction of the forward prediction, we consider productive parameters as input and property indexes as output; in the direction of the backward prediction, we consider property indexes as input and productive parameters as output, and in this case, the model becomes a scheme design for novel style carbon fibers. The results from a set of the experimental data show that the proposed model can outperform the radial basis function neural network (RNN, the basic particle swarm optimization (PSO method and the hybrid approach of genetic algorithm and improved particle swarm optimization (GA-IPSO method in most of the experiments. In other words, simulation results demonstrate the effectiveness and advantages of the SVM-IPSO model in dealing with the problem of forecasting.

  3. An easy and economical in vitro method for the formation of Candida albicans biofilms under continuous conditions of flow.

    Science.gov (United States)

    Uppuluri, Priya; Lopez-Ribot, Jose L

    2010-01-01

    Candida albicans can develop biofilms on medical devices and these biofilms are most often nourished by a continuous flow of body fluids and subjected to shear stress forces. While many C. albicans biofilm studies have been carried out using in vitro static models, more limited information is available for biofilms developed under conditions of flow. We have previously described a simple flow biofilm model (SFB) for the development of C. albicans biofilms under conditions of continuous media flow. Here, we recount in detail from a methodological perspective, this model that can be assembled easily using materials commonly available in most microbiological laboratories. The entire procedure takes approximately two days to complete. Biofilms developed using this system are robust, and particularly suitable for studies requiring large amounts of biofilm cells for downstream analyses. This methodology simplifies biofilm formation under continuous replenishment of nutrients. Moreover, this technique mimics in vivo flow conditions, thereby making it physiologically more relevant than the currently dominant static models.

  4. The NOFLO trial: low-flow nasal prongs therapy in weaning nasal continuous positive airway pressure in preterm infants.

    LENUS (Irish Health Repository)

    O'Donnell, Sinéad M

    2013-07-01

    To determine if low-flow nasal prongs therapy with room air, compared with no treatment, facilitates weaning from nasal continuous positive airway pressure (NCPAP) in very low birth weight (VLBW, birth weight <1500 g) infants.

  5. Method 349.0 Determination of Ammonia in Estuarine and Coastal Waters by Gas Segmented Continuous Flow Colorimetric Analysis

    Science.gov (United States)

    This method provides a procedure for the determination of ammonia in estuarine and coastal waters. The method is based upon the indophenol reaction,1-5 here adapted to automated gas-segmented continuous flow analysis.

  6. The enhancement effect of pp38 gene product on the activity of its upstream bi-directional promoter in Marek's disease virus

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    There was a bi-directional promoter between gene 38 kd phosphorylated protein (pp38) gene and 1.8-kb mRNA transcript gene family in the genome of Marek's disease virus (MDV). In this study, enhanced green fluorescence protein (EGFP) reporter plamids, pP(pp38)-EGFP and pP(1.8- kb)-EGFP, were constructed under this bi-directional promoter in two directions. The two plasmids were transfected into uninfected chicken embryo fibroblast (CEF), MDV clone rMd5 infected CEF (rMd5-CEF) and pp38-deleted derivative rMd5Δpp38 infected CEF (rMd5Δpp38-CEF) respectively. Transfection analysis showed that EGFP was only expressed in rMd5-CEF, and no EGFP could be detected in uninfected CEF or rMd5Δpp38-CEF, implying that pp38 was a factor influencing the activity of the promoter. The pp38-expressing recombinant plasmid pcDNA-pp38 was constructed to co- transfect CEF or rMd5Δpp38-CEF with pP(pp38)-EGFP or pP(1.8-kb)-EGFP. In this case, EGFP could be detected only in rMd5Δpp38-CEF but still not in uninfected CEF, implying that pp38 needs other protein(s) to work together for the complete trans-acting activity. Another MDV gene, 24 kd phosphorylated protein pp24 gene was cloned into pcDNA3.1 as a pp24-expressing recombinant plasmid pcDNA-pp24. When uninfected CEF was co-transfected with pcDNA-pp38, pcDNA-pp24 and EGFP expressing plasmids pP(pp38)-EGFP or pP(1.8-kb)-EGFP, the EGFP could be detected. These results indicated that pp38 and pp24 could enhance the activity of the promoter when they worked together. DNA mobility shift assay showed that pp38 would bind to the bi-directional promoter with the co-existing of pp24, although neither of them alone influenced mobility of the promoter DNA. All the above suggested that MDV pp38 could transactivate the bi-directional promoter when combined with pp24. The results also indicated that the activity of the promoter in the direction of 1.8-kb mRNA was significantly stronger than that of pp38 direction.

  7. Analysis and Design of Bi-Directional DC-DC Converter in the Extended Run Time DC UPS System Based on Fuel Cell and Supercapacitor

    DEFF Research Database (Denmark)

    Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.;

    2009-01-01

    Abstract-In this paper, an extended run time DC UPS system structure with fuel cell and supercapacitor is investigated. A wide input range bi-directional dc-dc converter is described along with the phase-shift modulation scheme and phase-shift with duty cycle control, in different modes...... input voltage combined with load current feedback using PI controller with anti-windup scheme to realize closed-loop control of the whole system, and verify the feasibility of the control scheme proposed by simulation. A 1kW prototype controlled by TMS320F2808 DSP is implemented and tested. Experimental...

  8. Simulation analysis of one-stage C+L-band erbium-doped fiber ASE source with double-pass bi-directional pumping configuration

    Institute of Scientific and Technical Information of China (English)

    Wencai Huang(黄文财); Hai Ming(明海)

    2004-01-01

    A new technique to generate a C+L-band flat amplified spontaneous emission (ASE) source in one-stage erbium-doped fiber (EDF) using bi-directional pumping configuration is analyzed. The simulation results show that the key point of obtaining flat C+L-band ASE spectrum in one-stage EDF is using a laser diode operated at 980 nm as backward pump source. ASE source with nearly 80-nm bandwidth can be obtained by means of selecting suitable fiber length and properly adjusting the ratio of forward to backward pump power.

  9. Bacterial communities in batch and continuous-flow wetlands treating the herbicide S-metolachlor

    Energy Technology Data Exchange (ETDEWEB)

    Elsayed, O.F. [Laboratory of Hydrology and Geochemistry of Strasbourg (LHyGeS), UMR 7517 University of Strasbourg/ENGEES/CNRS (France); Génétique Moléculaire, Génomique, Microbiologie (GMGM), UMR 7156 University of Strasbourg/CNRS (France); Maillard, E. [Laboratory of Hydrology and Geochemistry of Strasbourg (LHyGeS), UMR 7517 University of Strasbourg/ENGEES/CNRS (France); Vuilleumier, S. [Génétique Moléculaire, Génomique, Microbiologie (GMGM), UMR 7156 University of Strasbourg/CNRS (France); Imfeld, G., E-mail: imfeld@unistra.fr [Laboratory of Hydrology and Geochemistry of Strasbourg (LHyGeS), UMR 7517 University of Strasbourg/ENGEES/CNRS (France)

    2014-11-15

    Knowledge of wetland bacterial communities in the context of pesticide contamination and hydrological regime is scarce. We investigated the bacterial composition in constructed wetlands receiving Mercantor Gold{sup ®} contaminated water (960 g L{sup −1} of the herbicide S-metolachlor, > 80% of the S-enantiomer) operated under continuous-flow or batch modes to evaluate the impact of the hydraulic regime. In the continuous-flow wetland, S-metolachlor mass removal was > 40%, whereas in the batch wetland, almost complete removal of S-metolachlor (93–97%) was observed. Detection of ethanesulfonic and oxanilic acid degradation products further indicated S-metolachlor biodegradation in the two wetlands. The dominant bacterial populations were characterised by terminal restriction fragment length polymorphism (T-RFLP) and 454 pyrosequencing. The bacterial profiles evolved during the first 35 days of the experiment, starting from a composition similar to that of inlet water, with the use of nitrate and to a lesser extent sulphate and manganese as terminal electron acceptors for microbial metabolism. Proteobacteria were the most abundant phylum, with Beta-, Alpha- and Gammaproteobacteria representing 26%, 19% and 17% respectively of total bacterial abundance. Bacterial composition in wetland water changed gradually over time in continuous-flow wetland and more abruptly in the batch wetland. Differences in overall bacterial water structure in the two systems were modest but significant (p = 0.008), and S-metolachlor, nitrate, and total inorganic carbon concentrations correlated with changes in the bacterial profiles. Together, the results highlight that bacterial composition profiles and their dynamics may be used as bioindicators of herbicide exposure and hydraulic disturbances in wetland systems. - Highlights: • We evaluated the bacterial composition in wetlands treating S-metolachlor • Hydraulic regime impacted biogeochemical processes and S-metolachlor removal

  10. Square wave adsorptive stripping voltammetry of nickel and cobalt at wall-jet electrodes in continuous flow

    OpenAIRE

    Brett, Christopher M. A.; Garcia, M. Beatriz Quinaz; Lima, José L.F.C.

    1996-01-01

    Square wave adsorptive stripping voltammetry (SWAdSV) of nickel and cobalt at wall-jet electrodes in a continuous flow system has been evaluated. Characteristics and advantages relative to differential pulse adsorptive stripping voltammetry (DPAdSV) in continuous flow systems are explored. Under optimized experimental conditions, sensitivity is approximately a factor of ten higher than DPAdSV, and one-nanomolar detection limits are achieved. Solution deoxygenation is unnecessary and sample th...

  11. Selected low-flow frequency statistics for continuous-record streamgages in Georgia, 2013

    Science.gov (United States)

    Gotvald, Anthony J.

    2016-04-13

    This report presents the annual and monthly minimum 1- and 7-day average streamflows with the 10-year recurrence interval (1Q10 and 7Q10) for 197 continuous-record streamgages in Georgia. Streamgages used in the study included active and discontinued stations having a minimum of 10 complete climatic years of record as of September 30, 2013. The 1Q10 and 7Q10 flow statistics were computed for 85 streamgages on unregulated streams with minimal diversions upstream, 43 streamgages on regulated streams, and 69 streamgages known, or considered, to be affected by varying degrees of diversions upstream. Descriptive information for each of these streamgages, including the U.S. Geological Survey (USGS) station number, station name, latitude, longitude, county, drainage area, and period of record analyzed also is presented.Kendall’s tau nonparametric test was used to determine the statistical significance of trends in annual and monthly minimum 1-day and 7-day average flows for the 197 streamgages. Significant negative trends in the minimum annual 1-day and 7-day average streamflow were indicated for 77 of the 197 streamgages. Many of these significant negative trends are due to the period of record ending during one of the recent droughts in Georgia, particularly those streamgages with record through the 2013 water year. Long-term unregulated streamgages with 70 or more years of record indicate significant negative trends in the annual minimum 7-day average flow for central and southern Georgia. Watersheds for some of these streamgages have experienced minimal human impact, thus indicating that the significant negative trends observed in flows at the long-term streamgages may be influenced by changing climatological conditions. A Kendall-tau trend analysis of the annual air temperature and precipitation totals for Georgia indicated no significant trends. A comprehensive analysis of causes of the trends in annual and monthly minimum 1-day and 7-day average flows in central

  12. Optimum cadmium reactor designs for colorimetric determination of nitrate with flow injection and gas-segmented continuous flow analyzers

    International Nuclear Information System (INIS)

    Cadmium reactor types can be grouped into four categories: packed bed; filamentous; open tubular; and planar. Packed bed cadmium reactors, in the form of cadmium filings, granules, powder, or electrolytically precipitated needles packed into glass or polymeric tubes, are by far the most widely used for both FIA and CFA methods. Surprisingly, filamentous cadmium reactors, in the form of cadmium wire slipped into flexible polymeric tubing, have been reported for CFA applications only. Open tubular cadmium reactors, in the form of small diameter cadmium tubing coiled into a helix, have been fully characterized and described for CFA applications. A preliminary description of planar cadmium reactors, in the form of cadmium foil sandwiched between continuous flow dialyzer blocks has also been reported. In this presentation, each reactor type is evaluated in terms of cost, ease of use, reduction efficiency, and long-term stability. Factors that make some reactors more applicable to FIA than to CFA (or the reverse) are also discussed, and experimental data are presented

  13. Rapid Determination of Optimal Conditions in a Continuous Flow Reactor Using Process Analytical Technology

    Directory of Open Access Journals (Sweden)

    Michael F. Roberto

    2013-12-01

    Full Text Available Continuous flow reactors (CFRs are an emerging technology that offer several advantages over traditional batch synthesis methods, including more efficient mixing schemes, rapid heat transfer, and increased user safety. Of particular interest to the specialty chemical and pharmaceutical manufacturing industries is the significantly improved reliability and product reproducibility over time. CFR reproducibility can be attributed to the reactors achieving and maintaining a steady state once all physical and chemical conditions have stabilized. This work describes the implementation of a smart CFR with univariate physical and multivariate chemical monitoring that allows for rapid determination of steady state, requiring less than one minute. Additionally, the use of process analytical technology further enabled a significant reduction in the time and cost associated with offline validation methods. The technology implemented for this study is chemistry and hardware agnostic, making this approach a viable means of optimizing the conditions of any CFR.

  14. Continuous flow method for simultaneous determination of nitrate and ammonia in water

    Energy Technology Data Exchange (ETDEWEB)

    Aoki, T.; Uemura, S.; Munemori, M.

    1986-05-01

    A new continuous flow procedure is proposed for the simultaneous determination of nitrate and ammonia in water. Ammonia is fluorometrically determined with o-phthalaldehyde reagent, and nitrate is determined after reducing it to ammonia in alkaline medium by titanium-(III) chloride. The ammonia generated in alkaline sample solution is separated with a tubular microporous PTFE membrane. Nitrite stoichiometrically interferes with the present method but can be masked by sulfanilic acid. Detection limits (S/N = 3) for nitrate and ammonia were 1.8 x 10/sup -7/ and 1.8 x 10/sup -8/ M, respectively. Nitrate and ammonia in rivers were simultaneously determined with satisfactory results. 12 references, 3 figures, 4 tables.

  15. Accessing Stereochemically Rich Sultams via Microwave-Assisted, Continuous Flow Organic Synthesis (MACOS) Scale-out

    Science.gov (United States)

    Organ, Michael G.; Hanson, Paul R.; Rolfe, Alan; Samarakoon, Thiwanka B.; Ullah, Farman

    2011-01-01

    The generation of stereochemically-rich benzothiaoxazepine-1,1′-dioxides for enrichment of high-throughput screening collections is reported. Utilizing a microwave-assisted, continuous flow organic synthesis platform (MACOS), scale-out of core benzothiaoxazepine-1,1′-dioxide scaffolds has been achieved on multi-gram scale using an epoxide opening/SNAr cyclization protocol. Diversification of these sultam scaffolds was attained via a microwave-assisted intermolecular SNAr reaction with a variety of amines. Overall, a facile, 2-step protocol generated a collection of benzothiaoxazepine-1,1′-dioxides possessing stereochemical complexity in rapid fashion, where all 8 stereoisomers were accessed from commercially available starting materials. PMID:22116791

  16. Dielectrophoresis based continuous-flow nano sorter: fast quality control of gene vaccines.

    Science.gov (United States)

    Viefhues, Martina; Wegener, Sonja; Rischmüller, Anja; Schleef, Martin; Anselmetti, Dario

    2013-08-01

    We present a prototype nanofluidic device, developed for the continuous-flow dielectrophoretic (DEP) fractionation, purification, and quality control of sample suspensions for gene vaccine production. The device consists of a cross injector, two operation regions, and separate outlets where the analytes are collected. In each DEP operation region, an inhomogeneous electric field is generated at a channel spanning insulating ridge. The samples are driven by ac and dc voltages that generate a dielectrophoretic potential at the ridge as well as (linear) electrokinetics. Since the DEP potential differs at the two ridges, probes of three and more species can be iteratively fully fractionated. We demonstrate the fast and efficient separation of parental plasmid, miniplasmid, and minicircle DNA, where the latter is applicable as a gene vaccine. Since the present technique is virtually label-free, it offers a fast purification and in-process quality control with low consumption, in parallel, for the production of gene vaccines.

  17. Continuous Drip Flow System to Develop Biofilm of E. faecalis under Anaerobic Conditions

    Directory of Open Access Journals (Sweden)

    Ana Maria Gonzalez

    2014-01-01

    Full Text Available Purpose. To evaluate a structurally mature E. faecalis biofilm developed under anaerobic/dynamic conditions in an in vitro system. Methods. An experimental device was developed using a continuous drip flow system designed to develop biofilm under anaerobic conditions. The inoculum was replaced every 24 hours with a fresh growth medium for up to 10 days to feed the system. Gram staining was done every 24 hours to control the microorganism purity. Biofilms developed under the system were evaluated under the scanning electron microscope (SEM. Results. SEM micrographs demonstrated mushroom-shaped structures, corresponding to a mature E. faecalis biofilm. In the mature biofilm bacterial cells are totally encased in a polymeric extracellular matrix. Conclusions. The proposed in vitro system model provides an additional useful tool to study the biofilm concept in endodontic microbiology, allowing for a better understanding of persistent root canal infections.

  18. Assessing optimal fermentation type for bio-hydrogen production in continuous-flow acidogenic reactors.

    Science.gov (United States)

    Ren, N Q; Chua, H; Chan, S Y; Tsang, Y F; Wang, Y J; Sin, N

    2007-07-01

    In this study, the optimal fermentation type and the operating conditions of anaerobic process in continuous-flow acidogenic reactors was investigated for the maximization of bio-hydrogen production using mixed cultures. Butyric acid type fermentation occurred at pH>6, propionic acid type fermentation occurred at pH about 5.5 with E(h) (redox potential) >-278mV, and ethanol-type fermentation occurred at pHClostridium sp., Propionibacterium sp. and Bacteriodes sp., respectively. Ethanol fermentation was optimal type by comparing the operating stabilities and hydrogen production capacities between the fermentation types, which remained stable when the organic loading rate (OLR) reached the highest OLR at 86.1kgCOD/m(3)d. The maximum hydrogen production reached up to 14.99L/d.

  19. Simulation and design of a self-heating continuous-flow PCR chip

    Institute of Scientific and Technical Information of China (English)

    CHEN Wei-ping; TIAN Li; LI Ming-jiang; LIU Xiao-wei

    2007-01-01

    A novel continuous-flow PCR chip adopting self-heating, passive-cooling mode to realize the DNA fragments amplification was presented. Using the ANSYS finite element analysis, the temperature distribution of the chip is simulated and analyzed. The optimal size of the chip is 30 × 22 mm2, the roundabout micro-channel is the 90 μm width, 40 μm depth. Two micro-heater with the nickel-chrome alloy material film are formed on the side of silicon belonging to denaturation and renaturation zones needed for PCR reaction, and two adiabatic structures with groove on side of silicon by anisotropy etching. By the mede of heating local zones at single side,three wider constant temperature zones could be formed, which are 60 ℃ ,72 ℃ ,95 ℃ and suitable for PCR,and the temperature-difference could be restricted in less than 5 ℃.

  20. Cardiac surgery during pregnancy: Continuous fetal monitoring using umbilical artery Doppler flow velocity indices

    Directory of Open Access Journals (Sweden)

    Manisha Mishra

    2014-01-01

    Full Text Available The fetal death rate associated with cardiac surgery with cardiopulmonary bypass (CPB is as high as 9.5-29%. We report continuous monitoring of fetal heart rate and umbilical artery flow-velocity waveforms by transvaginal ultrasonography and their analyses in relation to events of the CPB in two cases in second trimester of pregnancy undergoing mitral valve replacement. Our findings suggest that the transition of circulation from corporeal to extracorporeal is the most important event during surgery; the associated decrease in mean arterial pressure (MAP at this stage potentially has deleterious effects on the fetus, which get aggravated with the use of vasopressors. We suggest careful management of CPB at this stage, which include partial controlled CPB at initiation and gradual transition to full CPB; this strategy maintains high MAP and avoids the use of vasopressors. Maternal and fetal monitoring can timely recognize the potential problems and provide window for the required treatment.

  1. Nonequilibrium chemical instabilities in continuous flow stirred tank reactors: The effect of stirring

    Science.gov (United States)

    Horsthemke, W.; Hannon, L.

    1984-11-01

    We present a stochastic model for stirred chemical reactors. In the limiting case of practical interest, i.e., fast stirring, we solve for the characteristic function in steady state and derive expressions for the stationary moments through a perturbation expansion. Moments are explicitly calculated for a generic model of bistable behavior. We find that stirring decreases the area of the bistable region essentially by changing the point of transition from the high reaction rate state to the low reaction rate state. This is in remarkable agreement with the experimental findings of Roux, et al. Our results indicate that stirring should not be considered simply as an ``enhanced diffusion'' process and that nucleation plays only a minor role in transitions between multiple steady states in a continuous flow stirred tank reactor (CSTR).

  2. Time Resolved Particle Image Velocimetry Techniques with Continuous Wave Laser and their Application to Transient Flows

    Science.gov (United States)

    Esposito, Chiara

    The demand to increase the temporal resolution of Stereo-Particle Image Velocimetry systems used in the measurement of highly unsteady flow fields is limited by the low repetition rate of the pulse lasers and cameras. The availability of high-frame-rate digital cameras and CW lasers opens new possibilities in the development of continuous PIV systems with increased temporal resolution. Time-Resolved Particle Image Velocimetry (TR-PIV) with continuous wave (CW) laser sheet technique and a high frame-rate camera is introduced here to be used in gas flows at low to moderate Reynolds numbers. This experimental technique can measure velocity of the flow in a planar field with good spatial and temporal resolution. Additional modifications led to the development of a Split view TR-PIV system capable of resolving three-component velocity fields. The optical setup consists of a single high-frame-rate camera which can accommodate two simultaneous stereo view images of the deforming fluid on its CMOS chip obtained by using four different planar mirrors, appropriately positioned. This approach offers several advantages over traditional systems with two different cameras. First, it provides identical system parameters for the two views which minimize their differences and thus facilitating robust stereo matching. Second, it reduces calibration time since only one camera is used and third its cost is substantially lower than the cost of a system with two cameras. The TR-PIV with the CW laser technique has been evaluated in canonical turbulent boundary layer flows and the results were compared to data from the vast literature. Particular attention has been given to the performance of the system components, such as the high speed cameras, and the CW lasers. The techniques were also investigated in terms of the duration of exposure of PIV images. The effect of the duration of exposure was proven to be particularly important, and it has a negative effect for the case with higher

  3. Polyaniline coated micro-capillaries for continuous flow analysis of aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Florea, Larisa; Diamond, Dermot [CLARITY: Centre for Sensor Web Technologies, National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin (Ireland); Benito-Lopez, Fernando, E-mail: fernando.lopez@dcu.ie [CLARITY: Centre for Sensor Web Technologies, National Centre for Sensor Research, School of Chemical Sciences, Dublin City University, Dublin (Ireland); CIC MicroGUNE, Microtechnologies Cooperative Research Center, Arrasate-Mondragon (Spain)

    2013-01-08

    Highlights: Black-Right-Pointing-Pointer Microcapillaries were coated with polyaniline nanofibres by the grafting approach. Black-Right-Pointing-Pointer Optical detection of aqueous ammonia in continuous flow mode was achieved. Black-Right-Pointing-Pointer The sensing platform can be easily regenerated after detection. Black-Right-Pointing-Pointer Very small volumes of analytes are necessary for detection. Black-Right-Pointing-Pointer The nanostructure of the coating guarantees fast response and regeneration times. - Abstract: The inner walls of fused silica micro-capillaries were successfully coated with polyaniline nanofibres using the 'grafting' approach. The optical response of polyaniline coatings was evaluated during the subsequent redoping-dedoping processes with hydrochloric acid and ammonia solutions, respectively, that were passed inside the micro-capillary in continuous flow. The optical absorbance of the polyaniline coatings was measured and analysed in the wavelength interval of [300-850 nm] to determine its optical sensitivity to different concentrations of ammonia. It was found that the optical properties of polyaniline coatings change in response to ammonia solutions in a wide concentration range from 0.2 ppm to 2000 ppm. The polyaniline coatings employed as a sensing material for the optical detection of aqueous ammonia have a fast response time and a fast regeneration time of less than 5 s at room temperature. The coating was fully characterised by scanning electron microscopy, Raman spectroscopy, absorbance measurements and kinetic studies. The response of the coatings showed very good reproducibility, demonstrating that this platform can be used for the development of micro-capillary integrated sensors based on the inherited sensing properties of polyaniline.

  4. Multi-electrode continuous flow microbial electrolysis cell for biogas production from acetate

    KAUST Repository

    Rader, Geoffrey K.

    2010-09-01

    Most microbial electrolysis cells (MECs) contain only a single set of electrodes. In order to examine the scalability of a multiple-electrode design, we constructed a 2.5 L MEC containing 8 separate electrode pairs made of graphite fiber brush anodes pre-acclimated for current generation using acetate, and 304 stainless steel mesh cathodes (64 m2/m3). Under continuous flow conditions and a one day hydraulic retention time, the maximum current was 181 mA (1.18 A/m2, cathode surface area; 74 A/m 3) within three days of operation. The maximum hydrogen production (day 3) was 0.53 L/L-d, reaching an energy efficiency relative to electrical energy input of ηE = 144%. Current production remained relatively steady (days 3-18), but the gas composition dramatically shifted over time. By day 16, there was little H2 gas recovered and methane production increased from 0.049 L/L-d (day 3) to 0.118 L/L-d. When considering the energy value of both hydrogen and methane, efficiency relative to electrical input remained above 100% until near the end of the experiment (day 17) when only methane gas was being produced. Our results show that MECs can be scaled up primarily based on cathode surface area, but that hydrogen can be completely consumed in a continuous flow system unless methanogens can be completely eliminated from the system. © 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.

