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Sample records for gas-liquid cylindrical cyclone

  1. DESIGN AND DEVELOPMENT OF GAS-LIQUID CYLINDRICAL CYCLONE COMPACT SEPARATORS FOR THREE-PHASE FLOW

    SciTech Connect

    Dr. Ram S. Mohan; Dr. Ovadia Shoham

    2003-06-25

    The U.S. Department of Energy (DOE) has awarded a five-year (1997-2002) grant (Mohan and Shoham, DE-FG26-97BC15024, 1997) to The University of Tulsa, to develop compact multiphase separation components for 3-phase flow. The research activities of this project have been conducted through cost sharing by the member companies of the Tulsa University Separation Technology Projects (TUSTP) research consortium and the Oklahoma Center for the Advancement of Science and Technology (OCAST). As part of this project, several individual compact separation components have been developed for onshore and offshore applications. These include gas-liquid cylindrical cyclones (GLCC{copyright}), liquid-liquid cylindrical cyclones (LLCC{copyright}), and the gas-liquid-liquid cylindrical cyclones (GLLCC{copyright}). A detailed study has also been completed for the liquid-liquid hydrocyclones (LLHC). Appropriate control strategies have been developed for proper operation of the GLCC{copyright} and LLCC{copyright}. Testing of GLCC{copyright} at high pressure and real crude conditions for field applications is also completed. Limited studies have been conducted on flow conditioning devices to be used upstream of the compact separators for performance improvement. This report presents a brief overview of the activities and tasks accomplished during the 5-year project period, October 1, 1997-March 31, 2003 (including the no-cost extended period of 6 months). An executive summary is presented initially followed by the tasks of the 5-year budget periods. Then, detailed description of the experimental and modeling investigations are presented. Subsequently, the technical and scientific results of the activities of this project period are presented with some discussions. The findings of this investigation are summarized in the ''Conclusions'' section, followed by relevant references. The publications resulting from this study in the form of MS Theses, Ph.D. Dissertation, Journal Papers and

  2. Design and Development of Gas-Liquid Cylindrical Cyclone Compact Separators for Three-Phase Flow

    SciTech Connect

    Mohan, Ram S.; Shoham, Ovadia

    1999-10-28

    The objective of this five-year project (October, 1997--September, 2002) is to expand the current research activities of Tulsa University Separation Technology Projects (TUSTP) to multiphase oil/water/gas separation. This project will be executed in two phases. Phase I (1997--2000) will focus on the investigations of the complex multiphase hydrodynamic flow behavior in a three-phase Gas-Liquid Cylindrical Cyclone (GLCC) Separator. The activities of this phase will include the development of a mechanistic model, a computational fluid dynamics (CFD) simulator, and detailed experimentation on the three-phase GLCC. The experimental and CFD simulation results will be suitably integrated with the mechanistic model. In Phase II (2000--2002), the developed GLCC separator will be tested under high pressure and real crudes conditions. This is crucial for validating the GLCC design for field application and facilitating easy and rapid technology deployment. Design criteria for industrial applications will be developed based on these results and will be incorporated into the mechanistic model by TUSTP.

  3. Design and Development of Gas-Liquid Cylindrical Cyclone Compact Separators for Three-Phase Flow

    SciTech Connect

    Mohan, R.S.; Shoham, O.

    2001-01-18

    The objective of this five-year project (October 1997 - September 2002) was to expand the current research activities of Tulsa University Separation Technology Projects (TUSTP) to multiphase oil/water/gas separation. This project was executed in two phases. Phase I (1997 - 2000) focused on the investigations of the complex multiphase hydrodynamic flow behavior in a three-phase Gas-Liquid Cylindrical Cyclone (GLCC) Separator. The activities of this phase included the development of a mechanistic model, a computational fluid dynamics (CFD) simulator, and detailed experimentation on the three-phase GLCC. The experimental and CFD simulation results will be suitably integrated with the mechanistic model. In Phase II (2000 - 2002), the developed GLCC separator will be tested under high pressure and real crude conditions. This is crucial for validating the GLCC design for field application and facilitating easy and rapid technology deployment. Design criteria for industrial applications will be developed based on these results and will be incorporated into the mechanistic model by TUSTP.

  4. Design and Development of Gas-Liquid Cylindrical Cyclone Compact Separators for Three-Phase Flow

    SciTech Connect

    Mohan, R.S.; Shoham, O.

    2001-01-10

    The objective of this five-year project (October 1997--September 2002) was to expand the current research activities of Tulsa University Separation Technology Projects (TUSTP) to multiphase oil/water/gas separation. This project was executed in two phases. Phase I (1997--2000) focused on the investigations of the complex multiphase hydrodynamic flow behavior in a three-phase Gas-Liquid Cylindrical Cyclone (GLCC) Separator. The activities of this phase included the development of a mechanistic model, a computational fluid dynamics (CFD) simulator, and detailed experimentation on the three-phase GLCC. The experimental and CFD simulation results will be suitably integrated with the mechanistic model. In Phase II (2000--2002), the developed GLCC separator will be tested under high pressure and real crude conditions. This is crucial for validating the GLCC design for field application and facilitating easy and rapid technology deployment. Design criteria for industrial applications will be developed based on these results and will be incorporated into the mechanistic model by TUSTP.

  5. DESIGN AND DEVELOPMENT OF GAS-LIQUID CYLINDRICAL CYCLONE COMPACT SEPARATORS FOR THREE-PHASE FLOW

    SciTech Connect

    Dr. Ram S. Mohan; Dr. Ovadia Shoham

    2000-04-28

    The objective of this five-year project (October, 1997-September, 2002) is to expand the current research activities of Tulsa University Separation Technology Projects (TUSTP) to multiphase oil/water/gas separation. This project will be executed in two phases. Phase I (1997-2000) will focus on the investigations of the complex multiphase hydrodynamic flow behavior in a three-phase Gas-Liquid Cylindrical Cyclone (GLCC{copyright}) Separator. The activities of this phase will include the development of a mechanistic model, a computational fluid dynamics (CFD) simulator, and detailed experimentation on the three-phase GLCC{copyright}. The experimental and CFD simulation results will be suitably integrated with the mechanistic model. In Phase II (2000-2002), the developed GLCC{copyright} separator will be tested under high pressure and real crudes conditions. This is crucial for validating the GLCC{copyright} design for field application and facilitating easy and rapid technology deployment. Design criteria for industrial applications will be developed based on these results and will be incorporated into the mechanistic model by TUSTP. This report presents a brief overview of the activities and tasks accomplished during the first half year (October 1, 1999-March 31, 2000) of the budget period (October 1, 1999-September 30, 2000). The total tasks of the budget period are given initially, followed by the technical and scientific results achieved till date. The report concludes with a detailed description of the plans for the conduct of the project for the second half year (April 1, 2000-September 30, 2000) of the current budget period.

  6. The effect of geometry and operation conditions on the performance of a gas-liquid cylindrical cyclone separator with new structure

    NASA Astrophysics Data System (ADS)

    Han, Qing; Zhang, Chi; Xu, Bo; Chen, Jiangping

    2013-07-01

    The hydrodynamic flow behavior, effects of geometry and working conditions of a gas-liquid cylindrical cyclone separator with a new structure are investigated by computational fluid dynamic and experiment. Gas liquid cylindrical cyclone separator is widely used in oil industry, refrigeration system because of its simple structure, high separating efficiency, little maintenance and no moving parts nor internal devices. In this work, a gas liquid cylindrical cyclone separator with new structure used before evaporator in refrigeration system can remove the vapor from the mixture and make evaporator compact by improving its heat exchange efficiency with the lower inlet quality. It also decreases evaporator pressure drop and reduces compressor work. The two pipes are placed symmetrically which makes each of them can be treated as inlet. It means when the fluids flow reverse, the separator performance will not be influence. Four samples with different geometry parameters are tested by experiment with different inlet quality (0.18-0.33), inlet mass flow rate (65-100kg/h). Compared with the experimental data, CFD simulation results show a good agreement. Eulerian multiphase model and Reynolds Stress Turbulence model are applied in the CFD simulation and obtained the inner flow field such as phase path lines, tangential velocity profiles and pressure and volume of fraction distribution contours. The separator body diameter (24, 36, 48mm) and inlet diameter (3.84, 4.8, 5.76mm) decide the maximum tangential velocity which results in the centrifugal force. The tangential velocity profiles are simulated and compared among different models. The higher tangential velocity makes higher quality of gas outlet but high pressure drop at the same time. Decreasing the inlet diameter increases quality of gas outlet pipe and pressure drop. High gas outlet quality is cost at high pressure drop. Increasing of separator diameter makes gas outlet quality increase first and then decrease but

  7. Integral cylindrical cyclone and loopseal assembly for CFB combustors

    SciTech Connect

    Alliston, M.G.; Wu, S.; Sinn, B.T.; Lato, K.

    1995-12-31

    The cyclone solids separator has been one of the main features characteristically associated with many Circulating Fluidized Bed combustor designs. Most designs incorporating the cyclone coflector also include a pressure sealing device through which the solids collected by the cyclone are returned to the combustor. The cyclone and the loopseal have typically been two separate components, and various designs have arisen for each component comprising refractory, water-cooled, or steam cooled equipment. The two obvious advantages of the use of water-cooled or steam-, cooled equipment are the reduction of refractory requirements and the conversion of these components into boiler-useful devices. The creation of these devices from tube and header assemblies has followed more-or-less artful paths, the directions of which have generally been based upon the goal of maintaining the specific geometric forms that had previously been used for CFB cyclones and loopseals. The assembly described in this paper was instead developed based upon the goals of (a) ease of manufacturing, (b) elimination of problematic components, (c) maximizing the boiler-usefulness of the surfaces created, and (d) adding potential process benefits. The resulting embodiment of these goals was a cylindrical vessel in which the upper portion forms the solids separator and the lower section is divided into chambers to form the loopseal. This report describes the details of the Integral Cylindrical Cyclone and Loopseal (ICCL), and also describes its performance as demonstrated in a CFB cold flow model incorporating the new apparatus. The commercial application of the ICCL in a 1.2 MM lb steam/hr CFB boiler as well as its potential application in reheat CFB units are also discussed.

  8. DESIGN AND DEVELOPMENT OF GAS-LIQUID CYLINDRICAL CYCLONE COMPACT SEPARATORS FOR THREE-PHASE FLOW

    SciTech Connect

    Dr. Ram S. Mohan; Dr. Ovadia Shoham

    2001-04-30

    This report presents a brief overview of the activities and tasks accomplished during the first half year (October 1, 2000-March 31, 2001) of the fourth project year budget period (October 1, 2000-September 30, 2001). An executive summary is presented initially followed by the tasks of the current budget period. Then, detailed description of the experimental and modeling investigations are presented. Subsequently, the technical and scientific results of the activities of this project period are presented with some discussions. The findings of this investigation are summarized in the ''Conclusions'' section followed by relevant references. The fourth project year activities are divided into three main parts, which are carried out in parallel. The first part is continuation of the experimental program that includes a study of the oil/water two-phase behavior at high pressures and control system development for the three-phase GLCC{copyright}. This investigation will be eventually extended for three-phase flow. The second part consists of the development of a simplified mechanistic model incorporating the experimental results and behavior of dispersion of oil in water and water in oil. This will provide an insight into the hydrodynamic flow behavior and serve as the design tool for the industry. Although useful for sizing GLCC{copyright} for proven applications, the mechanistic model will not provide detailed hydrodynamic flow behavior information needed to screen new geometric variations or to study the effect of fluid property variations. Therefore, in the third part, the more rigorous approach of computational fluid dynamics (CFD) will be utilized. Multidimensional multiphase flow simulation at high pressures and for real crude conditions will provide much greater depth into the understanding of the physical phenomena and the mathematical analysis of three-phase GLCC{copyright} design and performance.

  9. DESIGN AND DEVELOPMENT OF GAS-LIQUID CYLINDRICAL CYCLONE COMPACT SEPARATORS FOR THREE-PHASE FLOW

    SciTech Connect

    Dr. Ram S. Mohan; Dr. Ovadia Shoham

    2001-10-30

    This report presents a brief overview of the activities and tasks accomplished during the second half year (April 1, 2001-September 30, 2001) of the fourth project year budget period (October 1, 2000-September 30, 2001). An executive summary is presented initially followed by the tasks of the current budget period. Then, detailed description of the experimental and modeling investigations are presented. Subsequently, the technical and scientific results of the activities of this project period are presented with some discussions. The findings of this investigation are summarized in the ''Conclusions'' section followed by relevant references. The fourth project year activities are divided into three main parts, which are carried out in parallel. The first part is continuation of the experimental program that includes a study of the oil/water two-phase behavior at high pressures and control system development for the three-phase GLCC{copyright}. This investigation will be eventually extended for three-phase flow. The second part consists of the development of a simplified mechanistic model incorporating the experimental results and behavior of dispersion of oil in water and water in oil. This will provide an insight into the hydrodynamic flow behavior and serve as the design tool for the industry. Although useful for sizing GLCC{copyright} for proven applications, the mechanistic model will not provide detailed hydrodynamic flow behavior information needed to screen new geometric variations or to study the effect of fluid property variations. Therefore, in the third part, the more rigorous approach of computational fluid dynamics (CFD) will be utilized. Multidimensional multiphase flow simulation at high pressures and for real crude conditions will provide much greater depth into the understanding of the physical phenomena and the mathematical analysis of three-phase GLCC{copyright} design and performance.

  10. DESIGN AND DEVELOPMENT OF GAS-LIQUID CYLINDRICAL CYCLONE COMPACT SEPARATORS FOR THREE-PHASE FLOW

    SciTech Connect

    Dr. Ram S. Mohan; Dr. Ovadia Shoham

    2002-04-29

    This report presents a brief overview of the activities and tasks accomplished during the first half year (October 1, 2001--March 31, 2002) of the fifth project year budget period (October 1, 2001--September 30, 2002). An executive summary is presented initially followed by the tasks of the current budget period. Then, detailed description of the experimental and modeling investigations are presented. Subsequently, the technical and scientific results of the activities of this project period are presented with some discussions. The findings of this investigation are summarized in the ''Conclusions'' section followed by relevant references. The fifth project year activities are divided into three main parts, which are carried out in parallel. The first part is continuation of the experimental program that includes a study of the oil/water two-phase behavior at high pressures and control system development for the two-phase LLCC{copyright}. This investigation has been extended for three-phase GLCC as well. The second part consists of the development of a simplified mechanistic model incorporating the experimental results and behavior of dispersion of oil in water and water in oil. This will provide an insight into the hydrodynamic flow behavior and serve as the design tool for the industry. Although useful for sizing GLCC{copyright} for proven applications, the mechanistic model will not provide detailed hydrodynamic flow behavior information needed to screen new geometric variations or to study the effect of fluid property variations. Hence it will be validated with a more rigorous approach of computational fluid dynamics (CFD) simulation. Multidimensional multiphase flow simulation at high pressures and for real crude conditions will provide much greater depth into the understanding of the physical phenomena and the mathematical analysis of three-phase GLCC{copyright} design and performance. In the third part, design guidelines for three-phase GLCC{copyright} field applications by the industry will be developed. These design guidelines will form the basis for high-pressure real crude conditions.

  11. Helical solutions of the bidirectional vortex in a cylindrical cyclone: Beltramian and Trkalian motions

    NASA Astrophysics Data System (ADS)

    Majdalani, Joseph

    2012-10-01

    In this work, two families of helical motions are investigated as prospective candidates for describing the bidirectional vortex field in a right-cylindrical chamber. These basic solutions are relevant to cyclone separators and to idealized representations of vortex-fired liquid and hybrid rocket engines in which bidirectional vortex motion is established. To begin, the bulk fluid motion is taken to be isentropic along streamlines, with no concern for reactions, heat transfer, viscosity, compressibility or unsteadiness. Then using the Bragg-Hawthorne equation for steady, inviscid, axisymmetric motion, two families of Euler solutions are derived. Among the characteristics of the newly developed solutions one may note the axial dependence of the swirl velocity, the Trkalian and Beltramian types of the helical motions, the sensitivity of the solutions to the outlet radius, the alternate locations of the mantle, and the increased axial and radial velocity magnitudes, including the rate of mass transfer across the mantle, for which explicit approximations are obtained. Our results are compared to an existing, complex lamellar model of the bidirectional vortex in which the swirl velocity reduces to a free vortex. In this vein, we find the strictly Beltramian flows to share virtually identical pressure variations and radial pressure gradients with those associated with the complex lamellar motion. Furthermore, both families warrant an asymptotic treatment to overcome their endpoint limitations caused by their omission of viscous stresses. From a broader perspective, the work delineates a logical framework through which self-similar, axisymmetric solutions to bidirectional and multidirectional vortex motions may be pursued. It also illustrates the manner through which different formulations may be arrived at depending on the types of wall boundary conditions. For example, both the slip condition at the sidewall and the inlet flow pattern at the headwall may be enforced or

  12. Advances in gas-liquid flows 1990

    SciTech Connect

    Kim, J.M. . Nuclear Reactor Lab.); Rohatgi, U.S. ); Hashemi, A. )

    1990-01-01

    Gas-liquid two-phase flows commonly occur in nature and industrial applications. Rain, clouds, geysers, and waterfalls are examples of natural gas-liquid flow phenomena, whereas industrial applications can be found in nuclear reactors, steam generators, boilers, condensers, evaporators, fuel atomization, heat pipes, electronic equipment cooling, petroleum engineering, chemical process engineering, and many others. The household-variety phenomena such as garden sprinklers, shower, whirlpool bath, dripping faucet, boiling tea pot, and bubbling beer provide daily experience of gas-liquid flows. The papers presented in this volume reflect the variety and richness of gas-liquid two-phase flow and the increasing role it plays in modern technology. This volume contains papers dealing with some recent development in gas-liquid flow science and technology, covering basic gas-liquid flows, measurements and instrumentation, cavitation and flashing flows, countercurrent flow and flooding, flow in various components and geometries liquid metals and thermocapillary effects, heat transfer, nonlinear phenomena, instability, and other special and general topics related to gas-liquid flows.

  13. New trends in the improvement of cyclones

    SciTech Connect

    Rivkinzon, I.B.; Zyuba, B.I.

    1984-05-01

    This article examines the possibilities of reducing catalyst attrition and cyclone wall erosion through optimization of the aerodynamic conditions in the cyclone. It is assumed that the disintegration of catalyst particles and erosion of the cyclone walls take place at exactly the same points (e.g. the seats of erosion in the cyclones can serve as natural indicators in determining the zones of catalyst pulverization). In catalytic cracking units, internal cyclones are used as the primary means of cleanup of the gas for process purposes. Cyclones trap out 99.8-99.95% of the catalyst entrained from the fluidized bed by the contact gas. The retrofitting of standard cyclones with chambers for preliminary aerodynamic stabilization of the flow yielded favorable results. The results of erosion tests on type TsN cyclones with and without a stabilization chamber indicate that the proposed stabilization method can give an approximately fivefold reduction of erosion of the cylindrical part of the cyclone. An important advantage of cyclones with added stabilization is the increased efficiency of dust collection. It is concluded that supplementary aerodynamic stabilization of the dust-laded gas flow and reduction of the angle of attack can give substantial improvements in the operating characteristics of cyclones, both cylindrical and spiral-conical.

  14. Cyclone reactor

    DOEpatents

    Converse, Alvin O.; Grethlein, Hans E.; Holland, Joseph E.

    1989-04-04

    A system is provided to produce sugars from a liquid-solid mixture containing biomass, and an acid, wherein the mixture is heated to an appropriate temperature to achieve hydrolysis. The liquid-solid mixture is introduced as a stream into the circular-cylindrical chamber of a cyclone reaction vessel and steam is introduced to the vessel to provide the necessary heat for hydrolysis as well as to establish the liquid-solid mixture in a rotary flow field whereby the liquids and solids of the mixture move along spiral paths within the chamber. The liquid-solid mixture may be introduced at the periphery of the chamber to spiral down toward and be discharged at or near the center of the chamber. Because of differing mass, the solid particles in the mixture move radially inward at a different rate than the liquid and that rate is controlled to maximize the hydrolysis of the solids and to minimize the decomposition of sugars, thus formed.

  15. Axisymmetric structure of the long lasting summer Arctic cyclones

    NASA Astrophysics Data System (ADS)

    Aizawa, Takuro; Tanaka, H. L.

    2016-09-01

    Arctic cyclones are unique low pressure systems in the Arctic, which are different from the tropical cyclones and the mid-latitude cyclones. The axisymmetric structures of two major Arctic cyclones which appeared in June 2008 and August 2012 are examined based on the cylindrical coordinate system around the Arctic cyclone. The result demonstrates that the Arctic cyclone has a deep barotropic cyclonic circulation, a secondary circulation in the troposphere, a downdraft at the lower stratosphere, a coupling of a warm core at the lower stratosphere and a cold core in the troposphere, and a deep tropopause folding over the cyclone center. The horizontal scale of the Arctic cyclone reaches 5000 km in diameter which is one of the largest cyclones found on the Earth. Note that the cyclone of June 2008 appears showing axisymmetric cyclonic circulations at the surface level. The cyclone of 2012 is characterized by the structure change from the cold core to the warm core at the lower stratosphere, indicating a shift from the ordinary baroclinic cyclone to the typical Arctic cyclone. Although additional studies are needed, a schematic diagram of the Arctic cyclone is proposed in this study.

  16. Supersonic Gas-Liquid Cleaning System

    NASA Technical Reports Server (NTRS)

    Kinney, Frank

    1996-01-01

    The Supersonic Gas-Liquid Cleaning System Research Project consisted mainly of a feasibility study, including theoretical and engineering analysis, of a proof-of-concept prototype of this particular cleaning system developed by NASA-KSC. The cleaning system utilizes gas-liquid supersonic nozzles to generate high impingement velocities at the surface of the device to be cleaned. The cleaning fluid being accelerated to these high velocities may consist of any solvent or liquid, including water. Compressed air or any inert gas is used to provide the conveying medium for the liquid, as well as substantially reduce the total amount of liquid needed to perform adequate surface cleaning and cleanliness verification. This type of aqueous cleaning system is considered to be an excellent way of conducting cleaning and cleanliness verification operations as replacements for the use of CFC 113 which must be discontinued by 1995. To utilize this particular cleaning system in various cleaning applications for both the Space Program and the commercial market, it is essential that the cleaning system, especially the supersonic nozzle, be characterized for such applications. This characterization consisted of performing theoretical and engineering analysis, identifying desirable modifications/extensions to the basic concept, evaluating effects of variations in operating parameters, and optimizing hardware design for specific applications.

  17. Supersonic gas-liquid cleaning system

    NASA Astrophysics Data System (ADS)

    Caimi, Raoul E. B.; Thaxton, Eric A.

    1994-02-01

    A system to perform cleaning and cleanliness verification is being developed to replace solvent flush methods using CFC 113 for fluid system components. The system is designed for two purposes: internal and external cleaning and verification. External cleaning is performed with the nozzle mounted at the end of a wand similar to a conventional pressure washer. Internal cleaning is performed with a variety of fixtures designed for specific applications. Internal cleaning includes tubes, pipes, flex hoses, and active fluid components such as valves and regulators. The system uses gas-liquid supersonic nozzles to generate high impingement velocities at the surface of the object to be cleaned. Compressed air or any inert gas may be used to provide the conveying medium for the liquid. The converging-diverging nozzles accelerate the gas-liquid mixture to supersonic velocities. The liquid being accelerated may be any solvent including water. This system may be used commercially to replace CFC and other solvent cleaning methods widely used to remove dust, dirt, flux, and lubricants. In addition, cleanliness verification can be performed without the solvents which are typically involved. This paper will present the technical details of the system, the results achieved during testing at KSC, and future applications for this system.

  18. Supersonic gas-liquid cleaning system

    NASA Technical Reports Server (NTRS)

    Caimi, Raoul E. B.; Thaxton, Eric A.

    1994-01-01

    A system to perform cleaning and cleanliness verification is being developed to replace solvent flush methods using CFC 113 for fluid system components. The system is designed for two purposes: internal and external cleaning and verification. External cleaning is performed with the nozzle mounted at the end of a wand similar to a conventional pressure washer. Internal cleaning is performed with a variety of fixtures designed for specific applications. Internal cleaning includes tubes, pipes, flex hoses, and active fluid components such as valves and regulators. The system uses gas-liquid supersonic nozzles to generate high impingement velocities at the surface of the object to be cleaned. Compressed air or any inert gas may be used to provide the conveying medium for the liquid. The converging-diverging nozzles accelerate the gas-liquid mixture to supersonic velocities. The liquid being accelerated may be any solvent including water. This system may be used commercially to replace CFC and other solvent cleaning methods widely used to remove dust, dirt, flux, and lubricants. In addition, cleanliness verification can be performed without the solvents which are typically involved. This paper will present the technical details of the system, the results achieved during testing at KSC, and future applications for this system.

  19. Cyclone Monty

    Atmospheric Science Data Center

    2013-04-16

    ... traveling inland about 300 kilometers to the south, the cyclonic circulation had decayed considerably, although category 3 force winds ... project:  MISR category:  gallery Storms date:  Feb 29 and Mar 4, 2004 Images:  ...

  20. Gas-Liquid Processing in Microchannels

    SciTech Connect

    TeGrotenhuis, Ward E.; Stenkamp, Victoria S.; Twitchell, Alvin

    2005-09-01

    Processing gases and liquids together in microchannels having at least one dimension <1 mm has unique advantages for rapid heat and mass transfer. One approach for managing the two phases is to use porous structures as wicks within microchannels to segregate the liquid phase from the gas phase. Gas-liquid processing is accomplished by providing a gas flow path and inducing flow of the liquid phase through or along the wick under an induced pressure gradient. A variety of unit operations are enabled, including phase separation, partial condensation, absorption, desorption, and distillation. Results are reported of an investigation of microchannel phase separation in a transparent, single-channel device. Next, heat exchange is integrated with the microchannel wick approach to create a partial condenser that also separates the condensate. Finally, the scale-up to a multi-channel phase separator is described.

  1. Gas-Liquid Flow in Pipelines

    SciTech Connect

    Thomas J. Hanratty

    2005-02-25

    A research program was carried out at the University of Illinois in which develops a scientific approach to gas-liquid flows that explains their macroscopic behavior in terms of small scale interactions. For simplicity, fully-developed flows in horizontal and near-horizontal pipes. The difficulty in dealing with these flows is that the phases can assume a variety of configurations. The specific goal was to develop a scientific understanding of transitions from one flow regime to another and a quantitative understanding of how the phases distribute for a give regime. These basic understandings are used to predict macroscopic quantities of interest, such as frictional pressure drop, liquid hold-up, entrainment in annular flow and frequency of slugging in slug flows. A number of scientific issues are addressed. Examples are the rate of atomization of a liquid film, the rate of deposition of drops, the behavior of particles in a turbulent field, the generation and growth of interfacial waves. The use of drag-reducing polymers that change macroscopic behavior by changing small scale interactions was explored.

  2. Mixed Stationary Liquid Phases for Gas-Liquid Chromatography.

    ERIC Educational Resources Information Center

    Koury, Albert M.; Parcher, Jon F.

    1979-01-01

    Describes a laboratory technique for use in an undergraduate instrumental analysis course that, using the interpretation of window diagrams, prepares a mixed liquid phase column for gas-liquid chromatography. A detailed procedure is provided. (BT)

  3. Gas-liquid separator and method of operation

    DOEpatents

    Soloveichik, Grigorii Lev; Whitt, David Brandon

    2009-07-14

    A system for gas-liquid separation in electrolysis processes is provided. The system includes a first compartment having a liquid carrier including a first gas therein and a second compartment having the liquid carrier including a second gas therein. The system also includes a gas-liquid separator fluidically coupled to the first and second compartments for separating the liquid carrier from the first and second gases.

  4. Post Cyclone (PoC): An innovative way to reduce the emission of fines from industrial cyclones

    SciTech Connect

    Ray, M.B.; Luning, P.E.; Hoffmann, A.C.; Plomp, A.; Beumer, M.I.L.

    1997-07-01

    A novel approach for reducing the emission of industrial-scale cyclones of particles smaller than 10 {micro}m is presented. Utilizing the strong swirl already present in the vortex finder of a conventional cyclone, the escaped dust from the cyclone is collected in a so-called Post Cyclone (PoC), which is a cylindrical annular shell located on top of the vortex finder. Experiments were conducted in a cyclone larger than the usual laboratory range (diameter = 0.4 m) with different configurations of the PoC and spanning a range of operating conditions. Flow patterns and collection efficiencies for the cyclone and the PoC, both individually and in combination, were calculated and compared with experimental data. Both the experiments and simulations indicate a decrease in emission of particles of 1--3 {micro}m by around 30%, rising with particle size to around 50% for 5 {micro}m particles.

  5. Computer code for gas-liquid two-phase vortex motions: GLVM

    NASA Technical Reports Server (NTRS)

    Yeh, T. T.

    1986-01-01

    A computer program aimed at the phase separation between gas and liquid at zero gravity, induced by vortex motion, is developed. It utilizes an explicit solution method for a set of equations describing rotating gas-liquid flows. The vortex motion is established by a tangential fluid injection. A Lax-Wendroff two-step (McCormack's) numerical scheme is used. The program can be used to study the fluid dynamical behavior of the rotational two-phase fluids in a cylindrical tank. It provides a quick/easy sensitivity test on various parameters and thus provides the guidance for the design and use of actual physical systems for handling two-phase fluids.

  6. Dispersed bubble reactor for enhanced gas-liquid-solids contact and mass transfer

    DOEpatents

    Vimalchand, Pannalal; Liu, Guohai; Peng, WanWang; Bonsu, Alexander

    2016-01-26

    An apparatus to promote gas-liquid contact and facilitate enhanced mass transfer. The dispersed bubble reactor (DBR) operates in the dispersed bubble flow regime to selectively absorb gas phase constituents into the liquid phase. The dispersion is achieved by shearing the large inlet gas bubbles into fine bubbles with circulating liquid and additional pumped liquid solvent when necessary. The DBR is capable of handling precipitates that may form during absorption or fine catalysts that may be necessary to promote liquid phase reactions. The DBR can be configured with multistage counter current flow sections by inserting concentric cylindrical sections into the riser to facilitate annular flow. While the DBR can absorb CO.sub.2 in liquid solvents that may lead to precipitates at high loadings, it is equally capable of handling many different types of chemical processes involving solids (precipitates/catalysts) along with gas and liquid phases.

  7. Injector design guidelines for gas/liquid propellant systems

    NASA Technical Reports Server (NTRS)

    Falk, A. Y.; Burick, R. J.

    1973-01-01

    Injector design guidelines are provided for gas/liquid propellant systems. Information was obtained from a 30-month applied research program encompassing an analytical, design, and experimental effort to relate injector design parameters to simultaneous attainment of high performance and component (injector/thrust chamber) compatibility for gas/liquid space storable propellants. The gas/liquid propellant combination studied was FLOX (82.6% F2)/ ambient temperature gaseous methane. Design criteria that provide for simultaneous attainment of high performance and chamber compatibility are presented for both injector types. Parametric data are presented that are applicable for the design of circular coaxial and like-doublet injectors that operate with design parameters similar to those employed. However, caution should be exercised when applying these data to propellant combinations whose elements operate in ranges considerably different from those employed in this study.

  8. A Lab Experiment to Introduce Gas/Liquid Solubility

    ERIC Educational Resources Information Center

    Fonsecaa, I. M. A.; Almeida, J. P. B.; Fachada, H. C.

    2008-01-01

    A simplified version of a volumetric apparatus for gas/liquid solubility measurements is proposed. The procedure familiarizes undergraduate students with the experimental study of the solubility of a gas in a liquid and contributes to the understanding of this important phase equilibrium concept. The experimental results report the determination…

  9. Parallel magnetic resonance imaging of gas-liquid flows

    NASA Astrophysics Data System (ADS)

    Mueller, Christoph; Penn, Alexander; Pruessmann, Klaas P.

    2015-03-01

    Gas-liquids flows are commonly encountered in nature and industry. Experimental measurements of gas-liquid flows are challenging since such systems can be visually opaque and highly dynamic. Here we report the implementation of advanced magnetic resonance imaging (MRI) strategies allowing us to probe the dynamics (voidage and velocity measurements) of gas-liquid flows with ultra-fast acquisition speeds. Specifically, parallel MRI which exploits the spatial encoding capabilities of multiple receiver coils was implemented. To this end a tailored, 16 channels MR receive array was constructed and employed in the MR acquisition. A magnetic susceptibility matched gas-liquid system was set-up and used to probe the motion, splitting and coalescence of bubbles. The temporal and spatial resolution of our acquired data was 5 ms and 3.5 mm x 3.5 mm, respectively. The total field of view was 200 mm x 200 mm. We will conclude with an outlook of further possible advances in MRI that have the potential to reduce substantially the acquisition time, providing flexible gains in temporal and spatial resolution.

  10. 21 CFR 862.2250 - Gas liquid chromatography system for clinical use.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Gas liquid chromatography system for clinical use... Instruments § 862.2250 Gas liquid chromatography system for clinical use. (a) Identification. A gas liquid chromatography system for clinical use is a device intended to separate one or more drugs or compounds from...

  11. 21 CFR 862.2250 - Gas liquid chromatography system for clinical use.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Gas liquid chromatography system for clinical use... Instruments § 862.2250 Gas liquid chromatography system for clinical use. (a) Identification. A gas liquid chromatography system for clinical use is a device intended to separate one or more drugs or compounds from...

  12. 21 CFR 862.2250 - Gas liquid chromatography system for clinical use.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Gas liquid chromatography system for clinical use... Instruments § 862.2250 Gas liquid chromatography system for clinical use. (a) Identification. A gas liquid chromatography system for clinical use is a device intended to separate one or more drugs or compounds from...

  13. 21 CFR 862.2250 - Gas liquid chromatography system for clinical use.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Gas liquid chromatography system for clinical use... Instruments § 862.2250 Gas liquid chromatography system for clinical use. (a) Identification. A gas liquid chromatography system for clinical use is a device intended to separate one or more drugs or compounds from...

  14. 21 CFR 862.2250 - Gas liquid chromatography system for clinical use.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Gas liquid chromatography system for clinical use... Instruments § 862.2250 Gas liquid chromatography system for clinical use. (a) Identification. A gas liquid chromatography system for clinical use is a device intended to separate one or more drugs or compounds from...

  15. Hydrocarbon Gas Liquids (HGL): Recent Market Trends and Issues

    EIA Publications

    2014-01-01

    Over the past five years, rapid growth in U.S. onshore natural gas and oil production has led to increased volumes of natural gas plant liquids (NGPL) and liquefied refinery gases (LRG). The increasing economic importance of these volumes, as a result of their significant growth in production, has revealed the need for better data accuracy and transparency to improve the quality of historical data and projections for supply, demand, and prices of these liquids, co-products, and competing products. To reduce confusion in terminology and improve its presentation of data, EIA has worked with industry and federal and state governments to clarify gas liquid terminology and has developed the term Hydrocarbon Gas Liquids, or HGL.

  16. Optimum design of space storable gas/liquid coaxial injectors.

    NASA Technical Reports Server (NTRS)

    Burick, R. J.

    1972-01-01

    Review of the results of a program of single-element, cold-flow/hot-fire experiments performed for the purpose of establishing design criteria for a high-performance gas/liquid (FLOX/CH4) coaxial injector. The approach and the techniques employed resulted in the direct design of an injector that met or exceeded the performance and chamber compatibility goals of the program without any need for the traditional 'cut-and-try' development methods.

  17. Experience with different cyclones in CFBs

    SciTech Connect

    Alliston, M.G.; Brink, K.E.; Kokko, A.

    1998-07-01

    Kvaerner Pulping has been designing, manufacturing and delivering different kinds of CFB boilers since the beginning of the 1980s. This paper gives a historical overview of these first generation CFBs and especially operational experience with them. Due to some specific problems in these first generation CFBs, described in this paper, Kvaerner Pulping was among the pioneers in CFB construction development and was probably the first company to deliver a totally water-cooled CFB construction that also included the cyclone. The goal in construction development has been to improve the reliability of the CFB boiler and at the same time minimizing the required service time. Kvaerner's continuous CFB development has created several constructions with different appearances for different applications. The basic development work has been done on the conventional cyclone type and this it is still the most common cyclone type used in all sizes of applications. CYMIC boiler, and especially its cyclone, is one of the new designs. It is also a totally water-cooled construction and it has some additional benefits which are mainly correlated with the space requirements of boiler placement and simple cyclone construction. CYMIC is very suitable for industrial applications and for cases where utilizes existing boiler houses or parts of them are being utilized. For the increased CFB boiler sizes Kvaerner has developed the ICCL (Integral Cylindrical Cyclone and Loop-seal). Again the installation is totally water-cooled and additional benefits are related to the straight cyclone construction, water-cooled vortex finder the ability to locate a significant proportion of heat surfaces in the loopseal. All the constructional features mentioned above are described in detail in this paper. This present paper gives some idea of how these installations have coped in practice and what aspects need to be developed further.

  18. Cylindrical wormholes

    SciTech Connect

    Bronnikov, K. A.; Lemos, Jose P. S.

    2009-05-15

    It is shown that the existence of static, cylindrically symmetric wormholes does not require violation of the weak or null energy conditions near the throat, and cylindrically symmetric wormhole geometries can appear with less exotic sources than wormholes whose throats have a spherical topology. Examples of exact wormhole solutions are given with scalar, spinor and electromagnetic fields as sources, and these fields are not necessarily phantom. In particular, there are wormhole solutions for a massless, minimally coupled scalar field in the presence of a negative cosmological constant, and for an azimuthal Maxwell electromagnetic field. All these solutions are not asymptotically flat. A no-go theorem is proved, according to which a flat (or string) asymptotic behavior on both sides of a cylindrical wormhole throat is impossible if the energy density of matter is everywhere nonnegative.

  19. Improved water-cooled cyclone constructions in CFBs

    SciTech Connect

    Alliston, M.G.; Luomaharju, T.; Kokko, A.

    1999-07-01

    The construction of CFB boilers has advanced in comparison with early designs. One improvement has been the use of water or steam cooled cyclones, which allows the use of thin refractories and minimizes maintenance needs. Cooled cyclones are also tolerant of wide load variations when the main fuel is biologically based, and coal or some other fuel is used as a back-up. With uncooled cyclones, load changes with high volatile fuels can mean significant temperature transients in the refractory, due to post-combustion phenomena in the cyclone. Kvaerner's development of water-cooled cyclones for CFBs began in the early 1980s. The first boiler with this design was delivered in 1985 in Sweden. Since then, Kvaerner Pulping has delivered over twenty units with cooled cyclones, in capacity ranging from small units up to 400 MW{sub th}. Among these units, Kvaerner has developed unconventional solutions for CFBs, in order to simplify the constructions and to increase the reliability for different applications. The first of them was CYMIC{reg{underscore}sign}, which has its water-cooled cyclone built inside the boiler furnace. There are two commercial CYMIC boilers in operation and one in project stages. The largest CYMIC in operation is a 185 MW{sub th} industrial boiler burning various fuels. For even larger scale units Kvaerner developed the Integrated Cylindrical Cyclone and Loopseal (ICCL) assembly. One of these installations is in operation in USA, having steaming capacity of over 500 t/h. The design bases of these new solutions are quite different in comparison with conventional cyclones. Therefore, an important part of the development has been cold model testing and mathematical modeling of the cyclones. This paper reviews the state-of-the-art in water-cooled cyclone construction. The new solutions, their full-scale experience, and a comparison of the actual experience with the preliminary modeling work are introduced.

  20. Optimization of Geometric Parameters of the Cyclone Apparatus Based on its Numerical Modeling

    NASA Astrophysics Data System (ADS)

    Biryuk, V. V.; Gorshkalev, A. A.; Tsapkova, A. B.; Shimanov, A. A.; Blagin, E. V.

    2017-01-01

    This article deals with a cyclone cleaner which separates solid particles from the gas. The influence of the input duct angle and the relation of the conical part of the apparatus to a cylindrical one on the cleaning degree were investigated. 3-d models of the flow channel of the opposite-flow cyclone with input duct angles varied from 0 to 40° and conical and cylindrical parts relation from 2:3 to 4:1 were considered. Numerical modelling of a soot clearing process in the opposite-flow cyclone was carried out in the ANSYS Fluent software. The results of 25 different models are presented.

  1. Coal desulfurization by cyclonic whirl

    SciTech Connect

    Jianguo, Y.; Wenjun, Z.; Yuling, W.

    1999-07-01

    The crux of coal desulfurization is how to improve separation efficiency for 3--0.1mm materials. Cyclonic whirl produce centrifugal force and shearing force, heavy medium cyclone uses former, and cyclone flotation column uses both of them. A new system with heavy medium cyclone and cyclone flotation column is provided and testified to be very efficient in commercial desulfurization.

  2. Gas-liquid chromatography in lunar organic analysis.

    NASA Technical Reports Server (NTRS)

    Gehrke, C. W.

    1972-01-01

    Gas-liquid chromatography (GLC) is a powerful and sensitive method for the separation and detection of organic compounds at nanogram levels. The primary requirement for successful analyses is that the compounds of interest must be volatile under the chromatographic conditions employed. Nonvolatile organic compounds must be converted to volatile derivatives prior to analysis. The derivatives of choice must be both amenable to chromatographic separation and be relatively stable. The condition of volatility necessitates the development of efficient derivatization reactions for important groups of compounds as amino acids, carbohydrates, nucleosides, etc. Trimethylsilylation and trifluoroacetylation represent specific areas of recent prominence. Some relevant practical aspects of GLC are discussed.

  3. About the statistical description of gas-liquid flows

    SciTech Connect

    Sanz, D.; Guido-Lavalle, G.; Carrica, P.

    1995-09-01

    Elements of the probabilistic geometry are used to derive the bubble coalescence term of the statistical description of gas liquid flows. It is shown that the Boltzmann`s hypothesis, that leads to the kinetic theory of dilute gases, is not appropriate for this kind of flows. The resulting integro-differential transport equation is numerically integrated to study the flow development in slender bubble columns. The solution remarkably predicts the transition from bubbly to slug flow pattern. Moreover, a bubbly bimodal size distribution is predicted, which has already been observed experimentally.

  4. Tropical Cyclone Report, 1993

    DTIC Science & Technology

    1993-01-01

    Office of Naval Research (;rant AN00014-914J1721 STAFF JOINT TYPHOON WARNING CENTER LCDR ANTHONY A. MARTINEZ USN TDO. DEPUTY DIRECTOR LCDR TERESA M...OEJFN TDA. GRAPHICS AGAN ANDRESG.GRANT USN TDA, GRAPHICS UNIVERSITY OF GUAM / JTWC RESEARCH LIAISON DR MARK A. LANDER TROPICAL CYCLONE RESEARCH MR...CHARLES P. GUARD TROPICAL CYCLONE RESEARCH * TRANSFERRED DURING 1993 ** ACTIVE DUTY TRAINING S~ii FOREWORD The Annual Tropical Cyclone Report is past four

  5. Cyclone performance and optimization

    SciTech Connect

    Leith, D.

    1990-09-15

    The objectives of this project are: to characterize the gas flow pattern within cyclones, to revise the theory for cyclone performance on the basis of these findings, and to design and test cyclones whose dimensions have been optimized using revised performance theory. This work is important because its successful completion will aid in the technology for combustion of coal in pressurized, fluidized beds. This quarter, an empirical model for predicting pressure drop across a cyclone was developed through a statistical analysis of pressure drop data for 98 cyclone designs. The model is shown to perform better than the pressure drop models of First (1950), Alexander (1949), Barth (1956), Stairmand (1949), and Shepherd-Lapple (1940). This model is used with the efficiency model of Iozia and Leith (1990) to develop an optimization curve which predicts the minimum pressure drop and the dimension rations of the optimized cyclone for a given aerodynamic cut diameter, d{sub 50}. The effect of variation in cyclone height, cyclone diameter, and flow on the optimization curve is determined. The optimization results are used to develop a design procedure for optimized cyclones. 37 refs., 10 figs., 4 tabs.

  6. Cyclone performance and optimization

    SciTech Connect

    Leith, D.

    1989-03-15

    The objectives of this project are: to characterize the gas flow pattern within cyclones, to revise the theory for cyclone performance on the basis of these findings, and to design and test cyclones whose dimensions have been optimized using revised performance theory. This work is important because its successful completion will aid in the technology for combustion of coal in pressurized, fluidized beds. This quarter, we have been hampered somewhat by flow delivery of the bubble generation system and arc lighting system placed on order last fall. This equipment is necessary to map the flow field within cyclones using the techniques described in last quarter's report. Using the bubble generator, we completed this quarter a study of the natural length'' of cyclones of 18 different configurations, each configuration operated at five different gas flows. Results suggest that the equation by Alexander for natural length is incorrect; natural length as measured with the bubble generation system is always below the bottom of the cyclones regardless of the cyclone configuration or gas flow, within the limits of the experimental cyclones tested. This finding is important because natural length is a term in equations used to predict cyclone efficiency. 1 tab.

  7. Gas-liquid Phase Distribution and Void Fraction Measurements Using the MRI

    NASA Technical Reports Server (NTRS)

    Daidzic, N. E.; Schmidt, E.; Hasan, M. M.; Altobelli, S.

    2004-01-01

    We used a permanent-magnet MRI system to estimate the integral and spatially- and/or temporally-resolved void-fraction distributions and flow patterns in gas-liquid two-phase flows. Air was introduced at the bottom of the stagnant liquid column using an accurate and programmable syringe pump. Air flow rates were varied between 1 and 200 ml/min. The cylindrical non-conducting test tube in which two-phase flow was measured was placed in a 2.67 kGauss MRI with MRT spectrometer/imager. Roughly linear relationship has been obtained for the integral void-fraction, obtained by volume-averaging of the spatially-resolved signals, and the air flow rate in upward direction. The time-averaged spatially-resolved void fraction has also been obtained for the quasi-steady flow of air in a stagnant liquid column. No great accuracy is claimed as this was an exploratory proof-of-concept type of experiment. Preliminary results show that MRI a non-invasive and non-intrusive experimental technique can indeed provide a wealth of different qualitative and quantitative data and is especially well suited for averaged transport processes in adiabatic and diabatic multi-phase and/or multi-component flows.

  8. Vibration-Induced Gas-Liquid Interface Breakup

    NASA Astrophysics Data System (ADS)

    O'Hern, Timothy; Torczynski, John; Romero, Ed; Shelden, Bion

    2010-11-01

    Gas-liquid interfaces can be forced to break up when subjected to vibrations within critical ranges of frequency and amplitude. This breakup mechanism was examined experimentally using deep layers of silicone oils over a range of viscosity and sinusoidal, primarily axial vibration conditions that can produce dramatic disturbances at the gas-liquid free surface. Although small-amplitude vibrations produce standing Faraday waves, large-amplitude vibrations produce liquid jets into the gas, droplets pinching off from the jets, gas cavities in the liquid from droplet impact, and bubble transport below the interface. Experiments used several different silicone oils over a range of pressures and vibration conditions. Computational simulations exhibiting similar behavior will be included in the presentation. Applications include liquid fuel rockets, inertial sensing devices, moving vehicles, mixing processes, and acoustic excitation. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  9. Cyclone performance by velocity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cyclones are used almost exclusively in the US cotton ginning industry for emission abatement on pneumatic conveying system exhausts because of their high efficiency, and low capital and operating cost.. Cyclone performance is improved by increasing collection effectiveness or decreasing energy cons...

  10. Identification of polychlorinated styrene compounds in heron tissues by gas-liquid chromatography-mass spectrometry.

    PubMed

    Reichel, W L; Prouty, R M; Gay, M L

    1977-01-01

    Unknown compounds detected in Ardea herodias tissues are identified by gas-liquid chromatography-mass spectrometry as residues of octachlorostyrene. Heptachlorostyrene and hexachlorostyrene were tentatively identified.

  11. Identification of polychlorinated styrene compounds in heron tissues by gas-liquid chromatography-mass spectrometry

    USGS Publications Warehouse

    Reichel, W.L.; Prouty, R.M.; Gay, M.L.

    1977-01-01

    Unknown compounds detected in Ardea herodias tissues are identified by gas-liquid chromatography-mass spectrometry as residues of octachlorostyrene. Heptachlorostyrene and hexachlorostyrene were tentatively identified.

  12. Understand cyclone design

    SciTech Connect

    Coker, A.K. )

    1993-12-01

    Cyclones are widely used for the separation and recovery of industrial dusts from air or process gases. Cyclones are the principal type of gas-solids separator using centrifugal force. They are simple to construct, of low cost, and are made from a wide range of materials with an ability to operate at high temperatures and pressure. Cyclones are suitable for separating particles where agglomeration occurs. Pollution and emission regulations have compelled designers to study the efficiency of cyclones. Cyclones offer the least expensive means of dust collection. They give low efficiency for collection of particles smaller than 5 [mu]m. A high efficiency of 98% can be achieved on dusts with particle sizes of 0.1 to 0.2 [mu]m that are highly flocculated. The paper discusses the design procedure and operating parameters.

  13. Cyclone performance and optimization

    SciTech Connect

    Leith, D.

    1989-06-15

    The objectives of this project are: to characterize the gas flow pattern within cyclones, to revise the theory for cyclone performance on the basis of these findings, and to design and test cyclones whose dimensions have been optimized using revised performance theory. This work is important because its successful completion will aid in the technology for combustion of coal in pressurized, fluidized beds. We have now received all the equipment necessary for the flow visualization studies described over the last two progress reports. We have begun more detailed studies of the gas flow pattern within cyclones as detailed below. Third, we have begun studies of the effect of particle concentration on cyclone performance. This work is critical to application of our results to commercial operations. 1 fig.

  14. Tropical cyclone formation

    SciTech Connect

    Montgomery, M.T.; Farrell, B.F. )

    1993-01-15

    The physics of tropical cyclone formation is not well understood, and more is known about the mature hurricane than the formative mechanisms that produce it. It is believed part of the reason for this can be traced to insufficient upper-level atmospheric data. Recent observations suggest that tropical cyclones are initiated by asymmetric interactions associated with migratory upper-level potential vorticity disturbances and low-level disturbances. Favored theories of cyclones formation, however, focus on internal processes associated with cumulus convection and/or air-sea interaction. This work focuses on external mechanisms of cyclone formation and, using both a two- and three-dimensional moist geostrophic momentum model, investigates the role of upper-level potential vorticity disturbances on the formation process. A conceptual model of tropical cyclone formation is proposed, and implications of the theory are discussed. 71 refs., 5 figs., 1 tab.

  15. GAS/LIQUID MEMBRANES FOR NATURAL GAS UPGRADING

    SciTech Connect

    Howard S. Meyer

    2003-07-01

    Gas Technology Institute (GTI) is conducting this research program whose objective is to develop gas/liquid membranes for natural gas upgrading to assist DOE in achieving their goal of developing novel methods of upgrading low quality natural gas to meet pipeline specifications. Kvaerner Process Systems (KPS) and W. L. Gore & Associates (GORE) gas/liquid membrane contactors are based on expanded polytetrafluoroethylene (ePTFE) membranes acting as the contacting barrier between the contaminated gas stream and the absorbing liquid. These resilient membranes provide much greater surface area for transfer than other tower internals, with packing densities five to ten times greater, resulting in equipment 50-70% smaller and lower weight for the same treating service. The scope of the research program is to (1) build and install a laboratory- and a field-scale gas/liquid membrane absorber; (2) operate the units with a low quality natural gas feed stream for sufficient time to verify the simulation model of the contactors and to project membrane life in this severe service; and (3) conducted an economic evaluation, based on the data, to quantify the impact of the technology. Chevron, one of the major producers of natural gas, has offered to host the test at a gas treating plant. KPS will use their position as a recognized leader in the construction of commercial amine plants for building the unit along with GORE providing the membranes. GTI will provide operator and data collection support during lab- and field-testing to assure proper analytical procedures are used. Kvaerner and GTI will perform the final economic evaluation. GTI will provide project management and be responsible for reporting and interactions with DOE on this project. Efforts this quarter have concentrated on field site selection. ChevronTexaco has nominated their Headlee Gas Plant in Odessa, TX for a commercial-scale dehydration test. Design and cost estimation for this new site are underway. Potting

  16. Isothermal gas-liquid flow at reduced gravity

    NASA Technical Reports Server (NTRS)

    Dukler, A. E.

    1990-01-01

    Research on adiabatic gas-liquid flows under reduced gravity condition is presented together with experimental data obtained using a NASA-Lewis RC 100-ft drop tower and in a LeRC Learjet. It is found that flow patterns and characteristics remain unchanged after the first 1.5 s into microgravity conditions and that the calculated time for a continuity wave to traverse the test section is less than 1.2 s. It is also found that the dispersed bubbles move at the same velocity as that of the front of the slug and that the transition between bubbly and slug flow is insensitive to diameter. Both the bubbly and the slug flows are suggested to represent a continuum of the same physical process. The characteristics of annular, slug, and bubbly flows are compared.

  17. Short-Term Outlook for Hydrocarbon Gas Liquids

    EIA Publications

    2016-01-01

    U.S. liquid fuels production increased from 7.43 million barrels per day (b/d) in 2008 to 13.75 million b/d in 2015. However, the Short-Term Energy Outlook (STEO) expects liquid fuels production to decline to 12.99 million b/d in 2017, mainly as a result of prolonged low oil prices. The liquid fuels production forecast reflects a 1.24 million b/d decline in crude oil production by 2017 that is partially offset by a 450,000 b/d increase in the production of hydrocarbon gas liquids (HGL)—a group of products including ethane, propane, butane (normal and isobutane), natural gasoline, and refinery olefins. This analysis will discuss the outlook for each of these four HGL streams and related infrastructure projects through 2017.

  18. Combined Gas-Liquid Plasma Source for Nanoparticle Synthesis

    NASA Astrophysics Data System (ADS)

    Burakov, V. S.; Kiris, V. V.; Nevar, A. A.; Nedelko, M. I.; Tarasenko, N. V.

    2016-09-01

    A gas-liquid plasma source for the synthesis of colloidal nanoparticles by spark erosion of the electrode material was developed and allowed the particle synthesis regime to be varied over a wide range. The source parameters were analyzed in detail for the electrical discharge conditions in water. The temperature, particle concentration, and pressure in the discharge plasma were estimated based on spectroscopic analysis of the plasma. It was found that the plasma parameters did not change signifi cantly if the condenser capacitance was increased from 5 to 20 nF. Purging the electrode gap with argon reduced substantially the pressure and particle concentration. Signifi cant amounts of water decomposition products in addition to electrode elements were found in the plasma in all discharge regimes. This favored the synthesis of oxide nanoparticles.

  19. Gas-liquid chromatographic and gas-liquid-mass spectometric determination of fenvalerate and permethrin residues in grasshoppers and duck tissue samples

    USGS Publications Warehouse

    Reichel, W.L.; Kolbe, E.J.; Stafford, C.J.

    1981-01-01

    A procedure is described for determining fenvalerate and permethrin residues in grasshoppers and duck tissues. Samples are Soxhlet-extracted with hexane and cleaned up by gel permeation chromatography with an in-line alumina column. Samples are analyzed by gas-liquid chromatography with electron capture detection, and confirmed by gas-liquid chromatography-mass spectrometry. The average recovery from fortified tissues was 97%.

  20. Cylindrical Scanner

    SciTech Connect

    Hall, Thomas E.

    1999-04-29

    The CS system is designed to provide a very fast imaging system in order to search for weapons on persons in an airport environment. The Cylindrical Scanner moves a vertical transceiver array rapidly around a person standing stationary. The software can be segmented in to three specific tasks. The first task is data acquisition and scanner control. At the operator's request, this task commands the scanner to move and the radar transceiver array to send data to the computer system in a known and well-ordered manner. The array is moved over the complete aperture in 10 to 12 seconds. At the completion of the array movement the second software task automatically reconstructs the high-resolution image from the radar data utilizing the integrated DSP boards. The third task displays the resulting images, as they become available, to the computer screen for user review and analysis.

  1. Cyclone Chris Hits Australia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This false-color image shows Cyclone Chris shortly after it hit Australia's northwestern coast on February 6, 2002. This scene was acquired by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra satellite. (Please note that this scene has not been reprojected.) Cyclone Chris is one of the most powerful storms ever to hit Australia. Initially, the storm contained wind gusts of up to 200 km per hour (125 mph), but shortly after making landfall it weakened to a Category 4 storm. Meteorologists expect the cyclone to weaken quickly as it moves further inland.

  2. Cyclone performance and optimization

    SciTech Connect

    Leith, D.

    1990-06-15

    The objectives of this project are: to characterize the gas flow pattern within cyclones, to revise the theory for cyclone performance on the basis of these findings, and to design and test cyclones whose dimensions have been optimized using revised performance theory. This work is important because its successful completion will aid in the technology for combustion of coal in pressurized, fluidized beds. During the past quarter, we have nearly completed modeling work that employs the flow field measurements made during the past six months. In addition, we have begun final work using the results of this project to develop improved design methods for cyclones. This work involves optimization using the Iozia-Leith efficiency model and the Dirgo pressure drop model. This work will be completed this summer. 9 figs.

  3. Tropical Cyclone Nargis: 2008

    NASA Video Gallery

    This new animation, developed with the help of NASA's Pleiades supercomputer, illustrates how tropical cyclone Nargis formed in the Indian Ocean's Bay of Bengal over several days in late April 2008...

  4. Evolution of flow disturbances in cocurrent gas-liquid flows

    SciTech Connect

    McCready, M.J.

    1992-10-01

    Studies of interfacial waves in horizontal gas-liquid flows, close to neutral stability, suggest that the rate of evolution of the interface may be linked to nonlinear interactions between the fundamental mode and the subharmonic -- even if the subharmonic is linearly stable. The rate of evolution increases as the subharmonic becomes more unstable. A comparison of linear stability techniques used to predict the initial behavior of waves reveals similar predictions of growth rates and almost identical speeds between a two layer laminar Orr-Sommerfeld theory and an Orr-Sommerfeld theory when the effect of the (turbulent) gas flow enters as boundary conditions on the liquid layer. However, there is disagreement at small wavenumbers as to the point at which the growth curve crosses 0. This is a significant problem because longwave disturbances, in our case roll waves, form by growth of (initially) small amplitude waves that have frequencies which are 0.5 to 1 Hz, which is in the range where the two theories disagree about the sign of the growth rate. While nonlinear effects are probably involved in the formation of the peak (at least while its amplitude is small), the linear growth rate must play an important role when the amplitude is small.

  5. Gas-liquid chromatography of fecal neutral steriods.

    PubMed

    Gerhardt, K O; Gehrke, C W; Rogers, I T; Flynn, M A; Hentges, D J

    1977-05-21

    A method is described for the analysis of fecal neutral steriods with a dual-column gas-liquid chromatography (GLC) system. After saponification of the fecal slurry, the neutral steroids were extracted with hexane. The GLC separation of the compounds and quantitation were achieved by simultaneous injection of the derivatized and derivatized aliquots of the extract onto dual colmuns under identical conditions. The neutral steroids of interest were than identified by matching the retention times with those of known standards, and identification was confirmed by use of an interfaced GLC high-resolution mass spectrometry system. The detection limit was 0.003 mg of steroid/g of fecal slurry. The pricision of the method is illustrated by a relative standard diviation of 2-10% and a recovery of neutral steroids from 73-96%. The method was applied to the determination of fecal neutral steroids in a "High protein diet in colon cancer study". A considerably larger level of coprostanone than of coprostanol was observed. Data on neutral steroids in fecal samples from subjects on different diets are the subject of a separate publication.

  6. Study of interfacial behavior in cocurrent gas-liquid flows

    SciTech Connect

    McCready, M.J.

    1990-01-01

    We have examined the mechanism of formation of solitary waves on gas-liquid flows and found, that these form from existing periodic waves which have sufficiently large ({approximately}1.5 to 2 depending upon fluid properties) amplitude to liquid layer-thickness ratios. The exact process for the wave shape change is not understood but it does not seem to be related to the wave steepness (amplitude/wavelength) or to separation of gas flow over the waves. The observed confinement of solitary waves to low liquid Reynolds numbers results because the necessary large precursor waves do not form if the wave speed dispersion is too large or if the wavelength of the dominant waves is too short, as occurs for higher Re{sub L}. Measurements of interface tracings and calculations of power spectra and bispectra as a function of flow distance for conditions close to neutral stability reveal that the initially, linearly unstable mode is stabilized by formation of overtones which are linearly stable and can dissipate energy. As a result, a stable wave field can occur. Mode equations, which include quadratic nonlinearities, can model this process to the extent of producing some degree of quantitative predictions for the amplitudes of the wave modes. However, a complete picture of the wave field must include sidebands as well because these are observed for some flow conditions. 34 refs., 12 figs., 2 tabs.

  7. Analysis of Developing Gas/liquid Two-Phase Flows

    SciTech Connect

    Elena A. Tselishcheva; Michael Z. Podowski; Steven P. Antal; Donna Post Guillen; Matthias Beyer; Dirk Lucas

    2010-06-01

    The goal of this work is to develop a mechanistically based CFD model that can be used to simulate process equipment operating in the churn-turbulent regime. The simulations were performed using a state-of-the-art computational multiphase fluid dynamics code, NPHASE–CMFD [Antal et al,2000]. A complete four-field model, including the continuous liquid field and three dispersed gas fields representing bubbles of different sizes, was first carefully tested for numerical convergence and accuracy, and then used to reproduce the experimental results from the TOPFLOW test facility at Forschungszentrum Dresden-Rossendorf e.V. Institute of Safety Research [Prasser et al,2007]. Good progress has been made in simulating the churn-turbulent flows and comparison the NPHASE-CMFD simulations with TOPFLOW experimental data. The main objective of the paper is to demonstrate capability to predict the evolution of adiabatic churn-turbulent gas/liquid flows. The proposed modelling concept uses transport equations for the continuous liquid field and for dispersed bubble fields [Tselishcheva et al, 2009]. Along with closure laws based on interaction between bubbles and continuous liquid, the effect of height on air density has been included in the model. The figure below presents the developing flow results of the study, namely total void fraction at different axial locations along the TOPFLOW facility test section. The complete model description, as well as results of simulations and validation will be presented in the full paper.

  8. Gas-liquid interface of room-temperature ionic liquids.

    PubMed

    Santos, Cherry S; Baldelli, Steven

    2010-06-01

    The organization of ions at the interface of ionic liquids and the vacuum is an ideal system to test new ideas and concepts on the interfacial chemistry of electrolyte systems in the limit of no solvent medium. Whilst electrolyte systems have numerous theoretical and experimental methods used to investigate their properties, the ionic liquids are relatively new and our understanding of the interfacial properties is just beginning to be explored. In this critical review, the gas-liquid interface is reviewed, as this interface does not depend on the preparation of another medium and thus produces a natural interface. The interface has been investigated by sum frequency generation vibrational spectroscopy and ultra-high vacuum techniques. The results provide a detailed molecular-level view of the surface composition and structure. These have been complemented by theoretical studies. The combinations of treatments on this interface are starting to provide a somewhat convergent description of how the ions are organized at this neat interface (108 references).

  9. Generation of local concentration gradients by gas-liquid contacting.

    PubMed

    de Jong, Jorrit; Verheijden, Pascal W; Lammertink, Rob G H; Wessling, Matthias

    2008-05-01

    We present a generic concept to create local concentration gradients, based on the absorption of gases or vapors in a liquid. A multilayer microfluidic device with crossing gas and liquid channels is fabricated by micromilling and used to generate multiple gas-liquid contacting regions, separated by a hydrophobic membrane. Each crossing can acts as both a microdosing and microstripping region. Furthermore, the liquid and gas flow rate can be controlled independently of each other. The focus of this conceptual article is on the generation of pH gradients, by locally supplying acidic or basic gases/vapors, such as carbon dioxide, hydrochloric acid, and ammonia, visualized by pH-sensitive dyes. Stationary and moving gradients are presented in devices with 500-microm channel width, depths of 200-400 microm, and lengths of multiple centimeters. It is shown that the method allows for multiple consecutive switching gradients in a single microchannel. Absorption measurements in a microcontactor with the model system CO2/water are presented to indicate the dependence of gas absorption rate on channel depth and residence time. Achievable concentration ranges are ultimately limited by the solubility of used components. The reported devices are easy to fabricate, and their application is not limited to pH gradients. Two proof of principles are demonstrated to indicate new opportunities: (i) local crystallization of NaCl using HCl vapor and (ii) consecutive reactions of ammonia with copper(II) ions in solution.

  10. Gas-Liquid Supersonic Cleaning and Cleaning Verification Spray System

    NASA Technical Reports Server (NTRS)

    Parrish, Lewis M.

    2009-01-01

    NASA Kennedy Space Center (KSC) recently entered into a nonexclusive license agreement with Applied Cryogenic Solutions (ACS), Inc. (Galveston, TX) to commercialize its Gas-Liquid Supersonic Cleaning and Cleaning Verification Spray System technology. This technology, developed by KSC, is a critical component of processes being developed and commercialized by ACS to replace current mechanical and chemical cleaning and descaling methods used by numerous industries. Pilot trials on heat exchanger tubing components have shown that the ACS technology provides for: Superior cleaning in a much shorter period of time. Lower energy and labor requirements for cleaning and de-scaling uper.ninih. Significant reductions in waste volumes by not using water, acidic or basic solutions, organic solvents, or nonvolatile solid abrasives as components in the cleaning process. Improved energy efficiency in post-cleaning heat exchanger operations. The ACS process consists of a spray head containing supersonic converging/diverging nozzles, a source of liquid gas; a novel, proprietary pumping system that permits pumping liquid nitrogen, liquid air, or supercritical carbon dioxide to pressures in the range of 20,000 to 60,000 psi; and various hoses, fittings, valves, and gauges. The size and number of nozzles can be varied so the system can be built in configurations ranging from small hand-held spray heads to large multinozzle cleaners. The system also can be used to verify if a part has been adequately cleaned.

  11. Tropical Cyclone Gonu

    NASA Technical Reports Server (NTRS)

    2007-01-01

    You might expect to see a storm with near-perfect symmetry and a well-defined eye hovering over the warm waters of the Caribbean or in the South Pacific, but Tropical Cyclone Gonu showed up in an unusual place. On June 4, 2007, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite captured this image, Tropical Cyclone Gonu was approaching the northeastern shore of Oman, a region better known for hot desert conditions. Though rare, cyclones like Gonu are not unheard of in the northern Indian Ocean basin. Most cyclones that form in the region form over the Bay of Bengal, east of India. Those that take shape over the Arabian Sea, west of the Indian peninsula, tend to be small and fizzle out before coming ashore. Cyclone Gonu is a rare exception. As of June 4, 2007, the powerful storm had reached a dangerous Category Four status, and it was forecast to graze Oman's northeastern shore, following the Gulf of Oman. According to storm statistics maintained on Unisys Weather, the last storm of this size to form over the Arabian Sea was Cyclone 01A, which tracked northwest along the coast of India between May 21 and May 28, 2001. Unlike Gonu's forecasted track, Cyclone 01A never came ashore. MODIS acquired this photo-like image at 12:00 p.m. local time (9:00 UTC), a few hours after the Joint Typhoon Warning Center estimated Gonu's sustained winds to be over 240 kilometers per hour (145 miles per hour). The satellite image confirms that Gonu was a super-powerful cyclone. The storm has the hallmark tightly wound arms that spiral around a well-defined, circular eye. The eye is surrounded by a clear wall of towering clouds that cast shadows on the surrounding clouds. Called hot towers, these clouds are a sign of the powerful uplift that feeds the storm. The symmetrical spirals, clear eye, and towering clouds are all features regularly seen in satellite images of other particularly powerful cyclones, which are also known as typhoons or hurricanes

  12. Gas-Liquid flow characterization in bubble columns with various gas-liquid using electrical resistance tomography

    NASA Astrophysics Data System (ADS)

    Jin, Haibo; Yuhuan, Han; Suohe, Yang

    2009-02-01

    Electrical resistance tomography (ERT) is an advanced and new detecting technique that can measure and monitor the parameters of two-phase flow on line, such as gas-liquid bubble column. It is fit for the industrial process where the conductible medium serves as the disperse phase to present the key bubble flow characteristics in multi-phase medium. Radial variation of the gas holdup and mean holdups are investigated in a 0.160 m i. d. bubble column using ERT with two axial locations (Plane 1 and Plane 2). In all the experiments, air was used as the gas phase, tap water as liquid phase, and a series of experiments were done by adding KCl, ethanol, oil sodium, and glycerol to change liquid conductivity, liquid surface tension and viscosity. The superficial gas velocity was varied from 0.02 to 0.2 m/s. The effect of conductivity, surface tension, viscosity on the mean holdups and radial gas holdup distribution is discussed. The results showed that the gas holdup decrease with the increase of surface tension and increase with the increase of viscosity. Meanwhile, the settings of initial liquid conductivity slightly influence the gas holdup values, and the experimental data increases with the increase of the initial setting values in the same conditions.

  13. Grey swan tropical cyclones

    NASA Astrophysics Data System (ADS)

    Lin, Ning; Emanuel, Kerry

    2016-01-01

    We define `grey swan’ tropical cyclones as high-impact storms that would not be predicted based on history but may be foreseeable using physical knowledge together with historical data. Here we apply a climatological-hydrodynamic method to estimate grey swan tropical cyclone storm surge threat for three highly vulnerable coastal regions. We identify a potentially large risk in the Persian Gulf, where tropical cyclones have never been recorded, and larger-than-expected threats in Cairns, Australia, and Tampa, Florida. Grey swan tropical cyclones striking Tampa, Cairns and Dubai can generate storm surges of about 6 m, 5.7 m and 4 m, respectively, with estimated annual exceedance probabilities of about 1/10,000. With climate change, these probabilities can increase significantly over the twenty-first century (to 1/3,100-1/1,100 in the middle and 1/2,500-1/700 towards the end of the century for Tampa). Worse grey swan tropical cyclones, inducing surges exceeding 11 m in Tampa and 7 m in Dubai, are also revealed with non-negligible probabilities, especially towards the end of the century.

  14. Drying in cyclones -- A review

    SciTech Connect

    Nebra, S.A.; Silva, M.A.; Mujumdar, A.S.

    2000-03-01

    This paper presents an overview of the flow, heat and mass transfer characteristics of vortex (or cyclone) dryers. The focus is on the potential of the cyclone configuration for drying of particulates. A selective review is made of the literature pertains to single phase and gas-particle flow in cyclone geometries. Recent data on drying of particulates in cyclone dryers are summarized. 56 refs.

  15. Acoustic Probe for Solid-Gas-Liquid Suspension

    SciTech Connect

    Tavlarides, L.L.; Sangani, Ashok

    2003-09-14

    /monitoring two-phase flows in relatively ideal, well-characterized suspensions. Two major factors which we judge has prevented its wide-spread use in the processing industry, particularly for dilute suspensions, is careful selection of the frequency range for interrogation and quantification and removal of the noise introduced by bubbles from the acoustic signal obtained from the suspension. Our research during the first funding period to develop an acoustic probe for solid-gas liquid suspensions has resulted in a theory, supported by our experiments, to describe small amplitude dilute suspensions (Norato, 1999, Spelt et al., 1999, Spelt et al., 2001). The theory agrees well with experimental data of sound attenuation up to 45 {approx}01% suspensions of 0.11 and 77 micron radius polystyrene particles in water and 0.4 to 40 vol %, suspensions of 32 micron soda-lime glass particles in water. Also, analyses of our attenuation experiments for solid-gas liquid experiments suggest the theory can be applied to correct for signal interference due to the presence of bubbles over a selected frequency range to permit determination of the solid-liquid volume fraction. Further, we show experimentally that a reliable linear dependency of weight percent solids with attenuation is obtained for low weight fractions at high frequencies of interrogation where bubble interference is minimal. There was a collaborative effort during the first funding period with the Pacific Northwest National Laboratories in that Dr. Margaret Greenwood was a co-investigator on the project. Dr. Greenwood provided a high level of experimental knowledge and techniques on ultrasound propagation, measurement and data processing. During the second funding period the slurry test loop at Oak Ridge National Laboratories under the direction of Mr. Tom Hylton will be employed to demonstrate the measurement capabilities of the prototype acoustic monitor.

  16. A survey of trace contaminants in natural gas liquids

    SciTech Connect

    Wharry, S.M.; Sung, N.J.

    1995-11-01

    A survey of selected contaminants in natural gas liquids (NGL) has been completed for the purpose of determining whether more stringent NGL specifications should be considered by the industry. The survey involved the analysis of over 45 samples from seven independent processors. The trace contaminants that were analyzed include olefins, oxygenated compounds, fluoride, mercury, and arsenic. Not unsurprisingly, the highest levels of olefins were found in the corresponding hydrocarbon streams, (i.e., propylene in the propane streams). The highest levels of oxygenated compounds were found in the propane and raw make streams. The highest fluoride levels were found in the gasoline samples. And finally, for the most part, the mercury and arsenic levels were to close to the detection limits for these samples ({approximately}10 ppb for mercury and {approximately}50 ppb for arsenic) to be able to accurately determine if these contaminants were present in any of the samples. A more exhaustive study would be needed to analyze for these components below these levels. For the olefins, a gas chromatography procedure was used to determine the levels of pentenes and lighter olefins. For the oxygenated compounds, a water extraction method with a gas chromatography follow up was used. This method measures the levels of all water soluble oxygenated compounds, such as the butanols and lighter alcohols as well as acetone. The fluoride analysis involved the determination of the total fluoride per a modified UOP Method 619-83, the Wickbold method. The mercury and arsenic analyses were obtained by first passing the vapor portion of the samples through appropriate trapping media and then desorbing the traps directly into an inductively coupled plasma-mass spectrometer.

  17. Reuse of spent natural gas liquid sweetening solutions

    SciTech Connect

    Hahn, W.J.; McKim, M.N.; Smith, L.S.

    1995-12-01

    Partially spent caustic solutions from natural gas liquids (NGL) sweetening processes can be used as reagent for sulfur dioxide (SO{sub 2}) scrubbing facilities, reducing the costs for purchasing scrubber reagent and eliminating the costs and liabilities associated with waste disposal. This paper discusses: (1) the characteristics of typical spent NGL sweetening solutions, (2) State and Federal regulations governing the disposal of these solutions as wastes, (3) the operational variables affecting reuse of these solutions in SO{sub 2} scrubbers, (4) field and laboratory analytical data from a pilot project conducted to evaluate the reuse of a partially spent NGL sweetening solution as SO{sub 2} scrubber reagent, and (5) economic data from the pilot project. For the pilot project, a partially spent caustic NGL sweetening solution was used in place of soda ash solution as reagent in a SO{sub 2} scrubber serving two steam generators burning sour gas. Emissions testing of the scrubber demonstrated that the solution provided effective removal of oxides of sulfur (SO{sub x}) in both gaseous and particulate phases to meet permitted limits. Data from the pilot project is used in the paper to: (1) quantify SO{sub 2} scrubber performance with partially spent caustic solutions in terms of SO{sub x} removal efficiency, (2) identify the necessary modifications in scrubber operation (reagent feed rate, scrubber liquor pH and specific gravity, blowdown rate) to achieve acceptable performance using partially spent caustic solutions, and (3) describe the effect that the use of partially spent caustic solutions has on physical and chemical properties of scrubber liquor.

  18. Preparation of pure microbiological samples for pyrolysis gas-liquid chromatography studies

    NASA Technical Reports Server (NTRS)

    Oxborrow, G. S.; Fields, N. D.; Puleo, J. R.

    1976-01-01

    Bacterial samples were prepared for pyrolysis gas-liquid chromatography using cells grown on membrane filters. Pyrochromatograms were reproducible when cells harvested from the filters were pyrolyzed without being washed.

  19. Short-Term Energy Outlook Model Documentation: Hydrocarbon Gas Liquids Supply and Demand

    EIA Publications

    2015-01-01

    The hydrocarbon gas liquids (ethane, propane, butanes, and natural gasoline) module of the Short-Term Energy Outlook (STEO) model is designed to provide forecasts of U.S. production, consumption, refinery inputs, net imports, and inventories.

  20. High performance cyclone development

    SciTech Connect

    Giles, W.B.

    1981-01-01

    The results of cold flow experiments at atmospheric conditions of an air-shielded 18 in-dia electrocyclone with a central cusped electrode are reported using fine test dusts of both flyash and nickel powder. These results are found to confirm expectations of enhanced performance, similar to earlier work on a 12 in-dia model. An analysis of the combined inertial-electrostatic force field is also presented which identifies general design goals and scaling laws. From this, it is found that electrostatic enhancement will be particularly beneficial for fine dusts in large cyclones. Recommendations for further improvement in cyclone collection efficiency are proposed.

  1. Receptivity of a Cryogenic Coaxial Gas-Liquid Jet to Acoustic Disturbances (Briefing Charts)

    DTIC Science & Technology

    2014-03-01

    Gas-Liquid Jet to Acoustic Disturbances 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER Wegener , Forliti, Leyva...of a Cryogenic Coaxial Gas-Liquid Jet to Acoustic Disturbances 50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference Jeff Wegener , UCLA David Forliti...DISTRIBUTION STATEMENT A. Approved for public release; distribution unlimited. Previous injectors (Sophonias, 2012) New injector ( Wegener , 2013) 13Place

  2. Assessing Tropical Cyclone Damage

    NASA Astrophysics Data System (ADS)

    Done, J.; Czajkowski, J.

    2012-12-01

    Landfalling tropical cyclones impact large coastal and inland areas causing direct damage due to winds, storm-surge flooding, tornadoes, and precipitation; as well as causing substantial indirect damage such as electrical outages and business interruption. The likely climate change impact of increased tropical cyclone intensity, combined with increases in exposure, bring the possibility of increased damage in the future. A considerable amount of research has focused on modeling economic damage due to tropical cyclones, and a series of indices have been developed to assess damages under climate change. We highlight a number of ways this research can be improved through a series of case study analyses. First, historical loss estimates are revisited to properly account for; time, impacted regions, the source of damage by type, and whether the damage was direct/indirect and insured/uninsured. Second, the drivers of loss from both the socio-economic and physical side are examined. A case is made to move beyond the use of maximum wind speed to more stable metrics and the use of other characteristics of the wind field such as direction, degree of gustiness, and duration is explored. A novel approach presented here is the potential to model losses directly as a function of climate variables such as sea surface temperature, greenhouse gases, and aerosols. This work is the first stage in the development of a tropical cyclone loss model to enable projections of losses under scenarios of both socio-economic change (such as population migration or altered policy) and physical change (such as shifts in tropical cyclone activity one from basin to another or within the same basin).

  3. DENSE MEDIA CYCLONE OPTIMIZATION

    SciTech Connect

    Gerald H. Luttrell

    2001-09-10

    The fieldwork associated with Task 1 (Baseline Assessment) was completed this quarter. Detailed cyclone inspections completed at all but one plant during maintenance shifts. Analysis of the test samples is also currently underway in Task 4 (Sample Analysis). A Draft Recommendation was prepared for the management at each test site in Task 2 (Circuit Modification). All required procurements were completed. Density tracers were manufactured and tested for quality control purposes. Special sampling tools were also purchased and/or fabricated for each plant site. The preliminary experimental data show that the partitioning performance for all seven HMC circuits was generally good. This was attributed to well-maintained cyclones and good operating practices. However, the density tracers detected that most circuits suffered from poor control of media cutpoint. These problems were attributed to poor x-ray calibration and improper manual density measurements. These conclusions will be validated after the analyses of the composite samples have been completed.

  4. Tropical Cyclone Report, 1986.

    DTIC Science & Technology

    1986-01-01

    following: would be unwarranted at lower risk levels. A rule for deciding such actions can be derived on an expected outcome basis (e.g. cost/ benefits ...responsi- Changes to this year’s publication include: raw bility. fix data files usually printed in Annex A, plus the raw warning, forecast and best...for this report; to the Navy represents data obtained by the tropical cyclone Publications and Printing Service Branch Office, satellite surveillance

  5. Tropical Cyclone Report, 1988

    DTIC Science & Technology

    1988-01-01

    TAIWAN NAVPGSCOL LIBRARY CITIES SERVICES OIL GAS CORP NAVPOLAROCEANCEN SUITLAND CIUDAD UNIVERSITARIA , MEXICO NAVAL RESEARCH LAB CIVIL DEFENSE, SAIPAN...The system software has been provided An effort is now underway to develop a to OAO Corporation for inclusion in the JTWC series of examples...winds in the range of 34 to speed, typically within one degree of the center of a 63 kt (17 to 32 m/sec) inclusive . tropical cyclone. TROPICAL UPPER

  6. Tropical Cyclone Indlala

    NASA Technical Reports Server (NTRS)

    2007-01-01

    On March 14, 2007, storm-weary Madagascar braced for its fourth land-falling tropical cyclone in as many months. Cyclone Indlala was hovering off the island's northeast coast when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite captured this photo-like image at 1:40 p.m. local time (10:40 UTC). Just over a hundred kilometers offshore, the partially cloudy eye at the heart of the storm seems like a vast drain sucking in a disk of swirling clouds. According to reports from the Joint Typhoon Warning Center issued less than three hours after MODIS captured this image, Indlala had winds of 115 knots (132 miles per hour), with gusts up to 140 knots (161 mph). Wave heights were estimated to be 36 feet. At the time of the report, the storm was predicted to intensify through the subsequent 12-hour period, to turn slightly southwest, and to strike eastern Madagascar as a Category 4 storm with sustained winds up to 125 knots (144 mph), and gusts up to 150 knots (173 mph). According to Reuters AlertNet news service, Madagascar's emergency response resources were taxed to their limit in early March 2007 as a result of extensive flooding in the North, drought and food shortages in the South, and three previous hits from cyclones in the preceding few months: Bondo in December 2006, Clovis in January 2007, and Gamede in February.

  7. 1989 Annual Tropical Cyclone Report

    DTIC Science & Technology

    2007-11-02

    z TYPHOON GAY (32W) The fust tropical cyclone of November turned out to be the worst tropical cyclone to affect the Malay Peninsula in 35 years... Gay developed in the Gulf of Thailand, crossed the Malay Peninsula into the Bay of Bengal and slammed into India with peak sustained winds of 140 kt...70 rn/see). Unique because of its small size, intensity, and point of origin, Gay challenged forecasters by crossing two different tropical cyclone

  8. Hybrid double hydrocyclone-gravity gas/liquid separator

    SciTech Connect

    Suh, S.L.; Reeds, C.B.; Van Scherpe, P.; Silcox, W.H.

    1986-10-14

    An apparatus is described for separation of a gas from a liquid in a multiphasic mixture, comprising: an enclosing chamber having a generally cylindrical shape, and an axis through its center; an outlet for allowing gas to leave the enclosing chamber; an outlet for allowing liquid to leave the enclosing chamber; means to control the liquid outflow; a generally smaller chamber within the enclosing chamber, constructed so that a space may be formed between both chambers; the smaller chamber having an inner surface the shape of two cones which are joined at their bases, an inflow line for pressurized well production fluid, the inflow line having an outlet located on the involute inner surface of the smaller chamber where the bases of the cones are joined; a blade means for splitting the flow of production fluid into a stream for each conical section, the blade means being located at the inflow outlet; two liquid outlets for the smaller chamber, the outlets being located at the point of each cone and directed downwards to the bottom of the enclosing chamber; and a gas outlet for the smaller chamber.

  9. Gas-liquid phase separation in oppositely charged colloids: stability and interfacial tension.

    PubMed

    Fortini, Andrea; Hynninen, Antti-Pekka; Dijkstra, Marjolein

    2006-09-07

    We study the phase behavior and the interfacial tension of the screened Coulomb (Yukawa) restricted primitive model (YRPM) of oppositely charged hard spheres with diameter sigma using Monte Carlo simulations. We determine the gas-liquid and gas-solid phase transitions using free energy calculations and grand-canonical Monte Carlo simulations for varying inverse Debye screening length kappa. We find that the gas-liquid phase separation is stable for kappasigmagas-liquid interfacial tension using grand-canonical Monte Carlo simulations. The interfacial tension decreases upon increasing the range of the interaction. In particular, we find that simple scaling can be used to relate the interfacial tension of the YRPM to that of the restricted primitive model, where particles interact with bare Coulomb interactions.

  10. Characterization of annular two-phase gas-liquid flows in microgravity

    NASA Astrophysics Data System (ADS)

    Bousman, W. Scott; McQuillen, John B.

    1994-08-01

    A series of two-phase gas-liquid flow experiments were developed to study annular flows in microgravity using the NASA Lewis Learjet. A test section was built to measure the liquid film thickness around the perimeter of the tube permitting the three dimensional nature of the gas-liquid interface to be observed. A second test section was used to measure the film thickness, pressure drop and wall shear stress in annular microgravity two-phase flows. Three liquids were studied to determine the effects of liquid viscosity and surface tension. The result of this study provide insight into the wave characteristics, pressure drop and droplet entrainment in microgravity annular flows.

  11. A Fixed-Mesh Approach for Gas-Liquid-Rigid Interaction Problems

    NASA Astrophysics Data System (ADS)

    Sugiyama, K.; Okubo, H.; Imahoko, R.; Sakakibara, J.; Takagi, S.

    2016-11-01

    A fixed-mesh approach has been developed to facilitate predicting a certain class of gas-liquid-rigid interaction problems. All the basic equations are discretized on a Cartesian grid in a finite-difference manner. The Volume-Of-Fluid and Boundary Data Immersion methods are employed to treat the gas-liquid and fluid-rigid interfaces, respectively. A hybrid OpenMP- MPI approach is adopted for parallel computing. The developed code is validated through comparisons with experiments of an oil-air flow driven by a rotating disk with holes. The simulated results demonstrate the capability in capturing the velocity distributions.

  12. Characterization of annular two-phase gas-liquid flows in microgravity

    NASA Technical Reports Server (NTRS)

    Bousman, W. Scott; Mcquillen, John B.

    1994-01-01

    A series of two-phase gas-liquid flow experiments were developed to study annular flows in microgravity using the NASA Lewis Learjet. A test section was built to measure the liquid film thickness around the perimeter of the tube permitting the three dimensional nature of the gas-liquid interface to be observed. A second test section was used to measure the film thickness, pressure drop and wall shear stress in annular microgravity two-phase flows. Three liquids were studied to determine the effects of liquid viscosity and surface tension. The result of this study provide insight into the wave characteristics, pressure drop and droplet entrainment in microgravity annular flows.

  13. Cyclone reactor with internal separation and axial recirculation

    DOEpatents

    Becker, F.E.; Smolensky, L.A.

    1988-07-19

    A cyclone combustor apparatus contains a circular partition plate containing a central circular aperture is described. The partition plate divides the apparatus into a cylindrical precombustor chamber and a combustor chamber. A coal-water slurry is passed axially into the inlet end of the precombustor chamber, and primary air is passed tangentially into said chamber to establish a cyclonic air flow. Combustion products pass through the partition plate aperture and into the combustor chamber. Secondary air may also be passed tangentially into the combustor chamber adjacent the partition plate to maintain the cyclonic flow. Flue gas is passed axially out of the combustor chamber at the outlet end and ash is withdrawn tangentially from the combustor chamber at the outlet end. A first mixture of flue gas and ash may be tangentially withdrawn from the combustor chamber at the outlet end and recirculated to the axial inlet of the precombustor chamber with the coal-water slurry. A second mixture may be tangentially withdrawn from the outlet end and passed to a heat exchanger for cooling. Cooled second mixture is then recirculated to the axial inlet of the precombustor chamber. In another embodiment a single cyclone combustor chamber is provided with both the recirculation streams of the first mixture and the second mixture. 10 figs.

  14. Cyclone reactor with internal separation and axial recirculation

    DOEpatents

    Becker, Frederick E.; Smolensky, Leo A.

    1989-01-01

    A cyclone combustor apparatus contains a circular partition plate containing a central circular aperture. The partition plate divides the apparatus into a cylindrical precombustor chamber and a combustor chamber. A coal-water slurry is passed axially into the inlet end of the precombustor chamber, and primary air is passed tangentially into said chamber to establish a cyclonic air flow. Combustion products pass through the partition plate aperture and into the combustor chamber. Secondary air may also be passed tangentially into the combustor chamber adjacent the partition plate to maintain the cyclonic flow. Flue gas is passed axially out of the combustor chamber at the outlet end and ash is withdrawn tangentially from the combuston chamber at the outlet end. A first mixture of flue gas and ash may be tangentially withdrawn from the combustor chamber at the outlet end and recirculated to the axial inlet of the precombustor chamber with the coal-water slurry. A second mixture of flue gas and ash may be tangentially withdrawn from the outlet end of the combustor chamber and passed to a heat exchanger for cooling. Cooled second mixture is then recirculated to the axial inlet of the precombustor chamber. In another embodiment a single cyclone combustor chamber is provided with both the recirculation streams of the first mixture and the second mixture.

  15. Conceptual Models of Frontal Cyclones.

    ERIC Educational Resources Information Center

    Eagleman, Joe R.

    1981-01-01

    This discussion of weather models uses maps to illustrate the differences among three types of frontal cyclones (long wave, short wave, and troughs). Awareness of these cyclones can provide clues to atmospheric conditions which can lead toward accurate weather forecasting. (AM)

  16. Advances in dust cyclone research

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dust cyclones reduce particulate emissions but their operation consumes electrical energy. Response surface methodology was used to compare two strategies to reduce energy costs without increasing emissions. Cyclones of a standard design (1D3D) were operated singly and in series, as was an ‘Experi...

  17. Atlantic tropical cyclones revisited

    NASA Astrophysics Data System (ADS)

    Mann, Michael E.; Emanuel, Kerry A.; Holland, Greg J.; Webster, Peter J.

    Vigorous discussions have taken place recently in Eos [e.g., Mann and Emanuel, 2006; Landsea, 2007] and elsewhere [Emanuel, 2005; Webster et al., 2005; Hoyos et al., 2006; Trenberth and Shea, 2006; Kossin et al., 2007] regarding trends in North Atlantic tropical cyclone (TC) activity and their potential connection with anthropogenic climate change. In one study, for example [Landsea, 2007], it is argued that a substantial underestimate of Atlantic tropical cyclone counts in earlier decades arising from insufficient observing systems invalidates the conclusion that trends in TC behavior may be connected to climate change. Here we argue that such connections are in fact robust with respect to uncertainties in earlier observations.Several recent studies have investigated trends in various measures of TC activity. Emanuel [2005] showed that a measure of total power dissipation by TCs (the power dissipation index, or PDI) is highly correlated with August-October sea surface temperatures (SST) over the main development region (MDR) for Atlantic TCs over at least the past half century. Some support for this conclusion was provided by Sriver and Ruber [2006]. Webster et al. [2005] demonstrated a statistically significant increase in recent decades in both the total number of the strongest category cyclones (categories 4 and 5) and the proportion of storms reaching hurricane intensity. Hoyos et al. [2006] showed that these increases were closely tied to warming trends in tropical Atlantic SST, while, for example, the modest decrease in vertical wind shear played a more secondary role. Kossin et al. [2007] called into question some trends in other basins, based on a reanalysis of past TC data, but they found the North Atlantic trends to be robust.

  18. DENSE MEDIA CYCLONE OPTIMIZATION

    SciTech Connect

    Gerald H. Luttrell

    2002-09-14

    All project activities are now winding down. Follow-up tracer tests were conducted at several of the industrial test sites and analysis of the experimental data is currently underway. All required field work was completed during this quarter. In addition, the heavy medium cyclone simulation and expert system programs are nearly completed and user manuals are being prepared. Administrative activities (e.g., project documents, cost-sharing accounts, etc.) are being reviewed and prepared for final submission to DOE. All project reporting requirements are up to date. All financial expenditures are within approved limits.

  19. The Separation and Identification of Straight Chain Hydrocarbons: An Experiment Using Gas-Liquid Chromatography.

    ERIC Educational Resources Information Center

    Benson, G. A.

    1982-01-01

    An experiment using gas-liquid chromatography is discussed, introducing the student to concept of dead volume and its measurement, idea and use of an internal reference compound, and to linear relationship existing between measurements of a separation on two different stationary phases. (Author/SK)

  20. Properties of hydrophobic free energy found by gas-liquid transfer.

    PubMed

    Baldwin, Robert L

    2013-01-29

    The hydrophobic free energy in current use is based on transfer of alkane solutes from liquid alkanes to water, and it has been argued recently that these values are incorrect and should be based instead on gas-liquid transfer data. Hydrophobic free energy is measured here by gas-liquid transfer of hydrocarbon gases from vapor to water. The new definition reduces more than twofold the values of the apparent hydrophobic free energy. Nevertheless, the newly defined hydrophobic free energy is still the dominant factor that drives protein folding as judged by ΔCp, the change in heat capacity, found from the free energy change for heat-induced protein unfolding. The ΔCp for protein unfolding agrees with ΔCp values for solvating hydrocarbon gases and disagrees with ΔCp for breaking peptide hydrogen bonds, which has the opposite sign. The ΔCp values for the enthalpy of liquid-liquid and gas-liquid transfer are similar. The plot of free energy against the apparent solvent-exposed surface area is given for linear alkanes, but only for a single conformation, the extended conformation, of these flexible-chain molecules. The ability of the gas-liquid hydrophobic factor to predict protein stability is tested and reasonable agreement is found, using published data for the dependences on temperature of the unfolding enthalpy of ribonuclease T1 and the solvation enthalpies of the nonpolar and polar groups.

  1. Gas/liquid sensing via chemotaxis of Euglena cells confined in an isolated micro-aquarium.

    PubMed

    Ozasa, Kazunari; Lee, Jeesoo; Song, Simon; Hara, Masahiko; Maeda, Mizuo

    2013-10-21

    We demonstrate on-chip gas/liquid sensing by using the chemotaxis of live bacteria (Euglena gracilis) confined in an isolated micro-aquarium, and gas/liquid permeation through porous polydimethylsiloxane (PDMS). The sensing chip consisted of one closed micro-aquarium and two separated bypass microchannels along the perimeter of the micro-aquarium. Test gas/liquid and reference samples were introduced into the two individual microchannels separately, and the gas/liquid permeated through the PDMS walls and dissolved in the micro-aquarium water, resulting in a chemical concentration gradient in the micro-aquarium. By employing the closed micro-aquarium isolated from sample flows, we succeeded in measuring the chemotaxis of Euglena for a gas substance quantitatively, which cannot be achieved with the conventional flow-type or hydro-gel-type microfluidic devices. We found positive (negative) chemotaxis for CO2 concentrations below (above) 15%, with 64 ppm as the minimum concentration affecting the cells. We also observed chemotaxis for ethanol and H2O2. By supplying culture medium via the microchannels, the Euglena culture remained alive for more than 2 months. The sensing chip is thus useful for culturing cells and using them for environmental toxicity/nutrition studies by monitoring their motion.

  2. Appropriate Formulations for Velocity and Pressure Calculations at Gas-liquid Interface with Collocated Variable Arrangement

    NASA Astrophysics Data System (ADS)

    Ito, Kei; Kunugi, Tomoaki

    A high-precision simulation algorithm for gas-liquid two-phase flows on unstructured meshes has been developed to simulate gas entrainment phenomenon in a sodium-cooled fast reactor. In this study, it became clear that unphysical behaviors near gas-liquid interfaces were caused by conventional algorithms. Then, physics-basis considerations were conducted for mechanical balances at gas-liquid interfaces to derive appropriate formulations. By defining momentum and velocity independently and developing the momentum transport equations for both gas and liquid phases, the physically appropriate formulation of momentum transport was derived, which eliminated the unphysical pressure distribution caused by the conventional formulation. In addition, the physically appropriate formulation was derived for the pressure gradient to satisfy the mechanical balances between pressure and surface tension at gas-liquid interfaces. As the validation test, the rising gas bubble in liquid was simulated by the developed simulation algorithm with the physically appropriate formulations, and the simulated terminal bubble shapes on the structured and highly-distorted unstructured meshes coincided with the experimental data under each simulation condition determined by the Morton and Eötvös numbers.

  3. Multi-scale symbolic time reverse analysis of gas-liquid two-phase flow structures

    NASA Astrophysics Data System (ADS)

    Wang, Hongmei; Zhai, Lusheng; Jin, Ningde; Wang, Youchen

    Gas-liquid two-phase flows are widely encountered in production processes of petroleum and chemical industry. Understanding the dynamic characteristics of multi-scale gas-liquid two-phase flow structures is of great significance for the optimization of production process and the measurement of flow parameters. In this paper, we propose a method of multi-scale symbolic time reverse (MSTR) analysis for gas-liquid two-phase flows. First, through extracting four time reverse asymmetry measures (TRAMs), i.e. Euclidean distance, difference entropy, percentage of constant words and percentage of reversible words, the time reverse asymmetry (TRA) behaviors of typical nonlinear systems are investigated from the perspective of multi-scale analysis, and the results show that the TRAMs are sensitive to the changing of dynamic characteristics underlying the complex nonlinear systems. Then, the MSTR analysis is used to study the conductance signals from gas-liquid two-phase flows. It is found that the multi-scale TRA analysis can effectively reveal the multi-scale structure characteristics and nonlinear evolution properties of the flow structures.

  4. Tropical Cyclone Information System

    NASA Technical Reports Server (NTRS)

    Li, P. Peggy; Knosp, Brian W.; Vu, Quoc A.; Yi, Chao; Hristova-Veleva, Svetla M.

    2009-01-01

    The JPL Tropical Cyclone Infor ma tion System (TCIS) is a Web portal (http://tropicalcyclone.jpl.nasa.gov) that provides researchers with an extensive set of observed hurricane parameters together with large-scale and convection resolving model outputs. It provides a comprehensive set of high-resolution satellite (see figure), airborne, and in-situ observations in both image and data formats. Large-scale datasets depict the surrounding environmental parameters such as SST (Sea Surface Temperature) and aerosol loading. Model outputs and analysis tools are provided to evaluate model performance and compare observations from different platforms. The system pertains to the thermodynamic and microphysical structure of the storm, the air-sea interaction processes, and the larger-scale environment as depicted by ocean heat content and the aerosol loading of the environment. Currently, the TCIS is populated with satellite observations of all tropical cyclones observed globally during 2005. There is a plan to extend the database both forward in time till present as well as backward to 1998. The portal is powered by a MySQL database and an Apache/Tomcat Web server on a Linux system. The interactive graphic user interface is provided by Google Map.

  5. An Observational Analysis of Tropical Cyclone Recurvature.

    DTIC Science & Technology

    1991-05-01

    SR = Slowly recurving cyclones TC = Tropical Cyclone TUTT = Tropical Upper Tropospheric Trough W = West WNW = West-Northwest v Chapter 1 INTRODUCTION...latitude at which the cyclone was located. Observations also showed that not all troughs approaching a cyclone caused recurvature. Mid- latitude troughs ...general synoptic conditions which were favorable for tropical cyclone recurvature. These included: 1. High amplitude troughs extending from the westerlies

  6. Monitoring by Control Technique - Cyclone

    EPA Pesticide Factsheets

    Stationary source emissions monitoring is required to demonstrate that a source is meeting the requirements in Federal or state rules. This page is about cyclone control techniques used to reduce pollutant emissions.

  7. Tropical Cyclone Bejisa Near Madagascar

    NASA Video Gallery

    NASA's TRMM satellite flew over Cyclone Bejisa on December 29, 2013 at 1507 UTC. This 3-D animation of TRMM data revealed strong thunderstorms around Bejisa's center were reaching heights above 16....

  8. Study on measures to improve gas-liquid phase mixing in a multiphase pump impeller under high gas void fraction

    NASA Astrophysics Data System (ADS)

    Zhang, J. Y.; Zhu, H. W.; Ding, K.; Qiang, R.

    2012-11-01

    Rotodynamic multiphase pump can transport crude gas-liquid mixture produced from oil well, and is regarded as the good choice of oil-gas multiphase transportation in offshore product system, for its advantages that compact structure, large flow rate, not sensitive to solid particles in the fluid. However, it is prone to bring about gas-liquid separation within the impeller under high gas void fraction. To solve the problem, this paper presents several measures to break gas packet and inhibit gas-liquid separation, such as, depositing the short blades, opening holes at the blades where gas packets gather, using T-shaped blades, etc. Then, CFD software was used to simulate the flow fields which were added measures to inhibit gas-liquid separation. The results show that streamlines in three new impellers distribute more evenly than in original impeller, the gas-liquid two phases mixed degree was improved, and the gas-liquid separation was inhibited to some extent. However, adding the short blades and using T-blade impeller failed to improve the differential pressure of impellers. So the placement and the geometrical parameters of the measures inhibiting gas-liquid separation should be further optimized.

  9. Annual Tropical Cyclone Report 2010

    DTIC Science & Technology

    2010-01-01

    period of rapid intensification. Tropical Cyclone 04B matured as a relatively small cyclone, its upper-level cirrus cloud shield spanning... defined cirrus outflow streak poleward of the low-level circulation center around 22/00Z. These structural changes are evident in the satellite imagery...erratically based on the upper level cloud patterns and convective maxima. It was not until visible imagery became available, that the two low level

  10. Cylindrical neutron generator

    DOEpatents

    Leung, Ka-Ngo

    2005-06-14

    A cylindrical neutron generator is formed with a coaxial RF-driven plasma ion source and target. A deuterium (or deuterium and tritium) plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical neutron generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which contain many slots. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired. The plasma generator may be in the center and the neutron target on the outside, or the plasma generator may be on the outside and the target on the inside. In a nested configuration, several concentric targets and plasma generating regions are nested to increase the neutron flux.

  11. Cylindrical neutron generator

    DOEpatents

    Leung, Ka-Ngo

    2009-12-29

    A cylindrical neutron generator is formed with a coaxial RF-driven plasma ion source and target. A deuterium (or deuterium and tritium) plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical neutron generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which contain many slots. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired. The plasma generator may be in the center and the neutron target on the outside, or the plasma generator may be on the outside and the target on the inside. In a nested configuration, several concentric targets and plasma generating regions are nested to increase the neutron flux.

  12. Cylindrical neutron generator

    DOEpatents

    Leung, Ka-Ngo

    2008-04-22

    A cylindrical neutron generator is formed with a coaxial RF-driven plasma ion source and target. A deuterium (or deuterium and tritium) plasma is produced by RF excitation in a cylindrical plasma ion generator using an RF antenna. A cylindrical neutron generating target is coaxial with the ion generator, separated by plasma and extraction electrodes which contain many slots. The plasma generator emanates ions radially over 360.degree. and the cylindrical target is thus irradiated by ions over its entire circumference. The plasma generator and target may be as long as desired. The plasma generator may be in the center and the neutron target on the outside, or the plasma generator may be on the outside and the target on the inside. In a nested configuration, several concentric targets and plasma generating regions are nested to increase the neutron flux.

  13. Gas-liquid chromatography in routine processing of blood cultures for detecting anaerobic bacteraemia.

    PubMed Central

    Reig, M; Molina, D; Loza, E; Ledesma, M A; Meseguer, M A

    1981-01-01

    Gas-liquid chromatography was performed on 233 positive blood cultures and findings were compared with culture results. Obligate anaerobic bacteria were recovered from 78 out of 79 blood cultures containing butyric or iso-valeric acids, or both; from 28 out of 69 blood cultures containing succinic acid; and from only one out of 41 blood cultures containing succinic but not butyric or iso-valeric acid. Good correlations (88%) were found for the recovery of anaerobic bacteria and the detection of butyric and/or iso-valeric acids. Detecting volatile fatty acids by gas-liquid chromatography performed on blood cultures at the first signs of growth can therefore provide an early and reliable indication of the presence of anaerobic bacteria. PMID:7014645

  14. Hollow fiber gas-liquid membrane contactors for acid gas capture: a review.

    PubMed

    Mansourizadeh, A; Ismail, A F

    2009-11-15

    Membrane contactors using microporous membranes for acid gas removal have been extensively reviewed and discussed. The microporous membrane acts as a fixed interface between the gas and the liquid phase without dispersing one phase into another that offers a flexible modular and energy efficient device. The gas absorption process can offer a high selectivity and a high driving force for transport even at low concentrations. Using hollow fiber gas-liquid membrane contactors is a promising alternative to conventional gas absorption systems for acid gas capture from gas streams. Important aspects of membrane contactor as an efficient energy devise for acid gas removal including liquid absorbents, membrane characteristics, combination of membrane and absorbent, mass transfer, membrane modules, model development, advantages and disadvantages were critically discussed. In addition, current status and future potential in research and development of gas-liquid membrane contactors for acid gas removal were also briefly discussed.

  15. Measurements of interfacial dynamics of gas-liquid displacement in a capillary

    NASA Astrophysics Data System (ADS)

    Yan, Changfei; Qiu, Huihe

    2016-06-01

    Measurement of liquid film thickness in gas-liquid plug/slug flows is a challenging task. A novel laser interference method for measuring the interfacial film thickness of gas-liquid displacement in a plug flow has been developed. This novel technique utilizes light scattering from different liquid/gas interfaces in forming interference fringes. The interference fringes are used for calculating the film thickness. A set of simultaneous equations is derived based on geometrical optics. The experiment set up is not complex and is easy to install. The fringes are recorded by a charge-coupled device high speed camera and the image data are calculated using fast Fourier transform (FFT) and a non-linear least squares Levenberg-Marquardt algorithm. The uncertainty of this measurement technique is quite small (0.3 μm) and the entire film thickness profile can be measured at the same time.

  16. Investigation Of The High-Voltage Discharge On The Surface Of Gas-Liquid System

    NASA Astrophysics Data System (ADS)

    Nguyen-Kuok, Shi; Morgunov, Aleksandr; Malakhov, Yury; Korotkikh, Ivan

    2016-09-01

    This paper describes an experimental setup for study of physical processes in the high-voltage discharge on the surface of gas-liquid system at atmospheric pressure. Measurements of electrical and optical characteristics of the high-voltage discharge in gas, at the surface of the gas-liquid system and in the electrolyte are obtained. The parameters of the high-voltage discharge and the conditions for its stable operation are presented. Investigations with various electrolytes and cathode assemblies of various materials and sizes were carried out. The installation can be used for the processing and recycling of industrial and chemical liquid waste. Professor of Laboratory of Plasma Physics, National Research University MPEI, Krasnokazarmennya Str.14, 111250, Moscow, Russia.

  17. DEVELOPMENT AND VALIDATION OF A MULTIFIELD MODEL OF CHURN-TURBULENT GAS/LIQUID FLOWS

    SciTech Connect

    Elena A. Tselishcheva; Steven P. Antal; Michael Z. Podowski; Donna Post Guillen

    2009-07-01

    The accuracy of numerical predictions for gas/liquid two-phase flows using Computational Multiphase Fluid Dynamics (CMFD) methods strongly depends on the formulation of models governing the interaction between the continuous liquid field and bubbles of different sizes. The purpose of this paper is to develop, test and validate a multifield model of adiabatic gas/liquid flows at intermediate gas concentrations (e.g., churn-turbulent flow regime), in which multiple-size bubbles are divided into a specified number of groups, each representing a prescribed range of sizes. The proposed modeling concept uses transport equations for the continuous liquid field and for each bubble field. The overall model has been implemented in the NPHASE-CMFD computer code. The results of NPHASE-CMFD simulations have been validated against the experimental data from the TOPFLOW test facility. Also, a parametric analysis on the effect of various modeling assumptions has been performed.

  18. U.S. crude oil, natural gas, and natural gas liquids reserves 1997 annual report

    SciTech Connect

    Wood, John H.; Grape, Steven G.; Green, Rhonda S.

    1998-12-01

    This report presents estimates of proved reserves of crude oil, natural gas, and natural gas liquids as of December 31, 1997, as well as production volumes for the US and selected States and State subdivisions for the year 1997. Estimates are presented for the following four categories of natural gas: total gas (wet after lease separation), nonassociated gas and associated-dissolved gas (which are the two major types of wet natural gas), and total dry gas (wet gas adjusted for the removal of liquids at natural gas processing plants). In addition, reserve estimates for two types of natural gas liquids, lease condensate and natural gas plant liquids, are presented. Also included is information on indicated additional crude oil reserves and crude oil, natural gas, and lease condensate reserves in nonproducing reservoirs. A discussion of notable oil and gas exploration and development activities during 1997 is provided. 21 figs., 16 tabs.

  19. US crude oil, natural gas, and natural gas liquids reserves, 1992 annual report

    SciTech Connect

    Not Available

    1993-10-18

    This report presents estimates of proved reserves of crude oil, natural gas, and natural gas liquids as of December 31, 1992, as well as production volumes for the United States, and selected States and State subdivisions for the year 1992. Estimates are presented for the following four categories of natural gas: total gas (wet after lease separation), its two major components (nonassociated and associated-dissolved gas), and total dry gas (wet gas adjusted for the removal of liquids at natural gas processing plants). In addition, two components of natural gas liquids, lease condensate and natural gas plant liquids, have their reserves and production data presented. Also included is information on indicated additional crude oil reserves and crude oil, natural gas, and lease condensate reserves in nonproducing reservoirs. A discussion of notable oil and gas exploration and development activities during 1992 is provided.

  20. Pyrolysis gas-liquid chromatography of the genus Bacillus: effect of growth media on pyrochromatogram reproducibility.

    PubMed

    Oxborrow, G S; Fields, N D; Puleo, J R

    1977-04-01

    Pyrolysis gas-liquid chromatography was performed on dried Bacillus microorganisms to evaluate the effects of growth media. Six cultures of Bacillus and six lot numbers of Trypticase soy agar (BBL) were used to test the hypothesis that a microorganism grown on various lot numbers of the same chromatogram. Also tested was the effect of three different media on chromatogram reproduction using the same six cultures. Results show little or no differences observed between the chromatograms of the individual Bacillus spp. grown on the six lot numbers of Trypticase soy agar. When chromatograms of the three different media were compared, several differences were observed, particularly in the areas most characteristic of individual species. Pryolysis gas-liquid chromatography can be a useful tool for the characterization or identification of the genus Bacillus if the chromatographic and cultural conditions are maintained.

  1. Static gas-liquid interfacial direct current discharge plasmas using ionic liquid cathode

    SciTech Connect

    Kaneko, T.

    2009-05-15

    Due to the unique properties of ionic liquids such as their extremely low vapor pressure and high heat capacity, we have succeeded in creating the static and stable gas (plasmas)-liquid (ionic liquids) interfacial field using a direct current discharge under a low gas pressure condition. It is clarified that the ionic liquid works as a nonmetal liquid electrode, and furthermore, a secondary electron emission coefficient of the ionic liquid is larger than that of conventional metal electrodes. The plasma potential structure of the gas-liquid interfacial region, and resultant interactions between the plasma and the ionic liquid are revealed by changing a polarity of the electrode in the ionic liquid. By utilizing the ionic liquid as a cathode electrode, the positive ions in the plasma region are found to be irradiated to the ionic liquid. This ion irradiation causes physical and chemical reactions at the gas-liquid interfacial region without the vaporization of the ionic liquid.

  2. Cylindrically symmetric wormholes

    SciTech Connect

    Kuhfittig, Peter K.F.

    2005-05-15

    This paper discusses traversable wormholes that differ slightly but significantly from those of the Morris-Thorne type under the assumption of cylindrical symmetry. The throat is a piecewise smooth cylindrical surface resulting in a shape function that is not differentiable at some value. It is proposed that the regular derivative be replaced by a one-sided derivative at this value. The resulting wormhole geometry satisfies the weak energy condition.

  3. Acoustic probe for solid-gas-liquid suspensions. 1998 annual progress report

    SciTech Connect

    Tavlarides, L.L.; Sangani, A.S.; Greenwood, M.S.

    1998-06-01

    'The proposed research will develop an acoustic probe for monitoring particle size and volume fraction in slurries in the absence and presence of gas. The goals are to commission and verify the probe components and system operation, develop theory for the forward and inverse problems for acoustic wave propagation through a three phase medium, and experimentally verify the theoretical analysis. The acoustic probe will permit measurement of solid content in gas-liquid-solid waste slurries in tanks across the DOE complex.'

  4. Black Swan Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Emanuel, K.; Lin, N.

    2012-12-01

    Virtually all assessments of tropical cyclone risk are based on historical records, which are limited to a few hundred years at most. Yet stronger TCs may occur in the future and at places that have not been affected historically. Such events lie outside the realm of historically based expectations and may have extreme impacts. Their occurrences are also often made explainable after the fact (e.g., Hurricane Katrina). We nickname such potential future TCs, characterized by rarity, extreme impact, and retrospective predictability, "black swans" (Nassim Nicholas Taleb, 2007). As, by definition, black swan TCs have yet to happen, statistical methods that solely rely on historical track data cannot predict their occurrence. Global climate models lack the capability to predict intense storms, even with a resolution as high as 14 km (Emanuel et al. 2010). Also, most dynamic downscaling methods (e.g., Bender et al. 2010) are still limited in horizontal resolution and are too expensive to implement to generate enough events to include rare ones. In this study, we apply a simpler statistical/deterministic hurricane model (Emanuel et al. 2006) to simulate large numbers of synthetic storms under a given (observed or projected) climate condition. The method has been shown to generate realistic extremes in various basins (Emanuel et al. 2008 and 2010). We also apply a hydrodynamic model (ADCIRC; Luettich et al. 1992) to simulate the storm surges generated by these storms. We then search for black swan TCs, in terms of the joint wind and surge damage potential, in the generated large databases. Heavy rainfall is another important TC hazard and will be considered in a future study. We focus on three areas: Tampa Bay in the U.S., the Persian Gulf, and Darwin in Australia. Tampa Bay is highly vulnerable to storm surge as it is surrounded by shallow water and low-lying lands, much of which may be inundated by a storm tide of 6 m. High surges are generated by storms with a broad

  5. Degradation of Microcystin-LR by Gas-Liquid Interfacial Discharge Plasma

    NASA Astrophysics Data System (ADS)

    Xin, Qing; Zhang, Yi; Wu, Kaibin

    2013-12-01

    In this study, we report on the degradation of microcystin-LR (MC-LR) by gas-liquid interfacial discharge plasma. The influences of operation parameters such as average input voltage, electrode distance and gas flow rate are investigated. Experimental results indicate that the input voltage and gas flow rate have positive influences on MC-LR degradation, while the electrode distance has a negative one. After 6 min discharge with 25 kV average input voltage and 60 L/h air aeration, the degradation rate of MC-LR achieves 75.3%. H2O2 and O3 generated by discharge both in distilled water and MC-LR solution are measured. Moreover, an emission spectroscopy is used as an indicator of the processes that take place on the gas-liquid boundary and inside plasma. Varied types of radicals (O, ·OH, CO, O3, etc.) are proved to be present in the gas phase during gas-liquid interfacial discharge.

  6. U.S. crude oil, natural gas, and natural gas liquids reserves 1995 annual report

    SciTech Connect

    1996-11-01

    The EIA annual reserves report series is the only source of comprehensive domestic proved reserves estimates. This publication is used by the Congress, Federal and State agencies, industry, and other interested parties to obtain accurate estimates of the Nation`s proved reserves of crude oil, natural gas, and natural gas liquids. These data are essential to the development, implementation, and evaluation of energy policy and legislation. This report presents estimates of proved reserves of crude oil, natural gas, and natural gas liquids as of December 31, 1995, as well as production volumes for the US and selected States and State subdivisions for the year 1995. Estimates are presented for the following four categories of natural gas: total gas (wet after lease separation), nonassociated gas and associated-dissolved gas (which are the two major types of wet natural gas), and total dry gas (wet gas adjusted for the removal of liquids at natural gas processing plants). In addition, reserve estimates for two types of natural gas liquids, lease condensate and natural gas plant liquids, are presented. Also included is information on indicated additional crude oil reserves and crude oil, natural gas, and lease condensate reserves in nonproducing reservoirs. A discussion of notable oil and gas exploration and development activities during 1995 is provided. 21 figs., 16 tabs.

  7. US crude oil, natural gas, and natural gas liquids reserves 1996 annual report

    SciTech Connect

    1997-12-01

    The EIA annual reserves report series is the only source of comprehensive domestic proved reserves estimates. This publication is used by the Congress, Federal and State agencies, industry, and other interested parties to obtain accurate estimates of the Nation`s proved reserves of crude oil, natural gas, and natural gas liquids. These data are essential to the development, implementation, and evaluation of energy policy and legislation. This report presents estimates of proved reserves of crude oil, natural gas, and natural gas liquids as of December 31, 1996, as well as production volumes for the US and selected States and State subdivisions for the year 1996. Estimates are presented for the following four categories of natural gas: total gas (wet after lease separation), nonassociated gas and associated-dissolved gas (which are the two major types of wet natural gas), and total dry gas (wet gas adjusted for the removal of liquids at natural gas processing plants). In addition, reserve estimates for two types of natural gas liquids, lease condensate and natural gas plant liquids, are presented. Also included is information on indicated additional crude oil reserves and crude oil, natural gas, and lease condensate reserves in nonproducing reservoirs. A discussion of notable oil and gas exploration and development activities during 1996 is provided. 21 figs., 16 tabs.

  8. Ultrasound in gas-liquid systems: effects on solubility and mass transfer.

    PubMed

    Laugier, F; Andriantsiferana, C; Wilhelm, A M; Delmas, H

    2008-09-01

    The effect of ultrasound on the pseudo-solubility of nitrogen in water and on gas-liquid mass transfer kinetics has been investigated in an autoclave reactor equipped with a gas induced impeller. In order to use organic liquids and to investigate the effect of pressure, gas-liquid mass transfer coefficient was calculated from the evolution of autoclave pressure during gas absorption to avoid any side-effects of ultrasound on the concentrations measurements. Ultrasound effect on the apparent solubility is very low (below 12%). Conversely ultrasound greatly improves gas-liquid mass transfer, especially below gas induction speed, this improvement being boosted by pressure. In typical conditions of organic synthesis: 323 K, 1100 rpm, 10 bar, k(L).a is multiplied by 11 with ultrasound (20 kHz/62.6 W). The impact of sonication is much higher on gassing out than on gassing in. In the same conditions, this enhancement is at least five times higher for degassing.

  9. Gas-liquid phase coexistence and crossover behavior of binary ionic fluids with screened Coulomb interactions.

    PubMed

    Patsahan, O

    2014-06-01

    We study the effects of an interaction range on the gas-liquid phase diagram and the crossover behavior of a simple model of ionic fluids: an equimolar binary mixture of equisized hard spheres interacting through screened Coulomb potentials which are repulsive between particles of the same species and attractive between particles of different species. Using the collective variables theory, we find explicit expressions for the relevant coefficients of the effective φ{4} Ginzburg-Landau Hamiltonian in a one-loop approximation. Within the framework of this approximation, we calculate the critical parameters and gas-liquid phase diagrams for varying inverse screening length z. Both the critical temperature scaled by the Yukawa potential contact value and the critical density rapidly decrease with an increase of the interaction range (a decrease of z) and then for z<0.05 they slowly approach the values found for a restricted primitive model (RPM). We find that gas-liquid coexistence region reduces with an increase of z and completely vanishes at z≃2.78. Our results clearly show that an increase in the interaction range leads to a decrease of the crossover temperature. For z≃0.01, the crossover temperature is the same as for the RPM.

  10. Investigation on a gas-liquid ejector using three-dimensional CFD model

    NASA Astrophysics Data System (ADS)

    Kang, S. H.; Song, X. G.; Park, Y. C.

    2012-11-01

    This paper is focusing on the numeral study of a gas-liquid ejector used for ballast water treatment. The gasliquid ejector is investigated through steady three-dimensional multiphase CFD analysis with commercial software ANSYS-CFX 13.0. Water as the primary fluid is driven through the driving nozzle and air is ejected into as the second gas instead of the ozone in real application. Several turbulence models such as Standard k-ɛ model, RNG k-ɛ model, SST model and k-ω model, and different mesh size and compared extensively with the experimental results to eliminate the influence of the auxiliary system, turbulence models and mesh generation. The appropriate numerical model in terms of the best combination of turbulence model and mesh size are used in the subsequent research the study the influence of the operating condition such as the driving pressure/velocity and the back pressure of the ejector on its performance. The results provide deep insight on the influence of various factors on the performance of gas-liquid ejector. And the proposed numerical model will be very helpful in the further design optimization of the gas-liquid ejectors.

  11. Calculations of Gas-liquid Equilibrium in Wellbore with High Carbon dioxide Flow

    NASA Astrophysics Data System (ADS)

    Zhang, Jiaming; Wu, Xiaodong; Wang, Bo; Liu, Kai; Gao, Yue

    2014-05-01

    Carbon dioxide injection not only enhances the oil recovery dramatically, but also it will reduce the greenhouse effect, therefore, Carbon dioxide injection technique is applied extensively. During the process of carbon dioxide displacement, when carbon dioxide breaks though into oil production wells, carbon dioxide content will impacts the phase state and physical properties of the mixed liquor in the wellbore, as a result, it will affect the calculation of temperature and pressure in oil production wells. Applying the conventional black-oil model to calculate the phase state of the miscible fluids is unacceptable. To tackle the problem, this paper uses the gas-liquid flash theory and component model to program software, so that the phase state (gas, liquid or gas-liquid) and physical properties of the mixed liquor (including hydrogen sulfide, carbon dioxide and hydrocarbon) under initial conditions is calculated, moreover, the impact of carbon dioxide content on the physical properties(mainly including density, viscosity, specific heat at const pressure, surface tension, etc) of mixed liquor in oil production wells is analyzed in this paper. The comparison of the results shows that this model can meet the engineering needs with high accuracy.

  12. DENSE MEDIUM CYCLONE OPTIMIZATON

    SciTech Connect

    Gerald H. Luttrell; Chris J. Barbee; Peter J. Bethell; Chris J. Wood

    2005-06-30

    Dense medium cyclones (DMCs) are known to be efficient, high-tonnage devices suitable for upgrading particles in the 50 to 0.5 mm size range. This versatile separator, which uses centrifugal forces to enhance the separation of fine particles that cannot be upgraded in static dense medium separators, can be found in most modern coal plants and in a variety of mineral plants treating iron ore, dolomite, diamonds, potash and lead-zinc ores. Due to the high tonnage, a small increase in DMC efficiency can have a large impact on plant profitability. Unfortunately, the knowledge base required to properly design and operate DMCs has been seriously eroded during the past several decades. In an attempt to correct this problem, a set of engineering tools have been developed to allow producers to improve the efficiency of their DMC circuits. These tools include (1) low-cost density tracers that can be used by plant operators to rapidly assess DMC performance, (2) mathematical process models that can be used to predict the influence of changes in operating and design variables on DMC performance, and (3) an expert advisor system that provides plant operators with a user-friendly interface for evaluating, optimizing and trouble-shooting DMC circuits. The field data required to develop these tools was collected by conducting detailed sampling and evaluation programs at several industrial plant sites. These data were used to demonstrate the technical, economic and environmental benefits that can be realized through the application of these engineering tools.

  13. Cyclones in the thermosphere?

    NASA Astrophysics Data System (ADS)

    Burns, A.; Wang, W.; Killeen, T.

    2003-04-01

    The recovery of the thermosphere and ionosphere from geomagnetic storms is a subject that has not received the attention that it deserves. But, even with the small number of papers that have been published about these conditions, there are apparently conflicting results. Burns et al. (1989) suggested that most recovery was rapid, whereas Fuller-Rowell et al. (1994) found recovery was sufficiently slow that storm effects could be seen a full day after the end of the main phase of a geomagnetic storm. At first sight these two ideas do not seem to be easily reconciled. But, in fact, it is shown here that, while much recovery is fast at solar maximum, large, organized disturbances exist in the thermosphere and ionosphere for a long time. These disturbances, which were first proposed by Banks and Nagy (1974), are mesoscale- to large-scale in size and nature and have some characteristics of tropospheric cyclones. In this work, we discuss the nature of these disturbances, their origin and development and consider the processes that permit their long life. The major conclusions of this work are: 1) After a major geomagnetic storm neutral compositional recovery is rapid over much of the globe; 2) In certain areas, large-to-mesoscale disturbances occur that are both well organized and long lived; 3) The disturbance discussed here was "spun-off" from the dawn convection cell and then briefly formed a secondary horizontal vortex; 4) At times these disturbances are associated with pronounced vertical convection cells.

  14. Discontinuous Cyclone Movement of Mediterranean cyclones identified through formation analysis of daughter cyclones

    NASA Astrophysics Data System (ADS)

    Ziv, Baruch; Saaroni, Hadas; Harpaz, Tzvi

    2016-04-01

    A new algorithm developed performs an automated classification methodology for daughter cyclones (DCs) formation, with respect to the thermal field of the parent cyclones (PCs). The classification has been applied to winter Mediterranean Cyclones. The algorithm assigns a DC to one of seven types, according to the following considerations: Has the cyclone formed on a front? Is that a cold, a warm or a quasi-stationary front? Is this front part of the frontal system of the PC or of a non-parental system? If none of the above applies, has the cyclone formed within the warm sector? The measures used are the temperature gradient, temperature advection and temperature Laplacian, computed at the formation location of the DC and the temperature difference between the DC and the PC, each derived from the 850-hPa wind and temperature fields. Out of 4,303 DCs analyzed, 85% were identified to belong to one of the 7 predefined types, implying that 15% cannot be related to either baroclinic or thermal factors. More than half were formed at their PCs' frontal system, third on a non-parental frontal system and only 13% within the warm sector of the PC. Most of the cyclones, formed on the PC's cold front, were found at mountain lee locations, whereas cyclones formed on the warm front were generated mostly over the Aegean and the Adriatic Sea. The new methodology exposed a unique DC formation which is actually a Discontinuous Cyclone Movement (DCM), imposed by an encounter with geographical forcing. This formation was identified in 5.9% of the DC formations and is characterized by the following features: 1) parent-daughter distance (d) <1000 Km, 2) the area enclosed by the inner isobar surrounding both the PC and the DC should be less than 2d, 3) the PC should last no more than 18 hours after the DC has been first detected. DCM events found among DCs formed on warm fronts of PCs, to their east, are suggested as a mechanism which enables the PC to cross topographic barriers

  15. Effect of Schmidt number on mass transfer across a sheared gas-liquid interface in a wind-driven turbulence

    NASA Astrophysics Data System (ADS)

    Takagaki, Naohisa; Kurose, Ryoichi; Kimura, Atsushi; Komori, Satoru

    2016-11-01

    The mass transfer across a sheared gas-liquid interface strongly depends on the Schmidt number. Here we investigate the relationship between mass transfer coefficient on the liquid side, kL, and Schmidt number, Sc, in the wide range of 0.7 ≤ Sc ≤ 1000. We apply a three-dimensional semi direct numerical simulation (SEMI-DNS), in which the mass transfer is solved based on an approximated deconvolution model (ADM) scheme, to wind-driven turbulence with mass transfer across a sheared wind-driven wavy gas-liquid interface. In order to capture the deforming gas-liquid interface, an arbitrary Lagrangian-Eulerian (ALE) method is employed. Our results show that similar to the case for flat gas-liquid interfaces, kL for the wind-driven wavy gas-liquid interface is generally proportional to Sc‑0.5, and can be roughly estimated by the surface divergence model. This trend is endorsed by the fact that the mass transfer across the gas-liquid interface is controlled mainly by streamwise vortices on the liquid side even for the wind-driven turbulence under the conditions of low wind velocities without wave breaking.

  16. Effect of Schmidt number on mass transfer across a sheared gas-liquid interface in a wind-driven turbulence

    PubMed Central

    Takagaki, Naohisa; Kurose, Ryoichi; Kimura, Atsushi; Komori, Satoru

    2016-01-01

    The mass transfer across a sheared gas-liquid interface strongly depends on the Schmidt number. Here we investigate the relationship between mass transfer coefficient on the liquid side, kL, and Schmidt number, Sc, in the wide range of 0.7 ≤ Sc ≤ 1000. We apply a three-dimensional semi direct numerical simulation (SEMI-DNS), in which the mass transfer is solved based on an approximated deconvolution model (ADM) scheme, to wind-driven turbulence with mass transfer across a sheared wind-driven wavy gas-liquid interface. In order to capture the deforming gas-liquid interface, an arbitrary Lagrangian-Eulerian (ALE) method is employed. Our results show that similar to the case for flat gas-liquid interfaces, kL for the wind-driven wavy gas-liquid interface is generally proportional to Sc−0.5, and can be roughly estimated by the surface divergence model. This trend is endorsed by the fact that the mass transfer across the gas-liquid interface is controlled mainly by streamwise vortices on the liquid side even for the wind-driven turbulence under the conditions of low wind velocities without wave breaking. PMID:27841325

  17. Effect of Schmidt number on mass transfer across a sheared gas-liquid interface in a wind-driven turbulence.

    PubMed

    Takagaki, Naohisa; Kurose, Ryoichi; Kimura, Atsushi; Komori, Satoru

    2016-11-14

    The mass transfer across a sheared gas-liquid interface strongly depends on the Schmidt number. Here we investigate the relationship between mass transfer coefficient on the liquid side, kL, and Schmidt number, Sc, in the wide range of 0.7 ≤ Sc ≤ 1000. We apply a three-dimensional semi direct numerical simulation (SEMI-DNS), in which the mass transfer is solved based on an approximated deconvolution model (ADM) scheme, to wind-driven turbulence with mass transfer across a sheared wind-driven wavy gas-liquid interface. In order to capture the deforming gas-liquid interface, an arbitrary Lagrangian-Eulerian (ALE) method is employed. Our results show that similar to the case for flat gas-liquid interfaces, kL for the wind-driven wavy gas-liquid interface is generally proportional to Sc(-0.5), and can be roughly estimated by the surface divergence model. This trend is endorsed by the fact that the mass transfer across the gas-liquid interface is controlled mainly by streamwise vortices on the liquid side even for the wind-driven turbulence under the conditions of low wind velocities without wave breaking.