  5. POWER FLOW ANALYSIS AND APPLICATION SIMULATION OF ELECTROMAGNETIC CONTINUOUSLY VARIABLE TRANSMISSION

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    With the structure of two air gaps and two rotors, the electromagnetic continuously variable transmission(EMCVT) is a novel power-split continuously variable transmission(CVT). There are two kinds of power flowing through the EMCVT, one is mechanical power and the other is electric power. In the mean time, there are three power ports in the EMCVT, one is the outer rotor named mechanical power port and the other two are the inner rotor and the stator named electric power ports. The mechanical power port is connected to the driving wheels through the final gear and the electric ports are connected to the batteries through the transducers. The two kinds of power are coupled on the outer rotor of the EMCVT. The EMCVT can be equipped on the conventional vehicle being regarded as the CVT and it also can be equipped on the hybrid electric vehicle(HEV) as the multi-energy sources assembly. The power flows of these two kinds of applications are analysed. The back electromotive force(EMF) equations are illatively studied and so the dynamic mathematic model is theorized. In order to certify the feasibility of the above theories, three simulations are carried out in allusion to the above two kinds of mentioned applications of the EMCVT and a five speed automatic transmission(AT) vehicle. The simulation results illustrate that the efficiency of the EMCVT vehicles is higher than that of the AT vehicle owed to the optimized operation area of the engine. Hence the fuel consumption of the EMCVT vehicles is knock-down.

  6. Stop-flow Lithography to Continuously Fabricate Microlens Structures Utilizing an Adjustable Three-Dimensional Mask

    Directory of Open Access Journals (Sweden)

    Shih-Hao Huang

    2014-09-01

    Full Text Available Stop-flow lithography (SFL is a microfluidic-based particle synthesis method, in which photolithography with a two dimensional (2D photomask is performed in situ within a microfluidic environment to fabricate multifunctional microstructures. Here, we modified the SFL technique by utilizing an adjustable electrostatic-force-modulated 3D (EFM-3D mask to continuously fabricate microlens structures for high-throughput production. The adjustable EFM-3D mask contains a layer filled with a UV-absorbing liquid and transparent elastomer structures in the shape of microlenses between two conductive glass substrates. An acrylate oligomer stream is photopolymerized via the microscope projection photolithography, where the EFM-3D mask was set at the field-stop plane of the microscope, thus forming the microlens structures. The produced microlens structures flow downstream without adhesion to the polydimethysiloxane (PDMS microchannel surfaces due to the existence of an oxygen-aided inhibition layer. Microlens structures with variations in curvature and aperture can be produced by changing objective magnifications, controlling the morphology of the EFM-3D mask through electrostatic force, and varying the concentration of UV-light absorption dyes. We have successfully demonstrated to produce microlens structures with an aperture ranging from 50 μm to 2 mm and the smallest focus spot size of 0.59 μm. Our proposed method allows one to fabricate microlens structures in a fast, simple and high-throughput mode for application in micro-optical systems.

  7. Numerical study of steady turbulent flow through bifurcated nozzles in continuous casting

    Science.gov (United States)

    Najjar, Fady M.; Thomas, Brian G.; Hershey, Donald E.

    1995-08-01

    Bifurcated nozzles are used in continuous casting of molten steel, where they influence the quality of the cast steel slabs. The present study performs two-dimensional (2-D) and three-dimensional (3-D) simulations of steady turbulent (K- ɛ) flow in bifurcated nozzles, using a finite-element (FIDAP) model, which has been verified previously with water model experiments. The effects of nozzle design and casting process operating variables on the jet characteristics exiting the nozzle are investigated. The nozzle design parameters studied include the shape, angle, height, width, and thickness of the ports and the bottom geometry. The process operating practices include inlet velocity profile and angle as well as port curvature caused by erosion or inclusion buildup. Results show that the jet angle is controlled mainly by the port angle but is steeper with larger port area and thinner walls. The degree of swirl is increased by larger or rounder ports. The effective port area, where there is no recirculation, is increased by smaller or curved ports. Flow asymmetry is more severe with skewed or angled inlet conditions or unequal port sizes. Turbulence levels in the jet are higher with higher casting speed and smaller ports.

  8. Low-cost, real-time, continuous flow PCR system for pathogen detection.

    Science.gov (United States)

    Fernández-Carballo, B Leticia; McGuiness, Ian; McBeth, Christine; Kalashnikov, Maxim; Borrós, Salvador; Sharon, Andre; Sauer-Budge, Alexis F

    2016-04-01

    In this paper, we present a portable and low cost point-of-care (POC) PCR system for quantitative detection of pathogens. Our system is based on continuous flow PCR which maintains fixed temperatures zones and pushes the PCR solution between two heated areas allowing for faster heat transfer and as a result, a faster PCR. The PCR system is built around a 46.0 mm × 30.9 mm × 0.4 mm disposable thermoplastic chip. In order to make the single-use chip economically viable, it was manufactured by hot embossing and was designed to be compatible with roll-to-roll embossing for large scale production. The prototype instrumentation surrounding the chip includes two heaters, thermal sensors, and an optical system. The optical system allows for pathogen detection via real time fluorescence measurements. FAM probes were used as fluorescent reporters of the amplicons generated during the PCR. To demonstrate the function of the chip, two infectious bacteria targets were selected: Chlamydia trachomatis and Escherichia coli O157:H7. For both bacteria, the limit of detection of the system was determined, PCR efficiencies were calculated, and different flow velocities were tested. We have demonstrated successful detection for these two bacterial pathogens highlighting the versatility and broad utility of our portable, low-cost, and rapid PCR diagnostic device.

  9. Salt removal using multiple microbial desalination cells under continuous flow conditions

    KAUST Repository

    Qu, Youpeng

    2013-05-01

    Four microbial desalination cells (MDCs) were hydraulically connected and operated under continuous flow conditions. The anode solution from the first MDC flowed into the cathode, and then on to the anode of the next reactor, which avoided pH imbalances that inhibit bacterial metabolism. The salt solution also moved through each desalination chamber in series. Increasing the hydraulic retention times (HRTs) of the salt solution from 1 to 2. days increased total NaCl removal from 76 ± 1% to 97 ± 1%, but coulombic efficiencies decreased from 49 ± 4% to 35 ± 1%. Total COD removals were similar at both HRTs (60 ± 2%, 2. days; 59 ± 2%, 1. day). Community analysis of the anode biofilms showed that bacteria most similar to the xylose fermenting bacterium Klebsiella ornithinolytica predominated in the anode communities, and sequences most similar to Geobacter metallireducens were identified in all MDCs except the first one. These results demonstrated successful operation of a series of hydraulically connected MDCs and good desalination rates. © 2013 Elsevier B.V..

  10. Fluid Flow and Mixing in Non-Isothermal Water Model of Continuous Casting Tundish

    Institute of Scientific and Technical Information of China (English)

    Mehdi ALIZADEH; Hossein EDRIS; Ali SHAFYEI

    2008-01-01

    Fluid flow and mixing of molten steel in a twin-slab-strand continuous casting tundish were investigated using a mixing model under non-isothermal conditions. This model led to a set of ordinary differential equations that were solved with a Runge-Kutta algorithm. Steady state water modeling was carried out under non-isothermal conditions. Experimental data obtained from the water model were used to calibrate the mixing model. Owing to the presence of a mixed convection in the non-isothermal conditions, a channelizing flow would be created in the fluid inside the tundish. A mixing model was designed that was capable of predicting RTD (residence time distribution) curves for different cases in non-isothermal conditions. The relationship between RTD parameters and the Tu (tundish Richardson number) was obtained for various cases under non-isothermal conditions. The results show that the RTD parameters were completely different under isothermal and non-isothermal conditions. The comparison of the RTD curves between the isothermal and non-isothermal conditions presents that the extent of mixing in the tundish in nonisothermal conditions is lower than the mixing extent in isothermal conditions.

  11. Simultaneous phosphorus and nitrogen removal in a continuous-flow two-sludge system

    Institute of Scientific and Technical Information of China (English)

    LI Xiang-kun; HUANG Rong-xin; BAO Lin-lin; SHAO Chun-hong; ZHANG Jie

    2006-01-01

    The ability of simultaneous biological phosphorus and nitrogen removal was investigated in a lab-scale continuous-flow two-sludge system. Alternating anaerobic and anoxic conditions were combined with contact oxidation stage for treating raw municipal wastewater. Long-term experiments showed that the contradiction of competing for the organic substrate between denitrifying bacteria and PAOs (phosphorus accumulating organisms) in traditional phosphorus and nitrogen removal system has been resolved. The system can adapt to low influent COD/TN ratio (C/N). Furthermore the SRT (sludge retention time) of nitrifying sludge and denitrifying phosphorus removal sludge can be controlled at optimal conditions respectively. The removal efficiency of COD, TP,TN, and NH4-N was 81.78%, 92.51%, 75.75%, and 84.47% respectively. It was also found that the appropriate influent C/N should be controlled at the range of 3.8-6, while the optimal C/N to the system ranged between 4-5, and the BFR (bypass sludge flow rate)should be controlled at 0.35 around.

  12. Continuous-flow multi-analyte biosensor cartridge with controllable linear response range.

    Science.gov (United States)

    Frey, Olivier; Talaei, Sara; van der Wal, Peter D; Koudelka-Hep, Milena; de Rooij, Nico F

    2010-09-01

    This article presents the design and fabrication of a microfluidic biosensor cartridge for the continuous and simultaneous measurement of biologically relevant analytes in a sample solution. The biosensor principle is based on the amperometric detection of hydrogen peroxide using enzyme-modified electrodes. The low-integrated and disposable cartridge is fabricated in PDMS and SU-8 by rapid prototyping. The device is designed in such a way that it addresses two major challenges of biosensors using microfluidics approaches. Firstly, the enzymatic membrane is deposited on top of the platinum electrodes via a microfluidic deposition channel from outside the cartridge. This decouples the membrane deposition from the cartridge fabrication and enables the user to decide when and with what mixture he wants to modify the electrode. Secondly, by using laminar sheath-flow of the sample and a buffer solution, a dynamic diffusion layer is created. The analyte has to diffuse through the buffer solution layer before it can reach the immobilized enzyme membrane on the electrode. Controlling of the thickness of the diffusion layer by variation of the flow-rate of the two layers enables the user to adjust the sensitivity and the linear region of the sensor. The point where the buffer and sample stream join proved critical in creating the laminar sheath-flow. Results of computational simulations considering fluid dynamics and diffusion are presented. The consistency of the device was investigated through detection of glucose and lactate and are in accordance with the CFD simulations. A sensitivity of 157+/-28 nA/mM for the glucose sensor and 79+/-12 nA/mM for the lactate sensor was obtained. The linear response range of these biosensors could be increased from initially 2 mM up to 15 mM with a limit of detection of 0.2 mM.

  13. UVC-induced lysis and detritus production of Oscillatoria limnetica in a two-stage continuous-flow system

    NARCIS (Netherlands)

    Van Hannen, E.J.; Gons, H.J.

    1997-01-01

    In order to study in model systems the role of heterotrophic micro-organisms in the aquatic microbial food web, a natural food source consisting of senescent primary producer cells is indispensable. A two-stage continuous-flow system with the ability to produce detritus continuously is presented. In

  14. Design and testing of a unique randomized gravity, continuous flow bioreactor

    Science.gov (United States)

    Lassiter, Carroll B.

    1993-01-01

    high concentrations of oxygen into the culture medium. The system described allows for continuous, on line sampling for production of product without disturbing fluid and particle dynamics in the reaction chamber. It provides for the introduction of substrate, or control substances after cell adaptation to simulated microgravity has been accomplished. The reactor system provides for the nondisruptive, continuous flow replacement of nutrient and removal of product. On line monitoring and control of growth conditions such as pH and nutrient status are provided. A rotating distribution valve allows cessation of growth chamber rotation, thereby preserving the simulated microgravity conditions over longer periods of time.

  15. Forming-free, bi-directional polarity conductive-bridge memory devices with Ge2Sb2Te5 solid-state electrolyte and Ag active electrode

    Science.gov (United States)

    Huang, Yin-Hsien; Chen, Hsuan-An; Wu, Hsin-Han; Hsieh, Tsung-Eong

    2015-01-01

    Preparation and characteristics of conductive-bridge random access memory devices containing Ge2Sb2Te5 (GST) chalcogenide as the solid-state electrolyte, Ag as the active electrode, and W-Ti as the counter electrode are presented. As revealed by the electrical measurement, only the samples containing crystalline GST exhibited the resistive switching behaviors. With an insertion of ZnS-SiO2 dielectric layer at the Ag/GST interface and a postannealing at 100 °C for 1 min, the sample exhibited the best electrical performance with satisfactory cycleability and retention properties. Moreover, the forming-free and bi-directional polarity features were observed in such a sample type. Microstructure and composition analyses found the finely dispersed nano-scale Ag clusters in GST and, when electrical bias is applied, the migrating Ag ions may build up the connections in between neighboring Ag clusters. Moreover, grain boundaries in polycrystalline GST might be the main paths for Ag migration. The thread-like conduction channels in GST hence form, leading to the low resistance state of sample. On the contrary, the depletion of Ag in GST broke the connections in between Ag clusters when the electrical bias is reversed. This led to the rupture of conduction channels and, hence, the high resistance state of sample. The low operational voltage, forming-free, and bi-directional polarity features observed in (AZGW)T sample might also originated from the fine dispersion of Ag clusters in GST electrolyte.

  16. Novel Bi-directional Converter for Photovoltaic LED Illuminatce System%光伏LED照明系统中双向变换器研究

    Institute of Scientific and Technical Information of China (English)

    汪义旺; 张波; 曹丰文; 吴铄

    2011-01-01

    研究设计了一种应用于光伏LED照明系统的改进型Zeta/Speic双向变换电路,该电路兼顾MPPT控制、蓄电池充放电控制、LED恒流控制及隔离保护控制等多种功能,与传统光伏LED照明系统中的常规变换器相比,具有结构简单灵活、成本低、效率高等优点.详细分析了电路组成及工作模式,并通过实验进行了测试,测试结果验证了该变换器的有效性及优越性.%A novel bi-directional Zeta/Speic converter for LED photovoltaic illuminatce system is analyzed and designed, which can realize MPPT control,battery charge and discharge control,LED current control and isolation control function,compared with the traditional DC/DC converters for LED photovoltaic illuminatce system,has simple structure flexible, low cost and high efficiency ad vantages. The consists of the circuit and working model are analyzed. Finally the test experimental waveforms of prototype are given to demonstrate the goodness of this novel bi-directional Zeta/Speic converter.

  17. Insulin-like growth factor-I and slow, bi-directional perfusion enhance the formation of tissue-engineered cardiac grafts.

    Science.gov (United States)

    Cheng, Mingyu; Moretti, Matteo; Engelmayr, George C; Freed, Lisa E

    2009-03-01

    Biochemical and mechanical signals enabling cardiac regeneration can be elucidated using in vitro tissue-engineering models. We hypothesized that insulin-like growth factor-I (IGF) and slow, bi-directional perfusion could act independently and interactively to enhance the survival, differentiation, and contractile performance of tissue-engineered cardiac grafts. Heart cells were cultured on three-dimensional porous scaffolds in medium with or without supplemental IGF and in the presence or absence of slow, bi-directional perfusion that enhanced transport and provided shear stress. Structural, molecular, and electrophysiologic properties of the resulting grafts were quantified on culture day 8. IGF had independent, beneficial effects on apoptosis (p < 0.01), cellular viability (p < 0.01), contractile amplitude (p < 0.01), and excitation threshold (p < 0.01). Perfusion independently affected the four aforementioned parameters and also increased amounts of cardiac troponin-I (p < 0.01), connexin-43 (p < 0.05), and total protein (p < 0.01) in the grafts. Interactive effects of IGF and perfusion on apoptosis were also present (p < 0.01). Myofibrillogenesis and spontaneous contractility were present only in grafts cultured with perfusion, although contractility was inducible by electrical field stimulation of grafts from all groups. Our findings demonstrate that multi-factorial stimulation of tissue-engineered cardiac grafts using IGF and perfusion resulted in independent and interactive effects on heart cell survival, differentiation, and contractility. PMID:18759675

  18. Relaxed damage threshold intensity conditions and nonlinear increase in the conversion efficiency of an optical parametric oscillator using a bi-directional pump geometry.

    Science.gov (United States)

    Norris, G; McConnell, G

    2010-03-01

    A novel bi-directional pump geometry that nonlinearly increases the nonlinear optical conversion efficiency of a synchronously pumped optical parametric oscillator (OPO) is reported. This bi-directional pumping method synchronizes the circulating signal pulse with two counter-propagating pump pulses within a linear OPO resonator. Through this pump scheme, an increase in nonlinear optical conversion efficiency of 22% was achieved at the signal wavelength, corresponding to a 95% overall increase in average power. Given an almost unchanged measured pulse duration of 260 fs under optimal performance conditions, this related to a signal wavelength peak power output of 18.8 kW, compared with 10 kW using the traditional single-pass geometry. In this study, a total effective peak intensity pump-field of 7.11 GW/cm(2) (corresponding to 3.55 GW/cm(2) from each pump beam) was applied to a 3 mm long periodically poled lithium niobate crystal, which had a damage threshold intensity of 4 GW/cm(2), without impairing crystal integrity. We therefore prove the application of this novel pump geometry provides opportunities for power-scaling of synchronously pumped OPO systems together with enhanced nonlinear conversion efficiency through relaxed damage threshold intensity conditions.

  19. An Introduction of Bi-direction Module Reading Method Based on Instructional Scaffolding%基于支架教学法的双向模块阅读

    Institute of Scientific and Technical Information of China (English)

    顾锡涛

    2012-01-01

      The bi-direction module reading method based on instructional scaffolding is a fast reading method with bi-direction understanding which is from text to question and from question to text. In the course of teaching, teachers can build different kinds of scaffolding to develop students’ reading skills and help them form good reading habits so that they can do autonomous reading without scaffolding.%  基于支架教学法的双向模块阅读是从文章到问题和从问题到文章的双向理解的快速阅读方法,在教学过程中教师可以通过建立各种支架不断培养学生阅读能力,形成好的阅读习惯,最终达到摆脱支架形成自主能力。

  20. 超声波流量计双向流计量研究%Study on the Measurement of Bi-directional Flow with Ultrasonic Flow Meter

    Institute of Scientific and Technical Information of China (English)

    郑宝昌; 李培清; 齐畅

    2003-01-01

    对超声波流量计双向流计量进行了实地测量.测量结果表明不同生产商生产的超声波流量计测量精度不同,实际应用时,应根据反向计量精度不同的特点,选择合适的流量计.

  1. Study of the Behavior of the Mercury on Diverse Microelectrodes with Cell of Continuous Flow

    International Nuclear Information System (INIS)

    A comparative study of six types of microelectrodes in two different support electrolytes was developed using a new analytic technique for analysis of mercury in liquid samples in the ambit of parts by million. For it, a new system of cell of continuous flow and platinum microelectrodes and of platinum with gold film was implemented using volt-amperemetry of anodized spoil with square wave. In a preliminary study, some parameters that characterize the analysis with this new cell were optimized, for example the sample's speed flow and the time of electrodeposition. The calibration curves were made for the different types of microelectrode that were used in an ambit of concentrations of 1-10 ppm. According to the obtained results, the microelectrode that better works is the platinum disk for possessing bigger superficial area exposed to the dissolution, which increases the analite's currents of pick. And as a support electrolyte, potassium tiocianato is recommended because of its effectiveness to solve the analytic sign of the mercury. Studies of answer of the current of mercury regarding the quantity of the placed sample and studies of interferences of the analysis with this type of microelectrode were also carried out. With regard to the study of the quantity of sample, it was obtained that the electrochemical answer of the cell is directly proportional to the concentration of the analite placed in it. In the study of interference, it was found that the copper, lead, and zinc ions affect the analysis of mercury in concentrations of 0.1 ppm and on in the case of the microelectrode of platinum disk. And in case that the same microelectrode is used recovered with gold, it only affects the copper in concentrations over 5 ppm, for what is necessary to take into account a previous treatment of the sample in the event of containing some of the interfering ions

  2. Gas exchange and intrapulmonary distribution of ventilation during continuous-flow ventilation

    International Nuclear Information System (INIS)

    In 12 anesthetized paralyzed dogs, pulmonary gas exchange and intrapulmonary inspired gas distribution were compared between continuous-flow ventilation (CFV) and conventional mechanical ventilation (CMV). Nine dogs were studied while they were lying supine, and three dogs were studied while they were lying prone. A single-lumen catheter for tracheal insufflation and a double-lumen catheter for bilateral endobronchial insufflation [inspired O2 fraction = 0.4; inspired minute ventilation = 1.7 +/- 0.3 (SD) 1.kg-1.min-1] were evaluated. Intrapulmonary gas distribution was assessed from regional 133Xe clearances. In dogs lying supine, CO2 elimination was more efficient with endobronchial insufflation than with tracheal insufflation, but the alveolar-arterial O2 partial pressure difference was larger during CFV than during CMV, regardless of the type of insufflation. By contrast, endobronchial insufflation maintained both arterial PCO2 and alveolar-arterial O2 partial pressure difference at significantly lower levels in dogs lying prone than in dogs lying supine. In dogs lying supine, the dependent lung was preferentially ventilated during CMV but not during CFV. In dogs lying prone, gas distribution was uniform with both modes of ventilation. The alveolar-arterial O2 partial pressure difference during CFV in dogs lying supine was negatively correlated with the reduced ventilation of the dependent lung, which suggests that increased ventilation-perfusion mismatching was responsible for the increase in alveolar-arterial O2 partial pressure difference. The more efficient oxygenation during CFV in dogs lying prone suggests a more efficient matching of ventilation to perfusion, presumably because the distribution of blood flow is also nearly uniform

  3. Incidence of electrocardiographic changes during cytapheresis using an intermittent flow centrifuge, haemonetics V50 and a continuous flow centrifuge, AS104.

    Science.gov (United States)

    Komatsu, F; Kajiwara, M

    1997-03-01

    Electrocardiographic (ECG) monitoring was performed during cytapheresis and the incidence of ECG changes was compared between methods of intermittent flow centrifugation using the Haemonetics V50 with apheresis donors and continuous flow centrifugation with the AS104 for peripheral blood stem cell (PBSC) collection from patients. ST depression, inverted T wave and other ECG changes were found in 49 (14.3%) of the 342 cytaphereses carried out by the intermittent flow centrifugation method and in 8 (4.7%) of the 169 PBSC collections by the continuous flow centrifugation method. This difference was significant (P < 0.05). The hemodynamic changes in the procedure with the AS104 seem to be small. This is considered to be important for prevention of serious ST and T wave changes.

  4. A Microfluidic Device for Continuous-Flow Magnetically Controlled Capture and Isolation of Microparticles.

    Science.gov (United States)

    Zhou, Yao; Wang, Yi; Lin, Qiao

    2010-08-01

    This paper presents a novel microfluidic device that exploits magnetic manipulation for integrated capture and isolation of microparticles in continuous flow. The device, which was fabricated from poly(dimethylsiloxane) (PDMS) by soft-lithography techniques, consists of an incubator and a separator integrated on a single chip. The incubator is based on a novel scheme termed target acquisition by repetitive traversal (TART), in which surface-functionalized magnetic beads repetitively traverse a sample to seek out and capture target particles. This is accomplished by a judicious combination of a serpentine microchannel geometry and a time-invariant magnetic field. Subsequently, in the separator, the captured target particles are isolated from nontarget particles via magnetically driven fractionation in the same magnetic field. Due to the TART incubation scheme that uses a corner-free serpentine channel, the device has no dead volume and allows minimization of undesired particle or magnetic-bead retention. Single-chip integration of the TART incubator with the magnetic-fractionation separator further allows automated continuous isolation and retrieval of specific microparticles in an integrated manner that is free of manual off-chip sample incubation, as often required by alternative approaches. Experiments are conducted to characterize the individual incubation and separation components, as well as the integrated device. The device is found to allow 90% of target particles in a sample to be captured and isolated and 99% of nontarget particles to be eliminated. With this high separation efficiency, along with excellent reliability and flexibility, the device is well suited to sorting, purification, enrichment, and detection of micro/nanoparticles and cells in lab-on-a-chip systems. PMID:24511214

  5. Comparison of Reductive Dechlorination of Chlorinated Ethylene in Batch and Continuous-Flow Reactor

    Science.gov (United States)

    Park, S.; Jonghwan, L.; Hong, U.; Kim, N.; Ahn, H.; Lee, S.; Kim, Y.