  18. DYNAMIC MODELING STRATEGY FOR FLOW REGIME TRANSITION IN GAS-LIQUID TWO-PHASE FLOWS

    SciTech Connect

    X. Wang; X. Sun; H. Zhao

    2011-09-01

    In modeling gas-liquid two-phase flows, the concept of flow regime has been used to characterize the global interfacial structure of the flows. Nearly all constitutive relations that provide closures to the interfacial transfers in two-phase flow models, such as the two-fluid model, are often flow regime dependent. Currently, the determination of the flow regimes is primarily based on flow regime maps or transition criteria, which are developed for steady-state, fully-developed flows and widely applied in nuclear reactor system safety analysis codes, such as RELAP5. As two-phase flows are observed to be dynamic in nature (fully-developed two-phase flows generally do not exist in real applications), it is of importance to model the flow regime transition dynamically for more accurate predictions of two-phase flows. The present work aims to develop a dynamic modeling strategy for determining flow regimes in gas-liquid two-phase flows through the introduction of interfacial area transport equations (IATEs) within the framework of a two-fluid model. The IATE is a transport equation that models the interfacial area concentration by considering the creation and destruction of the interfacial area, such as the fluid particle (bubble or liquid droplet) disintegration, boiling and evaporation; and fluid particle coalescence and condensation, respectively. For the flow regimes beyond bubbly flows, a two-group IATE has been proposed, in which bubbles are divided into two groups based on their size and shape (which are correlated), namely small bubbles and large bubbles. A preliminary approach to dynamically identifying the flow regimes is provided, in which discriminators are based on the predicted information, such as the void fraction and interfacial area concentration of small bubble and large bubble groups. This method is expected to be applied to computer codes to improve their predictive capabilities of gas-liquid two-phase flows, in particular for the applications in

  19. Gas-Liquid Interfacial Non-Equilibrium Plasmas for Structure Controlled Nanoparticles

    NASA Astrophysics Data System (ADS)

    Kaneko, Toshiro

    2013-10-01

    Plasmas generated in liquid or in contact with liquid have attracted much attention as a novel reactive field in the nano-bio material creation because the brand-new chemical and biological reactions are yielded at the gas-liquid interface, which are induced by the physical actions of the non-equilibrium plasmas. In this study, first, size- and structure-controlled gold nanoparticles (AuNPs) covered with DNA are synthesized using a pulse-driven gas-liquid interfacial discharge plasma (GLIDP) for the application to next-generation drug delivery systems. The size and assembly of the AuNPs are found to be easily controlled by changing the plasma parameters and DNA concentration in the liquid. On the other hand, the mono-dispersed, small-sized, and interval-controlled AuNPs are synthesized by using the carbon nanotubes (CNTs) as a template, where the CNTs are functionalized by the ion and radical irradiation in non-equilibrium plasmas. These new materials are now widely applied to the solar cell, optical devices, and so on. Second, highly-ordered periodic structures of the AuNPs are formed by transcribing the periodic plasma structure to the surface of the liquid, where the spatially selective synthesis of the AuNPs is realized. This phenomenon is well explained by the reduction and oxidation effects of the radicals which are generated by the non-equilibrium plasma irradiation to the liquid and resultant dissociation of the liquid. In addition, it is attempted to form nano- or micro-scale periodic structures of the AuNPs based on the self-organizing behavior of turbulent plasmas generated by the nonlinear development of plasma fluctuations at the gas-liquid interface.

  20. Microfabricated cylindrical ion trap

    DOEpatents

    Blain, Matthew G.

    2005-03-22

    A microscale cylindrical ion trap, having an inner radius of order one micron, can be fabricated using surface micromachining techniques and materials known to the integrated circuits manufacturing and microelectromechanical systems industries. Micromachining methods enable batch fabrication, reduced manufacturing costs, dimensional and positional precision, and monolithic integration of massive arrays of ion traps with microscale ion generation and detection devices. Massive arraying enables the microscale cylindrical ion trap to retain the resolution, sensitivity, and mass range advantages necessary for high chemical selectivity. The microscale CIT has a reduced ion mean free path, allowing operation at higher pressures with less expensive and less bulky vacuum pumping system, and with lower battery power than conventional- and miniature-sized ion traps. The reduced electrode voltage enables integration of the microscale cylindrical ion trap with on-chip integrated circuit-based rf operation and detection electronics (i.e., cell phone electronics). Therefore, the full performance advantages of microscale cylindrical ion traps can be realized in truly field portable, handheld microanalysis systems.

  1. Electrical impedance imaging in two-phase, gas-liquid flows: 1. Initial investigation

    NASA Technical Reports Server (NTRS)

    Lin, J. T.; Ovacik, L.; Jones, O. C.

    1991-01-01

    The determination of interfacial area density in two-phase, gas-liquid flows is one of the major elements impeding significant development of predictive tools based on the two-fluid model. Currently, these models require coupling of liquid and vapor at interfaces using constitutive equations which do not exist in any but the most rudimentary form. Work described herein represents the first step towards the development of Electrical Impedance Computed Tomography (EICT) for nonintrusive determination of interfacial structure and evolution in such flows.

  2. Gas liquid flow at microgravity conditions - Flow patterns and their transitions

    NASA Astrophysics Data System (ADS)

    Dukler, A. E.; Fabre, J. A.; McQuillen, J. B.; Vernon, R.

    The prediction of flow patterns during gas-liquid flow in conduits is central to the modern approach for modeling two phase flow and heat transfer. The mechanisms of transition are reasonably well understood for flow in pipes on earth where it has been shown that body forces largely control the behavior observed. This work explores the patterns which exist under conditions of microgravity when these body forces are suppressed. Data are presented which were obtained for air-water flow in tubes during drop tower experiments and Learjet trajectories. Preliminary models to explain the observed flow pattern map are evolved.

  3. On the Motion of an Annular Film in Microgravity Gas-Liquid Flow

    NASA Astrophysics Data System (ADS)

    McQuillen, John B.

    2002-11-01

    Three flow regimes have been identified for gas-liquid flow in a microgravity environment: Bubble, Slug, and Annular. For the slug and annular flow regimes, the behavior observed in vertical upflow in normal gravity is similar to microgravity flow with a thin, symmetrical annular film wetting the tube wall. However, the motion and behavior of this film is significantly different between the normal and low gravity cases. Specifically, the liquid film will slow and come to a stop during low frequency wave motion or slugging. In normal gravity vertical upflow, the film has been observed to slow, stop, and actually reverse direction until it meets the next slug or wave.

  4. Gas liquid flow at microgravity conditions - Flow patterns and their transitions

    NASA Technical Reports Server (NTRS)

    Dukler, A. E.; Fabre, J. A.; Mcquillen, J. B.; Vernon, R.

    1987-01-01

    The prediction of flow patterns during gas-liquid flow in conduits is central to the modern approach for modeling two phase flow and heat transfer. The mechanisms of transition are reasonably well understood for flow in pipes on earth where it has been shown that body forces largely control the behavior observed. This work explores the patterns which exist under conditions of microgravity when these body forces are suppressed. Data are presented which were obtained for air-water flow in tubes during drop tower experiments and Learjet trajectories. Preliminary models to explain the observed flow pattern map are evolved.

  5. Ground Based Studies of Gas-Liquid Flows in Microgravity Using Learjet Trajectories

    NASA Technical Reports Server (NTRS)

    Bousman, W. S.; Dukler, A. E.

    1994-01-01

    A 1.27 cm diameter two phase gas-liquid flow experiment has been developed with the NASA Lewis Research Center to study two-phase flows in microgravity. The experiment allows for the measurement of void fraction, pressure drop, film thickness and bubble and wave velocities as well as for high speed photography. Three liquids were used to study the effects of liquid viscosity and surface tension, and flow pattern maps are presented for each. The experimental results are used to develop mechanistically based models to predict void fraction, bubble velocity, pressure drop and flow pattern transitions in microgravity.

  6. Acoustic probe for solid-gas-liquid suspensions. 1997 annual progress report

    SciTech Connect

    Tavlarides, L.L.; Sangani, A.S.

    1997-01-01

    'Acoustic probes have shown promise to be quite effective in determining the solid content in solid-liquid suspensions. However, the presence of small amounts of gas in the waste slurries stored in tanks across the DOE complex prevents straightforward application for characterization of these slurries. The proposed research will develop an acoustic probe for monitoring particle size and volume fraction in slurries in the absence and the presence of gas bubbles. Theoretical Analysis Accomplished: Attenuation of sound waves depends on the size distribution of the solids and the volume fraction of solids. These can in principle be calculated from attenuation measured over a range of frequencies. However, small amounts of bubbles distort the measured attenuation. A typical result from theoretical analysis for the attenuation of solid- gas-liquid systems is given in Figure 1. The total attenuation of a sound wave v(o) equals the sum of contributions by a large number of ''bins'' of particle sizes. This notion yields the following equation for the (hitherto) unknown number density of solid particles as a function of particle radius N(a): j k(o,a)N(a)da = v(o), where the kernel k(o,a) is obtained from analysis. If N(a) is given, the above equation is used to calculate the attenuation v(o). This is referred to as solving the ''forward problem''. Solving for N(a) with v(o) given is the ''inverse problem''. A complication that one faces when trying to solve the inverse problem is that the stated problem is mathematically ill-posed, i.e., small fluctuations in v(o) cause large fluctuations in the result for the number density. Therefore the problem needs to be ''regularized'', i.e., the stated problem needs to be changed slightly such as to make it well-posed. This has been done by others for gas-liquid systems in the past. This approach is currently being applied in the present project to solid-liquid systems. As is shown in Figure 2, it successfully recovers the number

  7. Prediction of gas-liquid two-phase flow regime in microgravity

    NASA Technical Reports Server (NTRS)

    Lee, Jinho; Platt, Jonathan A.

    1993-01-01

    An attempt is made to predict gas-liquid two-phase flow regime in a pipe in a microgravity environment through scaling analysis based on dominant physical mechanisms. Simple inlet geometry is adopted in the analysis to see the effect of inlet configuration on flow regime transitions. Comparison of the prediction with the existing experimental data shows good agreement, though more work is required to better define some physical parameters. The analysis clarifies much of the physics involved in this problem and can be applied to other configurations.

  8. Gas-liquid chromatographic determination of 3-trifluoromethyl-4-nitrophenol residues in fish

    USGS Publications Warehouse

    Allen, J.L.; Sills, J.B.

    1974-01-01

    A procedure for the determination of 3-mftuormethyl-4-nitrophenol (TFM) in fish tissues is described. Homogenized tissues are extracted with hexane-ethyl ether; the extract is cleaned up by partitioning the TFM from the extracting solvent into O.IN NaOB, acidifying the aqueous solution, and partitioning again with hexaneethyl ether. The TFM is methylated with diazomethane and analyzed by gas-liquid chromatography, using electron capture detection. Recoveries ranged from 75 to 1000/., from fish muscles that were spiked with 0.01-2.00 JA#g TFM/g.

  9. Generalization of low pressure, gas-liquid, metastable sound speed to high pressures

    NASA Technical Reports Server (NTRS)

    Bursik, J. W.; Hall, R. M.

    1981-01-01

    A theory is developed for isentropic metastable sound propagation in high pressure gas-liquid mixtures. Without simplification, it also correctly predicts the minimum speed for low pressure air-water measurements where other authors are forced to postulate isothermal propagation. This is accomplished by a mixture heat capacity ratio which automatically adjusts from its single phase values to approximately the isothermal value of unity needed for the minimum speed. Computations are made for the pure components parahydrogen and nitrogen, with emphasis on the latter. With simplifying assumptions, the theory reduces to a well known approximate formula limited to low pressure.

  10. Mesoscale Processes in Tropical Cyclones

    DTIC Science & Technology

    2016-06-07

    available work relates to forecast rules relating the observed effects of external processes on the convective structure (e.g. Merrill 1993). Whilst the...cyclone could not exist without moist convection , we have found that some cloud processes also provide an inhibition to intensification. An example is

  11. Tropical Cyclone Ensemble Data Assimilation

    DTIC Science & Technology

    2012-09-30

    described above, but using a vertical window of influence of 2.0 times the scale hight . Notice that meaningful vertical correlation is found by LETKF...between the scatterometer observation and many points throughout the troposphere. This suggests that for assimilation near tropical cyclones that have

  12. System Developed for Bulk Flow Imaging of a Two-Phase Fluid in a Cylindrical Couette

    NASA Technical Reports Server (NTRS)

    Juergens, Jeffrey R.; Wagner, James D.

    2005-01-01

    The Microgravity Observation of Bubble Interactions (MOBI) experiment is working to better understand the physics of gas-liquid suspensions. To study such suspensions, researchers generate bubbles in a large cylindrical flow channel. Then, they use various types of instrumentation, including video imaging, to study the bubbly suspension. Scientists will need a camera view of the majority of the gas-liquid suspension inside of the couette in order to gather the information needed from the MOBI experiment. This will provide the scientists with a qualitative picture of the flow that may indicate flow instabilities or imperfect axial mixing inside the couette. These requirements pose a significant challenge because the imaging and lighting system must be confined to a very tight space since the space available on the International Space Station experiment racks is very limited. In addition, because of the large field of view needed and the detail needed to see the gas-liquid suspension behavior in the image, a digital video camera with high resolution (1024 by 1024 pixels) had to be used. Although the high-resolution camera will provide scientists with the image quality they need, it left little space on the experiment rack for the lighting system. Many configurations were considered for the lighting system, including front-lighting and back-lighting, but because of mechanical design limitations with the couette, back-lighting was not an option.

  13. APR-2 Tropical Cyclone Observations

    NASA Technical Reports Server (NTRS)

    Durden, S. L.; Tanelli, S.

    2011-01-01

    The Second Generation Airborne Precipitation Radar (APR-2) participated in the Genesis and Rapid Intensification Processes (GRIP) experiment in August and September of 2010, collecting a large volume of data in several tropical systems, including Hurricanes Earl and Karl. Additional measurements of tropical cyclone have been made by APR-2 in experiments prior to GRIP (namely, CAMEX-4, NAMMA, TC4); Table 1 lists all the APR-2 tropical cyclone observations. The APR-2 observations consist of the vertical structure of rain reflectivity at 13.4 and 35.6 GHz, and at both co-polarization and crosspolarization, as well as vertical Doppler measurements and crosswind measurements. APR-2 normally flies on the NASA DC-8 aircraft, as in GRIP, collecting data with a downward looking, cross-track scanning geometry. The scan limits are 25 degrees on either side of the aircraft, resulting in a roughly 10-km swath, depending on the aircraft altitude. Details of the APR-2 observation geometry and performance can be found in Sadowy et al. (2003).The multiparameter nature of the APR-2 measurements makes the collection of tropical cyclone measurements valuable for detailed studies of the processes, microphysics and dynamics of tropical cyclones, as well as weaker systems that are associated with tropical cyclone formation. In this paper, we give a brief overview of how the APR-2 data are processed. We also discuss use of the APR-2 cross-track winds to estimate various quantities of interest in in studies of storm intensification. Finally, we show examples of the standard products and derived information.

  14. Flow behaviour and transitions in surfactant-laden gas-liquid vertical flows

    NASA Astrophysics Data System (ADS)

    Zadrazil, Ivan; Chakraborty, Sourojeet; Matar, Omar; Markides, Christos

    2016-11-01

    The aim of this work is to elucidate the effect of surfactant additives on vertical gas-liquid counter-current pipe flows. Two experimental campaigns were undertaken, one with water and one with a light oil (Exxsol D80) as the liquid phase; in both cases air was used as the gaseous phase. Suitable surfactants were added to the liquid phase up to the critical micelle concentration (CMC); measurements in the absence of additives were also taken, for benchmarking. The experiments were performed in a 32-mm bore and 5-m long vertical pipe, over a range of superficial velocities (liquid: 1 to 7 m/s, gas: 1 to 44 m/s). High-speed axial- and side-view imaging was performed at different lengths along the pipe, together with pressure drop measurements. Flow regime maps were then obtained describing the observed flow behaviour and related phenomena, i.e., downwards/upwards annular flow, flooding, bridging, gas/liquid entrainment, oscillatory film flow, standing waves, climbing films, churn flow and dryout. Comparisons of the air-water and oil-water results will be presented and discussed, along with the role of the surfactants in affecting overall and detailed flow behaviour and transitions; in particular, a possible mechanism underlying the phenomenon of flooding will be presented. EPSRC UK Programme Grant EP/K003976/1.

  15. Lagrangian coherent structures analysis of gas-liquid flow in a bubble column

    NASA Astrophysics Data System (ADS)

    Wu, Qin; Wang, GuoYu; Huang, Biao; Bai, ZeYu

    2014-06-01

    The objective of this paper is to apply a new identifying method to investigating the gas-liquid two-phase flow behaviors in a bubble column with air injected into water. In the numerical simulations, the standard k- ɛ turbulence model is employed to describe the turbulence phenomenon occurring in the continuous fluid. The Finite-Time Lyapunov Exponent (FTLE) and Lagrangian Coherent Structures (LCS) are applied to analyze the vortex structures in multiphase flow. Reasonable agreements are obtained between the numerical and experimental data. The numerical results show that the evolution of gas-liquid in the column includes initial and periodical developing stages. During the initial stage, the bubble hose is forming and extending along the vertical direction with the vortex structures formed symmetrically. During the periodical developing stage, the bubble hose starts to oscillate periodically, and the vortexes move along the bubble hose to the bottom of column alternately. Compared to the Euler-system-based identification criterion of a vortex, the FTLE field presents the boundary of a vortex without any threshold defined and the LCS represents the divergence extent of infinite neighboring particles. During the initial stage, the interfaces between the forward and backward flows are highlighted by the LCS. As for the periodical developing stage, the LCS curls near the vortex centers, providing a method of analyzing a flow field from a dynamical system perspective.

  16. Centrifugal scaling of isothermal gas-liquid flows in horizontal tubes

    NASA Astrophysics Data System (ADS)

    Geraets, Jacques Joseph Marie

    1986-05-01

    To test the similarity criteria of two-phase gas-liquid flows, arising from the governing equations and boundary conditions, the flow of air and a water-glycerine mixture in a 50 mm diameter horizontal tube is compared with a two-phase flow of helium and water in a 5 mm diameter tube rotating around a parallel vertical axis (the effective gravity is 113 g0). Results emphasize that in general only dimensionless correlations provide meaningful predictions. The homogeneous Dukler case 1 (1964b) correlation, which contains no two-phase information, provides the best fit (the standard deviation is 21%) with the measured pressure drops. For predicting flow pattern the most promising approach is that of Taitel and Dukler (1976). Examples of scaling down large diameter, high pressure pipelines are presented. With a scale factor of 1/30 equality of the Froude number, the gas-liquid density ratio, and either the Reynolds number or the Weber number can be realized. Compressibility and gas viscosity are not properly scaled.

  17. Spatio-temporal evolution of interfacial instabilities in vertical gas-liquid flows

    NASA Astrophysics Data System (ADS)

    Schmidt, Patrick; Valluri, Prashant; Ó Náraigh, Lennon; Lucquiaud, Mathieu

    2014-11-01

    Vertical gas-liquid flows are characteristic for process engineering and widely employed in various technical applications. However, the dynamic behaviour of the liquid interface in such flows is still not fully understood. We focus in our work on characterising the interfacial instability as well as associated interfacial waves in vertical laminar-laminar gas-liquid flows over a wide range of parameters covering different flow regimes, i.e. counter-current, zero-interface velocity (loading) and partial-to-full liquid flow reversal (flooding). High-resolution direct numerical simulations using the TPLS flow solver (http://sourceforge.net/projects/tpls/) reveal the existence of weakly nonlinear interfacial waves, which are in good agreement with Stuart-Landau theory. These waves travel down- or upstream, depending on the flow regime. Furthermore, spatio-temporal linear stability analysis indicates the occurrence of absolute instability within the investigated parameter range. DNS is used to analyse this feature in more detail whereby agreement with linear theory has been established.

  18. Evaluation of high-efficiency gas liquid contactors for natural gas processing

    SciTech Connect

    Palla, N.; Lee, A.L.

    1995-06-01

    The objectives of this program are to develop and evaluate advanced processing technologies that can reduce the cost of upgrading sub quality natural gas to pipeline standards. The successful application of cost-effective, new technologies will facilitate the production of sub quality natural gas that otherwise would be too expensive to produce. The overall program is focused on the following activities: evaluation of the potential of structured packing for the removal of acid gases from natural gases, and expansion of the currently available database of the fluid dynamics of rotating gas liquid contactors. The natural gas sweetening, structured packing field tests are scheduled to be conducted in calendar year 1995. Design, procurement and construction of the field test unit. Expansion of the available data base on the hydraulic characteristics of a rotating gas-liquid contactor is being pursued through a series of laboratory experiments. A 100 GPM, low pressure rotary contactor system has been assembled at IGT`s Energy Development Center to examine the fluid dynamic behavior of this type of contactor. The studies are determining the effects of liquid viscosity, liquid surface tension and operating conditions on liquid residence times and flooding limits.

  19. A compressible two-layer model for transient gas-liquid flows in pipes

    NASA Astrophysics Data System (ADS)

    Demay, Charles; Hérard, Jean-Marc

    2017-03-01

    This work is dedicated to the modeling of gas-liquid flows in pipes. As a first step, a new two-layer model is proposed to deal with the stratified regime. The starting point is the isentropic Euler set of equations for each phase where the classical hydrostatic assumption is made for the liquid. The main difference with the models issued from the classical literature is that the liquid as well as the gas is assumed compressible. In that framework, an averaging process results in a five-equation system where the hydrostatic constraint has been used to define the interfacial pressure. Closure laws for the interfacial velocity and source terms such as mass and momentum transfer are provided following an entropy inequality. The resulting model is hyperbolic with non-conservative terms. Therefore, regarding the homogeneous part of the system, the definition and uniqueness of jump conditions is studied carefully and acquired. The nature of characteristic fields and the corresponding Riemann invariants are also detailed. Thus, one may build analytical solutions for the Riemann problem. In addition, positivity is obtained for heights and densities. The overall derivation deals with gas-liquid flows through rectangular channels, circular pipes with variable cross section and includes vapor-liquid flows.

  20. Observation of Gas-Liquid Flow Near the Exit Orifice of An Effervescent Atomizer

    NASA Astrophysics Data System (ADS)

    Sun, C. H.; Ning, Z.; Lü, M.; Fu, J.; Li, Y. X.

    For deepen the understanding of the mechanism of effervescent atomization: it is necessary to have a better observation on the gas-liquid flow near the exit orifice. Both image and acoustic ways were introduced to observe the gas-fluid flow by a transparent effervescent atomizer. The results show that: It can be clearly seen from images that internal flow regimes make great influence on the spray behavior. Spray acoustic observation is an effective way to grasp the gas-liquid two phases flow behavior when they ejecting from the exit orifice. The acoustic analyzing in time and frequency domain has the ability to obtain the discrete phenomenon existing in effervescent sprays, in thus way, acoustic features could give a new perspective on effervescent spray over time. What's more, the discrete phenomenon in dilute bubbly flow and slug flow can be easily captured from after acoustic analyzing. Uniform two-phase distribution of internal flow shows continues acoustic performance after observing the homogeneous bubbly flow and chum flow.

  1. Resolution of diacylglycerol moieties of natural glycerophospholipids by gas-liquid chromatography on polar capillary columns.

    PubMed

    Myher, J J; Kuksis, A

    1982-06-01

    A rapid and practical method has been developed for the gas-liquid chromatographic determination of the sn-1,2-diacylglycerol moieties of natural glycerophospholipids using polar wall-coated open tubular columns. The method gives complete resolution and quantitative estimates for all species according to molecular weight and degree of unsaturation, including stearoyl docosahexaenoylglycerol and related polyunsaturates. For this purpose the sn-1,2-diacylglycerols are obtained from the glycerophospholipids by hydrolysis with phospholipase C and are converted into the trimethylsilyl or tertiary-butyldimethylsilyl ethers. The silyl ethers are separated by gas-liquid chromatography on the capillary glass columns coated with a polar cyanopropylsiloxane polymer, in the temperature range 175-250 degrees C, using hydrogen as the carrier gas. Practical applications of the method are illustrated by analyses of the sn-1,2-diacylglycerol moieties of the phosphatidylcholines of soybean phosphatides, egg yolk, and rat liver. The method of analysis is applicable to other classes of glycerophospholipids and the total time requirements for the analysis of any one phospholipid class are comparable to those for a fatty acid analysis.

  2. Decomposition of phenol by hybrid gas/liquid electrical discharge reactors with zeolite catalysts.

    PubMed

    Kusić, Hrvoje; Koprivanac, Natalija; Locke, Bruce R

    2005-10-17

    Application of hybrid gas/liquid electrical discharge reactors and a liquid phase direct electrical discharge reactor for degradation of phenol in the presence and absence of zeolites have been investigated. Hybrid gas/liquid electrical discharges involve simultaneous high voltage electrical discharges in water and in the gas phase above the water surface leading to the additional OH radicals in the liquid phase and ozone formation in the gas phase with subsequent dissolution into the liquid. The role of applied zeolites, namely NH4ZSM5, FeZSM5 and HY, were also studied. Phenol degradation and production of primary phenol by-products, catechol and hydroquinone, during the treatment were monitored by HPLC measurements. The highest phenol removal results, 89.4-93.6%, were achieved by electrical discharge in combination with FeZSM5 in all three configurations of corona reactors. These results indicate that the Fenton reaction has significant influence on overall phenol removal efficiency in the electrical discharge/FeZSM5 system due to the additional OH radical formation from hydrogen peroxide generated by the water phase discharge.

  3. Simulation of drag reduction in superhydrophobic microchannels based on parabolic gas-liquid interfaces

    NASA Astrophysics Data System (ADS)

    Li, Chunxi; Zhang, Shuo; Xue, Quanxi; Ye, Xuemin

    2016-10-01

    Based on the given parabolic gas-liquid interfaces, a two-dimensional fluid flow in superhydrophobic microchannels is numerically simulated with the steady volume of fluid model in the laminar regime. The influence of several crucial parameters on drag reduction effect is discussed. The results indicate that the superhydrophobic microchannel containing rectangular cavities displays significant drag reduction effect. With increasing inlet velocity, the pressure drop reduction decreases slightly. Augments in the pressure drop reduction tend to be large with the increase of the cavity fraction or the decrease of the channel height. The results also reveal that the variation of the normalized slip length with the cavity fraction tends to be more dramatic when the channel height is smaller. As the parabolic height of the gas-liquid interface is enlarged, both the pressure drop reduction and the normalized slip length decrease linearly, while fRe increases linearly. The impact of the cavity depth on the normalized slip length, fRe, and the pressure drop reduction is minimal supposing the depth of the cavity is greater than 40% of its width. The drag reduction effect corresponding to the dovetail cavity model is the best, and the consequence of the rectangular, trapezoidal, and triangular cavity models sequentially worsens.

  4. Shadow imaging in bubbly gas-liquid two-phase flow in porous structures

    NASA Astrophysics Data System (ADS)

    Altheimer, Marco; Häfeli, Richard; Wälchli, Carmen; Rudolf von Rohr, Philipp

    2015-09-01

    Shadow imaging is used for the investigation of bubbly gas-liquid two-phase flow in a porous structure. The porous structure is made of Somos WaterShed XC 11122, a clear epoxy resin used in rapid prototyping. Optical access is provided by using an aqueous solution of sodium iodide and zinc iodide having the same refractive index as the structure material (). Nitrogen is injected into the continuous phase at volumetric transport fractions in the range of resulting in a hold-up of . The obtained images of overlapping bubble shadows are processed to measure the bubble dimensions. Therefore, a new processing sequence is developed to determine bubble dimensions from overlapping bubble shadows by ellipse fitting. The accuracy of the bubble detection and sizing routine is assessed processing synthetic images. It is shown that the developed technique is suitable for volumetric two-phase flow measurements. Important global quantities such as gas hold-up and total interfacial area can be measured with only one camera. Operation parameters for gas-liquid two-phase flows are determined to improve mass and heat transfer between the phases.

  5. A flow reactor setup for photochemistry of biphasic gas/liquid reactions

    PubMed Central

    Schachtner, Josef; Bayer, Patrick

    2016-01-01

    Summary A home-built microreactor system for light-mediated biphasic gas/liquid reactions was assembled from simple commercial components. This paper describes in full detail the nature and function of the required building elements, the assembly of parts, and the tuning and interdependencies of the most important reactor and reaction parameters. Unlike many commercial thin-film and microchannel reactors, the described set-up operates residence times of up to 30 min which cover the typical rates of many organic reactions. The tubular microreactor was successfully applied to the photooxygenation of hydrocarbons (Schenck ene reaction). Major emphasis was laid on the realization of a constant and highly reproducible gas/liquid slug flow and the effective illumination by an appropriate light source. The optimized set of conditions enabled the shortening of reaction times by more than 99% with equal chemoselectivities. The modular home-made flow reactor can serve as a prototype model for the continuous operation of various other reactions at light/liquid/gas interfaces in student, research, and industrial laboratories. PMID:27829887

  6. Hilly Surroundings (cylindrical)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This 360-degree view of the terrain surrounding NASA's Mars Exploration Rover Spirit was taken on the rover's 189th sol on Mars (July 15, 2004). It was assembled from images taken by the rover's navigation camera at a position referred to as Site 72, which is at the base of the 'West Spur' portion of the 'Columbia Hills.' The view is presented in a cylindrical projection with geometrical seam correction.

  7. Static cylindrically symmetric spacetimes

    NASA Astrophysics Data System (ADS)

    Fjällborg, Mikael

    2007-05-01

    We prove the existence of static solutions to the cylindrically symmetric Einstein Vlasov system, and we show that the matter cylinder has finite extension in two of the three spatial dimensions. The same results are also proved for a quite general class of equations of state for perfect fluids coupled to the Einstein equations, extending the class of equations of state considered by Bicak et al (2004 Class. Quantum Grav.21 1583). We also obtain this result for the Vlasov Poisson system.

  8. Basic study on an energy conversion system using gas-liquid two-phase flows of magnetic fluid

    SciTech Connect

    Okubo, Masaaki; Ishimoto, Jun; Kamiyama, Schinichi.

    1994-12-31

    The mechanism of the pressure rise in a gas-liquid two-phase pipe flow of magnetic fluid under a nonuniform magnetic field is investigated in detail both theoretically and experimentally. First, governing equations of one-dimensional gas-liquid two-phase magnetic fluid flow are presented and numerically solved. Next, the pressure distribution in a nonuniform magnetic wild region is measured in the cases of two-phase flow, single-phase flow and the stationary state using a new experimental apparatus for the flow system. From the numerical measurement results, the magnitude of the pressure components which contribute to the total driving force is accurately estimated. These results on the pressure distribution will contribute to the development of the new energy conversion system using a gas-liquid two-phase magnetic fluid flow.

  9. A new contactless impedance sensor for void fraction measurement of gas-liquid two-phase flow

    NASA Astrophysics Data System (ADS)

    Ji, Haifeng; Chang, Ya; Huang, Zhiyao; Wang, Baoliang; Li, Haiqing

    2016-12-01

    With impedance elimination principle and phase sensitive demodulation (PSD) technique, this work aims to develop a new contactless impedance sensor, which is suitable for the void fraction measurement of gas-liquid two-phase flow. The impedance elimination principle is used to overcome the unfavorable influences of the coupling capacitances, i.e. the capacitive reactances of the coupling capacitances are eliminated by the inductive reactance of an introduced inductor. PSD technique is used to implement the impedance measurement. Unlike the conventional conductance/impedance sensors which use the equivalent conductance (the real part of the impedance) or the amplitude of the impedance of gas-liquid two-phase flow, the new contactless impedance sensor makes full use of the total impedance information of gas-liquid two-phase flow (including the amplitude, the real part and the imaginary part of the impedance, especially the imaginary part) to implement the void fraction measurement. As a preliminary study, to verify the effectiveness of the new contactless impedance sensor, two prototypes (with different inner diameters of 17.0 mm and 22.0 mm) are developed and experiments are carried out. Two typical flow patterns (bubble flow and stratified flow) of gas-liquid two-phase flow are investigated. The experimental results show that the new contactless impedance sensor is successful and effective. Compared with the conventional conductance/impedance sensors, the new contactless impedance sensor can avoid polarization effect and electrochemical erosion effect. The total impedance information is used and the void fraction measurement performance of the new sensor is satisfactory. The experimental results also indicate that the imaginary part of the impedance of gas-liquid two-phase flow is very useful for the void fraction measurement. Making full use of the total impedance information of gas-liquid two-phase flow can effectively improve the void fraction measurement

  10. Colloidal gas-liquid condensation of polystyrene latex particles with intermediate kappa a values (5 to 160, a > kappa(-1)).

    PubMed

    Ishikawa, Masamichi; Kitano, Ryota

    2010-02-16

    Polystyrene latex particles showed gas-liquid condensation under the conditions of large particle radius (a > kappa(-1)) and intermediate kappa a, where kappa is the Debye-Hückel parameter and a is the particle radius. The particles were dissolved in deionized water containing ethanol from 0 to 77 vol %, settled to the bottom of the glass plate within 1 h, and then laterally moved toward the center of a cell over a 20 h period in reaching a state of equilibrium condensation. All of the suspensions that were 1 and 3 microm in diameter and 0.01-0.20 vol % in concentration realized similar gas-liquid condensation with clear gas-liquid boundaries. In 50 vol % ethanol solvent, additional ethanol was added to enhance the sedimentation force so as to restrict the particles in a monoparticle layer thickness. The coexistence of gas-liquid-solid (crystalline solid) was microscopically recognized from the periphery to the center of the condensates. A phase diagram of the gas-liquid condensation was created as a function of KCl concentration at a particle diameter of 3 microm, 0.10 vol % concentration, and 50:50 water/ethanol solvent at room temperature. The miscibility gap was observed in the concentration range from 1 to 250 microM. There was an upper limit of salt concentration where the phase separation disappeared, showing nearly critical behavior of macroscopic density fluctuation from 250 microM to 1 mM. These results add new experimental evidence to the existence of colloidal gas-liquid condensation and specify conditions of like-charge attraction between particles.

  11. Annual Tropical Cyclone Report 1980

    DTIC Science & Technology

    1980-01-01

    overall smoothed track, which may have been followed by Orchid at some level above 700 mb. An analogy which may offer some in- A sight into Orchid’s...020000Z October, however, the disturbance had weakening, rather than by a typical smooth , separated from the inflow into Vernon, and gradual...or smoothed tracks of straight,’recurving, and all other prognostic field at designated levels in 6- cyclones that do not meet the criteria of hour

  12. The Dynamics of Tropical Cyclones

    DTIC Science & Technology

    2016-06-07

    include three different representations of cumulus convection . Realistic simulations of hurricanes have been carried out with the model. The model...tropical cyclones. We have completed a study of the convective destabilization by an approaching upper level trough and a joint paper on this topic with a...the study has been accepted for publication (Thorncroft and Jones, 2000). We have prepared a review paper on the role of cumulus convection in

  13. Paradigms for Tropical Cyclone Intensification

    DTIC Science & Technology

    2014-03-01

    Tang and Emanuel 2010 and references), it is imperative to have a firm understanding of the physical processes of intensity change for...defensible when studying the basic physics of tropical cyclone intensification (Nguyen et al. 2008, section 3.2.1), but not, of course, for tropical...They recalled that the premise underlying all physical parameteriszations is that some aspect of the chaotic microscale process is in statistical

  14. Structure of Developing Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Molinari, J. E.

    2006-12-01

    Considerable progress has been made in the numerical modeling of tropical cyclones. The very high resolution now routinely used in research models allows realistic simulation of eyewall structure and breakdown, vortex Rossby waves, and numerous other processes that were beyond the capability of previous generations of models. At least one aspect of tropical cyclones, however, has not been reproduced in the current generation of models: early development (or lack of development) during tropical depression and early tropical storm stages. During such times, vertical wind shear often plays a critical role. In this presentation, details of the structure of four tropical cyclones at early stages will be given: Claudette (2003), Danny (1997), Gabrielle (2001), and Edouard (2002). The first three contained intense vortices that formed within downshear convection. Deep-layer vertical wind shear ranged from 8-15 m/s in the storms. In Claudette, a hurricane formed that lasted only 6 hours. In Danny and Gabrielle, the downshear vortices became the new storm center. One became a hurricane and one did not. In Edouard, vertical shear was even larger. Convection fluctuated between downshear of the center and over the center, with analogous intensity changes. This behavior is known to forecasters, but the causes of such fluctuations remain uncertain. The evolving structure of these four storms will be shown, with emphasis on the variation of convection, equivalent potential temperature in the lower troposphere, and azimuthal asymmetries of wind and circulation. Contrast will be made between the structure of forming tropical cyclones in nature and those seen in mesoscale numerical models. Some remarks will be given on the key physical processes that must be simulated.

  15. Promoting the confluence of tropical cyclone research.

    PubMed

    Marler, Thomas E

    2015-01-01

    Contributions of biologists to tropical cyclone research may improve by integrating concepts from other disciplines. Employing accumulated cyclone energy into protocols may foster greater integration of ecology and meteorology research. Considering experienced ecosystems as antifragile instead of just resilient may improve cross-referencing among ecological and social scientists. Quantifying ecosystem capital as distinct from ecosystem services may improve integration of tropical cyclone ecology research into the expansive global climate change research community.

  16. Promoting the confluence of tropical cyclone research

    PubMed Central

    Marler, Thomas E

    2015-01-01

    Contributions of biologists to tropical cyclone research may improve by integrating concepts from other disciplines. Employing accumulated cyclone energy into protocols may foster greater integration of ecology and meteorology research. Considering experienced ecosystems as antifragile instead of just resilient may improve cross-referencing among ecological and social scientists. Quantifying ecosystem capital as distinct from ecosystem services may improve integration of tropical cyclone ecology research into the expansive global climate change research community. PMID:26480001

  17. Critical lines for a generalized three state binary gas-liquid lattice model

    NASA Astrophysics Data System (ADS)

    Meijer, Paul H. E.; Keskin, Mustafa; Pegg, Ian L.

    1988-02-01

    The critical properties of several compressible binary gas-liquid models are described: the three state lattice gas, the Tompa model for polymer solutions, the van der Waals equation for binary mixtures, and an intermediate model. The critical lines are expressed as functions of x1 and x2, the density of type 1 molecules and the density of type 2 molecules, instead of using the pressure and temperature; representative figures are given for each of the models. The general conditions for criticality, stability, and tricriticality are given as functions of x1 and x2 through the intermediary of the spinodal temperature function T(x1,x2). A closed form solution is given for the Berthelot case (geometrical-mean combining rule). All the models exhibit a characteristic intersection of two critical lines, and the behavior near this point is investigated. In the van der Waals case we confirm the coordinates given by van Laar.

  18. Gas-liquid chromatography-mass spectrometry of synthetic ceramides containing phytosphingosine.

    PubMed

    Hammarström, S

    1970-05-01

    Ceramides containing phytosphingosine as base and one of the fatty acids 16:0, 18:0, 20:0, 22:0, 23:0, and 24:0, were prepared by direct coupling in the presence of a mixed carbodiimide. The ceramides were analyzed as the 1,3,4-tri-O-trimethylsilyl ether derivatives by gas-liquid chromatography-mass spectrometry. Gas chromatographic data is presented, and structures of mass spectral ions are suggested. The structures are supported by mass spectra of the homologous ceramides, by deuterium-labeling experiments, and by high resolution mass spectrometry. Some ions, formed by cleavage between C-3 and C-4 in the long-chain base, indicate the phytosphingosine nature of the ceramide.

  19. Thermal dispersion in vertical gas-liquid flows with foaming and non-foaming liquids

    SciTech Connect

    Pino, L.R.Z.; Saez, A.E.

    1995-05-01

    Heat transfer experiments have been performed in gas-liquid upwards flow in a vertical column with non-foaming (water) and foaming (kerosene) liquids. The main purpose of the experiments has been to characterized the degree of thermal mixing in the system. For the range of conditions employed, the nonfoaming liquid exhibits complete mixing a low liquid superficial velocities. An increased in liquid velocity leads to incomplete mixing. In the latter case, the thermal dispersion coefficient at low gas superficial velocities is larger than what correlations in the literature predict. For the foaming liquid, when foaming and bubbling regions coexist in the bubble column, each region behaves as a completely-mixed subsystem.

  20. An effective device for gas-liquid oxygen removal in enclosed microalgae culture.

    PubMed

    Su, Zhenfeng; Kang, Ruijuan; Shi, Shaoyuan; Cong, Wei; Cai, Zhaoling

    2010-01-01

    A high-performance gas-liquid transmission device (HPTD) was described in this paper. To investigate the HPTD mass transfer characteristics, the overall volumetric mass transfer coefficients, K(A)(La,CO(2)) for the absorption of gaseous CO(2) and K(A)(La,O(2)) for the desorption of dissolved O(2) were determined, respectively, by titration and dissolved oxygen electrode. The mass transfer capability of carbon dioxide was compared with that of dissolved oxygen in the device, and the operating conditions were optimized to suit for the large-scale enclosed micro-algae cultivation. Based on the effectiveness evaluation of the HPTD applied in one enclosed flat plate Spirulina culture system, it was confirmed that the HPTD can satisfy the demand of the enclosed system for carbon supplement and excessive oxygen removal.

  1. Studies of momentum and energy transfer across wavy gas-liquid interfaces. Final report

    SciTech Connect

    Dukler, A.E.

    1993-06-01

    Two phase gas-liquid flow and its associated interfaces exist in a wide variety of situations of importance to the Navy and this has prompted the study of the basic flow mechanics which underlie this complex process. The existence of wind-wave interactions over large bodies of water have long been recognized as a special case of two phase flow where the presence of the deformable interface plays a complex role in the generation of waves due to the action of the wind. Less well recognized, but of great importance, are situations of two phase flow which are found in components of power systems such as condensers, boilers refrigeration loops and cryogen lines. Here the characteristics of two phase flow are critical to the reliable design and safe operation of such systems.

  2. Correlation of the "EMIT" antiepileptic drug assay with a gas liquid chromatographic method.

    PubMed

    Legaz, M; Raisys, V A

    1976-02-01

    Many methodologies have been developed for determining anticonvulsant drug levels in human serum. Unfortunately, most procedures are either time consuming or subject to a variety of interferring substances. The "Enzyme Multiplied Immunoassay Technique" (EMIT) system has been evaluated for its speed, sensitivity, accuracy, and precision. When compared with a gas-liquid chromatographic procedure, the EMIT assay appeared to yield results which were statistically comparable for the drugs diphenylhydantoin, phenobarbital, and primidone. The EMIT assay also demonstrated no significant interference when challenged with extraordinarily high levels of potentially cross reacting drugs. Results obtained with the EMIT assay correlated well with GLC data and rank it as an attractive alternative to many of the existing procedures now being used.

  3. Unit operations for gas-liquid mass transfer in reduced gravity environments

    NASA Technical Reports Server (NTRS)

    Pettit, Donald R.; Allen, David T.

    1992-01-01

    Basic scaling rules are derived for converting Earth-based designs of mass transfer equipment into designs for a reduced gravity environment. Three types of gas-liquid mass transfer operations are considered: bubble columns, spray towers, and packed columns. Application of the scaling rules reveals that the height of a bubble column in lunar- and Mars-based operations would be lower than terrestrial designs by factors of 0.64 and 0.79 respectively. The reduced gravity columns would have greater cross-sectional areas, however, by factors of 2.4 and 1.6 for lunar and Martian settings. Similar results were obtained for spray towers. In contract, packed column height was found to be nearly independent of gravity.

  4. Effect of impeller geometry on gas-liquid mass transfer coefficients in filamentous suspensions.

    PubMed

    Dronawat, S N; Svihla, C K; Hanley, T R

    1997-01-01

    Volumetric gas-liquid mass transfer coefficients were measured in suspensions of cellulose fibers with concentrations ranging from 0 to 20 g/L. The mass transfer coefficients were measured using the dynamic method. Results are presented for three different combinations of impellers at a variety of gassing rates and agitation speeds. Rheological properties of the cellulose fibers were also measured using the impeller viscometer method. Tests were conducted in a 20 L stirred-tank fermentor and in 65 L tank with a height to diameter ratio of 3:1. Power consumption was measured in both vessels. At low agitation rates, two Rushton turbines gave 20% better performance than the Rushton and hydrofoil combination and 40% better performance than the Rushton and propeller combination for oxygen transfer. At higher agitation rates, the Rushton and hydrofoil combination gave 14 and 25% better performance for oxygen transfer than two Rushton turbines and the Rushton and hydrofoil combination, respectively.

  5. Finite-time thermodynamics and the gas-liquid phase transition

    NASA Astrophysics Data System (ADS)

    Santoro, M.; Schön, J. C.; Jansen, M.

    2007-12-01

    In this paper, we study the application of the concept of finite-time thermodynamics to first-order phase transitions. As an example, we investigate the transition from the gaseous to the liquid state by modeling the liquification of the gas in a finite time. In particular, we introduce, state, and solve an optimal control problem in which we aim at achieving the gas-liquid first-order phase transition through supersaturation within a fixed time in an optimal fashion, in the sense that the work required to supersaturate the gas, called excess work, is minimized by controlling the appropriate thermodynamic parameters. The resulting set of coupled nonlinear differential equations is then solved for three systems, nitrogen N2 , oxygen O2 , and water vapor H2O .

  6. Gas-liquid chromatographic determination of kepone in field-collected avian tissues and eggs

    USGS Publications Warehouse

    Stafford, C.J.; Reichel, W.L.; Swineford, D.M.; Prouty, R.M.; Gay, M.L.

    1978-01-01

    A procedure is described for determining Kepone (decachlorooctahydro-1,3,4-metheno-2H-cyclobuta [cd] pentalene-2-one) residues in avian egg, liver, and tissue. Samples were extracted with benzene-isopropanol, and the extract was cleaned up with fuming H2SO4-concentrated H2SO4. Kepone was separated from organochlorine pesticides and polychlorinated biphenyls on a Florisil column and analyzed by electron capture gas-liquid chromatography (GLC). The average recovery from spiked tissues was 86%. The analyses performed on 14 bald eagle carcasses and livers, 3 bald eagle eggs, and 14 osprey eggs show measurable levels which indicate that Kepone accumulates in the tissues of fish-eating birds. Residues were confirmed by GLC-mass spectrometry.

  7. Computer modelling of the surface tension of the gas-liquid and liquid-liquid interface.

    PubMed

    Ghoufi, Aziz; Malfreyt, Patrice; Tildesley, Dominic J

    2016-03-07

    This review presents the state of the art in molecular simulations of interfacial systems and of the calculation of the surface tension from the underlying intermolecular potential. We provide a short account of different methodological factors (size-effects, truncation procedures, long-range corrections and potential models) that can affect the results of the simulations. Accurate calculations are presented for the calculation of the surface tension as a function of the temperature, pressure and composition by considering the planar gas-liquid interface of a range of molecular fluids. In particular, we consider the challenging problems of reproducing the interfacial tension of salt solutions as a function of the salt molality; the simulations of spherical interfaces including the calculation of the sign and size of the Tolman length for a spherical droplet; the use of coarse-grained models in the calculation of the interfacial tension of liquid-liquid surfaces and the mesoscopic simulations of oil-water-surfactant interfacial systems.

  8. Convergence rates to stationary solutions of a gas-liquid model with external forces

    NASA Astrophysics Data System (ADS)

    Fan, Long; Liu, Qingqing; Zhu, Changjiang

    2012-10-01

    In this paper, we study the asymptotic behaviour of solutions to a gas-liquid model with external forces. Under some suitable assumptions on the initial data, if γ > 1 and \\theta\\in(0,\\frac{\\gamma}{2}]\\cap(0,\\gamma-1]\\cap(0,1-\\alpha\\gamma] , we prove the weak solution (cQ (x, t), u(x, t)) behaviour asymptotically to the stationary one by adapting and modifying the technique of weighted estimates. In addition, if \\theta\\in(0,\\frac{\\gamma}{2}]\\cap(0,\\gamma-1)\\cap(0,1-\\alpha\\gamma] , following the same idea used in Zhang and Fang (2006 Arch. Ration. Mech. Anal. 182 223-53), we estimate the stabilization rate of the solution as time tends to infinity in the sense of L∞ norm.

  9. Effects of cyclone diameter on performance of 1D3D cyclones: Cut point and slope

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cyclones are a commonly used air pollution abatement device for separating particulate matter (PM) from air streams in industrial processes. Several mathematical models have been proposed to predict the performance of cyclones, as cyclone diameter varies. The objective of this research was to determ...

  10. Effects of cyclone diameter on performance of 1D3D cyclones: Cut point and slope

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cyclones are a commonly used air pollution abatement device for separating particulate matter (PM) from air streams in industrial processes. Several mathematical models have been proposed to predict the cut point of cyclones as cyclone diameter varies. The objective of this research was to determine...

  11. The inactivation of Chlorella spp. with dielectric barrier discharge in gas-liquid mixture

    NASA Astrophysics Data System (ADS)

    Song, Dan; Sun, Bing; Zhu, Xiaomei; Yan, Zhiyu; Liu, Hui; Liu, Yongjun

    2013-03-01

    The inactivation of Chlorella spp. with high voltage and frequency pulsed dielectric barrier discharge in hybrid gas-liquid reactor with a suspension electrode was studied experimentally. In the hybrid gas-liquid reactor, a steel plate was used as high voltage electrode while a quartz plate as a dielectric layer, another steel plate placing in the aqueous solution worked as a whole ground electrode. A suspension electrode is installed near the surface of solution between high voltage and ground electrode to make the dielectric barrier discharge uniform and stable, the discharge gap was between the quartz plate and the surface of the water. The effect of peak voltage, treatment time, the initial concentration of Chlorella spp. and conductivity of solution on the inactivation rate of Chlorella spp. was investigated, and the inactivation mechanism of Chlorella spp. preliminarily was studied. Utilizing this system inactivation of Chlorella spp., the inactivation rate increased with increasing of peak voltage, treatment time and electric conductivity. It was found that the inactivation rate of Chlorella spp. arrived at 100% when the initial concentration was 4 × 106 cells mL-1, and the optimum operation condition required a peak voltage of 20 kV, a treatment time of 10 min and a frequency of 7 kHz. Though the increasing of initial concentration of the Chlorella spp. contributed to the addition of interaction probability between the Chlorella spp. and O3, H2O2, high-energy electrons, UV radiation and other active substances, the total inactivation number raise, but the inactivation rate of the Chlorella spp. decreased.

  12. Idealised simulations of sting jet cyclones

    NASA Astrophysics Data System (ADS)

    Baker, Laura; Gray, Suzanne; Clark, Peter

    2010-05-01

    Extratropical cyclones often produce strong surface winds, mostly associated with low-level jets along the warm and cold fronts. Some severe extratropical cyclones have been found to produce an additional area of localised strong, and potentially very damaging, surface winds during a certain part of their development. These strong winds are associated with air that originates within the cloud head, exiting at the tip of the cloud head and descending rapidly from there to the surface. This rapidly descending air associated with the strong surface winds is known as a sting jet. Previous published work on sting jets has been limited to analyses of only a small number of case studies of observed sting jet cyclones, so a study of idealised sting jet cyclones, rather than specific cases, will be useful in determining the important features and mechanisms that lead to sting jets. This work focuses on an idealised simulation of a cyclone with a sting jet using a periodic channel configuration of the idealised nonhydrostatic Met Office Unified Model. The idealised cyclone simulation is based on baroclinic lifecycle simulations run at sufficiently high resolution for a sting jet to be generated. An analysis of the idealised cyclone and a comparison of the idealised cyclone with case studies of observed sting jet cyclones will be presented.

  13. Tips for selecting highly efficient cyclones

    SciTech Connect

    Amrein, D.L.

    1995-05-01

    Cyclone dust collectors have been used--and misused--all over the world for more than 100 years. One reason for the misuse is a common perception among users that all cyclones are created equal--that is, as long as a cyclone resembles a cylinder with an attached cone, it will do its job. However, to maximize separation efficiency in a specific application requires a precise cyclone design, engineered to exact fit many possible variables. A well-designed cyclone, for instance, can achieve efficiencies as high s 99.9+% when operated properly within the envelope of its specifications. Nonetheless, cyclones are often used only as first-stage filters for performing crude separations, with final collections being carried out by more-costly baghouses and scrubbers. Compared with baghouses and scrubbers, cyclones have two important considerations in their favor. One, they are almost invariably safer--in terms of the potential for generating fires and explosions--than fabric filters. Second, cyclones have lower maintenance costs since there are no filter media to replace. The paper discusses the operation, design, and troubleshooting of cyclones.

  14. Cup Cylindrical Waveguide Antenna

    NASA Technical Reports Server (NTRS)

    Acosta, Roberto J.; Darby, William G.; Kory, Carol L.; Lambert, Kevin M.; Breen, Daniel P.

    2008-01-01

    The cup cylindrical waveguide antenna (CCWA) is a short backfire microwave antenna capable of simultaneously supporting the transmission or reception of two distinct signals having opposite circular polarizations. Short backfire antennas are widely used in mobile/satellite communications, tracking, telemetry, and wireless local area networks because of their compactness and excellent radiation characteristics. A typical prior short backfire antenna contains a half-wavelength dipole excitation element for linear polarization or crossed half-wavelength dipole elements for circular polarization. In order to achieve simultaneous dual circular polarization, it would be necessary to integrate, into the antenna feed structure, a network of hybrid components, which would introduce significant losses. The CCWA embodies an alternate approach that entails relatively low losses and affords the additional advantage of compactness. The CCWA includes a circular cylindrical cup, a circular disk subreflector, and a circular waveguide that serves as the excitation element. The components that make it possible to obtain simultaneous dual circular polarization are integrated into the circular waveguide. These components are a sixpost polarizer and an orthomode transducer (OMT) with two orthogonal coaxial ports. The overall length of the OMT and polarizer (for the nominal middle design frequency of 2.25 GHz) is about 11 in. (approximately equal to 28 cm), whereas the length of a commercially available OMT and polarizer for the same frequency is about 32 in. (approximately equal to 81 cm).

  15. Cylindrical holographic radar camera

    NASA Astrophysics Data System (ADS)

    McMakin, Douglas L.; Sheen, David M.; Hall, Thomas E.; Severtsen, Ronald H.

    1998-12-01

    A novel personnel surveillance system has been developed to rapidly obtain 360 degree, full-body images of humans for the detection and identification of concealed threats. Detectable threats include weapons fabricated with metal, plastic, and ceramic, as well as explosive solids and liquids. This new system uses a cylindrical mechanical scanner to move a seven-foot, 384 element, Ka band (26 - 30 GHz) array circumferentially around a person in four to seven seconds. Low power millimeter-waves, which are nonionizing and not harmful to humans, are employed because they readily penetrate clothing barriers and reflect from concealed threats. The reflected waves provide information that is reconstructed into 3-D cylindrical holographic images with high-speed, digital signal processing (DSP) boards. This system is capable of displaying in an animation format eight, sixteen, thirty-two or sixty-four image frames at various aspect angles around the person under surveillance. This new prototype surveillance system is operational and is presently under laboratory testing and evaluation.

  16. Effects of temperature on the location of the gas-liquid interface in a PEM fuel cell

    NASA Astrophysics Data System (ADS)

    Lee, Chun-I.; Chu, Hsin-Sen

    The objective of this study is to investigate the location of the gas-liquid interface at various temperatures in a polymer electrolyte membrane fuel cell under non-isothermal conditions. A mathematical model, coupled with the electrochemical process, two-phase flows, species transfer, and heat transfer is employed. A finite volume-based CFD approach is applied to investigate the species transport behavior in a fuel cell. The effects of two model parameters, namely cell temperature (T cell) and humidification temperature (T h), on the gas-liquid interface and cell performance are presented. Simulation results indicate that variations of these two parameters influence the location of the gas-liquid interface, the cell performance, and the distribution of liquid water saturation. At lower cell temperatures, the gas-liquid interface moves toward the inlet port of the channel when the humidification temperature is greater than the cell temperature. Therefore, the cell performance decreases as the liquid water clogs the passage for the transport of oxygen. Furthermore, these two factors are closely related to the membrane temperature distribution. Obvious variations in magnitude are seen at a cell temperature of 323 K and a humidification temperature of 343 K.

  17. 40 CFR Table Mm-1 to Subpart Mm of... - Default Factors for Petroleum Products and Natural Gas Liquids 1 2

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Default Factors for Petroleum Products... Suppliers of Petroleum Products Pt. 98, Subpt. MM, Table MM-1 Table MM-1 to Subpart MM of Part 98—Default Factors for Petroleum Products and Natural Gas Liquids 1 2 Products Column A: density(metric...

  18. 40 CFR Table Mm-1 to Subpart Mm of... - Default Factors for Petroleum Products and Natural Gas Liquids 1 2

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Default Factors for Petroleum Products... Suppliers of Petroleum Products Pt. 98, Subpt. MM, Table MM-1 Table MM-1 to Subpart MM of Part 98—Default Factors for Petroleum Products and Natural Gas Liquids 1 2 Products Column A: density(metric...

  19. 40 CFR Table Mm-1 to Subpart Mm of... - Default Factors for Petroleum Products and Natural Gas Liquids 1 2

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Default Factors for Petroleum Products... Suppliers of Petroleum Products Pt. 98, Subpt. MM, Table MM-1 Table MM-1 to Subpart MM of Part 98—Default Factors for Petroleum Products and Natural Gas Liquids 1 2 Products Column A: density(metric...

  20. 40 CFR Table Mm-1 to Subpart Mm of... - Default Factors for Petroleum Products and Natural Gas Liquids 1 2

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Default Factors for Petroleum Products... Suppliers of Petroleum Products Pt. 98, Subpt. MM, Table MM-1 Table MM-1 to Subpart MM of Part 98—Default Factors for Petroleum Products and Natural Gas Liquids 1 2 Products Column A: density(metric...

  1. Working process study of a novel scroll type multiphase pump for the transportation of gas-liquid mixtures

    NASA Astrophysics Data System (ADS)

    Wang, J.; Zha, H. B.; Zhang, X. H.; Zhang, D. H.

    2012-11-01

    A novel scroll type multiphase pump was proposed to transport gas-liquid two-phase mixture. There is a pressure unloading gap from compression chambers to the discharge port by constructing scroll wrap profile with variational meshing clearance in this scroll multiphase pump. In the working process when the volume of working chamber decreases, the pressure of gas-liquid mixtures increases gradually, at the same time small amounts of gas-liquid mixture are pushed to the discharge port from compression chambers through the pressure unloading gap. Therefore, this multiphase pump has an advantage of unloading pressure method automatically, and the frequently problem of liquid impacting in volume multiphase pump is solved. The safety and reliability of volumetric multiphase pump are improved, and the scope of multiphase pump of the gas-liquid ratio is expanded. The working process and the performance characteristics of scroll multiphase pump were analyzed too, and the generation method of scroll wrap profile with variational meshing clearance was investigated. The equations of the profile were obtained, and the changing principle of the working volume and the meshing clearance were analyzed. The geometric theory of scroll multiphase pump was formed. All of that lay the theoretical foundation for engineering design of this novel scroll.

  2. DMS cyclone separation processes for optimization of plastic wastes recycling and their implications.

    PubMed

    Gent, Malcolm Richard; Menendez, Mario; Toraño, Javier; Torno, Susana

    2011-06-01

    It is demonstrated that substantial reductions in plastics presently disposed of in landfills can be achieved by cyclone density media separation (DMS). In comparison with the size fraction of plastics presently processed by industrial density separations (generally 6.4 to 9.5 mm), cyclone DMS methods are demonstrated to effectively process a substantially greater range of particle sizes (from 0.5 up to 120 mm). The purities of plastic products and recoveries obtained with a single stage separation using a cylindrical cyclone are shown to attain virtually 100% purity and recoveries >99% for high-density fractions and >98% purity and recoveries were obtained for low-density products. Four alternative schemas of multi-stage separations are presented and analyzed as proposed methods to obtain total low- and high-density plastics fraction recoveries while maintaining near 100% purities. The results of preliminary tests of two of these show that the potential for processing product purities and recoveries >99.98% of both density fractions are indicated. A preliminary economic comparison of capital costs of DMS systems suggests cyclone DMS methods to be comparable with other DMS processes even if the high volume capacity for recycling operations of these is not optimized.

  3. Good field practice helps cyclones do job

    SciTech Connect

    White, D.L.

    1982-11-08

    This article examines use of hydrocyclones in mud equipment operations involving desilters, desanders, shale shakers and degassers for unweighted mud. Presents a diagram of ideal equipment placement, a table sizing cyclones considering mud guns, and a graph sizing cyclones to a drilling rig. Suggests checklists for troubleshooting and operation based on hydrocyclone capacity, plugging, head and flow rates, mud weight and viscosity.

  4. Objective identification of cyclones in GCM simulations

    SciTech Connect

    Koenig, W.; Sielmann, F. ); Sausen, R. )

    1993-12-01

    An objective routine for identifying the individual cyclones has been developed. The procedure was designed with the aim to keep the input expenditure low. The method ensures a complete collection of cyclones and an exclusion of short time fluctuations attributed to numerical effects. The cyclones are identified as relative minima of the geopotential height field in 1000 hPa. The initial stages of the cyclones are found by locating relative maxima in the 850-hPa vorticity field. Further on the temporal development of the extrema is taken into consideration. An individual cyclone is regarded only if it exists for at least 24 h and if it attains a mature stage at least once, where a certain margin of the geopotential gradient to the surroundings is exceeded. The identification routine is applied to simulations with the Hamburg general circulation model ECHAM in T21 resolution. Also, cyclone tracks based on ECMWF analyses are evaluated, to which the model results are compared. The effect of different climate conditions, for example, global warming, on cyclone frequency and track location is investigated. It is found that a warmer SST distribution leads to a slight reduction of cyclone frequency in the Southern Hemisphere in fall (March, April, May) and winter (June, July, August); elsewhere the differences are not significant. 25 refs., 9 figs., 1 tab.

  5. GPM Rain Rates in Tropical Cyclone Pam

    NASA Video Gallery

    NASA-JAXA's GPM Satellite Close-up of Cyclone Pam's Rainfall NASA-JAXA's GPM core satellite captured rain rates in Tropical Cyclone Pam at 03:51 UTC (2:51 p.m. local time) on March 14, 2015. Heavie...

  6. Predictability of Sheared Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Zhang, F.; Tao, D.

    2015-12-01

    Predictability of the formation, rapid intensification and eyewall replacement of sheared tropical cyclones (TCs) are explored through a series of convection-permitting ensemble simulations using the Weather Research and Forecasting (WRF) model with different environmental vertical wind shear, sea-surface temperature (SST), and ambient moisture conditions. It is found that the intrinsic predictability of the RI onset time is more limited with increasing shear magnitude until the shear magnitude is large enough to prevent the TC formation. Based on ensemble sensitivity and correlation analysis, the RI onset timing within one set is largely related to the vortex tilt magnitude, the diabatic heating distribution and the strength of the primary vortex circulation. Systematic differences amongst the ensemble members begin to arise right after the initial burst of moist convection associated with the incipient vortex. This difference from the randomness inherent in moist convection in terms of both location and intensity first changes the TC vortex structure subtly and then leads to the deviations in system scales and eventually in the development (and precession) of the TC. On average, a higher SST has a positive effect on the TC formation and reduces the uncertainty of development under all shear conditions, while a drier environment has a negative impact on the TCs development and either broadens the ensemble spread of RI onset time or prevents the storm from forming when the shear-induced tilt is large. Nevertheless, the uncertainty in environmental shear magnitudes may dominate over the effect of randomness in moist convection in terms of TC formation and predictability. A byproduct of tropical cyclones under vertical wind shear is the secondary eyewall formation (SEF). It is found that the eyewall formation is more often observed in TCs with moderate to high shear, which was inherently more unpredictable. The inward contraction/axisymmeterization of shear

  7. Cyclone Center: Insights on Historical Tropical Cyclones from Citizen Volunteers

    NASA Astrophysics Data System (ADS)

    Thorne, P.; Hennon, C. C.; Knapp, K. R.; Schreck, C. J., III; Stevens, S. E.; Kossin, J. P.; Rennie, J.; Hennon, P. A.; Kruk, M. C.

    2015-12-01

    The cyclonecenter.org project started in fall 2012 and has been collecting citizen scientist volunteer tropical cyclone intensity estimates ever since. The project is hosted by the Citizen Science Alliance (zooniverse) and the platform is supported by a range of scientists. We have over 30 years of satellite imagery of tropical cyclones but the analysis to date has been done on an ocean-basin by ocean-basin basis and worse still practices have changed over time. We therefore do not, presently, have a homogeneous record relevant for discerning climatic changes. Automated techniques can classify many of the images but have a propensity to be challenged during storm transitions. The problem is fundamentally one where many pairs of eyes are invaluable as there is no substitute for human eyes in discerning patterns. Each image is classified by ten unique users before it is retired. This provides a unique insight into the uncertainty inherent in classification. In the three years of the project much useful data has accrued. This presentation shall highlight some of the results and analyses to date and touch on insights as to what has worked and what perhaps has not worked so well. There are still many images left to complete so its far from too late to jump over to www.cyclonecenter.org and help out.

  8. Cylindrical geometry hall thruster

    DOEpatents

    Raitses, Yevgeny; Fisch, Nathaniel J.

    2002-01-01

    An apparatus and method for thrusting plasma, utilizing a Hall thruster with a cylindrical geometry, wherein ions are accelerated in substantially the axial direction. The apparatus is suitable for operation at low power. It employs small size thruster components, including a ceramic channel, with the center pole piece of the conventional annular design thruster eliminated or greatly reduced. Efficient operation is accomplished through magnetic fields with a substantial radial component. The propellant gas is ionized at an optimal location in the thruster. A further improvement is accomplished by segmented electrodes, which produce localized voltage drops within the thruster at optimally prescribed locations. The apparatus differs from a conventional Hall thruster, which has an annular geometry, not well suited to scaling to small size, because the small size for an annular design has a great deal of surface area relative to the volume.

  9. HOMOLOGOUS CYCLONES IN THE QUIET SUN

    SciTech Connect

    Yu, Xinting; Zhang, Jun; Li, Ting; Zhang, Yuzong; Yang, Shuhong E-mail: zjun@nao.cas.cn E-mail: yuzong@nao.cas.cn

    2014-02-20

    Through observations with the Solar Dynamics Observatory Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager, we tracked one rotating network magnetic field (RNF) near the solar equator. It lasted for more than 100 hr, from 2013 February 23 to 28. During its evolution, three cyclones were found to be rooted in this structure. Each cyclone event lasted for about 8 to 10 hr. While near the polar region, another RNF was investigated. It lasted for a shorter time (∼70 hr), from 2013 July 7 to 9. There were two cyclones rooted in the RNF and each lasted for 8 and 11 hr, respectively. For the two given examples, the cyclones have a similar dynamic evolution, and thus we put forward a new term: homologous cyclones. The detected brightening in AIA 171 Å maps indicates the release of energy, which is potentially available to heat the corona.

  10. Reconstruction and use of battery cyclones

    SciTech Connect

    Nazarov, V.D.; Zabrodnii, I.V.; Kolomoiskii, V.G.; Dodik, G.A.; Afanas'ev, O.K.; Gusarov, N.I.; Strakhov, A.B.

    1988-03-01

    The authors discuss a sinter plant where reliable and stable operation of its modernized cyclones has made it possible to improve the performance of the gas-cleaning system as a whole, while increasing the life of the exhauster rotors to one year and improving the performance indices of the sintering machines. The battery cyclones were modernized by replacing the existing elements with consolidated cyclone elements and the elements were provided with four-pipe semihelical swirlers. The elements were made of ordinary steel pipes 530 and 273 mm in diameter. During manufacture and installation of the cyclone elements, special attention was given to the coaxiality of the housings and the outlet pipes of the elements, the hermeticity and density of the welds, the dimensional accuracy of the elements, the perpendicularity of the bearing flange and outlet-pipe axis, and the finish of the inside surfaces of the cyclone elements.

  11. Drop tower experiment for performance evaluation of gas-liquid equilibrium thruster for small spacecraft

    NASA Astrophysics Data System (ADS)

    Motooka, Norizumi; Yamamoto, Takayuki; Mori, Osamu; Okano, Yoshinobu; Kishino, Yoshihiro; Kawaguchi, Junichiro

    JAXA/ISAS is developing the gas-liquid equilibrium thruster for a small spacecraft. In small spacecrafts, the thruster system must be simple and its weight must be light. This thruster system uses HFC-134a (1,1,1,2-tetrafluoroethane) , a kind of liquefied gas, as propellant because of its harmlessness and ease of handling. And this thruster stores propellant as liquid in the tank and ejects propellant as gas using the gas-liquid equilibrium pressure to produce thrust, so the propellant tank only needs to resist the vapor pressure of propellant. In this thruster system, the porous metal is also equipped in the tank for the following performance advantages: (1) liquid fuel retention: The porous metal reduces sloshing problems which cause bad effects on spacecraft attitude by retaining liquid propellant inside the porous metal: (2) vapor-liquid separation: The porous metal also helps propellant separate gas from liquid by advancing propellant vaporization on its large surface area and retaining liquid propellant using its surface tension. In last autumn, we carried out the experiment to evaluate these two advantages of porous metal under micro gravity condition using 50 meters drop tower in Hokkaido, Japan. The system of this experiment divides into two different systems. The first one evaluates liquid propellant retention performance by adding disturbance to liquid propellant absorbed in porous metal. The disturbance is centrifugal force and angular acceleration worked on the liquid propellant by rotating propellant tank controlled by motor. A high speed camera records the behavior of the liquid propellant. The other one evaluates the ability of gas-liquid separation on the case of propellant ejection. In this evaluation, the parameters are full filling porous metal or some ullage in the tank, nozzle diameters and the filling ratio of liquid propellant in the tank. As for (1) liquid fuel retention, in all conducted cases without propellant ejection, liquid propellant

  12. Flow chemistry: intelligent processing of gas-liquid transformations using a tube-in-tube reactor.

    PubMed

    Brzozowski, Martin; O'Brien, Matthew; Ley, Steven V; Polyzos, Anastasios

    2015-02-17

    CONSPECTUS: The previous decade has witnessed the expeditious uptake of flow chemistry techniques in modern synthesis laboratories, and flow-based chemistry is poised to significantly impact our approach to chemical preparation. The advantages of moving from classical batch synthesis to flow mode, in order to address the limitations of traditional approaches, particularly within the context of organic synthesis are now well established. Flow chemistry methodology has led to measurable improvements in safety and reduced energy consumption and has enabled the expansion of available reaction conditions. Contributions from our own laboratories have focused on the establishment of flow chemistry methods to address challenges associated with the assembly of complex targets through the development of multistep methods employing supported reagents and in-line monitoring of reaction intermediates to ensure the delivery of high quality target compounds. Recently, flow chemistry approaches have addressed the challenges associated with reactions utilizing reactive gases in classical batch synthesis. The small volumes of microreactors ameliorate the hazards of high-pressure gas reactions and enable improved mixing with the liquid phase. Established strategies for gas-liquid reactions in flow have relied on plug-flow (or segmented flow) regimes in which the gas plugs are introduced to a liquid stream and dissolution of gas relies on interfacial contact of the gas bubble with the liquid phase. This approach confers limited control over gas concentration within the liquid phase and is unsuitable for multistep methods requiring heterogeneous catalysis or solid supported reagents. We have identified the use of a gas-permeable fluoropolymer, Teflon AF-2400, as a simple method of achieving efficient gas-liquid contact to afford homogeneous solutions of reactive gases in flow. The membrane permits the transport of a wide range of gases with significant control of the stoichiometry of

  13. Cylindrical quasi-Gaussian beams.

    PubMed

    Mitri, F G

    2013-11-15

    Making use of the complex-source-point method in cylindrical coordinates, an exact solution representing a cylindrical quasi-Gaussian beam of arbitrary waist w(0) satisfying both the Helmholtz and Maxwell's equations is introduced. The Cartesian components of the electromagnetic field are derived stemming from different polarizations of the magnetic and electric vector potentials based on Maxwell's vectorial equations and Lorenz's gauge condition, without any approximations. Computations illustrate the theory for tightly focused and quasi-collimated cylindrical beams. The results are particularly useful in beam-forming design using high-aperture or collimated cylindrical laser beams in imaging microscopy, particle manipulation, optical tweezers, and the study of scattering, radiation forces, and torque on cylindrical structures.

  14. LCSs in tropical cyclone genesis

    NASA Astrophysics Data System (ADS)

    Rutherford, B.; Montgomery, M. T.

    2011-12-01

    The formation of tropical cyclones in the Atlantic most often occurs at the intersection of the wave trough axis of a westward propagating African easterly wave and the wave critical latitude. Viewed in a moving reference frame with the wave, a cat's eye region of cyclonic recirculation can be seen in streamlines prior to genesis. The cat's eye recirculation region has little strain deformation and its center serves as the focal point for aggregation of convectively generated vertical vorticity. Air inside the cat's eye is repeatedly moistened by convection and is protected from the lateral intrusion of dry air. Since the flow is inherently time-dependent, we contrast the time-dependent structures with Eulerian structures of the wave-relative frame. Time-dependence complicates the kinematic structure of the recirculation region as air masses from the outer environment are allowed to interact with the interior of the cat's eye. LCSs show different boundaries of the cat's eye than the streamlines in the wave-relative frame. These LCSs are particularly important for showing the pathways of air masses that interact with the developing vortex, as moist air promotes development by supporting deep convection, while interaction with dry air impedes development. We primarily use FTLEs to locate the LCSs, and show the role of LCSs in both developing and non-developing storms. In addition, we discuss how the vertical coherence of LCSs is important for resisting the effects of vertical wind shear.

  15. Cyclone Center: Using Crowdsourcing to Determine Tropical Cyclone Intensity (Invited)

    NASA Astrophysics Data System (ADS)

    Hennon, C. C.; Knapp, K. R.; Schreck, C. J.; Stevens, S. E.; Kossin, J. P.

    2013-12-01

    The strength of tropical cyclones (TCs) is traditionally determined using the sustained maximum wind speed. Because TCs develop and spend most of their lifetime over tropical oceans, it is rare to directly observe a storm well enough to determine its strength accurately. The Dvorak technique was developed in the 1970s and 1980s to address this problem. By determining a number of cloud and structural characteristics from satellite images, a forecaster could now arrive at a reasonable maximum sustained wind without direct observations. However, the Dvorak technique by nature is subjective and it has been shown that trained experts frequently disagree on storm intensities. Furthermore, the application of the rules and constraints of the process has diverged with time across different forecast centers. This has led in several cases to severe disagreements in storm intensities when two or more forecast centers track the same TC. The accumulation of these differences has caused heterogeneous trends in TC intensity to arise at decadal time scales. A global reanalysis of TC intensity is required to resolve these discrepancies, but such an undertaking is unrealistic. Cyclone Center, an Internet crowd sourcing site for TCs, was created to resolve differences in TC intensities and produce a consistent 32-year (1978-2009) record of it. By using a homogeneous satellite dataset (HURSAT) and adapting the Dvorak technique into a set of three or four simple questions, laypersons perform the actions of the expert. User responses are converted into 3-hourly storm intensities. To capitalize on the crowd sourcing approach, at least 10 different users are shown the same image; this allows critical data such as cloud pattern uncertainties and storm metadata (e.g. eye size, center location, cloud pattern) to be collected. Preliminary analyses show that our citizen scientists many times outperform computer classifications in pattern matching and exhibit low bias and mean error when

  16. Research and Design of Thermophysical Gas-Liquid Mixture Parameters in Product Pipelines

    NASA Astrophysics Data System (ADS)

    Dudin, S. M.; Zemenkov, Yu D.; Maier, A. V.; Shabarov, A. B.

    2016-10-01

    Operational problems are hard to overcome because of the temperature and pressure conditions of the hydrocarbon flow in the pipe, as well as the composition of the hydrocarbon system and the geometry of the pipeline. It is known that energy costs to pump a unit mass of RH in the form of gas 2-3 times exceed energy costs to pump a unit mass of RH in the form of liquid. As far as energy conservation during RH transportation is concerned, an important task is development and application of a method to calculate the gas-liquid hydrocarbons flow, and heat and mass transfer in process and trunk pipelines during their design and operation. The authors have developed a calculation method which is used to analyze the hydrodynamic state and composition of the hydrocarbon mixture in each ith section of the pipeline when temperature-pressure and hydraulic conditions change. The developed technique was tested on the hydrocarbon mixture of de-ethanized condensate and oil transported from northern oil and gas condensate fields via the main gas condensate line to the refinery.

  17. Gas-Liquid Two-Phase Flows Through Packed Bed Reactors in Microgravity

    NASA Technical Reports Server (NTRS)

    Motil, Brian J.; Balakotaiah, Vemuri

    2001-01-01

    The simultaneous flow of gas and liquid through a fixed bed of particles occurs in many unit operations of interest to the designers of space-based as well as terrestrial equipment. Examples include separation columns, gas-liquid reactors, humidification, drying, extraction, and leaching. These operations are critical to a wide variety of industries such as petroleum, pharmaceutical, mining, biological, and chemical. NASA recognizes that similar operations will need to be performed in space and on planetary bodies such as Mars if we are to achieve our goals of human exploration and the development of space. The goal of this research is to understand how to apply our current understanding of two-phase fluid flow through fixed-bed reactors to zero- or partial-gravity environments. Previous experiments by NASA have shown that reactors designed to work on Earth do not necessarily function in a similar manner in space. Two experiments, the Water Processor Assembly and the Volatile Removal Assembly have encountered difficulties in predicting and controlling the distribution of the phases (a crucial element in the operation of this type of reactor) as well as the overall pressure drop.

  18. Direct numerical simulation of interfacial wave generation in turbulent gas-liquid flows in horizontal channels

    NASA Astrophysics Data System (ADS)

    Campbell, Bryce; Hendrickson, Kelli; Liu, Yuming; Subramani, Hariprasad

    2014-11-01

    For gas-liquid flows through pipes and channels, a flow regime (referred to as slug flow) may occur when waves form at the interface of a stratified flow and grow until they bridge the pipe diameter trapping large elongated gas bubbles within the liquid. Slug formation is often accompanied by strong nonlinear wave-wave interactions, wave breaking, and gas entrainment. This work numerically investigates the fully nonlinear interfacial evolution of a two-phase density/viscosity stratified flow through a horizontal channel. A Navier-Stokes flow solver coupled with a conservative volume-of-fluid algorithm is use to carry out high resolution three-dimensional simulations of a turbulent gas flowing over laminar (or turbulent) liquid layers. The analysis of such flows over a range of gas and liquid Reynolds numbers permits the characterization of the interfacial stresses and turbulent flow statistics allowing for the development of physics-based models that approximate the coupled interfacial-turbulent interactions and supplement the heuristic models built into existing industrial slug simulators.

  19. A continuous film-recirculable drop gas-liquid equilibration device. Measurement of trace gaseous ammonia

    PubMed

    Genfa; Dasgupta

    2000-07-15

    A miniature gas-liquid equilibrator or a gas collector, intended as a low-volume interface between a soluble gaseous sample and a liquid phase analyzer or between a liquid phase sample and a detector designed for use with gas samples, is described. This paper addresses the application of the device for the measurement of trace atmospheric ammonia. Gas collection occurs solely by diffusive sampling such that aerosol particles are not collected. The device essentially consists of a tube surrounded externally by a jacket. Gas flows through the jacket and contacts a liquid film flowing on the surface of the tube. The flowing film forms a drop at the tube terminus and is aspirated off through the inner bore of the tube. The collected analyte can be (a) directly sent to an analysis system or (b) preconcentrated on a suitable stationary phase; the preconcentrator effluent can be recycled, if desired. With a fluorometric flow injection analysis system harnessed to measure ammonia with such a collector, the limit of detection (LOD, S/N = 3) for a sample drawn for 18 min at 200 mL/min was 4.5 parts per trillion by volume, with the linear range extending up to 30 parts per billion.

  20. Effect of impeller geometry on gas-liquid mass transfer coefficients in filamentous suspensions

    SciTech Connect

    Dronawat, S.N.; Svihla, C.K.; Hanley, T.R.

    1997-12-31

    Volumetric gas-liquid mass transfer coefficients were measured in suspensions of cellulose fibers with concentrations ranging from 0 to 20 g/L. The mass transfer coefficients were measured using the dynamic method. Results are presented for three different combinations of impellers at a variety of gassing rates and agitation speeds. Rheological properties of the cellulose fibers were also measured using the impeller viscometer method. Tests were conducted in a 20 L stirred-tank fermentor and in 65 L tank with a height to diameter ratio of 3:1. Power consumption was measured in both vessels. At low agitation rates, two Rushton turbines gave 20% better performance than the Rushton and hydrofoil combination and 40% better performance than the Rushton and propeller combination for oxygen transfer. At higher agitation rates, the Rushton and hydrofoil combination gave 14 and 25% better performance for oxygen transfer than two Rushton turbines and the Rushton and hydrofoil combination, respectively. 8 refs., 11 figs., 1 tab.

  1. Effects of Gravity on Cocurrent Two-Phase Gas-Liquid Flows Through Packed Columns

    NASA Technical Reports Server (NTRS)

    Motil, Brian J.; Balakotaiah, Vemuri; Kamotani, Yasuhiro

    2001-01-01

    This work presents the experimental results of research on the influence of gravity on flow pattern transitions, pressure drop and flow characteristics for cocurrent gas-liquid two-phase flow through packed columns. The flow pattern transition data indicates that the pulse flow regime exists over a wider range of gas and liquid flow rates under reduced gravity conditions compared to normal gravity cocurrent down-flow. This is illustrated by comparing the flow regime transitions found in reduced gravity with the transitions predicted by Talmor. Next, the effect of gravity on the total pressure drop in a packed column is shown to depend on the flow regime. The difference is roughly equivalent to the liquid static head for bubbly flow but begins to decrease at the onset of pulse flow. As the spray flow regime is approached by increasing the gas to liquid ratio, the effect of gravity on pressure drop becomes negligible. Finally, gravity tends to suppress the amplitude of each pressure pulse. An example of this phenomenon is presented.

  2. Gas-liquid interfacial plasmas producing reactive species for cell membrane permeabilization

    PubMed Central

    Kaneko, Toshiro; Sasaki, Shota; Takashima, Keisuke; Kanzaki, Makoto

    2017-01-01

    Gas-liquid interfacial atmospheric-pressure plasma jets (GLI-APPJ) are used medically for plasma-induced cell-membrane permeabilization. In an attempt to identify the dominant factors induced by GLI-APPJ responsible for enhancing cell-membrane permeability, the concentration and distribution of plasma-produced reactive species in the gas and liquid phase regions are measured. These reactive species are classified in terms of their life-span: long-lived (e.g., H2O2), short-lived (e.g., O2•−), and extremely-short-lived (e.g., •OH). The concentration of plasma-produced •OHaq in the liquid phase region decreases with an increase in solution thickness (<1 mm), and plasma-induced cell-membrane permeabilization is found to decay markedly as the thickness of the solution increases. Furthermore, the horizontally center-localized distribution of •OHaq, resulting from the center-peaked distribution of •OH in the gas phase region, corresponds with the distribution of the permeabilized cells upon APPJ irradiation, whereas the overall plasma-produced oxidizing species such as H2O2aq in solution exhibit a doughnut-shaped horizontal distribution. These results suggest that •OHaq is likely one of the dominant factors responsible for plasma-induced cell-membrane permeabilization. PMID:28163376

  3. Comparison of electrical and optical characteristics in gas-phase and gas-liquid phase discharges

    NASA Astrophysics Data System (ADS)

    Qazi, H. I. A.; Nie, Qiu-Yue; Li, He-Ping; Zhang, Xiao-Fei; Bao, Cheng-Yu

    2015-12-01

    This paper presents an AC-excited argon discharge generated using a gas-liquid (two-phase) hybrid plasma reactor, which mainly consists of a powered needle electrode enclosed in a conical quartz tube and grounded deionized water electrode. The discharges in the gas-phase, as well as in the two-phase, exhibit two discharge modes, i.e., the low current glow-like diffuse mode and the high current streamer-like constrict mode, with a mode transition, which exhibits a negative resistance of the discharges. The optical emission spectral analysis shows that the stronger diffusion of the water vapor into the discharge region in the two-phase discharges boosts up the generation of OH (A-X) radicals, and consequently, leads to a higher rotational temperature in the water-phase plasma plume than that of the gas-phase discharges. Both the increase of the power input and the decrease of the argon flow rate result in the increase of the rotational temperature in the plasma plume of the water-phase discharge. The stable two-phase discharges with a long plasma plume in the water-phase under a low power input and gas flow rate may show a promising prospect for the degradation of organic pollutants, e.g., printing and dyeing wastewater, in the field of environmental protection.

  4. Open, microfluidic flow cell for studies of interfacial processes at gas-liquid interfaces.

    PubMed

    Hoang, Khanh C; Malakhov, Dmitry; Momsen, William E; Brockman, Howard L

    2006-03-01

    Interfacial processes involving peripheral proteins depend on the composition and packing density of the interfacial lipid molecules. As a biological membrane model, lipid monolayers at the gas-liquid interface allow independent control of these parameters. However, measuring protein adsorption to monolayers has been difficult. To aid in this and other studies of the interfacial processes, we have developed an open, microfluidic flow cell with which surface physical properties can be controlled and monitored in well-defined lipid monolayers while varying aqueous-phase composition. Using this apparatus, we implement a recently described fluorescence method (Momsen, W. E.; Mizuno, N. K.; Lowe, M. E.; Brockman, H. L. Anal. Biochem. 2005, 346, 139-49) to characterize the adsorption/desorption of glucagon to 1,2-dioleoyl-sn-glycerol monolayers at 27 mN/m. Analysis of the data gives reasonable and self-consistent results for kinetic and thermodynamic constants. Varying the packing density of 1,2-dioleoyl-sn-glycerol does not alter the extent of glucagon adsorption, but comparable measurements with 1-steaoryl-2-oleoyl-sn-glycero-3-phosphocholine show a critical dependence. Because it allows a high degree of control of both lipid monolayer properties and aqueous-phase composition, this microfluidic flow cell should find wide applicability in many areas of research into interfacial processes.

  5. Rapid nondestructive spectrometric measurement of temperature-dependent gas-liquid solubility equilibria.

    PubMed

    Ma, Jian; Dasgupta, Purnendu K; Yang, Bingcheng

    2011-02-01

    Gas-liquid solubility equilibria (Henry's Law behavior) are of basic interest to many different areas. Temperature-dependent aqueous solubilities of various organic compounds are of fundamental importance in many branches of environmental science. In a number of situations, the gas/dissolved solute of interest has characteristic spectroscopic absorption that is distinct from that of the solvent. For such cases, we report facile nondestructive rapid measurement of the temperature-dependent Henry's law constant (K(H)) in a static sealed spectrometric cell. Combined with a special cell design, multiwavelength measurement permits a large range of K(H) to be spanned. It is possible to derive the K(H) values from the absorbance measured in the gas phase only, the liquid phase only (preferred), and both phases. Underlying principles are developed, and all three approaches are illustrated for a solute like acetone in water. A thermostatic spectrophotometer cell compartment, widely used and available, facilitates rapid temperature changes and allows rapid temperature-dependent equilibrium measurements. Applicability is shown for both acetone and methyl isobutyl ketone. Very little sample is required for the measurement; the K(H) for 4-hydroxynonenal, a marker for oxidative stress, is measured to be 56.9 ± 2.6 M/atm (n = 3) at 37.4 °C with 1 mg of the material available.

  6. Comparison of electrical and optical characteristics in gas-phase and gas-liquid phase discharges

    SciTech Connect

    Qazi, H. I. A.; Li, He-Ping Zhang, Xiao-Fei; Bao, Cheng-Yu; Nie, Qiu-Yue

    2015-12-15

    This paper presents an AC-excited argon discharge generated using a gas-liquid (two-phase) hybrid plasma reactor, which mainly consists of a powered needle electrode enclosed in a conical quartz tube and grounded deionized water electrode. The discharges in the gas-phase, as well as in the two-phase, exhibit two discharge modes, i.e., the low current glow-like diffuse mode and the high current streamer-like constrict mode, with a mode transition, which exhibits a negative resistance of the discharges. The optical emission spectral analysis shows that the stronger diffusion of the water vapor into the discharge region in the two-phase discharges boosts up the generation of OH (A–X) radicals, and consequently, leads to a higher rotational temperature in the water-phase plasma plume than that of the gas-phase discharges. Both the increase of the power input and the decrease of the argon flow rate result in the increase of the rotational temperature in the plasma plume of the water-phase discharge. The stable two-phase discharges with a long plasma plume in the water-phase under a low power input and gas flow rate may show a promising prospect for the degradation of organic pollutants, e.g., printing and dyeing wastewater, in the field of environmental protection.

  7. Crystalline Graphdiyne Nanosheets Produced at a Gas/Liquid or Liquid/Liquid Interface.

    PubMed

    Matsuoka, Ryota; Sakamoto, Ryota; Hoshiko, Ken; Sasaki, Sono; Masunaga, Hiroyasu; Nagashio, Kosuke; Nishihara, Hiroshi

    2017-02-15

    Synthetic two-dimensional polymers, or bottom-up nanosheets, are ultrathin polymeric frameworks with in-plane periodicity. They can be synthesized in a direct, bottom-up fashion using atomic, ionic, or molecular components. However, few are based on carbon-carbon bond formation, which means that there is a potential new field of investigation into these fundamentally important chemical bonds. Here, we describe the bottom-up synthesis of all-carbon, π-conjugated graphdiyne nanosheets. A liquid/liquid interfacial protocol involves layering a dichloromethane solution of hexaethynylbenzene on an aqueous layer containing a copper catalyst at room temperature. A multilayer graphdiyne (thickness, 24 nm; domain size, >25 μm) emerges through a successive alkyne-alkyne homocoupling reaction at the interface. A gas/liquid interfacial synthesis is more successful. Sprinkling a very small amount of hexaethynylbenzene in a mixture of dichloromethane and toluene onto the surface of the aqueous phase at room temperature generated single-crystalline graphdiyne nanosheets, which feature regular hexagonal domains, a lower degree of oxygenation, and uniform thickness (3.0 nm) and lateral size (1.5 μm).

  8. Two parametric flow measurement in gas-liquid two-phase flow

    NASA Astrophysics Data System (ADS)

    Chen, Z.; Chen, C.; Xu, Y.; Zhao, Z.

    The importance and current development of two parametric measurement during two-phase flow are briefly reviewed in this paper. Gas-liquid two-phase two parametric metering experiments were conducted by using an oval gear meter and a sharp edged orifice mounted in series in a horizontal pipe. Compressed air and water were used as gas and liquid phases respectively. The correlations, which can be used to predict the total flow rate and volumetric quality of two-phase flow or volumetric flow rate of each phase, have also been proposed in this paper. Comparison of the calculated values of flow rate of each phase from the correlations with the test data showed that the root mean square fractional deviation for gas flow rate is 2.9 percent and for liquid flow rate 4.4 percent. The method proposed in this paper can be used to measure the gas and liquid flow rate in two-phase flow region without having to separate the phases.

  9. Acquisition of void fraction of pulsatile gas-liquid two-phase flow in rectangular channel

    NASA Astrophysics Data System (ADS)

    Zhou, Bao; Liu, Jingxing; Tian, Jingda

    2013-07-01

    Experiment on two-phase pulsatile flow in a narrow rectangular visualization channel was carried out and photographed. Every frame was treated and restored as a black-white binary picture with the threshold of both gray-scale and gray-scale gradient. The gas-liquid interface in the binary pictures can be recognized well, including some very obvious interface, which either cannot be distinguished, or introduce big wrong-recognized area with the gray-scale threshold only. Then after such as `dilate', `erode', `fill', `filter' and so on operating, the binary pictures can reflect the twophase distinction situation in the experimental channel well; The instantaneous average void frictions at the length that the camera covered were calculated by counting the black and white pixels from the pictures. The average void fractions in the whole length of the test section were calculated with an iteration method. The average void fractions in the special length covered by camera and the ones in the whole length of the test section are different. The former shows that the void frictions dramatically frequently change, while the later at steady flow almost stay peace, at pulsatile flow change smoothly.

  10. Can we approach the gas-liquid critical point using slab simulations of two coexisting phases?

    PubMed

    Goujon, Florent; Ghoufi, Aziz; Malfreyt, Patrice; Tildesley, Dominic J

    2016-09-28

    In this paper, we demonstrate that it is possible to approach the gas-liquid critical point of the Lennard-Jones fluid by performing simulations in a slab geometry using a cut-off potential. In the slab simulation geometry, it is essential to apply an accurate tail correction to the potential energy, applied during the course of the simulation, to study the properties of states close to the critical point. Using the Janeček slab-based method developed for two-phase Monte Carlo simulations [J. Janec̆ek, J. Chem. Phys. 131, 6264 (2006)], the coexisting densities and surface tension in the critical region are reported as a function of the cutoff distance in the intermolecular potential. The results obtained using slab simulations are compared with those obtained using grand canonical Monte Carlo simulations of isotropic systems and the finite-size scaling techniques. There is a good agreement between these two approaches. The two-phase simulations can be used in approaching the critical point for temperatures up to 0.97 TC(∗) (T(∗) = 1.26). The critical-point exponents describing the dependence of the density, surface tension, and interfacial thickness on the temperature are calculated near the critical point.

  11. Stage Cylindrical Immersive Display

    NASA Technical Reports Server (NTRS)

    Abramyan, Lucy; Norris, Jeffrey S.; Powell, Mark W.; Mittman, David S.; Shams, Khawaja S.

    2011-01-01

    Panoramic images with a wide field of view intend to provide a better understanding of an environment by placing objects of the environment on one seamless image. However, understanding the sizes and relative positions of the objects in a panorama is not intuitive and prone to errors because the field of view is unnatural to human perception. Scientists are often faced with the difficult task of interpreting the sizes and relative positions of objects in an environment when viewing an image of the environment on computer monitors or prints. A panorama can display an object that appears to be to the right of the viewer when it is, in fact, behind the viewer. This misinterpretation can be very costly, especially when the environment is remote and/or only accessible by unmanned vehicles. A 270 cylindrical display has been developed that surrounds the viewer with carefully calibrated panoramic imagery that correctly engages their natural kinesthetic senses and provides a more accurate awareness of the environment. The cylindrical immersive display offers a more natural window to the environment than a standard cubic CAVE (Cave Automatic Virtual Environment), and the geometry allows multiple collocated users to simultaneously view data and share important decision-making tasks. A CAVE is an immersive virtual reality environment that allows one or more users to absorb themselves in a virtual environment. A common CAVE setup is a room-sized cube where the cube sides act as projection planes. By nature, all cubic CAVEs face a problem with edge matching at edges and corners of the display. Modern immersive displays have found ways to minimize seams by creating very tight edges, and rely on the user to ignore the seam. One significant deficiency of flat-walled CAVEs is that the sense of orientation and perspective within the scene is broken across adjacent walls. On any single wall, parallel lines properly converge at their vanishing point as they should, and the sense of

  12. Exact solutions for laminated composite cylindrical shells in cylindrical bending

    NASA Technical Reports Server (NTRS)

    Yuan, F. G.

    1992-01-01

    Analytic elasticity solutions for laminated composite cylindrical shells under cylindrical bending are presented. The material of the shell is assumed to be general cylindrically anisotropic. Based on the theory of cylindrical anisotropic elasticity, coupled governing partial differential equations are developed. The general expressions for the stresses and displacements in the laminated composite cylinders are discussed. The closed form solutions based on Classical Shell Theory (CST) and Donnell's (1933) theory are also derived for comparison purposes. Three examples illustrate the effect of radius-to-thickness ratio, coupling and stacking sequence. The results show that, in general, CST yields poor stress and displacement distributions for thick-section composite shells, but converges to the exact elasticity solution as the radius-to-thickness ratio increases. It is also shown that Donnell's theory significantly underestimates the stress and displacement response.

  13. Cylindrically symmetric dust spacetime

    NASA Astrophysics Data System (ADS)

    Senovilla, José M. M.

    2000-07-01

    We present an explicit exact solution of Einstein's equations for an inhomogeneous dust universe with cylindrical symmetry. The spacetime is extremely simple but nonetheless it has surprising new features. The universe is `closed' in the sense that the dust expands from a big-bang singularity but recollapses to a big-crunch singularity. In fact, both singularities are connected so that the whole spacetime is `enclosed' within a single singularity of general character. The big-bang is not simultaneous for the dust, and in fact the age of the universe as measured by the dust particles depends on the spatial position, an effect due to the inhomogeneity, and their total lifetime has no non-zero lower limit. Part of the big-crunch singularity is naked. The metric depends on a parameter and contains flat spacetime as a non-singular particular case. For appropriate values of the parameter the spacetime is a small perturbation of Minkowski spacetime. This seems to indicate that flat spacetime may be unstable against some global non-vacuum perturbations.

  14. Shearfree cylindrical gravitational collapse

    SciTech Connect

    Di Prisco, A.; Herrera, L.; MacCallum, M. A. H.; Santos, N. O.

    2009-09-15

    We consider diagonal cylindrically symmetric metrics, with an interior representing a general nonrotating fluid with anisotropic pressures. An exterior vacuum Einstein-Rosen spacetime is matched to this using Darmois matching conditions. We show that the matching conditions can be explicitly solved for the boundary values of metric components and their derivatives, either for the interior or exterior. Specializing to shearfree interiors, a static exterior can only be matched to a static interior, and the evolution in the nonstatic case is found to be given in general by an elliptic function of time. For a collapsing shearfree isotropic fluid, only a Robertson-Walker dust interior is possible, and we show that all such cases were included in Cocke's discussion. For these metrics, Nolan and Nolan have shown that the matching breaks down before collapse is complete, and Tod and Mena have shown that the spacetime is not asymptotically flat in the sense of Berger, Chrusciel, and Moncrief. The issues about energy that then arise are revisited, and it is shown that the exterior is not in an intrinsic gravitational or superenergy radiative state at the boundary.

  15. Shearfree cylindrical gravitational collapse

    NASA Astrophysics Data System (ADS)

    di Prisco, A.; Herrera, L.; MacCallum, M. A. H.; Santos, N. O.

    2009-09-01

    We consider diagonal cylindrically symmetric metrics, with an interior representing a general nonrotating fluid with anisotropic pressures. An exterior vacuum Einstein-Rosen spacetime is matched to this using Darmois matching conditions. We show that the matching conditions can be explicitly solved for the boundary values of metric components and their derivatives, either for the interior or exterior. Specializing to shearfree interiors, a static exterior can only be matched to a static interior, and the evolution in the nonstatic case is found to be given in general by an elliptic function of time. For a collapsing shearfree isotropic fluid, only a Robertson-Walker dust interior is possible, and we show that all such cases were included in Cocke’s discussion. For these metrics, Nolan and Nolan have shown that the matching breaks down before collapse is complete, and Tod and Mena have shown that the spacetime is not asymptotically flat in the sense of Berger, Chrusciel, and Moncrief. The issues about energy that then arise are revisited, and it is shown that the exterior is not in an intrinsic gravitational or superenergy radiative state at the boundary.

  16. Cylindrical rotating triboelectric nanogenerator.

    PubMed

    Bai, Peng; Zhu, Guang; Liu, Ying; Chen, Jun; Jing, Qingshen; Yang, Weiqing; Ma, Jusheng; Zhang, Gong; Wang, Zhong Lin

    2013-07-23

    We demonstrate a cylindrical rotating triboelectric nanogenerator (TENG) based on sliding electrification for harvesting mechanical energy from rotational motion. The rotating TENG is based on a core-shell structure that is made of distinctly different triboelectric materials with alternative strip structures on the surface. The charge transfer is strengthened with the formation of polymer nanoparticles on surfaces. During coaxial rotation, a contact-induced electrification and the relative sliding between the contact surfaces of the core and the shell result in an "in-plane" lateral polarization, which drives the flow of electrons in the external load. A power density of 36.9 W/m(2) (short-circuit current of 90 μA and open-circuit voltage of 410 V) has been achieved by a rotating TENG with 8 strip units at a linear rotational velocity of 1.33 m/s (a rotation rate of 1000 r/min). The output can be further enhanced by integrating more strip units and/or applying larger linear rotational velocity. This rotating TENG can be used as a direct power source to drive small electronics, such as LED bulbs. This study proves the possibility to harvest mechanical energy by TENGs from rotational motion, demonstrating its potential for harvesting the flow energy of air or water for applications such as self-powered environmental sensors and wildlife tracking devices.

  17. On Steady-State Tropical Cyclones

    DTIC Science & Technology

    2014-01-01

    mass-weighted RAM and domain-integrated kinetic energy (KE) partitioned between cyclonic KE (cKE) and anticyclonic KE (aKE) and how does the...and (b) the mass-weighted kinetic energy of cyclonic flow (cKE, where v > 0) and anticyclonic flow (aKE, where v < 0) normalized by the initial value...focus the study, we have sought to quantify for the first time the partition between the kinetic energy of the cyclone itself and the upper-level

  18. Coal reburning application on a Cyclone boiler

    SciTech Connect

    Maringo, G.J.; Yagiela, A.S.; Newell, R.J.; Farzan, H.

    1994-12-31

    Cyclone reburn involves the injection of a supplemental fuel (natural gas, oil or coal) into the main furnace of a Cyclone-fired boiler to produce locally reducing conditions which convert NO{sub x}, generated in the main combustion zone, to molecular nitrogen, thereby reducing overall NO{sub x} emissions. The world`s only application of the Cyclone reburn technology using pulverized coal as the reburn fuel was installed at Wisconsin Power & Light`s Nelson Dewey Generating Station, Unit 2. The project was selected for demonstration under the US Department of Energy`s Clean Coal Technology Demonstration Program, Round II.

  19. Stability of Wavy Films in Gas-Liquid Two-Phase Flows at Normal and Microgravity Conditions

    NASA Technical Reports Server (NTRS)

    Balakotaiah, V.; Jayawardena, S. S.

    1996-01-01

    For flow rates of technological interest, most gas-liquid flows in pipes are in the annular flow regime, in which, the liquid moves along the pipe wall in a thin, wavy film and the gas flows in the core region. The waves appearing on the liquid film have a profound influence on the transfer rates, and hence on the design of these systems. We have recently proposed and analyzed two boundary layer models that describe the characteristics of laminar wavy films at high Reynolds numbers (300-1200). Comparison of model predictions to 1-g experimental data showed good agreement. The goal of our present work is to understand through a combined program of experimental and modeling studies the characteristics of wavy films in annular two-phase gas-liquid flows under normal as well as microgravity conditions in the developed and entry regions.

  20. Three-dimensional direct numerical simulations of co/counter-current vertical gas-Liquid annular flows

    NASA Astrophysics Data System (ADS)

    Farhaoui, Asma; Kahouadji, Lyes; Chergui, Jalel; Juric, Damir; Shin, Seungwon; Craster, Richard; Matar, Omar

    2016-11-01

    We carry out three-dimensional numerical simulations of co/counter current Gas-Liquid annular flows using the parallel code, BLUE, based on a projection method for the resolution of the Navier-Stokes equations and a hybrid Front-Tracking/Level-Set method for the interface advection. Gas-Liquid annular flows and falling films in a pipe are present in a broad range of industrial processes. This configuration consists of an important multiphase flow regime where the liquid occupies the area adjacent to the internal circumference of the pipe and the gas flows in the pipe core. Experimentally, four distinctive flow regimes were identified ('dual-wave', 'thick ripple', 'disturbance wave' and 'regular wave' regimes), that we attempt to simulate. In order to visualize these different regimes, various liquid (water) and gas (air) flow-rates are investigated. EPSRC UK Programme Grant EP/K003976/1.

  1. Pyrolysis-gas-liquid chromatography of fungi: differentiation of species and strains of several members of the Aspergillus flavus group.

    PubMed

    Vincent, P G; Kulik, M M

    1970-12-01

    Four fungi of the Aspergillus flavus group were differentiated to the species level and strain level by pyrolysis-gas-liquid chromotography. Comparisons of pyrochromatograms revealed more similarities than dissimilarities among both species and strains in the pyrolytic elution patterns. Quantitative analysis was made by comparing the number of peaks in which two strains or reference species agreed or disagreed, the degree of superimposability between the pyrolytic elution patterns of strains and reference species, and the presence or absence of peaks for strain pairs within each species. The accuracy and precision of these techniques suggest that pyrolysis-gas-liquid chromatography may have wide application in the detection, enumeration, and identification of fungi by nonmycologically trained personnel.

  2. High efficiency chlorine removal from polyvinyl chloride (PVC) pyrolysis with a gas-liquid fluidized bed reactor.

    PubMed

    Yuan, G; Chen, D; Yin, L; Wang, Z; Zhao, L; Wang, J Y

    2014-06-01

    In this research a gas-liquid fluidized bed reactor was developed for removing chlorine (Cl) from polyvinyl chloride (PVC) to favor its pyrolysis treatment. In order to efficiently remove Cl within a limited time before extensive generation of hydrocarbon products, the gas-liquid fluidized bed reactor was running at 280-320 °C, where hot N2 was used as fluidizing gas to fluidize the molten polymer, letting the molten polymer contact well with N2 to release Cl in form of HCl. Experimental results showed that dechlorination efficiency is mainly temperature dependent and 300 °C is a proper reaction temperature for efficient dechlorination within a limited time duration and for prevention of extensive pyrolysis; under this temperature 99.5% of Cl removal efficiency can be obtained within reaction time around 1 min after melting is completed as the flow rate of N2 gas was set around 0.47-0.85 Nm(3) kg(-1) for the molten PVC. Larger N2 flow rate and additives in PVC would enhance HCl release but did not change the final dechlorination efficiency; and excessive N2 flow rate should be avoided for prevention of polymer entrainment. HCl is emitted from PVC granules or scraps at the mean time they started to melt and the melting stage should be taken into consideration when design the gas-liquid fluidized bed reactor for dechlorination.

  3. US crude oil, natural gas, and natural gas liquids reserves, 1977-1993 (for microcomputers). Data file

    SciTech Connect

    1994-12-31

    The diskette contains all data published in the reserves and production tables of each annual report of U.S. Crude Oil, Natural Gas and Natural Gas Liquids Reserves from 1977 through 1991 listed in 15 separate ASCII files, one per report year. Within each annual file, the records are separated by hydrocarbon type into the following: Crude Oil, Associated Dissolved Natural Gas, Nonassociated Natural Gas, Total Natural Gas, Lease Condensate, Natural Gas Plant Liquids, and Natural Gas Liquids. During the 15 years collated here, the data items gathered and published have changed, with dry versus wet natural gas being the primary difference and the consequent separation of natural gas liquids. The records are also separated by State or State subregions and a few tabulated combinations of States and State subregions. The EIA requirement to hold confidential the data gathered during the annual surveys has driven changes in the States, subregions and combinations published and therefore included in the diskette over the years. Data given on the records are the following: Proved reserves, beginning-of-year; Net Adjustments; Revision increases; Revision decreases; Extensions; New field Discoveries; New reservoirs in old fields; Production; and Reserves, end-of-year.

  4. Numerical and Experimental Investigation of Stratified Gas-Liquid Two-Phase Flow in Horizontal Circular Pipes

    SciTech Connect

    Faccini, J.L.H.; Sampaio, P.A.B. de

    2006-07-01

    This paper reports numerical and experimental investigation of stratified gas-liquid two-phase flow in horizontal circular pipes. The Reynolds averaged Navier Stokes equations (RANS) with the k-{omega} model for a fully developed stratified gas-liquid two-phase flow are solved by using the finite element method. A smooth and horizontal interface surface is assumed without considering the interfacial waves. The continuity of the shear stress across the interface is enforced with the continuity of the velocity being automatically satisfied by the variational formulation. For each given interface position and longitudinal pressure gradient, an inner iteration loop runs to solve the nonlinear equations. The Newton-Raphson scheme is used to solve the transcendental equations by an outer iteration to determine the interface position and pressure gradient for a given pair of volumetric flow rates. The interface position in a 51.2 mm ID circular pipe was measured experimentally by the ultrasonic pulse-echo technique. The numerical results were also compared with experimental results in a 21 mm ID circular pipe reported by Masala [1]. The good agreement between the numerical and experimental results indicates that the k-{omega} model can be applied for the numerical simulation of stratified gas-liquid two-phase flow. (authors)

  5. Large-Eddy Simulation of Transient Horizontal Gas-Liquid Flow in Continuous Casting Using Dynamic Subgrid-Scale Model

    NASA Astrophysics Data System (ADS)

    Liu, Zhongqiu; Li, Baokuan

    2017-03-01

    Euler-Euler simulations of transient horizontal gas-liquid flow in a continuous-casting mold are presented. The predictions were compared with previous experimental measurements by two-channel laser Doppler velocimeter. Simulations were performed to understand the sensitivity to different turbulence closure models [k-ɛ, shear stress transport (SST), Reynolds stress model (RSM), and large-eddy simulation (LES)] and different interfacial forces (drag, lift, virtual mass, wall lubrication, and turbulent dispersion). It was found that the LES model showed better agreement than the other turbulence models in predicting the velocity components of the liquid phase. Furthermore, an appropriate drag force coefficient model, lift force coefficient model, and virtual mass force coefficient were chosen. Meanwhile, the wall lubrication force and turbulent dispersion force did not have much effect on the current gas-liquid two-phase system. This work highlights the importance of choosing an appropriate bubble size in accordance with experiment. Finally, coupled with the optimized interfacial force models and bubble size, LES with a dynamic subgrid model was used to calculate the transient two-phase turbulent flow inside the mold. More instantaneous details of the two-phase flow characteristics in the mold were captured by LES, including multiscale vortex structures, fluctuation characteristics, and the vorticity distribution. The LES model can also be used to describe the time-averaged gas-liquid flow field, giving reasonably good agreement with mean experimental data. Thus, LES can be used effectively to study transient two-phase flow inside molds.

  6. Multi-Scale Morphological Analysis of Conductance Signals in Vertical Upward Gas-Liquid Two-Phase Flow

    NASA Astrophysics Data System (ADS)

    Lian, Enyang; Ren, Yingyu; Han, Yunfeng; Liu, Weixin; Jin, Ningde; Zhao, Junying

    2016-11-01

    The multi-scale analysis is an important method for detecting nonlinear systems. In this study, we carry out experiments and measure the fluctuation signals from a rotating electric field conductance sensor with eight electrodes. We first use a recurrence plot to recognise flow patterns in vertical upward gas-liquid two-phase pipe flow from measured signals. Then we apply a multi-scale morphological analysis based on the first-order difference scatter plot to investigate the signals captured from the vertical upward gas-liquid two-phase flow loop test. We find that the invariant scaling exponent extracted from the multi-scale first-order difference scatter plot with the bisector of the second-fourth quadrant as the reference line is sensitive to the inhomogeneous distribution characteristics of the flow structure, and the variation trend of the exponent is helpful to understand the process of breakup and coalescence of the gas phase. In addition, we explore the dynamic mechanism influencing the inhomogeneous distribution of the gas phase in terms of adaptive optimal kernel time-frequency representation. The research indicates that the system energy is a factor influencing the distribution of the gas phase and the multi-scale morphological analysis based on the first-order difference scatter plot is an effective method for indicating the inhomogeneous distribution of the gas phase in gas-liquid two-phase flow.

  7. The application of a non-thermal plasma generated by gas-liquid gliding arc discharge in sterilization

    NASA Astrophysics Data System (ADS)

    Du, Chang Ming; Wang, Jing; Zhang, Lu; Xia Li, Hong; Liu, Hui; Xiong, Ya

    2012-01-01

    Gliding arc discharge has been investigated in recent years as an innovative physicochemical technique for contaminated water treatment at atmospheric pressure and ambient temperature. In this study we tested a gas-liquid gliding arc discharge reactor, the bacterial suspension of which was treated circularly. When the bacterial suspension was passed through the electrodes and circulated at defined flow rates, almost 100% of the bacteria were killed in less than 3.0 min. Experimental results showed that it is possible to achieve an abatement of 7.0 decimal logarithm units within only 30 s. Circulation flow rates and types of feeding gas caused a certain impact on bacteria inactivation, but the influences are not obvious. So, under the promise of sterilization effect, industrial applications can select their appropriate operating conditions. All inactivation curves presented the same three-phase profile showing an apparent sterilization effect. Analysis of the scanning electron microscope images of bacterial cells supports the speculation that the gas-liquid gliding arc discharge plasma is acting under various mechanisms driven essentially by oxidation and the effect of electric field. These results enhance the possibility of applying gas-liquid gliding arc discharge decontamination systems to disinfect bacterial-contaminated water. Furthermore, correlational research indicates the potential applications of this technology in rapid sterilization of medical devices, spacecraft and food.

  8. Optimization of Cylindrical Hall Thrusters

    SciTech Connect

    Yevgeny Raitses, Artem Smirnov, Erik Granstedt, and Nathaniel J. Fi

    2007-07-24

    The cylindrical Hall thruster features high ionization efficiency, quiet operation, and ion acceleration in a large volume-to-surface ratio channel with performance comparable with the state-of-the-art annular Hall thrusters. These characteristics were demonstrated in low and medium power ranges. Optimization of miniaturized cylindrical thrusters led to performance improvements in the 50-200W input power range, including plume narrowing, increased thruster efficiency, reliable discharge initiation, and stable operation. __________________________________________________

  9. Optimization of Cylindrical Hall Thrusters

    SciTech Connect

    Yevgeny Raitses, Artem Smirnov, Erik Granstedt, and Nathaniel J. Fisch

    2007-11-27

    The cylindrical Hall thruster features high ionization efficiency, quiet operation, and ion acceleration in a large volume-to-surface ratio channel with performance comparable with the state-of-the-art annular Hall thrusters. These characteristics were demonstrated in low and medium power ranges. Optimization of miniaturized cylindrical thrusters led to performance improvements in the 50-200W input power range, including plume narrowing, increased thruster efficiency, reliable discharge initiation, and stable operation.

  10. Electron diffraction from cylindrical nanotubes

    SciTech Connect

    Qin, L.C. )

    1994-09-01

    Electron diffraction intensities from cylindrical objects can be conveniently analyzed using Bessel functions. Analytic formulas and geometry of the diffraction patterns from cylindrical carbon nanotubes are presented in general forms in terms of structural parameters, such as the pitch angle and the radius of a tubule. As an example the Fraunhofer diffraction pattern from a graphitic tubule of structure [18,2] has been simulated to illustrate the characteristics of such diffraction patterns. The validity of the projection approximation is also discussed.

  11. Relaxation limit of a compressible gas-liquid model with well-reservoir interaction

    NASA Astrophysics Data System (ADS)

    Solem, Susanne; Evje, Steinar

    2017-02-01

    This paper deals with the relaxation limit of a two-phase compressible gas-liquid model which contains a pressure-dependent well-reservoir interaction term of the form q (P_r - P) where q>0 is the rate of the pressure-dependent influx/efflux of gas, P is the (unknown) wellbore pressure, and P_r is the (known) surrounding reservoir pressure. The model can be used to study gas-kick flow scenarios relevant for various wellbore operations. One extreme case is when the wellbore pressure P is largely dictated by the surrounding reservoir pressure P_r. Formally, this model is obtained by deriving the limiting system as the relaxation parameter q in the full model tends to infinity. The main purpose of this work is to understand to what extent this case can be represented by a well-defined mathematical model for a fixed global time T>0. Well-posedness of the full model has been obtained in Evje (SIAM J Math Anal 45(2):518-546, 2013). However, as the estimates for the full model are dependent on the relaxation parameter q, new estimates must be obtained for the equilibrium model to ensure existence of solutions. By means of appropriate a priori assumptions and some restrictions on the model parameters, necessary estimates (low order and higher order) are obtained. These estimates that depend on the global time T together with smallness assumptions on the initial data are then used to obtain existence of solutions in suitable Sobolev spaces.

  12. Prediction of acute toxicity of chemicals in mixtures: worms Tubifex tubifex and gas/liquid distribution.

    PubMed

    Tichý, M; Borek-Dohalský, V; Matousová, D; Rucki, M; Feltl, L; Roth, Z

    2002-03-01

    The aim of this contribution is to support our proposal of the procedure for predicting acute toxicity of binary mixtures by QSAR analysis techniques. The changes of a mixture composition are described by molar ratio R and visualized in the R-plot (QCAR--quantitative composition-activity relationships). The approach was inspired by Rault and Dalton's laws, their positive and negative deviations in the behavior of a mixture of real gases, by Loewe and Muischnek isoboles and by the Finney test of additivity. Acute toxicity was determined by the laboratory test with woms Tubifex tubifex. The additivity of the acute toxicity in the binary mixture benzene + nitrobenzene was confirmed and a new interaction is described: "mixed interaction" with the binary mixture aniline + ethanol. The "mixed interaction" means that depending on mixture composition, both potentiation and inhibition can occur. As the first physicochemical descriptor of the changes caused by the changing composition of binary mixtures, the gas/liquid equilibrium was studied and a composition of the gaseous phase was determined by a gas chromatographic method. The method for determination of concentrations in the gaseous phase was described. The gaseous phase composition of benzene + nitrobenzene. benzene + ethanol, benzene + aniline and ethanol + aniline mixtures was analyzed. It was found that if the concentrations of the mixture's components in the gaseous phase behave nonideally (they are not additive), the acute toxicity of the same mixture is not additive as well. Another descriptor to distinguish between potentiation and inhibition will be, however, necessary. The properties, both gaseous phase composition and the acute toxicity, of the benzene + nitrobenzene mixture are additive. In mixtures with the mixed interaction, the R-plot of the composition of the gaseous phase is complex with a large variation of results.

  13. Generating Singlet Oxygen Bubbles: A New Mechanism for Gas-Liquid Oxidations in Water

    PubMed Central

    Bartusik, Dorota; Aebisher, David; Ghafari, BiBi

    2012-01-01

    Laser-coupled microphotoreactors were developed to bubble singlet oxygen [1O2 (1Δg)] into an aqueous solution containing an oxidizable compound. The reactors consisted of custom-modified SMA fiber-optic receptacles loaded with 150-μm silicon phthalocyanine glass sensitizer particles, where the particles were isolated from direct contact with water by a membrane adhesively bonded to the bottom of each device. A tube fed O2 gas to the reactor chambers. In the presence of O2, singlet oxygen was generated by illuminating the sensitizer particles with 669-nm light from an optical fiber coupled to the top of the reactor. The generated 1O2 was transported through the membrane by the O2 stream and formed bubbles in solution. In solution, singlet oxygen reacted with probe compounds (either 9,10-anthracene dipropionate dianion, trans-2-methyl-2-pentanoate anion, N-benzoyl-D,L-methionine, and N-acetyl-D,L-methionine) to give oxidized products in two stages. The early stage was rapid and showed that 1O2 transfer occurred via bubbles mainly in the bulk water solution. The later stage was slow, it arose only from 1O2-probe molecule contact at the gas/liquid interface. A mechanism is proposed that involves 1O2 mass transfer and solvation, where smaller bubbles provide better penetration of 1O2 into the flowing stream due to higher surface-to-volume contact between the probe molecules and 1O2. PMID:22260325

  14. [Rapid simultaneous assay of the principalamide-type local anesthetics by gas-liquid chromatography].

    PubMed

    Desch, G; Cavadore, D; Jullien, Y; Mercier, L; Descomps, B; de Rodez, M

    1981-01-01

    This method can assay simultaneously, using 300 microliters of plasma, of the three principle local anesthetic agents used by peridural injection for post-operative anesthesia and analgesia: xylocaïne, etidocaïne, bupivacaïne. The assay method consists of three steps: (a) the addition of an internal calibrating agent (mepivacaïne). (b) defecation using trichlorocetic acid. (c) alcalinization of the supernatent (pH 11), extraction with dichloromethane and concentration at room temperature of the organic phase. (d) chromotography using an SE 30 or OV 17 impregnated column. The method is sensitive between 0.37 mumoles per l-1 (0.1 microgram . ml-1) and the coefficient for the mean deviation is 10.9% for concentration between 0.37 mumoles 1-1 and 75 mumole1-1 (0.1 microgram . ml-1 and 20 micrograms . ml-1). The correspondence of the figures recorded in this large concentration range without any change in the technique means that the kinetics of the plasma concentrations before and after peridural injection can be followed. The results obtained by gas liquid chromatography for the assay of lidocaïne were compared in 115 different plasma samples with concentrations obtained by an immuno enzymatic method ("EMIT") fitted to a centrifuge analyser. The correlation coefficient between the two methods was: (r = 0.95 with y = 0.09 x +0.25 microgram . ml-1 implying the absence of any interference and the specificity of the two methods. The columns also separate in 20 minutes the two main metabolites of lidocaïne: monoethylglycinexylidide (M.E.G.X.) and glycinexylidide (G.X.). These results demonstrate that continuous peridural injection of lidocaïne produces a high plasma concentration without any clinical toxic phenomena.

  15. Effects of self-pulsation on the spray characteristics of gas-liquid swirl coaxial injector

    NASA Astrophysics Data System (ADS)

    Kang, Zhongtao; Li, Qinglian; Cheng, Peng; Zhang, Xinqiao; Wang, Zhen-guo

    2016-10-01

    To understand the influence of self-pulsation on the spray characteristics of gas-liquid swirl coaxial injector, a back-lighting photography technique has been employed to capture the instantaneous self-pulsated spray and stable spray images with a high speed camera. The diameter and velocity of the droplets in the spray have been characterized with a Dantec Phase Doppler Anemometry (PDA) system. The effects of self-pulsation on the spray pattern, primary breakup, spray angle, diameter and velocity distribution and mass flow rate distribution are analyzed and discussed. The results show that the spray morphology is greatly influenced by self-pulsation. The stable spray has a cone shape, while the self-pulsated spray looks like a Christmas tree. The main difference of these two sprays is the primary breakup. The liquid film of stable spray keeps stable while that of self-pulsated spray oscillates periodically. The film width of self-pulsated spray varies in a large range with 'neck' and 'shoulder' features existing. The liquid film of self-pulsated spray breaks up at the second neck, and then the second shoulder begins to breakup into ligaments. The self-pulsated spray produces droplet clusters periodically, varies horizontal spray width and mass flux periodically. From the point of spatial distribution, self-pulsation is good for the spray, it uniformizes the mass flux along radius and increases the spray angle. However, when self-pulsation occurs, the SMD distribution varies from an inverted V shape to a hollow cone shape, and SMD increases at all the measuring points. Namely, from the point of atomization performance, self-pulsation has negative effects even when the breakup length is smaller. The effects of self-pulsation on the diameter and velocity distributions of the spray are mainly in the center part of the spray. The periphery of stable and self-pulsated spray has similar diameter and velocity distribution.

  16. Tropical Cyclone Jack in Satellite 3-D

    NASA Video Gallery

    This 3-D flyby from NASA's TRMM satellite of Tropical Cyclone Jack on April 21 shows that some of the thunderstorms were shown by TRMM PR were still reaching height of at least 17 km (10.5 miles). ...

  17. Human influence on tropical cyclone intensity

    NASA Astrophysics Data System (ADS)

    Sobel, Adam H.; Camargo, Suzana J.; Hall, Timothy M.; Lee, Chia-Ying; Tippett, Michael K.; Wing, Allison A.

    2016-07-01

    Recent assessments agree that tropical cyclone intensity should increase as the climate warms. Less agreement exists on the detection of recent historical trends in tropical cyclone intensity. We interpret future and recent historical trends by using the theory of potential intensity, which predicts the maximum intensity achievable by a tropical cyclone in a given local environment. Although greenhouse gas-driven warming increases potential intensity, climate model simulations suggest that aerosol cooling has largely canceled that effect over the historical record. Large natural variability complicates analysis of trends, as do poleward shifts in the latitude of maximum intensity. In the absence of strong reductions in greenhouse gas emissions, future greenhouse gas forcing of potential intensity will increasingly dominate over aerosol forcing, leading to substantially larger increases in tropical cyclone intensities.

  18. GPM Flyby of Tropical Cyclone Uriah

    NASA Video Gallery

    On Feb. 15, GPM saw rain was falling at a rate of over 127 mm (5 inches) per hour in a band of intense storms south of Tropical Cyclone Uriah's center. Thunderstorms moving around the southwestern ...

  19. Human Influence on Tropical Cyclone Intensity

    NASA Technical Reports Server (NTRS)

    Sobel, Adam H.; Camargo, Suzana J.; Hall, Timothy M.; Lee, Chia-Ying; Tippett, Michael K.; Wing, Allison A.

    2016-01-01

    Recent assessments agree that tropical cyclone intensity should increase as the climate warms. Less agreement exists on the detection of recent historical trends in tropical cyclone intensity.We interpret future and recent historical trends by using the theory of potential intensity, which predicts the maximum intensity achievable by a tropical cyclone in a given local environment. Although greenhouse gas-driven warming increases potential intensity, climate model simulations suggest that aerosol cooling has largely canceled that effect over the historical record. Large natural variability complicates analysis of trends, as do poleward shifts in the latitude of maximum intensity. In the absence of strong reductions in greenhouse gas emissions, future greenhouse gas forcing of potential intensity will increasingly dominate over aerosol forcing, leading to substantially larger increases in tropical cyclone intensities.

  20. Human influence on tropical cyclone intensity.

    PubMed

    Sobel, Adam H; Camargo, Suzana J; Hall, Timothy M; Lee, Chia-Ying; Tippett, Michael K; Wing, Allison A

    2016-07-15

    Recent assessments agree that tropical cyclone intensity should increase as the climate warms. Less agreement exists on the detection of recent historical trends in tropical cyclone intensity. We interpret future and recent historical trends by using the theory of potential intensity, which predicts the maximum intensity achievable by a tropical cyclone in a given local environment. Although greenhouse gas-driven warming increases potential intensity, climate model simulations suggest that aerosol cooling has largely canceled that effect over the historical record. Large natural variability complicates analysis of trends, as do poleward shifts in the latitude of maximum intensity. In the absence of strong reductions in greenhouse gas emissions, future greenhouse gas forcing of potential intensity will increasingly dominate over aerosol forcing, leading to substantially larger increases in tropical cyclone intensities.

  1. TRMM Flyby of Tropical Cyclone Narelle

    NASA Video Gallery

    This animated, 3-D flyby of Major Cyclone Narelle was created using data on Jan. 11, from NASA's TRMM satellite. Narelle's wind speeds were near 132 mph. A few thunderstorm towers in Narelle's eye ...

  2. Raindrop Size Distribution Measurements in Tropical Cyclones

    NASA Technical Reports Server (NTRS)

    Tokay, Ali; Bashor, Paul G.; Habib, Emad; Kasparis, Takis

    2008-01-01

    Characteristics of the raindrop size distribution in seven tropical cyclones have been studied through impact-type disdrometer measurements at three different sites during the 2004-06 Atlantic hurricane seasons. One of the cyclones has been observed at two different sites. High concentrations of small and/or midsize drops were observed in the presence or absence of large drops. Even in the presence of large drops, the maximum drop diameter rarely exceeded 4 mm. These characteristics of raindrop size distribution were observed in all stages of tropical cyclones, unless the storm was in the extratropical stage where the tropical cyclone and a midlatitude frontal system had merged. The presence of relatively high concentrations of large drops in extratropical cyclones resembled the size distribution in continental thunderstorms. The integral rain parameters of drop concentration, liquid water content, and rain rate at fixed reflectivity were therefore lower in extratropical cyclones than in tropical cyclones. In tropical cyclones, at a disdrometercalculated reflectivity of 40 dBZ, the number concentration was 700 plus or minus 100 drops m(sup -3), while the liquid water content and rain rate were 0.90 plus or minus 0.05 g m(sup -3) and 18.5 plus or minus 0.5 mm h(sup -1), respectively. The mean mass diameter, on the other hand, was 1.67 plus or minus 0.3 mm. The comparison of raindrop size distributions between Atlantic tropical cyclones and storms that occurred in the central tropical Pacific island of Roi-Namur revealed that the number density is slightly shifted toward smaller drops, resulting in higher-integral rain parameters and lower mean mass and maximum drop diameters at the latter site. Considering parameterization of the raindrop size distribution in tropical cyclones, characteristics of the normalized gamma distribution parameters were examined with respect to reflectivity. The mean mass diameter increased rapidly with reflectivity, while the normalized

  3. Tropical cyclone Pam field survey in Vanuatu

    NASA Astrophysics Data System (ADS)

    Fritz, Hermann M.; Pilarczyk, Jessica E.; Kosciuch, Thomas; Hong, Isabel; Rarai, Allan; Harrison, Morris J.; Jockley, Fred R.; Horton, Benjamin P.