    2010-12-01

    A 1.28 L-Batch reactor and continuous-flow stirred tank reactor (CFSTR) fed with formate and trichloriethene (TCE) were operated for 120 days and 72 days, respectively, to study the effect of formate as electron donor on reductive dechlorination of TCE to cis-1,2-dichloroethylene (c-DCE), vinyl chloride (VC), and ethylene (ETH). In batch reactor, injected 60 μmol TCE was completely degraded in presence of 20% hydrogen gas (H2) in less than 8 days by Evanite culture (300 mg-soluble protein) with ability to completely degrade tetrachloroethene (PCE) and TCE to ETH under anaerobic conditions. To determine the effect of formate as electron donor instead of H2, about 3 or 11 mmol of formate injected into batch-reactor every 15 days was enough to support H2 for dechlorination of c-DCE to VC and ETH. Soluble protein concentration of Evanite culture during the batch test increased from 300 mg to 688 mg for 120 days. In CFSTR test, TCE was fed continuously at 9.9 ppm (75.38 μmol/L) and the influent formate feed concentration increased stepwise from 1.3 mmol/L to 14.3 mmol/L. Injected TCE was accumulated at HRT 18 days for 13 days, but TCE was completed degraded at HRT 36 days without accumulation during left of experiment period, getting H2 from fermentative hydrogen production of injected formate. Although c-DCE was also accumulated for 23 days after CFSTR operation, it reached steady-state without accumulation in presence of excessive formate. However, since c-DCE in CFSTR was not completely dechlorinated, we will determine the transcriptional level of enzyme involved in reductive dechlorination of TCE, c-DCE, and VC in our future work.

  6. Safe, Selective, and High-Yielding Synthesis of Acryloyl Chloride in a Continuous-Flow System.

    Science.gov (United States)

    Movsisyan, Marine; Heugebaert, Thomas S A; Dams, Rudy; Stevens, Christian V

    2016-08-01

    Acid chlorides are an important class of compounds and their high reactivity and instability has prompted us to develop a straightforward procedure for their synthesis with on-demand and on-site synthesis possibilities. The focus of this report is acryloyl chloride, mainly important for the acrylate and polymer industry. A continuous-flow methodology was developed for the fast and selective synthesis of the otherwise highly unstable acryloyl chloride. Three routes were investigated in a microreactor setup and all three can potentially be used for its production. The methodology was further expanded to the synthesis of other unstable acid chlorides by both the thionyl chloride and the oxalyl chloride mediated processes. The most sustainable method was the oxalyl chloride mediated procedure under solvent-free conditions, in which near-equimolar amounts of carboxylic acid and oxalyl chloride were used in the presence of catalytic amounts of DMF at room temperature. Within 1 to 3 min, nearly full conversions into the acid chlorides were achieved. PMID:27325562

  7. Stopped-flow DNA polymerase assay by continuous monitoring of dNTP incorporation by fluorescence.

    Science.gov (United States)

    Montgomery, Jesse L; Rejali, Nick; Wittwer, Carl T

    2013-10-15

    DNA polymerase activity was measured by a stopped-flow assay that monitors polymerase extension using an intercalating dye. Double-stranded DNA formation during extension of a hairpin substrate was monitored at 75°C for 2 min. Rates were determined in nucleotides per second per molecule of polymerase (nt/s) and were linear with time and polymerase concentration from 1 to 50 nM. The concentrations of 15 available polymerases were quantified and their extension rates determined in 50 mM Tris, pH 8.3, 0.5 mg/ml BSA, 2 mM MgCl₂, and 200 μM each dNTP as well as their commercially recommended buffers. Native Taq polymerases had similar extension rates of 10-45 nt/s. Three alternative polymerases showed faster speeds, including KOD (76 nt/s), Klentaq I (101 nt/s), and KAPA2G (155 nt/s). Fusion polymerases including Herculase II and Phusion were relatively slow (3-13 nt/s). The pH optimum for Klentaq extension was between 8.5 and 8.7 with no effect of Tris concentration. Activity was directly correlated to the MgCl2 concentration and inversely correlated to the KCl concentration. This continuous assay is relevant to PCR and provides accurate measurement of polymerase activity using a defined template without the need of radiolabeled substrates. PMID:23872003

  8. Preventing rubidium runaway in a compact continuous-flow SEOP hyperpolariser for xenon NMR

    Energy Technology Data Exchange (ETDEWEB)

    Witte, Christopher; Kunth, Martin; Rossella, Federica; Schroeder, Leif [Leibniz-Institut fuer Molekulare Pharmakologie (FMP), Berlin (Germany)

    2012-07-01

    Hyperpolarised noble gases have many applications in medical physics such as magnetic resonance (MR) lung imaging and MR biosensor design. Noble gases can be hyperpolarised using processes such as spin exchange optical pumping (SEOP), increasing their detectable magnetisation by 3-4 orders of magnitude above thermal polarisation. In SEOP the easily generated angular momentum of laser light is used to polarise rubidium and through collisions this is then transferred to the noble gas. Recently available high power diode laser have the potential to efficiently pump rubidium even at high vapour pressures. Unfortunately in most compact SEOP polarisers the increased laser power can cause excessive heating of the pumping cell. This leads to a deleterious process known as rubidium runaway. We present a modified continuous-flow hyperpolariser for xenon MR studies specifically designed to overcome this problem. Utilising thermal management we can dissipate this excess heat and prevent rubidium runaway while maintaining a compact design. When increasing the laser power from 100 to 150 W with optimised temperatures we observed an increase in xenon spin polarisation by a factor of 4.

  9. Ex Vivo Assessment of a Parabolic-Tip Inflow Cannula for Pediatric Continuous-Flow VADs.

    Science.gov (United States)

    Griffin, Michael T; Grzywinski, Matthew F; Voorhees, Hannah J; Kameneva, Marina V; Olia, Salim E

    2016-01-01

    To address the challenge of unloading the left ventricle during pediatric mechanical circulatory support using next-generation rotary blood pumps, a novel inflow cannula was developed. This unique inflow cannula for pediatric, continuous-flow, left ventricular assist devices (VADs) with a parabolic-shaped inlet entrance was evaluated alongside a bevel-tip and fenestrated-tip cannula via an ex vivo, isolated-heart experimental setup. Performance was characterized using two clinical scenarios of over-pumping and hypovolemia, created by varying pump speed and filling preload pressure, respectively, at ideal and off-axis cannula placement to assess ventricular unloading and positional sensitivity. Quantitative and qualitative assessments were performed on the resultant hemodynamics and intra-ventricular boroscopic images to classify conditions of nonsuction, partial, gradual or severe entrainment, and ventricular collapse. The parabolic-tip cannula was found to be significantly less sensitive to placement position (p pumping and hypovolemic studies, respectively. We conclude that future pediatric VAD designs may benefit from incorporating the parabolic-tip inflow cannula design to maximize unloading of the left ventricle in ideal and nonoptimal conditions. PMID:27442862

  10. A three-step method for analysing bacterial biofilm formation under continuous medium flow.

    Science.gov (United States)

    Schmutzler, Karolin; Schmid, Andreas; Buehler, Katja

    2015-07-01

    For the investigation and comparison of microbial biofilms, a variety of analytical methods have been established, all focusing on different growth stages and application areas of biofilms. In this study, a novel quantitative assay for analysing biofilm maturation under the influence of continuous flow conditions was developed using the interesting biocatalyst Pseudomonas taiwanensis VLB120. In contrast to other tubular-based assay systems, this novel assay format delivers three readouts using a single setup in a total assay time of 40 h. It combines morphotype analysis of biofilm colonies with the direct quantification of biofilm biomass and pellicle formation on an air/liquid interphase. Applying the Tube-Assay, the impact of the second messenger cyclic diguanylate on biofilm formation of P. taiwanensis VLB120 was investigated. To this end, 41 deletions of genes encoding for protein homologues to diguanylate cyclase and phosphodiesterase were generated in the genome of P. taiwanensis VLB120. Subsequently, the biofilm formation of the resulting mutants was analysed using the Tube-Assay. In more than 60 % of the mutants, a significantly altered biofilm formation as compared to the parent strain was detected. Furthermore, the potential of the proposed Tube-Assay was validated by investigating the biofilms of several other bacterial species.

  11. Surgical Considerations and Challenges for Bilateral Continuous-Flow Durable Device Implantation.

    Science.gov (United States)

    Maltais, Simon; Womack, Sara; Davis, Mary E; Danter, Matthew R; Kushwaha, Sudhir S; Stulak, John M; Haglund, Nicholas

    2016-01-01

    The concept of biventricular support with durable centrifugal pumps is evolving, and the surgical strategy and best practice guidelines for implantation of right-sided devices are still unknown. We present optimal strategy for bilateral HeartWare continuous-flow ventricular assist device (HVAD) implantation in a series of four patients. Patients were implanted with the HVAD pumps simultaneously or sequentially. This report offers a perspective on surgical considerations such as right ventricular positioning, implications related to potential risks of obstruction from the tricuspid apparatus, the role if any of downsizing the outflow anastomosis, and considerations for speed adjustments. In this series, one patient died on support and three patients experienced pump thrombosis requiring device revision. All other patients survived until orthotopic heart transplantation, although one of these patients died from perioperative complications, 2 days posttransplantation. Surgical management of patients with medically refractory biventricular heart failure remains challenging and associated with a high incidence of pump thrombosis. Best practice guidelines from experts' consensus are still needed to address this challenging population. PMID:26479465

  12. Sickle cell anemia: reference values of cerebral blood flow determined by continuous arterial spin labeling MRI.

    Science.gov (United States)

    Arkuszewski, M; Krejza, J; Chen, R; Melhem, E R

    2013-04-01

    Sickle cell anemia (SCA) is a chronic illness associated with progressive deterioration in patients' quality of life. The major complications of SCA are cerebrovascular accidents (CVA) such as asymptomatic cerebral infarct or overt stroke. The risk of CVA may be related to chronic disturbances in cerebral blood flow (CBF), but the thresholds of "normal" steady-state CBF are not well established. The reference tolerance limits of CBF can be useful to estimate the risk of CVA in asymptomatic children with SCA, who are negative for hyperemia or evidence of arterial narrowing. Continuous arterial spin labeling (CASL) MR perfusion allows for non-invasive quantification of global and regional CBF. To establish such reference tolerance limits we performed CASL MR examinations on a 3-Tesla MR scanner in a carefully selected cohort of 42 children with SCA (mean age, 8.1±3.3 years; range limits, 2.3-14.4 years; 24 females), who were not on chronic transfusion therapy, had no history of overt stroke or transient ischemic attack, were free of signs and symptoms of focal vascular territory ischemic brain injury, did not have intracranial arterial narrowing on MR angiography and were at low risk for stroke as determined by transcranial Doppler ultrasonography.

  13. Temperature measurements with two different IR sensors in a continuous-flow microwave heated system.

    Science.gov (United States)

    Rydfjord, Jonas; Svensson, Fredrik; Fagrell, Magnus; Sävmarker, Jonas; Thulin, Måns; Larhed, Mats

    2013-01-01

    In a continuous-flow system equipped with a nonresonant microwave applicator we have investigated how to best assess the actual temperature of microwave heated organic solvents with different characteristics. This is non-trivial as the electromagnetic field will influence most traditional methods of temperature measurement. Thus, we used a microwave transparent fiber optic probe, capable of measuring the temperature inside the reactor, and investigated two different IR sensors as non-contact alternatives to the internal probe. IR sensor 1 measures the temperature on the outside of the reactor whilst IR sensor 2 is designed to measure the temperature of the fluid through the borosilicate glass that constitutes the reactor wall. We have also, in addition to the characterization of the before mentioned IR sensors, developed statistical models to correlate the IR sensor reading to a correct value of the inner temperature (as determined by the internal fiber optic probe), thereby providing a non-contact, indirect, temperature assessment of the heated solvent. The accuracy achieved with these models lie well within the range desired for most synthetic chemistry applications. PMID:24204419

  14. Temperature measurements with two different IR sensors in a continuous-flow microwave heated system

    Directory of Open Access Journals (Sweden)

    Jonas Rydfjord

    2013-10-01

    Full Text Available In a continuous-flow system equipped with a nonresonant microwave applicator we have investigated how to best assess the actual temperature of microwave heated organic solvents with different characteristics. This is non-trivial as the electromagnetic field will influence most traditional methods of temperature measurement. Thus, we used a microwave transparent fiber optic probe, capable of measuring the temperature inside the reactor, and investigated two different IR sensors as non-contact alternatives to the internal probe. IR sensor 1 measures the temperature on the outside of the reactor whilst IR sensor 2 is designed to measure the temperature of the fluid through the borosilicate glass that constitutes the reactor wall. We have also, in addition to the characterization of the before mentioned IR sensors, developed statistical models to correlate the IR sensor reading to a correct value of the inner temperature (as determined by the internal fiber optic probe, thereby providing a non-contact, indirect, temperature assessment of the heated solvent. The accuracy achieved with these models lie well within the range desired for most synthetic chemistry applications.

  15. Examination of protein degradation in continuous flow, microbial electrolysis cells treating fermentation wastewater

    KAUST Repository

    Nam, Joo-Youn

    2014-11-01

    © 2014 Elsevier Ltd. Cellulose fermentation wastewaters (FWWs) contain short chain volatile fatty acids and alcohols, but they also have high concentrations of proteins. Hydrogen gas production from FWW was examined using continuous flow microbial electrolysis cells (MECs), with a focus on fate of the protein. H2 production rates were 0.49±0.05m3/m3-d for the FWW, compared to 0.63±0.02m3/m3-d using a synthetic wastewater containing only acetate (applied potential of 0.9V). Total organic matter removal was 76±6% for the FWW, compared to 87±5% for acetate. The MEC effluent became relatively enriched in protein (69%) compared to that in the original FWW (19%). Protein was completely removed using higher applied voltages (1.0 or 1.2V), but current generation was erratic due to more positive anode potentials (-113±38mV, Eap=1.2V; -338±38mV, 1.0V; -0.426±4mV, 0.9V). Bacteria on the anodes with FWW were primarily Deltaproteobacteria, while Archaea were predominantly Methanobacterium.

  16. Temperature measurements with two different IR sensors in a continuous-flow microwave heated system.

    Science.gov (United States)

    Rydfjord, Jonas; Svensson, Fredrik; Fagrell, Magnus; Sävmarker, Jonas; Thulin, Måns; Larhed, Mats

    2013-01-01

    In a continuous-flow system equipped with a nonresonant microwave applicator we have investigated how to best assess the actual temperature of microwave heated organic solvents with different characteristics. This is non-trivial as the electromagnetic field will influence most traditional methods of temperature measurement. Thus, we used a microwave transparent fiber optic probe, capable of measuring the temperature inside the reactor, and investigated two different IR sensors as non-contact alternatives to the internal probe. IR sensor 1 measures the temperature on the outside of the reactor whilst IR sensor 2 is designed to measure the temperature of the fluid through the borosilicate glass that constitutes the reactor wall. We have also, in addition to the characterization of the before mentioned IR sensors, developed statistical models to correlate the IR sensor reading to a correct value of the inner temperature (as determined by the internal fiber optic probe), thereby providing a non-contact, indirect, temperature assessment of the heated solvent. The accuracy achieved with these models lie well within the range desired for most synthetic chemistry applications.

  17. Ex Vivo Assessment of a Parabolic-Tip Inflow Cannula for Pediatric Continuous-Flow VADs.

    Science.gov (United States)

    Griffin, Michael T; Grzywinski, Matthew F; Voorhees, Hannah J; Kameneva, Marina V; Olia, Salim E

    2016-01-01

    To address the challenge of unloading the left ventricle during pediatric mechanical circulatory support using next-generation rotary blood pumps, a novel inflow cannula was developed. This unique inflow cannula for pediatric, continuous-flow, left ventricular assist devices (VADs) with a parabolic-shaped inlet entrance was evaluated alongside a bevel-tip and fenestrated-tip cannula via an ex vivo, isolated-heart experimental setup. Performance was characterized using two clinical scenarios of over-pumping and hypovolemia, created by varying pump speed and filling preload pressure, respectively, at ideal and off-axis cannula placement to assess ventricular unloading and positional sensitivity. Quantitative and qualitative assessments were performed on the resultant hemodynamics and intra-ventricular boroscopic images to classify conditions of nonsuction, partial, gradual or severe entrainment, and ventricular collapse. The parabolic-tip cannula was found to be significantly less sensitive to placement position (p parabolic-tip cannula showed complete resistance to entrainment, whereas the fenestrated-tip had partial entrainment in 90% and 87% of the over-pumping and hypovolemic studies, respectively. We conclude that future pediatric VAD designs may benefit from incorporating the parabolic-tip inflow cannula design to maximize unloading of the left ventricle in ideal and nonoptimal conditions.

  18. Diversity assessment of heat resistance of Listeria monocytogenes strains in a continuous-flow heating system.

    Science.gov (United States)

    van der Veen, Stijn; Wagendorp, Arjen; Abee, Tjakko; Wells-Bennik, Marjon H J

    2009-05-01

    Listeria monocytogenes is a foodborne pathogen that has the ability to survive relatively high temperatures compared with other nonsporulating foodborne pathogens. This study was performed to determine whether L. monocytogenes strains with relatively high heat resistances are adequately inactivated in a high-temperature, short-time pasteurization process (72 degrees C for 15 s). To obtain heat-resistant strains, 48 strains were exposed to 55 degrees C for up to 3 h. The energy of activation constant and inactivation constant of strains that survived best (strains 1E and NV8) were subsequently determined in a continuous-flow-through system. Strain Scott A was taken along as a reference. The 3 strains were cultured in whole milk and in brain heart infusion broth at 30 and 7 degrees C. Strains 1E and NV8 were significantly more heat resistant than was strain Scott A after growth in brain heart infusion broth at 30 degrees C and after growth in milk at 7 degrees C. From the inactivation parameters, it was calculated that exposure to high-temperature, short-time pasteurization (72 degrees C for 15 s) will result in 12.1-, 14.2-, and 87.5-log reductions for the strains 1E, NV8, and Scott A, respectively. These results demonstrate that industrial pasteurization conditions suffice to inactivate the most heat-resistant L. monocytogenes strains tested in this study.

  19. Continuous-flow combined process of nitritation and ANAMMOX for treatment of landfill leachate.

    Science.gov (United States)

    Wang, Zhong; Peng, Yongzhen; Miao, Lei; Cao, Tianhao; Zhang, Fangzhai; Wang, Shuying; Han, Jinhao

    2016-08-01

    Due to the difficulty in removing nitrogen from landfill leachate, a combined continuous-flow process of nitritation and anammox was applied to process mature leachate. The transformation rate of ammonia and nitrite accumulation ratio in A/O reactor were kept above 95% and 92% respectively through associated inhibition of free ammonia (FA) and free nitrous acid (FNA) to NOB. The total nitrogen volumetric load of anammox in an UASB reactor was brought up from 0.5kg/(m(3)·d) to 1.2kg/(m(3)·d) by gradually increasing influent substrate concentration and reducing hydraulic retention time (HRT). The results show that COD from mature leachate did not bring obvious inhibition effects to anammox. Under concentrations of influent ammonia and COD which were respectively 1330mg/L and 2250mg/L, the removal efficiencies of TN and COD reached 94% and 62% respectively. In the quantitative PCR reactions, the proportions occupied by AOB, NOB and anammox in A/O were 11.39%, 1.76% and 0.05% respectively; and proportions of those in UASB were 0.35%, 4.01% and 7.78% respectively. PMID:27176671

  20. Device-Related Thrombosis in Continuous-Flow Left Ventricular Assist Device Support.

    Science.gov (United States)

    Doligalski, Christina Teeter; Jennings, Douglas L

    2016-02-01

    Advanced heart failure therapy has been revolutionized with the advent of continuous-flow ventricular assist devices (CF-LVADs) which have improved both survival and quality of life. Despite this, support with CF-LVADs is frequently complicated, with 70% of recipients experiencing a major complication in the first year of durable support. The most concerning of these complications to emerge is device-related thrombosis, which is associated with increased morbidity and mortality. Pathophysiology and diagnosis are multifaceted and complex, with pump-specific and patient-specific factors to be considered. Incidence estimates are evolving with increases seen in the past 2 years compared with earlier implant data. Evidence for treatment is limited to case series and reports, which are subject to significant publication bias. Finally, appropriate primary and secondary prophylaxis is imprecise with multiple antiplatelet and antithrombotic strategies described. This review seeks to summarize the current literature surrounding the pathophysiology, diagnosis, and management of thrombosis in CF-LVAD recipients.

  1. Formaldehyde degradation by UV/TiO2/O3 process using continuous flow mode

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The degradation of formaldehyde gas was studied using UV/TiO2/O3 process under the condition of continuous flow mode.The effects of humidity,initial formaldehyde concentration,residence time and ozone adding amount on degradation of formaldehyde gas were investigated.The experimental results indicated that the combination of ozonation with photocatalytic oxidation on the degradation of formaldehyde showed a synergetic action,e.g.,it could considerably increase decomposing of formaldehyde.The degradation efficiency of formaldehyde was between 73.6% and 79.4% while the initial concentration in the range of 1.84-24 mg/m3 by O3/TiO2/UV process.The optimal humidity was about 50% in UV/TiO2/O3 processs and degradation of formaldehyde increases from 39.0% to 94.1% when the ozone content increased from 0 to 141 mg/m3.Furthermore.the kinetics of formaldehyde degradation coefficient K of 0.0268 m3/mg were obtained.

  2. Use of continuous flow erythrocytapheresis in pregnant patients with sickle cell disease.

    Science.gov (United States)

    Morrison, J C; Morrison, F S; Floyd, R C; Roberts, W E; Hess, L W; Wiser, W L

    1991-01-01

    The role of partial prophylactic red cell exchange transfusion in the management of pregnant patients with major sickle hemoglobinopathies is unclear. Over a 10-year period, 131 pregnant patients with major hemoglobinopathies (HbS 101, HbS-C 30) were managed by the same group of physicians. Of these, 103 received partial prophylactic exchange transfusion early during prenatal care while 28 received blood only when serious complications developed (control group). Patients treated with exchange transfusion received continuous flow erythrocytapheresis on an outpatient basis. The results indicate that there were fewer crises (P = .0001), a reduction in other significant medical complications (P = .002), and a decrease in maternal hospital days (P = .05) in those receiving prophylactic transfusions compared to women in the control group. The number of preterm deliveries (P = .004), the prevalence of low birthweight infants (P = .01), and the perinatal death rate (P = .01) were significantly lower among those who were routinely transfused. Two patients developed hepatitis, five had transfusion reactions, and 11 were found to have alloantibodies among those receiving prophylactic transfusions versus one, two, and five patients, respectively, in the control group. The results indicate a benefit of this methodology in the treatment of pregnant sickle cell patients in our population. However, a national collaborative randomized study is needed to adequately address the controversy regarding the use of red cell exchange in the pregnant sickler. PMID:1816244

  3. Bioprocessing in Microgravity: Applications of Continuous Flow Electrophoresis to Rat Anterior Pituitary Particles

    Science.gov (United States)

    Hymer, W. C.; Salada, T.; Cenci, R.; Krishnan, K.; Seaman, G. V. F.; Snyder, R.; Matsumiya, H.; Nagaoka, S.

    1996-01-01

    In this report we describe the results of a continuous flow electrophoresis (CFE) experiment done on STS-65 in which we tested the idea that intracellular growth hormone (GH) particles contained in a cell lysate prepared from cultured rat anterior pituitary cells in microgravity might have different electrophoretic mobilities from those in a synchronous ground control cell lysate. Collectively, the results suggested that CFE processing in microgravity was better than on earth; more samples could be processed at a time (6 x) and more variant forms of GH molecules could be resolved as well. We had also hoped to carry out a pituitary cell CFE experiment, but failure of the hardware required that the actual cell electrophoresis trials be done on earth shortly after Shuttle landing. Data from these experiments showed that space-flown cells possessed a higher electrophoretic mobility than ground control cells, thereby offering evidence for the idea that exposure of cultured cells to microgravity can change their net surface charge-density especially when the cells are fed. Collectively, the results from this pituitary cell experiment document the advantage of using coupled cell culture and CFE techniques in the microgravity environment.

  4. Continuous-flow hydrothermal synthesis for the production of inorganic nanomaterials.

    Science.gov (United States)

    Dunne, Peter W; Munn, Alexis S; Starkey, Chris L; Huddle, Tom A; Lester, Ed H

    2015-12-28

    As nanotechnology becomes increasingly important and ubiquitous, new and scalable synthetic approaches are needed to meet the growing demand for industrially viable routes to nanomaterial production. Continuous-flow hydrothermal synthesis or supercritical water hydrothermal synthesis (scWHS) is emerging as a versatile solution to this problem. The process was initially developed to take advantage of the tunable chemical and physical properties of superheated water to produce metal oxide nanoparticles by rapid nucleation and precipitation. The development of new mixing regimes and reactor designs has been facilitated by the modelling of reactor systems. These new reactor designs further exploit the properties of supercritical water to promote faster and more uniform mixing of reagent streams. The synthetic approach has been expanded beyond the metal oxide systems for which it was conceived, and now encompasses metal sulfides, metal phosphates, metal nanoparticles and metal-organic frameworks. In many of these cases, some degree of size and shape control can be achieved through careful consideration of both chemistry and reactor design. This review briefly considers the development of scWHS reactor technology, before highlighting some of our recent work in expanding the scope of this synthetic method to include a wide range of materials. PMID:26574533

  5. Grain drying in a continuous flow drier supplemented with a microwave heating system

    International Nuclear Information System (INIS)

    Field losses of wheat grain and sprouting can be reduced by harvesting at higher moisture content than is currently practised. When drying from high moisture content the throughput of continuous flow driers can be increased by preheating the grain at the inlet into the drier, using a microwave heating system. A simulation model was developed to establish the performance and the cost of drying for such a system. The effect of the specific costs of the microwave source, electricity and fuel on the overall cost of drying were investigated. Sensitivity analyses were carried out for drying air temperatures in the range 50 to 90°C and for initial grain moisture contents of 16% to 24% w.b. (wet basis). The most critical factors affecting the cost of drying were the specific costs of the microwave source, electricity and fossil fuel. With the present costs of fuel and electricity of around 0·05 Australian dollars per kWh, the maximum economically viable cost of the microwave component of the drying system is 480 $/kW. The highest saving on the cost of drying was achieved when a microwave-supplemented drier operated at an air temperature of about 75°C and dired 150 t/d, reducing grain moisture from 18% w.b. to 12% w.b

  6. Performance evaluation of a continuous flow inclined solar still desalination system

    International Nuclear Information System (INIS)

    Highlights: • A mathematical model was presented to analyze the performance of inclined still. • The effect of air speed, water masses, film thickness and velocity was studied. • Productivity for the Model 3 was higher than conventional still by 57.2%. • The performance was strongly affected by water film thickness and velocity. • Model 3 gave the highest performance while Model 1 gave the lowest performance. - Abstract: In the present work, theoretical study of the performance evaluation of a continuous water flow inclined solar still desalination system is performed. Three models are studied for inclined solar still desalination system with and without water close loop. The effects of the water mass, water film thickness, water film velocity and air wind velocity on the performance of the three models are studied. The results show that the inclined solar still with a makeup water is superior in productivity (57.2% improvement) compared with a conventional basin-type solar still. Also, the application of inclined solar still with open water loop is recommended when combined with other still desalination system due to high water temperature output. The inclined solar still with a makeup (Model 3) gives the highest performance while Model 1 gives the lowest performance. Finally, the water film thickness, and velocity as well as wind velocity plays important roles in improving the still productivity and efficiency

  7. Formaldehyde degradation by UV/TiO2/O3 process using continuous flow mode.

    Science.gov (United States)

    Qi, Hong; Sun, De-Zhi; Chi, Guo-Qing

    2007-01-01

    The degradation of formaldehyde gas was studied using UV/TiO2/O3 process under the condition of continuous flow mode. The effects of humidity, initial formaldehyde concentration, residence time and ozone adding amount on degradation of formaldehyde gas were investigated. The experimental results indicated that the combination of ozonation with photocatalytic oxidation on the degradation of formaldehyde showed a synergetic action, e.g., it could considerably increase decomposing of formaldehyde. The degradation efficiency of formaldehyde was between 73.6% and 79.4% while the initial concentration in the range of 1.84-24 mg/m3 by O3/TiO2/UV process. The optimal humidity was about 50% in UV/TiO2/O3 processs and degradation of formaldehyde increases from 39.0% to 94.1% when the ozone content increased from 0 to 141 mg/m3. Furthermore, the kinetics of formaldehyde degradation reaction could be described by Langmuir-Hinshelwood model. The rate constant k of 46.72 mg/(m3 x min) and Langmuir adsorption coefficient K of 0.0268 m3/mg were obtained.

  8. Operating parameters of liquid helium transfer lines used with continuous flow cryostats at low sample temperatures

    Science.gov (United States)

    Dittmar, N.; Welker, D.; Haberstroh, Ch; Hesse, U.; Krzyzowski, M.

    2015-12-01

    Continuous flow cryostats are used to cool samples to a variable temperature level by evaporating a cryogen, e.g. liquid helium (LHe). For this purpose LHe is usually stored outside the cryostat in a mobile dewar and supplied through a transfer line. In general, the complete setup has to be characterised by the lowest possible consumption of LHe. Additionally, a minimum sample temperature can be favourable from an experimental point of view. The achievement of both requirements is determined by the respective cryostat design as well as by the transfer line. In the presented work operating data, e.g. the LHe consumption during cooldown and steady state, the minimum sample temperature, and the outlet quality are analysed to characterise the performance of a reference transfer line. In addition, an experimental transfer line with built-in pressure sensors has been commissioned to examine the pressure drop along the transfer line, too. During the tests LHe impurities occurred which restricted a steady operation.

  9. HEAT TRANSFER IN THREE DIMENSIONAL MHD BOUNDARY LAYER FLOW OVER A CONTINUOUS POROUS SURFACE MOVING IN A PARALLEL FREE STREAM

    OpenAIRE

    KHEM CHAND

    2011-01-01

    The heat transfer and hydromagnetic boundary layer flow of an electrically conducting viscous ,incompressible fluid over a continuous flat surface moving in a parallel free stream is investigated. The porous infinite surface is subjected to a slightly sinusoidal transverse suction velocity distribution. The flow becomes three dimensional due to this type of suction velocity without taking into account the induced magnetic field; the mathematical analysis is presented for the hydromagnetic lam...

  10. Rapid and efficient copper-catalyzed Finkelstein reaction of (hetero)aromatics under continuous-flow conditions.

    Science.gov (United States)

    Chen, Mao; Ichikawa, Saki; Buchwald, Stephen L

    2015-01-01

    A general, rapid, and efficient method for the copper-catalyzed Finkelstein reaction of (hetero)aromatics has been developed using continuous flow to generate a variety of aryl iodides. The described method can tolerate a broad spectrum of functional groups, including N-H and O-H groups. Additionally, in lieu of isolation, the aryl iodide solutions were used in two distinct multistep continuous-flow processes (amidation and Mg-I exchange/nucleophilic addition) to demonstrate the flexibility of this method.

  11. Effect of electromagnetic swirling flow in slide-gate SEN on flow field in square billet continuous casting mold

    Institute of Scientific and Technical Information of China (English)

    Dianqiao GENG; Hong LEI; Jicheng HE; Haitao LIU

    2012-01-01

    In order to weaken the bias flow in the submerged entry nozzle (SEN) with slidegate,the rotating magnetic field was imposed.The numerical method was employed to investigate the effect of rotating magnetic field on the flow field in the SEN and the mold under different slide-gate opening ratios.Numerical results showed that when the slide-gate opening ratio is smaller than 100%,the flow field in the SEN and the mold become asymmetry and there is an obvious circulation under the slidegate in the SEN.With increasing exciting current,the divergent angle of liquid steel at the SEN outlet increases,the impact depth of liquid steel in the mold decreases.With increasing slide-gate opening ratio,the impact depth of liquid steel in the mold increases and the required exciting current to weaken the bias flow should increase.

  12. A discussion of the bi-directional ranking of occurrence-frequency based non-interactive literature method for knowledge discovery

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Yunqiu; GUO; Kelei

    2009-01-01

    Based on the analysis of the existing ranking terminology or subject relevancy of documents methods through an intermediary collection as a catalyst(designated as Group B collection)for the purpose of of non-interactive literature-based discovery,this article proposes a bi-directional document occurrence frequency based ranking method according to the"concurrence theory"and the degree and extent of the subject relevancy.This method explores and further refines the ranking method that is based on the occurrence frequency of the usage of certain terminologies and documents and injects a new insightful perspective of the concurrence of appropriate terminologies/documents in the"low occurrence frequency component"of three non-interactive document collections.A preliminary experiment was conducted to analyze and to test the significance and viability of our newly designed operational method.

  13. A validation of a ray-tracing tool used to generate bi-directional scattering distribution functions for complex fenestration systems

    DEFF Research Database (Denmark)

    McNeil, A.; Jonsson, C.J.; Appelfeld, David;

    2013-01-01

    for arbitrary fenestration systems could only be produced using either expensive software or with expensive equipment. genBSDF outputs CFS data in the Window 6 XML file format and so can be used with CFS-enabled software tools to model multi-layered window systems composed of glazing and shading layers......Fenestration attachments are anticipated to produce significant reductions in building energy use because they can be deployed quickly at low-cost. New software tools enable users to assess the building energy impacts of optically complex fenestration systems (CFS) such as shades, Venetian blinds......, or daylighting systems. However, such tools require users to provide bi-directional scattering distribution function (BSDF) data that describe the solar-optical performance of the CFS. A free, open-source Radiance tool genBSDF enables users to generate BSDF data for arbitrary CFS. Prior to genBSDF, BSDF data...

  14. Performance Assessment of Bi-Directional Knotless Tissue-Closure Devices in Juvenile Chinook Salmon Surgically Implanted with Acoustic Transmitters, 2009 - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Woodley, Christa M.; Wagner, Katie A.; Bryson, Amanda J.

    2012-11-09

    The purpose of this report is to assess the performance of bi-directional knotless tissue-closure devices for use in tagging juvenile salmon. This study is part of an ongoing effort at Pacific Northwest National Laboratory (PNNL) to reduce unwanted effects of tags and tagging procedures on the survival and behavior of juvenile salmonids, by assessing and refining suturing techniques, suture materials, and tag burdens. The objective of this study was to compare the performance of the knotless (barbed) suture, using three different suture patterns (treatments: 6-point, Wide “N”, Wide “N” Knot), to the current method of suturing (MonocrylTM monofilament, discontinuous sutures with a 2×2×2×2 knot) used in monitoring and research programs with a novel antiseptic barrier on the wound (“Second Skin”).

  15. Cultivation of methanogenic community from 2-km deep subseafloor coalbeds using a continuous-flow bioreactor

    Science.gov (United States)

    Imachi, H.; Tasumi, E.; Morono, Y.; Ito, M.; Takai, K.; Inagaki, F.

    2013-12-01

    Deep subseafloor environments associated with hydrocarbon reservoirs have been least explored by previous scientific drilling and hence the nature of deep subseafloor life and its ecological roles in the carbon cycle remain largely unknown. In this study, we performed cultivation of subseafloor methanogenic communities using a continuous-flow bioreactor with polyurethane sponges, called down-flow hanging sponge (DHS) reactor. The sample used for the reactor cultivation was obtained from 2 km-deep coalbeds off the Shimokita Peninsula of Japan, the northwestern Pacific, during the Integrated Ocean Drilling Program (IODP) Expedition 337 using a riser drilling technology of the drilling vessel Chikyu. The coalbed samples were incubated anaerobically in the DHS reactor at the in-situ temperature of 40°C. Synthetic seawater supplemented with a tiny amount of yeast extract, acetate, propionate and butyrate was provided into the DHS reactor. After 34 days of the bioreactor operation, a small production of methane was observed. The methane concentration was gradually increased and the stable carbon isotopic composition of methane was consistency 13C-depleted during the bioreactor operation, indicating the occurrence of microbial methanogenesis. Microscopic observation showed that the enrichment culture contained a variety of microorganisms, including methanogen-like rod-shaped cells with F420 auto-fluorescence. Interestingly, many spore-like particles were observed in the bioreactor enrichment. Phylogenetic analysis of 16S rRNA genes showed the growth of phylogenetically diverse bacteria and archaea in the DHS reactor. Predominant archaeal components were closely related to hydrogenotrophic methanogens within the genus Methanobacterium. Some predominant bacteria were related to the spore-formers within the class Clostridia, which are overall in good agreement with microscopic observations. By analyzing ion images using a nano-scale secondary ion mass spectrometry (Nano

  16. A Flow rate of gas versus the level of gas dispersion in physical model of continuous refining reactor

    Directory of Open Access Journals (Sweden)

    M. Saternus

    2015-01-01

    Full Text Available Today there are many reactors used in refining of primary and secondary aluminium. Continuous reactor URC-7000 is one of them. The model of such reactor was built at 1:3 scale. The physical modelling research was conducted taking into account the flow rate of refining gas and its influence of the dispersion level. There are two nozzles introducing a gas. The carried out tests included the different flow rate of a gas through the nozzles (from 5 to 15 dm3/min. Additionally, the mixing characteristics were measured and discussed for different flow rate of an inert gas.

  17. The construction and characterization of the bi-directional promoter between pp38 gene and 1.8-kb mRNA transcripts of Marek's disease viruses

    Directory of Open Access Journals (Sweden)

    Ding Jiabo

    2009-11-01

    Full Text Available Abstract Background Marek's disease virus (MDV has a bi-directional promoter between pp38 gene and 1.8-kb mRNA transcripts. By sequencing for the promoters from 8 different strains (CVI988, 814, GA, JM, Md5, G2, RB1B and 648A, it is found, comparing with the other 7 MDV strains, CVI988 has a 5-bp (from -628 to -632 deletion in this region, which caused a Sp1 site destroyed. In order to analysis the activity of the promoter, the complete bi-directional promoters from GA and CVI988 were, respectively, cloned into pCAT-Basic vector in both directions for the recombinants pPGA(pp38-CAT, pPGA(1.8 kb-CAT, pPCVI(pp38-CAT and pPCVI(1.8 kb-CAT. The complete promoter of GA was divided into two single-direction promoters from the replication of MDV genomic DNA, and cloned into pCAT-Basic for pdPGA(pp38-CAT and pdPGA(1.8 kb-CAT as well. The above 6 recombinants were then transfected into chicken embryo fibroblasts (CEFs infected with MDV, and the activity of chloramphenicol acetyltransferase (CAT was measured from the lysed CEFs 48 h post transfection. Results The results showed the activity of the divided promoters was decreased on both directions. In 1.8-kb mRNA direction, it is nearly down to 2.4% (19/781 of the whole promoter, while it keeps 65% (34/52 activity in pp38 direction. The deletion of Sp1 site in CVI988 causes the 20% activity decreased, and has little influence in pp38 direction. Conclusion The present study confirmed their result, and the promoter for the 1.8-kb mRNA transcripts is a much stronger promoter than that in the orientation for pp38.

  18. A continuous flow micro filtration device for plasma/blood separation using submicron vertical pillar gap structures

    International Nuclear Information System (INIS)

    This work demonstrates a continuous flow plasma/blood separator using a vertical submicron pillar gap structure. The working principle of the proposed separator is based on size exclusion of cells through cross-flow filtration, in which only plasma is allowed to pass through submicron vertical pillars located tangential to the main flow path of the blood sample. The maximum filtration efficiency of 99.9% was recorded with a plasma collection rate of 0.67 µl min−1 for an input blood flow rate of 12.5 µl min−1. The hemolysis phenomenon was observed for an input blood flow rate above 30 µl min−1. Based on the experimental results, we can conclude that the proposed device shows potential for the application of on-chip plasma/blood separation as a part of integrated point-of-care (POC) diagnostics systems. (technical note)

  19. Romanian wines characterization with CF-IRMS (Continuous Flow Isotope Ratio Mass Spectrometry) isotopic analysis

    International Nuclear Information System (INIS)

    Wine growing has been known for centuries long in Romania. The country has been favored by its geographical position in south-eastern Europe, by its proximity to the Black Sea, as well as by the specificity of the local soil and climate. Alongside France, Italy, Spain, Germany, countries in this area like Romania could also be called 'a vine homeland' in Europe. High quality wines produced in this region were object of trade ever since ancient times. Under current EU research projects, it is necessary to develop new methods of evidencing wine adulteration and safety. The use of mass spectrometry (MS) to determine the ratios of stable isotopes in bio-molecules now provides the means to prove the botanical and geographical origin of a wide variety of foodstuffs - and therefore, to authenticate and eliminate fraud. Isotope analysis has been officially adopted by the EU as a means of controlling adulteration of wine. Adulteration of wine can happen in many ways, e.g. addition of non-grape ethanol, addition of non-grape sugar, water or other unauthorized substances, undeclared mixing of wines from different wards, geographical areas or countries, mislabelling of variety and age. The present paper emphasize the isotopic analysis for D/H, 18O/16O, 13C/12C from wines, using a new generation Isotope Ratio MS, Finnigan Delta V Plus, coupling with a three flexible continuous flow preparation device (GasBench II, TC Elemental Analyser and GC-C/TC). Therefore authentication of wines is an important problem to which isotopic analysis has made a significant contribution. (authors)

  20. Thrombosis in continuous-flow left ventricular assist devices: pathophysiology, prevention, and pharmacologic management.

    Science.gov (United States)

    Jennings, Douglas L; Weeks, Phillip A

    2015-01-01

    Continuous-flow left ventricular assist devices reduce short-term mortality and improve quality of life in patients with end-stage heart failure. Unfortunately, device-related complications remain common, with many patients experiencing adverse events within the first year. New literature suggests that rates of device-related thrombosis may be increasing since 2011, which is particularly troublesome given that this pathology can result in a disabling stroke, organ damage, and death. In 2013, a group of practitioners in the field of mechanical circulatory support published a treatment algorithm based on their expert opinion. However, a comprehensive review of the pharmacotherapy of this condition is lacking. A search of the literature revealed 20 separate publications of case reports or case series describing outcomes associated with the use of drug therapy for suspected pump thrombosis. Each of these experiences was limited by small sample size, nonrandomized treatment allocation, and nonstandardized medication dosing. Data describing the outcomes of surgical versus medical management of device thrombosis are also sparse, with only three published reports identified. Based on the review of this limited literature, surgical management appears to be the preferred treatment modality, especially in those with organ hypoperfusion or hemodynamic instability. In patients ineligible for surgery, pharmacotherapy options remain limited. Use of all drug classes described in the literature for the HeartMate II device-fibrinolytics, glycoprotein IIb/IIIa inhibitors, and direct thrombin inhibitors-was hindered by either marginal efficacy or bleeding. Based on historical experience with unfractionated heparin in patients under HeartMate II support, we recommend this agent as a possible option for those with suspected pump thrombosis in lieu of surgical device exchange. For the HeartWare HVAD, limited data suggest that direct intraventricular administration of alteplase may be an

  1. Switchgrass (Panicum virgatum fermentation by Clostridium thermocellum and Clostridium saccharoperbutylacetonicum sequential culture in a continuous flow reactor

    Directory of Open Access Journals (Sweden)

    Noelia M. Elía

    2016-01-01

    Full Text Available The study was conducted to evaluate fermentation by Clostridium thermocellum and C. saccharoperbutylacetonicum in a continuous-flow, high-solids reactor. Liquid medium was continuously flowed through switchgrass (2 mm particle size at one of three flow rates: 83.33 mL h−1 (2 L d−1, 41.66 mL h−1 (1 L d−1, and 20.833 mL h−1 (0.5 L d−1. The cellulolytic phase was initiated by culturing C. thermocellum (63 °C, 24 h. The temperature was decreased (35 and C. saccharoperbutylacetonicum was inoculated. When metabolism decreased (96 h, the temperature was increased (63 °C; 24 h to permit cellulosome production by C. thermocellum. The C. saccharoperbutylacetonicum was re-inoculated and the temperature returned to 35°C. The average gross production over 9 d was 1480 mg total acids (formic, acetic lactic butyric, 207 mg total solvents (acetone, butanol, ethanol, and average dry matter disappearance was 2.8 g from 25 g non-pretreated switchgrass. There was no effect of flow rate on the product formation. These results indicate that C. thermocellum can survive and produce cellulases with C. saccharoperbutylacetonicumin a continuous-flow, high-solids reactor temperature with temperature cycling.

  2. Palladium on Carbon-Catalyzed Suzuki-Miyaura Coupling Reaction Using an Efficient and Continuous Flow System

    Directory of Open Access Journals (Sweden)

    Tomohiro Hattori

    2015-01-01

    Full Text Available The continuous flow Suzuki-Miyaura reaction between various haloarenes and arylboronic acids was successfully achieved within only ca. 20 s during the single-pass through a cartridge filled with palladium on carbon (Pd/C. No palladium leaching was observed in the collected reaction solution by atomic absorption spectrometry (detection limit: 1 ppm.

  3. BIOTRANSFORMATION OF 2,4,6-TRINITROTOLUENE IN A CONTINUOUS-FLOW ANABAENA SP. SYSTEM. (R825513C013)

    Science.gov (United States)

    Reductive transformation of 2,4,6-trinitrotoluene (TNT) was observed in a continuous-flow system of Anabaena sp. operated for 33 d with a 5.7 d hydraulic retention time and a range of influent TNT concentrations of 1–58 mg/l. The TNT removal effici...

  4. Continuous-flow isotope ratio mass spectrometry method for carbon and hydrogen isotope measurements on atmospheric methane

    NARCIS (Netherlands)

    Brass, M.; Roeckmann, T.

    2010-01-01

    We describe a continuous-flow isotope ratio mass spectrometry (CF-IRMS) technique for high-precision δD and δ13C measurements of atmospheric methane on 40 mL air samples. CH4 is separated from other air components by utilizing purely physical processes based on temperature, time and mechanical valve

  5. 42 CFR 84.162 - Man test for gases and vapors; Type C respirators, continuous-flow class and Type CE supplied-air...

    Science.gov (United States)

    2010-10-01

    ..., continuous-flow class and Type CE supplied-air respirators; test requirements. 84.162 Section 84.162 Public....162 Man test for gases and vapors; Type C respirators, continuous-flow class and Type CE supplied-air... acetate-free air. (b) The minimum flow of air required to maintain a positive pressure in the...

  6. Continuous Flow Polymer Synthesis toward Reproducible Large-Scale Production for Efficient Bulk Heterojunction Organic Solar Cells.

    Science.gov (United States)

    Pirotte, Geert; Kesters, Jurgen; Verstappen, Pieter; Govaerts, Sanne; Manca, Jean; Lutsen, Laurence; Vanderzande, Dirk; Maes, Wouter

    2015-10-12

    Organic photovoltaics (OPV) have attracted great interest as a solar cell technology with appealing mechanical, aesthetical, and economies-of-scale features. To drive OPV toward economic viability, low-cost, large-scale module production has to be realized in combination with increased top-quality material availability and minimal batch-to-batch variation. To this extent, continuous flow chemistry can serve as a powerful tool. In this contribution, a flow protocol is optimized for the high performance benzodithiophene-thienopyrroledione copolymer PBDTTPD and the material quality is probed through systematic solar-cell evaluation. A stepwise approach is adopted to turn the batch process into a reproducible and scalable continuous flow procedure. Solar cell devices fabricated using the obtained polymer batches deliver an average power conversion efficiency of 7.2 %. Upon incorporation of an ionic polythiophene-based cathodic interlayer, the photovoltaic performance could be enhanced to a maximum efficiency of 9.1 %. PMID:26388210

  7. Continuous Flow Polymer Synthesis toward Reproducible Large-Scale Production for Efficient Bulk Heterojunction Organic Solar Cells.

    Science.gov (United States)

    Pirotte, Geert; Kesters, Jurgen; Verstappen, Pieter; Govaerts, Sanne; Manca, Jean; Lutsen, Laurence; Vanderzande, Dirk; Maes, Wouter

    2015-10-12

    Organic photovoltaics (OPV) have attracted great interest as a solar cell technology with appealing mechanical, aesthetical, and economies-of-scale features. To drive OPV toward economic viability, low-cost, large-scale module production has to be realized in combination with increased top-quality material availability and minimal batch-to-batch variation. To this extent, continuous flow chemistry can serve as a powerful tool. In this contribution, a flow protocol is optimized for the high performance benzodithiophene-thienopyrroledione copolymer PBDTTPD and the material quality is probed through systematic solar-cell evaluation. A stepwise approach is adopted to turn the batch process into a reproducible and scalable continuous flow procedure. Solar cell devices fabricated using the obtained polymer batches deliver an average power conversion efficiency of 7.2 %. Upon incorporation of an ionic polythiophene-based cathodic interlayer, the photovoltaic performance could be enhanced to a maximum efficiency of 9.1 %.

  8. Continuous positive airway pressure alters cranial blood flow and cerebrospinal fluid dynamics at the craniovertebral junction

    Directory of Open Access Journals (Sweden)

    Theresia I. Yiallourou

    2015-09-01

    Conclusion: Application of CPAP via a full-fitted mask at 15 cm H2O was found to have a significant effect on intracranial venous outflow and spinal CSF flow at the C2 vertebral level in healthy adult-age awake volunteers. CPAP can be used to non-invasively provoke changes in intracranial and CSF flow dynamics.

  9. Biogeochemistry of Hydrothermal Chimney Environments: Continuous-Flow Experiments at in situ Temperature and Pressure

    Science.gov (United States)

    Houghton, J.; Seyfried, W.; Reysenbach, A.; Banta, A.; von Damm, K.