    2016-04-01

    Severe tropical cyclone Pam (Cat. 5, SSHS) crossed the Vanuatu archipelago with sustained winds of 270 km/h on March 13 and 14, 2015 and made landfall on Erromango. Pam is the most intense tropical cyclone to make landfall on Vanuatu since the advent of satellite imagery based intensity estimates in the 1970s. Pam caused one of the worst natural disaster in Vanuatu's recorded history. Eleven fatalities were directly attributed to cyclone Pam and mostly due to lack of shelter from airborne debris. On March 6 Pam formed east of the Santa Cruz Islands causing coastal inundation on Tuvalu's Vaitupu Island located some 1100 km east of the cyclone center. Pam intensified while tracking southward along Vanuatu severely affecting the Shefa and Tafea Provinces. An international storm surge reconnaissance team was deployed to Vanuatu from June 3 to 17, 2015 to complement earlier local surveys. Cyclone Pam struck a remote island archipelago particularly vulnerable to the combined cyclonic multi-hazards encompassing extreme wind gusts, massive rainfall and coastal flooding due to a combination of storm surge and storm wave impacts. The team surveyed coastal villages on Epi, the Shepherd Islands (Tongoa and Mataso), Efate (including Lelepa), Erromango, and Tanna. The survey spanned 320 km parallel to the cyclone track between Epi and Tanna encompassing more than 45 sites including the hardest hit settlements. Coastal flooding profiles were surveyed from the shoreline to the limit of inundation. Maximum coastal flood elevations and overland flow depths were measured based on water marks on buildings, scars on trees, rafted debris and corroborated with eyewitness accounts. We surveyed 91 high water marks with characteristic coastal flood levels in the 3 to 7 m range and composed of storm surge with superimposed storm waves. Inundation distances were mostly limited to a few hundred meters but reached 800 m on Epi Island. Wrack lines containing pumice perfectly delineated the

  4. Interactions between climate and tropical cyclones

    NASA Astrophysics Data System (ADS)

    Webster, P. J.

    2007-05-01

    For the last 50 years, there have been two major thrusts in tropical cyclone research: determining the state of the atmosphere and ocean that is suitable for the formation of tropical storms (the genesis criteria) and short-term forecasting of the track and intensity of storms. Efforts to forecast seasonal storm activity, especially in the North Atlantic Ocean, have been undertaken through empirical means and, more recently, using low-resolution climate models. Climate model results have been exceptionally encouraging suggesting that the tropical cyclogenesis factors are predictable and are part of the large scale tropical circulation. During the last few years, a spate of papers has noted the relationship between changes in sea-surface temperature (SST) and tropical cyclone intensity and frequency. A critical issue is determining to what degree the frequency of hurricanes, as well as their intensity distribution, will change in a warming world. We discuss recent research regarding the interactions of the climate system with tropical cyclones, including the role of climate in determining the genesis of tropical cyclones and the role of tropical cyclones in the heat balance of the planet. Specifically: (i) We re-examine the genesis criteria of tropical cyclones and add two new criteria based on the behavior of waves in a flow varying in longitude and the inertial instability of equatorial flow in a cross-equatorial pressure gradient environment. Tropical cyclones are seen to form where the stretching deformation is negative and where large-scale waves transform into tight smaller and highly energetic scale vortices. We also discuss the tendency for storms to develop and intensify where the near-equatorial flow is inertially unstable. (ii) Tropical cyclones act to cool the tropical oceans by > 1K/year by evaporation of ocean surface water and by entrainment mixing with cooler water from below the mixed layer. We suggest that tropical cyclones are important part of

  5. Idealized simulations of sting jet cyclones

    NASA Astrophysics Data System (ADS)

    Baker, L. H.; Gray, S. L.; Clark, P. A.

    2012-04-01

    An idealized modeling study of sting-jet cyclones is presented. Sting jets are descending mesoscale jets that occur in some extratropical cyclones and produce localized regions of strong low-level winds in the frontal fracture region. Moist baroclinic lifecycle (LC1) simulations are performed with modifications to produce cyclones resembling observed sting-jet cyclones. Two jets exist in the control idealized cyclone that descend into the frontal fracture region and result in strong winds near to the top of the boundary layer; one of these satisfies the criteria for a sting jet, the other is associated with the warm front. Sensitivity experiments show that both these jets are robust features. The sting jet strength (measured by maximum low-level wind speed or descent rate) increases with the cyclone growth rate; growth rate increases with increasing basic-state zonal jet maximum or decreasing basic-state tropospheric static stability. The two cyclones with the weakest basic-state static stability have by far the strongest sting jets, with descent rates comparable to those observed. Evaporative cooling contributes up to 20% of the descent rate in these sting jets compared with up to 4% in the other sting jets. Conditional symmetric instability (CSI) release in the cloud head also contributes to the sting jet, although there is less extensive CSI than in observed cases. The robustness of the sting jets suggests that they could occur frequently in cyclones with frontal fracture; however, they are unlikely to be identified unless momentum transport through the boundary layer leads to strong surface wind gusts.

  6. Generalized offset surfaces of cylindrical surfaces

    NASA Astrophysics Data System (ADS)

    Georgiev, Georgi Hristov

    2016-12-01

    Cylindrical surfaces play an important role in geometric modeling and architecture. In this paper, we describe a way for constructing a new cylindrical surface from a given cylindrical surface. Our approach is based on the differential geometry of cylindrical surfaces and a generalization of the notion of offset surface. We examine the case of a similarity offset of an arbitrary cylindrical surface which is closely related to direct similarities of Euclidean 3-space. Some illustrative examples are included.

  7. The Morphology of Cyclonic Windstorms

    NASA Astrophysics Data System (ADS)

    Hewson, Tim

    2015-04-01

    The aim of this study is to help facilitate the correct interpretation and use of model analyses and predictions of windstorms in the extra-tropics, and to show that 'storm detection' does not just depend on the efficacy of the identification/tracking algorithm. Under the auspices of the IMILAST (Intercomparison of MId-LAtitude STorm diagnostics) project, 29 damaging European cyclonic windstorms have been studied in detail, using observational evidence as the main tool. Accordingly a conceptual model of windstorm evolution has been constructed. This usefully has its roots in the evolution one sees on standard synoptic charts, and highlights that three types of damage footprint can be associated. Building on previous work these are referred to as the warm jet, the sting jet and the cold jet footprints. The jet phenomena themselves each relate to the proximity of fronts on the synoptic charts, and accordingly occur in airmasses with different stability characteristics. These characteristics seem to play a large role in determining the magnitude of surface gusts, and how those gusts vary between coastal and inland sites. These aspects will be discussed with examples, showing that one cannot simply characterise or rank cyclones using wind strength on a lower tropospheric level such as 850hPa. A key finding that sets the sting jet apart, and that makes it a particularly dangerous phenomena, is that gust magnitude is relatively unaffected by passage inland, and this seems to relate to the atmosphere in its environment being destabilised from above. For sting jets wind strength may be greatest below 850hPa. Unfortunately neither current generation global re-analyses, nor global climate models seem to be able to simulate sting jets. This is for various reasons, though their low resolution is key. This limitation has been recognised previously, and the standard way to address this has been to use a re-calibration technique. The potential pitfalls of this approach will be

  8. Linear and nonlinear instability in vertical counter-current laminar gas-liquid flows

    NASA Astrophysics Data System (ADS)

    Schmidt, Patrick; Ó Náraigh, Lennon; Lucquiaud, Mathieu; Valluri, Prashant

    2016-04-01

    We consider the genesis and dynamics of interfacial instability in vertical gas-liquid flows, using as a model the two-dimensional channel flow of a thin falling film sheared by counter-current gas. The methodology is linear stability theory (Orr-Sommerfeld analysis) together with direct numerical simulation of the two-phase flow in the case of nonlinear disturbances. We investigate the influence of two main flow parameters on the interfacial dynamics, namely the film thickness and pressure drop applied to drive the gas stream. To make contact with existing studies in the literature, the effect of various density contrasts is also examined. Energy budget analyses based on the Orr-Sommerfeld theory reveal various coexisting unstable modes (interfacial, shear, internal) in the case of high density contrasts, which results in mode coalescence and mode competition, but only one dynamically relevant unstable interfacial mode for low density contrast. A study of absolute and convective instability for low density contrast shows that the system is absolutely unstable for all but two narrow regions of the investigated parameter space. Direct numerical simulations of the same system (low density contrast) show that linear theory holds up remarkably well upon the onset of large-amplitude waves as well as the existence of weakly nonlinear waves. For high density contrasts, corresponding more closely to an air-water-type system, linear stability theory is also successful at determining the most-dominant features in the interfacial wave dynamics at early-to-intermediate times. Nevertheless, the short waves selected by the linear theory undergo secondary instability and the wave train is no longer regular but rather exhibits chaotic motion. The same linear stability theory predicts when the direction of travel of the waves changes — from downwards to upwards. We outline the practical implications of this change in terms of loading and flooding. The change in direction of the

  9. Acoustic probe for the characterization of solid-gas- liquid slurries

    NASA Astrophysics Data System (ADS)

    Norato, Michael Anthony

    1999-10-01

    The development of nuclear weapons technology during the Cold War Era has left a legacy of large quantities of radioactive waste which are stored throughout the US Department of Energy (US DOE) Nuclear Weapons Complex. During the proposed remediation stages of processing, it will be necessary to characterize and monitor these waste slurries by remote methods. Acoustic probes have shown promise because of their non- intrusive nature and ability to penetrate optically opaque slurries. A forward theory for the acoustic response in both dilute and concentrated solid liquid slurries is developed. It is based on ensemble averaging of the equations of motion in the solid and liquid phases to obtain expressions for the ``effective properties'' of the slurry mixture in terms of coefficients which appear in the equations of motion for the solid particle. The attenuations predicted from the theory are in generally good agreement with the experimental data obtained by Toneburst and Pulse/FFT data acquisition methods for solid-liquid slurries of soda-lime glass particles of 14.9 μm and 65 μm mean radius and polystyrene particles of 79 gm radius at concentrations ranging from 5% to 50% solids by volume. The forward theory is readily extended to systems containing more than one dispersed phase, such as particles and gas bubbles, and the theory predictions are observed to be in good agreement with preliminary attenuation data obtained in solid-gas-liquid slurries of soda-lime glass particles of 14.9 gm mean radius at 5% and 10% by volume and gas bubbles ranging from approximately 25 μm to 150 μm radius at volume fractions on the order of 10-5. An inverse theory is also developed to determine the concentration and solids volume fraction distribution in a solid-liquid slurry given its experimentally obtained acoustic response. A Tikhonov scheme is employed to regularize the ill-posed integro-differential equations and solve them as a linear programming problem. Solution of the

  10. Tracking Southern Hemisphere extratropical cyclones using different algorithms

    NASA Astrophysics Data System (ADS)

    Tilinina, Natalia; Rudeva, Irina; Gulev, Sergey; Simmonds, Ian; Keay, Kevin

    2010-05-01

    We attempt to estimate strengths and weaknesses of the two cyclone tracking algorithms - of the University of Melbourne (UM) and of IORAS (SAIL). The UM scheme is using geostrophic vorticity for tracking cyclones and SAIL tracking is based on sea level pressure. Furthermore, there are many other conceptual differences in the algorithm performance. The SAIL scheme was applied to the NCEP-NCAR reanalysis output for the Southern Hemisphere (1948-2009), the period of intercomparison with the results based on UM scheme was 1990-1999. During time period 1990-1999 the UM scheme identifies 45% more cyclones than the SAIL scheme. The UM tracking output consists of all cyclones which are found by the SAIL scheme and also many short-living vortices, which do not have their imprints in the pressure fields. Many of these vortices are not characterized by the minimum central pressure and the closed isobar - the two major characteristics of cyclone - and require the extension of cyclone definition to be considered as cyclones. Spatial distribution of cyclone counts over Southern Hemisphere clearly shows the two main storm tracks: the Southern (close to the Antarctic) represented by deep and moderate cyclones with minimum central pressure typically lower than 965 hPa and the Northern track primarily associated with the shallow cyclones (central pressure is typically higher than 980hPa). Using the time series of the number of cyclones derived from the SAIL tracking we estimated linear trends in the cyclones counts. The number of deep cyclones (<960 hPa) growths during 1948-2009 by 0,8 cyclones per year, while the number of shallow cyclones (>980 hPa) decreases by 1,3 cyclones per year. Changes in a number of deep cyclones are significantly correlated with the Southern Oscillation Index (e.g. 0,57 in the autumn).

  11. Cylindrical acoustic levitator/concentrator

    DOEpatents

    Kaduchak, Gregory; Sinha, Dipen N.

    2002-01-01

    A low-power, inexpensive acoustic apparatus for levitation and/or concentration of aerosols and small liquid/solid samples having particulates up to several millimeters in diameter in air or other fluids is described. It is constructed from a commercially available, hollow cylindrical piezoelectric crystal which has been modified to tune the resonance frequency of the breathing mode resonance of the crystal to that of the interior cavity of the cylinder. When the resonance frequency of the interior cylindrical cavity is matched to the breathing mode resonance of the cylindrical piezoelectric transducer, the acoustic efficiency for establishing a standing wave pattern in the cavity is high. The cylinder does not require accurate alignment of a resonant cavity. Water droplets having diameters greater than 1 mm have been levitated against the force of gravity using; less than 1 W of input electrical power. Concentration of aerosol particles in air is also demonstrated.

  12. Cyclone reduction of taconite. Final report

    SciTech Connect

    Taylor, P.R.; Bartlett, R.W.; Abdel-latif, M.A.; Hou, X.; Kumar, P.

    1995-05-01

    A cyclone reactor system for the partial reduction and melting of taconite concentrate fines has been engineered, designed and operated. A non-transferred arc plasma torch was employed as a heat source. Taconite fines, carbon monoxide, and carbon dioxide were fed axially into the reactor, while the plasma gas was introduced tangentially into the cyclone. The average reactor temperature was maintained at above 1400{degrees}C, and reduction experiments were performed under various conditions. The influence of the following parameters on the reduction of taconite was investigated experimentally; carbon monoxide to carbon dioxide inlet feed ratio, carbon monoxide inlet partial pressure, and average reactor temperature. The interactions of the graphite lining with carbon dioxide and taconite were also studied. An attempt was made to characterize the flow behavior of the molten product within the cyclone. The results suggest that the system may approach a plug flow reactor, with little back mixing. Finally, a fundamental mathematical model was developed. The model describes the flow dynamics of gases and solid particles in a cyclone reactor, energy exchange, mass transfer, and the chemical kinetics associated with cyclone smelting of taconite concentrate fines. The influence of the various parameters on the reduction and melting of taconite particles was evaluated theoretically.

  13. Raindrop Size Distribution Measurements in Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Tokay, A.; Bashor, P. G.; Habib, E.; Kasparis, T. C.

    2006-12-01

    Measurements of the raindrop size distribution (RSD) have been collected in tropical cyclones and hurricanes with an impact type disdrometer during the past three Atlantic hurricane seasons. The measurements were taken at Wallops Island, Virginia, Lafayette, Louisiana, and Orlando, Florida. The RSDs from the remnants of tropical cyclones or hurricanes at 40 dBZ agreed well with each other where the mean mass diameter was 1.65-1.7 mm, and the total concentration had a range of 600 to 800 drops/m3. Assuming the normalized gamma size distribution, the shape parameter will be 5-8 to satisfy the observed rain rate of 18-20 mm/hr. If the observations were taken during the extratropical phase of the storm where the tropical cyclone merges with a frontal system, the composite spectra at 40 dBZ include more large drops and less small to mid-size drops, typical for continental thunderstorms. Thus, the mean mass diameter was larger, while total concentration, and rain rate was less in extratropical cyclones than in tropical cyclones.

  14. Citizen scientists analyzing tropical cyclone intensities

    NASA Astrophysics Data System (ADS)

    Hennon, Christopher C.

    2012-10-01

    A new crowd sourcing project called CycloneCenter enables the public to analyze historical global tropical cyclone (TC) intensities. The primary goal of CycloneCenter, which launched in mid-September, is to resolve discrepancies in the recent global TC record arising principally from inconsistent development of tropical cyclone intensity data. The historical TC record is composed of data sets called "best tracks," which contain a forecast agency's best assessment of TC tracks and intensities. Best track data have improved in quality since the beginning of the geostationary satellite era in the 1960s (because TCs could no longer disappear from sight). However, a global compilation of best track data (International Best Track Archive for Climate Stewardship (IBTrACS)) has brought to light large interagency differences between some TC best track intensities, even in the recent past [Knapp et al., 2010Knapp et al., 2010]. For example, maximum wind speed estimates for Tropical Cyclone Gay (1989) differed by as much as 70 knots as it was tracked by three different agencies.

  15. Cyclone disaster vulnerability and response experiences in coastal Bangladesh.

    PubMed

    Alam, Edris; Collins, Andrew E

    2010-10-01

    For generations, cyclones and tidal surges have frequently devastated lives and property in coastal and island Bangladesh. This study explores vulnerability to cyclone hazards using first-hand coping recollections from prior to, during and after these events. Qualitative field data suggest that, beyond extreme cyclone forces, localised vulnerability is defined in terms of response processes, infrastructure, socially uneven exposure, settlement development patterns, and livelihoods. Prior to cyclones, religious activities increase and people try to save food and valuable possessions. Those in dispersed settlements who fail to reach cyclone shelters take refuge in thatched-roof houses and big-branch trees. However, women and children are affected more despite the modification of traditional hierarchies during cyclone periods. Instinctive survival strategies and intra-community cooperation improve coping post cyclone. This study recommends that disaster reduction programmes encourage cyclone mitigation while being aware of localised realities, endogenous risk analyses, and coping and adaptation of affected communities (as active survivors rather than helpless victims).

  16. Dust cyclone technology for gins – A literature review

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dust cyclone research leading to more efficient designs has helped the cotton ginning industry to comply with increasingly stringent air quality regulations governing fine particulate emissions. Future changes in regulations may require additional improvements in dust cyclone efficacy. This inter-...

  17. Telescoping cylindrical piezoelectric fiber composite actuator assemblies

    NASA Technical Reports Server (NTRS)

    Allison, Sidney G. (Inventor); Shams, Qamar A. (Inventor); Fox, Robert L. (Inventor); Fox, legal representative, Christopher L. (Inventor); Fox Chattin, legal representative, Melanie L. (Inventor)

    2010-01-01

    A telescoping actuator assembly includes a plurality of cylindrical actuators in a concentric arrangement. Each cylindrical actuator is at least one piezoelectric fiber composite actuator having a plurality of piezoelectric fibers extending parallel to one another and to the concentric arrangement's longitudinal axis. Each cylindrical actuator is coupled to concentrically-adjacent ones of the cylindrical actuators such that the plurality of cylindrical actuators can experience telescopic movement. An electrical energy source coupled to the cylindrical actuators applies actuation energy thereto to generate the telescopic movement.

  18. Augmentation of Early Intensity Forecasting in Tropical Cyclones

    DTIC Science & Technology

    2012-09-30

    1 Augmentation of Early Intensity Forecasting in Tropical Cyclones J. Scott Tyo College of Optical Sciences University of Arizona Tucson, AZ...automatic intensity estimator of Tropical Cyclones (TCs) based on satellite infrared (IR) imagery. The proposed methodology analyzes the TC’s structure to...procedure to objectively estimate the intensity of tropical cyclones . The level of axisymmetry of tropical cyclones is quantified by calcualting the

  19. The tropical cyclone diurnal cycle

    NASA Astrophysics Data System (ADS)

    Dunion, Jason P.

    The research presented in this thesis explores a phenomenon referred to as the tropical cyclone (TC) diurnal cycle (TCDC) and presents satellite, numerical modeling, and observational perspectives pertaining to how it can be monitored, its evolution in time and space, its relevance to TC structure and intensity, and how it manifests in numerical simulations of TCs. Infrared satellite imagery was developed and used to investigate diurnal oscillations in TCs and finds a diurnal pulsing pattern that occurs with notable regularity through a relatively deep layer from the inner core to the surrounding environment. A combination of satellite, numerical model simulations, and aircraft observations found diurnal signals in operationally analyzed radii of 50 kt winds in TCs and in satellite intensity estimates from the Advanced Dvorak Technique and spawned the development of a 24-hr conceptual clock that approximates the temporal and spatial evolution of the TCDC each day. TC diurnal pulses are revealed to significantly impact the thermodynamics and winds in the TC environment and appear as narrow, convectively active rings of high radar reflectivity in NOAA aircraft radar data and are hundreds of kilometers in length. Enhanced nighttime radiational cooling that is particularly favored in the TC outflow layer acts to pre-condition the TC environment in a way that favors triggering of the TCDC and TC diurnal pulses, while in the daytime, the stabilizing effects of shortwave warming begins to suppress TCDC processes in the storm, leading to the culmination of the TCDC each day. Schematics are presented that summarize many of the main findings in this work, including descriptions of the basic state of the TC environment as the TCDC evolves during its early and later stages each day and a TCDC-centric daytime evolution of a TC diurnal pulse, associated squall lines and gust fronts, and radial and vertical winds in the lower and upper levels of the storm. The TCDC represents a

  20. Cyclone contribution to the Mediterranean Sea water budget

    NASA Astrophysics Data System (ADS)

    Flaounas, E.; Di Luca, A.; Drobinski, P.; Mailler, S.; Arsouze, T.; Bastin, S.; Beranger, K.; Lebeaupin Brossier, C.

    2016-02-01

    This paper analyzes the impact of cyclones to the atmospheric components on the Mediterranean Sea Water Budget, namely the cyclones contribution to precipitation and evaporation over the Mediterranean Sea. Three regional simulations were performed with the WRF model for the period 1989-2008. The model was run (1) as a standalone model, (2) coupled with the oceanic model NEMO-MED12 and (3) forced by the smoothed Sea Surface Temperature (SST) fields from the second simulation. Cyclones were tracked in all simulations, and their contribution to the total rainfall and evaporation was quantified. Results show that cyclones are mainly associated with extreme precipitation, representing more than 50 % of the annual rainfall over the Mediterranean Sea. On the other hand, we found that cyclone-induced evaporation represents only a small fraction of the annual total, except in winter, when the most intense Mediterranean cyclones take place. Despite the significant contribution of cyclones to rainfall, our results show that there is a balance between cyclone-induced rainfall and evaporation, suggesting a weak net impact of cyclones on the Mediterranean Sea water budget. The sensitivity of our results with respect to rapid SST changes during the development of cyclones was also investigated. Both rainfall and evaporation are affected in correlation with the SST response to the atmosphere. In fact, air feedbacks to the Mediterranean Sea during the cyclones occurrence were shown to cool down the SST and consequently to reduce rainfall and evaporation at the proximity of cyclone centers.

  1. Ensemble Data Assimilation and Predictability of Tropical Cyclones

    DTIC Science & Technology

    2012-09-30

    on comparing and coupling the ensemble and variational data assimilation methods for tropical cyclone applications. Mr. Melhauser, who started to work...understanding of tropical cyclone predictability and further developed ensemble-based data assimilation methods for tropical cyclones. Now that we have

  2. Ensemble Data Assimilation and Predictability of Tropical Cyclones

    DTIC Science & Technology

    2013-09-30

    comparing and coupling the ensemble and variational data assimilation methods for tropical cyclone applications using past field campaign observations...understanding of tropical cyclone predictability and further developed ensemble-based data assimilation methods for tropical cyclones. Now that we have

  3. Augmentation of Early Intensity Forecasting in Tropical Cyclones

    DTIC Science & Technology

    2012-09-30

    Rodriguez- Herrera, Matthew E. Kucas, and James W. E. Darlow, “A Web-based Interactive Interface for Researching and Forecasting Tropical Cyclone ...Augmentation of Early Intensity Forecasting in Tropical Cyclones J. Scott Tyo College of Optical Sciences...an objective and automatic intensity estimator of Tropical Cyclones (TCs) based on satellite infrared (IR) imagery. The proposed methodology analyzes

  4. Model finds bigger, stronger tropical cyclones with warming seas

    NASA Astrophysics Data System (ADS)

    Schultz, Colin

    2014-03-01

    In the wake of powerful tropical cyclones such as Hurricanes Sandy and Katrina and Typhoon Haiyan, questions about the likely effect of climate change on tropical cyclone activity are on the public's mind. The interactions between global warming and cyclone activity, however, are complex, with rising sea surface temperatures, changing energy distributions, and altered atmospheric dynamics all having some effect.

  5. Optics Demonstrations Using Cylindrical Lenses

    ERIC Educational Resources Information Center

    Ivanov, Dragia; Nikolov, Stefan

    2015-01-01

    In this paper we consider the main properties of cylindrical lenses and propose several demonstrational experiments that can be performed with them. Specifically we use simple glasses full of water to demonstrate some basic geometrical optics principles and phenomena. We also present some less standard experiments that can be performed with such…

  6. Blast waves from cylindrical charges

    NASA Astrophysics Data System (ADS)

    Knock, C.; Davies, N.

    2013-07-01

    Comparisons of explosives are often carried out using TNT equivalency which is based on data for spherical charges, despite the fact that many explosive charges are not spherical in shape, but cylindrical. Previous work has shown that it is possible to predict the over pressure and impulse from the curved surface of cylindrical charges using simple empirical formulae for the case when the length-to-diameter ( L/ D) ratio is greater or equal to 2/1. In this paper, by examining data for all length-to-diameter ratios, it is shown that it is possible to predict the peak over pressure, P, for any length-to-diameter ratio from the curved side of a bare cylindrical charge of explosive using the equation P=K_PM(L/D)^{1/3}/R^3, where M is the mass of explosive, R the distance from the charge and K_P is an explosive-dependent constant. Further out where the cylindrical blast wave `heals' into a spherical one, the more complex equation P=C_1(Z^' ' })^{-3}+C_2(Z^' ' })^{-2}+C_3(Z^' ' })^{-1} gives a better fit to experimental data, where Z^' ' } = M^{1/3}(L/D)^{1/9}/D and C_1, C_2 and C_3 are explosive-dependent constants. The impulse is found to be independent of the L/ D ratio.

  7. Design of Stairmand-type sampling cyclones

    SciTech Connect

    Moore, M.E.; McFarland, A.R. )

    1990-03-01

    An empirical, nondimensional correlation of cut-point Stokes number (Stk0.5) and flow Reynolds number (Re) has been established for small Stairmand-type sampling cyclones. Four cyclones with body diameters of 38, 57, 89, and 140 mm were constructed and tested with monodisperse aerosols over a range of flow rates. The flow rates were chosen to provide preselected increments of particle Froude numbers. These flow rates for the four cyclones spanned the range of 9.4 to 1080 L/min and provided Froude numbers of 1.5, 2.0, 2.5, and 6.0. The resulting Reynolds numbers (based upon cyclone body diameter and inlet flow rate) covered the range of 2.1 x 10(3) to 6.4 x 10(4). Sizes of monodisperse aerosols used in this study were from 3.0- to 17.4-microns aerodynamic diameter. The graphical correlation between cut-point Stokes number and Reynolds number showed there to be no effect of Froude number (for the range of Froude numbers tested). The data have been fit by a least squares procedure to a quadratic logarithmic function. In addition to development of the empirical correlation, the results of this study also provide data pertinent to the regional deposition of liquid particles within the cyclone and to the transmission of solid particles through the cyclone. The carryover of solid, 19-microns diameter particles is only 0.5% greater than that of liquid particles of the same size.

  8. Simulating Gas-Liquid-Water Partitioning and Fluid Properties of Petroleum under Pressure: Implications for Deep-Sea Blowouts.

    PubMed

    Gros, Jonas; Reddy, Christopher M; Nelson, Robert K; Socolofsky, Scott A; Arey, J Samuel

    2016-07-19

    With the expansion of offshore petroleum extraction, validated models are needed to simulate the behaviors of petroleum compounds released in deep (>100 m) waters. We present a thermodynamic model of the densities, viscosities, and gas-liquid-water partitioning of petroleum mixtures with varying pressure, temperature, and composition based on the Peng-Robinson equation-of-state and the modified Henry's law (Krychevsky-Kasarnovsky equation). The model is applied to Macondo reservoir fluid released during the Deepwater Horizon disaster, represented with 279-280 pseudocomponents, including 131-132 individual compounds. We define >n-C8 pseudocomponents based on comprehensive two-dimensional gas chromatography (GC × GC) measurements, which enable the modeling of aqueous partitioning for n-C8 to n-C26 fractions not quantified individually. Thermodynamic model predictions are tested against available laboratory data on petroleum liquid densities, gas/liquid volume fractions, and liquid viscosities. We find that the emitted petroleum mixture was ∼29-44% gas and ∼56-71% liquid, after cooling to local conditions near the broken Macondo riser stub (∼153 atm and 4.3 °C). High pressure conditions dramatically favor the aqueous dissolution of C1-C4 hydrocarbons and also influence the buoyancies of bubbles and droplets. Additionally, the simulated densities of emitted petroleum fluids affect previous estimates of the volumetric flow rate of dead oil from the emission source.

  9. Integrated CO2 capture-fixation chemistry via interfacial ionic liquid catalyst in laminar gas/liquid flow.

    PubMed

    Vishwakarma, Niraj K; Singh, Ajay K; Hwang, Yoon-Ho; Ko, Dong-Hyeon; Kim, Jin-Oh; Babu, A Giridhar; Kim, Dong-Pyo

    2017-03-06

    Simultaneous capture of carbon dioxide (CO2) and its utilization with subsequent work-up would significantly enhance the competitiveness of CO2-based sustainable chemistry over petroleum-based chemistry. Here we report an interfacial catalytic reaction platform for an integrated autonomous process of simultaneously capturing/fixing CO2 in gas-liquid laminar flow with subsequently providing a work-up step. The continuous-flow microreactor has built-in silicon nanowires (SiNWs) with immobilized ionic liquid catalysts on tips of cone-shaped nanowire bundles. Because of the superamphiphobic SiNWs, a stable gas-liquid interface maintains between liquid flow of organoamines in upper part and gas flow of CO2 in bottom part of channel. The intimate and direct contact of the binary reagents leads to enhanced mass transfer and facilitating reactions. The autonomous integrated platform produces and isolates 2-oxazolidinones and quinazolines-2,4(1H,3H)-diones with 81-97% yields under mild conditions. The platform would enable direct CO2 utilization to produce high-valued specialty chemicals from flue gases without pre-separation and work-up steps.

  10. Comprehensive study of the evolution of gas-liquid partitioning of aroma compounds during wine alcoholic fermentation.

    PubMed

    Morakul, Sumallika; Athes, Violaine; Mouret, Jean-Roch; Sablayrolles, Jean-Marie

    2010-09-22

    Calculating the gas-liquid partitioning of aromatic molecules during winemaking fermentation is essential to minimize the loss of aroma and to optimize the fermentation conditions. In this study, the effect of the main fermentation parameters on the partition coefficients (ki) of higher alcohols (2-methylpropan-1-ol and 3-methyl butan-1-ol) and esters (ethyl acetate, 3-methyl-1-butyl acetate, and 2-ethyl hexanoate) was assessed. The values of ki were first determined in synthetic media simulating must and wine. They varied considerably with both the hydrophobicity of the compound and the composition of the medium. Then, the effect of temperature on ki was quantified. The absence of any effect of gas composition was also established by replacing air with CO2. Finally, the impact of CO2 stripping was assessed by running specific fermentations in which the rate of CO2 production was kept constant by perfusion with assimilable nitrogen. These fermentations showed that in contrast to temperature and must composition, CO2 stripping did not change the gas-liquid partitioning of higher alcohols and esters.

  11. A New Void Fraction Measurement Method for Gas-Liquid Two-Phase Flow in Small Channels.

    PubMed

    Li, Huajun; Ji, Haifeng; Huang, Zhiyao; Wang, Baoliang; Li, Haiqing; Wu, Guohua

    2016-01-27

    Based on a laser diode, a 12 × 6 photodiode array sensor, and machine learning techniques, a new void fraction measurement method for gas-liquid two-phase flow in small channels is proposed. To overcome the influence of flow pattern on the void fraction measurement, the flow pattern of the two-phase flow is firstly identified by Fisher Discriminant Analysis (FDA). Then, according to the identification result, a relevant void fraction measurement model which is developed by Support Vector Machine (SVM) is selected to implement the void fraction measurement. A void fraction measurement system for the two-phase flow is developed and experiments are carried out in four different small channels. Four typical flow patterns (including bubble flow, slug flow, stratified flow and annular flow) are investigated. The experimental results show that the development of the measurement system is successful. The proposed void fraction measurement method is effective and the void fraction measurement accuracy is satisfactory. Compared with the conventional laser measurement systems using standard laser sources, the developed measurement system has the advantages of low cost and simple structure. Compared with the conventional void fraction measurement methods, the proposed method overcomes the influence of flow pattern on the void fraction measurement. This work also provides a good example of using low-cost laser diode as a competent replacement of the expensive standard laser source and hence implementing the parameter measurement of gas-liquid two-phase flow. The research results can be a useful reference for other researchers' works.

  12. Spray formation in a quasiplanar gas-liquid mixing layer at moderate density ratios: A numerical closeup

    NASA Astrophysics Data System (ADS)

    Ling, Yue; Fuster, Daniel; Zaleski, Stéphane; Tryggvason, Grétar

    2017-01-01

    The three-dimensional development of instabilities and the subsequent spray formation in a gas-liquid mixing layer are important fundamental problems in the area of multiphase flows. It is highly desirable to visualize this detailed atomization process and to analyze the instabilities and mechanisms involved, and massive numerical simulations are required, in addition to experiment. Rapid development of numerical methods and computer technology in the past decade now allows large-scale three-dimensional direct numerical simulations of atomization to be performed. Nevertheless, the fundamental question, whether all the physical scales involved in the primary breakup process are faithfully resolved, has eluded researchers until now. In the present study, we conduct direct numerical simulations of spray formation in a gas-liquid mixing layer with state-of-the-art computational resources (using up to 4 ×109 cells and 16 384 cores), in order to obtain a high-fidelity numerical closeup of the detailed mechanisms of spray formation. We also aim to examine whether present computational resources are sufficient for a fully resolved direct numerical simulation of atomization.

  13. Characterizing the correlations between local phase fractions of gas-liquid two-phase flow with wire-mesh sensor.

    PubMed

    Tan, C; Liu, W L; Dong, F

    2016-06-28

    Understanding of flow patterns and their transitions is significant to uncover the flow mechanics of two-phase flow. The local phase distribution and its fluctuations contain rich information regarding the flow structures. A wire-mesh sensor (WMS) was used to study the local phase fluctuations of horizontal gas-liquid two-phase flow, which was verified through comparing the reconstructed three-dimensional flow structure with photographs taken during the experiments. Each crossing point of the WMS is treated as a node, so the measurement on each node is the phase fraction in this local area. An undirected and unweighted flow pattern network was established based on connections that are formed by cross-correlating the time series of each node under different flow patterns. The structure of the flow pattern network reveals the relationship of the phase fluctuations at each node during flow pattern transition, which is then quantified by introducing the topological index of the complex network. The proposed analysis method using the WMS not only provides three-dimensional visualizations of the gas-liquid two-phase flow, but is also a thorough analysis for the structure of flow patterns and the characteristics of flow pattern transition. This article is part of the themed issue 'Supersensing through industrial process tomography'.

  14. A New Method for Ultrasound Detection of Interfacial Position in Gas-Liquid Two-Phase Flow

    PubMed Central

    Coutinho, Fábio Rizental; Ofuchi, César Yutaka; de Arruda, Lúcia Valéria Ramos; Jr., Flávio Neves; Morales, Rigoberto E. M.

    2014-01-01

    Ultrasonic measurement techniques for velocity estimation are currently widely used in fluid flow studies and applications. An accurate determination of interfacial position in gas-liquid two-phase flows is still an open problem. The quality of this information directly reflects on the accuracy of void fraction measurement, and it provides a means of discriminating velocity information of both phases. The algorithm known as Velocity Matched Spectrum (VM Spectrum) is a velocity estimator that stands out from other methods by returning a spectrum of velocities for each interrogated volume sample. Interface detection of free-rising bubbles in quiescent liquid presents some difficulties for interface detection due to abrupt changes in interface inclination. In this work a method based on velocity spectrum curve shape is used to generate a spatial-temporal mapping, which, after spatial filtering, yields an accurate contour of the air-water interface. It is shown that the proposed technique yields a RMS error between 1.71 and 3.39 and a probability of detection failure and false detection between 0.89% and 11.9% in determining the spatial-temporal gas-liquid interface position in the flow of free rising bubbles in stagnant liquid. This result is valid for both free path and with transducer emitting through a metallic plate or a Plexiglas pipe. PMID:24858961

  15. Rapid removal of nitrobenzene in a three-phase ozone loaded system with gas-liquid-liquid

    USGS Publications Warehouse

    Li, Shiyin; Zhu, Jiangpeng; Wang, Guoxiang; Ni, Lixiao; Zhang, Yong; Green, Christopher T.

    2015-01-01

    This study explores the removal rate of nitrobenzene (NB) using a new gas-liquid-liquid (G-L-L) three-phase ozone loaded system consisting of a gaseous ozone, an aqueous solvent phase, and a fluorinated solvent phase (perfluorodecalin, or FDC). The removal rate of NB was quantified in relation to six factors including 1) initial pH, 2) initial NB dosage, 3) gaseous ozone dosage, 4) free radical scavenger, 5) FDC pre-aerated gaseous ozone, and 6) reuse of FDC. The NB removal rate is positively affected by the first three factors. Compared with the conventional gas-liquid (water) (G-L) two-phase ozonation system, the free radical scavenger (tertiary butyl alcohol) has much less influence on the removal rate of NB in the G-L-L system. The FDC loaded ozone acts as an ozone reservoir and serves as the main reactive phase in the G-L-L three-phase system. The reuse of FDC has little influence on the removal rate of NB. These experimental results suggest that the oxidation efficiency of ozonation in the G-L-L three-phase system is better than that in the conventional G-L two-phase system.

  16. Measurement of Gas-Liquid Two-Phase Flow in Micro-Pipes by a Capacitance Sensor

    PubMed Central

    Ji, Haifeng; Li, Huajun; Huang, Zhiyao; Wang, Baoliang; Li, Haiqing

    2014-01-01

    A capacitance measurement system is developed for the measurement of gas-liquid two-phase flow in glass micro-pipes with inner diameters of 3.96, 2.65 and 1.56 mm, respectively. As a typical flow regime in a micro-pipe two-phase flow system, slug flow is chosen for this investigation. A capacitance sensor is designed and a high-resolution and high-speed capacitance measurement circuit is used to measure the small capacitance signals based on the differential sampling method. The performance and feasibility of the capacitance method are investigated and discussed. The capacitance signal is analyzed, which can reflect the voidage variation of two-phase flow. The gas slug velocity is determined through a cross-correlation technique using two identical capacitance sensors. The simulation and experimental results show that the presented capacitance measurement system is successful. Research work also verifies that the capacitance sensor is an effective method for the measurement of gas liquid two-phase flow parameters in micro-pipes. PMID:25587879

  17. Use of gas liquid chromatography as an adjunct to conventional bacteriological methods in the diagnosis of anaerobic cerebral abscess.

    PubMed

    Pit, S; Jamal, F; Cheah, F K; Abbas, M A

    1991-07-01

    Forty cases of cerebral abscesses were studied prospectively to establish the microbial agents implicated in these cases. Chronic otitis media (14 patients, 35%), congenital heart disease (five patients, 12.5%),a and meningitis (five patients, 12.5%) were among the important predisposing factors. Streptococcus (14 patients, 35%) was the most common causative pre-isolated, the predominant species being Streptococcus milleri (11 patients, 27.5%). Other organisms isolated included Proteus mirabilis in six patients (15%) and Staphylococcus aureus in five patients (12.5%). Anaerobes (12 patients, 30%), predominantly Bacteroides sp. (eight patients, 20%), played an important role in these cases, the majority of which were isolated in mixed cultures. Gas-liquid chromatographic analysis of pus detected the presence of anaerobes in another 11 cases of cerebral abscess, in which cultures of anaerobes were negative. Therefore, gas-liquid chromotography is useful as an adjunct to conventional bacteriological methods in providing a rapid and sensitive means of detecting anaerobes in pus obtained especially from patients who had received antibiotic therapy prior to hospitalization.

  18. Interfacial instability in vertical counter-current gas-liquid film flow: theory, direct numerical simulation and experiment

    NASA Astrophysics Data System (ADS)

    Schmidt, Patrick; Ausner, Ilja; Ó Náraigh, Lennon; Lucquiaud, Mathieu; Valluri, Prashant

    2016-11-01

    The dynamics of vertical counter-current gas-liquid flows are largely determined by interfacial instability, which gives rise to a multitude of complex wave patterns and internal flows. To study the genesis and evolution of the instability in detail, we employ theoretical stability analysis, experiment and a newly developed level set method based in-house solver to carry out direct numerical simulations. Crucial results of these simulations, such as growth rate and phase velocity of interfacial waves, are rigorously compared against linear and weakly nonlinear theory; thereby showing remarkable agreement. The analysis also reveals the spatio-temporal character of the waves, depicting regimes of absolute and convective instability. Complementing the benchmark set by (non-)linear theory, we perform film thickness measurements of a real gas-liquid system (air-silicone oil) by means of a non-intrusive light-induced fluorescence technique to further validate the solver regarding its capability of capturing interfacial dynamics accurately. These measurements are in good agreement with the results of the nonlinear direct numerical simulations with respect to wavelength and wave shape of the most unstable mode.

  19. The Development of a Gas-Liquid Two-Phase Flow Sensor Applicable to CBM Wellbore Annulus.

    PubMed

    Wu, Chuan; Wen, Guojun; Han, Lei; Wu, Xiaoming

    2016-11-18

    The measurement of wellbore annulus gas-liquid two-phase flow in CBM (coalbed methane) wells is of great significance for reasonably developing gas drainage and extraction processes, estimating CBM output, judging the operating conditions of CBM wells and analyzing stratum conditions. Hence, a specially designed sensor is urgently needed for real-time measurement of gas-liquid two-phase flow in CBM wellbore annulus. Existing flow sensors fail to meet the requirements of the operating conditions of CBM wellbore annulus due to such factors as an inapplicable measurement principle, larger size, poor sealability, high installation accuracy, and higher requirements for fluid media. Therefore, based on the principle of a target flowmeter, this paper designs a new two-phase flow sensor that can identify and automatically calibrate different flow patterns of two-phase flows. Upon the successful development of the new flow sensor, lab and field tests were carried out, and the results show that the newly designed sensor, with a measurement accuracy of ±2.5%, can adapt to the operating conditions of CBM wells and is reliable for long-term work.

  20. Use of Gas-Liquid Chromatography to Determine the End Products of Growth of Lactic Acid Bacteria

    PubMed Central

    Thornhill, Patrick J.; Cogan, Timothy M.

    1984-01-01

    A simple gas-liquid chromatographic procedure for analyzing ethanol, acetic acid, acetoin, and racemic and meso-2,3-butylene glycol in broth media is described. Overnight broth cultures were filtered or centrifuged, and the filtrate or supernatant was treated with formic acid to aid separation of volatile fatty acids. Samples were then directly analyzed by gas-liquid chromatography on a 20% Tween 80-Chromosorb W-AW column and propionic acid as an internal standard. A complete analysis took ca. 8 min. The method can be used to distinguish homofermentative from heterofermentative lactic acid bacteria based on the level of ethanol produced and citrate-utilizing from non-citrate-utilizing lactic acid bacteria based on the levels of acetic acid produced. The method also has potential in distinguishing other bacterial fermentations. Of the 13 species of lactic acid bacteria tested, Streptococcus lactis subsp. diacetylactis was the major producer of 2,3-butylene glycol (total range, 0.3 to 3.5 mM), and, except for strain DRC1, both the racemic and meso isomers were produced in approximately equal amounts. PMID:16346562

  1. Integrated CO2 capture-fixation chemistry via interfacial ionic liquid catalyst in laminar gas/liquid flow

    NASA Astrophysics Data System (ADS)

    Vishwakarma, Niraj K.; Singh, Ajay K.; Hwang, Yoon-Ho; Ko, Dong-Hyeon; Kim, Jin-Oh; Babu, A. Giridhar; Kim, Dong-Pyo

    2017-03-01

    Simultaneous capture of carbon dioxide (CO2) and its utilization with subsequent work-up would significantly enhance the competitiveness of CO2-based sustainable chemistry over petroleum-based chemistry. Here we report an interfacial catalytic reaction platform for an integrated autonomous process of simultaneously capturing/fixing CO2 in gas-liquid laminar flow with subsequently providing a work-up step. The continuous-flow microreactor has built-in silicon nanowires (SiNWs) with immobilized ionic liquid catalysts on tips of cone-shaped nanowire bundles. Because of the superamphiphobic SiNWs, a stable gas-liquid interface maintains between liquid flow of organoamines in upper part and gas flow of CO2 in bottom part of channel. The intimate and direct contact of the binary reagents leads to enhanced mass transfer and facilitating reactions. The autonomous integrated platform produces and isolates 2-oxazolidinones and quinazolines-2,4(1H,3H)-diones with 81-97% yields under mild conditions. The platform would enable direct CO2 utilization to produce high-valued specialty chemicals from flue gases without pre-separation and work-up steps.

  2. A Study of Bubble and Slug Gas-Liquid Flow in a Microgravity Environment

    NASA Technical Reports Server (NTRS)

    McQuillen, J.

    2000-01-01

    The influence of gravity on the two-phase flow dynamics is obvious.As the gravity level is reduced,there is a new balance between inertial and interfacial forces, altering the behavior of the flow. In bubbly flow,the absence of drift velocity leads to spherical-shaped bubbles with a rectilinear trajectory.Slug flow is a succession of long bubbles and liquid slug carrying a few bubbles. There is no flow reversal in the thin liquid film as the long bubble and liquid slug pass over the film. Although the flow structure seems to be simpler than in normal gravity conditions,the models developed for the prediction of flow behavior in normal gravity and extended to reduced gravity flow are unable to predict the flow behavior correctly.An additional benefit of conducting studies in microgravity flows is that these studies aide the development of understanding for normal gravity flow behavior by removing the effects of buoyancy on the shape of the interface and density driven shear flows between the gas and the liquid phases. The proposal calls to study specifically the following: 1) The dynamics of isolated bubbles in microgravity liquid flows will be analyzed: Both the dynamics of spherical isolated bubbles and their dispersion by turbulence, their interaction with the pipe wall,the behavior of the bubbles in accelerated or decelerated flows,and the dynamics of isolated cylindrical bubbles, their deformation in accelerated/decelerated flows (in converging or diverging channels), and bubble/bubble interaction. Experiments will consist of the use of Particle Image Velocimetry (PIV) and Laser Doppler Velocimeters (LDV) to study single spherical bubble and single and two cylindrical bubble behavior with respect to their influence on the turbulence of the surrounding liquid and on the wall 2) The dynamics of bubbly and slug flow in microgravity will be analyzed especially for the role of the coalescence in the transition from bubbly to slug flow (effect of fluid properties and

  3. Relation between tropical cyclone heat potential and cyclone intensity in the North Indian Ocean

    NASA Astrophysics Data System (ADS)

    Jangir, B.; Swain, D.; Udaya Bhaskar, T. V. S.

    2016-05-01

    Ocean Heat Content (OHC) plays a significant role in modulating the intensity of Tropical Cyclones (TC) in terms of the oceanic energy available to TCs. TC Heat Potential (TCHP), an estimate of OHC, is thus known to be a useful indicator of TC genesis and intensification. In the present study, we analyze the role of TCHP in intensification of TCs in the North Indian Ocean (NIO) through statistical comparisons between TCHP and Cyclone Intensities (CI). A total of 27 TCs (20 in the Bay of Bengal, and 7 in the Arabian Sea) during the period 2005-2012 have been analyzed using TCHP data from Global Ocean Data Assimilation System (GODAS) model of Indian National Center for Ocean Information Services and cyclone best track data from India Meteorological Department. Out of the 27 cyclones analyzed, 58% (86%) in the Bay (Arabian Sea) have negative correlation and 42% (14%) cyclones have positive correlation between CI and TCHP. On the whole, more than 60% cyclones in the NIO show negative correlations between CI and TCHP. The negative percentage further increases for TCHP leading CI by 24 and 48 hours. Similar trend is also seen with satellite derived TCHP data obtained from National Remote Sensing Center and TC best track data from Joint Typhoon Warming Centre. Hence, it is postulated that TCHP alone need not be the only significant oceanographic parameter, apart from sea surface temperature, responsible for intensification and propagation of TCs in the NIO.

  4. Cyclone separator having boundary layer turbulence control

    DOEpatents

    Krishna, Coimbatore R.; Milau, Julius S.

    1985-01-01

    A cyclone separator including boundary layer turbulence control that is operable to prevent undue build-up of particulate material at selected critical areas on the separator walls, by selectively varying the fluid pressure at those areas to maintain the momentum of the vortex, thereby preventing particulate material from inducing turbulence in the boundary layer of the vortical fluid flow through the separator.

  5. Reanalyzing Tropical Cyclone Intensities with Citizen Scientists

    NASA Astrophysics Data System (ADS)

    Schreck, C. J.; Hennon, C. C.; Knapp, K.; Stevens, S. E.

    2012-12-01

    Tropical cyclones are among the most destructive weather phenomena. Whenever possible, the intensities of these storms have been determined from in situ data or aircraft reconnaissance. More often, however, they are estimated subjectively from satellite data using the Dvorak technique. Heterogeneities are introduced into the historical record with the evolution of operational procedures, personnel, and observing platforms. In some cases, multiple agencies even arrive at different estimates for the same storm. These uncertainties impede our ability to identify the relationship between tropical cyclone intensities and climate change. NOAA's NCDC has produced a 30-year (1979-2008) homogeneous dataset (HURSAT) of tropical cyclone imagery from geostationary satellites. This dataset has the potential to address some of the uncertainties in the recent tropical cyclone record. However, it would take nearly 40 years for a trained expert, working nonstop, to apply the Dvorak technique to all 200,000 images. Harnessing the power of thousands of Citizen Scientists, the same task can be completed in a matter of months. This presentation will explain how the Dvorak technique was adapted for Citizen Scientists, and how their skill will be evaluated relative to the operational analyses by trained experts.

  6. A Simplified Model of Tropical Cyclone Intensification

    NASA Astrophysics Data System (ADS)

    Schubert, W. H.

    2015-12-01

    An axisymmetric model of tropical cyclone intensification is presented. The model is based on Salmon's wave-vortex approximation, which can describe flows with high Rossby number and low Froude number. After introducing an additional approximation designed to filter propagating inertia-gravity waves, the problem is reduced to the prediction of potential vorticity (PV) and the inversion of this PV to obtain the balanced wind and mass fields. This PV prediction/inversion problem is solved analytically for two types of forcing: a two-region model in which there is nonzero forcing in the cyclone core and zero forcing in the far-field; a three-region model in which there is non-zero forcing in both the cyclone core and the eyewall, with zero forcing in the far-field. The solutions of the two-region model provide insight into why tropical cyclones can have long incubation times before rapid intensification and how the size of the mature vortex can be influenced by the size of the initial vortex. The solutions of the three-region model provide insight into the formation of hollow PV structures and the inward movement of angular momentum surfaces across the radius of maximum wind.

  7. Plastic buckling of cylindrical shells

    SciTech Connect

    Bandyopadhyay, K.; Xu, J.; Shteyngart, S.; Eckert, H.

    1994-05-01

    Cylindrical shells exhibit buckling under axial loads at stresses much less than the respective theoretical critical stresses. This is due primarily to the presence of geometrical imperfections even through such imperfections could be very small (e.g., comparable to thickness). Under internal pressure, the shell regains some of its buckling strength. For a relatively large radius-to-tickness ratio and low internal pressure, the effect can be reasonably estimated by an elastic analysis. However, for low radius-to-thickness ratios and greater pressures, the elastic-plastic collapse controls the failure load. In order to quantify the elastic-plastic buckling capacity of cylindrical shells, an analysis program was carried out by use of the computer code BOSOR5 developed by Bushnell of Lockheed Missiles and Space company. The analysis was performed for various radius-to- thickness ratios and imperfection amplitudes. The analysis results are presented in this paper.

  8. GRIPPING DEVICE FOR CYLINDRICAL OBJECTS

    DOEpatents

    Pilger, J.P.

    1964-01-21

    A gripping device is designed for fragile cylindrical objects such as for drawing thin-walled tubes. The gripping is done by multiple jaw members held in position by two sets of slots, one defined by keystone-shaped extensions of the outer shell of the device and the other in a movable sleeve held slidably by the extensions. Forward movement oi the sleeve advances the jaws, thereby exerting a controlled, radial pressure on the object being gripped. (AEC)

  9. Bremsstrahlung from cylindrical beta sources.

    NASA Technical Reports Server (NTRS)

    Harris, D. W.; Silverman, J.

    1972-01-01

    Refined experimental measurements of the bremsstrahlung number and energy fluxes from thick cylindrical sources of several nuclides are presented, dose rates calculated from experimental energy fluxes are compared with theoretical results based on Wyard's thick-target approximation, and experiments are correlated with both thick- and thin-target bremsstrahlung theory to obtain accurate values of bremsstrahlung yields. The data presented should prove useful for the design of radioisotope power supplies, particularly those used in spacecraft and in biological applications.

  10. Solutions of the cylindrical nonlinear Maxwell equations.

    PubMed

    Xiong, Hao; Si, Liu-Gang; Ding, Chunling; Lü, Xin-You; Yang, Xiaoxue; Wu, Ying

    2012-01-01

    Cylindrical nonlinear optics is a burgeoning research area which describes cylindrical electromagnetic wave propagation in nonlinear media. Finding new exact solutions for different types of nonlinearity and inhomogeneity to describe cylindrical electromagnetic wave propagation is of great interest and meaningful for theory and application. This paper gives exact solutions for the cylindrical nonlinear Maxwell equations and presents an interesting connection between the exact solutions for different cylindrical nonlinear Maxwell equations. We also provide some examples and discussion to show the application of the results we obtained. Our results provide the basis for solving complex systems of nonlinearity and inhomogeneity with simple systems.

  11. Extratropical Cyclone in the Southern Ocean

    NASA Technical Reports Server (NTRS)

    2002-01-01

    These images from the Multi-angle Imaging SpectroRadiometer (MISR) portray an occluded extratropical cyclone situated in the Southern Ocean, about 650 kilometers south of the Eyre Peninsula, South Australia. The left-hand image, a true-color view from MISR's nadir (vertical-viewing) camera, shows clouds just south of the Yorke Peninsula and the Murray-Darling river basin in Australia. Retrieved cloud-tracked wind velocities are indicated by the superimposed arrows. The image on the right displays cloud-top heights. Areas where cloud heights could not be retrieved are shown in black. Both the wind vectors and the cloud heights were derived using data from multiple MISR cameras within automated computer processing algorithms. The stereoscopic algorithms used to generate these results are still being refined, and future versions of these products may show modest changes. Extratropical cyclones are the dominant weather system at midlatitudes, and the term is used generically for regional low-pressure systems in the mid- to high-latitudes. In the southern hemisphere, cyclonic rotation is clockwise. These storms obtain their energy from temperature differences between air masses on either side of warm and cold fronts, and their characteristic pattern is of warm and cold fronts radiating out from a migrating low pressure center which forms, deepens, and dissipates as the fronts fold and collapse on each other. The center of this cyclone has started to decay, with the band of cloud to the south most likely representing the main front that was originally connected with the cyclonic circulation. These views were acquired on October 11, 2001, and the large view represents an area of about 380 kilometers x 1900 kilometers. Image courtesy NASA/GSFC/LaRC/JPL, MISR Team.

  12. Extratropical Cyclone in the Southern Ocean

    NASA Technical Reports Server (NTRS)

    2001-01-01

    These images from the Multi-angle Imaging SpectroRadiometer portray an occluded extratropical cyclone situated in the Southern Ocean, about 650 kilometers south of the Eyre Peninsula, South Australia.

    Parts of the Yorke Peninsula and a portion of the Murray-Darling River basin are visible between the clouds near the top of the left-hand image, a true-color view from MISR's nadir(vertical-viewing) camera. Retrieved cloud-tracked wind velocities are indicated by the superimposed arrows. The image on the right displays cloud-top heights. Areas where cloud heights could not be retrieved are shown in black. Both the wind vectors and the cloud heights were derived using data from multiple MISR cameras within automated computer processing algorithms. The stereoscopic algorithms used to generate these results are still being refined, and future versions of these products may show modest changes.

    Extratropical cyclones are the dominant weather system at midlatitudes, and the term is used generically for region allow-pressure systems in the mid- to high-latitudes. In the southern hemisphere, cyclonic rotation is clockwise. These storms obtain their energy from temperature differences between air masses on either side of warm and cold fronts, and their characteristic pattern is of warm and cold fronts radiating out from a migrating low pressure center which forms, deepens, and dissipates as the fronts fold and collapse on each other. The center of this cyclone has started to decay, with the band of cloud to the south most likely representing the main front that was originally connected with the cyclonic circulation.

    These views were acquired on October 11, 2001 during Terra orbit 9650, and represent an area of about 380 kilometers x 1900 kilometers.

  13. Cylindrical Piezoelectric Fiber Composite Actuators

    NASA Technical Reports Server (NTRS)

    Allison, Sidney G.; Shams, Qamar A.; Fox, Robert L.

    2008-01-01

    The use of piezoelectric devices has become widespread since Pierre and Jacques Curie discovered the piezoelectric effect in 1880. Examples of current applications of piezoelectric devices include ultrasonic transducers, micro-positioning devices, buzzers, strain sensors, and clocks. The invention of such lightweight, relatively inexpensive piezoceramic-fiber-composite actuators as macro fiber composite (MFC) actuators has made it possible to obtain strains and displacements greater than those that could be generated by prior actuators based on monolithic piezoceramic sheet materials. MFC actuators are flat, flexible actuators designed for bonding to structures to apply or detect strains. Bonding multiple layers of MFC actuators together could increase force capability, but not strain or displacement capability. Cylindrical piezoelectric fiber composite (CPFC) actuators have been invented as alternatives to MFC actuators for applications in which greater forces and/or strains or displacements may be required. In essence, a CPFC actuator is an MFC or other piezoceramic fiber composite actuator fabricated in a cylindrical instead of its conventional flat shape. Cylindrical is used here in the general sense, encompassing shapes that can have circular, elliptical, rectangular or other cross-sectional shapes in the planes perpendicular to their longitudinal axes.

  14. Multiphase Transport in Porous Media: Gas-Liquid Separation Using Capillary Pressure Gradients International Space Station (ISS) Flight Experiment Development

    NASA Technical Reports Server (NTRS)

    Wheeler, Richard R., Jr.; Holtsnider, John T.; Dahl, Roger W.; Deeks, Dalton; Javanovic, Goran N.; Parker, James M.; Ehlert, Jim

    2013-01-01

    Advances in the understanding of multiphase flow characteristics under variable gravity conditions will ultimately lead to improved and as of yet unknown process designs for advanced space missions. Such novel processes will be of paramount importance to the success of future manned space exploration as we venture into our solar system and beyond. In addition, because of the ubiquitous nature and vital importance of biological and environmental processes involving airwater mixtures, knowledge gained about fundamental interactions and the governing properties of these mixtures will clearly benefit the quality of life here on our home planet. The techniques addressed in the current research involving multiphase transport in porous media and gas-liquid phase separation using capillary pressure gradients are also a logical candidate for a future International Space Station (ISS) flight experiment. Importantly, the novel and potentially very accurate Lattice-Boltzmann (LB) modeling of multiphase transport in porous media developed in this work offers significantly improved predictions of real world fluid physics phenomena, thereby promoting advanced process designs for both space and terrestrial applications.This 3-year research effort has culminated in the design and testing of a zero-g demonstration prototype. Both the hydrophilic (glass) and hydrophobic (Teflon) media Capillary Pressure Gradient (CPG) cartridges prepared during the second years work were evaluated. Results obtained from ground testing at 1-g were compared to those obtained at reduced gravities spanning Martian (13-g), Lunar (16-g) and zero-g. These comparisons clearly demonstrate the relative strength of the CPG phenomena and the efficacy of its application to meet NASAs unique gas-liquid separation (GLS) requirements in non-terrestrial environments.LB modeling software, developed concurrently with the zero-g test effort, was shown to accurately reproduce observed CPG driven gas-liquid separation

  15. Determination of hexachloro-1,3-butadiene in spinach, eggs, fish, and milk by electron capture gas-liquid chromatography.

    PubMed

    Yurawecz, M P; Dreifuss, P A; Kamps, L R

    1976-05-01

    Hexachloro-1,3-butadiene (HCBD), a waste product formed in the manufacture of perchloroethylene and trichloroethylene, has been found in fish from the lower Mississippi River basin. The AOAC official method for organochlorine pesticide residues in fatty and nonfatty foods has been modified for the determination of HCBD residues in selected food commodities. Acetonitrile extracts of nonfatty foods, or the combined acetonitrile extracts obtained in acetonitrile-petroleum ether partitioning of fat isolated from fatty foods, are diluted with water and extracted with petroleum ether. The petroleum ether extracts are chromatographed on Florisil and HCBD is eluted with petroleum ether. The elute is analyzed by gas-liquid chromatography with an electron capture detector. Average recoveries of HCBD from fortified samples of fatty and nonfatty foods were greater than 90% in the interlaboratory trials of the method.

  16. Mathematical Simulation of Unsteady-State Gas-Liquid Mixture Flow in a Bed-Well System

    NASA Astrophysics Data System (ADS)

    Abbasov, É. M.; Imamaliev, S. A.

    2016-09-01

    Based on theoretical investigations, the influence of various forms of pressure variation at the wellhead with a nonstationary flow of a two-phase fluid in a bed-well system on the character of change in the bottom-hole pressure has been investigated, which makes it possible to determine this pressure from the wellhead operation parameters. The trapezoidal form of the change in pressure is considered as an example. The coupled equations of filtration and the equations describing nonstationary motion of a gas-liquid mixture in a pipeline have been solved jointly. Analytical formulas have been obtained allowing one to determine the bottom-hole pressure from the technological parameters at the wellhead with account for the dynamic connection of the bed-well system at different forms of change in the wellhead pressure. The influence of the wellhead pressure pulsation frequencies on the bottom-hole pressure dynamics has been established.

  17. Theoretical and experimental analysis of a multiphase screw pump, handling gas-liquid mixtures with very high gas volume fractions

    SciTech Connect

    Raebiger, K.; Maksoud, T.M.A.; Ward, J.; Hausmann, G.

    2008-09-15

    In the investigation of the pumping behaviour of multiphase screw pumps, handling gas-liquid mixtures with very high gas volume fractions, theoretical and experimental analyses were performed. A new theoretical screw pump model was developed, which calculates the time-dependent conditions inside the several chambers of a screw pump as well as the exchange of mass and energy between these chambers. By means of the performed experimental analysis, the screw pump model was verified, especially at very high gas volume fractions from 90% to 99%. The experiments, which were conducted with the reference fluids water and air, can be divided mainly into the determination of the steady state pumping behaviour on the one hand and into the analysis of selected transient operating conditions on the other hand, whereas the visualisation of the leakage flows through the circumferential gaps was rounded off the experimental analysis. (author)

  18. Optical and application study of gas-liquid discharge excited by bipolar nanosecond pulse in atmospheric air

    NASA Astrophysics Data System (ADS)

    Wang, Sen; Wang, Wen-chun; Yang, De-zheng; Liu, Zhi-jie; Zhang, Shuai

    2014-10-01

    In this study, a bipolar nanosecond pulse with 20 ns rising time is employed to generate air gas-liquid diffuse discharge plasma with room gas temperature in quartz tube at atmospheric pressure. The image of the discharge and optical emission spectra of active species in the plasma are recorded. The plasma gas temperature is determined to be approximately 390 K by compared the experimental spectra with the simulated spectra, which is slightly higher than the room temperature. The result indicated that the gas temperature rises gradually with pulse peak voltage increasing, while decreases slightly with the electrode gap distance increasing. As an important application, bipolar nanosecond pulse discharge is used to sterilize the common microorganisms (Actinomycetes, Candida albicans and Escherichia coli) existing in drinking water, which performs high sterilization efficiency.

  19. Slug front gas entrainment in gas-liquid two-phase horizontal flow using hi-speed slug-tracking

    NASA Astrophysics Data System (ADS)

    Zadrazil, Ivan; Matar, Omar; Markides, Christos

    2013-11-01

    A gas-liquid flow regime where liquid-continuous regions travel at high speeds (i.e. slugs) through a pipe separated by regions of stratified flow (i.e. elongated bubbles) is referred to as a ``slug flow.'' This regime is characterised by the turbulent entrainment of gas into the slug front body. We use a high-speed camera mounted on a moving robotic linear rail to track the formation of naturally occurring slugs over 150 pipe diameters. We show that the dynamics of the slugs become progressively more complex with increasing liquid and gas Reynolds numbers. Based on the slug-tracking visualization we present, over a range of conditions: (i) phenomenological observations of the formation and development of slugs, and (ii) statistical data on the slug velocity and gas entrainment rate into the slug body. EPSRC Programme Grant EP/K003976/1.