    2002-12-01

    Recent interest in the existence of a subsurface microbial biosphere at hydrothermal vents has resulted in a plethora of new questions that might best be answered using interdisciplinary techniques that combine geochemistry, microbial ecology, and molecular biology. Ideally, such studies will quantitatively address issues concerning what organisms exist in the subsurface, what metabolisms are sustained in the hydrothermal environment, and what effects these active organisms might have on the nearby fluid and rock. We present a new experimental approach to studying these questions that enables monitoring of an active hydrothermal community of microbes in the presence of chimney material at in situ temperature and pressure. This apparatus is designed as a continuous-flow reactor from which fluid samples can be extracted during the course of the experiment to measure chemistry and biomass, and at the termination of an experiment solids can be extracted for analysis of mineralogical changes and microbial identification. Results of a series of experiments conducted using hydrothermal chimney material (solids and microbial community) collected from 21° N and 9° N East Pacific Rise are presented. At 70° C, a seawater-based fluid with additional NO3-, CO2(aq), and H2(aq) was reacted with chimney material from L vent, 9° N EPR. The fluid lost significant NO3-, PO43-, and gained SO42- even after accounting for the contribution from anhydrite dissolution. No significant sulfide or iron was observed in the fluid. Analysis of the DNA extracted from the solids at the termination of the experiment using partial 16S-rRNA sequence data revealed that the dominant bacteria were S-oxidizing tube worm endosymbionts, a S/NO3- reducing member of the Deferribacter genus, and a H2-oxidizing/NO3- reducing strain of Aquifex. Mineral analysis from before and after the experiment indicates the loss of pyrrhotite (FeS) and anhydrite (CaSO4), and the gain of an Fe-oxide phase tentatively

  10. Continuous flow hydride generation-atomic fluorescence spectrometric determination and speciation of arsenic in wine

    International Nuclear Information System (INIS)

    Methods for the atomic fluorescence spectrometric (AFS) determination of total arsenic and arsenic species in wines based on continuous flow hydride generation (HG) with atomization in miniature diffusion flame (MDF) are described. For hydride-forming arsenic, L-cysteine is used as reagent for pre-reduction and complexation of arsenite, arsenate, monomethylarsonate and dimethylarsinate. Concentrations of hydrochloric acid and tetrahydroborate are optimized in order to minimize interference by ethanol. Procedure permits determination of the sum of these four species in 5-10-fold diluted samples with limit of detection (LOD) 0.3 and 0.6 μg l-1 As in white and red wines, respectively, with precision between 2% and 8% RSD at As levels within 0.5-10 μg l-1. Selective arsine generation from different reaction media is used for non-chromatographic determination of arsenic species in wines: citrate buffer at pH 5.1 for As(III); 0.2 mol l-1 acetic acid for arsenite + dimethylarsinate (DMA); 8 mol l-1 HCl for total inorganic arsenic [As(III) + As(V)]; and monomethylarsonate (MMA) calculated by difference. Calibration with aqueous and ethanol-matched standard solutions of As(III) is used for 10- and 5-fold diluted samples, respectively. The LODs are 0.4 μg l-1 for As(III) and 0.3 μg l-1 for the other three As species and precision is within 4-8% RSDs. Arsenic species in wine were also determined by coupling of ion chromatographic separation on an anion exchange column and HG-flame AFS detection. Methods were validated by means of recovery studies and comparative analyses by HG-AFS and electrothermal atomic absorption spectrometry after microwave digestion. The LODs were 0.12, 0.27, 0.15 and 0.13 μg l-1 (as As) and RSDs were 2-6%, 5-9%, 3-7% and 2-5% for As(III), As(V), MMA and DMA arsenic species, respectively. Bottled red and white wines from Bulgaria, Republic of Macedonia and Italy were analyzed by non-chromatographic and chromatographic procedures and the As

  11. Continuous-Flow Synthesis and Materials Interface Engineering of Lead Sulfide Quantum Dots for Photovoltaic Applications

    KAUST Repository

    El-Ballouli, Ala’a O.

    2016-05-25

    Harnessing the Sun’s energy via the conversion of solar photons to electricity has emerged as a sustainable energy source to fulfill our future demands. In this regard, solution-processable, size-tunable PbS quantum dots (QDs) have been identified as a promising active materials for photovoltaics (PVs). Yet, there are still serious challenges that hinder the full exploitation of QD materials in PVs. This dissertation addresses two main challenges to aid these QDs in fulfilling their tremendous potential in PV applications. First, it is essential to establish a large-scale synthetic technique which maintains control over the reaction parameters to yield QDs with well-defined shape, size, and composition. Rigorous protocols for cost-effective production on a scale are still missing from literature. Particularly, previous reports of record-performance QD-PVs have been based on small-scale, manual, batch syntheses. One way to achieve a controlled large-scale synthesis is by reducing the reaction volume to ensure uniformity. Accordingly, we design a droplet-based continuous-flow synthesis of PbS QDs. Only upon separating the nucleation and growth phases, via a dual-temperature-stage reactor, it was possible to achieve high-quality QDs with high photoluminescence quantum yield (50%) in large-scale. The performance of these QDs in a PV device was comparable to batch-synthesized QDs, thus providing a promise in utilizing automated synthesis of QDs for PV applications. Second, it is crucial to study and control the charge transfer (CT) dynamics at QD interfaces in order to optimize their PV performance. Yet, the CT investigations based on PbS QDs are limited in literature. Here, we investigate the CT and charge separation (CS) at size-tunable PbS QDs and organic acceptor interfaces using a combination of femtosecond broadband transient spectroscopic techniques and steady-state measurements. The results reveal that the energy band alignment, tuned by the quantum

  12. Fluid Flow and Interfacial Phenomenon of Slag and Metal in Continuous Casting Tundish With Argon Blowing

    Institute of Scientific and Technical Information of China (English)

    WANG Jun; ZHU Miao-yong; ZHOU Hai-bing; WANG Ying

    2008-01-01

    The fluid flow and the interracial phenomenon of slag and metal in tundish with gas blowing were studied with mathematical and physical modeling,and the effects of gas flowrate,the placement of porous beam for the generation of bubbles,and the combination of flow control devices on the flow and slag-metal interface were investigated.The results show that the position of gas bubbling has a significant effect on the flow in tundish,and the placement of porous beam and gas flowrate are the two main factors affecting the entrapment of slag in tundish.The closer the porous beam to the weir,the more reasonable is the flow,which is in favor of the control of slag entrapment in tundish.

  13. Numerical Investigation of the Fluid Flow in Continuous Casting Tundish Using Analysis of RTD Curves

    Institute of Scientific and Technical Information of China (English)

    Moumtez Bensouici; Ahmed Bellaouar; Kamel Tal-bi

    2009-01-01

    A detailed mathematical procedure of the optimization of the fluid flow in a tundish water model with and without flow control devices (weir and dam) was carried out using the commercial CFD code FLUENT 6.0. The (k-ε) two-equation model was used to model turbulence. The residence time distribution (RTD) curves were used to an-alyze the behavior of the flow in tundish. The location of flow control devices in the tundish was studied. The results show that the flow modifiers play an important role in promoting the floatation of nonmetallic inclusions in steel. Comparing the three geometric configurations that are considered (bare tundish, weir, weir+dam), the tundish equipped with the arrangement (weir+dam) is a best and optimal geometric configuration of tundish.

  14. Large Eddy Simulation of Transient Flow and Inclusions Transport in Continuous Casting Mold under Different Electromagnetic Brakes

    Science.gov (United States)

    Liu, Zhongqiu; Li, Linmin; Li, Baokuan

    2016-08-01

    A mathematical model has been developed to analyze transient fluid flow and inclusions transport in a slab continuous casting mold, considering the effects of electromagnetic brake (EMBr) arrangement and magnetic field strength. Transient flow of molten steel in the mold is calculated by using the large eddy simulation. The electromagnetic force is incorporated into the Navier-Stokes equation. The transport of inclusion inside the mold is calculated using the Lagrangian approach based on the transient flow field. The predicted results of this model are compared with the measurements of the ultrasonic testing of the rolled steel plates and the water model experiments. The transient asymmetrical flow pattern and inclusion transport inside the mold exhibits satisfactory agreement with the corresponding measurements. With electromagnetic brake effect, the velocities around the braking region are significantly suppressed, and the recirculating flow in the lower part drops and tends to develop a plug-like flow. The EMBr arrangement has an insignificant effect on the overall removal fraction of inclusions, especially for larger inclusions. The inclusion removal rate for the flow-control mold (FCM arrangement) reduces instead compared with no EMBr, especially for smaller inclusions.

  15. 3D-printed devices for continuous-flow organic chemistry

    OpenAIRE

    Vincenza Dragone; Victor Sans; Rosnes, Mali H; Kitson, Philip J.; Leroy Cronin

    2013-01-01

    We present a study in which the versatility of 3D-printing is combined with the processing advantages of flow chemistry for the synthesis of organic compounds. Robust and inexpensive 3D-printed reactionware devices are easily connected using standard fittings resulting in complex, custom-made flow systems, including multiple reactors in a series with in-line, real-time analysis using an ATR-IR flow cell. As a proof of concept, we utilized two types of organic reactions, imine syntheses and im...

  16. 3D-printed devices for continuous-flow organic chemistry

    Science.gov (United States)

    Dragone, Vincenza; Sans, Victor; Rosnes, Mali H; Kitson, Philip J

    2013-01-01

    Summary We present a study in which the versatility of 3D-printing is combined with the processing advantages of flow chemistry for the synthesis of organic compounds. Robust and inexpensive 3D-printed reactionware devices are easily connected using standard fittings resulting in complex, custom-made flow systems, including multiple reactors in a series with in-line, real-time analysis using an ATR-IR flow cell. As a proof of concept, we utilized two types of organic reactions, imine syntheses and imine reductions, to show how different reactor configurations and substrates give different products. PMID:23766811

  17. 3D-printed devices for continuous-flow organic chemistry

    Directory of Open Access Journals (Sweden)

    Vincenza Dragone

    2013-05-01

    Full Text Available We present a study in which the versatility of 3D-printing is combined with the processing advantages of flow chemistry for the synthesis of organic compounds. Robust and inexpensive 3D-printed reactionware devices are easily connected using standard fittings resulting in complex, custom-made flow systems, including multiple reactors in a series with in-line, real-time analysis using an ATR-IR flow cell. As a proof of concept, we utilized two types of organic reactions, imine syntheses and imine reductions, to show how different reactor configurations and substrates give different products.

  18. 双向非线性隔震支座本构关系模型在双向地震下的动力反应研究%Study on the dynamic response of the constitutional relation models of Bi-directional nonlinear Isolation bearing under the bi-directional earthquake

    Institute of Scientific and Technical Information of China (English)

    杨锦增; 李向真

    2015-01-01

    Based on the constitutional relation models of bi-directional nonlinear isolation bearing,the dynamic equations and calculation methods of single particle isolation system under the bi-directional earthquake are established.The seismic responses of isolation system under various dynamic parameters when meet the rarely met earthquake of 8,8.5 and 9 degree are calculated and analyzed,the rational yield-gravity ratio of lead met the limitation of displacement under various fortified intensity is proposed to provide reliable basis and vector for designing isolation houses.%在双向非线性隔震支座本构关系模型基础上,建立了单质点隔震体系在双向地震作用下的动力方程和计算方法.在8度、8.5度和9度罕遇地震作用下计算分析了隔震体系在各种动力参数下的地震反应,提出了在不同设防烈度下满足位移限制要求的合理纯铅屈重比,为隔震房屋设计提供了可靠的依据和途径.

  19. Thermal management and performance evaluation of a dual bi-directional, soft-switched IGBT-based inverter for the 1st autonomous microgrid power system in Taiwan under various operating conditions

    Science.gov (United States)

    Chang, Tien-Chan; Fuh, Yiin-Kuen; Lu, Hong-Yi; Tu, Sheng-Xun

    2016-06-01

    The thermal management of the inverter system is of great importance since very high voltage/current will be switched intermittently and/or continuously and high temperature is excruciably detrimental to the service life of electronics, especially for the switching devices such as insulated gate bipolar transistor (IGBT). In this study, a newly developed dual bi-directional IGBT-based inverter in conjunction with autonomous microgrid system is investigated with particular focus on the thermal management and performance evaluation under various operation conditions. Locally enhanced heat transfer approach such as oblique orientation and heat dissipating materials are experimentally investigated. The studied inverter system is initially packaged by a galvanized steel plate (size 62 × 48 × 18 cm) and the switching power is set in the range of 0.5-3 kW. The module is operated at the switching and pulse frequencies of 60 Hz and 20 kHz, respectively. The adoption of heat dissipating material in either paste or film form had experimentally shown to possess the flexibility tailoring heat transfer performance locally. Experimental studies of heat dissipating film with various hotspot scenarios showed that the temperature difference can be appreciably reduced as much as 13.1 and 15.4 °C, respectively with facilitation of one- and two-layers of heat dissipating film. From the measurement results, the measured peak temperature is highly dominated by the thickness of heat dissipating film, showing the dominance of thickness-dependent thermal resistance and resultant heat accumulation phenomena.

  20. Segmented continuous-flow multiplex polymerase chain reaction microfluidics for high-throughput and rapid foodborne pathogen detection.

    Science.gov (United States)

    Shu, Bowen; Zhang, Chunsun; Xing, Da

    2014-05-15

    High-throughput and rapid identification of multiple foodborne bacterial pathogens is vital in global public health and food industry. To fulfill this need, we propose a segmented continuous-flow multiplex polymerase chain reaction (SCF-MPCR) on a spiral-channel microfluidic device. The device consists of a disposable polytetrafluoroethylene (PTFE) capillary microchannel coiled on three isothermal blocks. Within the channel, n segmented flow regimes are sequentially generated, and m-plex PCR is individually performed in each regime when each mixture is driven to pass three temperature zones, thus providing a rapid analysis throughput of m×n. To characterize the performance of the microfluidic device, continuous-flow multiplex PCR in a single segmented flow has been evaluated by investigating the effect of key reaction parameters, including annealing temperatures, flow rates, polymerase concentration and amount of input DNA. With the optimized parameters, the genomic DNAs from Salmonella enterica, Listeria monocytogenes, Escherichia coli O157:H7 and Staphylococcus aureus could be amplified simultaneously in 19min, and the limit of detection was low, down to 10(2) copiesμL(-1). As proof of principle, the spiral-channel SCF-MPCR was applied to sequentially amplify four different bacterial pathogens from banana, milk, and sausage, displaying a throughput of 4×3 with no detectable cross-contamination.

  1. Continuous-flow multi-pulse electroporation at low DC voltages by microfluidic flipping of the voltage space topology

    Science.gov (United States)

    Bhattacharjee, N.; Horowitz, L. F.; Folch, A.

    2016-10-01

    Concerns over biosafety, cost, and carrying capacity of viral vectors have accelerated research into physical techniques for gene delivery such as electroporation and mechanoporation. Advances in microfabrication have made it possible to create high electric fields over microscales, resulting in more efficient DNA delivery and higher cell viability. Continuous-flow microfluidic methods are typically more suitable for cellular therapies where a large number of cells need to be transfected under sterile conditions. However, the existing continuous-flow designs used to generate multiple pulses either require expensive peripherals such as high-voltage (>400 V) sources or function generators, or result in reduced cell viability due to the proximity of the cells to the electrodes. In this paper, we report a continuous-flow microfluidic device whose channel geometry reduces instrumentation demands and minimizes cellular toxicity. Our design can generate multiple pulses of high DC electric field strength using significantly lower voltages (15-60 V) than previous designs. The cells flow along a serpentine channel that repeatedly flips the cells between a cathode and an anode at high throughput. The cells must flow through a constriction each time they pass from an anode to a cathode, exposing them to high electric field strength for short durations of time (the "pulse-width"). A conductive biocompatible poly-aniline hydrogel network formed in situ is used to apply the DC voltage without bringing the metal electrodes close to the cells, further sheltering cells from the already low voltage electrodes. The device was used to electroporate multiple cell lines using electric field strengths between 700 and 800 V/cm with transfection efficiencies superior than previous flow-through designs.

  2. Numerical Modeling of the Fluid Flow in Continuous Casting Tundish with Different Control Devices

    Directory of Open Access Journals (Sweden)

    Zhu He

    2013-01-01

    Full Text Available Numerical simulations were conducted to study the melt flow under the influence of control devices in a T-type two-strand bloom caster tundish via the open source Computational Fluid Dynamics software OpenFOAM. Three different cases were studied: a bare tundish, a tundish with two pairs of baffles, and a tundish equipped with a turbulence inhibitor and a pair of baffles. Turbulence inhibitor and baffles arrangement showed an improvement of the fluid flow characteristics, yielding lower values of dead volume and higher values of plug flow. With a turbulence inhibitor, the velocity of metal which flows directly toward the tundish floor is smaller and the turbulence kinetic energy of the melt top surface is lower than the other two arrangements.

  3. 一种改进的基于BiDirectional体制的MISO-SAR系统%Improved MISO-SAR System Based on BiDirectional Imaging

    Institute of Scientific and Technical Information of China (English)

    蒋海; 宋红军

    2015-01-01

    In 2012, the German Aerospace Center (DLR.) proposed a BiDirectional mode that can achieve several seconds of repeated time lags by single star and single flight. Its basic principle includes the generation of a double-beam antenna pattern by electronic beam steering and simultaneous emission of two pulses that irradiate the front and back imaging area. The two pulses, which are simultaneously received will be separated by band-pass filtering in the Doppler domain and imaged, respectively. This paper presents an improved Multi Input Single Output (MISO)-SAR system based on the BiDirectional mode which converts the traditional simultaneous dual beam emitting and receiving into time-division emitting and simultaneous receiving, respectively. This results in an improved emitting antenna pattern owning to the suppression of the Azimuth Ambiguity to Signal Ratio (AASR). The current paper describes the spectrum separation effects, AASR analysis, and the system design process. Therefore, to confirm effectiveness, point target 1-D and 2-D simulation results are compared before and after the improvement. Furthermore, the BiDirectional and other short-term repeated SAR modes are compared.%BiDirectional体制是德宇航在2012年提出的一种通过单星单次飞行实现秒级重访的新体制,基本原理是利用相控阵电扫描方式生成双波束天线方向图,同时发射两个脉冲照射方位向前后两块成像区域,将同时接收到的脉冲在多普勒域进行带通滤波分离,并分别成像。该文介绍了一种改进的基于BiDirectional体制的多发单收(Multi Input Single Output, MISO)SAR系统,将传统的双波束同发同收改进为分时先后发射和同时接收,利用发射时较优的方向图抑制方位模糊(AASR),获得了较好的效果。文中给出了频谱分离效果、AASR分析和系统设计流程,给出了改进前后的点目标1维和2维成像结果对比,证明了该改进的有效性,最后

  4. Bubble Generation in a Continuous Liquid Flow Under Reduced Gravity Conditions

    Science.gov (United States)

    Pais, Salvatore Cezar

    1999-01-01

    The present work reports a study of bubble generation under reduced gravity conditions for both co-flow and cross-flow configurations. Experiments were performed aboard the DC-9 Reduced Gravity Aircraft at NASA Glenn Research Center, using an air-water system. Three different flow tube diameters were used: 1.27, 1.9, and 2.54 cm. Two different ratios of air injection nozzle to tube diameters were considered: 0.1 and 0.2. Gas and liquid volumetric flow rates were varied from 10 to 200 ml/s. It was experimentally observed that with increasing superficial liquid velocity, the bubbles generated decreased in size. The bubble diameter was shown to increase with increasing air injection nozzle diameters. As the tube diameter was increased, the size of the detached bubbles increased. Likewise, as the superficial liquid velocity was increased, the frequency of bubble formation increased and thus the time to detach forming bubbles decreased. Independent of the flow configuration (for either single nozzle or multiple nozzle gas injection), void fraction and hence flow regime transition can be controlled in a somewhat precise manner by solely varying the gas and liquid volumetric flow rates. On the other hand, it is observed that uniformity of bubble size can be controlled more accurately by using single nozzle gas injection than by using multiple port injection, since this latter system gives rise to unpredictable coalescence of adjacent bubbles. A theoretical model, based on an overall force balance, is employed to study single bubble generation in the dynamic and bubbly flow regime. Under conditions of reduced gravity, the gas momentum flux enhances bubble detachment; however, the surface tension forces at the nozzle tip inhibits bubble detachment. Liquid drag and inertia can act either as attaching or detaching force, depending on the relative velocity of the bubble with respect to the surrounding liquid. Predictions of the theoretical model compare well with performed

  5. Beneficial aspects of real time flow measurements for the management of acute right ventricular heart failure following continuous flow ventricular assist device implantation

    Directory of Open Access Journals (Sweden)

    Spiliopoulos Sotirios

    2012-11-01

    Full Text Available Abstract Background Optimal management of acute right heart failure following the implantation of a left ventricular assist device requires a reliable estimation of left ventricular preload and contractility. This is possible by real-time pump blood flow measurements. Clinical case We performed implantation of a continuous flow left ventricular assist device in a 66 years old female patient with an end-stage heart failure on the grounds of a dilated cardiomyopathy. Real-time pump blood flow was directly measured by an ultrasonic flow probe placed around the outflow graft. Diagnosis The progressive decline of real time flow and the loss of pulsatility were associated with an increase of central venous pressure, inotropic therapy and progressive renal failure suggesting the presence of an acute right heart failure. Diagnosis was validated by echocardiography and thermodilution measurements. Treatment Temporary mechanical circulatory support of the right ventricle was successfully performed. Real time flow measurement proved to be a useful tool for the diagnosis and ultimately for the management of right heart failure including the weaning from extracorporeal membrane oxygenation.

  6. Longitudinal foliation rigidity and Lipschitz-continuous invariant forms for hyperbolic flows

    OpenAIRE

    Foulon, Patrick; Hasselblatt, Boris

    2010-01-01

    In several contexts the defining invariant structures of a hyperbolic dynamical system are smooth only in systems of algebraic origin (smooth rigidity), and we prove new results of this type for a class of flows. For a compact Riemannian manifold and a uniformly quasiconformal transversely symplectic Anosov flow we define the longitudinal KAM-cocycle and use it to prove a rigidity result: The joint stable/unstable subbundle is Zygmund-regular, and higher regularity implies vanishing of the lo...

  7. Flow induced formation of dual-phase continuity in polymer blends and alloys

    DEFF Research Database (Denmark)

    Lyngaae-Jørgensen, Jørgen; Chtcherbakova, E.A.; Utracki, L.A.

    1997-01-01

    showed that an addition of block copolymer may narrow the volume fraction range where bi-continuous phase structures are formed. Both annealing in the molten stale and shearing history influence the measured phi(cr) for formation of bi-continuous phase structure in amorphous immiscible polymer blends....

  8. MHD flow and heat transfer from continuous surface in uniform free stream of non-Newtonian fluid

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    An analysis is carried out to study the steady flow and heat transfer characteristics from a continuous flat surface moving in a parallel free stream of an electrically conducting non-Newtonian viscoelastic fluid. The flow is subjected to a transverse uniform magnetic field. The constitutive equation of the fluid is modeled by that for a second grade fluid. Numerical results are obtained for the distribution of velocity and temperature profiles. The effects of various physical parameters like viscoelastic parameter, magnetic parameter and Prandtl number on various momentum and heat transfer characteristics are discussed in detail and shown graphically.

  9. Extended continuous-flow stirred-tank reactor (ECSTR) as a simple model of life under thermodynamically open conditions

    Science.gov (United States)

    Takinoue, Masahiro; Ma, Yue; Mori, Yoshihito; Yoshikawa, Kenichi

    2009-07-01

    A continuous-flow stirred-tank reactor (CSTR) is a vital tool for investigating the nonlinear dynamics of chemical systems. This report proposes an extended CSTR (ECSTR) inspired by active and passive transports through a closed membrane in living systems. In addition to the externally-controlled flow in a conventional CSTR, we introduce passive diffusion through a membrane into the ECSTR. This extension allows us to control the chemical dynamics with a larger parameter-dimension. Numerical analyses show that the ECSTR can expand an oscillatory region in the parameter space and can convert a non-oscillatory chemical system to an oscillatory system.

  10. A polystyrene-supported 9-amino(9-deoxy)epi quinine derivative for continuous flow asymmetric Michael reactions.

    Science.gov (United States)

    Izquierdo, Javier; Ayats, Carles; Henseler, Andrea H; Pericàs, Miquel A

    2015-04-14

    A polystyrene (PS)-supported 9-amino(9-deoxy)epi quinine derivative catalyzes Michael reactions affording excellent levels of conversion and enantioselectivity using different nucleophiles and structurally diverse enones. The highly recyclable, immobilized catalyst has been used to implement a single-pass, continuous flow process (residence time: 40 min) that can be operated for 21 hours without significant decrease in conversion and with improved enantioselectivity with respect to batch operation. The flow process has also been used for the sequential preparation of a small library of enantioenriched Michael adducts.

  11. Capacity Expansion and Reliability Evaluation on the Networks Flows with Continuous Stochastic Functional Capacity

    Directory of Open Access Journals (Sweden)

    F. Hamzezadeh

    2014-01-01

    Full Text Available In many systems such as computer network, fuel distribution, and transportation system, it is necessary to change the capacity of some arcs in order to increase maximum flow value from source s to sink t, while the capacity change incurs minimum cost. In real-time networks, some factors cause loss of arc’s flow. For example, in some flow distribution systems, evaporation, erosion or sediment in pipes waste the flow. Here we define a real capacity, or the so-called functional capacity, which is the operational capacity of an arc. In other words, the functional capacity of an arc equals the possible maximum flow that may pass through the arc. Increasing the functional arcs capacities incurs some cost. There is a certain resource available to cover the costs. First, we construct a mathematical model to minimize the total cost of expanding the functional capacities to the required levels. Then, we consider the loss of flow on each arc as a stochastic variable and compute the system reliability.

  12. A continuous flow isotope ratio mass spectrometry method for high precision determination of dissolved gas ratios and isotopic composition

    DEFF Research Database (Denmark)

    Charoenpong, C. N.; Bristow, L. A.; Altabet, M. A.

    2014-01-01

    ratio mass spectrometer (IRMS). A continuous flow of He carrier gas completely degasses the sample, and passes through the preparation and purification system before entering the IRMS for analysis. The use of this continuous He carrier permits short analysis times (less than 8 min per sample......) as compared with current high-precision methods. In addition to reference gases, calibration is achieved using air-equilibrated water standards of known temperature and salinity. Assessment of reference gas injections, air equilibrated standards, as well as samples collected in the field shows the accuracy...

  13. Continuous flow PSA system carbon dioxide gas sep aration Process. Renzoku ryu PSA hoshiki tansan gas bunri process

    Energy Technology Data Exchange (ETDEWEB)

    Kanamaru, T.; Urano, S.; Kinoshita, N.; Ota, K. (Seibu Gas Kabushiki Kaisha, Fukuoka (Japan)); Nishino, K. (Mitsubishi Petrochemical Engineering Co. Ltd., Tokyo (Japan))

    1990-10-10

    During the production process of substitute natural gas (SNG), CO {sub 2} and moisture is removed which is contained in the wet mixed gas consisting of H {sub 2}, CH {sub 4} and CO {sub 2}, etc. generated in the gas generator. As the methods to separate and remove the CO {sub 2} above, there are the liquid absorption system as the wet decarbonation technique and the pressure swing adsorption (PSA) system as the dry decarbonation technique, but either of them has various problems. The process introduced in this article is the technique which has been developed in order to solve the various problems above and separates the contunuous wet mixed gas flow (generated gas before the treatment) consisting of H {sub 2}, CH {sub 4} and CO {sub 2}, etc. generated in the gas generator into the combustible component gas flow with purity of 99% or more and the CO {sub 2} gas flow with purity of 99%, both flows being the continuous flows without fluctuation of flow rate, pressure and component, and recovers 99% of the conbustible component and CO {sub 2} both. The above process was developed by Seibu Gas Co.. Starting, stopping and load change of the plant using this system is done quickly, accurately and easily with a high degree of safety, and the one touch operation is also possible. 6 figs., 3 tabs.

  14. Growth of Myxococcus xanthus in continuous-flow-cell bioreactors as a method for studying development.

    Science.gov (United States)

    Smaldone, Gregory T; Jin, Yujie; Whitfield, Damion L; Mu, Andrew Y; Wong, Edward C; Wuertz, Stefan; Singer, Mitchell

    2014-04-01

    Nutrient sensors and developmental timers are two classes of genes vital to the establishment of early development in the social soil bacterium Myxococcus xanthus. The products of these genes trigger and regulate the earliest events that drive the colony from a vegetative state to aggregates, which ultimately leads to the formation of fruiting bodies and the cellular differentiation of the individual cells. In order to more accurately identify the genes and pathways involved in the initiation of this multicellular developmental program in M. xanthus, we adapted a method of growing vegetative populations within a constant controllable environment by using flow cell bioreactors, or flow cells. By establishing an M. xanthus community within a flow cell, we are able to test developmental responses to changes in the environment with fewer concerns for effects due to nutrient depletion or bacterial waste production. This approach allows for greater sensitivity in investigating communal environmental responses, such as nutrient sensing. To demonstrate the versatility of our growth environment, we carried out time-lapse confocal laser scanning microscopy to visualize M. xanthus biofilm growth and fruiting body development, as well as fluorescence staining of exopolysaccharides deposited by biofilms. We also employed the flow cells in a nutrient titration to determine the minimum concentration required to sustain vegetative growth. Our data show that by using a flow cell, M. xanthus can be held in a vegetative growth state at low nutrient concentrations for long periods, and then, by slightly decreasing the nutrient concentration, cells can be allowed to initiate the developmental program.

  15. Startup and long term operation of enhanced biological phosphorus removal in continuous-flow reactor with granules.

    Science.gov (United States)

    Li, Dong; Lv, Yufeng; Zeng, Huiping; Zhang, Jie

    2016-07-01

    The startup and long term operation of enhanced biological phosphorus removal (EBPR) in a continuous-flow reactor (CFR) with granules were investigated in this study. Through reducing the settling time from 9min to 3min gradually, the startup of EBPR in a CFR with granules was successfully realized in 16days. Under continuous-flow operation, the granules with good phosphorus and COD removal performance were stably operated for more than 6months. And the granules were characterized with particle size of around 960μm, loose structure and good settling ability. During the startup phase, polysaccharides (PS) was secreted excessively by microorganisms to resist the influence from the variation of operational mode. Results of relative quantitative PCR indicated that granules dominated by polyphosphate-accumulating organisms (PAOs) were easier accumulated in the CFR because more excellent settling ability was needed in the system. PMID:27085149

  16. [Treatment of chronic pain of oncologic origin with epidural or intrathecal morphine administered by continuous or programmable flow implanted pumps].

    Science.gov (United States)

    Rodríguez López, M J; de la Torre Liébanas, M; Sánchez-Guijo Bernal, J J; Muñoz de la Guardia, J L

    1990-01-01

    We have treated a total of 40 patients who presented chronic pain secondary to a neoplastic condition; the patients were treated with morphine in a continuous perfusion by means of an implanted perfusion pump. The route used was the epidural route in seven patients and the intrathecal route in the remaining 33 patients. In 22 patients, the implanted pump was the continuous flow Infusaid model and in the remaining 18, the programmable flow Synchromed (Medtronic) model. The daily dose of morphine ranged from 2.4 mg to 48 mg and maximum perfusion period was 19 months. Main complications were displacement of the catheter and rejection of perfusion system. Despite its high prize, we believe that such treatment system should be considered because of the quality of life improvement of the patients. PMID:2098877

  17. Continuous-flow homogeneous catalysis using the temperature-controlled solvent properties of supercritical carbon dioxide.

    Science.gov (United States)

    Harwardt, Thomas; Franciò, Giancarlo; Leitner, Walter

    2010-09-28

    A fully integrated continuous process for homogeneous catalysed reactions in scCO(2) has been developed exploiting the tunable solvent properties of scCO(2). A heated condenser situated above the reaction zone leads to a phase split under isobaric conditions resulting in efficient catalyst retention and recirculation. Continuous isomerisation of allylic alcohols was carried out for over 200 hours time-on-stream demonstrating the viability of this approach.

  18. Continuous dependence for the Brinkman equations of flow in double-diffusive convection

    Directory of Open Access Journals (Sweden)

    Changhao Lin

    2007-06-01

    Full Text Available This paper concerns the structural stability for convective motion in a fluid-saturated porous medium under the Brinkman scheme. Continuous dependence for the solutions on the gravity coefficients and the Soret coefficient are proved. First of all, an a priori bound in $L^2$ norm is derived whereby we show the solution depends continuously in $L^2$ norm on changes in the gravity coefficients and the Soret coefficient. This estimate also implies that the solutions decay exponentially.

  19. Oxidative Stress, DNA Damage and Repair in Heart Failure Patients after Implantation of Continuous Flow Left Ventricular Assist Devices

    OpenAIRE

    Mondal, Nandan Kumar; Sorensen, Erik; Hiivala, Nicholas; Feller, Erika; Griffith, Bartley; Wu, Zhongjun Jon

    2013-01-01

    Objective: To study the status of oxidative stress and DNA damage repair in circulating blood leukocytes of heart failure patients supported by continuous flow left ventricular assist devices (LVADs). Materials and methods: Ten HF patients implanted with LVAD as bridge to transplant or destination therapy were enrolled in the study and 10 age and sex matched volunteers were recruited as the study control. Reactive oxygen species (ROS) in blood leukocytes and superoxide dismutase (SOD) in eryt...

  20. Tube-in-tube reactor as a useful tool for homo- and heterogeneous olefin metathesis under continuous flow mode.

    Science.gov (United States)

    Skowerski, Krzysztof; Czarnocki, Stefan J; Knapkiewicz, Paweł

    2014-02-01

    A tube-in-tube reactor was successfully applied in homo- and heterogeneous olefin metathesis reactions under continuous flow mode. It was shown that the efficient removal of ethylene facilitated by connection of the reactor with a vacuum pump significantly improves the outcome of metathesis reactions. The beneficial aspects of this approach are most apparent in reactions performed at low concentration, such as macrocyclization reactions. The established system allows achievement of both improved yield and selectivity, and is ideal for industrial applications.

  1. Continuous-Flow Synthesis of Deuterium-Labeled Antidiabetic Chalcones: Studies towards the Selective Deuteration of the Alkynone Core

    OpenAIRE

    Sándor B. Ötvös; Chi-Ting Hsieh; Yang-Chang Wu; Jih-Heng Li; Fang-Rong Chang; Ferenc Fülöp

    2016-01-01

    Flow chemistry-based syntheses of deuterium-labeled analogs of important antidiabetic chalcones were achieved via highly controlled partial C≡C bond deuteration of the corresponding 1,3-diphenylalkynones. The benefits of a scalable continuous process in combination with on-demand electrolytic D2 gas generation were exploited to suppress undesired over-reactions and to maximize reaction rates simultaneously. The novel deuterium-containing chalcone derivatives may have interesting biological ef...

  2. Continuous 'Passive' flow-proportional monitoring of drainage using a new modified Sutro weir (MSW) unit.

    Science.gov (United States)

    Vendelboe, Anders Lindblad; Rozemeijer, Joachim; de Jonge, Lis Wollesen; de Jonge, Hubert

    2016-03-01

    In view of their crucial role in water and solute transport, enhanced monitoring of agricultural subsurface drain tile systems is important for adequate water quality management. However, existing monitoring techniques for flow and contaminant loads from tile drains are expensive and labour intensive. The aim of this study was to develop a cost-effective and simple method for monitoring loads from tile drains. The Flowcap is a modified Sutro weir (MSW) unit that can be attached to the outlet of tile drains. It is capable of registering total flow, contaminant loads and flow-averaged concentrations. The MSW builds on a modern passive sampling technique that responds to hydraulic pressure and measures average concentrations over time (days to months) for various substances. Mounting the samplers in the MSW allowed a flow-proportional part of the drainage to be sampled. Laboratory testing yielded high linear correlation between the accumulated sampler flow, q total, and accumulated drainage flow, Q total (r (2) > 0.96). The slope of these correlations was used to calculate the total drainage discharge from the sampled volume, and therefore contaminant load. A calibration of the MSW under controlled laboratory condition was needed before interpretation of the monitoring results was possible. The MSW does not require a shed, electricity, or maintenance. This enables large-scale monitoring of contaminant loads via tile drains, which can improve contaminant transport models and yield valuable information for the selection and evaluation of mitigation options to improve water quality. Results from this type of monitoring can provide data for the evaluation and optimisation of best management practices in agriculture in order to produce the highest yield without water quality and recipient surface waters being compromised. PMID:26914326

  3. Unlocking the potential of supported liquid phase catalysts with supercritical fluids: low temperature continuous flow catalysis with integrated product separation

    Science.gov (United States)

    Franciò, Giancarlo; Hintermair, Ulrich; Leitner, Walter

    2015-01-01

    Solution-phase catalysis using molecular transition metal complexes is an extremely powerful tool for chemical synthesis and a key technology for sustainable manufacturing. However, as the reaction complexity and thermal sensitivity of the catalytic system increase, engineering challenges associated with product separation and catalyst recovery can override the value of the product. This persistent downstream issue often renders industrial exploitation of homogeneous catalysis uneconomical despite impressive batch performance of the catalyst. In this regard, continuous-flow systems that allow steady-state homogeneous turnover in a stationary liquid phase while at the same time effecting integrated product separation at mild process temperatures represent a particularly attractive scenario. While continuous-flow processing is a standard procedure for large volume manufacturing, capitalizing on its potential in the realm of the molecular complexity of organic synthesis is still an emerging area that requires innovative solutions. Here we highlight some recent developments which have succeeded in realizing such systems by the combination of near- and supercritical fluids with homogeneous catalysts in supported liquid phases. The cases discussed exemplify how all three levels of continuous-flow homogeneous catalysis (catalyst system, separation strategy, process scheme) must be matched to locate viable process conditions. PMID:26574523

  4. Unlocking the potential of supported liquid phase catalysts with supercritical fluids: low temperature continuous flow catalysis with integrated product separation.

    Science.gov (United States)

    Franciò, Giancarlo; Hintermair, Ulrich; Leitner, Walter

    2015-12-28

    Solution-phase catalysis using molecular transition metal complexes is an extremely powerful tool for chemical synthesis and a key technology for sustainable manufacturing. However, as the reaction complexity and thermal sensitivity of the catalytic system increase, engineering challenges associated with product separation and catalyst recovery can override the value of the product. This persistent downstream issue often renders industrial exploitation of homogeneous catalysis uneconomical despite impressive batch performance of the catalyst. In this regard, continuous-flow systems that allow steady-state homogeneous turnover in a stationary liquid phase while at the same time effecting integrated product separation at mild process temperatures represent a particularly attractive scenario. While continuous-flow processing is a standard procedure for large volume manufacturing, capitalizing on its potential in the realm of the molecular complexity of organic synthesis is still an emerging area that requires innovative solutions. Here we highlight some recent developments which have succeeded in realizing such systems by the combination of near- and supercritical fluids with homogeneous catalysts in supported liquid phases. The cases discussed exemplify how all three levels of continuous-flow homogeneous catalysis (catalyst system, separation strategy, process scheme) must be matched to locate viable process conditions.

  5. Gadolinium separation from HNO3 acidic streams of the nuclear fuel reprocessing by a new continuous flow extraction method

    International Nuclear Information System (INIS)

    A method for the continuous transfer of gadolinium from one aqueous phase into another was developed, based on the extraction from a light 0.5 M HNO3 phase into a heavier organic phase consisting of 63 Vol% HDEHP (Bis-(2-ethylhexyl)-hydrogen-phosphate) in CHCl3 and the subsequent stripping of the ion into a heavy 4 M H2SO4 solution. During operation the two aqueous phases are mobile, while the organic phase is the stationary one. It was shown that an equilibrium between extraction and stripping builds up that can be maintained for hours. The gadolinium separation achieved by this method allows not only the transfer of this ion into a pure aqueous medium with only a short delay between extraction and stripping, but also its continuous enrichment in the stripping phase. Thus, the apparatus is an ideal tool for combination with analytical flow methods that need purification steps prior to analysis, like continuous fluorimetric Gd determination in nitric acid streams. The best working conditions for the system were determined by examining the influences of the mobile phases flow rates, the ratios of flow rates between the two aqueous streams, and the stirring efficiency. (orig.)

  6. Unlocking the potential of supported liquid phase catalysts with supercritical fluids: low temperature continuous flow catalysis with integrated product separation.

    Science.gov (United States)

    Franciò, Giancarlo; Hintermair, Ulrich; Leitner, Walter

    2015-12-28

    Solution-phase catalysis using molecular transition metal complexes is an extremely powerful tool for chemical synthesis and a key technology for sustainable manufacturing. However, as the reaction complexity and thermal sensitivity of the catalytic system increase, engineering challenges associated with product separation and catalyst recovery can override the value of the product. This persistent downstream issue often renders industrial exploitation of homogeneous catalysis uneconomical despite impressive batch performance of the catalyst. In this regard, continuous-flow systems that allow steady-state homogeneous turnover in a stationary liquid phase while at the same time effecting integrated product separation at mild process temperatures represent a particularly attractive scenario. While continuous-flow processing is a standard procedure for large volume manufacturing, capitalizing on its potential in the realm of the molecular complexity of organic synthesis is still an emerging area that requires innovative solutions. Here we highlight some recent developments which have succeeded in realizing such systems by the combination of near- and supercritical fluids with homogeneous catalysts in supported liquid phases. The cases discussed exemplify how all three levels of continuous-flow homogeneous catalysis (catalyst system, separation strategy, process scheme) must be matched to locate viable process conditions. PMID:26574523

  7. SURFATM-NH3: a model combining the surface energy balance and bi-directional exchanges of ammonia applied at the field scale

    Directory of Open Access Journals (Sweden)

    E. Personne

    2009-08-01

    Full Text Available A new biophysical model SURFATM-NH3, simulating the ammonia (NH3 exchange between terrestrial ecosystems and the atmosphere is presented. SURFATM-NH3 consists of two coupled models: (i an energy budget model and (ii a pollutant exchange model, which distinguish the soil and plant exchange processes. The model describes the exchanges in terms of adsorption to leaf cuticles and bi-directional transport through leaf stomata and soil. The results of the model are compared with the flux measurements over grassland during the GRAMINAE Integrated Experiment at Braunschweig, Germany. The dataset of GRAMINAE allows the model to be tested in various meteorological and agronomic conditions: prior to cutting, after cutting and then after the application of mineral fertilizer. The whole comparison shows close agreement between model and measurements for energy budget and ammonia fluxes. The major controls on the ground and plant emission potential are the physicochemical parameters for liquid-gas exchanges which are integrated in the compensation points for live leaves, litter and the soil surface. Modelled fluxes are highly sensitive to soil and plant surface temperatures, highlighting the importance of accurate estimates of these terms. The model suggests that the net flux depends not only on the foliar (stomatal compensation point but also that of leaf litter. SURFATM-NH3 represents a comprehensive approach to studying pollutant exchanges and its link with plant and soil functioning. It also provides a simplified generalised approach (SVAT model applicable for atmospheric transport models.

  8. Development a bi-directional sampler with invention patent for geotechnical experiments%土工实验双向制样仪研制

    Institute of Scientific and Technical Information of China (English)

    蔡明星; 聂良佐; 侯天顺

    2013-01-01

    A bi-directional sampler with invention patent for geotechnical experiments is introduced ,which is easy to overcome the one-way vertical multilayer compaction by shackles ,to eliminate density heterogeneity of the sample structures ,to improve problems of data uncertainties ,discreteness and poor curve fitting of the experimental samples .It is good for controlling uniform density of sample structures ,optimizing the states and tests of the experimental samples to achieve the goal of geotechnical experimental teaching and research services .%推介一种获得发明专利的土工实验双向制样仪,便于克服单向垂直多层击实方式束缚,消除了样品结构密度不均一,克服了样品实验数据的不可确定性、离散性及实验曲线拟合性差问题,为控制样品结构密度均一、优化实验样品状态及测试、实现土工实验教学与研究目标服务。

  9. Quantitative measurements of one-dimensional OH absolute concentration profiles in a methane/air flat flame by bi-directional laser-induced fluorescence

    Institute of Scientific and Technical Information of China (English)

    于欣; 杨振; 彭江波; 张蕾; 马欲飞; 杨超博; 李晓晖; 孙锐

    2015-01-01

    The one-dimensional (1D) spatial distributions of OH absolute concentration in methane/air laminar premixed flat flame under different equivalence ratios at atmospheric pressure are investigated by using bi-directional laser-induced flu-orescence (LIF) detection scheme combined with the direct absorption spectroscopy. The effective peak absorption cross section and the average temperature at a height of 2 mm above the burner are obtained by exciting absorption on the Q1(8) rotational line in the A2Σ+ (υ0=0)←X2Π(υ0 =0) at 309.240 nm. The measured values are 1.86×10−15 cm2 and 1719 K, respectively. Spatial filtering and frequency filtering methods of reducing noise are used to deal with the experi-mental data, and the smoothing effects are also compared using the two methods. The spatial distribution regularities of OH concentration are obtained with the equivalence ratios ranging from 0.8 to 1.3. The spatial resolution of the measured result is 84 µm. Finally, a comparison is made between the experimental result of this paper and other relevant study results.

  10. Priming in the Type I-F CRISPR-Cas system triggers strand-independent spacer acquisition, bi-directionally from the primed protospacer.

    Science.gov (United States)

    Richter, Corinna; Dy, Ron L; McKenzie, Rebecca E; Watson, Bridget N J; Taylor, Corinda; Chang, James T; McNeil, Matthew B; Staals, Raymond H J; Fineran, Peter C

    2014-07-01

    Clustered regularly interspaced short palindromic repeats (CRISPR), in combination with CRISPR associated (cas) genes, constitute CRISPR-Cas bacterial adaptive immune systems. To generate immunity, these systems acquire short sequences of nucleic acids from foreign invaders and incorporate these into their CRISPR arrays as spacers. This adaptation process is the least characterized step in CRISPR-Cas immunity. Here, we used Pectobacterium atrosepticum to investigate adaptation in Type I-F CRISPR-Cas systems. Pre-existing spacers that matched plasmids stimulated hyperactive primed acquisition and resulted in the incorporation of up to nine new spacers across all three native CRISPR arrays. Endogenous expression of the cas genes was sufficient, yet required, for priming. The new spacers inhibited conjugation and transformation, and interference was enhanced with increasing numbers of new spacers. We analyzed ∼ 350 new spacers acquired in priming events and identified a 5'-protospacer-GG-3' protospacer adjacent motif. In contrast to priming in Type I-E systems, new spacers matched either plasmid strand and a biased distribution, including clustering near the primed protospacer, suggested a bi-directional translocation model for the Cas1:Cas2-3 adaptation machinery. Taken together these results indicate priming adaptation occurs in different CRISPR-Cas systems, that it can be highly active in wild-type strains and that the underlying mechanisms vary.

  11. Application of Heterogeneous Copper Catalyst in a Continuous Flow Process: Dehydrogenation of Cyclohexanol

    Science.gov (United States)

    Glin´ski, Marek; Ulkowska, Urszula; Iwanek, Ewa

    2016-01-01

    In this laboratory experiment, the synthesis of a supported solid catalyst (Cu/SiO2) and its application in the dehydrogenation of cyclohexanol performed under flow conditions was studied. The experiment was planned for a group of two or three students for two 6 h long sessions. The copper catalyst was synthesized using incipient wetness…

  12. A continuous flow microfluidic calorimeter: 3-D numerical modeling with aqueous reactants

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Mehmet A., E-mail: mehmet.sen@mathworks.com [Northeastern University, Department of Mechanical and Industrial Engineering, 360 Hungtington Avenue, 334 Snell Engineering Center, Boston, MA 02115 (United States); Kowalski, Gregory J., E-mail: gkowal@coe.neu.edu [Northeastern University, Department of Mechanical and Industrial Engineering, 360 Hungtington Avenue, 334 Snell Engineering Center, Boston, MA 02115 (United States); Fiering, Jason, E-mail: jfiering@draper.com [Charles Stark Draper Laboratory, 555 Technology Square, Cambridge, MA 02139 (United States); Larson, Dale, E-mail: dlarson@draper.com [Charles Stark Draper Laboratory, 555 Technology Square, Cambridge, MA 02139 (United States)

    2015-03-10

    Highlights: • A co-flow microreactor is modeled in flow, reaction/diffusion, and thermal domains. • Analysis shows how arrayed temperature sensors can provide enthalpy of reaction. • Optical plasmonic temperature sensors could be arrayed suitably for calorimetry. • The reactor studied has a volume of 25 nL. - Abstract: A computational analysis of the reacting flow field, species diffusion and heat transfer processes with thermal boundary layer effects in a microchannel reactor with a coflow configuration was performed. Two parallel adjacent streams of aqueous reactants flow along a wide, shallow, enclosed channel in contact with a substrate, which is affixed to a temperature controlled plate. The Fluent computational fluid dynamics package solved the Navier–Stokes, mass transport and energy equations. The energy model, including the enthalpy of reaction as a nonuniform heat source, was validated by calculating the energy balance at several control volumes in the microchannel. Analysis reveals that the temperature is nearly uniform across the channel thickness, in the direction normal to the substrate surface; hence, measurements made by sensors at or near the surface are representative of the average temperature. Additionally, modeling the channel with a glass substrate and a silicone cover shows that heat transfer is predominantly due to the glass substrate. Finally, using the numerical results, we suggest that a microcalorimeter could be based on this configuration, and that temperature sensors such as optical nanohole array sensors could have sufficient spatial resolution to determine enthalpy of reaction.

  13. Boundary Layer Flow over a Continuously Moving Thin Needle in a Parallel Free Stream

    Institute of Scientific and Technical Information of China (English)

    Anuar Ishak; Roslinda Nazar; Ioan Pop

    2007-01-01

    We investigate the boundary-layer flow on a moving isothermal thin needle parallel to a moving stream. The governing equations are solved numerically by a finite-difference method. Dual solutions are found to exist when the needle and the free stream move in the opposite directions.

  14. A Pressure Controlled Pinched Flow Fractionation Device for Continuous Particle Separation

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lehrmann; Trosborg, Jacqueline; Tanzi, Simone;

    2012-01-01

    In this work the problem of separating small particles of di↵erent sizes is solved by developing a simple microfluidic device using pinched flow fractionation (PFF), a technique originally presented by Yamada et al. in 2004 [1]. The present work takes the concept of PFF to the next level by makin...

  15. Combined Microfluidic-Eectric Diffused Mixing of Living Cells in Continuous Flow

    Science.gov (United States)

    Wang, Ming-Wen

    2010-02-01

    The mixing process is a crucially important stage in the operation of biological and chemical microfluidic devices. If the mixing is inadequate, reactants do not fully interact with each other, and the device may not operate properly. This paper describes a simplified microfluidic mixer (different from a chaotic mixer) which can uniformly mix a buffer solution with living cells by applying an AC electric charge. Diffusion of the living cells into the buffer solution occurs rapidly following the interface of the flow stream with the electric charge; no further agitating step is needed. To accomplish this, an asymmetric pair of electrodes was integrated at the inlets of the buffer solution and the cells fluid. When the buffer solution and the cells fluid were introduced into one flow path, they remained limited to that flow stream. When the electrodes were charged, however, the cells in a short distance were efficiently moved into the solution flow, and the original fluids were mixed. The mixing efficiency depends on the polarizability of the cells, and this in turn is governed by the dielectric properties of the cells, the medium, and the solvent. This micro device, capable of efficiently mixing living cells with a buffer solution, may potentially allow biological mixing to be done outside of hospitals, in facilities without biological analyzing instruments.