  20. Exergy destruction analysis of a vortices generator in a gas liquid finned tube heat exchanger: an experimental study

    NASA Astrophysics Data System (ADS)

    Ghazikhani, M.; Khazaee, I.; Monazzam, S. M. S.; Takdehghan, H.

    2016-11-01

    In the present work, the effect of using different shapes of vortices generator (VG) on a gas liquid finned heat exchanger is investigated experimentally with irreversibility analysis. In this project the ambient air with mass flow rates of 0.047-0.072 kg/s is forced across the finned tube heat exchanger. Hot water with constant flow rate of 240 L/h is circulated inside heat exchanger tubes with inlet temperature range of 45-73 °C. The tests are carried out on the flat finned heat exchanger and then repeated on the VG finned heat exchanger. The results show that using the vortex generator can decrease the ratio of air side irreversibility to heat transfer (ASIHR) of the heat exchanger. Also the results show that the IASIHR is >1.05 for all air mass flow rates, which means that ASIHR for the initial heat exchanger is higher than 5 % greater than that of improved heat exchanger.

  1. [CFD numerical simulation onto the gas-liquid two-phase flow behavior during vehicle refueling process].

    PubMed

    Chen, Jia-Qing; Zhang, Nan; Wang, Jin-Hui; Zhu, Ling; Shang, Chao

    2011-12-01

    With the gradual improvement of environmental regulations, more and more attentions are attracted to the vapor emissions during the process of vehicle refueling. Research onto the vehicle refueling process by means of numerical simulation has been executed abroad since 1990s, while as it has never been involved so far domestically. Through reasonable simplification about the physical system of "Nozzle + filler pipe + gasoline storage tank + vent pipe" for vehicle refueling, and by means of volume of fluid (VOF) model for gas-liquid two-phase flow and Re-Normalization Group kappa-epsilon turbulence flow model provided in commercial computational fluid dynamics (CFD) software Fluent, this paper determined the proper mesh discretization scheme and applied the proper boundary conditions based on the Gambit software, then established the reasonable numerical simulation model for the gas-liquid two-phase flow during the refueling process. Through discussing the influence of refueling velocity on the static pressure of vent space in gasoline tank, the back-flowing phenomenon has been revealed in this paper. It has been demonstrated that, the more the flow rate and the refueling velocity of refueling nozzle is, the higher the gross static pressure in the vent space of gasoline tank. In the meanwhile, the variation of static pressure in the vent space of gasoline tank can be categorized into three obvious stages. When the refueling flow rate becomes higher, the back-flowing phenomenon of liquid gasoline can sometimes be induced in the head section of filler pipe, thus making the gasoline nozzle pre-shut-off. Totally speaking, the theoretical work accomplished in this paper laid some solid foundation for self-researching and self-developing the technology and apparatus for the vehicle refueling and refueling emissions control domestically.

  2. A New Void Fraction Measurement Method for Gas-Liquid Two-Phase Flow in Small Channels

    PubMed Central

    Li, Huajun; Ji, Haifeng; Huang, Zhiyao; Wang, Baoliang; Li, Haiqing; Wu, Guohua

    2016-01-01

    Based on a laser diode, a 12 × 6 photodiode array sensor, and machine learning techniques, a new void fraction measurement method for gas-liquid two-phase flow in small channels is proposed. To overcome the influence of flow pattern on the void fraction measurement, the flow pattern of the two-phase flow is firstly identified by Fisher Discriminant Analysis (FDA). Then, according to the identification result, a relevant void fraction measurement model which is developed by Support Vector Machine (SVM) is selected to implement the void fraction measurement. A void fraction measurement system for the two-phase flow is developed and experiments are carried out in four different small channels. Four typical flow patterns (including bubble flow, slug flow, stratified flow and annular flow) are investigated. The experimental results show that the development of the measurement system is successful. The proposed void fraction measurement method is effective and the void fraction measurement accuracy is satisfactory. Compared with the conventional laser measurement systems using standard laser sources, the developed measurement system has the advantages of low cost and simple structure. Compared with the conventional void fraction measurement methods, the proposed method overcomes the influence of flow pattern on the void fraction measurement. This work also provides a good example of using low-cost laser diode as a competent replacement of the expensive standard laser source and hence implementing the parameter measurement of gas-liquid two-phase flow. The research results can be a useful reference for other researchers’ works. PMID:26828488

  3. Can climate models represent the precipitation associated with extratropical cyclones?

    NASA Astrophysics Data System (ADS)

    Hawcroft, Matthew K.; Shaffrey, Len C.; Hodges, Kevin I.; Dacre, Helen F.

    2016-08-01

    Extratropical cyclones produce the majority of precipitation in many regions of the extratropics. This study evaluates the ability of a climate model, HiGEM, to reproduce the precipitation associated with extratropical cyclones. The model is evaluated using the ERA-Interim reanalysis and GPCP dataset. The analysis employs a cyclone centred compositing technique, evaluates composites across a range of geographical areas and cyclone intensities and also investigates the ability of the model to reproduce the climatological distribution of cyclone associated precipitation across the Northern Hemisphere. Using this phenomena centred approach provides an ability to identify the processes which are responsible for climatological biases in the model. Composite precipitation intensities are found to be comparable when all cyclones across the Northern Hemisphere are included. When the cyclones are filtered by region or intensity, differences are found, in particular, HiGEM produces too much precipitation in its most intense cyclones relative to ERA-Interim and GPCP. Biases in the climatological distribution of cyclone associated precipitation are also found, with biases around the storm track regions associated with both the number of cyclones in HiGEM and also their average precipitation intensity. These results have implications for the reliability of future projections of extratropical precipitation from the model.

  4. Case studies of EUV cyclones and their associated magnetic fields

    NASA Astrophysics Data System (ADS)

    Yu, Xin-Ting; Zhang, Jun; Li, Ting; Yang, Shu-Hong

    2015-09-01

    EUV cyclones are rotating structures in the solar corona, and they are usually rooted in the underlying rotating network magnetic fields in the photosphere. However, their connection with the surrounding magnetic fields remains unknown. Here we report an observational study of four typical cyclones which are rooted in different kinds of magnetic fields. We use Solar Dynamics Observatory/Atmospheric Imaging Assembly data to investigate the rotation of EUV features in cyclones and Helioseismic and Magnetic Imager data to study the associated magnetic fields. The results show that, (1) an EUV cyclone rooted in a sunspot rotates with the photospheric magnetic field; (2) two EUV cyclones in two faculae of an active region are connected to the same sunspot of the active region but rotate oppositely; (3) an EUV cyclone is rooted in a coronal hole with weak open magnetic fields; (4) a pair of conjugated cyclones is rooted in magnetic fields that have opposite polarity with opposite directions of rotation. The differences in the spatial extent of a cyclone, characteristics of its rotation and underlying fields indicate that cyclones are ubiquitous over the solar atmosphere and that the magnetic structures relevant to the cyclones are more complicated than expected.

  5. Remote, real-time monitoring of cyclones with microseisms

    NASA Astrophysics Data System (ADS)

    Jo, B. G.; Lee, W. D.; Schwab, F. A.

    2014-12-01

    Giving proper care to selecting microseisms from well isolated cyclones, these great oceanic storms can be monitored in real time by seismic recordings at stations 1200-4100 km distant from the cyclone's center. We treat ocean depths of 3.4-5.5 km. For the theoretically-computed microseism, which our procedure compares with the experimental data, we use a Green's-function approach in the frequency domain. Relating recorded displacement F and theoretical Green's function G, We have F(ω,r)=S(ω)G(ω,r) in which our only unknown is the generalized source function S(ω) and r is the distance to the center at any specific time. The basic result of this report is that the form of this function is A SN(ω), where A is a real constant increasing with the strength of the cyclone and SN(ω), is a positive real function of frequency, independent of cyclone-receiver separation and of cyclone strength. That is, for a given ocean basin, and a given receiver-region geology, at our current level of accuracy SN(ω) is the same for all cyclone strengths and cyclone-receiver separations. Using the multimode approach, we've developed the numerical method for computing the Green's function for multilayered oceanic structures. For each of the 4 selected cyclones, the source functions for all locations along the path show a consistency which demonstrates that the recorded microseisms are radiated from the cyclone. The extracted source function exhibits spectra that are characteristic of ocean waves generated by cyclonic winds. With knowledge of distance between the source and receiver, cyclone A is therefore trivial to monitor in real time from remote recordings. At the current time, the cyclone's strength—generalized source function—must be related empirically to the cyclone's maximum wind speed, areal extent, and lateral velocity.

  6. Tropical Cyclone Interactions Within Central American Gyres

    NASA Astrophysics Data System (ADS)

    Papin, P. P.; Bosart, L. F.; Torn, R. D.

    2014-12-01

    Central American gyres (CAGs) are broad (~1000 km diameter) low-level cyclonic circulations that organize over Central America during the tropical cyclone (TC) season. While CAGs have rarely been studied, prior work on similar circulations has been conducted on monsoon depressions (MDs) and monsoon gyres (MGs), which possess spatial scales of 1000 - 2500 km in the west Pacific basin. A key difference between MDs and MGs is related to the organization of vorticity around the low-level circulation. MDs possess a symmetrical vorticity pattern where vorticity accumulates near the circulation center over time, occasionally developing into a large TC. In contrast, MGs possess asymmetrical vorticity, organized in mesovorticies, which rotate cyclonically along the periphery of the MG circulation. Small tropical cyclones (TCs) occasionally develop from these mesovorticies. Interaction and development of TCs within CAGs are also common, as noted by a CAG identified during the 2010 PREDICT field project, which involved the interaction of TC Matthew and the development of TC Nicole within the larger CAG. This project is motivated by the lack of prior research on CAGs, as well as the complex scale interactions that occasionally occur between TCs and CAGs. This presentation focuses on the mutual interaction of vortices embedded in the larger-scale cyclonic flow comprising the CAG circulation. Case studies will be presented using a circulation framework to illustrate the relationship between different scale vorticity elements within the CAG. Some of these case studies resemble a MD-like evolution, where a large TC develops through the accumulation of symmetrical vorticity around the CAG (e.g. TC Opal 1995, TC Frances 1998). Other instances resemble a MG-like evolution, where smaller mesovorticies rotate around a common circulation center (e.g. TC Florence 1988). The circulation analysis framework aids in the diagnosis of interaction between different scale cyclonic vortices, and

  7. Nonthermal inactivation of Escherichia coli K12 in buffered peptone water using a pilot-plant scale supercritical carbon dioxide system with gas-liquid porous metal contractor

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study evaluated the effectiveness of a supercritical carbon dioxide (SCCO2) system, with a gas-liquid CO2 contactor, for reducing Escherichia coli K12 in diluted buffered peptone water. 0.1% (w/v) buffered peptone water inoculated with E. coli K12 was processed using the SCCO2 system at CO2 con...

  8. ARSENIC DETERMINATION IN SALINE WATERS UTILIZING A TUBULAR MEMBRANE AS A GAS-LIQUID SEPATRATOR FOR HYDRIDE GENERATION INDUCTIVELY COUPLED PLASMA MASS SPECTROMETRY

    EPA Science Inventory

    A tubular silicone rubber membrane is evaluated as a gas-liquid separator for the determination of arsenic in saline waters via HG-ICP-MS. The system was optimized in terms of NaBH and HCI concentrations. The intermediate gas and carrier gas were optimized in terms of sensitiity ...

  9. Space options for tropical cyclone hazard mitigation

    NASA Astrophysics Data System (ADS)

    Dicaire, Isabelle; Nakamura, Ryoko; Arikawa, Yoshihisa; Okada, Kazuyuki; Itahashi, Takamasa; Summerer, Leopold

    2015-02-01

    This paper investigates potential space options for mitigating the impact of tropical cyclones on cities and civilians. Ground-based techniques combined with space-based remote sensing instrumentation are presented together with space-borne concepts employing space solar power technology. Two space-borne mitigation options are considered: atmospheric warming based on microwave irradiation and laser-induced cloud seeding based on laser power transfer. Finally technology roadmaps dedicated to the space-borne options are presented, including a detailed discussion on the technological viability and technology readiness level of our proposed systems. Based on these assessments, the space-borne cyclone mitigation options presented in this paper may be established in a quarter of a century.

  10. Submesoscale cyclones in the Agulhas current

    NASA Astrophysics Data System (ADS)

    Krug, M.; Swart, S.; Gula, J.

    2017-01-01

    Gliders were deployed for the first time in the Agulhas Current region to investigate processes of interactions between western boundary currents and shelf waters. Continuous observations from the gliders in water depths of 100-1000 m and over a period of 1 month provide the first high-resolution observations of the Agulhas Current's inshore front. The observations collected in a nonmeandering Agulhas Current show the presence of submesoscale cyclonic eddies, generated at the inshore boundary of the Agulhas Current. The submesoscale cyclones are often associated with warm water plumes, which extend from their western edge and exhibit strong northeastward currents. These features are a result of shear instabilities and extract their energy from the mean Agulhas Current jet.

  11. Tropical cyclone rainfall area controlled by relative sea surface temperature

    PubMed Central

    Lin, Yanluan; Zhao, Ming; Zhang, Minghua

    2015-01-01

    Tropical cyclone rainfall rates have been projected to increase in a warmer climate. The area coverage of tropical cyclones influences their impact on human lives, yet little is known about how tropical cyclone rainfall area will change in the future. Here, using satellite data and global atmospheric model simulations, we show that tropical cyclone rainfall area is controlled primarily by its environmental sea surface temperature (SST) relative to the tropical mean SST (that is, the relative SST), while rainfall rate increases with increasing absolute SST. Our result is consistent with previous numerical simulations that indicated tight relationships between tropical cyclone size and mid-tropospheric relative humidity. Global statistics of tropical cyclone rainfall area are not expected to change markedly under a warmer climate provided that SST change is relatively uniform, implying that increases in total rainfall will be confined to similar size domains with higher rainfall rates. PMID:25761457

  12. Associating extreme precipitation events to parent cyclones in gridded data

    NASA Astrophysics Data System (ADS)

    Rhodes, Ruari; Shaffrey, Len; Gray, Sue

    2015-04-01

    When analysing the relationship of regional precipitation to its parent cyclone, it is insufficient to consider the cyclone's region of influence as a fixed radius from the centre due to the irregular shape of rain bands. A new method is therefore presented which allows the use of objective feature tracking data in the analysis of regional precipitation. Utilising the spatial extent of precipitation in gridded datasets, the most appropriate cyclone(s) may be associated with regional precipitation events. This method is applied in the context of an analysis of the influence of clustering and stalling of extra-tropical cyclones in the North Atlantic on total precipitation accumulations over England and Wales. Cyclone counts and residence times are presented for historical records (ERA-Interim) and future projections (HadGEM2-ES) of extreme (> 98th percentile) precipitation accumulations over England and Wales, for accumulation periods ranging from one day to one month.

  13. Internal Influences on Tropical Cyclone Formation

    DTIC Science & Technology

    2006-01-01

    scales. This is evident in Fig. 2. Another hypothesis in the top-down category is what we call the “ shower - head” theory by Bister and Emanuel...extra-tropical precursors. Quart. J. Roy. Meteor . Soc. (coming soon). Dickinson, M.J., and J. Molinari, 2002: Mixed Rossby-gravity waves and...1998: The formation of Tropical Cyclones. Meteor . Atmos. Phys. 67, 37—69. Harr, P. A., M. S. Kalafsky and R. L. Elsberry, 1996a: Environmental

  14. Objective classification of historical tropical cyclone intensity

    NASA Astrophysics Data System (ADS)

    Chenoweth, Michael

    2007-03-01

    Preinstrumental records of historical tropical cyclone activity require objective methods for accurately categorizing tropical cyclone intensity. Here wind force terms and damage reports from newspaper accounts in the Lesser Antilles and Jamaica for the period 1795-1879 are compared with wind speed estimates calculated from barometric pressure data. A total of 95 separate barometric pressure readings and colocated simultaneous wind force descriptors and wind-induced damage reports are compared. The wind speed estimates from barometric pressure data are taken as the most reliable and serve as a standard to compare against other data. Wind-induced damage reports are used to produce an estimated wind speed range using a modified Fujita scale. Wind force terms are compared with the barometric pressure data to determine if a gale, as used in the contemporary newspapers, is consistent with the modern definition of a gale. Results indicate that the modern definition of a gale (the threshold point separating the classification of a tropical depression from a tropical storm) is equivalent to that in contemporary newspaper accounts. Barometric pressure values are consistent with both reported wind force terms and wind damage on land when the location, speed and direction of movement of the tropical cyclone are determined. Damage reports and derived wind force estimates are consistent with other published results. Biases in ships' logbooks are confirmed and wind force terms of gale strength or greater are identified. These results offer a bridge between the earlier noninstrumental records of tropical cyclones and modern records thereby offering a method of consistently classifying storms in the Caribbean region into tropical depressions, tropical storms, nonmajor and major hurricanes.

  15. Next-Generation Tropical Cyclone Model

    DTIC Science & Technology

    2016-06-07

    goal of this project is to develop a robust and hardened high-resolution air- ocean coupled tropical cyclone (TC) data assimilation and prediction...mechanical interchanges with the underlying ocean and land surfaces, shallow and deep atmospheric convection in the convectively unstable tropical...shown to be able to reproduce rapid intensification in case studies involving complex upper tropospheric and oceanic conditions in a carefully

  16. Loads for pulsed power cylindrical implosion experiments

    SciTech Connect

    Anderson, W.E.; Armijo, E.V.; Barthell, B.L.; Bartos, J.J.; Bush, H.; Foreman, L.R.; Garcia, F.P.; Gobby, P.L.; Gomez, V.M.; Gurule, V.A.

    1994-07-01

    Pulse power can be used to generate high energy density conditions in convergent hollow cylindrical geometry through the use of appropriate electrode configuration and cylindrical loads. Cylindrically symmetric experiments are conducted with the Pegasus-H inductive store, capacitor energized pulse power facility at Los Alamos using both precision machined cylindrical liner loads and low mass vapor deposited cylindrical foil loads. The liner experiments investigate solid density hydrodynamic topics. Foil loads vaporize from Joule heating to generate an imploding cylindrical plasma which can be used to simulate some fluxes associated with fusion energy processes. Similar experiments are conducted with {open_quotes}Procyon{close_quotes} inductive store pulse power assemblies energized by explosively driven magnetic flux compression.

  17. Thermoconvective vortices in a cylindrical annulus with varying inner radius.

    PubMed

    Castaño, D; Navarro, M C; Herrero, H

    2014-12-01

    This paper shows the influence of the inner radius on the stability and intensity of vertical vortices, qualitatively similar to dust devils and cyclones, generated in a cylindrical annulus non-homogeneously heated from below. Little relation is found between the intensity of the vortex and the magnitude of the inner radius. Strong stable vortices can be found for both small and large values of the inner radius. The Rankine combined vortex structure, that characterizes the tangential velocity in dust devils, is clearly observed when small values of the inner radius and large values of the ratio between the horizontal and vertical temperature differences are considered. A contraction on the radius of maximum azimuthal velocity is observed when the vortex is intensified by thermal mechanisms. This radius becomes then nearly stationary when frictional force balances the radial inflow generated by the pressure drop in the center, despite the vortex keeps intensifying. These results connect with the behavior of the radius of the maximum tangential wind associated with a hurricane.

  18. Thermoconvective vortices in a cylindrical annulus with varying inner radius

    NASA Astrophysics Data System (ADS)

    Castaño, D.; Navarro, M. C.; Herrero, H.

    2014-12-01

    This paper shows the influence of the inner radius on the stability and intensity of vertical vortices, qualitatively similar to dust devils and cyclones, generated in a cylindrical annulus non-homogeneously heated from below. Little relation is found between the intensity of the vortex and the magnitude of the inner radius. Strong stable vortices can be found for both small and large values of the inner radius. The Rankine combined vortex structure, that characterizes the tangential velocity in dust devils, is clearly observed when small values of the inner radius and large values of the ratio between the horizontal and vertical temperature differences are considered. A contraction on the radius of maximum azimuthal velocity is observed when the vortex is intensified by thermal mechanisms. This radius becomes then nearly stationary when frictional force balances the radial inflow generated by the pressure drop in the center, despite the vortex keeps intensifying. These results connect with the behavior of the radius of the maximum tangential wind associated with a hurricane.

  19. Les cyclones tropicaux et le changement climatique

    NASA Astrophysics Data System (ADS)

    André, Jean-Claude; Royer, Jean-François; Chauvin, Fabrice

    2008-09-01

    Results from observations and modelling studies, a number of which having been used to support the conclusions of the IPCC fourth assessment report, are presented. For the past and present-day (since 1970) periods, the increase of strong cyclonic activity over the North Atlantic Ocean appears to be in good correlation with increasing temperature of the ocean surface. For regions where observational data are of lesser quality, the increasing trend is less clear. In fact, assessing long-term changes is made difficult due to both the multi-decennial natural variability and the lesser coverage of observations before satellites were made available. Indirect observational data, such as those derived from quantitative estimations of damage caused by tropical cyclones, suffer from many artefacts and do not allow the resolving of the issue either. For the future, only numerical three-dimensional climate models can be used. They nevertheless run presently with too-large grid-sizes, so that their results are still not converging. Various simulations lead indeed to different results, and it is very often difficult to find the physical reasons for these differences. One concludes by indicating some ways through which numerical simulations could be improved, leading to a decrease of uncertainties affecting the prediction of cyclonic activity over the next decades.

  20. DETAIL OF CYCLONE CLASSIFIER, WITH MARCY NO. 86 BALL MILL ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL OF CYCLONE CLASSIFIER, WITH MARCY NO. 86 BALL MILL BELOW AND BEHIND IT. STRAIGHT HORIZONTAL PIPE IS SLIME FEED FROM ROD MILL. PIPE OUT TOP OF CYCLONE AND CURVING AT LOWER RIGHT CARRIED FINELY GROUND SLIME TO FLOTATION CONDITIONER TANK. PIPE NOT VISIBLE OUT BOTTOM OF CYCLONE CONVEYED COARSER SLIME TO BALL MILL. - Shenandoah-Dives Mill, 135 County Road 2, Silverton, San Juan County, CO

  1. Precipitation of suspended particles in wet-film cyclones

    SciTech Connect

    Val'dberg, A.Y.; Kirsanova, N.S.

    1986-07-01

    The fact that wet and dry mechanical centrifugal dust collectors operate on the same principle allowed the authors to make the calculations for wet cyclones with an equation similar to one used previously. A figure shows that the efficiency of wet cyclones is much higher (20% higher on the average) than that of dry cyclones under the same operating conditions. This improvement is due to a decrease in the secondary discharge of dust particles from the wet wall of the device.

  2. Incorporation of Tropical Cyclone Avoidance Into Automated Ship Scheduling

    DTIC Science & Technology

    2014-06-01

    TROPICAL CYCLONE AVOIDANCE INTO AUTOMATED SHIP SCHEDULING by Stephen W. Lantz June 2014 Thesis Advisor: Walter DeGrange Co-Advisor: Eva...COVERED Master’s Thesis 4. TITLE AND SUBTITLE INCORPORATION OF TROPICAL CYCLONE AVOIDANCE INTO AUTOMATED SHIP SCHEDULING 5. FUNDING NUMBERS 6... cyclones (TCs) frequently disrupt these plans, requiring diversions and inefficient steaming speeds. We evaluate the impact of adding anticipated TC

  3. Evolution of Tropical Cyclone Characteristics and Forecast Assessment

    DTIC Science & Technology

    2016-06-07

    structure, which is important to understanding the motion of the tropical cyclone, is dependent on the growth, evolution, and decay of mesoscale convective ...MCS structural characteristics such as convective and stratiform cloud amounts, percent coverage, and rain rates. Furthermore, co- located microwave...tropical cyclone features (e.g., convective activity, inner-core structure), midlatitude circulation into which the tropical cyclone is moving, and

  4. The Effect of Vertical Wind Shear on Tropical Cyclone Movement

    DTIC Science & Technology

    1988-01-01

    by Sanders and Burpee (1968), is a one-layer model which uses the barotropic vorticity equation to forecast the vertically averaged vorticity field...of factors which could modify cyclone movement. With the advent of numerical predication methods, it became possible to test these concepts. Numerical...conditions to test the cyclone features, are also presented. Chapter 3 investigates the effects of the physical processes on tropical cyclone movement by

  5. The Calculated Ratio of the Gas Flow in a Countercurrent Cyclone Dust Concentrator

    NASA Astrophysics Data System (ADS)

    Vasilevsky, Michail; Razva, Aleksandr; Pleschko, Alissa; Kadurkin, Ivan

    2016-02-01

    There are numerous studies of the structure of swirling flow in a variety of devices in which the peculiarities of the parameters associated with the twist flow. The values of the local parameters of the twist of the axial direction are experimentally and connect them with a constructive twist parameter, which is built from the idealized repose of the gas flow in vortex distribution and speed at the exit of the swirl. For counter flow chamber is the equation for the input pulse in the radial direction and the twist parameter is provided in the radial direction. It allows us to estimate the maximum radius of the circumferential velocity not only near the outlet, but also near the end surface of the chamber. On a cylindrical surface with a radius of outlet cyclone tangential turbulent friction in the radial direction depends on the product of a circle and radial speeds. Compiled equation changes the flow of angular momentum in the axial zone, depending on the force of friction tangential flow on the surface with the radius of the outlet pipe of the cyclone. This equation allowed assessing the circulation of gas in the axial zone.

  6. Evaluation of transmitting performance of cylindrical polycapillary

    NASA Astrophysics Data System (ADS)

    Xiaoyan, Lin; Yude, Li; Guotai, Tan; Tianxi, Sun

    2007-03-01

    Based on a detailed ray-tracing code for capillary optics, a MATLAB program for the simulation of X-ray transmission in a cylindrical polycapillary is described. The simulated and experimental results for the spatial distributions and power density gain of the X-rays in the beam guided through a cylindrical polycapillary are in good agreement, and the results show that the spatial distribution of the X-rays in the beam guided through a cylindrical polycapillary is uneven.

  7. Cyclone Nargis in Myanmar: lessons for public health preparedness for cyclones.

    PubMed

    Guha-Sapir, Debarati; Vogt, Florian

    2009-01-01

    Recent natural disasters such as the 2004 tsunami, 2008 Sichuan earthquake, and the 2008 Myanmar cyclone have killed more than 100,000 people each. Mortality and morbidity associated with natural disasters are a growing concern, especially because extreme climate events are likely to get increasingly frequent. The authors comment on Cyclone Nargis, claiming an extraordinarily high death toll during its devastating track through the Irrawaddy delta in Myanmar on May 2, 2008 and analyze how and why its mortality pattern differs from other typical postdisaster situations. Underlying factors and preconditions are described and the specificity of the Myanmese context is presented. This leads to lessons how excess mortality can be reduced in future high-ranked cyclones, whose recurrence in this region will only be a matter of time.

  8. Models of cylindrical bubble pulsation

    PubMed Central

    Ilinskii, Yurii A.; Zabolotskaya, Evgenia A.; Hay, Todd A.; Hamilton, Mark F.

    2012-01-01

    Three models are considered for describing the dynamics of a pulsating cylindrical bubble. A linear solution is derived for a cylindrical bubble in an infinite compressible liquid. The solution accounts for losses due to viscosity, heat conduction, and acoustic radiation. It reveals that radiation is the dominant loss mechanism, and that it is 22 times greater than for a spherical bubble of the same radius. The predicted resonance frequency provides a basis of comparison for limiting forms of other models. The second model considered is a commonly used equation in Rayleigh-Plesset form that requires an incompressible liquid to be finite in extent in order for bubble pulsation to occur. The radial extent of the liquid becomes a fitting parameter, and it is found that considerably different values of the parameter are required for modeling inertial motion versus acoustical oscillations. The third model was developed by V. K. Kedrinskii [Hydrodynamics of Explosion (Springer, New York, 2005), pp. 23–26] in the form of the Gilmore equation for compressible liquids of infinite extent. While the correct resonance frequency and loss factor are not recovered from this model in the linear approximation, it provides reasonable agreement with observations of inertial motion. PMID:22978863

  9. Control of fine particulate emissions from coal-fired utility boilers: Spin filter collection device (rotary cyclone)

    SciTech Connect

    He, Bo X.

    1990-01-01

    A bench-scale test program has been performed to evaluate the concept of placing a porous cylindrical surface (such as a metal screen) at the core of a container and spinning the surface with an external motor for fine particulate/gas separation. The rotating surface enhances the centrifugal effects in the annular region and provides a smooth transition between the flow in the annular and core regions and acts like an enhanced cyclone. It is therefore called a rotary cyclone.'' The porous surface is self-cleaning and offers good steady-state pressure drop characteristics. Objectives of this project are: (1) to carry out theoretical and experimental investigations using the rotary cyclone concept to capture particulates in the 0.5 to 10 micron size range; and (2) to evaluate its economic feasibility based on an engineering scale-up and comparison with conventional fabric filter and electrostatic precipitator systems. It was demonstrated that the efficiency in separating fine particulates is governed by two major characteristics, i.e., the magnitude of the centrifugal force and the approach velocity or the gas-to-surface area ratio. Results from the bench-scale tests have shown a collection efficiency of well over 99% for a typical fly ash. A preliminary conceptual design for a 40 MW installation was developed based on the experimental work. 4 refs., 4 figs., 8 tabs.

  10. Animation of Flood Potential from Two Australian Tropical Cyclones

    NASA Video Gallery

    Merged precipitation data from NASA-JAXA's Tropical Rainfall Measuring Mission (TRMM) and other satellites was used to calculate flood potential withrainfall from Tropical Cyclone Lam and Tropical ...

  11. Hydration of the upper troposphere by tropical cyclones

    NASA Astrophysics Data System (ADS)

    Ray, Eric A.; Rosenlof, Karen H.

    2007-06-01

    Tropical cyclones in the Atlantic and Pacific ocean basins are found to have a significant impact on the amount of water vapor in the tropical and subtropical upper troposphere. Measurements from AIRS on Aqua and MLS on Aura are used to reveal details of the water vapor and temperature structure of the upper troposphere in the vicinity of tropical cyclones that have been unavailable from previous satellite observations. These measurements show that the most intense tropical cyclones (categories 4 and 5) increase average water vapor mixing ratios between 300 and 150 hPa in a roughly 1500 km2 area around the cyclones by 10-50% over their lifetimes. Category 3 and weaker tropical cyclones hydrate the upper troposphere on average roughly half as effectively as the most intense cyclones. The most intense cyclones also increase average water vapor in the upper troposphere by 2-10% in the entire ocean basin in which they occur. This amount of hydration of the tropical upper troposphere suggests that tropical cyclones play a role in the water vapor budget, and associated climate feedbacks, in a region much larger than the cyclone vicinity.

  12. Studies of Two-Phase Gas-Liquid Flow in Microgravity. Ph.D. Thesis, Dec. 1994

    NASA Technical Reports Server (NTRS)

    Bousman, William Scott

    1995-01-01

    Two-phase gas-liquid flows are expected to occur in many future space operations. Due to a lack of buoyancy in the microgravity environment, two-phase flows are known to behave differently than those in earth gravity. Despite these concerns, little research has been conducted on microgravity two-phase flow and the current understanding is poor. This dissertation describes an experimental and modeling study of the characteristics of two-phase flows in microgravity. An experiment was operated onboard NASA aircraft capable of producing short periods of microgravity. In addition to high speed photographs of the flows, electronic measurements of void fraction, liquid film thickness, bubble and wave velocity, pressure drop and wall shear stress were made for a wide range of liquid and gas flow rates. The effects of liquid viscosity, surface tension and tube diameter on the behavior of these flows were also assessed. From the data collected, maps showing the occurrence of various flow patterns as a function of gas and liquid flow rates were constructed. Earth gravity two-phase flow models were compared to the results of the microgravity experiments and in some cases modified. Models were developed to predict the transitions on the flow pattern maps. Three flow patterns, bubble, slug and annular flow, were observed in microgravity. These patterns were found to occur in distinct regions of the gas-liquid flow rate parameter space. The effect of liquid viscosity, surface tension and tube diameter on the location of the boundaries of these regions was small. Void fraction and Weber number transition criteria both produced reasonable transition models. Void fraction and bubble velocity for bubble and slug flows were found to be well described by the Drift-Flux model used to describe such flows in earth gravity. Pressure drop modeling by the homogeneous flow model was inconclusive for bubble and slug flows. Annular flows were found to be complex systems of ring-like waves and a

  13. Casimir torque on a cylindrical gear

    NASA Astrophysics Data System (ADS)

    Vaidya, Varun

    2014-08-01

    I utilize effective field theory(EFT) techniques to calculate the Casimir torque on a cylindrical gear in the presence of a polarizable but neutral object and present results for the energy and torque as a function of angle for a gear with multiple cogs, as well as for the case of a concentric cylindrical gear.

  14. Impacts of tropical cyclones on Fiji and Samoa

    NASA Astrophysics Data System (ADS)

    Kuleshov, Yuriy; Prakash, Bipendra; Atalifo, Terry; Waqaicelua, Alipate; Seuseu, Sunny; Ausetalia Titimaea, Mulipola

    2013-04-01

    Weather and climate hazards have significant impacts on Pacific Island Countries. Costs of hazards such as tropical cyclones can be astronomical making enormous negative economic impacts on developing countries. We highlight examples of extreme weather events which have occurred in Fiji and Samoa in the last few decades and have caused major economic and social disruption in the countries. Destructive winds and torrential rain associated with tropical cyclones can bring the most damaging weather conditions to the region causing economic and social hardship, affecting agricultural productivity, infrastructure and economic development which can persist for many years after the initial impact. Analysing historical data, we describe the impacts of tropical cyclones Bebe and Kina on Fiji. Cyclone Bebe (October 1972) affected the whole Fiji especially the Yasawa Islands, Viti Levu and Kadavu where hurricane force winds have been recorded. Nineteen deaths were reported and damage costs caused by cyclone Bebe were estimated as exceeding F20 million (F 1972). Tropical cyclone Kina passed between Fiji's two main islands of Viti Levu and Vanua Levu, and directly over Levuka on the night of 2 January 1993 with hurricane force winds causing extensive damage. Twenty three deaths have been reported making Kina one of the deadliest hurricanes in Fiji's recent history. Severe flooding on Viti Levu, combined with high tide and heavy seas led to destruction of the Sigatoka and Ba bridges, as well as almost complete loss of crops in Sigatoka and Navua deltas. Overall, damage caused by cyclone Kina was estimated as F170 million. In Samoa, we describe devastation to the country caused by tropical cyclones Ofa (February 1990) and Val (December 1991) which were considered to be the worst cyclones to affect the Samoan islands since the 1889 Apia cyclone. In Samoa, seven people were killed due to cyclone Ofa, thousands of people were left homeless and entire villages were destroyed. Damage

  15. Noncircular orifice holes and advanced fabrication techniques for liquid rocket injectors. Phase 3: Analytical and cold-flow experimental evaluation of rectangular concentric tube injector elements for gas/liquid application. Phase 4: Analytical and experimental evaluation of noncircular injector elements for gas/liquid and liquid/liquid application

    NASA Technical Reports Server (NTRS)

    Mchale, R. M.

    1974-01-01

    Results are presented of a cold-flow and hot-fire experimental study of the mixing and atomization characteristics of injector elements incorporating noncircular orifices. Both liquid/liquid and gas/liquid element types are discussed. Unlike doublet and triplet elements (circular orifices only) were investigated for the liquid/liquid case while concentric tube elements were investigated for the gas/liquid case. It is concluded that noncircular shape can be employed to significant advantage in injector design for liquid rocket engines.

  16. Experimental investigation of the propagation of a planar shock wave through a two-phase gas-liquid medium

    NASA Astrophysics Data System (ADS)

    Chauvin, A.; Jourdan, G.; Daniel, E.; Houas, L.; Tosello, R.

    2011-11-01

    We conducted a series of shock tube experiments to study the influence of a cloud of water droplets on the propagation of a planar shock wave. In a vertically oriented shock tube, the cloud of droplets was released downwards into the air at atmospheric pressure while the shock wave propagated upwards. Two shock wave Mach numbers, 1.3 and 1.5, and three different heights of clouds, 150 mm, 400 mm, and 700 mm, were tested with an air-water volume fraction and a droplet diameter fixed at 1.2% and 500 μm, respectively. From high-speed visualization and pressure measurements, we analyzed the effect of water clouds on the propagation of the shock wave. It was shown that the pressure histories recorded in the two-phase gas-liquid mixture are different from those previously obtained in the gas-solid case. This different behavior is attributed to the process of atomization of the droplets, which is absent in the gas-solid medium. Finally, it was observed that the shock wave attenuation was dependent on the exchange surface crossed by the shock combined with the breakup criterion.

  17. The effect of microbubbles on gas-liquid mass transfer coefficient and degradation rate of COD in wastewater treatment.

    PubMed

    Yao, Kangning; Chi, Yong; Wang, Fei; Yan, Jianhua; Ni, Mingjiang; Cen, Kefa

    2016-01-01

    A commonly used aeration device at present has the disadvantages of low mass transfer rate because the generated bubbles are several millimeters in diameter which are much bigger than microbubbles. Therefore, the effect of a microbubble on gas-liquid mass transfer and wastewater treatment process was investigated. To evaluate the effect of each bubble type, the volumetric mass transfer coefficients for microbubbles and conventional bubbles were determined. The volumetric mass transfer coefficient was 0.02905 s(-1) and 0.02191 s(-1) at a gas flow rate of 0.67 L min(-1) in tap water for microbubbles and conventional bubbles, respectively. The degradation rate of simulated municipal wastewater was also investigated, using aerobic activated sludge and ozone. Compared with the conventional bubble generator, the chemical oxygen demand (COD) removal rate was 2.04, 5.9, 3.26 times higher than those of the conventional bubble contactor at the same initial COD concentration of COD 200 mg L(-1), 400 mg L(-1), and 600 mg L(-1), while aerobic activated sludge was used. For the ozonation process, the rate of COD removal using microbubble generator was 2.38, 2.51, 2.89 times of those of the conventional bubble generator. Based on the results, the effect of initial COD concentration on the specific COD degradation rate were discussed in different systems. Thus, the results revealed that microbubbles could enhance mass transfer in wastewater treatment and be an effective method to improve the degradation of wastewater.

  18. Correlations between the two-phase gas/liquid spray atomization and the Stokes/aerodynamic Weber numbers

    NASA Astrophysics Data System (ADS)

    Rahman, Mohammad A.; Heidrick, Ted; Fleck, Brian A.

    2009-02-01

    The The effects of air-to-liquid ratio (β) and void fraction (α) on Sauter mean diameter (SMD or D32), arithmetic mean diameter (D10), surface mean diameter (D20), volume mean diameter (VMD or D20), and radial velocity profiles were experimentally investigated for a two-phase gas/liquid (TPGL) nozzle with a hybrid design of classical twin-fluid and effervescent nozzles. Radial spray profiles were measured using a Phase-Doppler-Particle-Anemometer (PDPA) system on 15Dn, 30Dn, 60Dn, 120Dn;(Dn represents nozzle diameter = 3.10,mm) axial distances. In addition, the effects of spray break-up patterns were analyzed with changing axial distances. The average void fraction in the feeding conduit (FC) was measured by a pneumatic controlled quick-closing-valve (QCV). The experiments were performed using mixtures of air with water at water flow rates of 1.50 to 7.50 kg/min and air-to-liquid mass ratios (β) of 0.30 to 10;%. The length and diameter of the FC was 36.8,cm and 6.35,mm, respectively. Result indicates that as the St number reaches the value of one, no more break-up continues, thus the droplets start to coalesce each other forming bigger droplets (higher D10 values) with increasing radial distances. Knowledge from this study will provide better understanding that ensures an increase in plant efficiency and product yield in oil sands bitumen upgrading.

  19. Detection and quantification of cocoa butter equivalents in cocoa butter and plain chocolate by gas liquid chromatography of triacylglycerols.

    PubMed

    Buchgraber, Manuela; Senaldi, Chiara; Ulberth, Franz; Anklam, Elke

    2004-01-01

    The development and in-house testing of a method for the detection and quantification of cocoa butter equivalents in cocoa butter and plain chocolate is described. A database consisting of the triacylglycerol profile of 74 genuine cocoa butter and 75 cocoa butter equivalent samples obtained by high-resolution capillary gas liquid chromatography was created, using a certified cocoa butter reference material (IRMM-801) for calibration purposes. Based on these data, a large number of cocoa butter/cocoa butter equivalent mixtures were arithmetically simulated. By subjecting the data set to various statistical tools, reliable models for both detection (univariate regression model) and quantification (multivariate model) were elaborated. Validation data sets consisting of a large number of samples (n = 4050 for detection, n = 1050 for quantification) were used to test the models. Excluding pure illipé fat samples from the data set, the detection limit was determined between 1 and 3% foreign fat in cocoa butter. Recalculated for a chocolate with a fat content of 30%, these figures are equal to 0.3-0.9% cocoa butter equivalent. For quantification, the average error for prediction was estimated to be 1.1% cocoa butter equivalent in cocoa butter, without prior knowledge of the materials used in the blend corresponding to 0.3% in chocolate (fat content 30%). The advantage of the approach is that by using IRMM-801 for calibration, the established mathematical decision rules can be transferred to every testing laboratory.

  20. Evolution of flow disturbances in cocurrent gas-liquid flows. Progress report, November 1, 1992--October 31, 1992

    SciTech Connect

    McCready, M.J.

    1992-10-01

    Studies of interfacial waves in horizontal gas-liquid flows, close to neutral stability, suggest that the rate of evolution of the interface may be linked to nonlinear interactions between the fundamental mode and the subharmonic -- even if the subharmonic is linearly stable. The rate of evolution increases as the subharmonic becomes more unstable. A comparison of linear stability techniques used to predict the initial behavior of waves reveals similar predictions of growth rates and almost identical speeds between a two layer laminar Orr-Sommerfeld theory and an Orr-Sommerfeld theory when the effect of the (turbulent) gas flow enters as boundary conditions on the liquid layer. However, there is disagreement at small wavenumbers as to the point at which the growth curve crosses 0. This is a significant problem because longwave disturbances, in our case roll waves, form by growth of (initially) small amplitude waves that have frequencies which are 0.5 to 1 Hz, which is in the range where the two theories disagree about the sign of the growth rate. While nonlinear effects are probably involved in the formation of the peak (at least while its amplitude is small), the linear growth rate must play an important role when the amplitude is small.

  1. Microgravity Evaluation of Advantages of Porous Metal in the Gas-Liquid Equilibrium Thruster for Small Spacecraft

    NASA Astrophysics Data System (ADS)

    Motooka, Norizumi; Yamamoto, Takayuki; Mori, , Osamu; Kishino, Yoshihiro; Okano, Yoshinobu; Kawaguchi, Jun'Ichiro

    Microgravity experiments were performed to evaluate liquid propellant retention force of a porous metal. In our gas-liquid equilibrium propulsion system, porous metals are equipped in a storage tank and surface tension in pores of the porous metals holds liquid propellant in them, which ensures expelling of only gaseous propellant from a storage tank. The performance of a porous metal for liquid retention was evaluated by two different microgravity experiments. In the first one, the acrylic tank filled with semilunar porous metals and liquid propellant was rotated by a motor. The performance was evaluated by considering a force balance between liquid retention force and centrifugal force acting on the liquid propellant absorbed in porous metals. In the other one, the internal pressure in the tank was reduced by propellant ejection from a nozzle. The performance was evaluated by exhaustion time. As a result, it was found that liquid retention force was equal to, or higher than analytical value (bubble point pressure), and extractable gas volume of each ejection strongly depends on the existence of bubbles in liquid propellant.

  2. Comparison of two gas-liquid chromatograph columns for the analysis of fatty acids in ruminant meat.

    PubMed

    Alves, Susana P; Bessa, Rui J B

    2009-06-26

    Two gas-liquid chromatograph capillary columns for the analysis of fatty acids (FA) in ruminant fat are compared. Those columns are the CP-Sil 88 of 100 m long with a highly polar stationary phase and the Omegawax 250 of 30 m long with a stationary phase of intermediate polarity. Fatty acid methyl ester (FAME) patterns of branched-chain, cis and trans octadecenoate isomers, as well as conjugated and non-conjugated 18:2 and 18:3 isomers are fairly different between columns, even though most of the FAME could be separated on either column. However, the CP-Sil 88 showed better resolution of 18:1 isomers than Omegawax 250. The analysis of 96 samples of ruminant meat fat in both chromatographic systems showed that averages obtained for total FA content and for most of the individual FA did not differ between columns. Moreover, regression analysis of Omegawax and CP-Sil 88 data is highly correlated. Quantitative differences between chromatographic systems were detected for samples containing more than 66 mg fatty acids per gram of muscle dry matter.

  3. Controllable Synthesis of Formaldehyde Modified Manganese Oxide Based on Gas-Liquid Interfacial Reaction and Its Application of Electrochemical Sensing.

    PubMed

    Bai, Wushuang; Sheng, Qinglin; Nie, Fei; Zheng, Jianbin

    2015-12-30

    Controllable synthesis of manganese oxides was performed via a simple one-step synthetic method. Then obtained manganese oxides which exhibit flower-like, cloud-like, hexagon-like, and rod-like morphologies were modified by formaldehyde based on a simple self-made gas-liquid reaction device respectively and the modified manganese oxides with coral-like, scallop-like and rod-like morphology were synthesized accordingly. The obtained materials were characterized and the formation mechanism was also researched. Then the modified manganese oxides were used to fabricate electrochemical sensors to detect H2O2. Comparison of electrochemical properties between three kinds of modified manganese oxides was investigated and the best one has been successfully employed as H2O2 sensor which shows a low detection limit of 0.01 μM, high sensitivity of 162.69 μA mM(-1) cm(-2), and wide linear range of 0.05 μM-12.78 mM. The study provides a new method for controllable synthesis of metal oxides, and electrochemical application of formaldehyde modified manganese oxides will provides a new strategy for electrochemical sensing with high performance, low cost, and simple fabrication.

  4. Gas-liquid Two Phase Flow Modelling of Incompressible Fluid and Experimental Validation Studies in Vertical Centrifugal Casting

    NASA Astrophysics Data System (ADS)

    Zhou, J. X.; Shen, X.; Yin, Y. J.; Guo, Z.; Wang, H.

    2015-06-01

    In this paper, Gas-liquid two phase flow mathematic models of incompressible fluid were proposed to explore the feature of fluid under certain centrifugal force in vertical centrifugal casting (VCC). Modified projection-level-set method was introduced to solve the mathematic models. To validate the simulation results, two methods were used in this study. In the first method, the simulation result of basic VCC flow process was compared with its analytic solution. The relationship between the numerical solution and deterministic analytic solution was presented to verify the correctness of numerical algorithms. In the second method, systematic water simulation experiments were developed. In this initial experiment, special experimental vertical centrifugal device and casting shapes were designed to describe typical mold-filling processes in VCC. High speed camera system and data collection devices were used to capture flow shape during the mold-filling process. Moreover, fluid characteristic at different rotation speed (from 40rpm, 60rpmand 80rpm) was discussed to provide comparative resource for simulation results. As compared with the simulation results, the proposed mathematical models could be proven and the experimental design could help us advance the accuracy of simulation and further studies for VCC.

  5. Master singular behavior from correlation length measurements for seven one-component fluids near their gas-liquid critical point.

    PubMed

    Garrabos, Yves; Palencia, Fabien; Lecoutre, Carole; Erkey, Can; Le Neindre, Bernard

    2006-02-01

    We present the master (i.e., unique) behavior of the correlation length, as a function of the thermal field along the critical isochore, asymptotically close to the gas-liquid critical point of xenon, krypton, argon, helium-3, sulfur hexafluoride, carbon dioxide, and heavy water. It is remarkable that this unicity extends to the correction-to-scaling terms. The critical parameter set, which contains all the needed information to reveal the master behavior, is composed of four thermodynamic coordinates of the critical point and one adjustable parameter which accounts for quantum effects in the helium-3 case. We use a scale dilatation method applied to the relevant physical variables of the one-component fluid subclass, in analogy with the basic hypothesis of the renormalization theory. This master behavior for the correlation length satisfies hyperscaling. We finally estimate the thermal field extent where the critical crossover of the singular thermodynamic and correlation functions deviates from the theoretical crossover function obtained from field theory.

  6. Difficulties in applying laser technique to measure drop sizes in vertical and inclined Annular gas-liquid flows

    NASA Astrophysics Data System (ADS)

    Zaidi, Sohail H.

    1996-11-01

    Annular two phase flow is one of the most common regimes of gas/liquid flow found in industrial equipment. In this regime, the liquid flows in part as a film on the channel walls while the rest of the liquid is carried as drops by the gas flowing in the center of the channel. Detailed knowledge of the liquid drops particularly their sizes and velocities is essential in processes involving heat and mass transfer. This information is of great importance for the oil industry where inclined drilling has recently become a common practice. The effect of inclination on the drop sizes is still unknown and requires further investigation. Laser diffraction is one of the few available techniques which is widely used for the measurement of droplet size distribution. Although the technique is simple to use, it is not free from problems. This paper highlights the practical difficulties encountered when the technique was used to measure the drop size distribution in an inclinable flow column. The laser system was mounted on the rig and the flow column was rotated from vertical to horizontal position. Liquid drops appearing on the optical windows prohibited laser measurements. Other problems included the glass reflections and vibration when the rig was in operation. In this paper some practical suggestions have been made to overcome these problems and some useful results have been included.

  7. Visualization of gas-liquid mass transfer and wake structure of rising bubbles using pH-sensitive PLIF

    NASA Astrophysics Data System (ADS)

    Stöhr, M.; Schanze, J.; Khalili, A.

    2009-07-01

    A planar laser-induced fluorescence (PLIF) technique for visualizing gas-liquid mass transfer and wake structure of rising gas bubbles is described. The method uses an aqueous solution of the pH-sensitive dye Naphthofluorescein and CO2 as a tracer gas. It features a high spatial resolution and frame rates of up to 500 Hz, providing the ability to capture cinematographic image sequences. By steering the laser beam with a set of two programmable scanning mirrors, sequences of three-dimensional LIF images can be recorded. The technique is applied to freely rising bubbles with diameters between 0.5 and 5 mm, which perform rectilinear, oscillatory or irregular motions. The resulting PLIF image sequences reveal the evolution of characteristic patterns in the near and far wake of the bubbles and prove the potential of the technique to provide new and detailed insights into the spatio-temporal dynamics of mass transfer of rising gas bubbles. The image sequences further allow the estimation of bubble size and rise velocity. The analysis of bubble rise velocities in the Naphthofluorescein solution indicates that surfactant-contaminated conditions are encountered.

  8. Mass spectrometric identification and gas-liquid chromatographic determination of 2-chloroethyl esters of fatty acids in spices and foods.

    PubMed

    Heikes, D L; Griffitt, K R

    1979-07-01

    The 2-chloroethyl esters of 5 fatty acids have been identified in spice and food samples by gas-liquid chromatography-mass spectrometry (GLC/MS). Twenty-four spice samples were analyzed for the 2-chloroethyl esters of fatty acids by AOAC official multiple residues pesticide procedure using GLC with microcoulometric detection. The esters of capric, lauric, myristic, palmitic, and linoleic acids have been identified at levels up to 1400 ppm. 2-Chloroethyl linoleate was the most abundant ester in all samples. Several foods analyzed by the same procedures showed levels of 2-chloroethyl linoleate as high as 35 ppm. Recoveries from fortified samples ranged from 84 to 98% for the various esters. A method using an acid-catalyzed esterification reaction was developed to rapidly determine the fatty acid content of these spices. GLC analysis with microcoulometric detection was used. Recoveries from fortified samples ranged from 92 to 110%. After 2 spice samples found to be free of 2-chloroethyl esters were fumigated with ethylene oxide, the level of 2-chloroethyl linoleate reached 77 ppm. All levels of 2-chloroethyl esters were confirmed by GLC/MS.

  9. Ocean barrier layers' effect on tropical cyclone intensification.

    PubMed

    Balaguru, Karthik; Chang, Ping; Saravanan, R; Leung, L Ruby; Xu, Zhao; Li, Mingkui; Hsieh, Jen-Shan

    2012-09-04

    Improving a tropical cyclone's forecast and mitigating its destructive potential requires knowledge of various environmental factors that influence the cyclone's path and intensity. Herein, using a combination of observations and model simulations, we systematically demonstrate that tropical cyclone intensification is significantly affected by salinity-induced barrier layers, which are "quasi-permanent" features in the upper tropical oceans. When tropical cyclones pass over regions with barrier layers, the increased stratification and stability within the layer reduce storm-induced vertical mixing and sea surface temperature cooling. This causes an increase in enthalpy flux from the ocean to the atmosphere and, consequently, an intensification of tropical cyclones. On average, the tropical cyclone intensification rate is nearly 50% higher over regions with barrier layers, compared to regions without. Our finding, which underscores the importance of observing not only the upper-ocean thermal structure but also the salinity structure in deep tropical barrier layer regions, may be a key to more skillful predictions of tropical cyclone intensities through improved ocean state estimates and simulations of barrier layer processes. As the hydrological cycle responds to global warming, any associated changes in the barrier layer distribution must be considered in projecting future tropical cyclone activity.

  10. A Climatological Study of Hurricane Force Extratropical Cyclones

    DTIC Science & Technology

    2012-03-01

    8 d. Cloud Formation and Coherent Air Streams ............ 10 2. Explosive Deepening Cyclones “Bomb...eastern side of the surface low due the latent heat release (LHR) during condensation and cloud formation (Martin 2006). According to Martin 9...show that LHR served as an energy source that aids in the intensification of extratropical cyclones. 10 d. Cloud Formation and Coherent Air

  11. Novel cyclone empirical pressure drop and emissions with heterogeneous particulate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    New cyclone designs equally effective at controlling emissions that have smaller pressure losses would reduce both the financial and the environmental cost of procuring electricity. Tests were conducted with novel and industry standard 30.5 cm diameter cyclones at inlet velocities from 8 to 18 m s-...

  12. Could cyclone performance improve with reduced inlet velocity?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasingly stringent regulations have resulted in more restrictive air permit requirements at the same time that energy costs have risen. Cyclone operating strategies are sought so cotton gins can control particulate emissions using less energy with current cyclone technology. Tests were conducted...

  13. Ocean Barrier Layers’ Effect on Tropical Cyclone Intensification

    SciTech Connect

    Balaguru, Karthik; Chang, P.; Saravanan, R.; Leung, Lai-Yung R.; Xu, Zhao; Li, M.; Hsieh, J.

    2012-09-04

    Improving a tropical cyclone's forecast and mitigating its destructive potential requires knowledge of various environmental factors that influence the cyclone's path and intensity. Herein, using a combination of observations and model simulations, we systematically demonstrate that tropical cyclone intensification is significantly affected by salinity-induced barrier layers, which are 'quasi-permanent' features in the upper tropical oceans. When tropical cyclones pass over regions with barrier layers, the increased stratification and stability within the layer reduce storm-induced vertical mixing and sea surface temperature cooling. This causes an increase in enthalpy flux from the ocean to the atmosphere and, consequently, an intensification of tropical cyclones. On average, the tropical cyclone intensification rate is nearly 50% higher over regions with barrier layers, compared to regions without. Our finding, which underscores the importance of observing not only the upper-ocean thermal structure but also the salinity structure in deep tropical barrier layer regions, may be a key to more skillful predictions of tropical cyclone intensities through improved ocean state estimates and simulations of barrier layer processes. As the hydrological cycle responds to global warming, any associated changes in the barrier layer distribution must be considered in projecting future tropical cyclone activity.

  14. A new classification scheme of European cyclone tracks with relevance to precipitation

    NASA Astrophysics Data System (ADS)

    Hofstätter, M.; Chimani, B.; Lexer, A.; Blöschl, G.

    2016-09-01

    This paper proposes a new classification scheme of atmospheric cyclone tracks over Europe. The cyclones are classified into nine types, based on the geographic regions, the cyclones traverse before entering central Europe. The method is applied to ERA-40 data for 1961-2002, considering all significant cyclones above a relative vorticity threshold. About 120 and 80 cyclone tracks per year are identified at sea level pressure and 700 hPa geopotential height, respectively. About 25% are Atlantic type cyclones, 25% emerge directly over central Europe, and another 25% originate from the lee of the Alps. The other types are less frequent (Mediterranean 12%, Polar 7%, Continental 2%, and Vb 4%). The track types show distinct characteristics in terms of cyclone intensity and cyclone life stage when entering central Europe. Cyclones of type Vb are, on average, the most intense cyclones over central Europe and even more intense than Atlantic cyclones in summer, pointing to their potential for generating extreme precipitation. The identified cyclones account for 46%-76% of long-term precipitation in a focus region in central Europe. Precipitation differs significantly between cyclones, with Atlantic and Vb cyclones producing the highest and Continental and Polar cyclones producing the lowest long-term precipitation totals. The contributions of cyclone types to total precipitation show distinct spatial patterns within central Europe. The new cyclone type catalog will be useful for identifying the relevance of specific track types for precipitation extremes in central Europe and analyze their temporal behavior in the context of climate change.

  15. Lessons learnt from tropical cyclone losses

    NASA Astrophysics Data System (ADS)

    Honegger, Caspar; Wüest, Marc; Zimmerli, Peter; Schoeck, Konrad

    2016-04-01

    Swiss Re has a long history in developing natural catastrophe loss models. The tropical cyclone USA and China model are examples for event-based models in their second generation. Both are based on basin-wide probabilistic track sets and calculate explicitly the losses from the sub-perils wind and storm surge in an insurance portfolio. Based on these models, we present two cases studies. China: a view on recent typhoon loss history Over the last 20 years only very few major tropical cyclones have caused severe insurance losses in the Pearl River Delta region and Shanghai, the two main exposure clusters along China's southeast coast. Several storms have made landfall in China every year but most struck areas with relatively low insured values. With this study, we make the point that typhoon landfalls in China have a strong hit-or-miss character and available insured loss experience is too short to form a representative view of risk. Historical storm tracks and a simple loss model applied to a market portfolio - all from publicly available data - are sufficient to illustrate this. An event-based probabilistic model is necessary for a reliable judgement of the typhoon risk in China. New York: current and future tropical cyclone risk In the aftermath of hurricane Sandy 2012, Swiss Re supported the City of New York in identifying ways to significantly improve the resilience to severe weather and climate change. Swiss Re provided a quantitative assessment of potential climate related risks facing the city as well as measures that could reduce those impacts.

  16. Tropical Cyclone Monty Strikes Western Australia

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The Multi-angle Imaging SpectroRadiometer (MISR) acquired these natural color images and cloud top height measurements for Monty before and after the storm made landfall over the remote Pilbara region of Western Australia, on February 29 and March 2, 2004 (shown as the left and right-hand image sets, respectively). On February 29, Monty was upgraded to category 4 cyclone status. After traveling inland about 300 kilometers to the south, the cyclonic circulation had decayed considerably, although category 3 force winds were reported on the ground. Some parts of the drought-affected Pilbara region received more than 300 millimeters of rainfall, and serious and extensive flooding has occurred.

    The natural color images cover much of the same area, although the right-hand panels are offset slightly to the east. Automated stereoscopic processing of data from multiple MISR cameras was utilized to produce the cloud-top height fields. The distinctive spatial patterns of the clouds provide the necessary contrast to enable automated feature matching between images acquired at different view angles. The height retrievals are at this stage uncorrected for the effects of the high winds associated with cyclone rotation. Areas where heights could not be retrieved are shown in dark gray.

    The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days views the entire globe between 82 degrees north and 82 degrees south latitude. These data products were generated from a portion of the imagery acquired during Terra orbits 22335 and 22364. The panels cover an area of about 380 kilometers x 985 kilometers, and utilize data from blocks 105 to 111 within World Reference System-2 paths 115 and 113.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the

  17. A Classification of Mediterranean Cyclones Based on Global Analyses

    NASA Technical Reports Server (NTRS)

    Reale, Oreste; Atlas, Robert

    2003-01-01

    The Mediterranean Sea region is dominated by baroclinic and orographic cyclogenesis. However, previous work has demonstrated the existence of rare but intense subsynoptic-scale cyclones displaying remarkable similarities to tropical cyclones and polar lows, including, but not limited to, an eye-like feature in the satellite imagery. The terms polar low and tropical cyclone have been often used interchangeably when referring to small-scale, convective Mediterranean vortices and no definitive statement has been made so far on their nature, be it sub-tropical or polar. Moreover, most of the classifications of Mediterranean cyclones have neglected the small-scale convective vortices, focusing only on the larger-scale and far more common baroclinic cyclones. A classification of all Mediterranean cyclones based on operational global analyses is proposed The classification is based on normalized horizontal shear, vertical shear, scale, low versus mid-level vorticity, low-level temperature gradients, and sea surface temperatures. In the classification system there is a continuum of possible events, according to the increasing role of barotropic instability and decreasing role of baroclinic instability. One of the main results is that the Mediterranean tropical cyclone-like vortices and the Mediterranean polar lows appear to be different types of events, in spite of the apparent similarity of their satellite imagery. A consistent terminology is adopted, stating that tropical cyclone- like vortices are the less baroclinic of all, followed by polar lows, cold small-scale cyclones and finally baroclinic lee cyclones. This classification is based on all the cyclones which occurred in a four-year period (between 1996 and 1999). Four cyclones, selected among all the ones which developed during this time-frame, are analyzed. Particularly, the classification allows to discriminate between two cyclones (occurred in October 1996 and in March 1999) which both display a very well

  18. Tropical cyclone intensity change. A quantitative forecasting scheme

    NASA Technical Reports Server (NTRS)

    Dropco, K. M.; Gray, W. M.

    1981-01-01

    One to two day future tropical cyclone intensity change from both a composite and an individual case point-of-view are discussed. Tropical cyclones occurring in the Gulf of Mexico during the period 1957-1977 form the primary data source. Weather charts of the NW Atlantic were initially examined, but few differences were found between intensifying and non-intensifying cyclones. A rawinsonde composite analysis detected composite differences in the 200 mb height fields, the 850 mb temperature fields, the 200 mb zonal wind and the vertical shears of the zonal wind. The individual cyclones which make up the composite study were then separately examined using this composite case knowledge. Similar parameter differences were found in a majority of individual cases. A cyclone intensity change forecast scheme was tested against independent storm cases. Correct predictions of intensification or non-intensification could be made approximately 75% of the time.

  19. Extreme Arctic cyclones in CMIP5 historical simulations

    NASA Astrophysics Data System (ADS)

    Vavrus, Stephen J.

    2013-12-01

    attention is being paid to extreme weather, including recent high-profile events involving very destructive cyclones. In summer 2012, a historically powerful cyclone traversed the Arctic, a region experiencing rapid warming and dramatic loss of ice and snow cover. This study addresses whether such powerful storms are an emerging expression of anthropogenic climate change by investigating simulated extreme Arctic cyclones during the historical period (1850-2005) among global climate models in the Coupled Model Intercomparison Project 5 (CMIP5) archive. These general circulation models are able to simulate extreme pressures associated with strong polar storms without a significant dependence on model resolution. The models display realism by generating extreme Arctic storms primarily around subpolar cyclone regions (Aleutian and Icelandic) and preferentially during winter. Simulated secular trends in Arctic mean sea level pressure and extreme cyclones are equivocal; both indicate increasing storminess in some regions, but the magnitude of changes to date are modest compared with future projections.

  20. Sensitivity of tropical cyclone intensity to sea surface temperature

    SciTech Connect

    Evans, J.L. )

    1993-06-01

    Increased occurrence of more intense tropical storms intruding further poleward has been foreshadowed as one of the potential consequences of global warming. This scenario is based almost entirely on the general circulation model predictions of warmer sea surface temperature (SST) with increasing levels of atmospheric CO[sub 2] and some theories of tropical cyclone intensification that support the notion of more intense systems with warmer SST. Whether storms are able to achieve this theoretically determined more intense state depends on whether the temperature of the underlying water is the dominant factor in tropical cyclone intensification. An examination of the historical data record in a number of ocean basins is used to identify the relative importance of SST in the tropical cyclone intensification process. The results reveal that SST alone is an inadequate predictor of tropical cyclone intensity. Other factors known to affect tropical cyclone frequency and intensity are discussed. 16 refs., 6 figs., 3 tabs.

  1. Supplementing Oscat winds with Saral Altika observations for cyclone studies

    NASA Astrophysics Data System (ADS)

    Niharika, K.; Usha Sundari, H. S. V.; Prasad, A. V. V.; Kumari, E. V. S. Sita; Dadhwal, V. K.; Ali, M. M.

    2014-11-01

    Accurate prediction of life cycle of cyclone is very critical to the disaster management practices. Since the cyclones originate over the oceans where in situ observations are limited, we have to resort to the remote sensing techniques. Both optical and microwave sensors help studying the cyclones. While scatterometer provide wind vectors, altimeters can give only wind speed. In this paper we present how altimeter measurements can supplement the scatterometer observations in determining the radius of maximum winds (RMW). Sustained maximum winds, indicator for the intensity of the cyclone, are within the eye wall of a cyclone at a distance of RMW. This parameter is also useful in predicting right time of the storm surge. In this paper we used the wind speed estimations from AltiKa, an altimeter operating at Ka band.

  2. Modelling flow pattern transitions for steady upward gas-liquid flow in vertical tubes. [Bubble, slug, churn and dispersed-annular; also existence regions and transitions

    SciTech Connect

    Taitel, Y.; Bornea, D.; Dukler, A.E.

    1980-05-01

    Models for predicting flow patterns in steady upward gas-liquid flow in vertical tubes (such as production-well tubing) delineate the transition boundaries between each of the four basic flow patterns for gas-liquid flow in vertical tubes: bubble, slug, churn, and dispersed-annular. Model results suggest that churn flow is the development region for the slug pattern and that bubble flow can exist in small pipes only at high liquid rates, where turbulent dispersion forces are high. Each transition depends on the flow-rate pair, fluid properties, and pipe size, but the nature of the dependence is different for each transition because of differing control mechanisms. The theoretical predictions are in reasonably good agreement with a variety of published flow maps based on experimental data.

  3. Stratified coastal ocean interactions with tropical cyclones

    PubMed Central

    Glenn, S. M.; Miles, T. N.; Seroka, G. N.; Xu, Y.; Forney, R. K.; Yu, F.; Roarty, H.; Schofield, O.; Kohut, J.

    2016-01-01

    Hurricane-intensity forecast improvements currently lag the progress achieved for hurricane tracks. Integrated ocean observations and simulations during hurricane Irene (2011) reveal that the wind-forced two-layer circulation of the stratified coastal ocean, and resultant shear-induced mixing, led to significant and rapid ahead-of-eye-centre cooling (at least 6 °C and up to 11 °C) over a wide swath of the continental shelf. Atmospheric simulations establish this cooling as the missing contribution required to reproduce Irene's accelerated intensity reduction. Historical buoys from 1985 to 2015 show that ahead-of-eye-centre cooling occurred beneath all 11 tropical cyclones that traversed the Mid-Atlantic Bight continental shelf during stratified summer conditions. A Yellow Sea buoy similarly revealed significant and rapid ahead-of-eye-centre cooling during Typhoon Muifa (2011). These findings establish that including realistic coastal baroclinic processes in forecasts of storm intensity and impacts will be increasingly critical to mid-latitude population centres as sea levels rise and tropical cyclone maximum intensities migrate poleward. PMID:26953963

  4. Stratified coastal ocean interactions with tropical cyclones

    NASA Astrophysics Data System (ADS)

    Glenn, S. M.; Miles, T. N.; Seroka, G. N.; Xu, Y.; Forney, R. K.; Yu, F.; Roarty, H.; Schofield, O.; Kohut, J.

    2016-03-01

    Hurricane-intensity forecast improvements currently lag the progress achieved for hurricane tracks. Integrated ocean observations and simulations during hurricane Irene (2011) reveal that the wind-forced two-layer circulation of the stratified coastal ocean, and resultant shear-induced mixing, led to significant and rapid ahead-of-eye-centre cooling (at least 6 °C and up to 11 °C) over a wide swath of the continental shelf. Atmospheric simulations establish this cooling as the missing contribution required to reproduce Irene's accelerated intensity reduction. Historical buoys from 1985 to 2015 show that ahead-of-eye-centre cooling occurred beneath all 11 tropical cyclones that traversed the Mid-Atlantic Bight continental shelf during stratified summer conditions. A Yellow Sea buoy similarly revealed significant and rapid ahead-of-eye-centre cooling during Typhoon Muifa (2011). These findings establish that including realistic coastal baroclinic processes in forecasts of storm intensity and impacts will be increasingly critical to mid-latitude population centres as sea levels rise and tropical cyclone maximum intensities migrate poleward.

  5. Thin cylindrical sheets of air

    NASA Astrophysics Data System (ADS)

    Thoroddsen, Sigurdur; Beilharz, Daniel; Guyon, Axel; Li, Er Qiang; Thoraval, Marie-Jean

    2014-11-01

    Drops impacting at low velocities onto a pool surface can stretch out thin hemispheric sheets of air. These air sheets can remain intact until they reach submicron thicknesses, whereby they rupture to form myriad of microbubbles. By impacting a higher-viscosity drop onto a lower-viscosity pool, we have explored new geometries of such air films. In this way we are able to maintain stable air-layers which can wrap around the entire drop to form anti-bubbles, i.e. spherical air layers bounded by inner and outer liquid masses. Furthermore, for the most viscous drops they enter the pool trailing a viscous thread from the pinch-off from the nozzle. The air sheet can also wrap around these treads and remain stable over extended time to form a cylindrical air sheet. We study the parameter regime where these structures appear and their subsequent breakup. The stability of these air cylinders is inconsistent with inviscid stability theory, suggesting stabilization by lubrication forces within the submicron air layer.

  6. Radially sandwiched cylindrical piezoelectric transducer

    NASA Astrophysics Data System (ADS)

    Lin, Shuyu; Fu, Zhiqiang; Zhang, Xiaoli; Wang, Yong; Hu, Jing

    2013-01-01

    A new type of radially sandwiched piezoelectric short cylindrical transducer is developed and its radial vibration is studied. The transducer is composed of a solid metal disk, a radially polarized piezoelectric ceramic short tube and a metal tube. The radial vibrations of the solid metal disk, the radially polarized piezoelectric tube and the metal tube are analyzed and their electromechanical equivalent circuits are introduced. Based on the mechanical boundary conditions among the metal disk, the piezoelectric tube and the metal tube, a three-port electromechanical equivalent circuit for the radially sandwiched transducer is obtained and the frequency equation is given. The theoretical relationship of the resonance and anti-resonance frequencies and the effective electromechanical coupling coefficient with the geometrical dimensions is analyzed. The radial vibration of the sandwiched transducer is simulated by using two different numerical methods. It is shown that the analytical resonance and anti-resonance frequencies are in good agreement with the numerically simulated results. The transducer is expected to be used in piezoelectric resonators, actuators and ultrasonic radiators in ultrasonic and underwater sound applications.

  7. The study of flow characteristic of gas-liquid two-phase flow based on the near-infrared detection device

    NASA Astrophysics Data System (ADS)

    Fang, Lide; Liang, Yujiao; Zhang, Yao; Zhang, Chen; Gao, Jingzhe

    2014-04-01

    With the importance of the two-phase flow, many scholars pay attention on it; and for the so many parameters in the gas-liquid two-phase flow, flow characteristic is the basis. For the four flow patterns in the vertical direction, slug flow, bubbly flow, annular flow, and milk foam-like flow, the paper used the laser diode of 980nm and the silicon photodiode to detect the flow status. The absorption coefficients of the infrared in the gas and the liquid are very different; at the meantime, the infrared is affected by the interface obviously. As a result, it can reflect the fluctuation of the gas-liquid two-phase flow with the detection by the infrared. By analyzing the experiment data, four characteristic parameters are extracted, such as the average value, the variance, the kurtosis, and the frequency center of gravity. They can not only reflect the change of the different flow patterns, but also can reflect the fluctuation in the same flow pattern. The feature vector constituted of the four characteristic parameters can identify the flow pattern correctly in this system. What's more, it can achieve an accurate measurement of the real-time online, providing a basis for the other parameters' analysis in the gas-liquid two-phase flow.

  8. Low Cost Chemical Feedstocks Using an Improved and Energy Efficient Natural Gas Liquid (NGL) Removal Process, Final Technical Report

    SciTech Connect

    Meyer, Howard, S.; Lu, Yingzhong

    2012-08-10

    The overall objective of this project is to develop a new low-cost and energy efficient Natural Gas Liquid (NGL) recovery process - through a combination of theoretical, bench-scale and pilot-scale testing - so that it could be offered to the natural gas industry for commercialization. The new process, known as the IROA process, is based on U.S. patent No. 6,553,784, which if commercialized, has the potential of achieving substantial energy savings compared to currently used cryogenic technology. When successfully developed, this technology will benefit the petrochemical industry, which uses NGL as feedstocks, and will also benefit other chemical industries that utilize gas-liquid separation and distillation under similar operating conditions. Specific goals and objectives of the overall program include: (i) collecting relevant physical property and Vapor Liquid Equilibrium (VLE) data for the design and evaluation of the new technology, (ii) solving critical R&D issues including the identification of suitable dehydration and NGL absorbing solvents, inhibiting corrosion, and specifying proper packing structure and materials, (iii) designing, construction and operation of bench and pilot-scale units to verify design performance, (iv) computer simulation of the process using commercial software simulation platforms such as Aspen-Plus and HYSYS, and (v) preparation of a commercialization plan and identification of industrial partners that are interested in utilizing the new technology. NGL is a collective term for C2+ hydrocarbons present in the natural gas. Historically, the commercial value of the separated NGL components has been greater than the thermal value of these liquids in the gas. The revenue derived from extracting NGLs is crucial to ensuring the overall profitability of the domestic natural gas production industry and therefore of ensuring a secure and reliable supply in the 48 contiguous states. However, rising natural gas prices have dramatically reduced

  9. Banded tremor: its cyclic nature and source mechanism inferred from gas-liquid two-phase flow instability

    NASA Astrophysics Data System (ADS)

    Fujita, E.

    2011-12-01

    Seismic and geodetic network around volcano often detects curios rhythmic phenomena. In this paper, we will focus on banded tremor occurring in the hydrothermal system at shallow depths beneath volcanoes. Banded tremor consists of series of "tremor packets" occurring in some intervals. Tremor packets have same characteristics with ordinal volcanic tremor often observed at many volcanoes, and are sometimes monotonic and/or harmonic. The durations and intervals of these tremor packets are almost constant during the one session of activity. For example, in case of banded tremor at Miyakejima volcano, Japan, the durations and intervals are about ten minutes and 25 - 40 minutes, respectively during the 2001 to 2006. These cyclic characteristics can be interpreted by the instability of gas-liquid two-phase flow. When a shallow water plumbing system is heated by magma underneath and vaporization occur, and the relation between total flux and pressure loss show N-shape characteristics, which cause instabilities due to negative resistance. This mechanism is formulated by the equations of two-phase flow, and we obtained the analytical eigen equation. It turns out that this system has two specific oscillating modes, i.e., damping oscillation and excursion mode. The damping oscillation mode corresponds to each tremor packet, and is due to the instability of two-phase flow called "density-wave oscillation." The numerical simulation of density-wave oscillation gives the details of its nature like temporal and spatial distributions of void fractions, density and velocities in the pipe system. The excursion mode is non-linear oscillation and corresponds to cycles of banded tremor. The condition for the existence of an excursion mode is defined by the relation between subcool enthalpy and total heat flux. Based on these models, banded tremor is realized in the order of heat flux of 1-10 MW.

  10. Critical point of gas-liquid type phase transition and phase equilibrium functions in developed two-component plasma model

    SciTech Connect

    Butlitsky, M. A.; Zelener, B. V.

    2014-07-14

    A two-component plasma model, which we called a “shelf Coulomb” model has been developed in this work. A Monte Carlo study has been undertaken to calculate equations of state, pair distribution functions, internal energies, and other thermodynamics properties. A canonical NVT ensemble with periodic boundary conditions was used. The motivation behind the model is also discussed in this work. The “shelf Coulomb” model can be compared to classical two-component (electron-proton) model where charges with zero size interact via a classical Coulomb law. With important difference for interaction of opposite charges: electrons and protons interact via the Coulomb law for large distances between particles, while interaction potential is cut off on small distances. The cut off distance is defined by an arbitrary ε parameter, which depends on system temperature. All the thermodynamics properties of the model depend on dimensionless parameters ε and γ = βe{sup 2}n{sup 1/3} (where β = 1/k{sub B}T, n is the particle's density, k{sub B} is the Boltzmann constant, and T is the temperature) only. In addition, it has been shown that the virial theorem works in this model. All the calculations were carried over a wide range of dimensionless ε and γ parameters in order to find the phase transition region, critical point, spinodal, and binodal lines of a model system. The system is observed to undergo a first order gas-liquid type phase transition with the critical point being in the vicinity of ε{sub crit}≈13(T{sub crit}{sup *}≈0.076),γ{sub crit}≈1.8(v{sub crit}{sup *}≈0.17),P{sub crit}{sup *}≈0.39, where specific volume v* = 1/γ{sup 3} and reduced temperature T{sup *} = ε{sup −1}.

  11. [Research on diagnosis of gas-liquid detonation exhaust based on double optical path absortion spectroscopy technique].

    PubMed

    Lü, Xiao-Jing; Li, Ning; Weng, Chun-Sheng

    2014-03-01

    The effect detection of detonation exhaust can provide measurement data for exploring the formation mechanism of detonation, the promotion of detonation efficiency and the reduction of fuel waste. Based on tunable diode laser absorption spectroscopy technique combined with double optical path cross-correlation algorithm, the article raises the diagnosis method to realize the on-line testing of detonation exhaust velocity, temperature and H2O gas concentration. The double optical path testing system is designed and set up for the valveless pulse detonation engine with the diameter of 80 mm. By scanning H2O absorption lines of 1343nm with a high frequency of 50 kHz, the on-line detection of gas-liquid pulse detonation exhaust is realized. The results show that the optical testing system based on tunable diode laser absorption spectroscopy technique can capture the detailed characteristics of pulse detonation exhaust in the transient process of detonation. The duration of single detonation is 85 ms under laboratory conditions, among which supersonic injection time is 5.7 ms and subsonic injection time is 19.3 ms. The valveless pulse detonation engine used can work under frequency of 11 Hz. The velocity of detonation overflowing the detonation tube is 1,172 m x s(-1), the maximum temperature of detonation exhaust near the nozzle is 2 412 K. There is a transitory platform in the velocity curve as well as the temperature curve. H2O gas concentration changes between 0-7% during detonation under experimental conditions. The research can provide measurement data for the detonation process diagnosis and analysis, which is of significance to advance the detonation mechanism research and promote the research of pulse detonation engine control technology.

  12. Measurements of liquid-phase turbulence in gas-liquid two-phase flows using particle image velocimetry

    NASA Astrophysics Data System (ADS)

    Zhou, Xinquan; Doup, Benjamin; Sun, Xiaodong

    2013-12-01

    Liquid-phase turbulence measurements were performed in an air-water two-phase flow loop with a circular test section of 50 mm inner diameter using a particle image velocimetry (PIV) system. An optical phase separation method--planar laser-induced fluorescence (PLIF) technique—which uses fluorescent particles and an optical filtration technique, was employed to separate the signals of the fluorescent seeding particles from those due to bubbles and other noises. An image pre-processing scheme was applied to the raw PIV images to remove the noise residuals that are not removed by the PLIF technique. In addition, four-sensor conductivity probes were adopted to measure the radial distribution of the void fraction. Two benchmark tests were performed: the first was a comparison of the PIV measurement results with those of similar flow conditions using thermal anemometry from previous studies; the second quantitatively compared the superficial liquid velocities calculated from the local liquid velocity and void fraction measurements with the global liquid flow rate measurements. The differences of the superficial liquid velocity obtained from the two measurements were bounded within ±7% for single-phase flows and two-phase bubbly flows with the area-average void fraction up to 18%. Furthermore, a preliminary uncertainty analysis was conducted to investigate the accuracy of the two-phase PIV measurements. The systematic uncertainties due to the circular pipe curvature effects, bubble surface reflection effects and other potential uncertainty sources of the PIV measurements were discussed. The purpose of this work is to facilitate the development of a measurement technique (PIV-PLIF) combined with image pre-processing for the liquid-phase turbulence in gas-liquid two-phase flows of relatively high void fractions. The high-resolution data set can be used to more thoroughly understand two-phase flow behavior, develop liquid-phase turbulence models, and assess high

  13. Quantum State-Resolved Reactive and Inelastic Scattering at Gas-Liquid and Gas-Solid Interfaces

    NASA Astrophysics Data System (ADS)

    Grütter, Monika; Nelson, Daniel J.; Nesbitt, David J.

    2012-06-01

    Quantum state-resolved reactive and inelastic scattering at gas-liquid and gas-solid interfaces has become a research field of considerable interest in recent years. The collision and reaction dynamics of internally cold gas beams from liquid or solid surfaces is governed by two main processes, impulsive scattering (IS), where the incident particles scatter in a few-collisions environment from the surface, and trapping-desorption (TD), where full equilibration to the surface temperature (T{TD}≈ T{s}) occurs prior to the particles' return to the gas phase. Impulsive scattering events, on the other hand, result in significant rotational, and to a lesser extent vibrational, excitation of the scattered molecules, which can be well-described by a Boltzmann-distribution at a temperature (T{IS}>>T{s}). The quantum-state resolved detection used here allows the disentanglement of the rotational, vibrational, and translational degrees of freedom of the scattered molecules. The two examples discussed are (i) reactive scattering of monoatomic fluorine from room-temperature ionic liquids (RTILs) and (ii) inelastic scattering of benzene from a heated (˜500 K) gold surface. In the former experiment, rovibrational states of the nascent HF beam are detected using direct infrared absorption spectroscopy, and in the latter, a resonace-enhanced multi-photon-ionization (REMPI) scheme is employed in combination with a velocity-map imaging (VMI) device, which allows the detection of different vibrational states of benzene excited during the scattering process. M. E. Saecker, S. T. Govoni, D. V. Kowalski, M. E. King and G. M. Nathanson Science 252, 1421, 1991. A. M. Zolot, W. W. Harper, B. G. Perkins, P. J. Dagdigian and D. J. Nesbitt J. Chem. Phys 125, 021101, 2006. J. R. Roscioli and D. J. Nesbitt Faraday Disc. 150, 471, 2011.

  14. Development of a gas-liquid chromatographic method for the analysis of fatty acid tryptamides in cocoa products.

    PubMed

    Hug, Bernadette; Golay, Pierre-Alain; Giuffrida, Francesca; Dionisi, Fabiola; Destaillats, Frédéric

    2006-05-03

    The determination of the occurrence and level of cocoa shells in cocoa products and chocolate is an important analytical issue. The recent European Union directive on cocoa and chocolate products (2000/36/EC) has not retained the former limit of a maximum amount of 5% of cocoa shells in cocoa nibs (based on fat-free dry matter), previously authorized for the elaboration of cocoa products such as cocoa mass. In the present study, we report a reliable gas-liquid chromatography procedure suitable for the determination of the occurrence of cocoa shells in cocoa products by detection of fatty acid tryptamides (FATs). The precision of the method was evaluated by analyzing nine different samples (cocoa liquors with different ranges of shells) six times (replicate repeatability). The variations of the robust coefficient of variation of the repeatability demonstrated that FAT(C22), FAT(C24), and total FATs are good markers for the detection of shells in cocoa products. The trueness of the method was evaluated by determining the FAT content in two spiked matrices (cocoa liquors and cocoa shells) at different levels (from 1 to 50 mg/100 g). A good relation was found between the results obtained and the spiking (recovery varied between 90 and 130%), and the linearity range was established between 1 and 50 mg/100 g in cocoa products. For total FAT contents of cocoa liquor containing 5% shells, the measurement uncertainty allows us to conclude that FAT is equal to 4.01 +/- 0.8 mg/100 g. This validated method is perfectly suitable to determine shell contents in cocoa products using FAT(C22), FAT(C24), and total FATs as markers. The results also confirmed that cocoa shells contain FAT(C24) and FAT(C22) in a constant ratio of nearly 2:1.

  15. Temporal clustering of tropical cyclones and its ecosystem impacts.

    PubMed

    Mumby, Peter J; Vitolo, Renato; Stephenson, David B

    2011-10-25

    Tropical cyclones have massive economic, social, and ecological impacts, and models of their occurrence influence many planning activities from setting insurance premiums to conservation planning. Most impact models allow for geographically varying cyclone rates but assume that individual storm events occur randomly with constant rate in time. This study analyzes the statistical properties of Atlantic tropical cyclones and shows that local cyclone counts vary in time, with periods of elevated activity followed by relative quiescence. Such temporal clustering is particularly strong in the Caribbean Sea, along the coasts of Belize, Honduras, Costa Rica, Jamaica, the southwest of Haiti, and in the main hurricane development region in the North Atlantic between Africa and the Caribbean. Failing to recognize this natural nonstationarity in cyclone rates can give inaccurate impact predictions. We demonstrate this by exploring cyclone impacts on coral reefs. For a given cyclone rate, we find that clustered events have a less detrimental impact than independent random events. Predictions using a standard random hurricane model were overly pessimistic, predicting reef degradation more than a decade earlier than that expected under clustered disturbance. The presence of clustering allows coral reefs more time to recover to healthier states, but the impacts of clustering will vary from one ecosystem to another.

  16. Scaling parameters for PFBC cyclone separator system analysis

    SciTech Connect

    Gil, A.; Romeo, L.M.; Cortes, C.

    1999-07-01

    Laboratory-scale cold flow models have been used extensively to study the behavior of many installations. In particular, fluidized bed cold flow models have allowed developing the knowledge of fluidized bed hydrodynamics. In order for the results of the research to be relevant to commercial power plants, cold flow models must be properly scaled. Many efforts have been made to understand the performance of fluidized beds, but up to now no attention has been paid in developing the knowledge of cyclone separator systems. CIRCE has worked on the development of scaling parameters to enable laboratory-scale equipment operating at room temperature to simulate the performance of cyclone separator systems. This paper presents the simplified scaling parameters and experimental comparison of a cyclone separator system and a cold flow model constructed and based on those parameters. The cold flow model has been used to establish the validity of the scaling laws for cyclone separator systems and permits detailed room temperature studies (determining the filtration effects of varying operating parameters and cyclone design) to be performed in a rapid and cost effective manner. This valuable and reliable design tool will contribute to a more rapid and concise understanding of hot gas filtration systems based on cyclones. The study of the behavior of the cold flow model, including observation and measurements of flow patterns in cyclones and diplegs will allow characterizing the performance of the full-scale ash removal system, establishing safe limits of operation and testing design improvements.

  17. Damaging sediment density flows triggered by tropical cyclones

    NASA Astrophysics Data System (ADS)

    Pope, Ed L.; Talling, Peter J.; Carter, Lionel; Clare, Michael A.; Hunt, James E.

    2017-01-01

    The global network of subsea fibre-optic cables plays a critical role in the world economy and is considered as strategic infrastructure for many nations. Sediment density flows have caused significant disruption to this network in the recent past. These cable breaks represent the only means to actively monitor such flows over large oceanic regions. Here, we use a global cable break database to analyse tropical cyclone triggering of sediment density flows worldwide over 25 yrs. Cable breaking sediment density flows are triggered in nearly all areas exposed to tropical cyclones but most occur in the NW Pacific. They are triggered by one of three sets of mechanisms. Tropical cyclones directly trigger flows, synchronous to their passage, as a consequence of storm waves, currents and surges. Cyclones also trigger flows indirectly, with near-synchronous timing to their passage, as a consequence of peak flood discharges. Last, cyclones trigger flows after a delay of days as a consequence of the failure of large volumes of rapidly deposited sediment. No clear relationship emerges between tropical cyclone activity (i.e. track, frequency and intensity) and the number of sediment density flows triggered. This is a consequence of the short period of observation. However, expansion of the cable network and predicted changes to cyclone activity in specific regions increases the likelihood of increasing numbers of damaging flows.

  18. The increasing intensity of the strongest tropical cyclones.

    PubMed

    Elsner, James B; Kossin, James P; Jagger, Thomas H

    2008-09-04

    Atlantic tropical cyclones are getting stronger on average, with a 30-year trend that has been related to an increase in ocean temperatures over the Atlantic Ocean and elsewhere. Over the rest of the tropics, however, possible trends in tropical cyclone intensity are less obvious, owing to the unreliability and incompleteness of the observational record and to a restricted focus, in previous trend analyses, on changes in average intensity. Here we overcome these two limitations by examining trends in the upper quantiles of per-cyclone maximum wind speeds (that is, the maximum intensities that cyclones achieve during their lifetimes), estimated from homogeneous data derived from an archive of satellite records. We find significant upward trends for wind speed quantiles above the 70th percentile, with trends as high as 0.3 +/- 0.09 m s(-1) yr(-1) (s.e.) for the strongest cyclones. We note separate upward trends in the estimated lifetime-maximum wind speeds of the very strongest tropical cyclones (99th percentile) over each ocean basin, with the largest increase at this quantile occurring over the North Atlantic, although not all basins show statistically significant increases. Our results are qualitatively consistent with the hypothesis that as the seas warm, the ocean has more energy to convert to tropical cyclone wind.

  19. Temporal clustering of tropical cyclones and its ecosystem impacts

    PubMed Central

    Mumby, Peter J.; Vitolo, Renato; Stephenson, David B.

    2011-01-01

    Tropical cyclones have massive economic, social, and ecological impacts, and models of their occurrence influence many planning activities from setting insurance premiums to conservation planning. Most impact models allow for geographically varying cyclone rates but assume that individual storm events occur randomly with constant rate in time. This study analyzes the statistical properties of Atlantic tropical cyclones and shows that local cyclone counts vary in time, with periods of elevated activity followed by relative quiescence. Such temporal clustering is particularly strong in the Caribbean Sea, along the coasts of Belize, Honduras, Costa Rica, Jamaica, the southwest of Haiti, and in the main hurricane development region in the North Atlantic between Africa and the Caribbean. Failing to recognize this natural nonstationarity in cyclone rates can give inaccurate impact predictions. We demonstrate this by exploring cyclone impacts on coral reefs. For a given cyclone rate, we find that clustered events have a less detrimental impact than independent random events. Predictions using a standard random hurricane model were overly pessimistic, predicting reef degradation more than a decade earlier than that expected under clustered disturbance. The presence of clustering allows coral reefs more time to recover to healthier states, but the impacts of clustering will vary from one ecosystem to another. PMID:22006300

  20. Tropical Cyclone Signatures in Atmospheric Convective Available Potential Energy

    NASA Astrophysics Data System (ADS)

    Studholme, Joshua; Gulev, Sergey

    2016-04-01

    Tropical cyclones play an important role in the climate system providing transports of energy and water vapor, forcing the ocean, and also affecting mid-latitude circulation phenomena. Tropical cyclone tracks experience strong interannual variability and in addition, longer term trend-like changes in all ocean basins. Analysis of recent historical data reveal a poleward shift in the locations of tropical cyclone tracks in both the Northern and Southern Hemispheres (Kossin et al. 2014, Nature, 509, 349-352). The physical consequences of these alterations are largely unconstrained. For example, the increasing encroachment of tropical cyclone activity into the extra-tropical environment presents a novel and still poorly understood paradigm for tropical-extratropical interactions. In this respect, the role that the atmospheric convective available potential energy (CAPE) plays in the dynamics of tropical cyclones is highly interesting. The two characteristic global-scale spatial patterns in CAPE are identified using EOF analysis. The first pattern shows an abundance of CAPE in the centre of the Pacific and corresponds to the El Nino Southern Oscillation. The second one is capturing positive CAPE anomalies in the oceanic tropics and negative anomalies over equatorial Africa. Associated with these buoyancy patterns, alterations in tropical cyclone activity occur in all basins forming both zonal and meridional patterns. Atmospheric buoyancy is the trigger for deep convection, and subsequently cyclone genesis. This is the mechanism of impact upon location at the start of cyclone tracks. It is found to have less impact upon where cyclones subsequently move, whether or not they undergo extratropical transition and when and where they experience lysis. It is shown that CAPE plays a critical role in the general circulation in the tropics which in turn is the larger steering context for embedded systems within the Walker and Hadley cells. So this lack of `latter life' impact

  1. Multiple Satellite Observations of Cloud Cover in Extratropical Cyclones

    NASA Technical Reports Server (NTRS)

    Naud, Catherine M.; Booth, James F.; Posselt, Derek J.; van den Heever, Susan C.

    2013-01-01

    Using cloud observations from NASA Moderate Resolution Imaging Spectroradiometer, Multiangle Imaging Spectroradiometer, and CloudSat-CALIPSO, composites of cloud fraction in southern and northern hemisphere extratropical cyclones are obtained for cold and warm seasons between 2006 and 2010, to assess differences between these three data sets, and between summer and winter cyclones. In both hemispheres and seasons, over the open ocean, the cyclone-centered cloud fraction composites agree within 5% across the three data sets, but behind the cold fronts, or over sea ice and land, the differences are much larger. To supplement the data set comparison and learn more about the cyclones, we also examine the differences in cloud fraction between cold and warm season for each data set. The difference in cloud fraction between cold and warm season southern hemisphere cyclones is small for all three data sets, but of the same order of magnitude as the differences between the data sets. The cold-warm season contrast in northern hemisphere cyclone cloud fractions is similar for all three data sets: in the warm sector, the cold season cloud fractions are lower close to the low, but larger on the equator edge than their warm season counterparts. This seasonal contrast in cloud fraction within the cyclones warm sector seems to be related to the seasonal differences in moisture flux within the cyclones. Our analysis suggests that the three different data sets can all be used confidently when studying the warm sector and warm frontal zone of extratropical cyclones but caution should be exerted when studying clouds in the cold sector.

  2. Extra-tropical Cyclones and Windstorms in Seasonal Forecasts

    NASA Astrophysics Data System (ADS)

    Leckebusch, Gregor C.; Befort, Daniel J.; Weisheimer, Antje; Knight, Jeff; Thornton, Hazel; Roberts, Julia; Hermanson, Leon

    2015-04-01

    Severe damages and large insured losses over Europe related to natural phenomena are mostly caused by extra-tropical cyclones and their related windstorm fields. Thus, an adequate representation of these events in seasonal prediction systems and reliable forecasts up to a season in advance would be of high value for society and economy. In this study, state-of-the-art seasonal forecast prediction systems are analysed (ECMWF, UK Met Office) regarding the general climatological representation and the seasonal prediction of extra-tropical cyclones and windstorms during the core winter season (DJF) with a lead time of up to four months. Two different algorithms are used to identify cyclones and windstorm events in these datasets. Firstly, we apply a cyclone identification and tracking algorithm based on the Laplacian of MSLP and secondly, we use an objective wind field tracking algorithm to identify and track continuous areas of extreme high wind speeds (cf. Leckebusch et al., 2008), which can be related to extra-tropical winter cyclones. Thus, for the first time, we can analyse the forecast of severe wind events near to the surface caused by extra-tropical cyclones. First results suggest a successful validation of the spatial climatological distributions of wind storm and cyclone occurrence in the seasonal forecast systems in comparison with reanalysis data (ECMWF-ERA40 & ERAInterim) in general. However, large biases are found for some areas. The skill of the seasonal forecast systems in simulating the year-to-year variability of the frequency of severe windstorm events and cyclones is investigated using the ranked probability skill score. Positive skill is found over large parts of the Northern Hemisphere as well as for the most intense extra-tropical cyclones and its related wind fields.

  3. Sea ice trends and cyclone activity in the Southern Ocean

    NASA Astrophysics Data System (ADS)

    Coggins, Jack; McDonald, Adrian; Rack, Wolfgang; Dale, Ethan

    2015-04-01

    Significant trends in the extent of Southern Hemisphere sea ice have been noted over the course of the satellite record, with highly variable trends between different seasons and regions. In this presentation, we describe efforts to assess the impact of cyclones on these trends. Employing a maximum cross-correlation method, we derive Southern Ocean ice-motion vectors from daily gridded SSMI 85.5 GHz brightness temperatures. We then derive a sea ice budget from the NASA-Team 25 km square daily sea ice concentrations. The budget quantifies the total daily change in sea ice area, and includes terms representing the effects of ice advection and divergence. A residual term represents the processes of rafting, ridging, freezing and thawing. We employ a cyclone tracking algorithm developed at the University of Canterbury to determine the timing, location, size and strength of Southern Hemisphere cyclones from mean sea-level pressure fields of the ERA-Interim reanalysis. We then form composites of the of sea ice budget below the location of cyclones. Unsurprisingly, we find that clockwise atmospheric flow around Southern Hemisphere cyclones exerts a strong influence on the movement of sea ice, an effect which is visible in the advection and divergence terms. Further, we assess the climatological importance of cyclones by comparing seasons of sea ice advance for periods with varying numbers of cyclones. This analysis is performed independently for each sea ice concentration pixel, thus affording us insight into the geographical importance of storm systems. We find that Southern Hemisphere sea ice extent is highly sensitive to the presence of cyclones in the periphery of the pack in the advance season. Notably, the sensitivity is particularly high in the northern Ross Sea, an area with a marked positive trend in sea ice extent. We discuss whether trends in cyclone activity in the Southern Ocean may have contributed to sea ice extent trends in this region.

  4. Crack problems in cylindrical and spherical shells

    NASA Technical Reports Server (NTRS)

    Erdogan, F.

    1976-01-01

    Standard plate or shell theories were used as a starting point to study the fracture problems in thin-walled cylindrical and spherical shells, assuming that the plane of the crack is perpendicular to the surface of the sheet. Since recent studies have shown that local shell curvatures may have a rather considerable effect on the stress intensity factor, the crack problem was considered in conjunction with a shell rather than a plate theory. The material was assumed to be isotropic and homogeneous, so that approximate solutions may be obtained by approximating the local shell crack geometry with an ideal shell which has a solution, namely a spherical shell with a meridional crack, a cylindrical shell with a circumferential crack, or a cylindrical shell with an axial crack. A method of solution for the specially orthotropic shells containing a crack was described; symmetric and skew-symmetric problems are considered in cylindrical shells with an axial crack.

  5. Damage experiments in cylindrical geometry update

    SciTech Connect

    Kaul, Anne; Holtkamp, David; Rodriguez, George

    2009-01-01

    Using a cylindrical configuration to study spallation damage allows for a natural recollection of the damaged material under proper driving conditions. Previous experiments provided data about failure initiation in aluminum in a cylindrical geometry and the behavior of material recollected after damage from pressures in the damage initiation regime. The current series of experiments studied the behavior of material recollected after complete failure. Results from the current experiments will be presented.

  6. Object recognition using cylindrical harmonic filter.

    PubMed

    Guerrero Bermúdez, Jáder

    2004-06-28

    We present the cylindrical harmonic filter for three-dimensional (3D) discrete correlation between range data. The filter guarantees invariance of the correlation peak intensity under target rotation around z-axis. It can be considered a harmonic decomposition, in cylindrical coordinates, of the 3D Fourier spectrum of the target. Some simulation results confirm the in-plane rotation invariance and the discrimination of the filter.

  7. View factors of cylindrical spiral surfaces

    NASA Astrophysics Data System (ADS)

    Lebedev, Vladimir A.; Solovjov, Vladimir P.

    2016-03-01

    Analytical expressions are presented for the view factors (radiative configuration factors) associated with the flat right cylindrical spiral surface. Such cylindrical spiral systems are widely applied as electrical resistance heating elements for lighting devices, electronic radio tubes, high-speed gas flow heaters, and other appliances used for scientific, industrial and domestic purposes. Derivation of the view factors is based on the invariant principles and the results presented in Lebedev (2000, 2003,1988) [1-3].

  8. Cylindrical Antenna Using Near Zero Index Metamaterial

    DTIC Science & Technology

    2012-07-24

    device for enhancing the directivity and port isolation of a dual-frequency dual- polarization (DFDP) microstrip antenna by using metamaterial... Directivity Microstrip Patch Antenna Based on Zero-Index Metamaterial," IEEE Antennas and Wireless Prop. Letters, vol.8, no., pp.538-541, 2009. [0008...Invention [0003] The present invention is generally directed towards a cylindrical antenna and more specifically directed towards a cylindrical

  9. Spontaneous transition from flat to cylindrical solitons

    SciTech Connect

    Frycz, P.; Infeld, E. )

    1989-07-24

    Flat, cylindrical, and spherical soliton solutions to various model equations are known. Many of these exact solutions have been seen in numerical simulations. However, there are few simulations that actually show that exact flat solitons can break up into an array of exact cylindrical or spherical solitons and follow this on a step by step basis. This Letter presents the first of these two kinds of transition for the Zakharov-Kuznetsov equation governing ion acoustic solitons in strongly magnetized plasmas.

  10. Compact cyclone filter train for radiological and hazardous environments

    DOEpatents

    Bench, Thomas R.

    1998-01-01

    A compact cyclone filter train for the removal of hazardous and radiologi particles from a gaseous fluid medium which permits a small cyclone separator to be used in a very small space envelope due to the arrangement of the filter housing adjacent to the separator with the cyclone separator and the filters mounted on a plate. The entire unit will have a hoist connection at the center of gravity so that the entire unit including the separator, the filters, and the base can be lifted and repositioned as desired.

  11. Plasma-cyclone technology for firing solid fuels

    NASA Astrophysics Data System (ADS)

    Karpenko, Yu. E.; Messerle, V. E.; Karpenko, E. I.; Basargin, A. P.

    2014-08-01

    A new coal combustion technology is described, which involves preparation of fuel for combustion by subjecting it to electrothermochemical treatment followed by vortex firing of pulverized-coal fuel in a cyclone chamber with removing the molten mineral part of the fuel. A procedure for stepped calculation of the plasma-cyclone process is presented, which includes stage-wise determination of gas flow state parameters, mineral part of fuel, and geometrical characteristics of the chamber. The results of experimental investigations confirming the main theoretical statements are given. The solid fuel plasma-cyclone combustion technology application field including power-generating and power-processing areas is defined.

  12. Coastal flooding by tropical cyclones and sea-level rise.

    PubMed

    Woodruff, Jonathan D; Irish, Jennifer L; Camargo, Suzana J

    2013-12-05

    The future impacts of climate change on landfalling tropical cyclones are unclear. Regardless of this uncertainty, flooding by tropical cyclones will increase as a result of accelerated sea-level rise. Under similar rates of rapid sea-level rise during the early Holocene epoch most low-lying sedimentary coastlines were generally much less resilient to storm impacts. Society must learn to live with a rapidly evolving shoreline that is increasingly prone to flooding from tropical cyclones. These impacts can be mitigated partly with adaptive strategies, which include careful stewardship of sediments and reductions in human-induced land subsidence.

  13. Compact cyclone filter train for radiological and hazardous environments

    DOEpatents

    Bench, T.R.

    1998-04-28

    A compact cyclone filter train is disclosed for the removal of hazardous and radiological particles from a gaseous fluid medium. This filter train permits a small cyclone separator to be used in a very small space envelope due to the arrangement of the filter housing adjacent to the separator with the cyclone separator and the filters mounted on a plate. The entire unit will have a hoist connection at the center of gravity so that the entire unit including the separator, the filters, and the base can be lifted and repositioned as desired. 3 figs.

  14. Cyclone: A close air support aircraft for tomorrow

    NASA Technical Reports Server (NTRS)

    Cox, George; Croulet, Donald; Dunn, James; Graham, Michael; Ip, Phillip; Low, Scott; Vance, Gregg; Volckaert, Eric

    1991-01-01

    To meet the threat of the battlefield of the future, the U.S. ground forces will require reliable air support. To provide this support, future aircrews demand a versatile close air support aircraft capable of delivering ordinance during the day, night, or in adverse weather with pin-point accuracy. The Cyclone aircraft meets these requirements, packing the 'punch' necessary to clear the way for effective ground operations. Possessing anti-armor, missile, and precision bombing capability, the Cyclone will counter the threat into the 21st Century. Here, it is shown that the Cyclone is a realistic, economical answer to the demand for a capable close air support aircraft.

  15. Compact cyclone filter train for radiological and hazardous environments

    SciTech Connect

    Bench, T.R.

    1996-12-31

    A compact cyclone filter train is described for the removal of hazardous and radiological particles from a gaseous fluid medium which permits a small cyclone separator to be used in a very small space envelope due to the arrangement of the filter housing adjacent to the separator with the cyclone separators and the filters mounted on a plate. The entire unit will have a hoist connection at the center of gravity so that the entire unit including the separator, the filters, and the base can be lifted and repositioned as desired.

  16. Projecting global tropical cyclone economic damages with validation of tropical cyclone economic damage model

    NASA Astrophysics Data System (ADS)

    Iseri, Y.; Iwasaki, A.; Miyazaki, C.; Kanae, S.

    2014-12-01

    Tropical cyclones (TCs) sometimes cause serious damages to human society and thus possible changes of TC properties in the future have been concerned. In fact, the Fifth Assessment Report (AR5) by IPCC (Intergovernmental Panel on Climate Change) mentions likely increasing in intensity and rain rate of TCs. In addition, future change of socioeconomic condition (e.g. population growth) might worsen TC impacts in the future. Thereby, in this study, we developed regression models to estimate economic damages by TCs (hereafter TC damage model), and employed those models to project TC economic damages under several future climate and socioeconomic scenarios. We developed the TC damage models for each of 4 regions; western North Pacific, North American, North Indian, and Southern Hemisphere. The inputs for TC damage model are tropical cyclone central pressure, populations in the area exposed by tropical cyclone wind, and GDP (Gross Domestic Product) per capita. The TC damage models we firstly developed tended to overestimate very low damages and also underestimate very high damages. Thereby we modified structure of TC damage models to improve model performance, and then executed extensive validation of the model. The modified model presented better performance in estimating very low and high TC damages. After the modification and validation of the model, we determined the structure of TC damage models and projected TC economic damages. The result indicated increase in TC economic damage in global scale, while TC economic damage against world GDP would decrease in the future, which result is consistent with previous study.

  17. Simulating flow and segregation of cylindrical particles

    NASA Astrophysics Data System (ADS)

    Zhao, Yongzhi; Umbanhowar, Paul B.; Lueptow, Richard M.

    2015-11-01

    Efficient and accurate simulation of cylindrical particles using discrete element method (DEM) is a challenge. Typical approaches to simulating cylindrical particle systems are based on the glued spheres method, which has low accuracy, or real shape models, which have high computational cost. In this work we utilize super-ellipsoids, which belong to super-quadrics, to model cylindrical particles in DEM simulations. Simulations of a single cylinder impacting a flat wall indicate that super-ellipsoids provide the same accuracy as real shape models and much better accuracy than the glued sphere method. Simulations of super-ellipsoid cylindrical particles in rotating tumblers result in nearly the same angle of repose as experiments and real shape simulations, demonstrating the accuracy of super-ellipsoid DEM simulations for multi-particle systems. The segregation of bidisperse cylindrical particles differing in length in a bounded heap was simulated by super-ellipsoid DEM, and the results are similar to the experiment. In spite of these advantages of using super-ellipsoid cylindrical particles, simulations of filling a box with particles indicate that the simulation times for super-ellipsoid cylinders is about an order of magnitude longer than that for the same number of spherical particles.

  18. An analysis of consensus and disagreement among different cyclone tracking methods on the climatology of cyclones in the Mediterranean region

    NASA Astrophysics Data System (ADS)

    Lionello, Piero; Trigo, Isabel F.; Gil, Victoria; Liberato, Margarida M. L.; Nissen, Katrin M.; Pinto, Joaquim G.; Raible, Christof C.; Reale, Marco; Tanzarella, Annalisa; Trigo, Ricardo M.; Ulbrich, Sven; Ulbrich, Uwe

    2016-04-01

    Small but intense features and frequent cyclogenesis characterize the Mediterranean storm track (a well-defined branch of the North Hemisphere storm track) and pose a challenge for cyclone detection and tracking methods. Because of this, the analysis of the climatology of cyclones in the Mediterranean region is an ideal case study for investigating consensus and disagreement among methods. To identify robust features and sources of disagreement is important for giving the correct weight to the results of several studies that considered trends and future change of cyclone number and intensity in the Mediterranean region. In this study a set of 14 cyclone detection and tracking methods has been used and applied to the ERA-Interim dataset for the period 1979-2008. Results show large differences in actual cyclone numbers among different methods, but a substantial consensus on location, annual cycle and trends of cyclone tracks. In general, methods agree on cyclogenesis areas, such as the north-western Mediterranean, North Africa, north shore of the Levantine basin, as well as the seasonality of their maxima. Disagreement among methods is largest when counting weak and slow cyclones. It is substantially reduced if cyclone numbers are transformed to a dimensionless index, which helps to focus on sign and significance of trends by separating information on time behaviours and spatial structures from the differences of mean values and interannual variances. Results show significant negative trends in spring and positive trends in summer, which compensate each other at annual scale, so that there is no significant long-term trend in total cyclone numbers in the Mediterranean basin in the 1979-2008 period.

  19. Tropical cyclone recurvature: An intrinsic property?

    NASA Astrophysics Data System (ADS)

    Chan, Kelvin T. F.; Chan, Johnny C. L.

    2016-08-01

    The typical track of a tropical cyclone (TC) in the Northern Hemisphere is an initial northwestward movement followed by an eventual turning toward the east. Such turning is referred to as recurvature and often explained by the change of the environmental flow that steers the TC. Here we show that even in the absence of background flow, a TC initiated at a high enough latitude can recurve itself. Differential horizontal advection of the planetary vorticity by the TC circulation at different vertical levels leads to the development of vertical wind shear, upper tropospheric anticyclone, and asymmetric distribution of convection. The flow associated with the upper tropospheric anticyclone on the equatorward side of the TC and the diabatic heating associated with the asymmetric convection combine to cause the TC to recurve. Such knowledge, an intrinsic recurvature property of the TC is important in forecasting the TC track when the environmental flow is weak.

  20. Tropical cyclone intensities from satellite microwave data

    NASA Technical Reports Server (NTRS)

    Vonderhaar, T. H.; Kidder, S. Q.

    1980-01-01

    Radial profiles of mean 1000 mb to 250 mb temperature from the Nimbus 6 scanning microwave spectrometer (SCAMS) were constructed around eight intensifying tropical storms in the western Pacific. Seven storms showed distinct inward temperature gradients required for intensification; the eighth displayed no inward gradient and was decaying 24 hours later. The possibility that satellite data might be used to forecast tropical cyclone turning motion was investigated using estimates obtained from Nimbus 6 SCAMS data tapes of the mean 1000 mb to 250 mb temperature field around eleven tropical storms in 1975. Analysis of these data show that for turning storms, in all but one case, the turn was signaled 24 hours in advance by a significant temperature gradient perpendicular to the storm's path, at a distance of 9 deg to 13 deg in front of the storm. A thresholding technique was applied to the North Central U.S. during the summer to estimate precipitation frequency. except

  1. NASA Sees Heavy Rain in Arabian Sea Tropical Cyclone

    NASA Video Gallery

    On June 29, GPM showed Tropical Cyclone 02A had a few powerful convective thunderstorms southwest of the center of circulation were dropping rain at the extreme rate of over 209 mm (8.2 inches) per...

  2. Trends in Northern Hemisphere surface cyclone frequency and intensity

    USGS Publications Warehouse

    McCabe, G.J.; Clark, M.P.; Serreze, M.C.

    2001-01-01

    One of the hypothesized effects of global warming from increasing concentrations of greenhouse gases is a change in the frequency and/or intensity of extratropical cyclones. In this study, winter frequencies and intensities of extratropical cyclones in the Northern Hemisphere for the period 1959-97 are examined to determine if identifiable trends are occurring. Results indicate a statistically significant decrease in midlatitude cyclone frequency and a significant increase in high-latitude cyclone frequency. In addition, storm intensity has increased in both the high and midlatitudes. The changes in storm frequency correlate with changes in winter Northern Hemisphere temperature and support hypotheses that global warming may result in a northward shift of storm tracks in the Northern Hemisphere.

  3. Rainfall Totals from the Tropical Cyclones Passing Over Philippines

    NASA Video Gallery

    Rainfall totals from the TRMM satellite of all tropical cyclones that passed through the Philippines from January through November 11, 2013. Red indicated areas where rainfall totals were greater t...

  4. Coal reburning for cyclone boiler NO sub x control demonstration

    SciTech Connect

    Not Available

    1991-01-01

    It is the objective of the Coal Reburning for Cyclone Boiler NO{sub x} Control Project to fully establish that the cola reburning clean coal technology offers cost-effective alternatives to cyclone operating electric utilities for overall oxides of nitrogen control. The project will evaluate the applicability of the reburning technology for reducing NO{sub x} emissions in full scale cyclone-fired boilers which use coal as a primary fuel. The performance goals while burning coal are: (1) Greater than 50 percent reduction in NO{sub x} emissions, as referenced to the uncontrolled (baseline) conditions at full load. (2) No serious impact on cyclone combustor operation, boiler efficiency or boiler fireside performance (corrosion and deposition), or boiler ash removal system performance.

  5. TRMM Sees Rainfall Totals from Tropical Cyclone Guito

    NASA Video Gallery

    This animation of rainfall gathered from February 11-19, 2014 by NASA's TRMM satellite revealed that Tropical Cyclone Guito produced as much as 16.9 inches/430 mm of rainfall in the center of the M...

  6. Tropical Cyclone Mahasen Rain Moving Into Bay Of Bengal

    NASA Video Gallery

    This animated TRMM Multisatellite Precipitation Analysis shows the rainfall that occurred with Tropical Cyclone Mahasen during the week of May 6 through 13, 2013 as it moved through the Bay of Beng...

  7. NASA Sees Heavy Rainfall, Hot Towers in Tropical Cyclone Nathan

    NASA Video Gallery

    NASA-JAXA's Tropical Rainfall Measuring Mission or TRMM satellite showed that the heaviest rainfall occurring in Tropical Cyclone Nathan on March 18 at 0758 UTC (3:58 a.m. EDT) was falling at a rat...

  8. GPM Satellite Flyby of Tropical Cyclone 03S

    NASA Video Gallery

    On January 25 at 6:51 p.m. EST (2351 UTC) the GPM satellite found rainfall rates in some of the bands of thunderstorms around the developing tropical cyclone were falling at a rate of almost 83 mm ...

  9. GPM Sees Heavy Rain in Tropical Cyclone Yvette

    NASA Video Gallery

    On Dec. 19, the GPM core satellite found Tropical Cyclone 02S was dropping rain at a rate of over 127 mm (5 inches) per hour in this area of intense convective showers where cloud tops reached alti...

  10. Tropical cyclone motion and recurvature in TCM-90. Master's thesis

    SciTech Connect

    Fitzpatrick, M.E.

    1992-01-01

    Rawinsonde and satellite data collected during the Tropical Cyclone Motion (TCM90) experiment, which was conducted during the summer of 1990 in the Western North pacific, is used to examine tropical cyclone steering motion and recurvature. TCM-90 composite results are compared with those found in a composite study using twenty-one years (1957-77) of Western North Pacific rawinsonde data during the same August-September period and also for all months during this same 21-year period. Both data sets indicate that the composite deep-layer-mean (850-300 mb) winds 5-7 deg from the cyclone center provide an important component of the steering flow for tropical cyclones. However, despite the rawinsonde data enhancements of the TCM-90 experiment, data limitations prevented an accurate observation of steering flow conditions at individual time periods or for the average of only 5-10 time periods when composited together.

  11. GPM Satellite Sees Heavy Rainfall in Tropical Cyclone Carlos

    NASA Video Gallery

    The GPM core observatory satellite flew above tropical cyclone Carlos on February 7, 2017 at 1056 UTC and measured a few downpours in the bands west of the Carlos' center of circulation dropping ra...

  12. Application of ``water only`` cyclone in Slovak steam coal preparation

    SciTech Connect

    Jakabsky, S.; Lovas, M.; Hredzak, S.

    1998-12-31

    The paper deals with the possibilities of water only cyclone application in steam coal preparation with the aim to decrease the ash content in coal and to increase the coal heating value. The steam coal of the three Slovak coal localities from the Upper Nitra Basin was subjected to separation in a hydrocyclone without using a heavy medium. The influence of pressure and solid particle concentration is described. The steam coal preparation scheme proposal including the water only cyclones is also introduced.

  13. Simulation of Extreme Arctic Cyclones in IPCC AR5 Experiments

    DTIC Science & Technology

    2012-09-30

    of the current generation of global climate models (GCMs) to simulate extreme Arctic cyclones and identify changes in the characteristics of these...2011). 5. The CCSM4 simulations show an interesting shift in the location of extreme Arctic cyclones as a function of greenhouse warming (Figure 1...preferred track over the North Atlantic-Barents Sea. However, this change is not effected by the modest greenhouse warming between 1850-2000, when

  14. Simulation of Extreme Arctic Cyclones in IPCC AR5 Experiments

    DTIC Science & Technology

    2014-05-15

    cyclones and identify changes in the characteristics of these storms caused by greenhouse -forced climate change to present. OBJECTIVES These goals...How well do state-of-the-art GCMs simulate them? (3) Are extreme Arctic cyclones already showing a response to greenhouse forcing? APPROACH These...study used 14 GCMs with widely varying horizontal and vertical resolutions and physics packages. These simulations were compared with an atmospheric

  15. Two phase granular transport in cylindrical confinement

    NASA Astrophysics Data System (ADS)

    Ayaz, Monem; Toussaint, Renaud; Måløy, Knut-Jørgen

    2016-04-01

    We experimentally study the granular transport properties of a gas/liquid interface as it progresses trough a horizontal capillary tube, filled with a mixture of water and a sedimented granular layer.The displacement dynamics of such dense mixtures exhibit a rheology determined by the frictional interactions between the individual grains, capillary thresholds and the viscous interactions. By direct imaging and pressure measurements we observe different transport regimes as the pumping rate is varied. We classify these regimes according to the observed predominance of frictional or viscous interactions in a phase diagram. For the frictional regime the granular material is not transported out of the tube but structured in a pattern, characterized by its series of granular plugs and gaps. with the pressure signal displaying intermittent stick-slip behavior.

  16. Extratropical cyclone classification and its use in climate studies

    NASA Astrophysics Data System (ADS)

    Catto, J. L.

    2016-06-01

    Extratropical cyclones have long been known to be important for midlatitude weather. It is therefore important that our current state-of-the-art climate models are able to realistically represent these features, in order that we can have confidence in how they are projected to change in a warming climate. Despite the observation that these cyclones are extremely variable in their structure and features, there have, over the years, been numerous attempts to classify or group them. Such classifications can provide insight into the different cloud structures, airflows, and dynamical forcing mechanisms within the different cyclone types. This review collects and details as many classification techniques as possible, and may therefore act as a reference guide to classifications. These classifications offer the opportunity to improve the way extratropical cyclone evaluation in climate models is currently done by giving more insight into the dynamical and physical processes that occur in climate models (rather than just evaluating the mean state over a broad region as is often done). Examples of where these ideas have been used, or could be used, are reviewed. Finally, the potential impacts of future climate changes on extratropical cyclones are detailed. The ways in which the classification techniques could improve our understanding of future changes in extratropical cyclones and their impacts are given.

  17. Tropical cyclone activity over the Southwest Tropical Indian Ocean

    NASA Astrophysics Data System (ADS)

    Burns, Jessica M.; Subrahmanyam, Bulusu; Nyadjro, Ebenezer S.; Murty, V. S. N.

    2016-08-01

    The Southwest Tropical Indian Ocean (SWTIO) is a key region for air-sea interaction. Tropical cyclones (TCs) regularly form over the SWTIO and subsurface ocean variability influences the cyclogenesis of this region. Tropical cyclone days for this region span from November through April, and peak in January and February during austral summer. Past research provides evidence for more tropical cyclone days over the SWTIO during austral summer (December-June) with a deep thermocline ridge than in austral summer with a shallow thermocline ridge. We have analyzed the Argo temperature data and HYbrid Coordinate Ocean Model (HYCOM) outputs while focusing on the austral summer of 2012/2013 (a positive Indian Ocean Dipole (IOD) year and neutral El Niño Southern Oscillation (ENSO) year) when seven named tropical cyclones developed over the SWTIO region. This study reveals that the climatic events like the IOD and ENSO influence the cyclonic activity and number of TC days over the SWTIO. We ascertain that the IOD events have linkages with the Barrier Layer Thickness (BLT) in the SWTIO region through propagating Rossby waves, and further show that the BLT variability influences the cyclonic activity in this region.

  18. Close interactions between the Antarctic cyclone budget and large-scale atmospheric circulation

    NASA Astrophysics Data System (ADS)

    Uotila, Petteri; Vihma, Timo; Tsukernik, Maria

    2013-06-01

    the first time, we quantify relationships between the Southern Ocean cyclones and large-scale atmospheric variability indices: the Southern Annular Mode (SAM), the El Niño-Southern Oscillation (ENSO), the Zonal Wave 3 (ZW3) pattern, and the semiannual oscillation (SAO). Using the ERA-Interim 1979-2011 results, we identify cyclones south of 40°S and calculate monthly sectoral cyclone budgets of the Southern Ocean, defined as cyclogenesis minus cyclolysis plus net movement of cyclones into each sector. The SAM index has a strong connection with cyclones across all sectors. Positive SAM values are related to decreased eastward and increased southward movement of cyclones, resulting in higher cyclone densities along the Antarctic coast. The ENSO index shows strong associations with the cyclone behavior in the Amundsen-Ross Seas, whereas other regions are less sensitive to it. The ZW3 index has a stronger association with the meridional movement of cyclones than other indices.

  19. Theoretical and experimental investigation of converging cylindrical shock waves propagating in narrow cylindrical chambers

    NASA Astrophysics Data System (ADS)

    Zitouni, Gley

    1992-09-01

    The propagation and stability of converging cylindrical shocks produced in an annular shock tube equipped with a three increment area contraction were investigated for various cylindrical chamber widths and two annular shock Mach numbers of 1.26 and 1.44. The method of characteristics, integrated using the Hartree scheme, was employed to determine the shock Mach number and pressure-time variations in the cylindrical chamber. These numerical values were verified experimentally by employing a set of piezoelectric pressure transducers placed at five different locations. In narrow cylindrical chambers, a new test section was used to determine the boundary layer effect on the shock strength. For a cylindrical chamber width of 2.5 mm, experimental results were found to be in excellent agreement with the inviscid numerical solution. For smaller widths, an empirical equation of the shock Mach number variation was developed. Stability of the converging shocks was examined from the series of spark shadowgraphs taken near the geometric center.

  20. The Dizzying Depths of the Cylindrical Mirror

    NASA Astrophysics Data System (ADS)

    DeWeerd, Alan J.; Hill, S. Eric

    2005-02-01

    A typical introduction to geometrical optics treats plane and spherical mirrors. At first glance, it may be surprising that texts seldom mention the cylindrical mirror, except for the occasional reference to use in fun houses and to viewing anamorphic art.1,2 However, even a cursory treatment reveals its complexity. Holzberlein used an extended object to qualitatively illustrate that images are produced both before and behind a concave cylindrical mirror.3 He also speculated on how this extreme astigmatism results in an observer's dizziness. By considering a simple point object, we make a more detailed analysis of the cylindrical mirror and the dizziness it induces. First, we illustrate how rays from a point object reflect to form not one point image but two line images. Next, we describe how an observer perceives a likeness of the object. Finally, we suggest how confusing depth cues induce dizziness. Although we focus on the concave cylindrical mirror, the discussion is easy to generalize to the convex cylindrical mirror.

  1. A quantitative gas-liquid chromatographic method for the estimation of hecogenin and tigogenin in the leaves, juice and sapogenin concentrates of Agave sisalana.

    PubMed

    Cripps, A L; Blunden, G

    1978-05-01

    A gas-liquid chromatographic method has been devised for the routine estimation of the hecogenin [3beta-hydroxy-(25R)-5beta-spirostan-12-one] and tigogenin [ (25R)-5beta-spirostan-3beta-ol] contents of Agave sisalana leaf and juice samples and of the crude sapogenin concentrates known as "coffee grounds". Because of partial degradation of the sapogenins in the GLC system it was found necessary to acetylate the compounds prior to their estimation. In East African samples the tigogenin proportion of the total sapogenin content is usually about 10%. At this level, the 95% inverse tolerance limits on predicted tigogenin weights are approximately +/- 7%.

  2. Rare-gas liquids - Equation of state and reduced-pressure, reduced-bulk-modulus, and reduced-sound-velocity functions

    NASA Technical Reports Server (NTRS)

    Schlosser, Herbert

    1990-01-01

    This paper is concerned with verification of the applicability of the Vinet et al. (1987) universal equation of state to the liquid phase of the rare-gas elements under pressure. As previously observed in solids and liquids metals, to a good approximation, in the absence of phase transitions, plots of the logarithms of the reduced pressure function, of the reduced sound velocity, and of the reduced bulk modulus, are all linear functions of 1 - X over the entire experimental pressure range. The results obtained on the rare-gas liquids are comparable in accuracy to those obtained in previous work on solids and liquid metals.

  3. Characterization of carbon dioxide transfer in a hollow fiber membrane module as a solution for gas-liquid transfer in microgravity conditions.

    NASA Astrophysics Data System (ADS)

    Farges, Berangere; Duchez, David; Dussap, Claude-Gilles; Cornet, Jean-F.

    In microgravity, one of the major difficulties encountered in closed photosynthetic reactors is the gas-liquid transfer with the necessity to provide CO2 (carbon source, pH control) and to recover the produced O2 . Indeed, reduced gravity is expected to modify gas liquid transfer and liquid phase mixing characteristics inside photobioreactors conceived to regenerate atmosphere of closed life-support systems. To obtain efficient mass transfer conditions and mixing of phases, several solutions are possible: use of rotating reactor (centrifugal field), use of forced, co-current convective reactor with gas-liquid separator and use of membrane modules. In terms of space process engineering, the membrane reactor can be a valuable alternative in which the gas and liquid phases are separated with a selectively permeable membrane. The rate-limiting factors in this reactor were demonstrated to be the surface of membrane A needed for diffusion of gases and the CO2 and O2 mass transfer coefficients in the liquid phase kL. How-ever, the major advantages of the membrane reactor are that it is composed of a hydrophobic membrane (here PTFE) which showed a high hydrophobicity, an important chemical resis-tance, a very long term stability and overall which is favourable to gas transfer. Moreover, the volumetric mass transfer coefficients are sufficiently high to build compact systems with small footprints, no complex rotating devices and lighter weights. This paper describes first the development of a system enabling the accurate characterization of the mass transfer limiting step for a PTFE membrane module. This original technical apparatus, together with a technical assessment of membrane permeability to different gases, is associated with a balance model, determining thus completely the CO2 mass transfer problem between phases. First results are given and discussed for the CO2 mass transfer coefficient CO kL 2 obtained in case of an absorption experiment at pH = 8 using the

  4. Current pulse effects on cylindrical damage experiments

    SciTech Connect

    Kaul, Ann M; Rousculp, Christopher L

    2009-01-01

    A series of joint experiments between LANL and VNIIEF use a VNIIEF-designed helical generator to provide currents for driving a LANL-designed cylindrical spallation experimental load. Under proper driving conditions, a cylindrical configuration allows for a natural recollection of the damaged material. In addition, the damaged material is able to come to a complete stop due to its strength, avoiding application of further forces. Thus far, experiments have provided data about failure initiation of a well-characterized material (aluminum) in a cylindrical geometry, behavior of material recollected after damage from pressures in the damage initiation regime, and behavior of material recollected after complete failure. In addition to post-shot collection of the damaged target material for subsequent metallographic analysis, dynamic in-situ experimental diagnostics include velocimetry and transverse radial radiography. This paper will focus on the effects of tailoring the driving current pulse to obtain the desired data.

  5. Beamtracking in cylindrical and cartesian coordinates

    SciTech Connect

    Schillinger, B.; Weiland, T.

    1997-02-01

    For the design of devices with circular optical axes, e.g. bending magnets or spectrometers, the use of cylindrical coordinates for field calculations could be favourable. Additionally, in case of applications like bending systems with nonorthogonal entry and exit faces, the coupling of cylindrical and cartesian coordinates improves the simulation of fringe fields. In this context we have implemented a consistent coupling between the two coordinate systems and have extended the tracking code of the electromagnetic simulator MAFIA to cylindrical coordinates. This extensions could be of interest for the calculation of transfer maps of ionoptical devices using the tracked particle orbit as reference trajectory and including fringe field effects in a more general manner. We will give a short introduction to the extensions and show some examples for bending systems with nonorthogonal entries.