  16. 耐高压双向椭圆齿轮微小流量计研究%High-pressure Bi-directional Oval Gear Tiny-flow Meter

    Institute of Scientific and Technical Information of China (English)

    丁凡; 邓民胜; 刘硕; 丁川; 满在朋; 李其朋

    2015-01-01

    提出了一种基于低偏心率椭圆齿轮转子适用于高压下微小流量计量的双向椭圆齿轮流量计结构,阐述了该种流量计的工作原理,给出了低偏心率椭圆齿轮转子的节曲线及齿廓方程,并设计了样机进行实验研究.实验表明,在31.5 MPa以下,0.05~3 L/min流量范围内的计量精度可达±0.5%,在0.03 ~3 L/min流量范围内的计量精度可达±1%,具有耐高压、结构简单、精度高、脉动小、可双向计量等优点.

  17. Continuous formation of N-chloro-N,N-dialkylamine solutions in well-mixed meso-scale flow reactors

    Science.gov (United States)

    Jolley, Katherine E

    2015-01-01

    Summary The continuous flow synthesis of a range of organic solutions of N,N-dialkyl-N-chloramines is described using either a bespoke meso-scale tubular reactor with static mixers or a continuous stirred tank reactor. Both reactors promote the efficient mixing of a biphasic solution of N,N-dialkylamine in organic solvent, and aqueous sodium hypochlorite to achieve near quantitative conversions, in 72–100% in situ yields, and useful productivities of around 0.05 mol/h with residence times from 3 to 20 minutes. Initial calorimetric studies have been carried out to inform on reaction exotherms, rates and safe operation. Amines which partition mainly in the organic phase require longer reaction times, provided by the CSTR, to compensate for low mass transfer rates in the biphasic system. The green metrics of the reaction have been assessed and compared to existing procedures and have shown the continuous process is improved over previous procedures. The organic solutions of N,N-dialkyl-N-chloramines produced continuously will enable their use in tandem flow reactions with a range of nucleophilic substrates. PMID:26734089

  18. Continuous formation of N-chloro-N,N-dialkylamine solutions in well-mixed meso-scale flow reactors

    Directory of Open Access Journals (Sweden)

    A. John Blacker

    2015-12-01

    Full Text Available The continuous flow synthesis of a range of organic solutions of N,N-dialkyl-N-chloramines is described using either a bespoke meso-scale tubular reactor with static mixers or a continuous stirred tank reactor. Both reactors promote the efficient mixing of a biphasic solution of N,N-dialkylamine in organic solvent, and aqueous sodium hypochlorite to achieve near quantitative conversions, in 72–100% in situ yields, and useful productivities of around 0.05 mol/h with residence times from 3 to 20 minutes. Initial calorimetric studies have been carried out to inform on reaction exotherms, rates and safe operation. Amines which partition mainly in the organic phase require longer reaction times, provided by the CSTR, to compensate for low mass transfer rates in the biphasic system. The green metrics of the reaction have been assessed and compared to existing procedures and have shown the continuous process is improved over previous procedures. The organic solutions of N,N-dialkyl-N-chloramines produced continuously will enable their use in tandem flow reactions with a range of nucleophilic substrates.

  19. Continuous formation of N-chloro-N,N-dialkylamine solutions in well-mixed meso-scale flow reactors.

    Science.gov (United States)

    Blacker, A John; Jolley, Katherine E

    2015-01-01

    The continuous flow synthesis of a range of organic solutions of N,N-dialkyl-N-chloramines is described using either a bespoke meso-scale tubular reactor with static mixers or a continuous stirred tank reactor. Both reactors promote the efficient mixing of a biphasic solution of N,N-dialkylamine in organic solvent, and aqueous sodium hypochlorite to achieve near quantitative conversions, in 72-100% in situ yields, and useful productivities of around 0.05 mol/h with residence times from 3 to 20 minutes. Initial calorimetric studies have been carried out to inform on reaction exotherms, rates and safe operation. Amines which partition mainly in the organic phase require longer reaction times, provided by the CSTR, to compensate for low mass transfer rates in the biphasic system. The green metrics of the reaction have been assessed and compared to existing procedures and have shown the continuous process is improved over previous procedures. The organic solutions of N,N-dialkyl-N-chloramines produced continuously will enable their use in tandem flow reactions with a range of nucleophilic substrates.

  20. Isolation of plasma from whole blood using a microfludic chip in a continuous cross-flow

    Institute of Scientific and Technical Information of China (English)

    CHEN Xing; CUI DaFu; ZHANG LuLu

    2009-01-01

    A novel microfluidic chip is developed for crossflow filtration plasma from the whole blood which is carried out in a continuous manner. This microfluidic chip was made of a silicon substrate sealed with a compound cover. The silicon substrate fabricated by micro-electro-mechanical system (MEMS)technology consisted of microposts array, microchannels and reservoirs. Then the silicon substrate was characterized by Scaning Electron Microscopy (SEM). The performance of the microfiuidic chip was valued by the experiments of plasma isolation. During more than one hour of continuous blood infusion through the chip, there were no problems of jamming or clogging, and the plasma selectivity of 97.78% was achieved. Due to the chip's simple structure and control mechanism with a continuous,real time operating manner, this microfluidic chip is easily expected to be integrated into micro total analytical system (uTAS) which will create a microanalysis system for point-of-care diagnostics.

  1. Residence times and mixing of a novel continuous oscillatory flow meso reactor

    OpenAIRE

    Reis, N.; A.A. Vicente; Teixeira, J. A.; Mackley, M.R.

    2004-01-01

    A novel meso reactor based on oscillatory flow technology (Harvey et al., 2001) has been recently presented in Harvey et al. (2003) as a new technology for reaction engineering and particle suspension applications. Due to the demonstrated enhanced performances for fluid micro mixing and suspension of catalyst beads and to the small volume of the reactor, this novel miniature reactor is suitable for applications at specialist chemical manufacture and high throughput screening. F...

  2. Gold film-catalysed benzannulation by Microwave-Assisted, Continuous Flow Organic Synthesis (MACOS

    Directory of Open Access Journals (Sweden)

    Gjergji Shore

    2009-07-01

    Full Text Available Methodology has been developed for laying down a thin gold-on-silver film on the inner surface of glass capillaries for the purpose of catalysing benzannulation reactions. The cycloaddition precursors are flowed through these capillaries while the metal film is being heated to high temperatures using microwave irradiation. The transformation can be optimized rapidly, tolerates a wide number of functional groups, is highly regioselective, and proceeds in good to excellent conversion.

  3. A High-Resolution Continuous Flow Analysis System for Polar Ice Cores

    DEFF Research Database (Denmark)

    Dallmayr, Remi; Goto-Azuma, Kumiko; Kjær, Helle Astrid;

    2016-01-01

    signals of abrupt climate change in deep polar ice cores. To test its performance, we used the system to analyze different climate intervals in ice drilled at the NEEM (North Greenland Eemian Ice Drilling) site, Greenland. The quality of our continuous measurement of stable water isotopes has been...... at NEEM camp....

  4. Chemical Homogenization Of Liquid Steel Flowed Through Continuous Casting Slab Tundish During Alloying Process

    Directory of Open Access Journals (Sweden)

    Cwudziński A.

    2015-06-01

    Full Text Available This paper presents the results of research on the behaviour of an alloy addition in steel flowing through the tundish used for casting slabs. The device under examination is a wedge-shaped single-nozzle tundish of a capacity of 30 Mg. Due to the complexity of alloy addition dissolution and dispersion in metallurgical processes, a decision was made to use the Species Model available within the Ansys-Fluent® program. For describing the turbulence, the Realizable k-ɛ model was chosen. By defining the heat losses on respective planes making up the virtual model, the non-isothermal conditions existing during the flow of liquid steel through the tundish were considered. From the performed numerical simulations, the fields of steel flow and steel temperature and alloy addition concentration in the tundish working space were obtained. In order to accurately illustrate the process of chemical homogenization in the tundish working space, mixing curves were recorded. Based on the obtained results (mixing curves, the mixing time needed for achieving the 95% level of chemical homogenization was calculated.

  5. Analysis and Design of Two-stage Isolated Bi-directional DC/DC Converter%一种两级式隔离型双向DC/DC变换器的分析与设计

    Institute of Scientific and Technical Information of China (English)

    张东; 王一军

    2016-01-01

    A two-stage isolated bi-directional DC/DC converter is proposed. The converter is composed of a regulated front-end DC/DC converter and a unregulated back-end LLC resonant converter. When the energy flows from low-voltage DC bus to high-voltage DC bus, the converter is equivalent to Boost converter cascaded full bridge LLC resonant converter with output voltage doubling. When the energy flow is reversed, the converter is equivalent to half bridge LLC resonant converter cascaded Buck converter. The operational theory and key design point are analyzed, and efficiency-oriented optimization method of middle-voltage DC bus is proposed. A prototype of 1kW, 12 V/336 V is build, and the optimum nominal voltage of middle-voltage DC bus is 50 V. The experimental results verify the good performance of the proposed converter.%提出了一种两级式隔离型双向DC/DC变换器,该变换器包含一个闭环的前级DC/DC变换器和一个开环的后级LLC谐振变换器。当能量从低压直流母线传输到高压直流母线时,变换器等效为Boost变换器+全桥倍压LLC谐振变换器;当能量反方向流动时,变换器等效为半桥LLC谐振变换器+Buck变换器。通过分析变换器工作原理与设计要点,提出了以效率为目标的中间直流母线电压优化方法,并研制了1台12 V/336 V、1 kW的样机,其优化后的中间直流母线电压额定值为50 V。样机实验结果验证了所提变换器的良好工作性能。

  6. EVALUATION OF THE USEFULNESS OF CONTINUOUS FLOW ANALYSIS FOR THE STUDY OF ANIONIC SURFACTANTS AND NONIONIC SURFACTANTS IN WATER AND SEWAGE SAMPLES

    OpenAIRE

    Aleksandra Strugała-Wilczek; Małgorzata Bebek; Agnieszka Rodak

    2014-01-01

    In this paper, continuous flow analyzer has been examined for the usefulness for the determination of anionic surfactants and nonionics in real water and sewage samples. The study used a segmented flow analyzer (SFA) SAN++ (Skalar, Netherlands) with photometric detection. Environmental water and sewage samples of different origin and standard solutions were under test. By appropriate selection of analytical conditions in continuous flow system, it has been possible to obtain satisfactory valu...

  7. Segregation behavior of magnetic ions in continuous flowing solution under gradient magnetic field

    Institute of Scientific and Technical Information of China (English)

    Bing Ji; Ping Wu; Han Ren; Shiping Zhang; Abdul Rehman; Li Wang

    2016-01-01

    The research of magnetic separation starts from magnetic solid particles to nanoparticles, and in the research progress, particles become smaller gradually with the development of application of magnetic separation technology. Nevertheless, little experimental study of magnetic separation of molecules and ions under continuous fl owing conditions has been re-ported. In this work, we designed a magnetic device and a“layered”fl ow channel to study the magnetic separation at the ionic level in continuous fl owing solution. A segregation model was built to discuss the segregation behavior as well as the factors that may affect the separation. The magnetic force was proved to be the driving force which plays an indispensable role leading to the segregation and separation. The fl ow velocity has an effect on the segregation behavior of magnetic ions, which determines the separation result. On the other hand, the optimum fl ow velocity which makes maximum separation is related to the initial concentration of solution.

  8. Explicit construction of an autonomous Hamiltonian system exhibiting continual directed flow

    International Nuclear Information System (INIS)

    We construct a prototypical example of a spatially-open autonomous Hamiltonian system in which localised, but otherwise unbiased, ensembles of initial conditions break spatio-temporal symmetries in the subsequent ensemble dynamics, despite time reversal symmetry of the equations of motion. Together with transient chaos, this provides the mechanism for the occurrence of a current. Transporting trajectories pass through transient chaos and subsequently cross surfaces of no-return, after which they perform solely regular motion so that the current is of continual ballistic nature. -- Highlights: ► An autonomous Hamiltonian system of 2 integrable subsystems coupled locally. ► Trajectories escape potential wells, via transient chaos, to transporting motion. ► Localised initial conditions break symmetries, leading to a current. ► Surfaces of no return are constructed demonstrating that transport is continual.

  9. Continuous Flow Separation of Hydrophobin Fusion Proteins from Plant Cell Culture Extract.

    Science.gov (United States)

    Reuter, Lauri J; Conley, Andrew J; Joensuu, Jussi J

    2016-01-01

    Fusion to fungal hydrophobins has proven to be a useful tool to enhance accumulation and recovery of recombinant proteins in plants. Aqueous two-phase separation (ATPS) is an attractive system to capture hydrophobin fusion proteins from plant extracts. The process can simultaneously purify and concentrate target protein with minimal background. ATPS avoids the use of chromatographic column steps, can be carried out in a short time frame, and is amenable to industrial-scale protein purification. A drawback of performing ATPS in large volumes is the lengthy time required for phase separation; however, this can be avoided by incorporating continuous systems, which are often preferred by the processing industry. This method chapter illustrates the capture of GFP-HFBI hydrophobin fusion protein from BY-2 plant cell suspension extract using a semi-continuous ATPS method. PMID:26614291

  10. Performance evaluation of a continuous flow photocatalytic reactor for wastewater treatment.

    Science.gov (United States)

    Rezaei, Mohammad; Rashidi, Fariborz; Royaee, Sayed Javid; Jafarikojour, Morteza

    2014-11-01

    A novel photocatalytic reactor for wastewater treatment was designed and constructed. The main part of the reactor was an aluminum tube in which 12 stainless steel circular baffles and four quartz tube were placed inside of the reactor like shell and tube heat exchangers. Four UV-C lamps were housed within the space of the quartz tubes. Surface of the baffles was coated with TiO2. A simple method was employed for TiO2 immobilization, while the characterization of the supported photocatalyst was based on the results obtained through performing some common analytical methods such as X-ray diffraction (XRD), scanning electron microscope (SEM), and BET. Phenol was selected as a model pollutant. A solution of a known initial concentration (20, 60, and 100 ppmv) was introduced to the reactor. The reactor also has a recycle flow to make turbulent flow inside of the reactor. The selected recycle flow rate was 7 × 10(-5) m(3).s(-1), while the flow rate of feed was 2.53 × 10(-7), 7.56 × 10(-7), and 1.26 × 10(-6) m(3).s(-1), respectively. To evaluate performance of the reactor, response surface methodology was employed. A four-factor three-level Box-Behnken design was developed to evaluate the reactor performance for degradation of phenol. Effects of phenol inlet concentration (20-100 ppmv), pH (3-9), liquid flow rate (2.53 × 10(-7)-1.26 × 10(-6) m(3).s(-1)), and TiO2 loading (8.8-17.6 g.m(-2)) were analyzed with this method. The adjusted R (2) value (0.9936) was in close agreement with that of corresponding R (2) value (0.9961). The maximum predicted degradation of phenol was 75.50 % at the optimum processing conditions (initial phenol concentration of 20 ppmv, pH ∼ 6.41, and flow rate of 2.53 × 10(-7) m(3).s(-1) and catalyst loading of 17.6 g.m(-2)). Experimental degradation of phenol determined at the optimum conditions was 73.7 %. XRD patterns and SEM images at the optimum conditions revealed that crystal size is approximately 25

  11. Mass flow prediction of the coriolis meter using C0 continuous beam elements

    Science.gov (United States)

    Binulal, B. R.; Rajan, Akash; Abhilash, Suryan R.; Kochupillai, Jayaraj; Kim, Heuy Dong

    2015-06-01

    A three node C0 continuous isoparametric beam element is formulated to model the curved pipe conveying fluid in three dimensional configuration. The equations of motion for the combined structure and fluid domain including added mass effect, Coriolis effect, centrifugal effect and the effect of pressure on the walls of pipe have been developed by Paidoussis. This equation is converted to finite element formulation using Galerkin technique and is validated with the results available from literature.

  12. TREATMENT OF TEXTILE WASTEWATER USING A CONTINUOUS FLOW ACTIVATED SLUDGE SYSTEM AT PILOT-SCALE

    OpenAIRE

    M. A. ABOULHASSAN; S. SOUABI; H. EL OUARGHI; M. A. BAHLAOUI

    2014-01-01

    Textile industry wastewaters contain high concentrations of organic matter, toxic substances and dyes and pigments, and are harmful to receiving environment. Activated sludge system at pilot scale with continuous feeding, was used for the treatment of a dyeing unit effluent. The results showed that treatment allows a removal rate of 40-56 % of chemical oxygen demand (COD), and 13 to 30 % of color. The adsorption on sludge appears to be the main process responsible for the color removal of was...

  13. Bromine-catalyzed conversion of CO2 and epoxides to cyclic carbonates under continuous flow conditions.

    Science.gov (United States)

    Kozak, Jennifer A; Wu, Jie; Su, Xiao; Simeon, Fritz; Hatton, T Alan; Jamison, Timothy F

    2013-12-11

    A continuous method for the formation of cyclic carbonates from epoxides and carbon dioxide (CO2) is described. The catalysts used are inexpensive and effective in converting the reagents to the products in a residence time (t(R)) of 30 min. The cyclic carbonate products are obtained in good to excellent yield (51-92%). On the basis of a series of kinetics experiments, we propose a reaction mechanism involving epoxide activation by electrophilic bromine and CO2 activation by an amide.

  14. Electrochemical study of multi-electrode microbial fuel cells under fed-batch and continuous flow conditions

    KAUST Repository

    Ren, Lijiao

    2014-07-01

    Power production of four hydraulically connected microbial fuel cells (MFCs) was compared with the reactors operated using individual electrical circuits (individual), and when four anodes were wired together and connected to four cathodes all wired together (combined), in fed-batch or continuous flow conditions. Power production under these different conditions could not be made based on a single resistance, but instead required polarization tests to assess individual performance relative to the combined MFCs. Based on the power curves, power produced by the combined MFCs (2.12 ± 0.03 mW, 200 ω) was the same as the summed power (2.13 mW, 50 ω) produced by the four individual reactors in fed-batch mode. With continuous flow through the four MFCs, the maximum power (0.59 ± 0.01 mW) produced by the combined MFCs was slightly lower than the summed maximum power of the four individual reactors (0.68 ± 0.02 mW). There was a small parasitic current flow from adjacent anodes and cathodes, but overall performance was relatively unaffected. These findings demonstrate that optimal power production by reactors hydraulically and electrically connected can be predicted from performance by individual reactors. © 2013 Elsevier B.V. All rights reserved.

  15. Continuous-flow Heck synthesis of 4-methoxybiphenyl and methyl 4-methoxycinnamate in supercritical carbon dioxide expanded solvent solutions

    Directory of Open Access Journals (Sweden)

    Phei Li Lau

    2013-12-01

    Full Text Available The palladium metal catalysed Heck reaction of 4-iodoanisole with styrene or methyl acrylate has been studied in a continuous plug flow reactor (PFR using supercritical carbon dioxide (scCO2 as the solvent, with THF and methanol as modifiers. The catalyst was 2% palladium on silica and the base was diisopropylethylamine due to its solubility in the reaction solvent. No phosphine co-catalysts were used so the work-up procedure was simplified and the green credentials of the reaction were enhanced. The reactions were studied as a function of temperature, pressure and flow rate and in the case of the reaction with styrene compared against a standard, stirred autoclave reaction. Conversion was determined and, in the case of the reaction with styrene, the isomeric product distribution was monitored by GC. In the case of the reaction with methyl acrylate the reactor was scaled from a 1.0 mm to 3.9 mm internal diameter and the conversion and turnover frequency determined. The results show that the Heck reaction can be effectively performed in scCO2 under continuous flow conditions with a palladium metal, phosphine-free catalyst, but care must be taken when selecting the reaction temperature in order to ensure the appropriate isomer distribution is achieved. Higher reaction temperatures were found to enhance formation of the branched terminal alkene isomer as opposed to the linear trans-isomer.

  16. The efficiency of turn-over processes in degraded peat as investigated under continuous flow conditions

    Science.gov (United States)

    Kleimeier, Christian; Karsten, Ulf; Janssen, Manon; Lennartz, Bernd

    2013-04-01

    Nitrate removal from run-off from agricultural land is in general required to reach a "good chemical status" of surface and groundwater bodies according to the European Water Framework Directive. Removing nitrates via heterotrophic denitrification is highly effective but requires stable anoxic environmental conditions as well as available organic carbon as an electron donator. Constructed wetlands, established on peat soils, through which the nitrate-loaded water is routed, may provide denitrification favorable conditions. A long-term flow experiment (mesocosm) was conducted employing a laboratory container set-up filled with decomposed peat aiming at quantifying the nitrate removal efficiency at various nitrate influx rates. The redox potential was measured at different depths to determine the spatial distribution of denitrificating zones. This new methodological approach allows the observation of biological nitrate turn over without interrupting the adjusted flow rate. We investigated the hydraulic properties and derived transport parameters for the mesocosm by analyzing experimental data from tracer tests. The obtained bromide breakthrough curves (BTC) were subjected to model analysis using the CXTFIT routine of the STANMOD software package. It could be demonstrated that the degraded peat has a dual porosity structure with roughly 40% of the pore water not participating in convective flow and transport processes. Further, the first flushing of mineralized nitrate upon rewetting and onset of flux may compromise any positive clean-up and nitrate removal effects occurring during long-term operation of peat wetlands. The development of the spatial sequence of bacterial cultures is characterized by the redox potential. It is dominated by the available substrates that serve as electron acceptors in bacterial respiration and occurs in a thermodynamically determined top-down order. The zonal development of the nitrate-consuming bacteria was observed and used to describe

  17. Dissipation of hydrological tracers and the herbicide S-metolachlor in batch and continuous-flow wetlands.

    Science.gov (United States)

    Maillard, Elodie; Lange, Jens; Schreiber, Steffi; Dollinger, Jeanne; Herbstritt, Barbara; Millet, Maurice; Imfeld, Gwenaël

    2016-02-01

    Pesticide dissipation in wetland systems with regard to hydrological conditions and operational modes is poorly known. Here, we investigated in artificial wetlands the impact of batch versus continuous-flow modes on the dissipation of the chiral herbicide S-metolachlor (S-MET) and hydrological tracers (bromide, uranine and sulforhodamine B). The wetlands received water contaminated with the commercial formulation Mercantor Gold(®) (960 g L(-1) of S-MET, 87% of the S-enantiomer). The tracer mass budget revealed that plant uptake, sorption, photo- and presumably biodegradation were prominent under batch mode (i.e. characterized by alternating oxic-anoxic conditions), in agreement with large dissipation of S-MET (90%) under batch mode. Degradation was the main dissipation pathway of S-MET in the wetlands. The degradate metolachlor oxanilic acid (MOXA) mainly formed under batch mode, whereas metolachlor ethanesulfonic acid (MESA) prevailed under continuous-flow mode, suggesting distinct degradation pathways in each wetland. R-enantiomer was preferentially degraded under batch mode, which indicated enantioselective biodegradation. The release of MESA and MOXA by the wetlands as well as the potential persistence of S-MET compared to R-MET under both oxic and anoxic conditions may be relevant for groundwater and ecotoxicological risk assessment. This study shows the effect of batch versus continuous modes on pollutant dissipation in wetlands, and that alternate biogeochemical conditions under batch mode enhance S-MET biodegradation.

  18. A chemiluminescence-based continuous flow aqueous ozone analyzer using photoactivated chromotropic acid.

    Science.gov (United States)

    Takayanagi, Toshio; Dasgupta, Purnendu K

    2005-05-15

    Ozone has become the oxidant of choice for water disinfection, especially in large water treatment facilities. This paper describes a fast and sensitive method for the determination of ozone content by reaction with photoactivated chromotropic acid (CA, 4,5-dihydroxynaphthalene-2,7-disulfonic acid), which results in intense chemiluminescence (CL). Freshly ozonated water from a recirculating ozonizer/reservoir is injected into a carrier stream of deionized water in the flow-injection mode. This flow mixes with a stream of photoactivated CA solution in a spiral cell placed directly on top of an inexpensive miniature (8mm diameter active area) photomultiplier tube (PMT). Alkaline CA is photoactivated by passing it through a FEP-Teflon((R)) coil (residence time approximately 50s) wrapped around a 1W UV lamp emitting at 254nm; without photoactivation, the signal is approximately 70-fold lower. The S/N=3 limit of detection for aqueous ozone is 3mugl(-1) and good response slope is obtained up to an ozone concentration of 1.4mgl(-1), the highest that could be made in this study. The response obeyed a quadratic equation with r(2)=0.9984. No interference from permanganate ion is observed. The proposed system was applied to the monitoring of ozonation status of a playa lake water that exhibited significant ozone demand.