  6. Laser diode assembly including a cylindrical lens

    DOEpatents

    Snyder, James J.; Reichert, Patrick

    1992-01-01

    The present invention provides a diffraction limited, high numerical aperture (fast) cylindrical microlens. The method for making the microlens is adaptable to produce a cylindrical lens that has almost any shape on its optical surfaces. The cylindrical lens may have a shape, such as elliptical or hyperbolic, designed to transform some particular given input light distribution into some desired output light distribution. In the method, the desired shape is first formed in a glass preform. Then, the preform is heated to the minimum drawing temperature and a fiber is drawn from it. The cross-sectional shape of the fiber bears a direct relation to the shape of the preform from which it was drawn. During the drawing process, the surfaces become optically smooth due to fire polishing.

  7. Laser diode assembly including a cylindrical lens

    DOEpatents

    Snyder, J.J.; Reichert, P.

    1992-01-14

    The present invention provides a diffraction limited, high numerical aperture (fast) cylindrical microlens. The method for making the microlens is adaptable to produce a cylindrical lens that has almost any shape on its optical surfaces. The cylindrical lens may have a shape, such as elliptical or hyperbolic, designed to transform some particular given input light distribution into some desired output light distribution. In the method, the desired shape is first formed in a glass preform. Then, the preform is heated to the minimum drawing temperature and a fiber is drawn from it. The cross-sectional shape of the fiber bears a direct relation to the shape of the preform from which it was drawn. During the drawing process, the surfaces become optically smooth due to fire polishing. 11 figs.

  8. Cylindrical polarization symmetry for nondestructive nanocharacterization

    NASA Astrophysics Data System (ADS)

    Zhan, Qiwen

    2003-07-01

    Recently there is an increasing interest in laser beams with radial symmetry in polarization. Due to the cylindrical symmetry in polarization, these beams have unique focusing properties, which may find wide applications in a variety of nanometer scale applications, including high-resolution metrology, high-density data storage, and multi-functional optical microtool. In this paper, simple method of generating cylindrically polarized beams is presented and their potential applications to nondestructive nano-characterization are discussed. A high resolution surface plasmon microscope and a surface plasmon enhanced apertureless near-field scanning optical microscope are proposed. An automatic scanning microellipsometer that uses the cylindrical symmetry to enhance the signal-to-noise-ratio in high-spatial-resolution ellipsometric measurement will also be presented.

  9. Thermomechanical fracture on pressurized cylindrical vessels

    NASA Astrophysics Data System (ADS)

    Tzou, Robert D. Y.; Chiu, Kwong S.; Beraun, Jorge E.; Chen, Jinn Kuen

    1998-09-01

    This work studies the rapid fracture developed on the surface of a pressurized cylindrical vessel when heated by an intensified energy source. The primary concerns are the interactions between the rapid thermal expansion and the internal pressure that exerts on the interior surface. From a mechanical point of view, the thermal loading tends to develop a crack along the circumferential direction of the cylindrical vessel. The excessive internal pressure established within the cylindrical vessel, on the other hand, tends to develop a crack in the axial direction. Combination of the two mechanisms results in a capricious pattern of rapid fracture that needs to be fully understood in thermal processing. Special features in this work include the dynamics plasticity induced by the combined thermomechanical loading at short times, as well as the temperature-dependent thermomechanical properties that evolve in the load-time history.

  10. Dewetting processes in a cylindrical geometry.

    PubMed

    Callegari, G; Calvo, A; Hulin, J P

    2005-03-01

    Dewetting of liquid films of water-glycerol solutions of different viscosities has been studied experimentally in PVC cylindrical tubes. In contrast with plane surfaces, the dewetting capillary number Ca(vd) increases with the film thickness ho over a large part of the experimental range and follows a same global trend independent of viscosity as a function of ho. This increase is only partly explained by variations of the capillary driving force predicted in a recent theoretical work for a cylindrical geometry. An additional explanation is suggested, based on different spatial distributions of the viscous dissipation in the dewetting bump in the planar and cylindrical geometries. This mechanism is investigated for films of different thicknesses in a numerical model assuming a polynomial variation of the liquid thickness with distance in the bump region.

  11. Design of tunable cylindrical dielectric nanoantenna

    NASA Astrophysics Data System (ADS)

    Devi, Inder; Reena; Kalra, Yogita; Sinha, R. K.

    2016-09-01

    A tunable cylindrical all dielectric optical nanoantenna has been proposed. A silicon nanocylinder of radius 60 nm and height 150 nm has been considered. The azimuthally symmetric, complete forward scattering at first Kerker's condition and backward scattering with minimum forward scattering at second generalized Kerker's condition in near infra-red region has been observed for the proposed design which makes silicon nanocylinder a promising candidate for optical nanoantenna applications. The effect of the dimensions of the dielectric nanocylinder on the scattering properties of the cylindrical nanoantenna has been analyzed using finite element method. We have analyzed that the variation in diameter of nanocylinder has great influence on the strength of interference of electric and magnetic dipolar resonances. Further, we have observed tuning ability of the cylindrical nanoantenna with respect to the variation in its radius.

  12. Variant for estimating the activity of tropical cyclone groups in the world ocean

    NASA Astrophysics Data System (ADS)

    Yaroshevich, M. I.

    2016-12-01

    It is especially important to know the character and the intensity level of tropical cyclone (TC) activity when the system for estimating the cyclonic danger and risk is formed. During seasons of increased cyclonic activity, when several TCs are simultaneously active, the total energy effect of the cyclone group joint action is not estimated numerically. Cyclonic activity is as a rule characterized by the number of TCs that occur in the considered zone. A variant of the criterion, according to which relative cyclonic activity is estimated, is presented.

  13. Self-referenced interferometer for cylindrical surfaces.

    PubMed

    Šarbort, Martin; Řeřucha, Šimon; Holá, Miroslava; Buchta, Zdeněk; Lazar, Josef

    2015-11-20

    We present a new interferometric method for shape measurement of hollow cylindrical tubes. We propose a simple and robust self-referenced interferometer where the reference and object waves are represented by the central and peripheral parts, respectively, of the conical wave generated by a single axicon lens. The interferogram detected by a digital camera is characterized by a closed-fringe pattern with a circular carrier. The interference phase is demodulated using spatial synchronous detection. The capabilities of the interferometer are experimentally tested for various hollow cylindrical tubes with lengths up to 600 mm.

  14. Cylindrical roller bearings with profiled contacting surfaces

    NASA Astrophysics Data System (ADS)

    Creţu, S. S.

    2017-02-01

    An initial loading of cylindrical roller bearings in the elastic-plastic domain was performed to induce elastic shakedown phenomena able to change the basic profiles of both, rollers and raceways, which endorses a different value for the basic reference rating life. Fatigue life tests carried out on four lots of NJ206 cylindrical roller bearings revealed much higher values of L10 and Lm criteria for the bearings lots which experienced a suitable initial loading operation in the elastic-plastic domain. The reference rating lives, evaluated by using the lamina technique, confirmed the superiority of bearings lots which undergone an appropriate primary loading in the elastic-plastic domain.

  15. Impact of cyclone Nilam on tropical lower atmospheric dynamics

    NASA Astrophysics Data System (ADS)

    Vinay Kumar, P.; Dutta, Gopa; Ratnam, M. V.; Krishna, E.; Bapiraju, B.; Rao, B. Venkateswara; Mohammad, Salauddin

    2016-08-01

    A deep depression formed over the Bay of Bengal on 28 October 2012, and developed into a cyclonic storm. After landfall near the south coast of Chennai, cyclone Nilam moved north-northwestwards. Coordinated experiments were conducted from the Indian stations of Gadanki (13.5°N, 79.2°E) and Hyderabad (17.4°N, 78.5°E) to study the modification of gravity-wave activity and turbulence by cyclone Nilam, using GPS radiosonde and mesosphere-stratosphere-troposphere radar data. The horizontal velocities underwent large changes during the closest approach of the storm to the experimental sites. Hodograph analysis revealed that inertia gravity waves (IGWs) associated with the cyclone changed their directions from northeast (control time) to northwest following the path of the cyclone. The momentum flux of IGWs and short-period gravity waves (1-8 h) enhanced prior to, and during, the passage of the storm (±0.05 m2 s-2 and ±0.3 m2 s-2, respectively), compared to the flux after its passage. The corresponding body forces underwent similar changes, with values ranging between ±2-4 m s-1 d-1 and ±12-15 m s-1 d-1. The turbulence refractivity structure constant ( C n 2 ) showed large values below 10 km before the passage of the cyclone when humidity in the region was very high. Turbulence and humidity reduced during the passage of the storm when a turbulent layer at ~17 km became more intense. Turbulence in the lower troposphere and near the tropopause became weak after the passage of the cyclone.

  16. Tropical cyclones in reanalysis data sets

    NASA Astrophysics Data System (ADS)

    Murakami, Hiroyuki

    2014-03-01

    This study evaluates and compares tropical cyclones (TCs) in state-of-the-art reanalysis data sets including the following: the Japanese 55-year Reanalysis (JRA-55), Japanese 25-year Reanalysis, European Centre for Medium-Range Weather Forecasts Reanalysis-40, Interim Reanalysis, National Centers for Environmental Prediction Climate Forecast System Reanalysis, and NASA's Modern Era Retrospective Analysis for Research and Application (MERRA). Most of the reanalyses reproduce a reasonable global spatial distribution of observed TCs and temporal interannual variation of total TC frequency. Of the six reanalysis data sets, JRA-55 appears to be the best in terms of the following: the highest skill for spatial and temporal distribution of TC frequency of occurrence, highest TC hitting rate, lower false alarm rate, reasonable TC structure in terms of the relationship between maximum surface wind speed and sea level pressure, and higher correlation coefficients for interannual variations of TC frequency. These results also suggest that the finest-resolution reanalysis data sets, like MERRA, are not always the best in terms of TC climatology.

  17. Observed strong currents under global tropical cyclones

    NASA Astrophysics Data System (ADS)

    Chang, Yu-Chia; Tseng, Ruo-Shan; Chu, Peter C.; Chen, Jau-Ming; Centurioni, Luca R.

    2016-07-01

    Global data from drifters of the Surface Velocity Program (Niiler, 2001) and tropical cyclones (TCs) from the Joint Typhoon Warning Center and National Hurricane Center were analyzed to demonstrate strong ocean currents and their characteristics under various storm intensities in the Northern Hemisphere (NH) and in the Southern Hemisphere (SH). Mean TC's translation speed (Uh) is faster in the NH (~ 4.7 m s- 1) than in the SH (~ 4.0 m s- 1), owing to the fact that TCs are more intense in the NH than in the SH. The rightward (leftward) bias of ocean mixed-layer (OML) velocity occurs in the NH (SH). As a result of this slower Uh and thus a smaller Froude number in the SH, the flow patterns in the SH under the same intensity levels of TCs are more symmetric relative to the TC center and the OML velocities are stronger. This study provides the first characterization of the near-surface OML velocity response to all recorded TCs in the SH from direct velocity measurements.

  18. Diurnal Variations of Clouds in Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Wu, Qiaoyan; Ruan, Zhenxin

    2016-04-01

    Using 14 years (2000-2013) of pixel-resolution infrared (IR) brightness temperature data and best track data, this study estimates the diurnal variations of convective systems in tropical cyclones (TCs) in the western North Pacific. The very cold cloud cover (IR brightness temperatures < 208 K) of TCs reaches a maximum areal extent in the early morning (0000-0300 LST) and then decreases after the sunrise. The decrease of very cold cloud cover is followed by an increase of cloud cover between 208 K and 240 K with a maximum areal extent in the afternoon (1500-1800 LST). TC IR cloud top temperatures < 240 K have minimum values in the morning (0300-0600 LST) , while TC IR cloud top temperatures > 240 K have mean minimum values in the afternoon (1500-1800 LST). The out-of-phase relation between different cloud conditions with IR cloud top temperatures < 240 K and IR cloud top temperatures > 240 K lead to radius-averaged IR temperature show two minima within a day. Different diurnal evolution under different cloud conditions suggests that TC convective systems are better described in terms of both areal extent and cloud-top temperature. The maximum cloud cover with IR cloud top temperatures colder than 208 K in the morning and the maximum cloud cover with IR cloud top temperatures between 208 K and 240 K in the afternoon suggest that two different mechanisms might be involved with the diurnal variations of these two types of TC cloud conditions.

  19. Topographic Rossby Waves Generated by Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Dukhovskoy, D. S.; Morey, S. L.

    2013-05-01

    Analytical and numerical studies suggest that given appropriate slope, the ocean responds to a tropical storm with low-frequency motions trapped over a continental slope, the Coastal Trapped Waves. The presented study is focused on Topographic Rossby Waves (TRW), sub-inertial oscillations propagating over a sloping bottom. Generation and propagation of TRW under barotropic (Continental Shelf Waves or Shelf Waves) and baroclinic (Bottom Trapped Waves) approximations are discussed. A real-case model study of a storm surge in Apalachee Bay, northeastern Gulf of Mexico during Hurricane Dennis (July, 2005) is presented to demonstrate the role of the shelf waves in coastal inundation. The presentation also discusses excitation of baroclinic bottom-intensified wave motions on the continental slope by a tropical cyclone. An idealized model experiment demonstrates that a continental shelf that (1) responds to a storm as a baroclinic ocean and (2) has a slope steep enough to dominate the planetary β-effect (but small enough to prevent internal Kelvin-type modes) can support baroclinic topographic waves.

  20. Contrasting tropical cyclone and non-tropical cyclone related rainfall drop size distribution at Darwin, Australia

    NASA Astrophysics Data System (ADS)

    Deo, Anil; Walsh, Kevin J. E.

    2016-11-01

    In this study the rainfall drop size distribution (DSD) during the passage of seven tropical cyclones (TCs) over Darwin is compared and contrasted with that associated with non-tropical cyclone (non-TC) events, using the impact disdrometer data at the Darwin Atmospheric Radiation and Measurement (ARM) site. The disparity of the DSD with respect to rainfall types (between TC and non-TC conditions) and distance from TC centre is also examined. It is shown that TC DSDs are statistically different from the non-TC DSDs, the former encompassing a larger concentration of small to moderate drop sizes. The TC mass-weighted mean diameter (Dm) is lower than the non-TC values at all rain rates and also for the different precipitation types (convective, transition and stratiform). The TC DSD varies with distance from the TC centre, as rainfall near the TC centre (< 60 km) comprises of relatively smaller drops which are strongly evident at small to moderate rain rates (< 30 mm h- 1). Such variations in the DSD have implications for the parameters used in the algorithm that converts radar reflectivity to rainfall rate in TCs, as well as for the analytical expressions used in describing the observed DSD employed in cloud modelling parameterizations.

  1. Floating growth of large-scale freestanding TiO2 nanorod films at the gas-liquid interface for additive-free Li-ion battery applications.

    PubMed

    Xia, Hua-Rong; Li, Jia; Peng, Chen; Sun, Wen-Tao; Li, Long-Wei; Peng, Lian-Mao

    2014-10-22

    The floating growth process of large-scale freestanding TiO2 nanorod films at the gas-liquid interface was investigated. On the basis of the experiments, a self-templated growth scenario was developed to account for the self-assembly process. In the scenario, titanium complexes function not only as the Ti source for the growth of TiO2 but also as a soft template provider for the floating growth. According to the scenario, several new recipes of preparing freestanding TiO2 nanorod films at the gas-liquid interface were developed. The freestanding film was applied to a lithium ion battery as a binder-free and conducting agent-free anode, and good cyclability was obtained. This work may pave a new way to floating and freestanding TiO2 and other semiconductor materials, which has great potential not only in basic science but also in the applications such as materials engineering, Li-ion battery, photocatalyst, dye-sensitized solar cell, and flexible electronics.

  2. Gas-liquid transfer data used to analyze hydrophobic hydration and find the nature of the Kauzmann-Tanford hydrophobic factor.

    PubMed

    Baldwin, Robert L

    2012-05-08

    Hydrophobic free energy for protein folding is currently measured by liquid-liquid transfer, based on an analogy between the folding process and the transfer of a nonpolar solute from water into a reference solvent. The second part of the analogy (transfer into a nonaqueous solvent) is dubious and has been justified by arguing that transfer out of water probably contributes the major part of the free energy change. This assumption is wrong: transfer out of water contributes no more than half the total, often less. Liquid-liquid transfer of the solute from water to liquid alkane is written here as the sum of 2 gas-liquid transfers: (i) out of water into vapor, and (ii) from vapor into liquid alkane. Both gas-liquid transfers have known free energy values for several alkane solutes. The comparable values of the two different transfer reactions are explained by the values, determined in 1991 for three alkane solutes, of the cavity work and the solute-solvent interaction energy. The transfer free energy is the difference between the positive cavity work and the negative solute-solvent interaction energy. The interaction energy has similar values in water and liquid alkane that are intermediate in magnitude between the cavity work in water and in liquid alkane. These properties explain why the transfer free energy has comparable values (with opposite signs) in the two transfers. The current hydrophobic free energy is puzzling and poorly defined and needs a new definition and method of measurement.

  3. Influence of the gas-liquid flow configuration in the absorption column on photosynthetic biogas upgrading in algal-bacterial photobioreactors.

    PubMed

    Toledo-Cervantes, Alma; Madrid-Chirinos, Cindy; Cantera, Sara; Lebrero, Raquel; Muñoz, Raúl

    2017-02-01

    The potential of an algal-bacterial system consisting of a high rate algal pond (HRAP) interconnected to an absorption column (AC) via recirculation of the cultivation broth for the upgrading of biogas and digestate was investigated. The influence of the gas-liquid flow configuration in the AC on the photosynthetic biogas upgrading process was assessed. AC operation in a co-current configuration enabled to maintain a biomass productivity of 15gm(-2)d(-1), while during counter-current operation biomass productivity decreased to 8.7±0.5gm(-2)d(-1) as a result of trace metal limitation. A bio-methane composition complying with most international regulatory limits for injection into natural gas grids was obtained regardless of the gas-liquid flow configuration. Furthermore, the influence of the recycling liquid to biogas flowrate (L/G) ratio on bio-methane quality was assessed under both operational configurations obtaining the best composition at an L/G ratio of 0.5 and co-current flow operation.

  4. Chemical absorption process for degradation of VOC gas using heterogeneous gas-liquid photocatalytic oxidation: toluene degradation by photo-Fenton reaction.

    PubMed

    Tokumura, Masahiro; Nakajima, Rina; Znad, Hussein Tawfeek; Kawase, Yoshinori

    2008-10-01

    A novel process for degradation of toluene in the gas-phase using heterogeneous gas-liquid photocatalytic oxidation has been developed. The degradation of toluene gas by photo-Fenton reaction in the liquid-phase has experimentally examined. The photo-Fenton reaction in the liquid-phase could improve the overall toluene absorption rate by increasing the driving force for mass transfer and as a result enhance the removal of toluene in the exhaust gas. The toluene concentrations in the inlet gas were varied in the range from 0.0968 to 8.69 g m(-3) with initial hydrogen peroxide concentration of 400 mg l(-1) and Fe dose of 5.0 mg l(-1). It was found that toluene in the inlet gas was almost completely dissolved into water and degraded in the liquid-phase for the inlet toluene gas concentration of less than 0.42 g m(-3). The dynamic process of toluene gas degradation by the photo-Fenton reaction providing information for reaction kinetics and mass transfer rate was examined. Toluene removal kinetic analysis indicated that photo-Fenton degradation was significantly affected by H(2)O(2) concentration. The experimental results were satisfactorily described by the predictions simulated using the simplified tanks-in-series model combined with toluene removal kinetic analysis. The present results showed that the proposed chemical absorption process using the photo-Fenton heterogeneous gas-liquid photocatalytic oxidation is very effective for degradation of volatile organic gases.

  5. Gas-liquid transfer data used to analyze hydrophobic hydration and find the nature of the Kauzmann-Tanford hydrophobic factor

    PubMed Central

    Baldwin, Robert L.

    2012-01-01

    Hydrophobic free energy for protein folding is currently measured by liquid-liquid transfer, based on an analogy between the folding process and the transfer of a nonpolar solute from water into a reference solvent. The second part of the analogy (transfer into a nonaqueous solvent) is dubious and has been justified by arguing that transfer out of water probably contributes the major part of the free energy change. This assumption is wrong: transfer out of water contributes no more than half the total, often less. Liquid-liquid transfer of the solute from water to liquid alkane is written here as the sum of 2 gas-liquid transfers: (i) out of water into vapor, and (ii) from vapor into liquid alkane. Both gas-liquid transfers have known free energy values for several alkane solutes. The comparable values of the two different transfer reactions are explained by the values, determined in 1991 for three alkane solutes, of the cavity work and the solute-solvent interaction energy. The transfer free energy is the difference between the positive cavity work and the negative solute-solvent interaction energy. The interaction energy has similar values in water and liquid alkane that are intermediate in magnitude between the cavity work in water and in liquid alkane. These properties explain why the transfer free energy has comparable values (with opposite signs) in the two transfers. The current hydrophobic free energy is puzzling and poorly defined and needs a new definition and method of measurement. PMID:22529345

  6. Preliminary characterization of carbon dioxide transfer in a hollow fiber membrane module as a possible solution for gas-liquid transfer in microgravity conditions

    NASA Astrophysics Data System (ADS)

    Farges, Bérangère; Duchez, David; Dussap, Claude-Gilles; Cornet, Jean-François

    2012-01-01

    In microgravity, one of the major challenge encountered in biological life support systems (BLSS) is the gas-liquid transfer with, for instance, the necessity to provide CO2 (carbon source, pH control) and to recover the evolved O2 in photobioreactors used as atmosphere bioregenerative systems.This paper describes first the development of a system enabling the accurate characterization of the mass transfer limiting step for a PTFE membrane module used as a possible efficient solution to the microgravity gas-liquid transfer. This original technical apparatus, together with a technical assessment of membrane permeability to different gases, is associated with a balance model, determining thus completely the CO2 mass transfer problem between phases. First results are given and discussed for the CO2 mass transfer coefficient kLCO obtained in case of absorption experiments at pH 8 using the hollow fiber membrane module. The consistency of the proposed method, based on a gas and liquid phase balances verifying carbon conservation enables a very accurate determination of the kLCO value as a main limiting step of the whole process. Nevertheless, further experiments are still needed to demonstrate that the proposed method could serve in the future as reference method for mass transfer coefficient determination if using membrane modules for BLSS in reduced or microgravity conditions.

  7. Simulation of Extreme Arctic Cyclones in IPCC AR5 Experiments

    NASA Astrophysics Data System (ADS)

    Vavrus, S. J.

    2012-12-01

    Although impending Arctic climate change is widely recognized, a wild card in its expression is how extreme weather events in this region will respond to greenhouse warming. Intense polar cyclones represent one type of high-latitude phenomena falling into this category, including very deep synoptic-scale cyclones and mesoscale polar lows. These systems inflict damage through high winds, heavy precipitation, and wave action along coastlines, and their impact is expected to expand in the future, when reduced sea ice cover allows enhanced wave energy. The loss of a buffering ice pack could greatly increase the rate of coastal erosion, which has already been increasing in the Arctic. These and related threats may amplify if extreme Arctic cyclones become more frequent and/or intense in a warming climate with much more open water to fuel them. This possibility has merit on the basis of GCM experiments, which project that greenhouse forcing causes lower mean sea level pressure (SLP) in the Arctic and a strengthening of the deepest storms over boreal high latitudes. In this study, the latest Coupled Model Intercomparison Project (CMIP5) climate model output is used to investigate the following questions: (1) What are the spatial and seasonal characteristics of extreme Arctic cyclones? (2) How well do GCMs simulate these phenomena? (3) Are Arctic cyclones already showing the expected response to greenhouse warming in climate models? To address these questions, a retrospective analysis is conducted of the transient 20th century simulations among the CMIP5 GCMs (spanning years 1850-2005). The results demonstrate that GCMs are able to reasonably represent extreme Arctic cyclones and that the simulated characteristics do not depend significantly on model resolution. Consistent with observational evidence, climate models generate these storms primarily during winter and within the climatological Aleutian and Icelandic Low regions. Occasionally the cyclones remain very intense

  8. Cylindrical coordinate representation for multiband Hamiltonians

    NASA Astrophysics Data System (ADS)

    Takhtamirov, Eduard

    2012-10-01

    Rotationally invariant combinations of the Brillouin zone-center Bloch functions are used as basis function to express in cylindrical coordinates the valence-band and Kane envelope-function Hamiltonians for wurtzite and zinc-blende semiconductor heterostructures. For cylindrically symmetric systems, this basis allows to treat the envelope functions as eigenstates of the operator of projection of total angular momentum on the symmetry axis, with the operator's eigenvalue conventionally entering the Hamiltonians as a parameter. Complementing the Hamiltonians with boundary conditions for the envelope functions on the symmetry axis, we present for the first time a complete formalism for efficient modeling and description of multiband electron states in low-dimensional semiconductor structures with cylindrical symmetry. To demonstrate the potency of the cylindrical symmetry approximation and establish a criterion of its applicability for actual structures, we map the ground and several excited valence-band states in an isolated wurtzite GaN quantum wire of a hexagonal cross-section to the states in an equivalent quantum wire of a circular cross-section.

  9. Cylindrical Mixing Layer Model in Stellar Jet

    NASA Astrophysics Data System (ADS)

    Choe, Seung-Urn; Yu, Kyoung Hee

    1994-12-01

    We have developed a cylindrical mixing layer model of a stellar jet including cooling effect in order to understand an optical emission mechanism along collimated high velocity stellar jets associated with young stellar objects. The cylindrical results have been calculated to be the same as the 2D ones presented by Canto & Raga(1991) because the entrainment efficiency in our cylindrical model has been obtained to be the same value as the 2D model has given. We have discussed the morphological and physical characteristics of the mixing layers by the cooling effect. As the jet Mach number increases, the initial temperature of the mixing layer goes high because the kinetic energy of the jet partly converts to the thermal energy of the mixing layer. The initial cooling of the mixing layer is very severe, changing its outer boundary radius. A subsequent change becomes adiabatic. The number of the Mach disks in the stellar jet and the total radiative luminosity of the mixing layer, based on our cylindrical calculation, have quite agreed with the observation.

  10. Cylindrical Induction Melter Modicon Control System

    SciTech Connect

    Weeks, G.E.

    1998-04-01

    In the last several years an extensive R{ampersand}D program has been underway to develop a vitrification system to stabilize Americium (Am) and Curium (Cm) inventories at SRS. This report documents the Modicon control system designed for the 3 inch Cylindrical Induction Melter (CIM).

  11. Distributed neural signals on parabolic cylindrical shells

    NASA Astrophysics Data System (ADS)

    Hu, S. D.; Li, H.; Tzou, H. S.

    2013-06-01

    Parabolic cylindrical shells are commonly used as key components in communication antennas, space telescopes, solar collectors, etc. This study focuses on distributed modal neural sensing signals on a flexible simply-supported parabolic cylindrical shell panel. The parabolic cylindrical shell is fully laminated with a piezoelectric layer on its outer surface and the piezoelectric layer is segmented into infinitesimal elements (neurons) to investigate the microscopic distributed neural sensing signals. Since the dominant vibration component of the shell is usually the transverse oscillation, a new transverse mode shape function is defined. Two shell cases, i.e., the ratio of the meridian height to the half span distance of a parabola at 1:4 (shallow) and 1:1 (deep), are studied to reveal the curvature effect to the neural sensing signals. Studies suggest that the membrane signal component dominates for lower natural modes and the bending signal component dominates for higher natural modes. The meridional membrane and bending signal components are mostly concentrated on the high-curvature areas, while the longitudinal bending component is mostly concentrated on the relatively flat areas. The concentration behavior becomes more prominent as the parabolic cylindrical shell deepens, primarily resulting from the enhanced membrane effect due to the increased curvature.

  12. Tamm plasmon polaritons in multilayered cylindrical structures

    NASA Astrophysics Data System (ADS)

    Little, C. E.; Anufriev, R.; Iorsh, I.; Kaliteevski, M. A.; Abram, R. A.; Brand, S.

    2012-12-01

    It is shown that cylindrical Bragg reflector structures with either a metal core, a metal cladding, or both can support Tamm plasmon polaritons (TPPs) that can propagate axially along the interface between the metallic layer and the adjacent dielectric. A transfer matrix formalism for cylindrical multilayered structures is used in association with cavity phase matching considerations to design structures that support Tamm plasmon polaritons at specified frequencies, and to explore the field distributions and the dispersion relations of the excitations. The cylindrical TPPs can exist in both the TE and TM polarizations for the special cases of modes with either azimuthal isotropy or zero axial propagation constant and also as hybrid cylindrical modes when neither of those conditions applies. In the cases considered the TPPs have low effective masses and low group velocities. Also, when there is both metallic core and cladding, near degenerate modes localized at each metallic interface can couple to produce symmetric and antisymmetric combinations whose frequency difference is in the terahertz regime.

  13. Study of Co-Current and Counter-Current Gas-Liquid Two-Phase Flow Through Packed Bed in Microgravity

    NASA Astrophysics Data System (ADS)

    Revankar, Shripad T.

    2002-11-01

    The main goal of the project is to obtain new experimental data and development of models on the co-current and counter-current gas-liquid two-phase flow through a packed bed in microgravity and characterize the flow regime transition, pressure drop, void and interfacial area distribution, and liquid hold up. Experimental data will be obtained for earth gravity and microgravity conditions. Models will be developed for the prediction of flow regime transition, void fraction distribution and interfacial area concentration, which are key parameters to characterize the packed bed performance. Thus the specific objectives of the proposed research are to: (1) Develop experiments for the study of the gas liquid two-phase flow through the packed bed with three different flow combinations: co-current down flow, co-current upflow and counter current flow. (2) Develop pore scale and bed scale two-phase instrumentation for measurement of flow regime transition, void distribution and gas-liquid interfacial area concentration in the packed bed. (3) Obtain database on flow regime transition, pressure drop, void distribution, interfacial area concentration and liquid hold up as a function of bed characteristics such as bed particle size, porosity, and liquid properties such as viscosity and surface tension. (4) Develop mathematical model for flow regime transition, void fraction distribution and interfacial area concentration for co-current gas-liquid flow through the porous bed in gravity and micro gravity conditions.(4) Develop mathematical model for the flooding phenomena in counter-current gas-liquid flow through the porous bed in gravity and micro gravity conditions. The present proposal addresses the most important topic of HEDS-specific microgravity fluid physics research identified by NASA 's one of the strategic enterprises, OBPR Enterprise. The proposed project is well defined and makes efficient use of the ground-based parabolic flight research aircraft facility. The

  14. Risk factors for mortality in the Bangladesh cyclone of 1991.

    PubMed

    Bern, C; Sniezek, J; Mathbor, G M; Siddiqi, M S; Ronsmans, C; Chowdhury, A M; Choudhury, A E; Islam, K; Bennish, M; Noji, E

    1993-01-01

    Cyclones continue to pose a dangerous threat to the coastal populations of Bangladesh, despite improvements in disaster control procedures. After 138,000 persons died in the April 1991 cyclone, we carried out a rapid epidemiological assessment to determine factors associated with cyclone-related mortality and to identify prevention strategies. A nonrandom survey of 45 housing clusters comprising 1123 persons showed that mortality was greatest among under-10-year-olds (26%) and women older than 40 years (31%). Nearly 22% of persons who did not reach a concrete or brick structure died, whereas all persons who sought refuge in such structures survived. Future cyclone-associated mortality in Bangladesh could be prevented by more effective warnings leading to an earlier response, better access to designated cyclone shelters, and improved preparedness in high-risk communities. In particular, deaths among women and under-10-year-olds could be reduced by ensuring that they are given special attention by families, neighbours, local authorities, and especially those in charge of early warnings and emergency evacuation.

  15. A sensitivity study of storm cyclones with a mesoscale model

    NASA Astrophysics Data System (ADS)

    Radtke, K. S.; Tetzlaff, G.

    2003-04-01

    Extra tropical storms caused noticeable damages in the last decades. The evolution of strong cyclones is investigated by simulations with the nonhydrostatic limited area model 'Lokal Modell' (LM) of the German Weather Service (DWD). Which Conditions become important to distinguish an common cyclone from an storm-cyclone? Intense cyclones are mostly characterised by two typical large-scale features: high baroclinicity along the track of the low pressure system and a region of high equivalent potential temperature. For this purpose the observed values of the horizontal temperature gradient and the distribution of air moisture are varied and were used as forcing data, in such a way the development of storms was modified. The forcing data for the LM were generated by the global model of the DWD. Therefore data of real cyclones, such as the low Ginger, which occurred in 2000, were used. As the LM simulates only a limited area, the lateral bounds become problematic because of the manipulated forcing data. A procedure is tested, in order to prevent these problems. In this manner ensembles of storm scenarios were produced. The effects of various conditions were studied. Here in particular the changes in the surface velocity field were of interest. In the case of Ginger, an increase of the temperature gradient about 10 K causes an increasing of the maximum velocity about 3 m/s.

  16. The hurricane-like Mediterranean cyclone of January 1995

    NASA Astrophysics Data System (ADS)

    Pytharoulis, Ioannis; Craig, George; Ballard, Susan

    2000-09-01

    The development of a hurricane-like vortex over the Mediterranean Sea was studied using (mainly) the UK Met. Office Unified Model. The Mediterranean cyclone formed in the morning of 15 January 1995 over the sea between Greece and Sicily. Strong convection was observed prior to its genesis. During the longest part of the cyclone's lifetime, strong surface fluxes and, as a result, deep convection existed in its vicinity. Its track was influenced by the surface fluxes and the flow in the wider region. The forecast of the mesoscale and limited-area models reproduced the general characteristics of the actual system as they appeared at the surface and upper-air charts and at the satellite imagery. The investigation of the cyclone's characteristics gave strong evidence (including an ‘eye’ and a warm core) to support the initial assertion that it was similar to tropical cyclones and some polar lows. Baroclinic instability does not seem particularly important, although the cyclone formed at the edge of a baroclinic zone. A numerical experiment showed the vortex did not develop in the absence of surface heat and moisture fluxes. Another experiment showed that sensible and latent heat fluxes were equally important in its development.

  17. Opposed-flow virtual cyclone for particle concentration

    DOEpatents

    Rader, Daniel J.; Torczynski, John R.

    2000-12-05

    An opposed-flow virtual cyclone for aerosol collation which can accurately collect, classify, and concentrate (enrich) particles in a specific size range. The opposed-flow virtual cyclone is a variation on the virtual cyclone and has its inherent advantages (no-impact particle separation in a simple geometry), while providing a more robust design for concentrating particles in a flow-through type system. The opposed-flow virtual cyclone consists of two geometrically similar virtual cyclones arranged such that their inlet jets are inwardly directed and symmetrically opposed relative to a plane of symmetry located between the two inlet slits. A top plate bounds both jets on the "top" side of the inlets, while the other or lower wall curves "down" and away from each inlet jet. Each inlet jet will follow the adjacent lower wall as it turns away, and that particles will be transferred away from the wall and towards the symmetry plane by centrifugal action. After turning, the two jets merge smoothly along the symmetry line and flow parallel to it through the throat. Particles are transferred from the main flows, across a dividing streamline, and into a central recirculating region, where particle concentrations become greatly increased relative to the main stream.

  18. Cloud Condensation Nuclei Measurements in Tropical Cyclones

    NASA Astrophysics Data System (ADS)

    Hudson, J. G.; Simpson, J.

    2002-05-01

    The first measurements of cloud condensation nuclei (CCN) within and around tropical cyclones were made with the Desert Research Institute (DRI) CCN spectrometer (Hudson 1989) from a NOAA P-3 Hurricane Hunter aircraft throughout the 2001 season. Two penetrations of the closed eye of Hurricane Erin off the northeast US coast on Sept. 10 showed concentrations consistently well in excess of 1000 per cubic cm at approximately 1.4% supersaturation. Simultaneous condensation nuclei (CN--total particle) concentrations were consistently well in excess of 2000 per cubic cm throughout these closed eye penetrations. These within eye measurements at 4 km altitude far exceeded CCN and CN measurements just outside of the storm at similar altitudes--300 and 600 per cubic cm respectively. These CCN and CN concentrations within this closed eye were far above concentrations in maritime air masses; they are characteristic of continental or polluted air masses. Although there was a possibility that Saharan dust may have gotten into this storm these sub tenth micrometer particles are much too small and much too numerous to be dust. Such high concentrations may have originated from European air pollution, which may have been transported by similar airflow patterns to those that carry Saharan dust across the Atlantic. These high concentrations may be a manifestation of descending air that brings higher concentrations that are often characteristic of the upper troposphere (Clarke and Kapustin 2002). Later in the month measurements in Humberto showed highly variable CCN and CN concentrations that ranged from less than 5 per cubic cm to more than 1000 per cubic cm over km scale distances within and around the open eye of this tropical storm/hurricane. These very low concentrations suggest strong cloud scavenging. Clarke, A.D. and V.N. Kapustin, J. Atmos. Sci., 59, 363-382, 2002. Hudson, J.G., J. Atmos. & Ocean. Tech., 6, 1055-1065, 1989.

  19. Satellite-based Tropical Cyclone Monitoring Capabilities

    NASA Astrophysics Data System (ADS)

    Hawkins, J.; Richardson, K.; Surratt, M.; Yang, S.; Lee, T. F.; Sampson, C. R.; Solbrig, J.; Kuciauskas, A. P.; Miller, S. D.; Kent, J.

    2012-12-01

    Satellite remote sensing capabilities to monitor tropical cyclone (TC) location, structure, and intensity have evolved by utilizing a combination of operational and research and development (R&D) sensors. The microwave imagers from the operational Defense Meteorological Satellite Program [Special Sensor Microwave/Imager (SSM/I) and the Special Sensor Microwave Imager Sounder (SSMIS)] form the "base" for structure observations due to their ability to view through upper-level clouds, modest size swaths and ability to capture most storm structure features. The NASA TRMM microwave imager and precipitation radar continue their 15+ yearlong missions in serving the TC warning and research communities. The cessation of NASA's QuikSCAT satellite after more than a decade of service is sorely missed, but India's OceanSat-2 scatterometer is now providing crucial ocean surface wind vectors in addition to the Navy's WindSat ocean surface wind vector retrievals. Another Advanced Scatterometer (ASCAT) onboard EUMETSAT's MetOp-2 satellite is slated for launch soon. Passive microwave imagery has received a much needed boost with the launch of the French/Indian Megha Tropiques imager in September 2011, basically greatly supplementing the very successful NASA TRMM pathfinder with a larger swath and more frequent temporal sampling. While initial data issues have delayed data utilization, current news indicates this data will be available in 2013. Future NASA Global Precipitation Mission (GPM) sensors starting in 2014 will provide enhanced capabilities. Also, the inclusion of the new microwave sounder data from the NPP ATMS (Oct 2011) will assist in mapping TC convective structures. The National Polar orbiting Partnership (NPP) program's VIIRS sensor includes a day night band (DNB) with the capability to view TC cloud structure at night when sufficient lunar illumination exits. Examples highlighting this new capability will be discussed in concert with additional data fusion efforts.

  20. Cloud Condensation Nuclei Measurements in Tropical Cyclones

    NASA Technical Reports Server (NTRS)

    Hudson, J. G.; Simpson, J.

    2002-01-01

    The first measurements of cloud condensation nuclei (CCN) within and around tropical cyclones were made with the Desert Research Institute (DRI) CCN spectrometer (Hudson 1909) from a NOAA P-3 Hurricane Hunter aircraft throughout the 2001 season. Two penetrations of the closed eye of Hurricane Erin off the northeast US coast on Sept. 10 showed concentrations consistently well in excess of 1000 per cubic cm at approximately 1.4% supersaturation. Simultaneous condensation nuclei (CN--total particle) concentrations were consistently well in excess of 2000 per cubic cm throughout these closed eye penetrations. These within eye measurements at 4 km altitude for exceeded CCN and CN measurements just outside of the storm at similar altitudes--300 and 600 per cubic cm respectively. These CCN and CN concentrations within this closed eye were far above concentrations in maritime air masses; they are characteristic of continental or polluted air masses. Although there was a possibility that Saharan duct may have gotten into this storm these sub tenth micrometer particles are much too small and much too numerous to be dust. Such high concentrations may have originated from European air pollution, which may have been transported by similar airflow patterns to those that carry Saharan dust across the Atlantic. These high concentrations may be a manifestation of descending air that brings higher concentrations that are often characteristic of the upper troposphere (Clarke and Kapustin 2002). Later in the month measurements in Humberto showed highly variable CCN and CN concentrations that ranged from lots than 5 per cubic cm to more than 1000 per Cubic cm over km scale distances within and around the open eye of this tropical storm/hurricane. These very low concentrations suggest strong cloud scavenging.

  1. Impact of SST resolution on cyclone activity over the Kuroshio

    NASA Astrophysics Data System (ADS)

    Iizuka, S.; Kawamura, R.

    2012-12-01

    The impact of high resolution sea surface temperature (SST) data on the winter time cyclone activity around Japan is investigated using a WRF model with a horizontal resolution of 20 km. A fine scale SST and a smoothed one of that SST are used as the lower boundary condition in the experiments. Generally, a fine scale SST is warmer in the south of the Polar Front over the Japan Sea, the Kuroshio/Oyashio extension, and the coastal regions around Japan comparing with the smoothed SST because the former resolves the small scale features in the SST related to ocean currents. In comparison, the smoothed SST weakened the simulated cyclones passing over the Kuroshio near the Ryukyu Islands. This may be due to the weaker surface baroclinicity associated with the smoothed SST. The similar features are found around the Polar Front over the Japan Sea. The results imply a potential impact of SST gradients on cyclone activity.

  2. Impact of Vertical Wind Shear on Tropical Cyclone Rainfall

    NASA Technical Reports Server (NTRS)

    Cecil, Dan; Marchok, Tim

    2014-01-01

    While tropical cyclone rainfall has a large axisymmetric component, previous observational and theoretical studies have shown that environmental vertical wind shear leads to an asymmetric component of the vertical motion and precipitation fields. Composites consistently depict a precipitation enhancement downshear and also cyclonically downwind from the downshear direction. For consistence with much of the literature and with Northern Hemisphere observations, this is subsequently referred to as "Downshear-Left". Stronger shear magnitudes are associated with greater amplitude precipitation asymmetries. Recent work has reinforced the prior findings, and explored details of the response of the precipitation and kinematic fields to environmental vertical wind shear. Much of this research has focused on tropical cyclones away from land, to limit the influence of other processes that might distort the signal related to vertical wind shear. Recent evidence does suggest vertical wind shear can also play a major role in precipitation asymmetries during and after landfall.

  3. Preliminary abatement device evaluation: 1D-2D KGM cyclone design

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cyclones are predominately used in controlling cotton gin particulate matter (PM) emissions. The most commonly used cyclone designs are the 2D-2D and 1D-3D; however other designs such as the 1D-2D KGM have or are currently being used. A 1D-2D cyclone has a barrel length equal to the barrel diamete...

  4. Revisiting the steering principal of tropical cyclone motion in a numerical experiment

    NASA Astrophysics Data System (ADS)

    Wu, Liguang; Chen, Xiaoyu

    2016-12-01

    The steering principle of tropical cyclone motion has been applied to tropical cyclone forecasting and research for nearly 100 years. Two fundamental questions remain unanswered. One is why the steering flow plays a dominant role in tropical cyclone motion, and the other is when tropical cyclone motion deviates considerably from the steering. A high-resolution numerical experiment was conducted with the tropical cyclone in a typical large-scale monsoon trough over the western North Pacific. The simulated tropical cyclone experiences two eyewall replacement processes. Based on the potential vorticity tendency (PVT) diagnostics, this study demonstrates that the conventional steering, which is calculated over a certain radius from the tropical cyclone center in the horizontal and a deep pressure layer in the vertical, plays a dominant role in tropical cyclone motion since the contributions from other processes are largely cancelled out due to the coherent structure of tropical cyclone circulation. Resulting from the asymmetric dynamics of the tropical cyclone inner core, the trochoidal motion around the mean tropical cyclone track cannot be accounted for by the conventional steering. The instantaneous tropical cyclone motion can considerably deviate from the conventional steering that approximately accounts for the combined effect of the contribution of the advection of the symmetric potential vorticity component by the asymmetric flow and the contribution from the advection of the wave-number-one potential vorticity component by the symmetric flow.

  5. Demonstration of coal reburning for cyclone boiler NO{sub x} control. Appendix, Book 1

    SciTech Connect

    Not Available

    1994-06-01

    Based on the industry need for a pilot-scale cyclone boiler simulator, Babcock Wilcox (B&W) designed, fabricated, and installed such a facility at its Alliance Research Center (ARC) in 1985. The project involved conversion of an existing pulverized coal-fired facility to be cyclone-firing capable. Additionally, convective section tube banks were installed in the upper furnace in order to simulate a typical boiler convection pass. The small boiler simulator (SBS) is designed to simulate most fireside aspects of full-size utility boilers such as combustion and flue gas emissions characteristics, fireside deposition, etc. Prior to the design of the pilot-scale cyclone boiler simulator, the various cyclone boiler types were reviewed in order to identify the inherent cyclone boiler design characteristics which are applicable to the majority of these boilers. The cyclone boiler characteristics that were reviewed include NO{sub x} emissions, furnace exit gas temperature (FEGT) carbon loss, and total furnace residence time. Previous pilot-scale cyclone-fired furnace experience identified the following concerns: (1) Operability of a small cyclone furnace (e.g., continuous slag tapping capability). (2) The optimum cyclone(s) configuration for the pilot-scale unit. (3) Compatibility of NO{sub x} levels, carbon burnout, cyclone ash carryover to the convection pass, cyclone temperature, furnace residence time, and FEGT.

  6. An Experimental Investigation of the Flow in a Virtual Cyclone

    SciTech Connect

    Torczynski, J.R.; O'Hern, T.J.; Rader, D.J.; Brockmann, J.E.; Grasser, T.W.

    1998-09-01

    An experimental investigation has confirmed the predicted flow pattern in a prototype virtual cyclone, a novel device for nonimpact particle separation proposed by Torcdzynski and Rader (1996, 1997) based solely on computational simulations. The virtual cyclone differs from an ordinary cyclone in that the flow is turned by a virtual wall composed of an eddy rather than by a solid wall. A small-scale version of the computationally simulated geometry has been fabricated out of Lucite. The working fluid is ambient air, which is drawn through the apparatus and flow-metering equipment using a wind-tunnel vacuum source. The flow is seeded with smoke or water droplets produced by a nebulizer so that flow visualization techniques and particle-imaging velocimetry could be applied. Experiments have been performed on this apparatus for flows with Reynolds numbers from 200 up to 40,000 (a Mach number of 0.3). Flow visualization using a laser light sheet passing through the mid-plane of the apparatus verified that the computationally predicted flow is obtained over the entire range of flow rates. The shear layer between the main and recirculating flow is observed to become turbulent around a Reynolds number of 4000. While not changing the flow structure, the turbulent mixing produced by shear-layer roll-up limits particle concentration at the higher flow rates. In order to achieve highly efficient particle separation using a virtual cyclone, turbulence must be suppressed or mitigated. If laminar flow cannot be achieved for macroscopic-scale virtual cyclones, it should be achievable for a small-scale (low Reynolds number) virtual cyclone fabricated using MEMS-related technologies. This approach could lead to a chip-scale particle concentrator.

  7. On the Relationship between Tropical Moisture Exports and Extratropical Cyclones

    NASA Astrophysics Data System (ADS)

    Knippertz, Peter; Wernli, Heini; Gläser, Gregor; Boleti, Eirini; Joos, Hanna; Binder, Hanin

    2016-04-01

    Tropical moisture export (TME) events are an important element of the global circulation and contribute significantly to regional precipitation. They are defined here on the basis of trajectories starting in the tropical troposphere and reaching a water vapor flux of at least 100 g kg-1 m s-1 poleward of 35° latitude. TME frequency shows four marked occurrence maxima in both hemispheres with varying seasonal cycles. In some cases TMEs can be linked to similar phenomena of atmospheric flow such as Warm Conveyor Belts (WCBs) or Atmospheric Rivers (ARs). For example, 90% of all ARs affecting the US West Coast during December-May are connected to TME events, but the tropical moisture source is less important during the more active AR season June-November. In addition to these climatological TME characteristics we discuss two aspects of their relationship to extratropical cyclones: Case studies indicate that (i) cyclones traveling along the southern fringes of the midlatitude storm track can instigate the export of tropical moisture ahead of their cold fronts, and (ii) the tropical moisture can fuel latent heat release in the cyclone and therefore contribute to its intensification. A long-term statistical analysis of passages of TME trajectories through areas with closed isobars surrounding active cyclones in the northern hemisphere reveals a surprisingly small number of encounters, particularly in winter. The majority of hits occur south of 40°N and there is no statistically significant relationship with cyclone intensification. The results suggest that TMEs often pass relatively far from cyclone centers where vertical motions tend to be moderate. This prevents an early rainout of the tropical moisture and allows the export into higher latitudes. For the same reasons we expect TMEs to "avoid" WCBs with roots at low latitudes. This interpretation is consistent with the fact that most TME maxima are located along the western flanks of subtropical high-pressure systems.

  8. On the Relationship between Tropical Moisture Exports and Extratropical Cyclones

    NASA Astrophysics Data System (ADS)

    Knippertz, P.; Wernli, H.; Gläser, G.; Boleti, E.; Joos, H.; Binder, H.

    2015-12-01

    Tropical moisture export (TME) events are an important element of the global circulation and contribute significantly to regional precipitation. They are defined here on the basis of trajectories starting in the tropical troposphere and reaching a water vapor flux of at least 100 g kg-1 m s-1 poleward of 35° latitude. TME frequency shows four marked occurrence maxima in both hemispheres with varying seasonal cycles. In some cases TMEs can be linked to similar phenomena of atmospheric flow such as Warm Conveyor Belts (WCBs) or Atmospheric Rivers (ARs). For example, 90% of all ARs affecting the US West Coast during December-May are connected to TME events, but the tropical moisture source is less important during the more active AR season June-November. In addition to these climatological TME characteristics we discuss two aspects of their relationship to extratropical cyclones: Case studies indicate that (i) cyclones traveling along the southern fringes of the midlatitude storm track can instigate the export of tropical moisture ahead of their cold fronts, and (ii) the tropical moisture can fuel latent heat release in the cyclone and therefore contribute to its intensification. A long-term statistical analysis of passages of TME trajectories through areas with closed isobars surrounding active cyclones in the northern hemisphere reveals a surprisingly small number of encounters, particularly in winter. The majority of hits occur south of 40°N and there is no statistically significant relationship with cyclone intensification. The results suggest that TMEs often pass relatively far from cyclone centers where vertical motions tend to be moderate. This prevents an early rainout of the tropical moisture and allows the export into higher latitudes. For the same reasons we expect TMEs to "avoid" WCBs with roots at low latitudes. This interpretation is consistent with the fact that most TME maxima are located along the western flanks of subtropical high-pressure systems.

  9. Training on Eastern Pacific tropical cyclones for Latin American students

    NASA Astrophysics Data System (ADS)

    Farfán, L. M.; Raga, G. B.

    2009-05-01

    Tropical cyclones are one of the most impressive atmospheric phenomena and their development in the Atlantic and Eastern Pacific basins has potential to affect several Latin-American and Caribbean countries, where human resources are limited. As part of an international research project, we are offering short courses based on the current understanding of tropical cyclones in the Eastern Pacific basin. Our main goal is to train students from higher-education institutions from various countries in Latin America. Key aspects are tropical cyclone formation and evolution, with particular emphasis on their development off the west coast of Mexico. Our approach includes lectures on tropical cyclone climatology and formation, dynamic and thermodynamic models, air-sea interaction and oceanic response, ocean waves and coastal impacts as well as variability and climate-related predictions. In particular, we use a best-track dataset issued by the United States National Hurricane Center and satellite observations to analyze convective patterns for the period 1970-2006. Case studies that resulted in landfall over northwestern Mexico are analyzed in more detail; this includes systems that developed during the 2006, 2007 and 2008 seasons. Additionally, we have organized a human-dimensions symposium to discuss socio-economic issues that are associated with the landfall of tropical cyclones. This includes coastal zone impact and flooding, the link between cyclones and water resources, the flow of weather and climate information from scientists to policy- makers, the role of emergency managers and decision makers, impact over health issues and the viewpoint of the insurance industry.

  10. Effects of Cumulus Convection on Rapidly Intensifying Cyclones

    DTIC Science & Technology

    2016-06-07

    Effects Of Cumulus Convection On Rapidly Intensifying Cyclones M.K. Yau and R. R. Rogers Department of Atmospheric and Oceanic Sciences McGill...N00014-96-1-0746 LONG-TERM GOAL Our long term goal is to contribute to our understanding of the physics and dynamics of marine convection and mesoscale...00-00-1999 to 00-00-1999 4. TITLE AND SUBTITLE Effects Of Cumulus Convection On Rapidly Intensifying Cyclones 5a. CONTRACT NUMBER 5b. GRANT NUMBER

  11. Cyclone Nargis and Burma’s Constitutional Referendum

    DTIC Science & Technology

    2008-05-09

    emerge in the aftermath of the cyclone’s flooding.10 CRS-3 11 Mark Kinver, “ Mangrove Loss ‘Left Burma Exposed,’” BBC News, May 6, 2006 12 “ Mangrove ...the cyclone was worsened by the removal of mangrove forests in the past along Burma’s coastal areas.11 In Burma, mangrove forests have been destroyed...coastal mangrove forests saved many lives when the 2004 tsunami struck.12 Based on the research in Sri Lanka, some experts maintain that Cyclone

  12. Tropical cyclone Pam coastal impact survey in Vanuatu

    NASA Astrophysics Data System (ADS)

    Fritz, H. M.; Pilarczyk, J.; Kosciuch, T. J.; Hong, I.; Rarai, A.; Harrison, M. J.; Jockley, F. R.; Horton, B.

    2015-12-01

    Severe tropical cyclone Pam (Cat. 5, SSHS) crossed the Vanuatu archipelago with sustained winds of 270 km/h on March 13 and 14, 2015 and made landfall on Erromango. Pam caused the worst natural disaster in Vanuatu's recorded history since severe tropical cyclone Uma in 1987. Eleven fatalities were directly attributed to cyclone Pam and mostly due to lack of shelter from airborne debris. On March 6 Pam formed east of the Santa Cruz Islands and intensified while tracking southward along Vanuatu severely affecting the Shefa and Tafea Provinces. An international storm surge reconnaissance team was deployed to Vanuatu from June 3 to 17, 2015 to complement earlier local surveys. Cyclone Pam struck a remote island archipelago particularly vulnerable to the combined cyclonic multi-hazards encompassing extreme wind gusts, massive rainfall and coastal flooding due to a combination of storm surge and storm wave impacts. The team surveyed coastal villages on Epi, the Shepherd Islands (Tongoa and Mataso), Efate (including Lelepa), Erromango, and Tanna. The survey spanned 320 km parallel to the cyclone track between Epi and Tanna encompassing more than 45 sites including the hardest hit settlements. Coastal flooding profiles were surveyed from the shoreline to the limit of inundation. Maximum coastal flood elevations and overland flow depths were measured based on water marks on buildings, scars on trees, rafted debris and corroborated with eyewitness accounts. We surveyed 91 high water marks with characteristic coastal flood levels in the 3 to 7 m range and composed of storm surge with superimposed storm waves. Inundation distances were mostly limited to a few hundred meters. Coral boulders of more than 1 m diameter were measured on Erromango and sediment samples were collected at key sites across the archipelago. Infrastructure damage on traditional and modern structures was assessed. Eyewitnesses were interviewed at most sites to document the chronology of the wind and

  13. Wind waves in tropical cyclones: satellite altimeter observations and modeling

    NASA Astrophysics Data System (ADS)

    Golubkin, Pavel; Kudryavtsev, Vladimir; Chapron, Bertrand

    2016-04-01

    Results of investigation of wind-wave generation by tropical cyclones using satellite altimeter data are presented. Tropical cyclones are generally relatively small rapidly moving low pressure systems that are capable of generating severe wave conditions. Translation of a tropical cyclone leads to a prolonged period of time surface waves in the right sector remain under high wind forcing conditions. This effect has been termed extended fetch, trapped fetch or group velocity quasi-resonance. A tropical cyclone wave field is thus likely more asymmetrical than the corresponding wind field: wind waves in the tropical cyclone right sector are more developed with larger heights than waves in the left one. A dataset of satellite altimeter intersections of the Western Pacific tropical cyclones was created for 2010-2013. Data from four missions were considered, i.e., Jason-1, Jason-2, CryoSat-2, SARAL/AltiKa. Measurements in the rear-left and front-right sectors of tropical cyclones were examined for the presence of significant wave asymmetry. An analytical model is then derived to efficiently describe the wave energy distribution in a moving tropical cyclone. The model essentially builds on a generalization of the self-similar wave growth model and the assumption of a strongly dominant single spectral mode in a given quadrant of the storm. The model provides a criterion to anticipate wave enhancement with the generation of trapped abnormal waves. If forced during a sufficient timescale interval, also defined from this generalized self-similar wave growth model, waves can be trapped and large amplification of the wave energy will occur in the front-right storm quadrant. Remarkably, the group velocity and corresponding wavelength of outrunning wave systems will become wind speed independent and solely relate to the translating velocity. The resulting significant wave height also only weakly depends on wind speed, and more strongly on the translation velocity. Satellite

  14. The Role of Interacting Cyclones in Modifying Tropical Cyclone Landfall Threat: Fujiwhara vs. enhanced Beta drift?

    NASA Astrophysics Data System (ADS)

    Hart, R. E.

    2013-12-01

    The recent impacts of tropical cyclones (TCs) Irene and Sandy have brought to the forefront the question of the true return period of landfalls in that region. Given the relatively short period of record of observations, those seeking robust return estimates often generate stochastic event sets. While the details of methods for generating those sets are generally not published (with an exception being Emanuel 2006), presentations have suggested that each member (TC event) of a stochastic set does not impact other TC members. Such an approach has the benefit of relative simplicity as well as rapidity of production, as each TC member can be produced without concern about simultaneous TCs in the basin. Given most real-world TCs are separated by several days or more, and distances of 2000km or more, this approach is seemingly well-founded for the majority of TC climatology. Yet, there have been many examples of TC-TC Fujiwhara interaction across the globe. While the interaction is much more common in the western Pacific, it is not unheard of in the Atlantic - with Connie and Diane in 1955 as two examples of such interaction but largely away from land. Further, the northeast U.S. coast can be threatened through such TC-TC interactions. The historic 1893 New York City Hurricane took an unusual NNW track (and landfall location) possibly as a consequence of interaction with one if not two additional nearby TCs. Numerical model (WRF) simulations of this case revealed exceptional difficulty in track prediction, illustrating further the complexity of the interaction. Interaction is not necessarily limited to another TC. Occasionally, a TC will interact with an occluded cold-core cyclone, which can then take the TC on a highly unusual track. Such interactions by their nature occur most often early or late in the TC season. Examples of TC-nonTC interaction include the 1938 New England Hurricane, Hurricane Hazel from 1950, and most recently, Hurricane Sandy, all of which had

  15. Contributions of Tropical Cyclones to the North Atlantic Climatological Rainfall as Observed from Satellites

    NASA Technical Reports Server (NTRS)

    Rodgers, Edward B.; Adler, Robert F.; Pierce, Harold F.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The tropical cyclone rainfall climatology study that was performed for the North Pacific was extended to the North Atlantic. Similar to the North Pacific tropical cyclone study, mean monthly rainfall within 444 km of the center of the North Atlantic tropical cyclones (i.e., that reached storm stage and greater) was estimated from passive microwave satellite observations during, an eleven year period. These satellite-observed rainfall estimates were used to assess the impact of tropical cyclone rainfall in altering the geographical, seasonal, and inter-annual distribution of the North Atlantic total rainfall during, June-November when tropical cyclones were most abundant. The main results from this study indicate: 1) that tropical cyclones contribute, respectively, 4%, 3%, and 4% to the western, eastern, and entire North Atlantic; 2) similar to that observed in the North Pacific, the maximum in North Atlantic tropical cyclone rainfall is approximately 5 - 10 deg poleward (depending on longitude) of the maximum non-tropical cyclone rainfall; 3) tropical cyclones contribute regionally a maximum of 30% of the total rainfall 'northeast of Puerto Rico, within a region near 15 deg N 55 deg W, and off the west coast of Africa; 4) there is no lag between the months with maximum tropical cyclone rainfall and non-tropical cyclone rainfall in the western North Atlantic, while in the eastern North Atlantic, maximum tropical cyclone rainfall precedes maximum non-tropical cyclone rainfall; 5) like the North Pacific, North Atlantic tropical cyclones Of hurricane intensity generate the greatest amount of rainfall in the higher latitudes; and 6) warm ENSO events inhibit tropical cyclone rainfall.

  16. Cylindrically converging shock and detonation waves

    NASA Astrophysics Data System (ADS)

    Matsuo, H.

    1983-07-01

    The non-self-similar implosion of cylindrical shock and detonation waves generated by an instantaneous energy release at a cylindrical wall is analyzed theoretically by the method of integral relations. The analysis shows that as the wave propagates towards the axis, the solutions tend to approach but never reach the self-similar implosion limit. The rate of approach appears to be slower than expected, and the region of applicability of the self-similar solution appears to be restricted to a very small region behind the front. This tendency is more pronounced for the detonation case. It is also demonstrated that for detonations where the initiation energy is negligible in comparison with the chemical energy, the Chapman-Jouguet detonation jump conditions apply at the front except near the axis and near the outer wall. The chemical heating in the detonation process increases the pressure and the temperature but considerably reduces the density near the front.

  17. Dynamic Buckling of Composite Cylindrical Shells

    NASA Astrophysics Data System (ADS)

    Cheng, Sai-Wei; Wang, Xiao-Jun

    2016-05-01

    Considering the effect of stress wave, the dynamic buckling governing equations and boundary conditions of composite cylindrical shells under axial step load are derived based on the Hamilton principle. The expression of radial displacement function along the circumferential direction is assumed since the cylindrical shell is closed. The solutions of the governing equations are obtained by the state-space technique. The determinant of the coefficient matrix must be equal to zero if the linear equations have a non-trivial solution. The relationship between the critical load and length and the influences of boundary conditions, modes, etc. on critical load are obtained by programming with MATLAB software before and after the reflection of stress wave.

  18. Surface superconductivity in thin cylindrical Bi nanowire.

    PubMed

    Tian, Mingliang; Wang, Jian; Ning, Wei; Mallouk, Thomas E; Chan, Moses H W

    2015-03-11

    The physical origin and the nature of superconductivity in nanostructured Bi remains puzzling. Here, we report transport measurements of individual cylindrical single-crystal Bi nanowires, 20 and 32 nm in diameter. In contrast to nonsuperconducting Bi nanoribbons with two flat surfaces, cylindrical Bi nanowires show superconductivity below 1.3 K. However, their superconducting critical magnetic fields decrease with their diameter, which is the opposite of the expected behavior for thin superconducting wires. Quasiperiodic oscillations of magnetoresistance were observed in perpendicular fields but were not seen in the parallel orientation. These results can be understood by a model of surface superconductivity with an enhanced surface-to-bulk volume in small diameter wires, where the superconductivity originates from the strained surface states of the nanowires due to the surface curvature-induced stress.

  19. Experimental study of cylindrical air electrodes

    NASA Astrophysics Data System (ADS)

    Viitanen, M.; Lamminen, J.; Lampinen, M. J.

    1991-11-01

    The electrodes studied here are cylindrical and prepared to be placed inside the inner surface of a sintered brass tube, which is nickel-plated. Previously we have reported on the preparation of flat air electrodes and also on long run tests carried out with these electrodes. The electrode material was prepared by the so-called wet method to obtain a carbon dough which is easy to handle. The material preparation remains the same, but owing to the different geometrical shape, the preparation of the electrode itself is quite different. We have studied here the long-term performance of these new cylindrical air electrodes and at the same time measured the carbonate content of the electrolyte. We have also analyzed by comparative methods which property of the electrode lowers the performance after a fairly long period.

  20. Variable-focus cylindrical liquid lens array

    NASA Astrophysics Data System (ADS)

    Zhao, Wu-xiang; Liang, Dong; Zhang, Jie; Liu, Chao; Zang, Shang-fei; Wang, Qiong-hua

    2013-06-01

    A variable-focus cylindrical liquid lens array based on two transparent liquids of different refractive index is demonstrated. An elastic membrane divides a transparent reservoir into two chambers. The two chambers are filled with liquid 1 and liquid 2, respectively, which are of different refractive index. The micro-clapboards help liquid 1, liquid 2 and the elastic membrane form a cylindrical lens array. Driving these two liquids to flow can change the shape of the elastic membrane as well as the focal length. In this design, the gravity effect of liquid can be overcome. A demo lens array of positive optical power is developed and tested. Moreover, a potential application of the proposed lens array for autostereoscopic 3D displays is emphasized.