  19. Continuous Polyol Synthesis of Metal and Metal Oxide Nanoparticles Using a Segmented Flow Tubular Reactor (SFTR

    Directory of Open Access Journals (Sweden)

    Andrea Testino

    2015-06-01

    Full Text Available Over the last years a new type of tubular plug flow reactor, the segmented flow tubular reactor (SFTR, has proven its versatility and robustness through the water-based synthesis of precipitates as varied as CaCO3, BaTiO3, Mn(1−xNixC2O4·2H2O, YBa oxalates, copper oxalate, ZnS, ZnO, iron oxides, and TiO2 produced with a high powder quality (phase composition, particle size, and shape and high reproducibility. The SFTR has been developed to overcome the classical problems of powder production scale-up from batch processes, which are mainly linked with mass and heat transfer. Recently, the SFTR concept has been further developed and applied for the synthesis of metals, metal oxides, and salts in form of nano- or micro-particles in organic solvents. This has been done by increasing the working temperature and modifying the particle carrying solvent. In this paper we summarize the experimental results for four materials prepared according to the polyol synthesis route combined with the SFTR. CeO2, Ni, Ag, and Ca3(PO42 nanoparticles (NPs can be obtained with a production rate of about 1–10 g per h. The production was carried out for several hours with constant product quality. These findings further corroborate the reliability and versatility of the SFTR for high throughput powder production.

  20. Continuous Flow Controlled Synthesis of Gold Nanoparticles Using Pulsed Mixing Microfluidic System

    Directory of Open Access Journals (Sweden)

    Guojun Liu

    2015-01-01

    Full Text Available To prepare the gold nanoparticles (AuNPs with uniform sizes, fine morphology, and good monodispersity, a pulsed mixing microfluidic system based on PZT actuation was presented. The system includes PZT micropump and Y type micromixer. By adjusting voltage (entrance flow rate, pulsed frequency, phase, and other parameters, a variety of mixing modes can be achieved, so as to realize the controllable synthesis of nanoparticles in a certain range. By numerical simulation and analysis, the channel section size, entrance angle, and pulse frequency were optimized. Based on the optimized structure and working parameters, the test prototype has been manufactured in lab, and the related synthesis tests of AuNPs were carried out. The test results indicate that AuNPs with uniform morphology and good monodispersity can be synthesized using the system with the section size (0.4 mm × 0.4 mm, the entrance channel angle (60° under condition of the pulsed frequency (300 Hz, and the entrance flow rate (4 mL/min. The average diameter and its standard deviation of AuNPs synthesized were 21.6 nm, 4.83 nm, respectively. The research work above can be applied to the fields such as the controlled synthesis of noble metal nanoparticles, biomedicine, and microchemical system.

  1. Continuous Flow Deformability-Based Separation of Circulating Tumor Cells Using Microfluidic Ratchets.

    Science.gov (United States)

    Park, Emily S; Jin, Chao; Guo, Quan; Ang, Richard R; Duffy, Simon P; Matthews, Kerryn; Azad, Arun; Abdi, Hamidreza; Todenhöfer, Tilman; Bazov, Jenny; Chi, Kim N; Black, Peter C; Ma, Hongshen

    2016-04-13

    Circulating tumor cells (CTCs) offer tremendous potential for the detection and characterization of cancer. A key challenge for their isolation and subsequent analysis is the extreme rarity of these cells in circulation. Here, a novel label-free method is described to enrich viable CTCs directly from whole blood based on their distinct deformability relative to hematological cells. This mechanism leverages the deformation of single cells through tapered micrometer scale constrictions using oscillatory flow in order to generate a ratcheting effect that produces distinct flow paths for CTCs, leukocytes, and erythrocytes. A label-free separation of circulating tumor cells from whole blood is demonstrated, where target cells can be separated from background cells based on deformability despite their nearly identical size. In doping experiments, this microfluidic device is able to capture >90% of cancer cells from unprocessed whole blood to achieve 10(4) -fold enrichment of target cells relative to leukocytes. In patients with metastatic castration-resistant prostate cancer, where CTCs are not significantly larger than leukocytes, CTCs can be captured based on deformability at 25× greater yield than with the conventional CellSearch system. Finally, the CTCs separated using this approach are collected in suspension and are available for downstream molecular characterization. PMID:26917414

  2. Suction prevention and physiologic control of continuous flow left ventricular assist devices using intrinsic pump parameters.

    Science.gov (United States)

    Wang, Yu; Koenig, Steven C; Slaughter, Mark S; Giridharan, Guruprasad A

    2015-01-01

    The risk for left ventricular (LV) suction during left ventricular assist devices (LVAD) support has been a clinical concern. Current development efforts suggest LVAD suction prevention and physiologic control algorithms may require chronic implantation of pressure or flow sensors, which can be unreliable because of baseline drift and short lifespan. To overcome this limitation, we designed a sensorless suction prevention and physiologic control (eSPPC) algorithm that only requires LVAD intrinsic parameters (pump speed and power). Two gain-scheduled, proportional-integral controllers maintain a differential pump speed (ΔRPM) above a user-defined threshold to prevent LV suction while maintaining an average reference differential pressure (ΔP) between the LV and aorta. ΔRPM is calculated from noisy pump speed measurements that are low-pass filtered, and ΔP is estimated using an extended Kalman filter. Efficacy and robustness of the eSPPC algorithm were evaluated in silico during simulated rest and exercise test conditions for 1) excessive ΔP setpoint (ES); 2) rapid eightfold increase in pulmonary vascular resistance (PVR); and 3) ES and PVR. Simulated hemodynamic waveforms (LV pressure and volume; aortic pressure and flow) using only intrinsic pump parameters showed the feasibility of our proposed eSPPC algorithm in preventing LV suction for all test conditions. PMID:25396276

  3. Numerical Simulation of the Fluid Flow, Heat Transfer, and Solidification in a Twin-Roll Strip Continuous Casting Machine

    Science.gov (United States)

    Xu, Mianguang; Zhu, Miaoyong; Wang, Guodong

    2015-03-01

    In this paper, a three-dimensional enthalpy-porosity mixture solidification model is employed to describe the basic rules of heat transfer and solidification in a twin-roll strip continuous casting machine equipped with a multi-port trough-shaped feeding system, and reasons for the formation of these rules are analyzed. The two-layer zonal turbulence model is used to incorporate the turbulence in fluid flow, and the fluid flow in the wedge-shaped pool region in various conditions is studied. The results show that the fluid flow field in the pool region is quite different with/without the consideration of rotating rolls when the solidification is ignored, which indicates the importance of the consideration of rotating rolls in the water modeling equipment design. There are three aspects including molten steel jet impingement, roll rotating, and backward flow of the mushy zone, which strongly influence the temperature distribution in the pool region. The solidification process in the pool region could be divided into three stages: at the first stage, there exists a fast solidification region which obeys the square root law, and an approximately linear growth region could be found at the second stage, while a parabolic growth region could be found at the last stage. The formation of the first stage and the last stage could be mainly due to the geometry of the feeding system and the backward flow of the mushy zone, respectively. The first stage of solidification could be modified by a better designed feeding system, but the backward flow of mushy zone determined by the properties of metals and casting parameters could be one of the biggest obstacles for commercial production of steel sheets by a twin-roll caster.

  4. Continuous flow simulation in the Bârlad river basin, Romania

    Science.gov (United States)

    Corbuş, Ciprian; Mic, Rodica Paula; Mătreaţă, Marius

    2014-05-01

    This paper presents the partial results obtained into the project CLIMHYDEX ("Changes in Climate Extremes and associated impact on hydrological events in Romania") project that, among others, have as objectives the development of hydrological models at different spatial and temporal scales and the impact of climate change on extreme runoff in Bârlad catchment. To estimate the impact of climate change and variability on the flow regime in Bârlad catchment CONSUL hydrological model, with lumped parameters, was used. This rainfall-runoff deterministic model simulates the most significant hydrological processes within a hydrographic basin: snow-melting, interception, retention in the depressions, evapotranspiration, infiltration, surface runoff, hypodermic runoff, percolation, base runoff. According to the schematic representation (physiographic modelling) of how water flows and collects in a river basin the model computes the discharge hydrographs on selected simulation points on the river network and then performs their routing and composition on the main river and tributaries. After physiographic modelling resulted for Bârlad river basin: 56 sub-basins and 30 river reaches. CONSUL model was calibrated using historical data in Bârlad river basin by simulating the flow during 1975-2010. Calculation of average precipitation and air temperature (hydrological model input data) for each sub-basin was performed using a pre-processing program of meteorological data from original rectangular grid nodes corresponding to Bârlad river basin, averaging being achieved as weighted values based on the representativeness of these nodes for each analyzed sub-basin. In order to estimate the initial values of CONSUL model parameters the generalization relationships of these parameters based on morphometric characteristics of the river basin or river reach were used. Calibration of model parameters was performed in two stages: (i) individual and (ii) globally. (i) Individual

  5. Quantifying the Reactive Uptake of OH by Organic Aerosols in aContinuous Flow Stirred Tank Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Che, Dung L.; Smith, Jared D.; Leone, Stephen R.; Ahmed, Musahid; Wilson, Kevin R.

    2009-03-01

    Here we report a new method for measuring the heterogeneous chemistry of submicron organic aerosol particles using a continuous flow stirred tank reactor. This approach is designed to quantify the real time heterogeneous kinetics, using a relative rate method, under conditions of low oxidant concentration and long reaction times that more closely mimic the real atmosphere. A general analytical expression, which couples the aerosol chemistry with the flow dynamics in the chamber is developed and applied to the heterogeneous oxidation of squalane particles by hydroxyl radicals (OH) in the presence of O2. The particle phase reaction is monitored via photoionization aerosol mass spectrometry and yields a reactive uptake coefficient of 0.51+-0.10, using OH concentrations of 1-7x108 molec cdot cm-3 and reaction times of 1.5+-3 hours. This uptake coefficient is larger than that found for the reaction carried out under high OH concentrations (~;;1x1010 molec cdot cm-3) and short reaction times in a flow tube reactor. This difference suggests that oxidant concentration and reaction time are not interchangeable quantities in reactions of organic aerosols with radicals. In general, this approach provides a new way to examine how the chemical aging of organic particles measured at short reaction times and high oxidant concentrations in flow tubes might differ from the long reaction times and low oxidant levels found in the real atmosphere.

  6. Single-pass continuous-flow leach test of PNL 76-68 glass: some selected Bead Leach I results

    International Nuclear Information System (INIS)

    A single-pass continuous-flow leach test of PNL 76-68 glass beads (7 mm dia) was concluded after 420 days of uninterrupted operation. Variables included in the experimental matrix were flow-rate, leachant composition, and temperature. Analysis was conducted on all leachate samples for 237Np and 239Pu as well as a number of nonradioactive elements. Results indicated that flow-rate and leachant systematically affected the leach rate, but only slightly. Temperature effects were significant. Plutonium leach rate was lower at higher temperature suggesting that Pu sorption onto the beads was enhanced at the higher temperature. The range of leach rates for all analyzed elements (except Pu), at both temperatures, at all three flow rates, and with all three leachant compositions varied over only three orders of magnitude. The range of variables used in this experiment covered those expected in many proposed repository environments. The preliminary interpretation of the results aPPh3 also reacted with Mn2(CO)10 and Cp2Mo2(CO)6 to give a variety of products at room temperature. A radical mechanism was suggested

  7. High velocity continuous-flow reactor for the production of solar grade silicon

    Science.gov (United States)

    Woerner, L.

    1977-01-01

    The feasibility of a high volume, high velocity continuous reduction reactor as an economical means of producing solar grade silicon was tested. Bromosilanes and hydrogen were used as the feedstocks for the reactor along with preheated silicon particles which function both as nucleation and deposition sites. A complete reactor system was designed and fabricated. Initial preheating studies have shown the stability of tetrabromosilane to being heated as well as the ability to preheat hydrogen to the desired temperature range. Several test runs were made and some silicon was obtained from runs carried out at temperatures in excess of 1180 K.

  8. In-Water and Neat Batch and Continuous-Flow Direct Esterification and Transesterification by a Porous Polymeric Acid Catalyst

    Science.gov (United States)

    Baek, Heeyoel; Minakawa, Maki; Yamada, Yoichi M. A.; Han, Jin Wook; Uozumi, Yasuhiro

    2016-05-01

    A porous phenolsulphonic acid—formaldehyde resin (PAFR) was developed. The heterogeneous catalyst PAFR was applied to the esterification of carboxylic acids and alcohols, affording the carboxylic acid esters in a yield of up to 95% where water was not removed from the reaction mixture. Surprisingly, the esterification in water as a solvent proceeded to afford the desired esters in high yield. PAFR provided the corresponding esters in higher yield than other homogeneous and heterogeneous catalysts. The transesterification of alcohols and esters was also investigated by using PAFR, giving the corresponding esters. PAFR was applied to the batch-wise and continuous-flow production of biodiesel fuel FAME. The PAFR-packed flow reactor that was developed for the synthesis of carboxylic acids and FAME worked for four days without loss of its catalytic activity.

  9. Geological Factors Affecting Flow Spatial Continuity in Water Injection of Units Operating in the LGITJ–0102 Ore Body

    Directory of Open Access Journals (Sweden)

    Ilver M. Soto-Loaiza

    2016-05-01

    Full Text Available The objective of the investigation was to identify the geological factors affecting the spatial continuity of the flow during the process of flank water injection in the units operating in the Lower Lagunilla Hydrocarbon Ore Body. This included the evaluation of the recovery factor, the petro-physic properties such as porosity, permeability, water saturation and rock type and quality in each flow unit. it was observed that the rock type of the geologic structure in the ore body is variable. The lowest values for the petro-physic properties were found in the southern area while a high variability of these parameters was observed in the northern and central areas. It was concluded that the northern area has a great potential for the development of new injection projects for petroleum recovery.

  10. Ndt80 activates the meiotic ORC1 transcript isoform and SMA2 via a bi-directional middle sporulation element in Saccharomyces cerevisiae.

    Science.gov (United States)

    Xie, Bingning; Horecka, Joe; Chu, Angela; Davis, Ronald W; Becker, Emmanuelle; Primig, Michael

    2016-09-01

    The origin of replication complex subunit ORC1 is important for DNA replication. The gene is known to encode a meiotic transcript isoform (mORC1) with an extended 5'-untranslated region (5'-UTR), which was predicted to inhibit protein translation. However, the regulatory mechanism that controls the mORC1 transcript isoform is unknown and no molecular biological evidence for a role of mORC1 in negatively regulating Orc1 protein during gametogenesis is available. By interpreting RNA profiling data obtained with growing and sporulating diploid cells, mitotic haploid cells, and a starving diploid control strain, we determined that mORC1 is a middle meiotic transcript isoform. Regulatory motif predictions and genetic experiments reveal that the activator Ndt80 and its middle sporulation element (MSE) target motif are required for the full induction of mORC1 and the divergently transcribed meiotic SMA2 locus. Furthermore, we find that the MSE-binding negative regulator Sum1 represses both mORC1 and SMA2 during mitotic growth. Finally, we demonstrate that an MSE deletion strain, which cannot induce mORC1, contains abnormally high Orc1 levels during post-meiotic stages of gametogenesis. Our results reveal the regulatory mechanism that controls mORC1, highlighting a novel developmental stage-specific role for the MSE element in bi-directional mORC1/SMA2 gene activation, and correlating mORC1 induction with declining Orc1 protein levels. Because eukaryotic genes frequently encode multiple transcripts possessing 5'-UTRs of variable length, our results are likely relevant for gene expression during development and disease in higher eukaryotes. PMID:27362276

  11. Bi-directional induction of matrix metalloproteinase-9 and tissue inhibitor of matrix metalloproteinase-1 during T lymphoma/endothelial cell contact: implication of ICAM-1.

    Science.gov (United States)

    Aoudjit, F; Potworowski, E F; St-Pierre, Y

    1998-03-15

    The mechanisms that lead to the expression of matrix metalloproteinases (MMP) and tissue inhibitors of MMP (TIMPs) during the invasive process of normal and transformed T cells remain largely unknown. Since vascular cells form a dynamic tissue capable of responding to local stimuli and activating cells through the expression of cytokine receptors and specific cell adhesion molecules, we hypothesized that the firm adhesion of T lymphoma cells to endothelial cells is a critical event in the local production of MMP and TIMP. In the present work, we show that adhesion of lymphoma cells to endothelial cells induced a transient and reciprocal de novo expression of MMP-9 mRNA and enzymatic activity by both cell types. Up-regulation of MMP-9 in T lymphoma cells was concomitant to that of TIMP-1, and required direct contact with endothelial cells. Induction of MMP-9, but not of TIMP-1, was blocked by anti-LFA-1 and anti-intercellular adhesion molecule-1 Abs, indicating that induction of MMP-9 and TIMP-1 in lymphoma cells required direct, yet distinct, intercellular contact. In contrast, the induction of MMP-9 in endothelial cells by T lymphoma cells did not necessitate direct contact and could be achieved by exposure to IL-1 and TNF, or to the supernatant of T lymphoma cell culture. Together, these results demonstrate that firm adhesion of T lymphoma cells to endothelial cells participates in the production of MMP-9 in both cell types through bi-directional signaling pathways, and identify intercellular adhesion molecule-1/LFA-1 as a key interaction in the up-regulation of MMP-9 in T lymphoma cells.

  12. Salt weathering in Egyptian limestone after laboratory simulations with continuous flow of salt solutions at different temperatures

    Science.gov (United States)

    Aly, Nevin; Gomez-Heras, Miguel; Hamed, Ayman; Alvarez de Buergo, Monica

    2013-04-01

    weathering in Egyptian limestone after laboratory simulations with continuous flow of salt solutions at different temperatures Nevin Aly Mohamed (1), Miguel Gomez - Heras(2), Ayman Hamed Ahmed (1), and Monica Alvarez de Buergo(2). (1) Faculty of Pet. & Min. Engineering- Suez Canal University, Suez, Egypt, (2) Instituto de Geociencias (CSIC-UCM) Madrid. Spain. Limestone is one of the most frequent building stones in Egypt and is used since the time of ancient Egyptians and salt weathering is one of the main threats to its conservation. Most of the limestone used in historical monuments in Cairo is a biomicrite extracted from the Mid-Eocene Mokattam Group. During this work, cylindrical samples (2.4 cm diameter and approx. 4.8 cm length) were subjected, in a purpose-made simulation chamber, to simulated laboratory weathering tests with fixed salt concentration (10% weight NaCl solution), at different temperatures, which were kept constant throughout each test (10, 20, 30, 40 oC). During each test, salt solutions flowed continuously imbibing samples by capilarity. Humidity within the simulation chamber was reduced using silica gel to keep it low and constant to increase evaporation rate. Temperature, humidity inside the simulation chamber and samples weight were digitally monitored during each test. Results show the advantages of the proposed experimental methodology using a continuous flow of salt solutions and shed light on the effect of temperature on the dynamics of salt crystallization on and within samples. Research funded by mission sector of high education ministry, Egypt and Geomateriales S2009/MAT-1629.

  13. Epileptic Seizure Detection and Prediction Based on Continuous Cerebral Blood Flow Monitoring – a Review

    Directory of Open Access Journals (Sweden)

    Senay Tewolde

    2015-01-01

    Full Text Available Epilepsy is the third most common neurological illness, affecting 1% of the world’s population. Despite advances in medicine, about 25 to 30% of the patients do not respond to or cannot tolerate the severe side effects of medical treatment, and surgery is not an option for the majority of patients with epilepsy. The objective of this article is to review the current state of research on seizure detection based on cerebral blood flow (CBF data acquired by thermal diffusion flowmetry (TDF, and CBF-based seizure prediction. A discussion is provided on the applications, advantages, and disadvantages of TDF in detecting and localizing seizure foci, as well as its role in seizure prediction. Also presented are an overview of the present challenges and possible future research directions (along with methodological guidelines of the CBF-based seizure detection and prediction methods.

  14. Reagent-free determination of amikacin content in amikacin sulfate injections by FTIR derivative spectroscopy in a continuous flow system

    Directory of Open Access Journals (Sweden)

    José F. Ovalles

    2014-04-01

    Full Text Available The quantitative estimation of amikacin (AMK in AMK sulfate injection samples is reported using FTIR-derivative spectrometric method in a continuous flow system. Fourier transform of mid-IR spectra were recorded without any sample pretreatment. A good linear calibration (r>0.999, %RSD<2.0 in the range of 7.7–77.0 mg/mL was found. The results showed a good correlation with the manufacturer's and overall they all fell within acceptable limits of most pharmacopoeial monographs on AMK sulfate.

  15. Continuous Separation of Inclusions from Aluminum Melt Flowing in a Circular Pipe using a High Frequency Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The continuous separation of inclusions from aluminum melt flowing in a circular pipe using a high frequency magneticfield was investigated both theoretically and experimentally. The separation efficiency was calculated based on thetrajectory method and compared with experimental results. lt is found that the separation efficiency is a function ofnondimensional parameters ti @ d2B2/μfμea2 and a /δ The effective way to improve the separation efficiency is to increasethe effective magnetic flux density and decrease the pipe radius, and the value of a/δ should be kept about 2 in orderto obtain the optimum separation efficiency.

  16. Instrumentation of High Temperature and Pressure Reaction System with Continuous Flow and Its Hyphenation to a Liquid Chromatograph

    OpenAIRE

    Tsuda, Takao; Kitagawa, Shinya; Umeyama, Takayuki; Araki, Shuki; Hirashita, Tsunehisa; Aoki, Mutsumi; Nakamura, Koichi; キタガワ, シンヤ; アラキ, シュウキ; ヒラシタ, ツネヒサ; アオキ, ムツミ; 北川, 慎也; 荒木, 修喜; 平下, 恒久; 青木, 睦

    2006-01-01

    A continuous flow-type hydrothermal reaction system, in which both temperature and pressure were rapidly and dynamically controlled, was constructed. It is called a real time high temperature and pressure reaction system (RT-HighTP). The RT-HighTP was hyphenated with liquid chromatograph (RT-HighTP-LC) to achieve prompt analysis of the reaction products. The RT-HighTP system produced stable pressure under the supercritical and subcritical phases (%RSD < 3%). The RT-HighTP-LC was able to chang...

  17. Simultaneous measurement of X-ray small angle scattering, absorption and reactivity: A continuous flow catalysis reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sungsik; Lee, Byeongdu; Seifert, Soenke [X-ray Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Vajda, Stefan [Materials Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Center for Nanoscale Materials, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Department of Chemical Engineering, Yale University, 9 Hillhouse Avenue, New Haven, CT 06520 (United States); Winans, Randall E., E-mail: rewinans@anl.gov [X-ray Science Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

    2011-09-01

    A fixed-bed, continuous flow catalysis reactor is described, in which GISAXS (grazing incidence small angle X-ray scattering)/GIXAS (grazing incidence X-ray absorption spectroscopy) and TPR (temperature-programmed reaction) can be measured simultaneously on samples with low metal coverage. The capabilities offered by this setup are illustrated in the example of the dehydrogenation of cyclohexene, where the size, oxidation state and reactivity of supported cobalt clusters were investigated under ambient pressure conditions. The GIXAS data reveal an evolution of the oxidation state of the catalytic particles with temperature. Simultaneously recorded GISAXS data show stable clusters, without any indication of sintering under employed reaction conditions.

  18. Tube-in-tube reactor as a useful tool for homo- and heterogeneous olefin metathesis under continuous flow mode.

    Science.gov (United States)

    Skowerski, Krzysztof; Czarnocki, Stefan J; Knapkiewicz, Paweł

    2014-02-01

    A tube-in-tube reactor was successfully applied in homo- and heterogeneous olefin metathesis reactions under continuous flow mode. It was shown that the efficient removal of ethylene facilitated by connection of the reactor with a vacuum pump significantly improves the outcome of metathesis reactions. The beneficial aspects of this approach are most apparent in reactions performed at low concentration, such as macrocyclization reactions. The established system allows achievement of both improved yield and selectivity, and is ideal for industrial applications. PMID:24167003

  19. Continuous-Flow Synthesis of Deuterium-Labeled Antidiabetic Chalcones: Studies towards the Selective Deuteration of the Alkynone Core.

    Science.gov (United States)

    Ötvös, Sándor B; Hsieh, Chi-Ting; Wu, Yang-Chang; Li, Jih-Heng; Chang, Fang-Rong; Fülöp, Ferenc

    2016-01-01

    Flow chemistry-based syntheses of deuterium-labeled analogs of important antidiabetic chalcones were achieved via highly controlled partial C≡C bond deuteration of the corresponding 1,3-diphenylalkynones. The benefits of a scalable continuous process in combination with on-demand electrolytic D2 gas generation were exploited to suppress undesired over-reactions and to maximize reaction rates simultaneously. The novel deuterium-containing chalcone derivatives may have interesting biological effects and improved metabolic properties as compared with the parent compounds. PMID:26959006

  20. Continuous-Flow Synthesis of Deuterium-Labeled Antidiabetic Chalcones: Studies towards the Selective Deuteration of the Alkynone Core

    Directory of Open Access Journals (Sweden)

    Sándor B. Ötvös

    2016-03-01

    Full Text Available Flow chemistry-based syntheses of deuterium-labeled analogs of important antidiabetic chalcones were achieved via highly controlled partial C≡C bond deuteration of the corresponding 1,3-diphenylalkynones. The benefits of a scalable continuous process in combination with on-demand electrolytic D2 gas generation were exploited to suppress undesired over-reactions and to maximize reaction rates simultaneously. The novel deuterium-containing chalcone derivatives may have interesting biological effects and improved metabolic properties as compared with the parent compounds.